tildefriends/src/ssb.db.c

#include "ssb.db.h"

#include "log.h"
#include "mem.h"
#include "ssb.h"
#include "trace.h"
#include "util.js.h"

#include "sodium/crypto_hash_sha256.h"
#include "sodium/crypto_sign.h"
#include "sqlite3.h"
#include "uv.h"

#include <stdlib.h>
#include <string.h>

#include <unistd.h>

typedef struct _message_store_t message_store_t;

static void _tf_ssb_db_store_message_work_finish(message_store_t* store);
static void _tf_ssb_db_store_message_after_work(uv_work_t* work, int status);

static void _tf_ssb_db_exec(sqlite3* db, const char* statement)
{
	char* error = NULL;
	int result = sqlite3_exec(db, statement, NULL, NULL, &error);
	if (result != SQLITE_OK)
	{
		tf_printf("Error running '%s': %s.\n", statement, error ? error : sqlite3_errmsg(db));
		abort();
	}
}

static bool _tf_ssb_db_has_rows(sqlite3* db, const char* query)
{
	bool found = false;
	sqlite3_stmt* statement = NULL;
	if (sqlite3_prepare(db, query, -1, &statement, NULL) == SQLITE_OK)
	{
		int result = SQLITE_OK;
		while ((result = sqlite3_step(statement)) == SQLITE_ROW)
		{
			found = true;
		}
		if (result != SQLITE_DONE)
		{
			tf_printf("%s\n", sqlite3_errmsg(db));
			abort();
		}
		sqlite3_finalize(statement);
	}
	else
	{
		tf_printf("%s\n", sqlite3_errmsg(db));
		abort();
	}
	return found;
}

static void _tf_ssb_db_init_internal(sqlite3* db)
{
	sqlite3_extended_result_codes(db, 1);
	_tf_ssb_db_exec(db, "PRAGMA journal_mode = WAL");
	_tf_ssb_db_exec(db, "PRAGMA synchronous = NORMAL");
}

void tf_ssb_db_init_reader(sqlite3* db)
{
	_tf_ssb_db_init_internal(db);
}

void tf_ssb_db_init(tf_ssb_t* ssb)
{
	sqlite3* db = tf_ssb_acquire_db_writer(ssb);
	_tf_ssb_db_init_internal(db);

	sqlite3_stmt* statement = NULL;
	int auto_vacuum = 0;
	if (sqlite3_prepare(db, "PRAGMA auto_vacuum", -1, &statement, NULL) == SQLITE_OK)
	{
		if (sqlite3_step(statement) == SQLITE_ROW)
		{
			auto_vacuum = sqlite3_column_int(statement, 0);
		}
		sqlite3_finalize(statement);
	}
	if (auto_vacuum != 1 /* FULL */)
	{
		tf_printf("Enabling auto-vacuum and performing full vacuum.\n");
		_tf_ssb_db_exec(db, "PRAGMA auto_vacuum = FULL");
		_tf_ssb_db_exec(db, "VACUUM main");
		tf_printf("All clean.\n");
	}

	_tf_ssb_db_exec(db,
		"CREATE TABLE IF NOT EXISTS messages ("
		"  author TEXT,"
		"  id TEXT PRIMARY KEY,"
		"  sequence INTEGER,"
		"  timestamp REAL,"
		"  previous TEXT,"
		"  hash TEXT,"
		"  content BLOB,"
		"  signature TEXT,"
		"  flags INTEGER,"
		"  UNIQUE(author, sequence)"
		")");

	if (_tf_ssb_db_has_rows(db, "SELECT name FROM pragma_table_info('messages') WHERE name = 'content' AND type == 'TEXT'"))
	{
		tf_printf("converting to JSONB\n");
		_tf_ssb_db_exec(db, "DROP TRIGGER IF EXISTS messages_ai_refs");
		_tf_ssb_db_exec(db, "DROP TRIGGER IF EXISTS messages_ad_refs");
		_tf_ssb_db_exec(db, "DROP TRIGGER IF EXISTS messages_ai");
		_tf_ssb_db_exec(db, "DROP TRIGGER IF EXISTS messages_ad");
		_tf_ssb_db_exec(db, "DROP TABLE IF EXISTS messages_fts");
		_tf_ssb_db_exec(db, "BEGIN TRANSACTION");
		_tf_ssb_db_exec(db, "ALTER TABLE messages ADD COLUMN contentb BLOB");
		_tf_ssb_db_exec(db, "UPDATE messages SET contentb = jsonb(content)");
		_tf_ssb_db_exec(db, "ALTER TABLE messages DROP COLUMN content");
		_tf_ssb_db_exec(db, "ALTER TABLE messages RENAME COLUMN contentb TO content");
		_tf_ssb_db_exec(db, "COMMIT TRANSACTION");
	}

	if (_tf_ssb_db_has_rows(db, "SELECT name FROM pragma_table_info('messages') WHERE name = 'sequence_before_author'"))
	{
		tf_printf("Renaming sequence_before_author -> flags.\n");
		_tf_ssb_db_exec(db, "ALTER TABLE messages RENAME COLUMN sequence_before_author TO flags");
	}

	_tf_ssb_db_exec(db, "CREATE INDEX IF NOT EXISTS messages_author_id_index ON messages (author, id)");
	_tf_ssb_db_exec(db, "CREATE INDEX IF NOT EXISTS messages_author_sequence_index ON messages (author, sequence)");
	_tf_ssb_db_exec(db, "CREATE INDEX IF NOT EXISTS messages_author_timestamp_index ON messages (author, timestamp)");
	_tf_ssb_db_exec(db, "CREATE INDEX IF NOT EXISTS messages_timestamp_index ON messages (timestamp)");
	_tf_ssb_db_exec(db,
		"CREATE TABLE IF NOT EXISTS blobs ("
		"  id TEXT PRIMARY KEY,"
		"  content BLOB,"
		"  created INTEGER"
		")");
	_tf_ssb_db_exec(db, "DROP TABLE IF EXISTS blob_wants");
	_tf_ssb_db_exec(db,
		"CREATE TABLE IF NOT EXISTS properties ("
		"  id TEXT,"
		"  key TEXT,"
		"  value TEXT,"
		"  UNIQUE(id, key)"
		")");
	_tf_ssb_db_exec(db,
		"CREATE TABLE IF NOT EXISTS connections ("
		"  host TEXT,"
		"  port INTEGER,"
		"  key TEXT,"
		"  last_attempt INTEGER,"
		"  last_success INTEGER,"
		"  UNIQUE(host, port, key)"
		")");
	_tf_ssb_db_exec(db,
		"CREATE TABLE IF NOT EXISTS identities ("
		"  user TEXT,"
		"  public_key TEXT UNIQUE,"
		"  private_key TEXT UNIQUE"
		")");
	_tf_ssb_db_exec(db, "CREATE INDEX IF NOT EXISTS identities_user ON identities (user, public_key)");

	bool populate_fts = false;
	if (!_tf_ssb_db_has_rows(db, "PRAGMA table_list('messages_fts')"))
	{
		_tf_ssb_db_exec(db, "CREATE VIRTUAL TABLE IF NOT EXISTS messages_fts USING fts5(content, content=messages, content_rowid=rowid)");
		populate_fts = true;
	}

	if (!populate_fts && /* HACK */ false)
	{
		tf_printf("Checking FTS5 integrity...\n");
		if (sqlite3_exec(db, "INSERT INTO messages_fts(messages_fts, rank) VALUES ('integrity-check', 0)", NULL, NULL, NULL) == SQLITE_CORRUPT_VTAB)
		{
			populate_fts = true;
		}
		tf_printf("Done.\n");
	}

	if (populate_fts)
	{
		tf_printf("Populating full-text search...\n");
		_tf_ssb_db_exec(db, "INSERT INTO messages_fts (rowid, content) SELECT rowid, json(content) FROM messages");
		tf_printf("Done.\n");
	}

	_tf_ssb_db_exec(
		db, "CREATE TRIGGER IF NOT EXISTS messages_ai AFTER INSERT ON messages BEGIN INSERT INTO messages_fts(rowid, content) VALUES (new.rowid, json(new.content)); END");
	_tf_ssb_db_exec(db,
		"CREATE TRIGGER IF NOT EXISTS messages_ad AFTER DELETE ON messages BEGIN INSERT INTO messages_fts(messages_fts, rowid, content) VALUES ('delete', old.rowid, "
		"old.content); END");

	if (!_tf_ssb_db_has_rows(db, "PRAGMA table_list('messages_refs')"))
	{
		_tf_ssb_db_exec(db,
			"CREATE TABLE IF NOT EXISTS messages_refs ("
			"  message TEXT, "
			"  ref TEXT, "
			"  UNIQUE(message, ref)"
			")");
		tf_printf("Populating messages_refs...\n");
		_tf_ssb_db_exec(db,
			"INSERT INTO messages_refs(message, ref) "
			"SELECT messages.id, j.value FROM messages, json_tree(messages.content) as j WHERE "
			"j.value LIKE '&%.sha256' OR "
			"j.value LIKE '%%%.sha256' OR "
			"j.value LIKE '@%.ed25519' "
			"ON CONFLICT DO NOTHING");
		tf_printf("Done.\n");
	}

	_tf_ssb_db_exec(db, "DROP TRIGGER IF EXISTS messages_ai_refs");
	_tf_ssb_db_exec(db,
		"CREATE TRIGGER IF NOT EXISTS messages_ai_refs AFTER INSERT ON messages BEGIN "
		"INSERT INTO messages_refs(message, ref) "
		"SELECT DISTINCT new.id, j.value FROM json_tree(new.content) as j WHERE "
		"j.value LIKE '&%.sha256' OR "
		"j.value LIKE '%%%.sha256' OR "
		"j.value LIKE '@%.ed25519' "
		"ON CONFLICT DO NOTHING; END");
	_tf_ssb_db_exec(db, "DROP TRIGGER IF EXISTS messages_ad_refs");
	_tf_ssb_db_exec(db, "CREATE TRIGGER IF NOT EXISTS messages_ad_refs AFTER DELETE ON messages BEGIN DELETE FROM messages_refs WHERE messages_refs.message = old.id; END");

	_tf_ssb_db_exec(db, "CREATE INDEX IF NOT EXISTS messages_refs_message_idx ON messages_refs (message)");
	_tf_ssb_db_exec(db, "CREATE INDEX IF NOT EXISTS messages_refs_ref_idx ON messages_refs (ref)");
	_tf_ssb_db_exec(db, "DROP VIEW IF EXISTS blob_wants_view");
	_tf_ssb_db_exec(db,
		"CREATE VIEW IF NOT EXISTS blob_wants_view (id, timestamp) AS "
		"  SELECT messages_refs.ref AS id, messages.timestamp AS timestamp "
		"  FROM messages_refs "
		"  JOIN messages ON messages.id = messages_refs.message "
		"  LEFT OUTER JOIN blobs ON messages_refs.ref = blobs.id "
		"  WHERE blobs.id IS NULL "
		"    AND LENGTH(messages_refs.ref) = 52 "
		"    AND messages_refs.ref LIKE '&%.sha256'");

	bool need_add_flags = true;
	bool need_convert_timestamp_to_real = false;

	if (sqlite3_prepare(db, "PRAGMA table_info(messages)", -1, &statement, NULL) == SQLITE_OK)
	{
		int result = SQLITE_OK;
		while ((result = sqlite3_step(statement)) == SQLITE_ROW)
		{
			const char* name = (const char*)sqlite3_column_text(statement, 1);
			const char* type = (const char*)sqlite3_column_text(statement, 2);
			if (name && type && strcmp(name, "timestamp") == 0 && strcmp(type, "INTEGER") == 0)
			{
				need_convert_timestamp_to_real = true;
			}
			if (name && strcmp(name, "flags") == 0)
			{
				need_add_flags = false;
			}
		}
		sqlite3_finalize(statement);
	}

	if (need_convert_timestamp_to_real)
	{
		tf_printf("Converting timestamp column from INTEGER to REAL.\n");
		_tf_ssb_db_exec(db, "BEGIN TRANSACTION");
		_tf_ssb_db_exec(db, "DROP INDEX IF EXISTS messages_author_timestamp_index");
		_tf_ssb_db_exec(db, "ALTER TABLE messages ADD COLUMN timestamp_real REAL");
		_tf_ssb_db_exec(db, "UPDATE messages SET timestamp_real = timestamp");
		_tf_ssb_db_exec(db, "ALTER TABLE messages DROP COLUMN timestamp");
		_tf_ssb_db_exec(db, "ALTER TABLE messages RENAME COLUMN timestamp_real TO timestamp");
		_tf_ssb_db_exec(db, "CREATE INDEX IF NOT EXISTS messages_author_timestamp_index ON messages (author, timestamp)");
		_tf_ssb_db_exec(db, "COMMIT TRANSACTION");
	}
	if (need_add_flags)
	{
		tf_printf("Adding flags column.\n");
		_tf_ssb_db_exec(db, "ALTER TABLE messages ADD COLUMN flags INTEGER");
	}
	tf_ssb_release_db_writer(ssb, db);
}

static bool _tf_ssb_db_previous_message_exists(sqlite3* db, const char* author, int64_t sequence, const char* previous)
{
	bool exists = false;
	if (sequence == 1)
	{
		exists = true;
	}
	else
	{
		sqlite3_stmt* statement;
		if (sqlite3_prepare(db, "SELECT COUNT(*) FROM messages WHERE author = ?1 AND sequence = ?2 AND id = ?3", -1, &statement, NULL) == SQLITE_OK)
		{
			if (sqlite3_bind_text(statement, 1, author, -1, NULL) == SQLITE_OK && sqlite3_bind_int64(statement, 2, sequence - 1) == SQLITE_OK &&
				sqlite3_bind_text(statement, 3, previous, -1, NULL) == SQLITE_OK && sqlite3_step(statement) == SQLITE_ROW)
			{
				exists = sqlite3_column_int(statement, 0) != 0;
			}
			sqlite3_finalize(statement);
		}
	}
	return exists;
}

static int64_t _tf_ssb_db_store_message_raw(tf_ssb_t* ssb, const char* id, const char* previous, const char* author, int64_t sequence, double timestamp, const char* content,
	size_t content_len, const char* signature, int flags)
{
	sqlite3* db = tf_ssb_acquire_db_writer(ssb);
	int64_t last_row_id = -1;

	if (_tf_ssb_db_previous_message_exists(db, author, sequence, previous))
	{
		const char* query = "INSERT INTO messages (id, previous, author, sequence, timestamp, content, hash, signature, flags) VALUES (?, ?, ?, ?, ?, jsonb(?), "
							"?, ?, ?) ON CONFLICT DO NOTHING";
		sqlite3_stmt* statement;
		if (sqlite3_prepare(db, query, -1, &statement, NULL) == SQLITE_OK)
		{
			if (sqlite3_bind_text(statement, 1, id, -1, NULL) == SQLITE_OK &&
				(previous ? sqlite3_bind_text(statement, 2, previous, -1, NULL) : sqlite3_bind_null(statement, 2)) == SQLITE_OK &&
				sqlite3_bind_text(statement, 3, author, -1, NULL) == SQLITE_OK && sqlite3_bind_int64(statement, 4, sequence) == SQLITE_OK &&
				sqlite3_bind_double(statement, 5, timestamp) == SQLITE_OK && sqlite3_bind_text(statement, 6, content, content_len, NULL) == SQLITE_OK &&
				sqlite3_bind_text(statement, 7, "sha256", 6, NULL) == SQLITE_OK && sqlite3_bind_text(statement, 8, signature, -1, NULL) == SQLITE_OK &&
				sqlite3_bind_int(statement, 9, flags) == SQLITE_OK)
			{
				int r = sqlite3_step(statement);
				if (r != SQLITE_DONE)
				{
					tf_printf("_tf_ssb_db_store_message_raw: %s\n", sqlite3_errmsg(db));
				}
				if (r == SQLITE_DONE && sqlite3_changes(db) != 0)
				{
					last_row_id = sqlite3_last_insert_rowid(db);
				}
			}
			else
			{
				tf_printf("bind failed\n");
			}
			sqlite3_finalize(statement);
		}
		else
		{
			tf_printf("%s: prepare failed: %s\n", __FUNCTION__, sqlite3_errmsg(db));
		}
	}
	else
	{
		tf_printf("%p: Previous message doesn't exist for author=%s sequence=%" PRId64 ".\n", db, author, sequence);
	}
	tf_ssb_release_db_writer(ssb, db);
	return last_row_id;
}

static char* _tf_ssb_db_get_message_blob_wants(tf_ssb_t* ssb, int64_t rowid)
{
	sqlite3* db = tf_ssb_acquire_db_reader(ssb);
	sqlite3_stmt* statement;
	char* result = NULL;
	size_t size = 0;

	if (sqlite3_prepare(db,
			"SELECT DISTINCT json.value FROM messages, json_tree(messages.content) AS json LEFT OUTER JOIN blobs ON json.value = blobs.id WHERE messages.rowid = ?1 AND "
			"json.value LIKE '&%%.sha256' AND length(json.value) = ?2 AND blobs.content IS NULL",
			-1, &statement, NULL) == SQLITE_OK)
	{
		if (sqlite3_bind_int64(statement, 1, rowid) == SQLITE_OK && sqlite3_bind_int(statement, 2, k_blob_id_len - 1) == SQLITE_OK)
		{
			int r = SQLITE_OK;
			while ((r = sqlite3_step(statement)) == SQLITE_ROW)
			{
				int id_size = sqlite3_column_bytes(statement, 0);
				const uint8_t* id = sqlite3_column_text(statement, 0);
				result = tf_resize_vec(result, size + id_size + 1);
				memcpy(result + size, id, id_size + 1);
				size += id_size + 1;
			}
			if (r != SQLITE_DONE)
			{
				tf_printf("%s\n", sqlite3_errmsg(db));
			}
		}
		else
		{
			tf_printf("bind failed: %s\n", sqlite3_errmsg(db));
		}
		sqlite3_finalize(statement);
	}
	else
	{
		tf_printf("%s: prepare failed: %s\n", __FUNCTION__, sqlite3_errmsg(db));
	}
	result = tf_realloc(result, size + 1);
	result[size] = '\0';

	tf_ssb_release_db_reader(ssb, db);
	return result;
}

typedef struct _message_store_t
{
	uv_work_t work;
	tf_ssb_t* ssb;
	char id[k_id_base64_len];
	char signature[512];
	int flags;
	char previous[k_id_base64_len];
	char author[k_id_base64_len];
	int64_t sequence;
	double timestamp;
	const char* content;
	size_t length;

	bool out_stored;
	char* out_blob_wants;

	tf_ssb_db_store_message_callback_t* callback;
	void* user_data;

	message_store_t* next;
} message_store_t;

static void _tf_ssb_db_store_message_work(uv_work_t* work)
{
	message_store_t* store = work->data;
	tf_ssb_record_thread_busy(store->ssb, true);
	tf_trace_t* trace = tf_ssb_get_trace(store->ssb);
	tf_trace_begin(trace, "message_store_work");
	int64_t last_row_id = _tf_ssb_db_store_message_raw(store->ssb, store->id, *store->previous ? store->previous : NULL, store->author, store->sequence, store->timestamp,
		store->content, store->length, store->signature, store->flags);
	if (last_row_id != -1)
	{
		store->out_stored = true;
		store->out_blob_wants = _tf_ssb_db_get_message_blob_wants(store->ssb, last_row_id);
	}
	tf_trace_end(trace);
	tf_ssb_record_thread_busy(store->ssb, false);
}

static void _wake_up_queue(tf_ssb_t* ssb, tf_ssb_store_queue_t* queue)
{
	if (!queue->running)
	{
		message_store_t* next = queue->head;
		if (next)
		{
			queue->head = next->next;
			if (queue->tail == next)
			{
				queue->tail = NULL;
			}
			next->next = NULL;
			queue->running = true;
			int r = uv_queue_work(tf_ssb_get_loop(ssb), &next->work, _tf_ssb_db_store_message_work, _tf_ssb_db_store_message_after_work);
			if (r)
			{
				_tf_ssb_db_store_message_work_finish(next);
			}
		}
	}
}

static void _tf_ssb_db_store_message_work_finish(message_store_t* store)
{
	JSContext* context = tf_ssb_get_context(store->ssb);
	if (store->callback)
	{
		store->callback(store->id, store->out_stored, store->user_data);
	}
	JS_FreeCString(context, store->content);
	tf_ssb_store_queue_t* queue = tf_ssb_get_store_queue(store->ssb);
	queue->running = false;
	_wake_up_queue(store->ssb, queue);
	tf_free(store);
}

static void _tf_ssb_db_store_message_after_work(uv_work_t* work, int status)
{
	message_store_t* store = work->data;
	tf_trace_t* trace = tf_ssb_get_trace(store->ssb);
	tf_trace_begin(trace, "message_store_after_work");
	if (store->out_stored)
	{
		tf_trace_begin(trace, "notify_message_added");
		JSContext* context = tf_ssb_get_context(store->ssb);
		JSValue formatted =
			tf_ssb_format_message(context, store->previous, store->author, store->sequence, store->timestamp, "sha256", store->content, store->signature, store->flags);
		JSValue message = JS_NewObject(context);
		JS_SetPropertyStr(context, message, "key", JS_NewString(context, store->id));
		JS_SetPropertyStr(context, message, "value", formatted);
		char timestamp_string[256];
		snprintf(timestamp_string, sizeof(timestamp_string), "%f", store->timestamp);
		JS_SetPropertyStr(context, message, "timestamp", JS_NewString(context, timestamp_string));
		tf_ssb_notify_message_added(store->ssb, store->id, message);
		JS_FreeValue(context, message);
		tf_trace_end(trace);
	}
	if (store->out_blob_wants)
	{
		tf_trace_begin(trace, "notify_blob_wants_added");
		for (char* p = store->out_blob_wants; *p; p = p + strlen(p))
		{
			tf_ssb_notify_blob_want_added(store->ssb, p);
		}
		tf_free(store->out_blob_wants);
		tf_trace_end(trace);
	}
	_tf_ssb_db_store_message_work_finish(store);
	tf_trace_end(trace);
}

void tf_ssb_db_store_message(
	tf_ssb_t* ssb, JSContext* context, const char* id, JSValue val, const char* signature, int flags, tf_ssb_db_store_message_callback_t* callback, void* user_data)
{
	JSValue previousval = JS_GetPropertyStr(context, val, "previous");
	const char* previous = JS_IsNull(previousval) ? NULL : JS_ToCString(context, previousval);
	JS_FreeValue(context, previousval);

	JSValue authorval = JS_GetPropertyStr(context, val, "author");
	const char* author = JS_ToCString(context, authorval);
	JS_FreeValue(context, authorval);

	int64_t sequence = -1;
	JSValue sequenceval = JS_GetPropertyStr(context, val, "sequence");
	JS_ToInt64(context, &sequence, sequenceval);
	JS_FreeValue(context, sequenceval);

	double timestamp = -1.0;
	JSValue timestampval = JS_GetPropertyStr(context, val, "timestamp");
	JS_ToFloat64(context, &timestamp, timestampval);
	JS_FreeValue(context, timestampval);

	JSValue contentval = JS_GetPropertyStr(context, val, "content");
	JSValue content = JS_JSONStringify(context, contentval, JS_NULL, JS_NULL);
	size_t content_len;
	const char* contentstr = JS_ToCStringLen(context, &content_len, content);
	JS_FreeValue(context, content);
	JS_FreeValue(context, contentval);

	message_store_t* store = tf_malloc(sizeof(message_store_t));
	*store = (message_store_t)
	{
		.work =
		{
			.data = store,
		},
		.ssb = ssb,
		.sequence = sequence,
		.timestamp = timestamp,
		.content = contentstr,
		.length = content_len,
		.flags = flags,

		.callback = callback,
		.user_data = user_data,
	};
	snprintf(store->id, sizeof(store->id), "%s", id);
	snprintf(store->previous, sizeof(store->previous), "%s", previous ? previous : "");
	snprintf(store->author, sizeof(store->author), "%s", author);
	snprintf(store->signature, sizeof(store->signature), "%s", signature);
	JS_FreeCString(context, author);
	JS_FreeCString(context, previous);

	tf_ssb_store_queue_t* queue = tf_ssb_get_store_queue(ssb);
	if (queue->tail)
	{
		message_store_t* tail = queue->tail;
		tail->next = store;
		queue->tail = store;
	}
	else
	{
		queue->head = store;
		queue->tail = store;
	}
	_wake_up_queue(ssb, queue);
}

bool tf_ssb_db_message_content_get(tf_ssb_t* ssb, const char* id, uint8_t** out_blob, size_t* out_size)
{
	bool result = false;
	sqlite3_stmt* statement;
	sqlite3* db = tf_ssb_acquire_db_reader(ssb);
	const char* query = "SELECT json(content) FROM messages WHERE id = ?";
	if (sqlite3_prepare(db, query, -1, &statement, NULL) == SQLITE_OK)
	{
		if (sqlite3_bind_text(statement, 1, id, -1, NULL) == SQLITE_OK && sqlite3_step(statement) == SQLITE_ROW)
		{
			const uint8_t* blob = sqlite3_column_blob(statement, 0);
			int size = sqlite3_column_bytes(statement, 0);
			if (out_blob)
			{
				*out_blob = tf_malloc(size + 1);
				memcpy(*out_blob, blob, size);
				(*out_blob)[size] = '\0';
			}
			if (out_size)
			{
				*out_size = size;
			}
			result = true;
		}
		sqlite3_finalize(statement);
	}
	tf_ssb_release_db_reader(ssb, db);
	return result;
}

bool tf_ssb_db_blob_has(tf_ssb_t* ssb, const char* id)
{
	bool result = false;
	sqlite3_stmt* statement;
	sqlite3* db = tf_ssb_acquire_db_reader(ssb);
	const char* query = "SELECT COUNT(*) FROM blobs WHERE id = ?1";
	if (sqlite3_prepare(db, query, -1, &statement, NULL) == SQLITE_OK)
	{
		if (sqlite3_bind_text(statement, 1, id, -1, NULL) == SQLITE_OK && sqlite3_step(statement) == SQLITE_ROW)
		{
			result = sqlite3_column_int64(statement, 0) != 0;
		}
		sqlite3_finalize(statement);
	}
	tf_ssb_release_db_reader(ssb, db);
	return result;
}

bool tf_ssb_db_blob_get(tf_ssb_t* ssb, const char* id, uint8_t** out_blob, size_t* out_size)
{
	bool result = false;
	sqlite3_stmt* statement;
	sqlite3* db = tf_ssb_acquire_db_reader(ssb);
	const char* query = "SELECT content FROM blobs WHERE id = ?1";
	if (sqlite3_prepare(db, query, -1, &statement, NULL) == SQLITE_OK)
	{
		if (sqlite3_bind_text(statement, 1, id, -1, NULL) == SQLITE_OK && sqlite3_step(statement) == SQLITE_ROW)
		{
			const uint8_t* blob = sqlite3_column_blob(statement, 0);
			int size = sqlite3_column_bytes(statement, 0);
			if (out_blob)
			{
				*out_blob = tf_malloc(size + 1);
				if (size)
				{
					memcpy(*out_blob, blob, size);
				}
				(*out_blob)[size] = '\0';
			}
			if (out_size)
			{
				*out_size = size;
			}
			result = true;
		}
		sqlite3_finalize(statement);
	}
	tf_ssb_release_db_reader(ssb, db);
	return result;
}

typedef struct _blob_store_work_t
{
	uv_work_t work;
	tf_ssb_t* ssb;
	const uint8_t* blob;
	size_t size;
	char id[k_blob_id_len];
	bool is_new;
	tf_ssb_db_blob_store_callback_t* callback;
	void* user_data;
} blob_store_work_t;

static void _tf_ssb_db_blob_store_work(uv_work_t* work)
{
	blob_store_work_t* blob_work = work->data;
	tf_ssb_record_thread_busy(blob_work->ssb, true);
	tf_trace_t* trace = tf_ssb_get_trace(blob_work->ssb);
	tf_trace_begin(trace, "blob_store_work");
	tf_ssb_db_blob_store(blob_work->ssb, blob_work->blob, blob_work->size, blob_work->id, sizeof(blob_work->id), &blob_work->is_new);
	tf_trace_end(trace);
	tf_ssb_record_thread_busy(blob_work->ssb, false);
}

static void _tf_ssb_db_blob_store_after_work(uv_work_t* work, int status)
{
	blob_store_work_t* blob_work = work->data;
	tf_trace_t* trace = tf_ssb_get_trace(blob_work->ssb);
	tf_trace_begin(trace, "blob_store_after_work");
	if (status == 0 && *blob_work->id)
	{
		tf_ssb_notify_blob_stored(blob_work->ssb, blob_work->id);
	}
	if (status != 0)
	{
		tf_printf("tf_ssb_db_blob_store_async -> uv_queue_work failed asynchronously: %s\n", uv_strerror(status));
	}
	if (blob_work->callback)
	{
		blob_work->callback(status == 0 ? blob_work->id : NULL, blob_work->is_new, blob_work->user_data);
	}
	tf_trace_end(trace);
	tf_free(blob_work);
}

void tf_ssb_db_blob_store_async(tf_ssb_t* ssb, const uint8_t* blob, size_t size, tf_ssb_db_blob_store_callback_t* callback, void* user_data)
{
	blob_store_work_t* work = tf_malloc(sizeof(blob_store_work_t));
	*work = (blob_store_work_t)
	{
		.work =
		{
			.data = work,
		},
		.ssb = ssb,
		.blob = blob,
		.size = size,
		.callback = callback,
		.user_data = user_data,
	};
	int r = uv_queue_work(tf_ssb_get_loop(ssb), &work->work, _tf_ssb_db_blob_store_work, _tf_ssb_db_blob_store_after_work);
	if (r)
	{
		tf_printf("tf_ssb_db_blob_store_async -> uv_queue_work failed immediately: %s\n", uv_strerror(r));
		if (callback)
		{
			callback(NULL, false, user_data);
		}
		tf_free(work);
	}
}

bool tf_ssb_db_blob_store(tf_ssb_t* ssb, const uint8_t* blob, size_t size, char* out_id, size_t out_id_size, bool* out_new)
{
	bool result = false;

	uint8_t hash[crypto_hash_sha256_BYTES];
	crypto_hash_sha256(hash, blob, size);

	char hash64[256];
	tf_base64_encode(hash, sizeof(hash), hash64, sizeof(hash64));

	char id[512];
	snprintf(id, sizeof(id), "&%s.sha256", hash64);

	int rows = 0;

	sqlite3* db = tf_ssb_acquire_db_writer(ssb);
	sqlite3_stmt* statement;
	if (sqlite3_prepare(db, "INSERT INTO blobs (id, content, created) VALUES (?1, ?2, CAST(strftime('%s') AS INTEGER)) ON CONFLICT DO NOTHING", -1, &statement, NULL) == SQLITE_OK)
	{
		if (sqlite3_bind_text(statement, 1, id, -1, NULL) == SQLITE_OK && sqlite3_bind_blob(statement, 2, blob, size, NULL) == SQLITE_OK)
		{
			result = sqlite3_step(statement) == SQLITE_DONE;
			rows = sqlite3_changes(db);
		}
		else
		{
			tf_printf("bind failed: %s\n", sqlite3_errmsg(db));
		}
		sqlite3_finalize(statement);
	}
	else
	{
		tf_printf("%s: prepare failed: %s\n", __FUNCTION__, sqlite3_errmsg(db));
	}
	tf_ssb_release_db_writer(ssb, db);

	if (rows)
	{
		if (!out_new)
		{
			tf_printf("blob stored %s %zd => %d\n", id, size, result);
		}
	}

	if (result && out_id)
	{
		snprintf(out_id, out_id_size, "%s", id);
	}
	if (out_new)
	{
		*out_new = rows != 0;
	}
	return result;
}

bool tf_ssb_db_get_message_by_author_and_sequence(
	tf_ssb_t* ssb, const char* author, int64_t sequence, char* out_message_id, size_t out_message_id_size, double* out_timestamp, char** out_content)
{
	bool found = false;
	sqlite3_stmt* statement;
	const char* query = "SELECT id, timestamp, json(content) FROM messages WHERE author = ?1 AND sequence = ?2";
	sqlite3* db = tf_ssb_acquire_db_reader(ssb);
	if (sqlite3_prepare(db, query, -1, &statement, NULL) == SQLITE_OK)
	{
		if (sqlite3_bind_text(statement, 1, author, -1, NULL) == SQLITE_OK && sqlite3_bind_int64(statement, 2, sequence) == SQLITE_OK && sqlite3_step(statement) == SQLITE_ROW)
		{
			if (out_message_id)
			{
				strncpy(out_message_id, (const char*)sqlite3_column_text(statement, 0), out_message_id_size - 1);
			}
			if (out_timestamp)
			{
				*out_timestamp = sqlite3_column_double(statement, 1);
			}
			if (out_content)
			{
				*out_content = tf_strdup((const char*)sqlite3_column_text(statement, 2));
			}
			found = true;
		}
		sqlite3_finalize(statement);
	}
	else
	{
		tf_printf("%s: prepare failed: %s\n", __FUNCTION__, sqlite3_errmsg(db));
	}
	tf_ssb_release_db_reader(ssb, db);
	return found;
}

bool tf_ssb_db_get_latest_message_by_author(tf_ssb_t* ssb, const char* author, int64_t* out_sequence, char* out_message_id, size_t out_message_id_size)
{
	bool found = false;
	sqlite3_stmt* statement;
	sqlite3* db = tf_ssb_acquire_db_reader(ssb);
	const char* query = "SELECT id, sequence FROM messages WHERE author = ?1 AND sequence = (SELECT MAX(sequence) FROM messages WHERE author = ?1)";
	if (sqlite3_prepare(db, query, -1, &statement, NULL) == SQLITE_OK)
	{
		if (sqlite3_bind_text(statement, 1, author, -1, NULL) == SQLITE_OK && sqlite3_step(statement) == SQLITE_ROW)
		{
			if (out_sequence)
			{
				*out_sequence = sqlite3_column_int64(statement, 1);
			}
			if (out_message_id)
			{
				strncpy(out_message_id, (const char*)sqlite3_column_text(statement, 0), out_message_id_size - 1);
			}
			found = true;
		}
		sqlite3_finalize(statement);
	}
	else
	{
		tf_printf("%s: prepare failed: %s\n", __FUNCTION__, sqlite3_errmsg(db));
	}
	tf_ssb_release_db_reader(ssb, db);
	return found;
}

static JSValue _tf_ssb_sqlite_bind_json(JSContext* context, sqlite3* db, sqlite3_stmt* statement, JSValue binds)
{
	if (JS_IsUndefined(binds))
	{
		return JS_UNDEFINED;
	}
	if (!JS_IsArray(context, binds))
	{
		return JS_ThrowTypeError(context, "Expected bind parameters to be an array.");
	}

	JSValue result = JS_UNDEFINED;
	int32_t length = tf_util_get_length(context, binds);
	for (int i = 0; i < length && JS_IsUndefined(result); i++)
	{
		JSValue value = JS_GetPropertyUint32(context, binds, i);
		if (JS_IsNumber(value))
		{
			int64_t number = 0;
			JS_ToInt64(context, &number, value);
			if (sqlite3_bind_int64(statement, i + 1, number) != SQLITE_OK)
			{
				result = JS_ThrowInternalError(context, "Failed to bind: %s.", sqlite3_errmsg(db));
			}
		}
		else if (JS_IsBool(value))
		{
			if (sqlite3_bind_int(statement, i + 1, JS_ToBool(context, value) ? 1 : 0) != SQLITE_OK)
			{
				result = JS_ThrowInternalError(context, "Failed to bind: %s.", sqlite3_errmsg(db));
			}
		}
		else if (JS_IsNull(value))
		{
			if (sqlite3_bind_null(statement, i + 1) != SQLITE_OK)
			{
				result = JS_ThrowInternalError(context, "Failed to bind: %s.", sqlite3_errmsg(db));
			}
		}
		else
		{
			size_t str_len = 0;
			const char* str = JS_ToCStringLen(context, &str_len, value);
			if (str)
			{
				if (sqlite3_bind_text(statement, i + 1, str, str_len, SQLITE_TRANSIENT) != SQLITE_OK)
				{
					result = JS_ThrowInternalError(context, "Failed to bind: %s.", sqlite3_errmsg(db));
				}
				JS_FreeCString(context, str);
			}
			else
			{
				result = JS_ThrowInternalError(context, "Could not convert bind argument %d to string.", i);
			}
		}
		JS_FreeValue(context, value);
	}
	return result;
}

static JSValue _tf_ssb_sqlite_row_to_json(JSContext* context, sqlite3_stmt* row)
{
	JSValue result = JS_NewObject(context);
	for (int i = 0; i < sqlite3_column_count(row); i++)
	{
		const char* name = sqlite3_column_name(row, i);
		switch (sqlite3_column_type(row, i))
		{
		case SQLITE_INTEGER:
			JS_SetPropertyStr(context, result, name, JS_NewInt64(context, sqlite3_column_int64(row, i)));
			break;
		case SQLITE_FLOAT:
			JS_SetPropertyStr(context, result, name, JS_NewFloat64(context, sqlite3_column_double(row, i)));
			break;
		case SQLITE_TEXT:
			JS_SetPropertyStr(context, result, name, JS_NewStringLen(context, (const char*)sqlite3_column_text(row, i), sqlite3_column_bytes(row, i)));
			break;
		case SQLITE_BLOB:
			JS_SetPropertyStr(context, result, name, JS_NewArrayBufferCopy(context, sqlite3_column_blob(row, i), sqlite3_column_bytes(row, i)));
			break;
		case SQLITE_NULL:
			JS_SetPropertyStr(context, result, name, JS_NULL);
			break;
		}
	}
	return result;
}

int tf_ssb_sqlite_authorizer(void* user_data, int action_code, const char* arg0, const char* arg1, const char* arg2, const char* arg3)
{
	int result = SQLITE_DENY;
	switch (action_code)
	{
	case SQLITE_SELECT:
	case SQLITE_FUNCTION:
		result = SQLITE_OK;
		break;
	case SQLITE_READ:
		result = (strcmp(arg0, "blob_wants_view") == 0 || strcmp(arg0, "json_each") == 0 || strcmp(arg0, "json_tree") == 0 || strcmp(arg0, "messages") == 0 ||
					 strcmp(arg0, "messages_fts") == 0 || strcmp(arg0, "messages_fts_idx") == 0 || strcmp(arg0, "messages_fts_config") == 0 || strcmp(arg0, "messages_refs") == 0 ||
					 strcmp(arg0, "messages_refs_message_idx") == 0 || strcmp(arg0, "messages_refs_ref_idx") == 0 || strcmp(arg0, "sqlite_master") == 0 || false)
			? SQLITE_OK
			: SQLITE_DENY;
		break;
	case SQLITE_PRAGMA:
		result = strcmp(arg0, "data_version") == 0 ? SQLITE_OK : SQLITE_DENY;
		break;
	case SQLITE_UPDATE:
		result = strcmp(arg0, "sqlite_master") == 0 ? SQLITE_OK : SQLITE_DENY;
		break;
	}
	if (result != SQLITE_OK)
	{
		tf_printf("Denying sqlite access to %d %s %s %s %s\n", action_code, arg0, arg1, arg2, arg3);
		fflush(stdout);
	}
	return result;
}

JSValue tf_ssb_db_visit_query(tf_ssb_t* ssb, const char* query, const JSValue binds, void (*callback)(JSValue row, void* user_data), void* user_data)
{
	JSValue result = JS_UNDEFINED;
	sqlite3* db = tf_ssb_acquire_db_reader_restricted(ssb);
	JSContext* context = tf_ssb_get_context(ssb);
	sqlite3_stmt* statement;
	if (sqlite3_prepare(db, query, -1, &statement, NULL) == SQLITE_OK)
	{
		JSValue bind_result = _tf_ssb_sqlite_bind_json(context, db, statement, binds);
		if (JS_IsUndefined(bind_result))
		{
			int r = SQLITE_OK;
			while ((r = sqlite3_step(statement)) == SQLITE_ROW)
			{
				JSValue row = _tf_ssb_sqlite_row_to_json(context, statement);
				tf_trace_t* trace = tf_ssb_get_trace(ssb);
				tf_trace_begin(trace, "callback");
				callback(row, user_data);
				tf_trace_end(trace);
				JS_FreeValue(context, row);
			}
			if (r != SQLITE_DONE)
			{
				result = JS_ThrowInternalError(context, "SQL Error %s: running \"%s\".", sqlite3_errmsg(db), query);
			}
		}
		else
		{
			result = bind_result;
		}
		sqlite3_finalize(statement);
	}
	else
	{
		result = JS_ThrowInternalError(context, "SQL Error %s: preparing \"%s\".", sqlite3_errmsg(db), query);
	}
	tf_ssb_release_db_reader(ssb, db);
	return result;
}

JSValue tf_ssb_format_message(
	JSContext* context, const char* previous, const char* author, int64_t sequence, double timestamp, const char* hash, const char* content, const char* signature, int flags)
{
	JSValue value = JS_NewObject(context);
	JS_SetPropertyStr(context, value, "previous", (previous && *previous) ? JS_NewString(context, previous) : JS_NULL);
	if (flags & k_tf_ssb_message_flag_sequence_before_author)
	{
		JS_SetPropertyStr(context, value, "sequence", JS_NewInt64(context, sequence));
		JS_SetPropertyStr(context, value, "author", JS_NewString(context, author));
	}
	else
	{
		JS_SetPropertyStr(context, value, "author", JS_NewString(context, author));
		JS_SetPropertyStr(context, value, "sequence", JS_NewInt64(context, sequence));
	}
	JS_SetPropertyStr(context, value, "timestamp", JS_NewFloat64(context, timestamp));
	JS_SetPropertyStr(context, value, "hash", JS_NewString(context, hash));
	JS_SetPropertyStr(context, value, "content", JS_ParseJSON(context, content, strlen(content), NULL));
	JS_SetPropertyStr(context, value, "signature", JS_NewString(context, signature));
	return value;
}

int tf_ssb_db_identity_get_count_for_user(tf_ssb_t* ssb, const char* user)
{
	int count = 0;
	sqlite3* db = tf_ssb_acquire_db_reader(ssb);
	sqlite3_stmt* statement = NULL;
	if (sqlite3_prepare(db, "SELECT COUNT(*) FROM identities WHERE user = ?", -1, &statement, NULL) == SQLITE_OK)
	{
		if (sqlite3_bind_text(statement, 1, user, -1, NULL) == SQLITE_OK)
		{
			if (sqlite3_step(statement) == SQLITE_ROW)
			{
				count = sqlite3_column_int(statement, 0);
			}
		}
		sqlite3_finalize(statement);
	}
	tf_ssb_release_db_reader(ssb, db);
	return count;
}

bool tf_ssb_db_identity_create(tf_ssb_t* ssb, const char* user, uint8_t* out_public_key, uint8_t* out_private_key)
{
	int count = tf_ssb_db_identity_get_count_for_user(ssb, user);
	if (count < 16)
	{
		char public[512];
		char private[512];
		tf_ssb_generate_keys_buffer(public, sizeof(public), private, sizeof(private));
		if (tf_ssb_db_identity_add(ssb, user, public, private))
		{
			tf_ssb_id_str_to_bin(out_public_key, public);
			tf_ssb_id_str_to_bin(out_private_key, private);
			return true;
		}
	}
	return false;
}

bool tf_ssb_db_identity_add(tf_ssb_t* ssb, const char* user, const char* public_key, const char* private_key)
{
	bool added = false;
	sqlite3* db = tf_ssb_acquire_db_writer(ssb);
	sqlite3_stmt* statement = NULL;
	if (sqlite3_prepare(db, "INSERT INTO identities (user, public_key, private_key) VALUES (?, ?, ?) ON CONFLICT DO NOTHING", -1, &statement, NULL) == SQLITE_OK)
	{
		if (sqlite3_bind_text(statement, 1, user, -1, NULL) == SQLITE_OK && sqlite3_bind_text(statement, 2, public_key, -1, NULL) == SQLITE_OK &&
			sqlite3_bind_text(statement, 3, private_key, -1, NULL) == SQLITE_OK)
		{
			added = sqlite3_step(statement) == SQLITE_DONE && sqlite3_changes(db) != 0;
			if (!added)
			{
				tf_printf("Unable to add identity: %s.\n", sqlite3_errmsg(db));
			}
		}
		sqlite3_finalize(statement);
	}
	tf_ssb_release_db_writer(ssb, db);
	return added;
}

bool tf_ssb_db_identity_delete(tf_ssb_t* ssb, const char* user, const char* public_key)
{
	bool removed = false;
	sqlite3* db = tf_ssb_acquire_db_writer(ssb);
	sqlite3_stmt* statement = NULL;
	tf_printf("deleting [%s] [%s]\n", user, public_key);
	if (sqlite3_prepare(db, "DELETE FROM identities WHERE user = ? AND public_key = ?", -1, &statement, NULL) == SQLITE_OK)
	{
		if (sqlite3_bind_text(statement, 1, user, -1, NULL) == SQLITE_OK && sqlite3_bind_text(statement, 2, public_key, -1, NULL) == SQLITE_OK)
		{
			removed = sqlite3_step(statement) == SQLITE_DONE && sqlite3_changes(db) != 0;
			if (!removed)
			{
				tf_printf("Unable to delete identity: %s.\n", sqlite3_errmsg(db));
			}
		}
		sqlite3_finalize(statement);
	}
	tf_ssb_release_db_writer(ssb, db);
	return removed;
}

void tf_ssb_db_identity_visit(tf_ssb_t* ssb, const char* user, void (*callback)(const char* identity, void* user_data), void* user_data)
{
	sqlite3* db = tf_ssb_acquire_db_reader(ssb);
	sqlite3_stmt* statement = NULL;
	if (sqlite3_prepare(db, "SELECT public_key FROM identities WHERE user = ? ORDER BY public_key", -1, &statement, NULL) == SQLITE_OK)
	{
		if (sqlite3_bind_text(statement, 1, user, -1, NULL) == SQLITE_OK)
		{
			while (sqlite3_step(statement) == SQLITE_ROW)
			{
				callback((const char*)sqlite3_column_text(statement, 0), user_data);
			}
		}
		sqlite3_finalize(statement);
	}
	tf_ssb_release_db_reader(ssb, db);
}

void tf_ssb_db_identity_visit_all(tf_ssb_t* ssb, void (*callback)(const char* identity, void* user_data), void* user_data)
{
	sqlite3* db = tf_ssb_acquire_db_reader(ssb);
	sqlite3_stmt* statement = NULL;
	if (sqlite3_prepare(db, "SELECT public_key FROM identities ORDER BY public_key", -1, &statement, NULL) == SQLITE_OK)
	{
		while (sqlite3_step(statement) == SQLITE_ROW)
		{
			callback((const char*)sqlite3_column_text(statement, 0), user_data);
		}
		sqlite3_finalize(statement);
	}
	tf_ssb_release_db_reader(ssb, db);
}

bool tf_ssb_db_identity_get_private_key(tf_ssb_t* ssb, const char* user, const char* public_key, uint8_t* out_private_key, size_t private_key_size)
{
	bool success = false;
	if (out_private_key)
	{
		memset(out_private_key, 0, private_key_size);
	}
	sqlite3* db = tf_ssb_acquire_db_reader(ssb);
	sqlite3_stmt* statement = NULL;
	if (sqlite3_prepare(db, "SELECT private_key FROM identities WHERE user = ? AND public_key = ?", -1, &statement, NULL) == SQLITE_OK)
	{
		if (sqlite3_bind_text(statement, 1, user, -1, NULL) == SQLITE_OK &&
			sqlite3_bind_text(statement, 2, (public_key && *public_key == '@') ? public_key + 1 : public_key, -1, NULL) == SQLITE_OK)
		{
			if (sqlite3_step(statement) == SQLITE_ROW)
			{
				const char* key = (const char*)sqlite3_column_text(statement, 0);
				if (out_private_key && private_key_size)
				{
					int r = tf_base64_decode(key, sqlite3_column_bytes(statement, 0) - strlen(".ed25519"), out_private_key, private_key_size);
					success = r > 0;
				}
				else
				{
					success = true;
				}
			}
		}
		sqlite3_finalize(statement);
	}
	tf_ssb_release_db_reader(ssb, db);
	return success;
}

typedef struct _following_t following_t;

typedef struct _following_t
{
	char id[k_id_base64_len];
	following_t** following;
	following_t** blocking;
	int following_count;
	int blocking_count;
	int depth;
	int ref_count;
	int block_ref_count;
	bool populated;
} following_t;

static int _following_compare(const void* a, const void* b)
{
	const char* ida = a;
	const following_t* const* followingb = b;
	return strcmp(ida, (*followingb)->id);
}

static bool _has_following_entry(const char* id, following_t** list, int count)
{
	return count ? bsearch(id, list, count, sizeof(following_t*), _following_compare) != 0 : false;
}

static bool _add_following_entry(following_t*** list, int* count, following_t* add)
{
	int index = tf_util_insert_index(add->id, *list, *count, sizeof(following_t*), _following_compare);
	if (index >= *count || strcmp(add->id, (*list)[index]->id) != 0)
	{
		*list = tf_resize_vec(*list, sizeof(**list) * (*count + 1));
		if (*count - index)
		{
			memmove(*list + index + 1, *list + index, sizeof(following_t*) * (*count - index));
		}
		(*list)[index] = add;
		(*count)++;
		return true;
	}
	return false;
}

static bool _remove_following_entry(following_t*** list, int* count, following_t* remove)
{
	int index = tf_util_insert_index(remove->id, *list, *count, sizeof(following_t*), _following_compare);
	if (index < *count && strcmp(remove->id, (*list)[index]->id) == 0)
	{
		if (*count - index > 1)
		{
			memmove(*list + index, *list + index + 1, sizeof(following_t*) * (*count - index - 1));
		}
		*list = tf_resize_vec(*list, sizeof(**list) * (*count - 1));
		(*count)--;
		return true;
	}
	return false;
}

typedef struct _block_node_t block_node_t;

typedef struct _block_node_t
{
	following_t* entry;
	block_node_t* parent;
} block_node_t;

static bool _is_blocked_by_active_blocks(const char* id, const block_node_t* blocks)
{
	for (const block_node_t* b = blocks; b; b = b->parent)
	{
		if (_has_following_entry(id, b->entry->blocking, b->entry->blocking_count))
		{
			return true;
		}
	}
	return false;
}

static following_t* _make_following_node(const char* id, following_t*** following, int* following_count, block_node_t* blocks)
{
	if (_is_blocked_by_active_blocks(id, blocks))
	{
		return NULL;
	}
	int index = tf_util_insert_index(id, *following, *following_count, sizeof(following_t*), _following_compare);
	following_t* entry = NULL;
	if (index < *following_count && strcmp(id, (*following)[index]->id) == 0)
	{
		entry = (*following)[index];
	}
	else
	{
		*following = tf_resize_vec(*following, sizeof(*following) * (*following_count + 1));
		if (*following_count - index)
		{
			memmove(*following + index + 1, *following + index, sizeof(following_t*) * (*following_count - index));
		}
		entry = tf_malloc(sizeof(following_t));
		(*following)[index] = entry;
		(*following_count)++;
		memset(entry, 0, sizeof(*entry));
		entry->depth = INT_MAX;
		snprintf(entry->id, sizeof(entry->id), "%s", id);
	}
	return entry;
}

static void _populate_follows_and_blocks(tf_ssb_t* ssb, following_t* entry, following_t*** following, int* following_count, block_node_t* active_blocks)
{
	sqlite3* db = tf_ssb_acquire_db_reader(ssb);
	sqlite3_stmt* statement = NULL;
	if (sqlite3_prepare(db,
			"SELECT json_extract(content, '$.contact') AS contact, json_extract(content, '$.following'), json_extract(content, '$.blocking') "
			"FROM messages "
			"WHERE contact IS NOT NULL AND author = ? AND json_extract(content, '$.type') = 'contact' "
			"ORDER BY sequence",
			-1, &statement, NULL) == SQLITE_OK)
	{
		if (sqlite3_bind_text(statement, 1, entry->id, -1, NULL) == SQLITE_OK)
		{
			while (sqlite3_step(statement) == SQLITE_ROW)
			{
				const char* contact = (const char*)sqlite3_column_text(statement, 0);
				if (sqlite3_column_type(statement, 1) != SQLITE_NULL)
				{
					bool is_following = sqlite3_column_int(statement, 1) != 0;
					following_t* next = _make_following_node(contact, following, following_count, active_blocks);
					if (next)
					{
						if (is_following)
						{
							if (_add_following_entry(&entry->following, &entry->following_count, next))
							{
								next->ref_count++;
							}
						}
						else
						{
							if (_remove_following_entry(&entry->following, &entry->following_count, next))
							{
								next->ref_count--;
							}
						}
					}
				}
				if (sqlite3_column_type(statement, 2) != SQLITE_NULL)
				{
					bool is_blocking = sqlite3_column_int(statement, 2) != 0;
					following_t* next = _make_following_node(contact, following, following_count, active_blocks);
					if (next)
					{
						if (is_blocking)
						{
							if (_add_following_entry(&entry->blocking, &entry->blocking_count, next))
							{
								next->block_ref_count++;
							}
						}
						else
						{
							if (_remove_following_entry(&entry->blocking, &entry->blocking_count, next))
							{
								next->block_ref_count--;
							}
						}
					}
				}
			}
		}
		sqlite3_finalize(statement);
	}
	tf_ssb_release_db_reader(ssb, db);
}

static void _get_following(tf_ssb_t* ssb, following_t* entry, following_t*** following, int* following_count, int depth, int max_depth, block_node_t* active_blocks)
{
	entry->depth = tf_min(depth, entry->depth);
	if (depth < max_depth && !entry->populated && !_is_blocked_by_active_blocks(entry->id, active_blocks))
	{
		entry->populated = true;
		_populate_follows_and_blocks(ssb, entry, following, following_count, active_blocks);

		if (depth < max_depth)
		{
			block_node_t blocks = { .entry = entry, .parent = active_blocks };
			for (int i = 0; i < entry->following_count; i++)
			{
				if (!_has_following_entry(entry->following[i]->id, entry->blocking, entry->blocking_count))
				{
					_get_following(ssb, entry->following[i], following, following_count, depth + 1, max_depth, &blocks);
				}
			}
		}
	}
}

tf_ssb_following_t* tf_ssb_db_following_deep(tf_ssb_t* ssb, const char** ids, int count, int depth)
{
	following_t** following = NULL;
	int following_count = 0;
	for (int i = 0; i < count; i++)
	{
		following_t* entry = _make_following_node(ids[i], &following, &following_count, NULL);
		_get_following(ssb, entry, &following, &following_count, 0, depth, NULL);
		entry->ref_count++;
	}

	int actual_following_count = 0;
	for (int i = 0; i < following_count; i++)
	{
		if (following[i]->ref_count > 0)
		{
			actual_following_count++;
		}
	}

	tf_ssb_following_t* result = tf_malloc(sizeof(tf_ssb_following_t) * (actual_following_count + 1));
	memset(result, 0, sizeof(tf_ssb_following_t) * (actual_following_count + 1));

	int write_index = 0;
	for (int i = 0; i < following_count; i++)
	{
		if (following[i]->ref_count > 0)
		{
			snprintf(result[write_index].id, sizeof(result[write_index].id), "%s", following[i]->id);
			result[write_index].following_count = following[i]->following_count;
			result[write_index].blocking_count = following[i]->blocking_count;
			result[write_index].followed_by_count = following[i]->ref_count;
			result[write_index].blocked_by_count = following[i]->block_ref_count;
			write_index++;
		}
	}

	for (int i = 0; i < following_count; i++)
	{
		tf_free(following[i]->following);
		tf_free(following[i]->blocking);
		tf_free(following[i]);
	}
	tf_free(following);

	return result;
}

const char** tf_ssb_db_following_deep_ids(tf_ssb_t* ssb, const char** ids, int count, int depth)
{
	following_t** following = NULL;
	int following_count = 0;
	for (int i = 0; i < count; i++)
	{
		following_t* entry = _make_following_node(ids[i], &following, &following_count, NULL);
		_get_following(ssb, entry, &following, &following_count, 0, depth, NULL);
		entry->ref_count++;
	}

	int actual_following_count = 0;
	for (int i = 0; i < following_count; i++)
	{
		if (following[i]->ref_count > 0)
		{
			actual_following_count++;
		}
	}

	char** result = tf_malloc(sizeof(char*) * (actual_following_count + 1) + k_id_base64_len * actual_following_count);
	char* result_ids = (char*)result + sizeof(char*) * (actual_following_count + 1);

	int write_index = 0;
	for (int i = 0; i < following_count; i++)
	{
		if (following[i]->ref_count > 0)
		{
			result[write_index] = result_ids + k_id_base64_len * write_index;
			snprintf(result[write_index], k_id_base64_len, "%s", following[i]->id);
			write_index++;
		}
	}
	result[actual_following_count] = NULL;

	for (int i = 0; i < following_count; i++)
	{
		tf_free(following[i]->following);
		tf_free(following[i]->blocking);
		tf_free(following[i]);
	}
	tf_free(following);

	return (const char**)result;
}

typedef struct _identities_t
{
	const char** ids;
	int count;
} identities_t;

static void _add_identity(const char* identity, void* user_data)
{
	identities_t* identities = user_data;
	char full_id[k_id_base64_len];
	snprintf(full_id, sizeof(full_id), "@%s", identity);
	identities->ids = tf_resize_vec(identities->ids, sizeof(const char*) * (identities->count + 1));
	identities->ids[identities->count++] = tf_strdup(full_id);
}

const char** tf_ssb_db_get_all_visible_identities(tf_ssb_t* ssb, int depth)
{
	identities_t identities = { 0 };
	tf_ssb_db_identity_visit_all(ssb, _add_identity, &identities);
	const char** following = tf_ssb_db_following_deep_ids(ssb, identities.ids, identities.count, depth);
	for (int i = 0; i < identities.count; i++)
	{
		tf_free((void*)identities.ids[i]);
	}
	tf_free(identities.ids);
	return following;
}

JSValue tf_ssb_db_get_message_by_id(tf_ssb_t* ssb, const char* id, bool is_keys)
{
	JSValue result = JS_UNDEFINED;
	JSContext* context = tf_ssb_get_context(ssb);
	sqlite3* db = tf_ssb_acquire_db_reader(ssb);
	sqlite3_stmt* statement;
	if (sqlite3_prepare(db, "SELECT previous, author, id, sequence, timestamp, hash, json(content), signature, flags FROM messages WHERE id = ?", -1, &statement, NULL) ==
		SQLITE_OK)
	{
		if (sqlite3_bind_text(statement, 1, id, -1, NULL) == SQLITE_OK)
		{
			if (sqlite3_step(statement) == SQLITE_ROW)
			{
				JSValue message = JS_UNDEFINED;
				JSValue formatted = tf_ssb_format_message(context, (const char*)sqlite3_column_text(statement, 0), (const char*)sqlite3_column_text(statement, 1),
					sqlite3_column_int64(statement, 3), sqlite3_column_double(statement, 4), (const char*)sqlite3_column_text(statement, 5),
					(const char*)sqlite3_column_text(statement, 6), (const char*)sqlite3_column_text(statement, 7), sqlite3_column_int(statement, 8));
				if (is_keys)
				{
					message = JS_NewObject(context);
					JS_SetPropertyStr(context, message, "key", JS_NewString(context, (const char*)sqlite3_column_text(statement, 2)));
					JS_SetPropertyStr(context, message, "value", formatted);
					JS_SetPropertyStr(context, message, "timestamp", JS_NewString(context, (const char*)sqlite3_column_text(statement, 4)));
				}
				else
				{
					message = formatted;
				}
				result = message;
			}
		}
		sqlite3_finalize(statement);
	}
	tf_ssb_release_db_reader(ssb, db);
	return result;
}

tf_ssb_db_stored_connection_t* tf_ssb_db_get_stored_connections(tf_ssb_t* ssb, int* out_count)
{
	sqlite3* db = tf_ssb_acquire_db_reader(ssb);
	tf_ssb_db_stored_connection_t* result = NULL;
	int count = 0;

	sqlite3_stmt* statement;
	if (sqlite3_prepare(db, "SELECT host, port, key FROM connections ORDER BY host, port, key", -1, &statement, NULL) == SQLITE_OK)
	{
		while (sqlite3_step(statement) == SQLITE_ROW)
		{
			result = tf_resize_vec(result, sizeof(tf_ssb_db_stored_connection_t) * (count + 1));
			result[count] = (tf_ssb_db_stored_connection_t) {
				.port = sqlite3_column_int(statement, 1),
			};
			snprintf(result[count].address, sizeof(result[count].address), "%s", (const char*)sqlite3_column_text(statement, 0));
			snprintf(result[count].pubkey, sizeof(result[count].pubkey), "%s", (const char*)sqlite3_column_text(statement, 2));
			count++;
		}
		sqlite3_finalize(statement);
	}
	tf_ssb_release_db_reader(ssb, db);

	*out_count = count;
	return result;
}

void tf_ssb_db_forget_stored_connection(tf_ssb_t* ssb, const char* address, int port, const char* pubkey)
{
	sqlite3* db = tf_ssb_acquire_db_writer(ssb);
	sqlite3_stmt* statement;
	if (sqlite3_prepare(db, "DELETE FROM connections WHERE host = ? AND port = ? AND key = ?", -1, &statement, NULL) == SQLITE_OK)
	{
		if (sqlite3_bind_text(statement, 1, address, -1, NULL) != SQLITE_OK || sqlite3_bind_int(statement, 2, port) != SQLITE_OK ||
			sqlite3_bind_text(statement, 3, pubkey, -1, NULL) != SQLITE_OK || sqlite3_step(statement) != SQLITE_DONE)
		{
			tf_printf("Delete stored connection: %s.\n", sqlite3_errmsg(db));
		}
		sqlite3_finalize(statement);
	}
	tf_ssb_release_db_writer(ssb, db);
}