#include "file.js.h"

#include "task.h"

#include <malloc.h>
#include <stdbool.h>
#include <uv.h>

#ifdef _WIN32
#include <windows.h>
#else
#include <dirent.h>
#include <unistd.h>
#endif

static JSValue _file_make_directory(JSContext* context, JSValueConst this_val, int argc, JSValueConst* argv);
static JSValue _file_read_directory(JSContext* context, JSValueConst this_val, int argc, JSValueConst* argv);
static JSValue _file_read_file(JSContext* context, JSValueConst this_val, int argc, JSValueConst* argv);
static JSValue _file_rename_file(JSContext* context, JSValueConst this_val, int argc, JSValueConst* argv);
static JSValue _file_stat(JSContext* context, JSValueConst this_val, int argc, JSValueConst* argv);
static JSValue _file_unlink_file(JSContext* context, JSValueConst this_val, int argc, JSValueConst* argv);
static JSValue _file_write_file(JSContext* context, JSValueConst this_val, int argc, JSValueConst* argv);

static double _time_spec_to_double(const uv_timespec_t* time_spec);
static void _file_on_stat_complete(uv_fs_t* request);

typedef struct file_stat_t {
	void* _task;
	JSContext* _context;
	promiseid_t _promise;
	uv_fs_t _request;
} file_stat_t;

void tf_file_register(JSContext* context)
{
	JSValue global = JS_GetGlobalObject(context);
	JSValue file = JS_NewObject(context);
	JS_SetPropertyStr(context, global, "File", file);
	JS_SetPropertyStr(context, file, "makeDirectory", JS_NewCFunction(context, _file_make_directory, "makeDirectory", 1));
	JS_SetPropertyStr(context, file, "readDirectory", JS_NewCFunction(context, _file_read_directory, "readDirectory", 1));
	JS_SetPropertyStr(context, file, "readFile", JS_NewCFunction(context, _file_read_file, "readFile", 1));
	JS_SetPropertyStr(context, file, "renameFile", JS_NewCFunction(context, _file_rename_file, "renameFile", 2));
	JS_SetPropertyStr(context, file, "stat", JS_NewCFunction(context, _file_stat, "stat", 1));
	JS_SetPropertyStr(context, file, "unlinkFile", JS_NewCFunction(context, _file_unlink_file, "unlinkFile", 1));
	JS_SetPropertyStr(context, file, "writeFile", JS_NewCFunction(context, _file_write_file, "writeFile", 2));
	JS_FreeValue(context, global);
}

static const int k_file_read_max = 4 * 1024 * 1024;

static void _file_read_close_callback(uv_fs_t* req)
{
	uv_fs_req_cleanup(req);
	free(req);
}

static void _file_read_read_callback(uv_fs_t* req)
{
	uv_fs_req_cleanup(req);
	tf_task_t* task = req->loop->data;
	JSContext* context = tf_task_get_context(task);
	promiseid_t promise = (promiseid_t)(intptr_t)req->data;
	if (req->result >= 0)
	{
		JSValue arrayBuffer = JS_NewArrayBufferCopy(context, (uint8_t*)(req + 1), req->result);
		JSValue global = JS_GetGlobalObject(context);
		JSValue constructor = JS_GetPropertyStr(context, global, "Uint8Array");
		JSValue typedArray = JS_CallConstructor(context, constructor, 1, &arrayBuffer);
		JS_FreeValue(context, constructor);
		JS_FreeValue(context, global);
		JS_FreeValue(context, arrayBuffer);
		tf_task_resolve_promise(task, promise, typedArray);
		JS_FreeValue(context, typedArray);
	}
	else
	{
		tf_task_reject_promise(task, promise, JS_ThrowInternalError(context, uv_strerror(req->result)));
	}
	int result = uv_fs_close(req->loop, req, req->file, _file_read_close_callback);
	if (result < 0)
	{
		free(req);
	}
}

static void _file_read_open_callback(uv_fs_t* req)
{
	uv_fs_req_cleanup(req);
	tf_task_t* task = req->loop->data;
	JSContext* context = tf_task_get_context(task);
	promiseid_t promise = (promiseid_t)(intptr_t)req->data;
	if (req->result >= 0)
	{
		uv_buf_t buf = { .base = (char*)(req + 1), .len = k_file_read_max };
		uv_file file = req->result;
		int result = uv_fs_read(req->loop, req, file, &buf, 1, 0, _file_read_read_callback);
		if (result < 0)
		{
			tf_task_reject_promise(task, promise, JS_ThrowInternalError(context, uv_strerror(result)));
			result = uv_fs_close(req->loop, req, file, _file_read_close_callback);
		}
	}
	else
	{
		tf_task_reject_promise(task, promise, JS_ThrowInternalError(context, uv_strerror(req->result)));
		free(req);
	}
}

static JSValue _file_read_file(JSContext* context, JSValueConst this_val, int argc, JSValueConst* argv)
{
	void* task = JS_GetContextOpaque(context);
	const char* file_name = JS_ToCString(context, argv[0]);

	promiseid_t promise = tf_task_allocate_promise(task);
	uv_fs_t* req = malloc(sizeof(uv_fs_t) + k_file_read_max);
	*req = (uv_fs_t)
	{
		.data = (void*)(intptr_t)promise,
	};
	int result = uv_fs_open(tf_task_get_loop(task), req, file_name, UV_FS_O_RDONLY, 0, _file_read_open_callback);
	if (result < 0)
	{
		tf_task_reject_promise(task, promise, JS_ThrowInternalError(context, uv_strerror(result)));
	}
	JS_FreeCString(context, file_name);
	return tf_task_get_promise(task, promise);
}

static JSValue _file_write_file(JSContext* context, JSValueConst this_val, int argc, JSValueConst* argv)
{
	JSValue result = JS_NULL;
	const char* fileName = JS_ToCString(context, argv[0]);
	FILE* file = fopen(fileName, "wb");
	JS_FreeCString(context, fileName);

	if (file)
	{
		size_t size;
		uint8_t* buffer = tf_try_get_array_buffer(context, &size, argv[1]);
		if (buffer)
		{
			int written = fwrite((const char*)buffer, 1, size, file);
			result = JS_NewInt32(context, (size_t)written == size ? 0 : written);
		}
		else
		{
			const char* data = JS_ToCStringLen(context, &size, argv[1]);
			int written = fwrite((const char*)data, 1, size, file);
			result = JS_NewInt32(context, (size_t)written == size ? 0 : written);
			JS_FreeCString(context, data);
		}
		fclose(file);
	}
	return result;
}

static JSValue _file_rename_file(JSContext* context, JSValueConst this_val, int argc, JSValueConst* argv)
{
	void* task = JS_GetContextOpaque(context);
	const char* oldName = JS_ToCString(context, argv[0]);
	const char* newName = JS_ToCString(context, argv[1]);
	uv_fs_t req;
	int result = uv_fs_rename(tf_task_get_loop(task), &req, oldName, newName, 0);
	JS_FreeCString(context, oldName);
	JS_FreeCString(context, newName);
	return JS_NewInt32(context, result);
}

static JSValue _file_unlink_file(JSContext* context, JSValueConst this_val, int argc, JSValueConst* argv)
{
	void* task = JS_GetContextOpaque(context);
	const char* fileName = JS_ToCString(context, argv[0]);
	uv_fs_t req;
	int result = uv_fs_unlink(tf_task_get_loop(task), &req, fileName, 0);
	JS_FreeCString(context, fileName);
	return JS_NewInt32(context, result);
}

static JSValue _file_read_directory(JSContext* context, JSValueConst this_val, int argc, JSValueConst* argv)
{
	const char* directory = JS_ToCString(context, argv[0]);
	JSValue array = JS_NewArray(context);

#ifdef _WIN32
	WIN32_FIND_DATA find;
	std::string pattern = directory;
	pattern += "\\*";
	HANDLE handle = FindFirstFile(pattern.c_str(), &find);
	if (handle != INVALID_HANDLE_VALUE)
	{
		int index = 0;
		do {
			JS_SetPropertyUint32(context, array, index++, JS_NewString(context, find.cFileName));
		} while (FindNextFile(handle, &find) != 0);
		FindClose(handle);
	}
#else
	DIR* dir = opendir(directory);
	if (dir)
	{
		uint32_t index = 0;
		struct dirent* entry = readdir(dir);
		while (entry)
		{
			JS_SetPropertyUint32(context, array, index++, JS_NewString(context, entry->d_name));
			entry = readdir(dir);
		}
		closedir(dir);
	}
#endif

	JS_FreeCString(context, directory);
	return array;
}

JSValue _file_make_directory(JSContext* context, JSValueConst this_val, int argc, JSValueConst* argv)
{
	void* task = JS_GetContextOpaque(context);
	const char* directory = JS_ToCString(context, argv[0]);

	uv_fs_t req;
	int result = uv_fs_mkdir(tf_task_get_loop(task), &req, directory, 0755, 0);
	JS_FreeCString(context, directory);
	return JS_NewInt32(context, result);
}

JSValue _file_stat(JSContext* context, JSValueConst this_val, int argc, JSValueConst* argv)
{
	void* task = JS_GetContextOpaque(context);
	const char* path = JS_ToCString(context, argv[0]);
	promiseid_t promise = tf_task_allocate_promise(task);

	file_stat_t* data = malloc(sizeof(file_stat_t));
	data->_task = task;
	data->_promise = promise;
	data->_request.data = data;
	data->_context = context;

	int result = uv_fs_stat(tf_task_get_loop(task), &data->_request, path, _file_on_stat_complete);
	if (result)
	{
		tf_task_reject_promise(task, promise, JS_NewInt32(context, result));
		free(data);
	}
	JS_FreeCString(context, path);
	return tf_task_get_promise(task, promise);
}

static double _time_spec_to_double(const uv_timespec_t* time_spec)
{
	return time_spec->tv_sec + (double)(time_spec->tv_nsec) / 1e9;
}

static void _file_on_stat_complete(uv_fs_t* request)
{
	file_stat_t* data = (file_stat_t*)(request->data);
	JSContext* context = data->_context;

	if (request->result)
	{
		tf_task_reject_promise(data->_task, data->_promise, JS_NewInt32(context, request->result));
	}
	else
	{
		JSValue result = JS_NewObject(context);
		JS_SetPropertyStr(context, result, "mtime", JS_NewFloat64(context, _time_spec_to_double(&request->statbuf.st_mtim)));
		JS_SetPropertyStr(context, result, "ctime", JS_NewFloat64(context, _time_spec_to_double(&request->statbuf.st_ctim)));
		JS_SetPropertyStr(context, result, "atime", JS_NewFloat64(context, _time_spec_to_double(&request->statbuf.st_atim)));
		JS_SetPropertyStr(context, result, "size", JS_NewFloat64(context, request->statbuf.st_size));
		tf_task_resolve_promise(data->_task, data->_promise, result);
		JS_FreeValue(context, result);
	}
	uv_fs_req_cleanup(request);
	free(data);
}