#include <string.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include "edl.h"

#define strnchr(haystack, needle, length) memchr(haystack, needle, strnlen(haystack, length))

static uint32_t EDL_internal_crcn32b(const unsigned char* restrict message, size_t length) {
	uint32_t crc = 0xFFFFFFFF;

	size_t i;
	for (i = 0; i < length && message[i]; i++) {
		crc = crc ^ message[i];
		size_t j;
		for (j = 0; j < 8; j++)
			crc = (crc >> 1) ^ (0xEDB88320 & -(crc & 1));
	}

	return ~crc;
}

/* This parses the first line of the EDL and
 * creates an array with CRC32 hashes in
 * the order of the strings.
*/
static uint32_t* EDL_internal_parse_first_line(const char* data, size_t* restrict length) {
	size_t hashes_size = 32, current_hash = 0;
	uint32_t* hashes = malloc(hashes_size * sizeof(uint32_t));

	size_t len_until_newline = strchr(data, '\n') - data, i, b;
	for (i = 0, b = 0; i < len_until_newline; i++, b++) {
		if (data[i] == ';') {
			if (current_hash >= hashes_size)
				hashes = realloc(hashes, (hashes_size *= 2) * sizeof(uint32_t));
			hashes[current_hash++] = EDL_internal_crcn32b((const unsigned char*)&data[i - b], b);
			b = -1; // ew
		}
	}

	*length = current_hash;

	return hashes;
}

/* -- Functions to extract different datatypes -- */

static size_t EDL_internal_append_offset(const char* input, size_t offset, size_t length) {
	size_t s = 0;

	s += strchr(&input[offset + s], ';') - &input[offset];
	if (s + offset > length)
		return s;

	s += strspn(&input[offset + s], ";\t ");
	if (s + offset > length)
		return s;

	return s;
}

static size_t EDL_internal_get_int(const char* input, size_t offset, size_t length, int* int_return) {
	if (offset > length)
		return 0;

	{
		char* ptr_return;
		*int_return = strtol(&input[offset], &ptr_return, 10);

		if (!ptr_return)
			return 0;
	}

	return EDL_internal_append_offset(input, offset, length);
}

static size_t EDL_internal_get_double(const char* input, size_t offset, size_t length, double* double_return) {
	if (offset > length)
		return 0;

	{
		char* ptr_return;
		*double_return = strtod(&input[offset], &ptr_return);

		if (!ptr_return)
			return 0;
	}

	return EDL_internal_append_offset(input, offset, length);
}

static size_t EDL_internal_get_bool(const char* input, size_t offset, size_t length, bool* bool_return) {
	if (offset > length)
		return 0;

	if (strncmp((input + offset), "TRUE", 4))
		*bool_return = true;
	else if (strncmp((input + offset), "FALSE", 5))
		*bool_return = false;

	return EDL_internal_append_offset(input, offset, length);
}

static size_t EDL_internal_get_media_type(const char* input, size_t offset, size_t length, MediaType* media_return) {
	if (offset > length)
		return 0;

	if (strncmp(input + offset, "VIDEO", 5))
		*media_return = MEDIATYPE_VIDEO;
	else if (strncmp(input + offset, "AUDIO", 5))
		*media_return = MEDIATYPE_AUDIO;

	return EDL_internal_append_offset(input, offset, length);
}

static size_t EDL_internal_get_string(const char* input, size_t offset, size_t length, char** string_return) {
	/* Windows filenames will *NEVER* include double quotes.
	   This might break with EDL files created with Reaper on Linux. */
	if (offset > length)
		return 0;

	size_t start = strchr(&input[offset], '\"') - &input[offset] + 1;
	if (start + offset > length)
		return 0;

	size_t s_length = strchr(&input[offset + start], '\"') - &input[offset] - start;
	if (start + s_length + offset > length)
		return 0;

	*string_return = malloc((s_length + 1) * sizeof(char));
	if (!*string_return)
		return 0;

	memcpy(*string_return, &input[offset + start], s_length);
	(*string_return)[s_length] = '\0';

	return EDL_internal_append_offset(input, offset, length);
}

/* memory management routines */

static int EDL_internal_reallocate(EDL_file* input, size_t new_capacity) {
	input->arr = realloc(input->arr, new_capacity * sizeof(EDL_line));
	if (!input->arr)
		return 0;

	if (new_capacity > input->capacity)
		memset(input->arr + input->capacity, 0, new_capacity - input->capacity);

	input->capacity = new_capacity;

	return 1;
}

static int EDL_internal_allocate_memory(EDL_file* input) {
	return EDL_internal_reallocate(input, input->capacity ? input->capacity * 2 : 16);
}

static int EDL_internal_shrink_memory_to_fit(EDL_file* input) {
	return EDL_internal_reallocate(input, input->size);
}

/* the important function */
EDL_file EDL_parse(const char* data, size_t length) {
	EDL_file edl = {0};
	if (!EDL_internal_allocate_memory(&edl))
		return edl;

	size_t order_size = 0;
	uint32_t* order = EDL_internal_parse_first_line(data, &order_size);

	size_t offset = 0;
	while ((offset = strnchr(data + offset + 1, '\n', length - offset) - (void*)data) < length) {
		size_t local_offset = offset; // this is so our original offset stays intact

		bool ok = true;

		for (int i = 0; i < order_size; i++) {
#define ADD_TO_OFFSET(x, a) \
{ \
	size_t o = a(data, local_offset, length, &edl.arr[edl.size].x); \
	if (!o) \
		ok = false; \
	local_offset += o; \
}
			switch (order[i]) {
				case 0x1541c503: /* ID */
					ADD_TO_OFFSET(id, EDL_internal_get_int);
					break;
				case 0x4b211812: /* Track */
					ADD_TO_OFFSET(track, EDL_internal_get_int);
					break;
				case 0xbb46516f: /* StartTime */
					ADD_TO_OFFSET(start_time, EDL_internal_get_double);
					break;
				case 0xaeac5df7: /* Length */
					ADD_TO_OFFSET(length, EDL_internal_get_double);
					break;
				case 0x03834606: /* PlayRate */
					ADD_TO_OFFSET(play_rate, EDL_internal_get_double);
					break;
				case 0x0c2083d3: /* Locked */
					ADD_TO_OFFSET(locked, EDL_internal_get_bool);
					break;
				case 0xe60c8b1d: /* Normalized */
					ADD_TO_OFFSET(normalized, EDL_internal_get_bool);
					break;
				case 0xbe5802c9: /* StretchMethod */
					ADD_TO_OFFSET(stretch_method, EDL_internal_get_int);
					break;
				case 0x4ec8be4c: /* Looped */
					ADD_TO_OFFSET(looped, EDL_internal_get_bool);
					break;
				case 0xe6cb84d1: /* OnRuler */
					ADD_TO_OFFSET(on_ruler, EDL_internal_get_bool);
					break;
				case 0x035f84c2: /* MediaType */
					ADD_TO_OFFSET(media_type, EDL_internal_get_media_type);
					break;
				case 0x379d32c5: /* FileName */
					ADD_TO_OFFSET(filename, EDL_internal_get_string);
					break;
				case 0x9f334738: /* Stream */
					ADD_TO_OFFSET(stream, EDL_internal_get_int);
					break;
				case 0x07b4e0e7: /* StreamStart */
					ADD_TO_OFFSET(stream_start, EDL_internal_get_double);
					break;
				case 0x8f16c7b8: /* StreamLength */
					ADD_TO_OFFSET(stream_length, EDL_internal_get_double);
					break;
				case 0xd2edd7e4: /* FadeTimeIn */
					ADD_TO_OFFSET(fade_time_in, EDL_internal_get_double);
					break;
				case 0x792e8c40: /* FadeTimeOut */
					ADD_TO_OFFSET(fade_time_out, EDL_internal_get_double);
					break;
				case 0x98374657: /* SustainGain */
					ADD_TO_OFFSET(sustain_gain, EDL_internal_get_double);
					break;
				case 0x3e998b1f: /* CurveIn */
					ADD_TO_OFFSET(curve_in, EDL_internal_get_int);
					break;
				case 0x82fb09c4: /* GainIn */
					ADD_TO_OFFSET(gain_in, EDL_internal_get_double);
					break;
				case 0x53add388: /* CurveOut */
					ADD_TO_OFFSET(curve_out, EDL_internal_get_int);
					break;
				case 0x4210ba56: /* GainOut */
					ADD_TO_OFFSET(gain_out, EDL_internal_get_double);
					break;
				case 0x89c4df6c: /* Layer */
					ADD_TO_OFFSET(layer, EDL_internal_get_int);
					break;
				case 0xadf2f1a3: /* Color */
					ADD_TO_OFFSET(color, EDL_internal_get_int);
					break;
				case 0xa56b43e1: /* CurveInR */
					ADD_TO_OFFSET(curve_in_r, EDL_internal_get_int);
					break;
				case 0xcb6d715e: /* CurveOutR */
					ADD_TO_OFFSET(curve_out_r, EDL_internal_get_int);
					break;
				case 0x9da1b9ed: /* PlayPitch */
					ADD_TO_OFFSET(play_pitch, EDL_internal_get_double);
					break;
				case 0x2bda6ed4: /* LockPitch */
					ADD_TO_OFFSET(lock_pitch, EDL_internal_get_bool);
					break;
				case 0x3071a4c6: /* FirstChannel */
					ADD_TO_OFFSET(first_channel, EDL_internal_get_int);
					break;
				case 0x7de1bd40: /* Channels */
					ADD_TO_OFFSET(channels, EDL_internal_get_int);
					break;
				default:
					/* ... what */
					break;
			}
		}

		if (!ok)
			break;

		if (++edl.size >= edl.capacity)
			EDL_internal_allocate_memory(&edl);
	}

	EDL_internal_shrink_memory_to_fit(&edl);

	free(order);

	return edl;
}

void EDL_free(EDL_file file) {
	size_t i;
	for (i = 0; i < file.size; i++) {
		if (file.arr[i].filename)
			free(file.arr[i].filename);
	}
	free(file.arr);
}