// Copyright (c) 2015 YamaArashi

#include <stdio.h>
#include <string.h>
#include "global.h"
#include "gfx.h"
#include "util.h"

// Read/write Paint Shop Pro palette files.

// Format of a Paint Shop Pro palette file, line by line:
// "JASC-PAL\r\n" (signature)
// "0100\r\n" (version; seems to always be "0100")
// "<NUMBER_OF_COLORS>\r\n" (number of colors in decimal)
//
// 16 or 256 times (depending on above line):
// "<RED> <GREEN> <BLUE>\r\n" (color entry)
//
// Each color component is a decimal number from 0 to 255.
// Examples:
// Black - "0 0 0\r\n"
// Blue  - "0 0 255\r\n"
// Brown - "150 75 0\r\n"

#define MAX_LINE_LENGTH 11

void ReadJascPaletteLine(FILE *fp, char *line)
{
	int c;
	int length = 0;

	for (;;) {
		c = fgetc(fp);

		if (c == '\r') {
			c = fgetc(fp);

			if (c != '\n')
				FATAL_ERROR("CR line endings aren't supported.\n");

			line[length] = 0;

			return;
		}

		if (c == '\n')
			FATAL_ERROR("LF line endings aren't supported.\n");

		if (c == EOF)
			FATAL_ERROR("Unexpected EOF. No CRLF at end of file.\n");

		if (c == 0)
			FATAL_ERROR("NUL character in file.\n");

		if (length == MAX_LINE_LENGTH) {
			line[length] = 0;
			FATAL_ERROR("The line \"%s\" is too long.\n", line);
		}

		line[length++] = c;
	}
}

void ReadJascPalette(char *path, struct Palette *palette)
{
	char line[MAX_LINE_LENGTH + 1];

	FILE *fp = fopen(path, "rb");

	ReadJascPaletteLine(fp, line);

	if (strcmp(line, "JASC-PAL") != 0)
		FATAL_ERROR("Invalid JASC-PAL signature.\n");

	ReadJascPaletteLine(fp, line);

	if (strcmp(line, "0100") != 0)
		FATAL_ERROR("Unsuported JASC-PAL version.\n");

	ReadJascPaletteLine(fp, line);

	if (!ParseNumber(line, NULL, 10, &palette->numColors))
		FATAL_ERROR("Failed to parse number of colors.\n");

	if (palette->numColors != 16 && palette->numColors != 256)
		FATAL_ERROR("%d is an invalid number of colors. The number of colors must be 16 or 256.\n", palette->numColors);

	for (int i = 0; i < palette->numColors; i++) {
		ReadJascPaletteLine(fp, line);

		char *s = line;
		char *end;

		int red;
		int green;
		int blue;

		if (!ParseNumber(s, &end, 10, &red))
			FATAL_ERROR("Failed to parse red color component.\n");

		s = end;

		if (*s != ' ')
			FATAL_ERROR("Expected a space after red color component.\n");

		s++;

		if (*s < '0' || *s > '9')
			FATAL_ERROR("Expected only a space between red and green color components.\n");

		if (!ParseNumber(s, &end, 10, &green))
			FATAL_ERROR("Failed to parse green color component.\n");

		s = end;

		if (*s != ' ')
			FATAL_ERROR("Expected a space after green color component.\n");

		s++;

		if (*s < '0' || *s > '9')
			FATAL_ERROR("Expected only a space between green and blue color components.\n");

		if (!ParseNumber(s, &end, 10, &blue))
			FATAL_ERROR("Failed to parse blue color component.\n");

		if (*end != 0)
			FATAL_ERROR("Garbage after blue color component.\n");

		if (red < 0 || red > 255)
			FATAL_ERROR("Red color component (%d) is outside the range [0, 255].\n", red);

		if (green < 0 || green > 255)
			FATAL_ERROR("Green color component (%d) is outside the range [0, 255].\n", green);

		if (blue < 0 || blue > 255)
			FATAL_ERROR("Blue color component (%d) is outside the range [0, 255].\n", blue);

		palette->colors[i].red = red;
		palette->colors[i].green = green;
		palette->colors[i].blue = blue;
	}

	if (fgetc(fp) != EOF)
		FATAL_ERROR("Garbage after color data.\n");

	fclose(fp);
}

void WriteJascPalette(char *path, struct Palette *palette)
{
	FILE *fp = fopen(path, "wb");

	fputs("JASC-PAL\r\n", fp);
	fputs("0100\r\n", fp);
	fprintf(fp, "%d\r\n", palette->numColors);

	for (int i = 0; i < palette->numColors; i++) {
		struct Color *color = &palette->colors[i];
		fprintf(fp, "%d %d %d\r\n", color->red, color->green, color->blue);
	}

	fclose(fp);
}