/* jslint node: true */
'use strict';

const Errors		= require('./enig_error.js').Errors;

//	deps
const iconv			= require('iconv-lite');
const { Parser }	= require('binary-parser');

exports.readSAUCE		= readSAUCE;

const SAUCE_SIZE	= 128;
const SAUCE_ID		= new Buffer([0x53, 0x41, 0x55, 0x43, 0x45]);	//	'SAUCE'

//	:TODO read comments
//const COMNT_ID		= new Buffer([0x43, 0x4f, 0x4d, 0x4e, 0x54]);	//	'COMNT'

exports.SAUCE_SIZE		= SAUCE_SIZE;
//	:TODO: SAUCE should be a class
//	- with getFontName()
//	- ...other methods

//
//	See
//	http://www.acid.org/info/sauce/sauce.htm
//
const SAUCE_VALID_DATA_TYPES = [0, 1, 2, 3, 4, 5, 6, 7, 8 ];

function readSAUCE(data, cb) {
	if(data.length < SAUCE_SIZE) {
		return cb(Errors.DoesNotExist('No SAUCE record present'));
	}

	let sauceRec;
	try {
		sauceRec = new Parser()
			.buffer('id', { length : 5 } )
			.buffer('version', { length : 2 } )
			.buffer('title', { length: 35 } )
			.buffer('author', { length : 20 } )
			.buffer('group', { length: 20 } )
			.buffer('date', { length: 8 } )
			.uint32le('fileSize')
			.int8('dataType')
			.int8('fileType')
			.uint16le('tinfo1')
			.uint16le('tinfo2')
			.uint16le('tinfo3')
			.uint16le('tinfo4')
			.int8('numComments')
			.int8('flags')
			//	:TODO: does this need to be optional?
			.buffer('tinfos', { length: 22 } )	//	SAUCE 00.5
			.parse(data.slice(data.length - SAUCE_SIZE));
	} catch(e) {
		return cb(Errors.Invalid('Invalid SAUCE record'));
	}


	if(!SAUCE_ID.equals(sauceRec.id)) {
		return cb(Errors.DoesNotExist('No SAUCE record present'));
	}

	const ver = iconv.decode(sauceRec.version, 'cp437');

	if('00' !== ver) {
		return cb(Errors.Invalid(`Unsupported SAUCE version: ${ver}`));
	}

	if(-1 === SAUCE_VALID_DATA_TYPES.indexOf(sauceRec.dataType)) {
		return cb(Errors.Invalid(`Unsupported SAUCE DataType: ${sauceRec.dataType}`));
	}

	const sauce = {
		id 			: iconv.decode(sauceRec.id, 'cp437'),
		version		: iconv.decode(sauceRec.version, 'cp437').trim(),
		title		: iconv.decode(sauceRec.title, 'cp437').trim(),
		author		: iconv.decode(sauceRec.author, 'cp437').trim(),
		group		: iconv.decode(sauceRec.group, 'cp437').trim(),
		date		: iconv.decode(sauceRec.date, 'cp437').trim(),
		fileSize	: sauceRec.fileSize,
		dataType	: sauceRec.dataType,
		fileType	: sauceRec.fileType,
		tinfo1		: sauceRec.tinfo1,
		tinfo2		: sauceRec.tinfo2,
		tinfo3		: sauceRec.tinfo3,
		tinfo4		: sauceRec.tinfo4,
		numComments	: sauceRec.numComments,
		flags		: sauceRec.flags,
		tinfos		: sauceRec.tinfos,
	};

	const dt = SAUCE_DATA_TYPES[sauce.dataType];
	if(dt && dt.parser) {
		sauce[dt.name] = dt.parser(sauce);
	}

	return cb(null, sauce);
}

//	:TODO: These need completed:
const SAUCE_DATA_TYPES = {
	0	: { name : 'None' },
	1	: { name : 'Character', parser : parseCharacterSAUCE },
	2 	: 'Bitmap',
	3	: 'Vector',
	4	: 'Audio',
	5	: 'BinaryText',
	6	: 'XBin',
	7	: 'Archive',
	8	: 'Executable',
};

const SAUCE_CHARACTER_FILE_TYPES = {
	0	: 'ASCII',
	1	: 'ANSi',
	2	: 'ANSiMation',
	3	: 'RIP script',
	4	: 'PCBoard',
	5	: 'Avatar',
	6	: 'HTML',
	7	: 'Source',
	8	: 'TundraDraw',
};

//
//	Map of SAUCE font -> encoding hint
//
//	Note that this is the same mapping that x84 uses. Be compatible!
//
const SAUCE_FONT_TO_ENCODING_HINT = {
	'Amiga MicroKnight'		: 'amiga',
	'Amiga MicroKnight+'	: 'amiga',
	'Amiga mOsOul'			: 'amiga',
	'Amiga P0T-NOoDLE'		: 'amiga',
	'Amiga Topaz 1'			: 'amiga',
	'Amiga Topaz 1+'		: 'amiga',
	'Amiga Topaz 2'			: 'amiga',
	'Amiga Topaz 2+'		: 'amiga',
	'Atari ATASCII'			: 'atari',
	'IBM EGA43'				: 'cp437',
	'IBM EGA'				: 'cp437',
	'IBM VGA25G'			: 'cp437',
	'IBM VGA50'				: 'cp437',
	'IBM VGA'				: 'cp437',
};

[
	'437', '720', '737', '775', '819', '850', '852', '855', '857', '858',
	'860', '861', '862', '863', '864', '865', '866', '869', '872'
].forEach( page => {
	const codec = 'cp' + page;
	SAUCE_FONT_TO_ENCODING_HINT['IBM EGA43 ' + page]	= codec;
	SAUCE_FONT_TO_ENCODING_HINT['IBM EGA ' + page]		= codec;
	SAUCE_FONT_TO_ENCODING_HINT['IBM VGA25g ' + page]	= codec;
	SAUCE_FONT_TO_ENCODING_HINT['IBM VGA50 ' + page]	= codec;
	SAUCE_FONT_TO_ENCODING_HINT['IBM VGA ' + page]		= codec;
});

function parseCharacterSAUCE(sauce) {
	const result = {};

	result.fileType	= SAUCE_CHARACTER_FILE_TYPES[sauce.fileType] || 'Unknown';

	if(sauce.fileType === 0 || sauce.fileType === 1 || sauce.fileType === 2) {
		//	convience: create ansiFlags
		sauce.ansiFlags = sauce.flags;

		let i = 0;
		while(i < sauce.tinfos.length && sauce.tinfos[i] !== 0x00) {
			++i;
		}

		const fontName = iconv.decode(sauce.tinfos.slice(0, i), 'cp437');
		if(fontName.length > 0) {
			result.fontName = fontName;
		}
	}

	return result;
}