/*! plotframes | (c) 2015 RodrigoPolo.com | MIT License | https://github.com/rodrigopolo/plotframes/blob/master/LICENSE */

var 
	fs = require('fs'),
	stream = require('stream'),
	child = require('child_process'),
	extend = require('extend'),
	path = require('path'),
	split = require("split"),
	isWin = /^win/.test(process.platform),
	defterminal = isWin ? 'windows' : 'x11';


// Average array prototype
function arrAvg(arr){
	return arr.reduce(function (p, c) {return p + c;}) / arr.length;
}

// Max array prototype
function arrMax(arr){
	return Math.max.apply(Math, arr);
}

// Min array prototype
function arrMin(arr){
	return Math.min.apply(Math, arr);
}

// Bits into human readable units
function bandWidth(bits) {
	bits = bits* 1000;
	var unit = 1000;
	if (bits < unit) return (bits % 1 === 0 ? bits : bits.toFixed(2)) + "B";
	var exp =  parseInt(Math.log(bits) / Math.log(unit));
	var pre = "KMGTPE"[exp-1] + 'bps';
	var n = bits / Math.pow(unit, exp);
	return (n % 1 === 0 ? n : n.toFixed(2))+pre;
}

// Get file Details
function getDetails(input, cb){

	var 
		rf,
		r_frame_rate = /avg_frame_rate\=(\d+)\/(\d+)/,
		frame_rate,
		rd,
		r_duration = /Duration: ((\d{2}):(\d{2}):(\d{2}).(\d{2})), /,
		duration,
		seconds;

	// Run ffprobe
	var cli = child.spawn(
		'ffprobe', [
			'-show_entries',
			'stream',
			input
		]
	);

	// Get frame rate from stdout
	cli.stdout.pipe(split()).on('data', function (data) {
		if(rf = r_frame_rate.exec(data)){
			if(!frame_rate){
				frame_rate = (rf[1]/rf[2]) || 1;
			}
		}
	});

	// Get duration from sterr
	cli.stderr.pipe(split()).on('data', function (data) {
		if(rd = r_duration.exec(data)){
			duration = rd[1];
			seconds  = ((((rd[2]*60)+rd[3])*60)+parseInt(rd[4]))+parseFloat(rd[5]/100);
		}
	});

	// After running ffprobe return the results
	cli.on('close', function (code) {
		if (code !== 0) {
			fs.exists(input, function(exists) {
				if(exists){
					cb('Error trying to get the file details.', null);
				}else{
					cb('Error trying to get the file details, input file doesn\'t exists.', null);
				}
			});
		}
		cb(null, {
			frame_rate: frame_rate,
			duration: duration,
			seconds: seconds
		});
	});

	// If node script exits, kills the child
	process.on('exit', function() {
		cli.kill();
	});

	// On error running ffprobe
	cli.on('error', function() {
		cb('Error running FFprobe, check if it is installed correctly and if it is included in the system environment path.', null);
	});
}


// Get frame bitrate
function getBitrate(input, details, progress, cb){
	var 
		// for regex
		r_frame = /(?:media_type\=(\w+)\r?\n)(?:stream_index\=(\w+)\r?\n)(?:pkt_pts_time\=(\d*.?\d*)\r?\n)(?:pkt_size\=(\d+)\r?\n)(?:pict_type\=(\w+))?/,
		r,

		// For frame arrays
		frame_count 	= 0,
		frame_stream,
		frame_type,
		frame_bitrate,
		frame_size,
		frame_time,

		// Frame Arrays
		frames = {		
			count: 		[],
			stream: 	[],
			type: 		[],
			bitrate: 	[],
			size: 		[],
			time: 		[]
		},

		// For loop
		frame_size;

	// Run ffprobe
	var cli = child.spawn(
		'ffprobe', [
			'-show_entries',
			'frame=stream_index,media_type,pict_type,pkt_size,pkt_pts_time',
			input
		]
	);

	// Get frame data
	cli.stdout.pipe(split(/\[\/FRAME\]\r?\n/)).on('data', function (data){

		if(r = r_frame.exec(data)){

			frame_count++;
			frame_stream 	= parseInt(r[2]);
			frame_type  	= r[5]?r[5]:'A';
			frame_size 		= ((r[4]*8)/1000);
			frame_bitrate	= frame_size * details.frame_rate;
			frame_time  	= parseFloat(r[3]);

			frames.count.push(frame_count);
			frames.stream.push(frame_stream);
			frames.type.push(frame_type);
			frames.bitrate.push(frame_bitrate);
			frames.size.push(frame_size);
			frames.time.push(frame_time);

			// Show progress
			progress({
				time: 		frame_time,
				duration: 	details.duration,
				length: 	details.seconds
			});
			
		}
	});

	// After running ffprobe return the results
	cli.on('close', function (code) {
		if (code !== 0) {
			cb('Error trying to get the file bitrate.', null);
		}
		cb(null, frames);

	});

	// If node script exits, kills the child
	process.on('exit', function() {
		cli.kill();
	});

	// On error running ffprobe
	cli.on('error', function() {
		cb('Error running FFprobe, check if it is installed correctly and if it is included in the system environment path.', null);
	});
}

// Create an object containing all the frame data
function getFrames(input, progress, cb){
	progress = progress || function(d){}
	getDetails(input, function(err, details){
		if(err){
			cb(err, null);
		}else{
			getBitrate(input, details, progress, function(err, data){
				if(err){
					cb(err, null);
				}else{
					cb(null, data);
				}
			});
		}
	});
}

// Generate gnuplot script
function genScript(input, frames, ops, cb){

	// Functional
	var all_streams = (ops.stream=='all');
	var is_frames = ops.frames;
	var selected_stream = parseInt(ops.stream);
	var graphs = [];
	var frame_types = [
		'I',
		'P',
		'B',
		'A',
	];
	var label_sep = '\\n';

	// for loops
	var frame_sec;

	// for storing
	var bitrate = [];
	var selected_stream_bitrate = [];
	var selected_stream_bitrate_pos = [];
	var selected_bitrate;
	var gs = '';
	var bitrate_max;
	var bitrate_min;
	var bitrate_avg;
	var selected_frame_count = 0;
	var selected_frame_types={};

	var frame_start = frames.count[0];
	var frame_end 	= frames.count[frames.count.length-1];
	var time_start 	= frames.time[0];
	var time_end 	= frames.time[frames.time.length-1];

	// Create bitrate by sec for selected streams, count frames and save frame types
	for (var i = 0; i < frames.size.length; i++) {
		frame_sec = parseInt(frames.time[i]);
		if(all_streams){
			selected_frame_types[frames.type[i]] = []; // TODO: add stream number
			selected_stream_bitrate.push(frames.size[i]);
			selected_stream_bitrate_pos.push(frames.count[i]);
			selected_frame_count++;
			if(bitrate[frame_sec]){
				bitrate[frame_sec] += frames.size[i];
			}else{
				bitrate[frame_sec] = frames.size[i];
			}
		}else{
			if(frames.stream[i] == selected_stream){
				selected_frame_types[frames.type[i]] = []; // TODO: add stream number
				selected_stream_bitrate.push(frames.size[i]);
				selected_stream_bitrate_pos.push(frames.count[i]);
				selected_frame_count++;
				if(bitrate[frame_sec]){
					bitrate[frame_sec] += frames.size[i];
				}else{
					bitrate[frame_sec] = frames.size[i];
				}
			}
		}
	};

	selected_bitrate = (is_frames)?frames.bitrate:bitrate;

	if(bitrate.length == 0){
		cb('There is no data in the selected stream.', null);
	}

	// Set font size
	gs+='set key font ",10"\n';

	// Graph range
	if(is_frames){
		gs+='set xrange ['+frame_start+':'+frame_end+']\n';
	}else{
		gs+='set xrange ['+time_start+':'+time_end+']\n';
	}

	// Title 
	gs += 'set title "Frames Bitrates for \\"'+path.basename(input);
	if(all_streams){
		gs += '\\""\n';
	}else{
		gs += ':'+ops.stream+'\\""\n';
	}

	// Measurement
	bitrate_max = arrMax(selected_bitrate);
	bitrate_min = arrMin(selected_bitrate);
	bitrate_avg = arrAvg(selected_bitrate);

	// Info label
	gs+='set label "';
	if(is_frames){
		gs+='Frames: '+selected_frame_count+' of '+frames.count[frames.count.length-1]+label_sep;
	}else{
		gs+='Seconds: '+frames.time[frames.time.length-1]+label_sep;
	}
	gs+=
	 'Max: '+bandWidth(bitrate_max)+label_sep
	+'Min: '+bandWidth(bitrate_min)+label_sep
	+'Avg: '+bandWidth(bitrate_avg);

	gs+='" left at graph 0.005, graph .970 font ",10"\n';

	// X Label
	gs+='set xlabel "'+((is_frames)?'Frames':'Seconds')+'" font ",10"\n';

	// Y Label
	gs+='set ylabel "Kbps" font ",10"\n';

	// Grid
	gs += (ops.grid)?'set grid\n':'';

	// Terminal
	gs+= 'set terminal '+ops.terminal+'\n';

	// Output
	gs += (ops.output)?'set output "'+ops.output+'"\n':'';

	// Plotting
	gs += 'plot \\\n';


	// Loop trough selected stream frames
	for (var i = 0; i < frame_types.length; i++) {
		if(selected_frame_types[frame_types[i]]){
			graphs.push('"-" title "'+frame_types[i]+'" with '+ops.styles[frame_types[i]]+' linecolor rgb "'+ops.colors[frame_types[i]]+'"');
		}
	};

	if(!is_frames){
		// Average bitrate
		graphs.push('"-" title "Average" with lines lc rgb "'+ops.colors.average+'" lt 1 lw .5');

		// Bitrate
		graphs.push('"-" smooth bezier title "Bitrate" with lines lc rgb "'+ops.colors.bitrate+'" lt 1 lw 1.5');
	}

	// Add the graphs defs			
	gs += graphs.join(', \\\n')+' \n';

	// Add frames for selected streams
	for (var i = 0; i < frames.bitrate.length; i++) {
		if(selected_frame_types[frames.type[i]]){
			if(is_frames){
				selected_frame_types[frames.type[i]].push(frames.count[i]+' '+frames.bitrate[i]);
			}else{
				selected_frame_types[frames.type[i]].push(frames.time[i]+' '+frames.bitrate[i]);
			}
		}
	};

	// Loop trough selected stream frames
	for (var i = 0; i < frame_types.length; i++) {
		if(selected_frame_types[frame_types[i]]){
			gs += selected_frame_types[frame_types[i]].join('\n')+'\ne\n';
		}
	};
	
	// Add average bitrate line
	if(!is_frames){
		gs += time_start+' '+bitrate_avg+'\n';
		gs += time_end+' '+bitrate_avg+'\ne\n';
	}

	// Add bitrate line
	if(!is_frames){
		for (var i = 0; i < bitrate.length; i++) {
			gs += i+' '+bitrate[i]+'\n';
		};
		gs += 'e';
	}

	cb(null, gs);
}

// Parse the options, gen the script and call gnuplot via stdin
function plotScript(input, cb, op){

	var options = {
		stream: 'all',
		terminal: defterminal, 
		output: false,
		frames: false,
		colors:{
			I: '#ff0000',
			P: '#00ff00',
			B: '#0000ff',
			A: '#d200ff',
			average: '#000000',
			bitrate: '#ff9016',
		},
		styles:{
			I: 'impulses',
			P: 'impulses',
			B: 'impulses',
			A: 'impulses',
		},
		grid: true,
		as_string: false,
		stdout: null,
		stderr: null,
		progress: function(d){}
	}

	extend(options, op);

	// To prevent almost imposible Command Injection
	if(options.terminal != 'windows' && options.terminal != 'x11'){
		options.terminal = defterminal;
	}

	var script_str='';

	getFrames(input, options.progress, function(err, data){
		if(err){
			cb(err, null);
		}else{
			// gnuplot script
			genScript(input, data, options,function(err, gs){

				if(err){
					cb(err, null);
				}else{
					if(options.as_string){
						cb(null, gs);
					}else{
						// Run gnuplot 
						var cli = child.spawn(
							'gnuplot', [
								'-p'
							], {stdin: 'pipe'}
						);

						// Pipe streams
						if(options.stdout){
							cli.stdout.pipe(options.stdout);
						}
						if(options.stderr){
							cli.stderr.pipe(options.stderr);
						}

						// Check if there is an error code, if not, run the callback with true message
						cli.on('close', function (code) {
							if (code !== 0) {
								cb('Error trying to run gnuplot.', null);
							}else{
								cb(null, true);
							}
						});

						// If node script exits, kills the child
						process.on('exit', function() {
							cli.kill();
						});

						// On error running gnuplot
						cli.on('error', function() {
							cb('Error running gnuplot, check if it is installed correctly and if it is included in the system environment path.', null);
						});

						cli.stdin.setEncoding('utf-8');

						var script = new stream.Readable();
						script._read = function noop() {};

						script.pipe(cli.stdin);

						script.push(gs);
						script.push(null);
					}
				}
			});
		}
	}, options);
}

module.exports = {
	getFrames: getFrames,
	plotScript: plotScript
};