#!/usr/bin/env node

/* eslint-disable no-process-exit */
"use strict";

var hlsdump = require('commander');
hlsdump.version('0.0.0')
   .usage('[options] <url>')
   .option('-o, --output <path>', 'target file')
   .option('-u, --udp [host:port]', 'relay TS over UDP', function(val) {
     var r = { host: 'localhost', port: 1234 };
     if (val) {
       var s = val.split(':');
       if (s.length === 1) {
         r.port = parseInt(s[0], 10);
       } else {
         r.host = s[0];
         r.port = parseInt(s[1], 10);
       }
     }
     return r;
   })
   .option('-b, --buffer-size <bytes>|full', 'try to buffer <bytes> of input data (implies -s)', function(val) {
     if (val === 'full') return 0x80000000 - 1;
     return parseInt(val, 0);
   })
   .option('-s, --sync', 'clock sync using stream PCR')
   .option('-f, --full-stream', 'fetch all stream data')
   .option('-c, --concurrent <count>', 'fetch using concurrent connections', parseInt)
   .option('-a, --user-agent <string>', 'HTTP User-Agent')
   .option('-i, --info-port <port>', 'report status using HTTP + json', parseInt)
   .option('--cookie <data>', 'add cookie header to key requests')
   .option('--key <hex>', 'use oob key for decrypting segments', function(opt) {return new Buffer(opt, 'hex');})
   .parse(process.argv);

var url = require('url'),
    fs = require('fs'),
    http = require('http'),
    crypto = require('crypto');

var streamprocess = require('streamprocess'),
    oncemore = require('oncemore'),
    uristream = require('uristream'),
    HlsSegmentReader = require('hls-segment-reader'),
    UdpBlast = require('udp-blast');
var tssmooth = require('../lib/tssmooth');

var Passthrough = require('readable-stream/passthrough');

var stats = require('measured').createCollection();

var src = hlsdump.args[0];
if (!src) {
  hlsdump.help();
  process.exit(-1);
}

if (hlsdump.bufferSize) hlsdump.sync = true;

var r = new HlsSegmentReader(src, {highWaterMark:(hlsdump.concurrent || 1) - 1, fullStream:hlsdump.fullStream});

var totalDuration = 0, currentSegment = -1;
var reading = false, hooked = false;
var keyCache = {};

streamprocess(r, function (obj, done) {
  var meta = obj.meta;
  var duration = obj.segment.duration;
  var downloadSize = meta.size;
  var stream = oncemore(obj.stream);
  totalDuration += duration;

  console.error('piping segment', meta.url);

  var stopwatch = stats.timer('fetchTime').start();
  stream.once('close', 'end', 'error', function() {
    stopwatch.end();
  });

  reading = true;
  currentSegment = obj.seq;

  // calculate size when missing
  if (downloadSize === -1) {
    downloadSize = 0;
    obj.stream.on('data', function(chunk) {
      downloadSize += chunk.length;
    });
  }

  var keyData = obj.segment.key;
  if (keyData && keyData.method === 'AES-128' && keyData.uri && keyData.uri.length > 2) {
    fetchKey(function(err, key) {
      if (err) {
        console.error('key fetch failed:', err);
        return pushBuffer(stream);
      }
      var iv = new Buffer(keyData.iv.slice(-32), 'hex');
      try {
        var decrypt = crypto.createDecipheriv('aes-128-cbc', key, iv);
      } catch (ex) {
        console.error('crypto setup failed:', ex.stack || ex);
        return pushBuffer(stream);
      }

      stream.on('error', function(err) {
        decrypt.emit('error', err);
      });
      pushBuffer(oncemore(stream.pipe(decrypt)));
    });
  } else {
    pushBuffer(stream);
  }

  function fetchKey(cb) {
    if (hlsdump.key) return cb(null, hlsdump.key);

    var uri = url.resolve(r.url, keyData.uri.slice(1,-1));
    var entry = keyCache[uri];
    if (entry && entry.length) return cb(null, keyCache[uri]);

    var key = new Buffer(0);
    var headers = {};
    if (hlsdump.cookie)
      headers.Cookie = hlsdump.cookie;

    oncemore(uristream(uri, { headers:headers, whitelist:['http', 'https', 'data'], timeout: 10 * 1000 }))
      .on('data', function(chunk) {
        key = Buffer.concat([key, chunk]);
      })
      .once('error', 'end', function(err) {
        keyCache[uri] = key;
        return cb(err, key);
      });
  }

  function pushBuffer(stream) {
    if (!hooked) {
      // pull data and detect if we need to hook before end
      var buffered = 0;
      stream.on('data', function(chunk) {
        buffered += chunk.length;
        if (!hooked && buffered >= hlsdump.bufferSize)
          hook(buffer);
      });
    }

    stream.pipe(buffer, { end: false });
    stream.once('end', 'error', function(err) {
      reading = false;
      console.error('segment done at ' + totalDuration.toFixed(0) + ' seconds, avg bitrate (kbps):', (downloadSize / (duration * 1024 / 8)).toFixed(1));
      if (err) {
        stats.meter('streamErrors').mark();
        console.error('stream error', err.stack || err);
      }
      hook(buffer);
      done();
    });
  }
});

r.once('index', function() {
  // wait until first index is returned before attaching error listener.
  // this will enable initials errors to throw
  r.on('error', function(err) {
    console.error('reader error', err.stack || err);
  });
});

r.on('end', function() {
  console.error('done');
});

var buffer = new Passthrough({highWaterMark:hlsdump.bufferSize});
var outputs = [];

if (hlsdump.udp) {
  var dst = (hlsdump.udp === true) ? null : hlsdump.udp;
  outputs.push(new UdpBlast(dst, { packetSize: 7 * 188 }));
}

if (hlsdump.output) {
  if (hlsdump.output === '-')
    outputs.push(process.stdout);
  else
    outputs.push(fs.createWriteStream(hlsdump.output));
}

// the hook is used to prebuffer
function hook(stream) {
  if (hooked) return;

  console.error('hooking output');

  var s = stream;
  if (hlsdump.sync) {
    var smooth = tssmooth();
    smooth.on('unpipe', function() {
      this.unpipe();
    });
    smooth.on('warning', function(err) {
      console.error('smoothing error', err);
    });
    s = s.pipe(smooth);
  }

  outputs.forEach(function (o) {
    s.pipe(o);
  });

  hooked = true;
}

if (!hlsdump.sync || !(hlsdump.bufferSize > 0))
  hook(buffer);

// setup stat tracking
stats.gauge('bufferBytes', function() { return buffer._readableState.length/* + buffer._writableState.length*/; });
stats.gauge('currentSegment', function() { return currentSegment; });
stats.gauge('index.first', function() { return r.index ? r.index.first_seq_no : -1; });
stats.gauge('index.last', function() { return r.index ? r.index.lastSeqNo() : -1; });
stats.gauge('totalDuration', function() { return totalDuration; });

stats.meter('streamErrors');

if (hlsdump.infoPort) {
  http.createServer(function (req, res) {
    if (req.method === 'GET') {
      var data = JSON.stringify(stats, null, ' ');
      res.writeHead(200, {
        'Content-Type': 'application/json',
        'Content-Length': data.length
      });
      res.write(data);
    }
    res.end();
  }).listen(hlsdump.infoPort);
}