var imports     = require('soop').imports();
var config      = imports.config || require('./config');
var log         = imports.log || require('./util/log');
var Opcode      = imports.Opcode || require('./Opcode');
var buffertools = imports.buffertools || require('buffertools');

// Make opcodes available as pseudo-constants
for (var i in Opcode.map) {
  eval(i + ' = ' + Opcode.map[i] + ';');
}

var util   = imports.util || require('./util/util');
var Parser = imports.Parser || require('./util/BinaryParser');
var Put    = imports.Put || require('bufferput');

var TX_UNKNOWN = 0;
var TX_PUBKEY = 1;
var TX_PUBKEYHASH = 2;
var TX_MULTISIG = 3;
var TX_SCRIPTHASH = 4;

var TX_TYPES = [
  'unknown',
  'pubkey',
  'pubkeyhash',
  'multisig',
  'scripthash'
];

function Script(buffer) {
  if(buffer) {
    this.buffer = buffer;
  } else {
    this.buffer = util.EMPTY_BUFFER;
  }
  this.chunks = [];
  this.parse();
};
this.class = Script;

Script.TX_UNKNOWN=TX_UNKNOWN;
Script.TX_PUBKEY=TX_PUBKEY;
Script.TX_PUBKEYHASH=TX_PUBKEYHASH;
Script.TX_MULTISIG=TX_MULTISIG;
Script.TX_SCRIPTHASH=TX_SCRIPTHASH;

Script.prototype.parse = function () {
  this.chunks = [];

  var parser = new Parser(this.buffer);
  while (!parser.eof()) {
    var opcode = parser.word8();

    var len;
    if (opcode > 0 && opcode < OP_PUSHDATA1) {
      // Read some bytes of data, opcode value is the length of data
      this.chunks.push(parser.buffer(opcode));
    } else if (opcode == OP_PUSHDATA1) {
      len = parser.word8();
      this.chunks.push(parser.buffer(len));
    } else if (opcode == OP_PUSHDATA2) {
      len = parser.word16le();
      this.chunks.push(parser.buffer(len));
    } else if (opcode == OP_PUSHDATA4) {
      len = parser.word32le();
      this.chunks.push(parser.buffer(len));
    } else {
      this.chunks.push(opcode);
    }
  }
};

Script.prototype.isPushOnly = function ()
{
  for (var i = 0; i < this.chunks.length; i++)
    if (!Buffer.isBuffer(this.chunks[i]))
      return false;

  return true;
};

Script.prototype.isP2SH = function ()
{
  return (this.chunks.length == 3 &&
    this.chunks[0] == OP_HASH160 &&
    Buffer.isBuffer(this.chunks[1]) &&
    this.chunks[1].length == 20 &&
    this.chunks[2] == OP_EQUAL);
};

Script.prototype.isPubkey = function ()
{
  return (this.chunks.length == 2 &&
        Buffer.isBuffer(this.chunks[0]) &&
        this.chunks[1] == OP_CHECKSIG);
};

Script.prototype.isPubkeyHash = function ()
{
  return (this.chunks.length == 5 &&
          this.chunks[0] == OP_DUP &&
          this.chunks[1] == OP_HASH160 &&
    Buffer.isBuffer(this.chunks[2]) &&
    this.chunks[2].length == 20 &&
          this.chunks[3] == OP_EQUALVERIFY &&
          this.chunks[4] == OP_CHECKSIG);
};

function isSmallIntOp(opcode)
{
  return ((opcode == OP_0) ||
        ((opcode >= OP_1) && (opcode <= OP_16)));
};

Script.prototype.isMultiSig = function ()
{
  return (this.chunks.length > 3 &&
        isSmallIntOp(this.chunks[0]) &&
        isSmallIntOp(this.chunks[this.chunks.length-2]) &&
    this.chunks[this.chunks.length-1] == OP_CHECKMULTISIG);
};

Script.prototype.finishedMultiSig = function()
{
  var nsigs = 0;
  for (var i = 0; i < this.chunks.length-1; i++)
    if (this.chunks[i] !== 0)
      nsigs++;

  var serializedScript = this.chunks[this.chunks.length-1];
  var script = new Script(serializedScript);
  var nreq = script.chunks[0] - 80; //see OP_2-OP_16

  if (nsigs == nreq)
    return true;
  else
    return false;
}

Script.prototype.removePlaceHolders = function()
{
  var chunks = [];
  for (var i in this.chunks)
  {
    if (this.chunks.hasOwnProperty(i)) {
      var chunk = this.chunks[i];
      if (chunk != 0)
        chunks.push(chunk);
    }
  }
  this.chunks = chunks;
  this.updateBuffer();
  return this;
}

Script.prototype.prependOp0 = function()
{
  var chunks = [0];
  for (i in this.chunks) {
    if (this.chunks.hasOwnProperty(i)) {
      chunks.push(this.chunks[i]);
    }
  }
  this.chunks = chunks;
  this.updateBuffer();
  return this;
}

// is this a script form we know?
Script.prototype.classify = function ()
{
  if (this.isPubkeyHash())
  return TX_PUBKEYHASH;
if (this.isP2SH())
  return TX_SCRIPTHASH;
if (this.isMultiSig())
  return TX_MULTISIG;
if (this.isPubkey())
  return TX_PUBKEY;
return TX_UNKNOWN;
};

// extract useful data items from known scripts
Script.prototype.capture = function ()
{
  var txType = this.classify();
var res = [];
switch (txType) {
case TX_PUBKEY:
  res.push(this.chunks[0]);
  break;
case TX_PUBKEYHASH:
  res.push(this.chunks[2]);
  break;
case TX_MULTISIG:
  for (var i = 1; i < (this.chunks.length - 2); i++)
    res.push(this.chunks[i]);
  break;
case TX_SCRIPTHASH:
  res.push(this.chunks[1]);
  break;

case TX_UNKNOWN:
default:
  // do nothing
  break;
}

return res;
};

// return first extracted data item from script
Script.prototype.captureOne = function ()
{
  var arr = this.capture();
return arr[0];
};

Script.prototype.getOutType = function ()
{
  var txType = this.classify();
  switch (txType) {
    case TX_PUBKEY:   return 'Pubkey';
    case TX_PUBKEYHASH: return 'Address';
    default:    return 'Strange';
  }
};

Script.prototype.getRawOutType = function() {
  return TX_TYPES[this.classify()];
};

Script.prototype.simpleOutHash = function ()
{
  switch (this.getOutType()) {
  case 'Address':
    return this.chunks[2];
  case 'Pubkey':
    return util.sha256ripe160(this.chunks[0]);
  default:
    log.debug("Encountered non-standard scriptPubKey");
    log.debug("Strange script was: " + this.toString());
    return null;
  }
};

Script.prototype.getInType = function ()
{
  if (this.chunks.length == 1) {
    // Direct IP to IP transactions only have the public key in their scriptSig.
    return 'Pubkey';
  } else if (this.chunks.length == 2 &&
              Buffer.isBuffer(this.chunks[0]) &&
              Buffer.isBuffer(this.chunks[1])) {
    return 'Address';
  } else {
    return 'Strange';
  }
};

Script.prototype.simpleInPubKey = function ()
{
  switch (this.getInType()) {
  case 'Address':
    return this.chunks[1];
  case 'Pubkey':
    return null;
  default:
    log.debug("Encountered non-standard scriptSig");
    log.debug("Strange script was: " + this.toString());
    return null;
  }
};

Script.prototype.getBuffer = function ()
{
  return this.buffer;
};

Script.prototype.getStringContent = function (truncate, maxEl)
{
  if (truncate === null) {
    truncate = true;
  }

  if ("undefined" === typeof maxEl) {
    maxEl = 15;
  }

  var script = '';
  for (var i = 0, l = this.chunks.length; i < l; i++) {
    var chunk = this.chunks[i];

    if (i > 0) {
      script += " ";
    }

    if (Buffer.isBuffer(chunk)) {
      script += "0x"+util.formatBuffer(chunk, truncate ? null : 0);
    } else {
      script += Opcode.reverseMap[chunk];
    }

    if (maxEl && i > maxEl) {
      script += " ...";
      break;
    }
  }
  return script;
};

Script.prototype.toString = function (truncate, maxEl)
{
  var script = "<Script ";
  script += this.getStringContent(truncate, maxEl);
  script += ">";
  return script;
};


Script.prototype.writeOp = function (opcode)
{
  var buf = Buffer(this.buffer.length + 1);
  this.buffer.copy(buf);
  buf.writeUInt8(opcode, this.buffer.length);

  this.buffer = buf;

  this.chunks.push(opcode);
};

Script.prototype.writeN = function (n)
{
  if (n < 0 || n > 16)
    throw new Error("writeN: out of range value " + n);

  if (n == 0)
    this.writeOp(OP_0);
  else
    this.writeOp(OP_1 + n - 1);
};

function prefixSize(data_length)
{
  if (data_length < OP_PUSHDATA1) {
    return 1;
  } else if (data_length <= 0xff) {
    return 1 + 1;
  } else if (data_length <= 0xffff) {
    return 1 + 2;
  } else {
    return 1 + 4;
  }
};

function encodeLen(data_length) {
  var buf = undefined;
  if (data_length < OP_PUSHDATA1) {
    buf = new Buffer(1);
    buf.writeUInt8(data_length, 0);
  }
  
  else if (data_length <= 0xff) {
    buf = new Buffer(1 + 1);
    buf.writeUInt8(OP_PUSHDATA1, 0);
    buf.writeUInt8(data_length, 1);
  }
  
  else if (data_length <= 0xffff) {
    buf = new Buffer(1 + 2);
    buf.writeUInt8(OP_PUSHDATA2, 0);
    buf.writeUInt16LE(data_length, 1);
  }
  
  else {
    buf = new Buffer(1 + 4);
    buf.writeUInt8(OP_PUSHDATA4, 0);
    buf.writeUInt32LE(data_length, 1);
  }

  return buf;
};

Script.prototype.writeBytes = function (data)
{
  var newSize = this.buffer.length + prefixSize(data.length) + data.length;
  this.buffer = Buffer.concat([this.buffer, encodeLen(data.length), data]);
  this.chunks.push(data);
};

Script.prototype.updateBuffer = function ()
{
  this.buffer = Script.chunksToBuffer(this.chunks);
};

Script.prototype.findAndDelete = function (chunk)
{
  var dirty = false;
  if (Buffer.isBuffer(chunk)) {
    for (var i = 0, l = this.chunks.length; i < l; i++) {
      if (Buffer.isBuffer(this.chunks[i]) &&
          buffertools.compare(this.chunks[i], chunk) === 0) {
        this.chunks.splice(i, 1);
        dirty = true;
      }
    }
  } else if ("number" === typeof chunk) {
    for (var i = 0, l = this.chunks.length; i < l; i++) {
      if (this.chunks[i] === chunk) {
        this.chunks.splice(i, 1);
        dirty = true;
      }
    }
  } else {
    throw new Error("Invalid chunk datatype.");
  }
  if (dirty) {
    this.updateBuffer();
  }
};

/**
  * Creates a simple OP_CHECKSIG with pubkey output script.
  *
  * These are used for coinbase transactions and at some point were used for
  * IP-based transactions as well.
  */
Script.createPubKeyOut = function (pubkey) {
  var script = new Script();
  script.writeBytes(pubkey);
  script.writeOp(OP_CHECKSIG);
  return script;
};

/**
  * Creates a standard txout script.
  */
Script.createPubKeyHashOut = function (pubKeyHash) {
  var script = new Script();
  script.writeOp(OP_DUP);
  script.writeOp(OP_HASH160);
  script.writeBytes(pubKeyHash);
  script.writeOp(OP_EQUALVERIFY);
  script.writeOp(OP_CHECKSIG);
  return script;
};

Script.createMultisig = function(n_required, keys) {
  var script = new Script();
  script.writeN(n_required);
  keys.forEach(function(key) {
    script.writeBytes(key);
  });
  script.writeN(keys.length);
  script.writeOp(OP_CHECKMULTISIG);
  return script;
};

Script.createP2SH = function(scriptHash) {
  var script = new Script();
  script.writeOp(OP_HASH160);
  script.writeBytes(scriptHash);
  script.writeOp(OP_EQUAL);
  return script;
};

Script.fromTestData = function (testData) {
  testData = testData.map(function (chunk) {
    if ("string" === typeof chunk) {
      return new Buffer(chunk, 'hex');
    } else {
      return chunk;
    }
  });

  var script = new Script();
  script.chunks = testData;
  script.updateBuffer();
  return script;
};

Script.fromChunks = function (chunks) {
  var script = new Script();
  script.chunks = chunks;
  script.updateBuffer();
  return script;
};

Script.chunksToBuffer = function (chunks) {
  var buf = new Put();

  for (var i = 0, l = chunks.length; i < l; i++) {
    var data = chunks[i];
    if (Buffer.isBuffer(data)) {
      if (data.length < OP_PUSHDATA1) {
        buf.word8(data.length);
      } else if (data.length <= 0xff) {
        buf.word8(OP_PUSHDATA1);
        buf.word8(data.length);
      } else if (data.length <= 0xffff) {
        buf.word8(OP_PUSHDATA2);
        buf.word16le(data.length);
      } else {
        buf.word8(OP_PUSHDATA4);
        buf.word32le(data.length);
      }
      buf.put(data);
    } else if ("number" === typeof data) {
      buf.word8(data);
    } else {
      throw new Error("Script.chunksToBuffer(): Invalid chunk datatype");
    }
  }
  return buf.buffer();
};

module.exports = require('soop')(Script);