// ==========================================
// BOWER: CacheClean API
// ==========================================
// Copyright 2012 Twitter, Inc
// Licensed under The MIT License
// http://opensource.org/licenses/MIT
// ==========================================

var Emitter     = require('events').EventEmitter;
var async       = require('async');
var nopt        = require('nopt');
var rimraf      = require('rimraf');
var path        = require('path');
var glob        = require('glob');
var fs          = require('fs');
var _           = require('lodash');

var help        = require('./help');
var config      = require('../core/config');
var template    = require('../util/template');
var fileExists  = require('../util/file-exists');

var optionTypes = { help: Boolean };
var shorthand   = { 'h': ['--help'] };

var processCachedPackage = function (emitter, pkg, next) {
  removeCachedPackage(pkg, function (err, exists) {
    if (err) {
      emitter.emit('error', err);
      return next();
    }

    if (exists) {
      template('action', { name: 'cache cleared', shizzle: pkg })
        .on('data', emitter.emit.bind(emitter, 'data'));
    }

    next();
  });
};

var removeCachedPackage = function (pkg, next) {
  var folder = path.join(config.cache, pkg);

  fileExists(folder, function (exists) {
    if (!exists) return next(null, false);
    rimraf(folder, function (err) {
      if (err) return next(err);
      next(null, true);
    });
  });
};

var processLinkedPackage = function (emitter, pkg, next) {
  checkAndRemoveLinkToPackage(pkg, function (err, removed) {
    if (err) {
      emitter.emit('error', err);
      return next();
    }

    if (removed) {
      template('action', { name: 'link cleared', shizzle: pkg })
        .on('data', emitter.emit.bind(emitter, 'data'));
    }

    next();
  });
};

var checkAndRemoveLinkToPackage = function (pkg, next) {
  var folder = path.join(config.links, pkg);

  fs.readlink(folder, function (err, linkString) {
    if (err && err.code === 'ENOENT') return next();

    fileExists(linkString, function (exists) {
      if (!exists) {
        return rimraf(folder, function (err) {
          if (err) return next(err);
          next(null, true);
        });
      }

      next(null, false);
    });
  });
};

module.exports = function (pkgs) {
  var emitter = new Emitter;

  async.parallel({
    cache: function (next) {
      if (!pkgs || !pkgs.length) {
        glob('./*', { cwd: config.cache }, function (err, dirs) {
          if (err) {
            emitter.emit('error', err);
            return next();
          }

          var pkgs = dirs.map(function (dir) { return dir.replace(/^\.\//, ''); });
          async.forEach(pkgs, processCachedPackage.bind(this, emitter), next);
        });
      } else {
        pkgs = _.uniq(pkgs);
        async.forEach(pkgs, processCachedPackage.bind(this, emitter), next);
      }
    },
    links: function (next) {
      if (!pkgs || !pkgs.length) {
        glob('./*', { cwd: config.links }, function (err, dirs) {
          if (err) {
            emitter.emit('error', err);
            return next();
          }

          var pkgs = dirs.map(function (dir) { return dir.replace(/^\.\//, ''); });
          async.forEach(pkgs, processLinkedPackage.bind(this, emitter), next);
        });
      } else {
        pkgs = _.uniq(pkgs);
        async.forEach(pkgs, processLinkedPackage.bind(this, emitter), next);
      }
    },
    completion: function (next) {
      rimraf(config.completion, function (err) {
        if (err) {
          emitter.emit('error', err);
          return next();
        }

        template('action', { name: 'completion cleared', shizzle: 'completion cache' })
          .on('data', emitter.emit.bind(emitter, 'data'));

        next();
      });
    }
  }, emitter.emit.bind(emitter, 'end'));

  return emitter;
};

module.exports.line = function (argv) {
  var options  = nopt(optionTypes, shorthand, argv);
  var pkgs     = options.argv.remain.slice(1);

  if (options.help) return help('cache-clean');
  return module.exports(pkgs);
};

module.exports.completion = function (opts, cb) {
  glob('./*', { cwd: config.cache }, function (err, dirs) {
    if (err) return cb(err);
    dirs = dirs.map(function (dir) {
      return dir.replace(/^\.\//, '');
    });
    cb(null, dirs);
  });
};

module.exports.completion.options = shorthand;