minUrequireVersion = "0.7.0-beta.11"

fs = require 'fs'
upath = require 'upath'
_ = require 'lodash'
_.mixin (require 'underscore.string').exports()

try
  urequire = require 'urequire'
catch err
  throw """
    grunt-urequire: you 'll need `npm install urequire --save-dev` (version >= 0.7.0) already installed locally.
    `urequire` is only a `peerDependencies` of `grunt-urequire`.\n""" + err.toString()

pkg = JSON.parse fs.readFileSync upath.join __dirname, '../package.json'
if require('semver').lt urequire.VERSION, minUrequireVersion
  throw "`urequire` version >= '#{minUrequireVersion}' is needed for `grunt-urequire` v'#{pkg.version}'"

filesWatch1st = null

module.exports = (grunt) ->
  urequire.grunt or= grunt

  urequire.gruntDeriveLoader = _.memoize (derive)-> # load from grunt config, or file if not found
    if _.isString derive
      if cfgObject = grunt.config.get("urequire.#{derive}") # @todo: support root level grunt objects (eg RequireJs) using '/' ?
        cfgObject
      else
        try           # @todo: fix file relative positions in deriveReader
          cfgObject = require fs.realpathSync derive
        catch er
        if cfgObject
          cfgObject
        else
          throw new Error """
            grunt-urequire: Error loading configuration files:
            derive '#{derive}' not found in grunt's config, nor is a valid filename
            """
    else
      if _.isPlainObject derive
        derive
      else
        throw new Error """
          grunt-urequire: Error loading configuration files: Unknown derive :\n #{derive}
        """
  urequire.getGruntConfigsForTarget = (target)->
    data = grunt.config.get("urequire.#{target}")
    [                                                   # init our grunt-urequire with 4 configs:
      {build: target: target}                           # target becomes the mandatory `build.target`
      data                                              # grunt's data under target
      if _.isPlainObject(data) and _.isUndefined(data.derive)
        grunt.config.get("urequire._defaults")          # _defaults if no other derive, if it exists
      grunt.config.get("urequire._all")                 # _all if exists. undefined is fine
    ]

  grunt.verbose.writeln "grunt-urequire v#{pkg.version}: Registering grunt.event.on 'watch' once"
  grunt.event.on 'watch', (action, file)->
    if (_.any urequire.BBExecuted, (bb)-> bb.filesWatch) # any bb with filesWatch ?
      filesWatch1st = null #dont need that anymore, only 1st time
      for bb in urequire.BBExecuted
        grunt.verbose.writeln "grunt-urequire: adding to filesWatch of bundleBuilder.build.target = '#{bb.build.target}': '#{file}'"
        bb.filesWatch.push file #  all bbs have a filesWatch = []  before they build
    else # grunt urequire tasks have not run yet - we dont know how many there are coming through!
      grunt.verbose.writeln "grunt-urequire: 1st watch events batch, adding to filesWatch1st: '#{file}' "
      (filesWatch1st or= []).push file

  grunt.verbose.writeln "grunt-urequire v#{pkg.version}: registerMultiTask 'urequire' once"
  grunt.registerMultiTask "urequire", "Convert nodejs & AMD modules using uRequire", ->

    if @target[0] isnt '_' #  ignore derived @target's(those staring with `_`, eg `_defaults`)
      # for our @target, create a bundleBuilder (if not already there) using configs derived from grunt's @data
      if bundleBuilder = urequire.findBBCreated @target
        grunt.verbose.writeln "grunt-urequire v#{pkg.version}: already has a bundleBuilder for task @target = '#{@target}'"
      else
        grunt.verbose.writeln "grunt-urequire v#{pkg.version}: initializing bundleBuilder for task @target = '#{@target}'"
        bundleBuilder = new urequire.BundleBuilder urequire.getGruntConfigsForTarget(@target), urequire.gruntDeriveLoader # stores target

      # run a build, when we have a bundleBuilder
      if bundleBuilder and bundleBuilder.bundle and bundleBuilder.build
        # have we accumulated 'watch' events / files that need to be refreshed ?
        if not filesWatch = bundleBuilder.filesWatch
          filesWatch = filesWatch1st # might be null, or have changed files
        if not _.isEmpty filesWatch
          changedFiles = _.map (_.unique filesWatch), (file)-> # accept only unique files
            upath.relative bundleBuilder.bundle.path, file      # with cwd being `bundle.path`

          grunt.verbose.writeln "grunt-urequire: executing a partial build for @target = '#{@target}', changed files relative to bundle.path='#{bundleBuilder.bundle.path}' :\n", changedFiles
          bundleBuilder.filesWatch = [] # reset filesWatch on BB for next time
          bundleBuilder.build.watch.enabled = true # cause it may was invoked through the watch of another bundleBuilder

        # auto setup & run a grunt-contrib-watch for bb
        if bundleBuilder.build.watch.enabled is true
          if bundleBuilder.build.watch.info is 'grunt-urequire'
            require("urequire-ab-grunt-contrib-watch") null, bundleBuilder
          else
            if (bundleBuilder.build.count is 0) and (bundleBuilder.build.watch.info not in ['grunt-urequire', 'urequire-ab-grunt-contrib-watch'])
              grunt.log.subhead "grunt-urequire: found `watch` at target `#{bundleBuilder.build.target}` but without `'grunt-urequire'`: not automatically running `grunt-contrib-watch`"

        gruntDone = @async()
        gruntStart = new Date()
        grunt.verbose.writeln "Executing a full build for @target `#{@target}`" if not changedFiles
        bundleBuilder.buildBundle(changedFiles).then(
          (bb)=>
            grunt.log.ok "grunt-urequire v#{pkg.version}: task '#{@target}' build ##{bundleBuilder.build.count} done in #{(new Date() - gruntStart) / 1000} secs (:-)"
            gruntDone true

          (errors)=>
            grunt.log.error errors if not _.size errors
            grunt.log.error "grunt-urequire v#{pkg.version}: task '#{@target}' build ##{bundleBuilder.build.count} took #{(new Date() - gruntStart) / 1000} secs and has #{_.size errors} errors ):-(" +
              (if bundleBuilder?.build?.watch.enabled is true then "NOT QUITING because of watch!)" else '')
            gruntDone bundleBuilder?.build?.watch.enabled
        )