###
Task: pages
Description: generates static HTML files
Dependencies: grunt, fs
Contributor: @searls, @adamlogic

Supported formats:
html - template will merely be copied
underscore (aliases: "us", "jst") - underscore templating
handlebar (aliases: "hb", "handlebars") - handlebars templating

When the templates are processed, they will be passed the grunt configuration object,
which contains lots of useful goodies.
###

module.exports = (grunt) ->
  _ = require("lodash")
  fs = require("fs")

  grunt.registerMultiTask "pages", "generates static HTML files", ->
    for filePair in @files
      for src in filePair.src
        format = (extensionOf(src) || "html").toLowerCase()
        dest = if filePair.dest.match(/\.html$/)
          filePair.dest
        else
          [ filePair.dest.replace(/\/$/,''),
            src.replace(/.*\//, '').replace(/\..+$/, '.html') ].join '/'

        if format == "html"
          grunt.file.copy(src, dest)
        else
          source = grunt.file.read(src)
          context = buildTemplateContext(this)
          grunt.file.write(dest, htmlFor(format, source, context))

        grunt.log.writeln("#{dest} generated from #{src}")

  extensionOf = (fileName) ->
    _.last(fileName.match(/[^.]*$/))

  htmlFor = (format, source, context) ->
    if format in ["underscore", "us", "jst"]
      _.template(source)(context)
    else if format in ["handlebar", "hb", "hbs", "handlebars"]
      locateHandlebars().compile(source)(context)
    else
      ""

  locateHandlebars = ->
    handlebarsPath = process.cwd()+'/node_modules/handlebars'
    if fs.existsSync(handlebarsPath)
      require(handlebarsPath)
    else
      grunt.log.writeln """
        NOTE: please add the `handlebars` module to your package.json, as Lineman doesn't include
        it directly. Attempting to Handlebars load naively (this may blow up). Also be sure to
        add the Handlebars runtime to your `vendor/js` directory (http://handlebarsjs.com)
        """
      require("handlebars")

  buildTemplateContext = (task) ->
    _.extend(grunt.config.get(), task.data.context)