require 'yaml'

require 'facet/hash/traverse'
require 'facet/string/tabto'
require 'facet/dir/self/ascend'
require 'facet/kernel/require_all'

require 'facet/basicobject'


module Reap

  def self.register #( alternative_project_file=nil )
    pi = ProjectInfo.load( nil, true )
    pi.require_custom_tasks if pi
    pi
  end

  def self.projectfile?
    ProjectInfo.instance.info_file
  end

end


# Project information, generally read from a file.
# Simply by calling 'ProjectInfo.load'.
#
# ProjectInfo is a Singleton. Access it via the
# ProjectInfo.instance method.

class ProjectInfo

  INFO_FILES = [
    'ProjectInfo',
    'ReapFile',
    'projectinfo',
    'reapfile'
  ]

  class << self

    # Singelton Pattern.

    private :new

    def instance( *args, &block )
      @instance ||= new( *args, &block )
    end

    # Load the project information from a file. Generally
    # no file needs to be specified; the file will be found
    # by ascending up the current path until a default
    # file name is found (eg. ProjectInfo or Reapfile).

    def load( fpath=nil, report=false )
      if fpath
        new.read( fpath, report )
      else
        fpath = find
        instance.read( fpath, report )
      end
    end

    # Find project information file.

    def find
      info_dir, info_file = nil, nil
      Dir.ascend(Dir.pwd) do |info_dir|
        info_file = INFO_FILES.find{ |f| File.file?( File.join( info_dir, f ) ) }
        break if info_file
      end
      return nil unless info_file
      return File.join( info_dir, info_file )
    end

    #def add_file( f )
    #  INFO_FILES.unshift( f )
    #end

  end


  attr_reader :info, :info_stream, :info_dir, :info_file

  def initialize( &block )
    @info = {}
    @info_stream = nil

    define( &block ) if block_given?

    #$PROJECT_INFO = self
  end

  # Define project information programmatically.

  def define( &block )
    return unless block

    @info = HashBuilder.new( &block  ).to_h
    @info_stream = @info.to_yaml
    @info_dir = Dir.pwd #?
    @info_file = nil

    #validate
    defaults

    self
  end

  # Load project information from YAML file.

  def read( fpath, report=true )
    return unless fpath

    @info_dir = File.dirname( fpath )
    @info_file = fpath #File.basename( fpath )
    @info_stream = File.read( fpath ).strip
    @info = YAML::load( info_stream ).traverse{ |k,v| [k.to_s.downcase, v] }

    Dir.chdir(@info_dir)
    if report
      puts "(in #{Dir.pwd})" #unless dir == Dir.pwd
    end

    #validate
    defaults

    self
  end

  # Update project information.

  def update( info=nil, &block )
    if info
      @info.update( info.traverse{ |k,v| [k.to_s.downcase, v] } )
    end
    if block_given?
      @info.update( HashBuilder.new( &block  ).to_h )
    end
    @info_stream = @info.to_yaml

    #validate
    defaults

    self
  end

  # Project information file exists? (may need to change to info exists?)

  #def exists?
  #  @info_file
  #end

  # Validate project information.

  def validate #( *fields )
    val = true
    (puts "NAME is required in project information file."; val=false) unless info['name']
    (puts "VERSION is required in project information file."; val=false) unless info['version']
    exit -1 unless val
  end

  # Project information defaults.

  def defaults
    self['title']       ||= self['name'].capitalize
    self['series']      ||= '1'
    self['date']        ||= Time.now.strftime("%Y-%m-%d")
    self['author']      ||= "Anonymous"
    self['maintainer']  ||= self['author']
    self['arch']        ||= 'Any'
    self['license']     ||= 'Ruby/GPL'
    self['status']      ||= 'Beta'
    self['project']     ||= self['rubyforge'] ? self['rubyforge']['project'] : nil
    self['homepage']    ||= self['rubyforge'] ? self['rubyforge']['homepage'] : nil
  end

  # Load custom tasks.

  def require_custom_tasks
    # Universal custom tasks for all projects.
    dir = File.join( Config::CONFIG['datadir'], 'reap/task' )
    require_all( File.join(dir, '*') ) if File.directory?(dir)
    # Personal tasks for all projects.
    dir = File.expand_path( '~/.share/reap/task' )
    require_all( File.join(dir, '*') ) if File.directory?(dir)
    # Project specific tasks.
    require_all('task/*') if File.directory?('task')
  end

  # Convert to a CascadinOpenObject.

  def to_cascading_open_object
    CascadingOpenObject.new( @info )
  end

  # Information fetch.

  def [](name)
    info[name]
  end

  # Information store.

  def []=(name, x)
    info[name] = x
  end

  # Information to hash.

  def to_h
    @info
  end

end


# Build a hash from missing method calls.

class ProjectInfo::HashBuilder < BasicObject

  def initialize( blockstr=nil, &block )
    @hash = {}
    @flag = {}
    raise "both string and block given" if blockstr and block_given?
    if blockstr
      instance_eval blockstr
    else
      instance_eval &block
    end
  end

  def to_h ; @hash ; end

  def method_missing( sym, *args, &block )
    sym = sym.to_s.downcase

    if @hash.key?(sym)
      unless @flag[sym]
        @hash[sym] = [ @hash[sym] ]
        @flag[sym] = true
      end
      if block_given?
        @hash[sym] << self.__class__.new( &block ).to_h
      else
        @hash[sym] << args[0]
      end
    else
      if block_given?
        @hash[sym] = self.__class__.new( &block ).to_h
      else
        @hash[sym] = args[0]
      end
    end

  end

end