#encoding: UTF-8

# This class represents the INI file and can be used to parse, modify,

# and write INI files.

class IniFile

  include Enumerable

  class Error < StandardError; end

  VERSION = '3.0.0'

  # Public: Open an INI file and load the contents.

  #

  # filename - The name of the file as a String

  # opts     - The Hash of options (default: {})

  #            :comment   - String containing the comment character(s)

  #            :parameter - String used to separate parameter and value

  #            :encoding  - Encoding String for reading / writing

  #            :default   - The String name of the default global section

  #

  # Examples

  #

  #   IniFile.load('file.ini')

  #   #=> IniFile instance

  #

  #   IniFile.load('does/not/exist.ini')

  #   #=> nil

  #

  # Returns an IniFile instance or nil if the file could not be opened.

  def self.load( filename, opts = {} )

    return unless File.file? filename

    new(opts.merge(:filename => filename))

  end

  # Get and set the filename

  attr_accessor :filename

  # Get and set the encoding

  attr_accessor :encoding

  # Public: Create a new INI file from the given set of options. If :content

  # is provided then it will be used to populate the INI file. If a :filename

  # is provided then the contents of the file will be parsed and stored in the

  # INI file. If neither the :content or :filename is provided then an empty

  # INI file is created.

  #

  # opts - The Hash of options (default: {})

  #   :content   - The String/Hash containing the INI contents

  #   :comment   - String containing the comment character(s)

  #   :parameter - String used to separate parameter and value

  #   :encoding  - Encoding String for reading / writing

  #   :default   - The String name of the default global section

  #   :filename  - The filename as a String

  #

  # Examples

  #

  #   IniFile.new

  #   #=> an empty IniFile instance

  #

  #   IniFile.new( :content => "[global]\nfoo=bar" )

  #   #=> an IniFile instance

  #

  #   IniFile.new( :filename => 'file.ini', :encoding => 'UTF-8' )

  #   #=> an IniFile instance

  #

  #   IniFile.new( :content => "[global]\nfoo=bar", :comment => '#' )

  #   #=> an IniFile instance

  #

  def initialize( opts = {} )

    @comment  = opts.fetch(:comment, ';#')

    @param    = opts.fetch(:parameter, '=')

    @encoding = opts.fetch(:encoding, nil)

    @default  = opts.fetch(:default, 'global')

    @filename = opts.fetch(:filename, nil)

    content   = opts.fetch(:content, nil)

    @ini = Hash.new {|h,k| h[k] = Hash.new}

    if    content.is_a?(Hash) then merge!(content)

    elsif content             then parse(content)

    elsif @filename           then read

    end

  end

  # Public: Write the contents of this IniFile to the file system. If left

  # unspecified, the currently configured filename and encoding will be used.

  # Otherwise the filename and encoding can be specified in the options hash.

  #

  # opts - The default options Hash

  #        :filename - The filename as a String

  #        :encoding - The encoding as a String

  #

  # Returns this IniFile instance.

  def write( opts = {} )

    filename = opts.fetch(:filename, @filename)

    encoding = opts.fetch(:encoding, @encoding)

    mode = encoding ? "w:#{encoding}" : "w"

    File.open(filename, mode) do |f|

      @ini.each do |section,hash|

        f.puts "[#{section}]"

        hash.each {|param,val| f.puts "#{param} #{@param} #{escape_value val}"}

        f.puts

      end

    end

    self

  end

  alias :save :write

  # Public: Read the contents of the INI file from the file system and replace

  # and set the state of this IniFile instance. If left unspecified the

  # currently configured filename and encoding will be used when reading from

  # the file system. Otherwise the filename and encoding can be specified in

  # the options hash.

  #

  # opts - The default options Hash

  #        :filename - The filename as a String

  #        :encoding - The encoding as a String

  #

  # Returns this IniFile instance if the read was successful; nil is returned

  # if the file could not be read.

  def read( opts = {} )

    filename = opts.fetch(:filename, @filename)

    encoding = opts.fetch(:encoding, @encoding)

    return unless File.file? filename

    mode = encoding ? "r:#{encoding}" : "r"

    File.open(filename, mode) { |fd| parse fd }

    self

  end

  alias :restore :read

  # Returns this IniFile converted to a String.

  def to_s

    s = []

    @ini.each do |section,hash|

      s << "[#{section}]"

      hash.each {|param,val| s << "#{param} #{@param} #{escape_value val}"}

      s << ""

    end

    s.join("\n")

  end

  # Returns this IniFile converted to a Hash.

  def to_h

    @ini.dup

  end

  # Public: Creates a copy of this inifile with the entries from the

  # other_inifile merged into the copy.

  #

  # other - The other IniFile.

  #

  # Returns a new IniFile.

  def merge( other )

    self.dup.merge!(other)

  end

  # Public: Merges other_inifile into this inifile, overwriting existing

  # entries. Useful for having a system inifile with user overridable settings

  # elsewhere.

  #

  # other - The other IniFile.

  #

  # Returns this IniFile.

  def merge!( other )

    return self if other.nil?

    my_keys = @ini.keys

    other_keys = case other

      when IniFile

        other.instance_variable_get(:@ini).keys

      when Hash

        other.keys

      else

        raise Error, "cannot merge contents from '#{other.class.name}'"

      end

    (my_keys & other_keys).each do |key|

      case other[key]

      when Hash

        @ini[key].merge!(other[key])

      when nil

        nil

      else

        raise Error, "cannot merge section #{key.inspect} - unsupported type: #{other[key].class.name}"

      end

    end

    (other_keys - my_keys).each do |key|

      @ini[key] = case other[key]

        when Hash

          other[key].dup

        when nil

          {}

        else

          raise Error, "cannot merge section #{key.inspect} - unsupported type: #{other[key].class.name}"

        end

    end

    self

  end

  # Public: Yield each INI file section, parameter, and value in turn to the

  # given block.

  #

  # block - The block that will be iterated by the each method. The block will

  #         be passed the current section and the parameter/value pair.

  #

  # Examples

  #

  #   inifile.each do |section, parameter, value|

  #     puts "#{parameter} = #{value} [in section - #{section}]"

  #   end

  #

  # Returns this IniFile.

  def each

    return unless block_given?

    @ini.each do |section,hash|

      hash.each do |param,val|

        yield section, param, val

      end

    end

    self

  end

  # Public: Yield each section in turn to the given block.

  #

  # block - The block that will be iterated by the each method. The block will

  #         be passed the current section as a Hash.

  #

  # Examples

  #

  #   inifile.each_section do |section|

  #     puts section.inspect

  #   end

  #

  # Returns this IniFile.

  def each_section

    return unless block_given?

    @ini.each_key {|section| yield section}

    self

  end

  # Public: Remove a section identified by name from the IniFile.

  #

  # section - The section name as a String.

  #

  # Returns the deleted section Hash.

  def delete_section( section )

    @ini.delete section.to_s

  end

  # Public: Get the section Hash by name. If the section does not exist, then

  # it will be created.

  #

  # section - The section name as a String.

  #

  # Examples

  #

  #   inifile['global']

  #   #=> global section Hash

  #

  # Returns the Hash of parameter/value pairs for this section.

  def []( section )

    return nil if section.nil?

    @ini[section.to_s]

  end

  # Public: Set the section to a hash of parameter/value pairs.

  #

  # section - The section name as a String.

  # value   - The Hash of parameter/value pairs.

  #

  # Examples

  #

  #   inifile['tenderloin'] = { 'gritty' => 'yes' }

  #   #=> { 'gritty' => 'yes' }

  #

  # Returns the value Hash.

  def []=( section, value )

    @ini[section.to_s] = value

  end

  # Public: Create a Hash containing only those INI file sections whose names

  # match the given regular expression.

  #

  # regex - The Regexp used to match section names.

  #

  # Examples

  #

  #   inifile.match(/^tree_/)

  #   #=> Hash of matching sections

  #

  # Return a Hash containing only those sections that match the given regular

  # expression.

  def match( regex )

    @ini.dup.delete_if { |section, _| section !~ regex }

  end

  # Public: Check to see if the IniFile contains the section.

  #

  # section - The section name as a String.

  #

  # Returns true if the section exists in the IniFile.

  def has_section?( section )

    @ini.has_key? section.to_s

  end

  # Returns an Array of section names contained in this IniFile.

  def sections

    @ini.keys

  end

  # Public: Freeze the state of this IniFile object. Any attempts to change

  # the object will raise an error.

  #

  # Returns this IniFile.

  def freeze

    super

    @ini.each_value {|h| h.freeze}

    @ini.freeze

    self

  end

  # Public: Mark this IniFile as tainted -- this will traverse each section

  # marking each as tainted.

  #

  # Returns this IniFile.

  def taint

    super

    @ini.each_value {|h| h.taint}

    @ini.taint

    self

  end

  # Public: Produces a duplicate of this IniFile. The duplicate is independent

  # of the original -- i.e. the duplicate can be modified without changing the

  # original. The tainted state of the original is copied to the duplicate.

  #

  # Returns a new IniFile.

  def dup

    other = super

    other.instance_variable_set(:@ini, Hash.new {|h,k| h[k] = Hash.new})

    @ini.each_pair {|s,h| other[s].merge! h}

    other.taint if self.tainted?

    other

  end

  # Public: Produces a duplicate of this IniFile. The duplicate is independent

  # of the original -- i.e. the duplicate can be modified without changing the

  # original. The tainted state and the frozen state of the original is copied

  # to the duplicate.

  #

  # Returns a new IniFile.

  def clone

    other = dup

    other.freeze if self.frozen?

    other

  end

  # Public: Compare this IniFile to some other IniFile. For two INI files to

  # be equivalent, they must have the same sections with the same parameter /

  # value pairs in each section.

  #

  # other - The other IniFile.

  #

  # Returns true if the INI files are equivalent and false if they differ.

  def eql?( other )

    return true if equal? other

    return false unless other.instance_of? self.class

    @ini == other.instance_variable_get(:@ini)

  end

  alias :== :eql?

  # Escape special characters.

  #

  # value - The String value to escape.

  #

  # Returns the escaped value.

  def escape_value( value )

    value = value.to_s.dup

    value.gsub!(%r/\\([0nrt])/, '\\\\\1')

    value.gsub!(%r/\n/, '\n')

    value.gsub!(%r/\r/, '\r')

    value.gsub!(%r/\t/, '\t')

    value.gsub!(%r/\0/, '\0')

    value

  end

  # Parse the given content and store the information in this IniFile

  # instance. All data will be cleared out and replaced with the information

  # read from the content.

  #

  # content - A String or a file descriptor (must respond to `each_line`)

  #

  # Returns this IniFile.

  def parse( content )

    parser = Parser.new(@ini, @param, @comment, @default)

    parser.parse(content)

    self

  end

  # The IniFile::Parser has the responsibility of reading the contents of an

  # .ini file and storing that information into a ruby Hash. The object being

  # parsed must respond to `each_line` - this includes Strings and any IO

  # object.

  class Parser

    attr_writer :section

    attr_accessor :property

    attr_accessor :value

    # Create a new IniFile::Parser that can be used to parse the contents of

    # an .ini file.

    #

    # hash    - The Hash where parsed information will be stored

    # param   - String used to separate parameter and value

    # comment - String containing the comment character(s)

    # default - The String name of the default global section

    #

    def initialize( hash, param, comment, default )

      @hash = hash

      @default = default

      comment = comment.to_s.empty? ? "\\z" : "\\s*(?:[#{comment}].*)?\\z"

      @section_regexp  = %r/\A\s*\[([^\]]+)\]#{comment}/

      @ignore_regexp   = %r/\A#{comment}/

      @property_regexp = %r/\A(.*?)(?<!\\)#{param}(.*)\z/

      @open_quote      = %r/\A\s*(".*)\z/

      @close_quote     = %r/\A(.*(?<!\\)")#{comment}/

      @full_quote      = %r/\A\s*(".*(?<!\\)")#{comment}/

      @trailing_slash  = %r/\A(.*)(?<!\\)\\#{comment}/

      @normal_value    = %r/\A(.*?)#{comment}/

    end

    # Returns `true` if the current value starts with a leading double quote.

    # Otherwise returns false.

    def leading_quote?

      value && value =~ %r/\A"/

    end

    # Given a string, attempt to parse out a value from that string. This

    # value might be continued on the following line. So this method returns

    # `true` if it is expecting more data.

    #

    # string - String to parse

    #

    # Returns `true` if the next line is also part of the current value.

    # Returns `fase` if the string contained a complete value.

    def parse_value( string )

      continuation = false

      # if our value starts with a double quote, then we are in a

      # line continuation situation

      if leading_quote?

        # check for a closing quote at the end of the string

        if string =~ @close_quote

          value << $1

        # otherwise just append the string to the value

        else

          value << string

          continuation = true

        end

      # not currently processing a continuation line

      else

        case string

        when @full_quote

          self.value = $1

        when @open_quote

          self.value = $1

          continuation = true

        when @trailing_slash

          self.value ?  self.value << $1 : self.value = $1

          continuation = true

        when @normal_value

          self.value ?  self.value << $1 : self.value = $1

        else

          error

        end

      end

      if continuation

        self.value << $/ if leading_quote?

      else

        process_property

      end

      continuation

    end

    # Parse the ini file contents. This will clear any values currently stored

    # in the ini hash.

    #

    # content - Any object that responds to `each_line`

    #

    # Returns nil.

    def parse( content )

      return unless content

      continuation = false

      @hash.clear

      @line = nil

      self.section = nil

      content.each_line do |line|

        @line = line.chomp

        if continuation

          continuation = parse_value @line

        else

          case @line

          when @ignore_regexp

            nil

          when @section_regexp

            self.section = @hash[$1]

          when @property_regexp

            self.property = $1.strip

            error if property.empty?