#
# This file was ported to ruby from Composer php source code file.
# Original Source: Composer\Json\JsonFormatter.php
#
# (c) Nils Adermann <naderman@naderman.de>
#     Jordi Boggiano <j.boggiano@seld.be>
#
# For the full copyright and license information, please view the LICENSE
# file that was distributed with this source code.
#

# JSON_HEX_TAG => 1
# JSON_HEX_AMP => 2
# JSON_HEX_APOS => 4
# JSON_HEX_QUOT => 8
# JSON_FORCE_OBJECT => 16
# JSON_NUMERIC_CHECK => 32
# JSON_UNESCAPED_SLASHES => 64
# JSON_PRETTY_PRINT => 128
# JSON_UNESCAPED_UNICODE => 256

module Composer
  module Json
    #  * Formats json strings used for php < 5.4 because the json_encode doesn't
    #  * supports the flags JSON_UNESCAPED_SLASHES | JSON_PRETTY_PRINT | JSON_UNESCAPED_UNICODE
    #  * in these versions
    #
    # PHP Authors:
    # Konstantin Kudryashiv <ever.zet@gmail.com>
    # Jordi Boggiano <j.boggiano@seld.be>
    #
    # Ruby Authors:
    # Ioannis Kappas <ikappas@devworks.gr>
    class JsonFormatter

      JSON_HEX_TAG = 1
      JSON_HEX_AMP = 2
      JSON_HEX_APOS = 4
      JSON_HEX_QUOT = 8
      JSON_FORCE_OBJECT = 16
      JSON_NUMERIC_CHECK = 32
      JSON_UNESCAPED_SLASHES = 64
      JSON_PRETTY_PRINT = 128
      JSON_UNESCAPED_UNICODE = 256

      class << self
        # This code is based on the function found at:
        # http://recursive-design.com/blog/2008/03/11/format-json-with-php/
        #
        # Originally licensed under MIT by Dave Perrett <mail@recursive-design.com>
        #
        # @param json string
        # @param unescape_unicode bool Un escape unicode
        # @param unescape_slashes bool  Un escape slashes
        # @return string
        def format(json, options)

          result = ''
          pos = 0
          str_len = json.length
          indent_str = '    '
          new_line = "\n"
          out_of_quotes = true
          buffer = ''
          no_escape = true

          for i in 0..(str_len - 1)

            # Grab the next character in the string
            char = json[i]

            # Are we inside a quoted string?
            if '"' === char && no_escape
              out_of_quotes = !out_of_quotes
            end

            if !out_of_quotes
              buffer << char
              no_escape = '\\' === char ? !no_escape : true
              next
            elsif buffer != ''
              if options & JSON_HEX_TAG === JSON_HEX_TAG
                buffer.gsub!('<', '\\u003C')
                buffer.gsub!('>', '\\u003E')
              end
              if options & JSON_HEX_AMP === JSON_HEX_AMP
                buffer.gsub!('&', '\\u0026')
              end
              if options & JSON_HEX_APOS === JSON_HEX_APOS
                buffer.gsub!('\'', '\\u0027')
              end
              if options & JSON_HEX_QUOT === JSON_HEX_QUOT
                buffer.gsub!('\"', '\\u0022')
              end
              if options & JSON_UNESCAPED_SLASHES === JSON_UNESCAPED_SLASHES
                buffer.gsub!('\\/', '/')
              end
              if options & JSON_UNESCAPED_UNICODE === JSON_UNESCAPED_UNICODE
                buffer.gsub!(/\\u([\da-fA-F]{4})/) {|m| [$1].pack('H*').unpack('n*').pack('U*')}
              end

              result << buffer + char
              buffer = ''
              next
            end

            if options & JSON_PRETTY_PRINT === JSON_PRETTY_PRINT
              if char === ':'
              # Add a space after the : character
              char << ' '
              elsif char === '}' || char === ']'
                pos -= 1
                prev_char = json[i - 1] #substr(json, i - 1, 1)

                if prev_char != '{' &&  prev_char != '['
                  # If this character is the end of an element,
                  # output a new line and indent the next line
                  result << new_line

                  for j in 0..(pos - 1)
                    result << indent_str
                  end
                else
                  # Collapse empty {} and []
                  result.rstrip!
                end
              end
            end

            result << char

            if options & JSON_PRETTY_PRINT === JSON_PRETTY_PRINT
              # If the last character was the beginning of an element,
              # output a new line and indent the next line
              if char === ',' || char === '{' || char === '['
                result << new_line
                pos += 1 if char === '{' || char === '['
                for j in 0..(pos - 1)
                  result << indent_str
                end
              end
            end
          end

          result
        end

        def unescape_slashes(s)
          s.gsub('\\/', '/')
        end

        def unescape_unicode(s)
          s.gsub(/\\u([\da-fA-F]{4})/) {|m| [$1].pack('H*').unpack('n*').pack('U*')}
        end

      end
    end
  end
end