# Copyright (c) 2010-2017 Minero Aoki, Kenshi Muto
#               2002-2009 Minero Aoki
#
# This program is free software.
# You can distribute or modify this program under the terms of
# the GNU LGPL, Lesser General Public License version 2.1.
# For details of the GNU LGPL, see the file "COPYING".
#

require 'review/textutils'
require 'review/exception'
require 'nkf'

module ReVIEW
  module ErrorUtils
    def init_errorutils(f)
      @errutils_file = f
      @errutils_err = false
    end

    def warn(msg)
      @logger.warn "#{location}: #{msg}"
    end

    def error(msg)
      @errutils_err = true
      raise ApplicationError, "#{location}: #{msg}"
    end

    def location
      "#{filename}:#{lineno}"
    end

    def filename
      @errutils_file.path
    end

    def lineno
      @errutils_file.lineno
    end
  end

  class Preprocessor
    include ErrorUtils

    def self.strip(f)
      buf = ''
      Strip.new(f).each { |line| buf << line.rstrip << "\n" }
      buf
    end

    class Strip
      def initialize(f)
        @f = f
      end

      def path
        @f.path
      end

      def lineno
        @f.lineno
      end

      def gets
        @f.each_line do |line|
          return "\#@\#\n" if /\A\#@/ =~ line
          return line
        end
        nil
      end

      def each
        @f.each do |line|
          yield line unless /\A\#@/ =~ line
        end
      end
    end

    def initialize(repo, param)
      @repository = repo
      @config = param
      @logger = ReVIEW.logger
    end

    def process(inf, outf)
      init_errorutils inf
      @f = outf
      begin
        preproc inf
      rescue Errno::ENOENT => err
        error err.message
      end
    end

    private

    TYPES = %w[file range].freeze

    def preproc(f)
      init_vars
      f.each_line do |line|
        case line
        when /\A\#@\#/, /\A\#\#\#\#/
          @f.print line

        when /\A\#@defvar/
          @f.print line
          direc = parse_directive(line, 2)
          defvar(*direc.args)

        when /\A\#@mapoutput/
          direc = parse_directive(line, 1, 'stderr')
          @f.print line
          get_output(expand(direc.arg), direc['stderr']).each { |out| @f.print out.string }
          skip_list f

        when /\A\#@mapfile/
          direc = parse_directive(line, 1, 'eval')
          path = expand(direc.arg)
          ent = @repository.fetch_file(path)
          ent = evaluate(path, ent) if direc['eval']
          replace_block(f, line, ent, false) # FIXME: turn off lineno: tmp

        when /\A\#@map(?:range)?/
          direc = parse_directive(line, 2, 'unindent')
          path = expand(direc.args[0])
          ent = @repository.fetch_range(path, direc.args[1]) or
            error "unknown range: #{path}: #{direc.args[1]}"
          ent = (direc['unindent'] ? unindent(ent, direc['unindent']) : ent)
          replace_block(f, line, ent, false) # FIXME: turn off lineno: tmp

        when /\A\#@end/
          error 'unbaranced #@end'

        when /\A\#@/
          op = line.slice(/@(\w+)/, 1)
          warn "unknown directive: #{line.strip}" unless known_directive?(op)
          @f.print line

        when /\A\s*\z/ # empty line
          @f.puts
        else
          @f.print line
        end
      end
    end

    KNOWN_DIRECTIVES = %w[require provide warn ok].freeze

    def known_directive?(op)
      KNOWN_DIRECTIVES.index(op)
    end

    def replace_block(f, directive_line, newlines, with_lineno)
      @f.print directive_line
      newlines.each do |line|
        print_number line.number if with_lineno
        @f.print line.string
      end
      skip_list f
    end

    def print_number(num)
      @f.printf '%4s  ', (num ? num.to_s : '')
    end

    def skip_list(f)
      begline = f.lineno
      f.each_line do |line|
        case line
        when /\A\#@end/
          @f.print line
          return nil
        when %r{\A//\}}
          warn '//} seen in list'
          @f.print line
          return nil
        when /\A\#@\w/
          warn "#{line.slice(/\A\#@\w+/)} seen in list"
          @f.print line
        when /\A\#@/
          @f.print line
        end
      end
      error "list reached end of file (beginning line = #{begline})"
    end

    class Directive
      def initialize(op, args, opts)
        @op = op
        @args = args
        @opts = opts
      end

      attr_reader :op
      attr_reader :args
      attr_reader :opts

      def arg
        @args.first
      end

      def opt
        @opts.first
      end

      def [](key)
        @opts[key]
      end
    end

    def parse_directive(line, argc, *optdecl)
      m = /\A\#@(\w+)\((.*?)\)(?:\[(.*?)\])?\z/.match(line.strip) or
        error "wrong directive: #{line.strip}"
      op = m[1]
      args = m[2].split(/,\s*/)
      opts = parse_optargs(m[3])
      return if argc == 0 and args.empty?
      if argc == -1
        # Any number of arguments are allowed.
      elsif args.size != argc
        error 'wrong arg size'
      end
      if opts
        wrong_opts = opts.keys - optdecl
        unless wrong_opts.empty?
          error "wrong option: #{wrong_opts.keys.join(' ')}"
        end
      end
      Directive.new(op, args, opts || {})
    end

    def parse_optargs(str)
      return nil unless str
      table = {}
      str.split(/,\s*/).each do |a|
        name, spec = a.split('=', 2)
        table[name] = optarg_value(spec)
      end
      table
    end

    def optarg_value(spec)
      case spec
      when 'true' then true # [name=true]
      when 'false' then false # [name=false]
      when 'nil' then nil # [name=nil]
      when nil then true # [name]
      when /^\d+$/ then $&.to_i # [name=8]
      else # [name=val]
        spec
      end
    end

    def init_vars
      @vartable = {}
    end

    def defvar(name, value)
      @vartable[name] = value
    end

    def expand(str)
      str.gsub(/\$\w+/) do |name|
        s = @vartable[name.sub('$', '')]
        s ? expand(s) : name
      end
    end

    def unindent(chunk, n)
      n = minimum_indent(chunk) unless n.is_a?(Integer)
      re = /\A#{' ' * n}/
      chunk.map { |line| line.edit { |s| s.sub(re, '') } }
    end

    INF_INDENT = 9999

    def minimum_indent(chunk)
      n = chunk.map { |line| line.empty? ? INF_INDENT : line.num_indent }.min
      n == INF_INDENT ? 0 : n
    end

    def evaluate(path, chunk)
      outputs = get_output("ruby #{path}", false).split(/\n/).map(&:strip)
      chunk.map do |line|
        if /\# \$\d+/ =~ line.string
          # map result into source.
          line.edit { |s| s.sub(/\$(\d+)/) { outputs[$1.to_i - 1] } }
        else
          line
        end
      end
    end

    require 'open3'

    def get_output(cmd, use_stderr)
      out = err = nil
      Open3.popen3(cmd) do |_stdin, stdout, stderr|
        out = stdout.readlines
        if use_stderr
          out.concat stderr.readlines
        else
          err = stderr.readlines
        end
      end
      if err and !err.empty?
        $stderr.puts '[unexpected stderr message]'
        err.each { |line| $stderr.print line }
        error 'get_output: got unexpected output'
      end
      num = 0
      out.map { |line| Line.new(num += 1, line) }
    end
  end

  class Line
    def initialize(number, string)
      @number = number
      @string = string
    end

    attr_reader :number
    attr_reader :string
    alias_method :to_s, :string

    def edit
      self.class.new(@number, yield(@string))
    end

    def empty?
      @string.strip.empty?
    end

    def num_indent
      @string.slice(/\A\s*/).size
    end
  end

  class Repository
    include TextUtils
    include ErrorUtils

    def initialize(param)
      @repository = {}
      @config = param
      @logger = ReVIEW.logger
    end

    def fetch_file(file)
      file_descripter(file)['file']
    end

    def fetch_range(file, name)
      fetch(file, 'range', name)
    end

    def fetch(file, type, name)
      table = file_descripter(file)[type] or return nil
      table[name]
    end

    private

    def file_descripter(fname)
      return @repository[fname] if @repository[fname]

      @repository[fname] = git?(fname) ? parse_git_blob(fname) : parse_file(fname)
    end

    def git?(fname)
      fname.start_with?('git|')
    end

    def parse_git_blob(g_obj)
      IO.popen('git show ' + g_obj.sub(/\Agit\|/, ''), 'r') do |f|
        init_errorutils f
        return _parse_file(f)
      end
    end

    def parse_file(fname)
      File.open(fname, 'r:BOM|utf-8') do |f|
        init_errorutils f
        return _parse_file(f)
      end
    end

    def _parse_file(f)
      whole = []
      repo = { 'file' => whole }
      curr = { 'WHOLE' => whole }
      lineno = 1
      yacchack = false # remove ';'-only lines.
      opened = [['(not opened)', '(not opened)']] * 3

      f.each do |line|
        case line
        when /(?:\A\#@|\#@@)([a-z]+)_(begin|end)\((.*)\)/
          type = check_type($1)
          direction = $2
          spec = check_spec($3)
          case direction
          when 'begin'
            key = "#{type}/#{spec}"
            error "begin x2: #{key}" if curr[key]
            (repo[type] ||= {})[spec] = curr[key] = []
          when 'end'
            curr.delete("#{type}/#{spec}") or
              error "end before begin: #{type}/#{spec}"
          else
            raise 'must not happen'
          end

        when %r{(?:\A\#@|\#@@)([a-z]+)/(\w+)\{}
          type = check_type($1)
          spec = check_spec($2)
          key = "#{type}/#{spec}"
          error "begin x2: #{key}" if curr[key]
          (repo[type] ||= {})[spec] = curr[key] = []
          opened.push [type, spec]

        when %r{(?:\A\#@|\#@@)([a-z]+)/(\w+)\}}
          type = check_type($1)
          spec = check_spec($2)
          curr.delete("#{type}/#{spec}") or
            error "end before begin: #{type}/#{spec}"
          opened.delete "#{type}/#{spec}"

        when /(?:\A\#@|\#@@)\}/
          type, spec = opened.last
          curr.delete("#{type}/#{spec}") or
            error "closed before open: #{type}/#{spec}"
          opened.pop

        when /(?:\A\#@|\#@@)yacchack/
          yacchack = true

        when /\A\#@-/ # does not increment line number.
          line = canonical($')
          curr.each_value { |list| list.push Line.new(nil, line) }

        else
          next if yacchack and line.strip == ';'
          line = canonical(line)
          curr.each_value { |list| list.push Line.new(lineno, line) }
          lineno += 1
        end
      end
      if curr.size > 1
        curr.delete 'WHOLE'
        curr.each { |range, lines| @logger.warn "#{filename}: unclosed range: #{range} (begin @#{lines.first.number})" }
        raise ApplicationError, 'ERROR'
      end

      repo
    end

    def canonical(line)
      tabwidth = @config['tabwidth'] || 8
      if tabwidth > 0
        detab(line, tabwidth).rstrip + "\n"
      else
        line
      end
    end

    def check_type(type)
      error "wrong type: #{type.inspect}" unless Preprocessor::TYPES.index(type)
      type
    end

    def check_spec(spec)
      error "wrong spec: #{spec.inspect}" unless /\A\w+\z/ =~ spec
      spec
    end
  end
end