require 'tempfile'

module Git
  
  class GitExecuteError < StandardError 
  end
  
  class Lib
      
    def initialize(base = nil, logger = nil)
      @git_dir = nil
      @git_index_file = nil
      @git_work_dir = nil
      @path = nil
      
      if base.is_a?(Git::Base)
        @git_dir = base.repo.path
        @git_index_file = base.index.path if base.index
        @git_work_dir = base.dir.path if base.dir
      elsif base.is_a?(Hash)
        @git_dir = base[:repository]
        @git_index_file = base[:index] 
        @git_work_dir = base[:working_directory]
      end
      @logger = logger
    end

    # creates or reinitializes the repository
    #
    # options:
    #   :bare
    #   :working_directory
    #
    def init(opts={})
      arr_opts = []
      arr_opts << '--bare' if opts[:bare]

      command('init', arr_opts, false)
    end
    
    # tries to clone the given repo
    #
    # returns {:repository} (if bare)
    #         {:working_directory} otherwise
    #
    # accepts options:
    #  :remote::    name of remote (rather than 'origin')
    #  :bare::      no working directory
    #  :recursive:: after the clone is created, initialize all submodules within, using their default settings.
    #  :depth::     the number of commits back to pull
    # 
    # TODO - make this work with SSH password or auth_key
    #
    def clone(repository, name, opts = {})
      @path = opts[:path] || '.'
      clone_dir = opts[:path] ? File.join(@path, name) : name
      
      arr_opts = []
      arr_opts << "--bare" if opts[:bare]
      arr_opts << "--recursive" if opts[:recursive]
      arr_opts << "-o" << opts[:remote] if opts[:remote]
      arr_opts << "--depth" << opts[:depth].to_i if opts[:depth] && opts[:depth].to_i > 0
      arr_opts << "--config" << opts[:config] if opts[:config]

      arr_opts << '--'
      arr_opts << repository
      arr_opts << clone_dir
      
      command('clone', arr_opts)
      
      opts[:bare] ? {:repository => clone_dir} : {:working_directory => clone_dir}
    end
    
    
    ## READ COMMANDS ##
    
    def log_commits(opts={})
      arr_opts = log_common_options(opts)
    
      arr_opts << '--pretty=oneline'
     
      arr_opts += log_path_options(opts)

      command_lines('log', arr_opts, true).map { |l| l.split.first }
    end
    
    def full_log_commits(opts={})
      arr_opts = log_common_options(opts)
    
      arr_opts << '--pretty=raw'
      arr_opts << "--skip=#{opts[:skip]}" if opts[:skip]
   
      arr_opts += log_path_options(opts)
      
      full_log = command_lines('log', arr_opts, true)
      process_commit_data(full_log)
    end


    
    def revparse(string)
      return string if string =~ /[A-Fa-f0-9]{40}/  # passing in a sha - just no-op it
      rev = ['head', 'remotes', 'tags'].map do |d|
        File.join(@git_dir, 'refs', d, string)
      end.find do |path|
        File.file?(path)
      end
      return File.read(rev).chomp if rev
      command('rev-parse', string)
    end
    
    def namerev(string)
      command('name-rev', string).split[1]
    end
    
    def object_type(sha)
      command('cat-file', ['-t', sha])
    end
    
    def object_size(sha)
      command('cat-file', ['-s', sha]).to_i
    end
    
    # returns useful array of raw commit object data
    def commit_data(sha)
      sha = sha.to_s
      cdata = command_lines('cat-file', ['commit', sha])
      process_commit_data(cdata, sha, 0)
    end
    
    def process_commit_data(data, sha = nil, indent = 4)
      in_message = false
            
      if sha
        hsh = {'sha' => sha, 'message' => '', 'parent' => []}
      else
        hsh_array = []        
      end
    
      data.each do |line|
        line = line.chomp
        if line == ''
          in_message = !in_message
        elsif in_message
          hsh['message'] << line[indent..-1] << "\n"
        else
          data = line.split
          key = data.shift
          value = data.join(' ')
          if key == 'commit'
            sha = value
            hsh_array << hsh if hsh
            hsh = {'sha' => sha, 'message' => '', 'parent' => []}
          end
          if key == 'parent'
            hsh[key] << value
          else
            hsh[key] = value
          end
        end
      end
      
      if hsh_array
        hsh_array << hsh if hsh
        hsh_array
      else
        hsh
      end
    end
    
    def object_contents(sha, &block)
      command('cat-file', ['-p', sha], &block)
    end

    def ls_tree(sha)
      data = {'blob' => {}, 'tree' => {}}
      
      command_lines('ls-tree', sha).each do |line|
        (info, filenm) = line.split("\t")
        (mode, type, sha) = info.split
        data[type][filenm] = {:mode => mode, :sha => sha}
      end
      
      data
    end

    def mv(file1, file2)
      command_lines('mv', ['--', file1, file2])
    end
        
    def full_tree(sha)
      command_lines('ls-tree', ['-r', sha])
    end
            
    def tree_depth(sha)
      full_tree(sha).size
    end

    def change_head_branch(branch_name)
      command('symbolic-ref', ['HEAD', "refs/heads/#{branch_name}"])
    end
    
    def branches_all
      arr = []
      command_lines('branch', '-a').each do |b| 
        current = (b[0, 2] == '* ')
        arr << [b.gsub('* ', '').strip, current]
      end
      arr
    end

    def list_files(ref_dir)
      dir = File.join(@git_dir, 'refs', ref_dir)
      files = []
      Dir.chdir(dir) { files = Dir.glob('**/*').select { |f| File.file?(f) } } rescue nil
      files
    end
    
    def branch_current
      branches_all.select { |b| b[1] }.first[0] rescue nil
    end


    # returns hash
    # [tree-ish] = [[line_no, match], [line_no, match2]]
    # [tree-ish] = [[line_no, match], [line_no, match2]]
    def grep(string, opts = {})
      opts[:object] ||= 'HEAD'

      grep_opts = ['-n']
      grep_opts << '-i' if opts[:ignore_case]
      grep_opts << '-v' if opts[:invert_match]
      grep_opts << '-e'
      grep_opts << string
      grep_opts << opts[:object] if opts[:object].is_a?(String)
      grep_opts << '--' << opts[:path_limiter] if opts[:path_limiter].is_a? String

      hsh = {}
      command_lines('grep', grep_opts).each do |line|
        if m = /(.*)\:(\d+)\:(.*)/.match(line)        
          hsh[m[1]] ||= []
          hsh[m[1]] << [m[2].to_i, m[3]] 
        end
      end
      hsh
    end
    
    def diff_full(obj1 = 'HEAD', obj2 = nil, opts = {})
      diff_opts = ['-p']
      diff_opts << obj1
      diff_opts << obj2 if obj2.is_a?(String)
      diff_opts << '--' << opts[:path_limiter] if opts[:path_limiter].is_a? String

      command('diff', diff_opts)
    end
    
    def diff_stats(obj1 = 'HEAD', obj2 = nil, opts = {})
      diff_opts = ['--numstat']
      diff_opts << obj1
      diff_opts << obj2 if obj2.is_a?(String)
      diff_opts << '--' << opts[:path_limiter] if opts[:path_limiter].is_a? String

      hsh = {:total => {:insertions => 0, :deletions => 0, :lines => 0, :files => 0}, :files => {}}
      
      command_lines('diff', diff_opts).each do |file|
        (insertions, deletions, filename) = file.split("\t")
        hsh[:total][:insertions] += insertions.to_i
        hsh[:total][:deletions] += deletions.to_i
        hsh[:total][:lines] = (hsh[:total][:deletions] + hsh[:total][:insertions])
        hsh[:total][:files] += 1
        hsh[:files][filename] = {:insertions => insertions.to_i, :deletions => deletions.to_i}
      end
            
      hsh
    end

    # compares the index and the working directory
    def diff_files
      diff_as_hash('diff-files')
    end
    
    # compares the index and the repository
    def diff_index(treeish)
      diff_as_hash('diff-index', treeish)
    end
            
    def ls_files(location=nil)
      hsh = {}
      command_lines('ls-files', ['--stage', location]).each do |line|
        (info, file) = line.split("\t")
        (mode, sha, stage) = info.split
        file = eval(file) if file =~ /^\".*\"$/ # This takes care of quoted strings returned from git
        hsh[file] = {:path => file, :mode_index => mode, :sha_index => sha, :stage => stage}
      end
      hsh
    end


    def ignored_files
      command_lines('ls-files', ['--others', '-i', '--exclude-standard'])
    end


    def config_remote(name)
      hsh = {}
      config_list.each do |key, value|
        if /remote.#{name}/.match(key)
          hsh[key.gsub("remote.#{name}.", '')] = value
        end
      end
      hsh
    end

    def config_get(name)
      do_get = lambda do |path|
        command('config', ['--get', name])
      end

      if @git_dir
        Dir.chdir(@git_dir, &do_get)
      else
        build_list.call
      end
    end

    def global_config_get(name)
      command('config', ['--global', '--get', name], false)
    end
    
    def config_list
      build_list = lambda do |path|
        parse_config_list command_lines('config', ['--list'])
      end
      
      if @git_dir
        Dir.chdir(@git_dir, &build_list)
      else
        build_list.call
      end
    end

    def global_config_list
      parse_config_list command_lines('config', ['--global', '--list'], false)
    end
    
    def parse_config_list(lines)
      hsh = {}
      lines.each do |line|
        (key, *values) = line.split('=')
        hsh[key] = values.join('=')
      end
      hsh
    end

    def parse_config(file)
      parse_config_list command_lines('config', ['--list', '--file', file], false)
    end
    
    ## WRITE COMMANDS ##
        
    def config_set(name, value)
      command('config', [name, value])
    end

    def global_config_set(name, value)
      command('config', ['--global', name, value], false)
    end
         
    # updates the repository index using the workig dorectory content
    # 
    #    lib.add('path/to/file')
    #    lib.add(['path/to/file1','path/to/file2'])
    #    lib.add(:all => true)
    #
    # options:
    #   :all => true
    #   :force => true
    #
    # @param [String,Array] paths files paths to be added to the repository
    # @param [Hash] options
    def add(paths='.',options={})
      arr_opts = []
      
      arr_opts << '--all' if options[:all]
      arr_opts << '--force' if options[:force]

      arr_opts << '--' 

      arr_opts << paths
      
      arr_opts.flatten!

      command('add', arr_opts)
    end
    
    def remove(path = '.', opts = {})
      arr_opts = ['-f']  # overrides the up-to-date check by default
      arr_opts << ['-r'] if opts[:recursive]
      arr_opts << '--'
      if path.is_a?(Array)
        arr_opts += path
      else
        arr_opts << path
      end

      command('rm', arr_opts)
    end

    def commit(message, opts = {})
      arr_opts = []
      arr_opts << "--message=#{message}" if message
      arr_opts << '--amend' << '--no-edit' if opts[:amend]
      arr_opts << '--all' if opts[:add_all] || opts[:all] 
      arr_opts << '--allow-empty' if opts[:allow_empty]
      arr_opts << "--author=#{opts[:author]}" if opts[:author]
      
      command('commit', arr_opts)
    end

    def reset(commit, opts = {})
      arr_opts = []
      arr_opts << '--hard' if opts[:hard]
      arr_opts << commit if commit
      command('reset', arr_opts)
    end

    def clean(opts = {})
      arr_opts = [] 
      arr_opts << '--force' if opts[:force]
      arr_opts << '-d' if opts[:d]
      
      command('clean', arr_opts)
    end
    
    def revert(commitish, opts = {})
      # Forcing --no-edit as default since it's not an interactive session.
      opts = {:no_edit => true}.merge(opts)
      
      arr_opts = []
      arr_opts << '--no-edit' if opts[:no_edit] 
      arr_opts << commitish

      command('revert', arr_opts)
    end

    def apply(patch_file)
      arr_opts = []
      arr_opts << '--' << patch_file if patch_file
      command('apply', arr_opts)
    end
    
    def apply_mail(patch_file)
      arr_opts = []
      arr_opts << '--' << patch_file if patch_file
      command('am', arr_opts)
    end
    
    def stashes_all
      arr = []
      filename = File.join(@git_dir, 'logs/refs/stash')
      if File.exist?(filename)
        File.open(filename).each_with_index { |line, i|
          m = line.match(/:(.*)$/)
          arr << [i, m[1].strip]
        }
      end
      arr
    end
    
    def stash_save(message)
      output = command('stash save', ['--', message])
      output =~ /HEAD is now at/
    end

    def stash_apply(id = nil)
      if id
        command('stash apply', [id])
      else
        command('stash apply')
      end
    end
    
    def stash_clear
      command('stash clear')
    end
    
    def stash_list
      command('stash list')
    end
    
    def branch_new(branch)
      command('branch', branch)
    end
    
    def branch_delete(branch)
      command('branch', ['-D', branch])
    end
    
    def checkout(branch, opts = {})
      arr_opts = []
      arr_opts << '-f' if opts[:force]
      arr_opts << '-b' << opts[:new_branch] if opts[:new_branch]
      arr_opts << branch
      
      command('checkout', arr_opts)
    end

    def checkout_file(version, file)
      arr_opts = []
      arr_opts << version
      arr_opts << file
      command('checkout', arr_opts)
    end
    
    def merge(branch, message = nil)      
      arr_opts = []
      arr_opts << '-m' << message if message
      arr_opts += [branch]
      command('merge', arr_opts)
    end

    def unmerged
      unmerged = []
      command_lines('diff', ["--cached"]).each do |line|
        unmerged << $1 if line =~ /^\* Unmerged path (.*)/
      end
      unmerged
    end

    def conflicts # :yields: file, your, their
      self.unmerged.each do |f|
        your = Tempfile.new("YOUR-#{File.basename(f)}").path
        command('show', ":2:#{f}", true, "> #{escape your}") 

        their = Tempfile.new("THEIR-#{File.basename(f)}").path
        command('show', ":3:#{f}", true, "> #{escape their}") 
        yield(f, your, their)
      end
    end

    def remote_add(name, url, opts = {})
      arr_opts = ['add']
      arr_opts << '-f' if opts[:with_fetch] || opts[:fetch]
      arr_opts << '-t' << opts[:track] if opts[:track]
      arr_opts << '--'
      arr_opts << name
      arr_opts << url
      
      command('remote', arr_opts)
    end
    
    def remote_remove(name)
      command('remote', ['rm', name])
    end
    
    def remotes
      command_lines('remote')
    end

    def tags
      command_lines('tag')
    end

    def tag(tag)
      command('tag', tag)
    end

    
    def fetch(remote)
      command('fetch', remote)
    end
    
    def push(remote, branch = 'master', tags = false)
      command('push', [remote, branch])
      command('push', ['--tags', remote]) if tags
    end

		def pull(remote='origin', branch='master')
			command('pull', [remote, branch])
		end

    def tag_sha(tag_name)
      head = File.join(@git_dir, 'refs', 'tags', tag_name)
      return File.read(head).chomp if File.exists?(head)
      
      command('show-ref',  ['--tags', '-s', tag_name])
    end  
    
    def repack
      command('repack', ['-a', '-d'])
    end
    
    def gc
      command('gc', ['--prune', '--aggressive', '--auto'])
    end
    
    # reads a tree into the current index file
    def read_tree(treeish, opts = {})
      arr_opts = []
      arr_opts << "--prefix=#{opts[:prefix]}" if opts[:prefix]
      arr_opts += [treeish]
      command('read-tree', arr_opts)
    end
    
    def write_tree
      command('write-tree')
    end
    
    def commit_tree(tree, opts = {})
      opts[:message] ||= "commit tree #{tree}"
      t = Tempfile.new('commit-message')
      t.write(opts[:message])
      t.close
      
      arr_opts = []
      arr_opts << tree
      arr_opts << '-p' << opts[:parent] if opts[:parent]
      arr_opts += [opts[:parents]].map { |p| ['-p', p] }.flatten if opts[:parents]
      command('commit-tree', arr_opts, true, "< #{escape t.path}")
    end
    
    def update_ref(branch, commit)
      command('update-ref', [branch, commit])
    end
    
    def checkout_index(opts = {})
      arr_opts = []
      arr_opts << "--prefix=#{opts[:prefix]}" if opts[:prefix]
      arr_opts << "--force" if opts[:force]
      arr_opts << "--all" if opts[:all]
      arr_opts << '--' << opts[:path_limiter] if opts[:path_limiter].is_a? String

      command('checkout-index', arr_opts)
    end
    
    # creates an archive file
    #
    # options
    #  :format  (zip, tar)
    #  :prefix
    #  :remote
    #  :path
    def archive(sha, file = nil, opts = {})
      opts[:format] ||= 'zip'
      
      if opts[:format] == 'tgz'
        opts[:format] = 'tar' 
        opts[:add_gzip] = true
      end
      
      file ||= Tempfile.new('archive').path
      
      arr_opts = []
      arr_opts << "--format=#{opts[:format]}" if opts[:format]
      arr_opts << "--prefix=#{opts[:prefix]}" if opts[:prefix]
      arr_opts << "--remote=#{opts[:remote]}" if opts[:remote]
      arr_opts << sha
      arr_opts << '--' << opts[:path] if opts[:path]
      command('archive', arr_opts, true, (opts[:add_gzip] ? '| gzip' : '') + " > #{escape file}")
      return file
    end

    # returns the current version of git, as an Array of Fixnums.
    def current_command_version
      output = command('version', [], false)
      version = output[/\d+\.\d+(\.\d+)+/]
      version.split('.').collect {|i| i.to_i}
    end

    def required_command_version
      [1, 6, 0, 0]
    end

    def meets_required_version?
      current_version  = self.current_command_version
      required_version = self.required_command_version

      return current_version[0] >= required_version[0] && 
             current_version[1] >= required_version[1] &&
             (current_version[2] ? current_version[2] >= required_version[2] : true) &&
             (current_version[3] ? current_version[3] >= required_version[3] : true)
    end


    private
    
    def command_lines(cmd, opts = [], chdir = true, redirect = '')
      command(cmd, opts, chdir).split("\n")
    end
    
    def command(cmd, opts = [], chdir = true, redirect = '', &block)
      ENV['GIT_DIR'] = @git_dir
      ENV['GIT_WORK_TREE'] = @git_work_dir
      ENV['GIT_INDEX_FILE'] = @git_index_file

      path = @git_work_dir || @git_dir || @path

      opts = [opts].flatten.map {|s| escape(s) }.join(' ')

      git_cmd = "git #{cmd} #{opts} #{redirect} 2>&1"

      out = nil
      if chdir && (Dir.getwd != path)
        Dir.chdir(path) { out = run_command(git_cmd, &block) } 
      else
        out = run_command(git_cmd, &block)
      end
      
      if @logger
        @logger.info(git_cmd)
        @logger.debug(out)
      end
            
      if $?.exitstatus > 0
        if $?.exitstatus == 1 && out == ''
          return ''
        end
        raise Git::GitExecuteError.new(git_cmd + ':' + out.to_s) 
      end
      out
    end

    # Takes the diff command line output (as Array) and parse it into a Hash
    #
    # @param [String] diff_command the diff commadn to be used
    # @param [Array] opts the diff options to be used
    # @return [Hash] the diff as Hash
    def diff_as_hash(diff_command, opts=[])
      command_lines(diff_command, opts).inject({}) do |memo, line|
        info, file = line.split("\t")
        mode_src, mode_dest, sha_src, sha_dest, type = info.split
        
        memo[file] = {
          :mode_index => mode_dest, 
          :mode_repo => mode_src.to_s[1, 7], 
          :path => file, 
          :sha_repo => sha_src, 
          :sha_index => sha_dest, 
          :type => type
        }

        memo
      end
    end
    
    # Returns an array holding the common options for the log commands 
    #
    # @param [Hash] opts the given options
    # @return [Array] the set of common options that the log command will use
    def log_common_options(opts)
      arr_opts = []

      arr_opts << "-#{opts[:count]}" if opts[:count]
      arr_opts << "--no-color"
      arr_opts << "--since=#{opts[:since]}" if opts[:since].is_a? String
      arr_opts << "--until=#{opts[:until]}" if opts[:until].is_a? String
      arr_opts << "--grep=#{opts[:grep]}" if opts[:grep].is_a? String
      arr_opts << "--author=#{opts[:author]}" if opts[:author].is_a? String
      arr_opts << "#{opts[:between][0].to_s}..#{opts[:between][1].to_s}" if (opts[:between] && opts[:between].size == 2)

      arr_opts
    end
    
    # Retrurns an array holding path options for the log commands
    #
    # @param [Hash] opts the given options
    # @return [Array] the set of path options that the log command will use
    def log_path_options(opts)
      arr_opts = []
     
      arr_opts << opts[:object] if opts[:object].is_a? String
      arr_opts << '--' << opts[:path_limiter] if opts[:path_limiter]

      arr_opts
    end
    
    def run_command(git_cmd, &block)
      if block_given?
        IO.popen(git_cmd, &block)
      else
        `#{git_cmd}`.chomp
      end
    end

    def escape(s)
      escaped = s.to_s.gsub('\'', '\'\\\'\'')
      %Q{"#{escaped}"}
    end

  end
end
