module Oxidized
  class Git < Output
    class GitError < OxidizedError; end
    begin
      require 'rugged'
    rescue LoadError
      raise OxidizedError, 'rugged not found: sudo gem install rugged'
    end

    attr_reader :commitref

    def initialize
      @cfg = Oxidized.config.output.git
    end

    def setup
      if @cfg.empty?
        Oxidized.asetus.user.output.git.user  = 'Oxidized'
        Oxidized.asetus.user.output.git.email = 'o@example.com'
        Oxidized.asetus.user.output.git.repo = File.join(Config::Root, 'oxidized.git')
        Oxidized.asetus.save :user
        raise NoConfig, 'no output git config, edit ~/.config/oxidized/config'
      end

      if @cfg.repo.respond_to?(:each)
        @cfg.repo.each do |group, repo|
          @cfg.repo["#{group}="] = File.expand_path repo
        end
      else
        @cfg.repo = File.expand_path @cfg.repo
      end
    end

    def store file, outputs, opt = {}
      @msg   = opt[:msg]
      @user  = (opt[:user]  or @cfg.user)
      @email = (opt[:email] or @cfg.email)
      @opt   = opt
      @commitref = nil
      repo = @cfg.repo

      outputs.types.each do |type|
        type_cfg = ''
        type_repo = File.join(File.dirname(repo), type + '.git')
        outputs.type(type).each do |output|
          (type_cfg << output; next) if not output.name
          type_file = file + '--' + output.name
          if @cfg.type_as_directory?
            type_file = type + '/' + type_file
            type_repo = repo
          end
          update type_repo, type_file, output
        end
        update type_repo, file, type_cfg
      end

      update repo, file, outputs.to_cfg
    end

    def fetch node, group
      begin
        repo, path = yield_repo_and_path(node, group)
        repo = Rugged::Repository.new repo
        index = repo.index
        index.read_tree repo.head.target.tree unless repo.empty?
        repo.read(index.get(path)[:oid]).data
      rescue
        'node not found'
      end
    end

    # give a hash of all oid revision for the given node, and the date of the commit
    def version node, group
      begin
        repo, path = yield_repo_and_path(node, group)

        repo = Rugged::Repository.new repo
        walker = Rugged::Walker.new(repo)
        walker.sorting(Rugged::SORT_DATE)
        walker.push(repo.head.target)
        i = -1
        tab = []
        walker.each do |commit|
          if commit.diff(paths: [path]).size > 0
            hash = {}
            hash[:date] = commit.time.to_s
            hash[:oid] = commit.oid
            hash[:author] = commit.author
            hash[:message] = commit.message
            tab[i += 1] = hash
          end
        end
        walker.reset
        tab
      rescue
        'node not found'
      end
    end

    # give the blob of a specific revision
    def get_version node, group, oid
      begin
        repo, path = yield_repo_and_path(node, group)
        repo = Rugged::Repository.new repo
        repo.blob_at(oid, path).content
      rescue
        'version not found'
      end
    end

    # give a hash with the patch of a diff between 2 revision and the stats (added and deleted lines)
    def get_diff node, group, oid1, oid2
      begin
        diff_commits = nil
        repo, _ = yield_repo_and_path(node, group)
        repo = Rugged::Repository.new repo
        commit = repo.lookup(oid1)

        if oid2
          commit_old = repo.lookup(oid2)
          diff = repo.diff(commit_old, commit)
          diff.each do |patch|
            if /#{node.name}\s+/.match(patch.to_s.lines.first)
              diff_commits = { :patch => patch.to_s, :stat => patch.stat }
              break
            end
          end
        else
          stat = commit.parents[0].diff(commit).stat
          stat = [stat[1], stat[2]]
          patch = commit.parents[0].diff(commit).patch
          diff_commits = { :patch => patch, :stat => stat }
        end

        diff_commits
      rescue
        'no diffs'
      end
    end

    private

    def yield_repo_and_path(node, group)
      repo, path = node.repo, node.name

      if group and @cfg.single_repo?
        path = "#{group}/#{node.name}"
      end

      [repo, path]
    end

    def update repo, file, data
      return if data.empty?

      if @opt[:group]
        if @cfg.single_repo?
          file = File.join @opt[:group], file
        else
          repo = if repo.is_a?(::String)
                   File.join File.dirname(repo), @opt[:group] + '.git'
                 else
                   repo[@opt[:group]]
                 end
        end
      end

      begin
        repo = Rugged::Repository.new repo
        update_repo repo, file, data, @msg, @user, @email
      rescue Rugged::OSError, Rugged::RepositoryError => open_error
        begin
          Rugged::Repository.init_at repo, :bare
        rescue => create_error
          raise GitError, "first '#{open_error.message}' was raised while opening git repo, then '#{create_error.message}' was while trying to create git repo"
        end
        retry
      end
    end

    def update_repo repo, file, data, msg, user, email
      oid = repo.write data, :blob
      index = repo.index
      index.read_tree repo.head.target.tree unless repo.empty?

      tree_old = index.write_tree repo
      index.add :path => file, :oid => oid, :mode => 0100644
      tree_new = index.write_tree repo

      if tree_old != tree_new
        repo.config['user.name']  = user
        repo.config['user.email'] = email
        @commitref = Rugged::Commit.create(repo,
                                           :tree       => index.write_tree(repo),
                                           :message    => msg,
                                           :parents    => repo.empty? ? [] : [repo.head.target].compact,
                                           :update_ref => 'HEAD',)

        index.write
        true
      end
    end
  end
end