module Oxidized
  class GitCrypt < Output
    class GitCryptError < OxidizedError; end
    begin
      require 'git'
    rescue LoadError
      raise OxidizedError, 'git not found: sudo gem install ruby-git'
    end

    attr_reader :commitref

    def initialize
      @cfg = Oxidized.config.output.gitcrypt
      @gitcrypt_cmd = "/usr/bin/git-crypt"
      @gitcrypt_init = @gitcrypt_cmd + " init"
      @gitcrypt_unlock = @gitcrypt_cmd + " unlock"
      @gitcrypt_lock = @gitcrypt_cmd + " lock"
      @gitcrypt_adduser = @gitcrypt_cmd + " add-gpg-user --trusted "
    end

    def setup
      if @cfg.empty?
        Oxidized.asetus.user.output.gitcrypt.user  = 'Oxidized'
        Oxidized.asetus.user.output.gitcrypt.email = 'o@example.com'
        Oxidized.asetus.user.output.gitcrypt.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 crypt_init repo
      repo.chdir do
        system(@gitcrypt_init)
        @cfg.users.each do |user|
          system("#{@gitcrypt_adduser} #{user}")
        end
        File.write(".gitattributes", "* filter=git-crypt diff=git-crypt\n.gitattributes !filter !diff")
        repo.add(".gitattributes")
        repo.commit("Initial commit: crypt all config files")
      end
    end

    def lock repo
      repo.chdir do
        system(@gitcrypt_lock)
      end
    end

    def unlock repo
      repo.chdir do
        system(@gitcrypt_unlock)
      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 = Git.open repo
        unlock repo
        index = repo.index
        # Empty repo ?
        empty = File.exists? index.path
        if empty
          raise 'Empty git repo'
        else
          File.read path
        end
        lock repo
      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 = Git.open repo
        unlock repo
        walker = repo.log.path(path)
        i = -1
        tab = []
        walker.each do |commit|
          hash = {}
          hash[:date] = commit.date.to_s
          hash[:oid] = commit.objectish
          hash[:author] = commit.author
          hash[:message] = commit.message
          tab[i += 1] = hash
        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 = Git.open repo
        unlock repo
        repo.gtree(oid).files[path].contents
      rescue
        'version not found'
      ensure
        lock repo
      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, path = yield_repo_and_path(node, group)
        repo = Git.open repo
        unlock repo
        commit = repo.gcommit(oid1)

        if oid2
          commit_old = repo.gcommit(oid2)
          diff = repo.diff(commit_old, commit)
          stats = [diff.stats[:files][node.name][:insertions], diff.stats[:files][node.name][:deletions]]
          diff.each do |patch|
            if /#{node.name}\s+/.match(patch.patch.to_s.lines.first)
              diff_commits = { :patch => patch.patch.to_s, :stat => stats }
              break
            end
          end
        else
          stat = commit.parents[0].diff(commit).stats
          stat = [stat[:files][node.name][:insertions], stat[:files][node.name][:deletions]]
          patch = commit.parents[0].diff(commit).patch
          diff_commits = { :patch => patch, :stat => stat }
        end
        lock repo
        diff_commits
      rescue
        'no diffs'
      ensure
        lock repo
      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
        update_repo repo, file, data, @msg, @user, @email
      rescue Git::GitExecuteError, ArgumentError => open_error
        Oxidized.logger.debug "open_error #{open_error} #{file}"
        begin
          grepo = Git.init repo
          crypt_init grepo
        rescue => create_error
          raise GitCryptError, "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
      grepo = Git.open repo
      grepo.config('user.name', user)
      grepo.config('user.email', email)
      grepo.chdir do
        unlock grepo
        File.write(file, data)
        grepo.add(file)
        if grepo.status[file].nil?
          grepo.commit(msg)
          @commitref = grepo.log(1).first.objectish
          true
        elsif !grepo.status[file].type.nil?
          grepo.commit(msg)
          @commitref = grepo.log(1).first.objectish
          true
        end
        lock grepo
      end
    end
  end
end