{ config, pkgs, lib, ... }:

with lib;
let
  buildbot = pkgs.buildbot;
  buildbot-master-config = pkgs.writeText "buildbot-master.cfg" ''
    # -*- python -*-
    from buildbot.plugins import *

    c = BuildmasterConfig = {}

    c['slaves'] = []
    # TODO: template potential buildslaves
    # TODO: set password?
    for i in [ 'testslave' ]:
      c['slaves'].append(buildslave.BuildSlave(i, "krebspass"))

    c['protocols'] = {'pb': {'port': 9989}}

    ####### Build Inputs
    stockholm_repo = 'http://cgit.gum/stockholm'
    c['change_source'] = []
    c['change_source'].append(changes.GitPoller(
            stockholm_repo,
            workdir='stockholm-poller', branch='master',
            project='stockholm',
            pollinterval=300))

    ####### Build Scheduler
    # TODO: configure scheduler
    important_files = util.ChangeFilter(
                  project_re="^((krebs|share)/.*|Makefile|default.nix)",
                  branch='master')
    c['schedulers'] = []
    c['schedulers'].append(schedulers.SingleBranchScheduler(
                                name="all-important-files",
                                change_filter=important_files,
                                # 3 minutes stable tree
                                treeStableTimer=3*60,
                                builderNames=["runtests"]))
    c['schedulers'].append(schedulers.ForceScheduler(
                                name="force",
                                builderNames=["runtests"]))
    ###### The actual build
    factory = util.BuildFactory()
    factory.addStep(steps.Git(repourl=stockholm_repo, mode='incremental'))

    deps = [ "gnumake", "jq" ]
    factory.addStep(steps.ShellCommand(command=["nix-shell", "-p" ] + deps ))
    factory.addStep(steps.ShellCommand(env={"LOGNAME": "shared"},
                                       command=["make", "get=krebs.deploy",
                                                        "system=test-centos7"]))

    # TODO: different Builders?
    c['builders'] = []
    c['builders'].append(
        util.BuilderConfig(name="runtests",
          # TODO: only some slaves being used in builder?
          slavenames=c['slaves'],
          factory=factory))

    ####### Status of Builds
    c['status'] = []

    from buildbot.status import html
    from buildbot.status.web import authz, auth
    # TODO: configure if http is wanted
    authz_cfg=authz.Authz(
        # TODO: configure user/pw
        auth=auth.BasicAuth([("krebs","bob")]),
        gracefulShutdown = False,
        forceBuild = 'auth',
        forceAllBuilds = 'auth',
        pingBuilder = False,
        stopBuild = False,
        stopAllBuilds = False,
        cancelPendingBuild = False,
    )
    # TODO: configure nginx
    c['status'].append(html.WebStatus(http_port=8010, authz=authz_cfg))

    from buildbot.status import words
    # TODO: configure IRC Bot
    irc = words.IRC("irc.freenode.net", "krebsbuild",
                    channels=["krebs"],
                    notify_events={
                      'sucess': 1,
                      'failure': 1,
                      'exception': 1,
                      'successToFailure': 1,
                      'failureToSuccess': 1,
                    },allowForce=True)
    c['status'].append(irc)

    ####### PROJECT IDENTITY
    c['title'] = "Stockholm"
    c['titleURL'] = "http://krebsco.de"

    c['buildbotURL'] = "http://buildbot.krebsco.de/"

    ####### DB URL
    c['db'] = {
        'db_url' : "sqlite:///state.sqlite",
    }
    ${cfg.extraConfig}
    '';

  cfg = config.makefu.buildbot.master;

  api = {
    enable = mkEnableOption "Buildbot Master";

    workDir = mkOption {
      default = "/var/lib/buildbot/master";
      type = types.str;
      description = ''
        Path to build bot master directory.
        Will be created on startup.
      '';
    };

    extraConfig = mkOption {
      default = "";
      type = types.lines;
      description = ''
        extra config appended to the generated master.cfg
      '';
    };
  };

  imp = {

    users.extraUsers.buildbotMaster = {
      uid = 672626386; #genid buildbotMaster
      description = "Buildbot Master";
      home = cfg.workDir;
      createHome = false;
    };

    users.extraGroups.buildbotMaster = {
      gid = 672626386;
    };

    systemd.services.buildbotMaster = {
      description = "Buildbot Master";
      after = [ "network.target" ];
      wantedBy = [ "multi-user.target" ];
      serviceConfig = {
        PermissionsStartOnly = true;
        # TODO: maybe also prepare buildbot.tac?
        ExecStartPre = pkgs.writeScript "buildbot-master-init" ''
          #!/bin/sh
          set -efux
          workdir=${lib.shell.escape cfg.workDir}
          if [ ! -e $workdir ];then
            mkdir -p $workdir
            ${buildbot}/bin/buildbot create-master -r -l 10 -f $workdir
            chown buildbotMaster:buildbotMaster  $workdir
          fi
          # always override the master.cfg
          cp ${toString buildbot-master-config} "$workdir/master.cfg"
          # sanity
          ${buildbot}/bin/buildbot checkconfig $workdir
          # upgrade
          ${buildbot}/bin/buildbot upgrade-master $workdir
        '';
        ExecStart = "${buildbot}/bin/buildbot ${lib.shell.escape cfg.workDir}";
        PrivateTmp = "true";
        User = "buildbotMaster";
        Restart = "always";
        RestartSec = "10";
      };
    };
  };
in
{
  options.makefu.buildbot.master = api;
  config = mkIf cfg.enable imp;
}