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

with lib;

let
  cfg = config.services.forgejo;
in {
  options.services.forgejo = {
    enable = mkEnableOption "Forgejo Git server";

    domain = mkOption {
      type = types.str;
      example = "git.example.com";
      description = "The domain name for Forgejo";
    };

    stateDir = mkOption {
      type = types.str;
      default = "/var/lib/forgejo";
      description = "Directory for Forgejo data";
    };

    database = {
      createLocally = mkOption {
        type = types.bool;
        default = true;
        description = "Whether to create a local PostgreSQL database";
      };

      passwordFile = mkOption {
        type = types.nullOr types.path;
        default = null;
        example = "/run/keys/forgejo-db";
        description = "Path to file containing database password";
      };
    };

    mailer = {
      enable = mkOption {
        type = types.bool;
        default = false;
        description = "Enable email notifications";
      };

      host = mkOption {
        type = types.str;
        example = "smtp.gmail.com";
        description = "SMTP server hostname";
      };

      port = mkOption {
        type = types.port;
        default = 587;
        description = "SMTP server port";
      };

      from = mkOption {
        type = types.str;
        example = "git@example.com";
        description = "Email sender address";
      };

      userFile = mkOption {
        type = types.path;
        example = "/run/keys/forgejo-smtp-user";
        description = "Path to file containing SMTP username";
      };

      passwordFile = mkOption {
        type = types.path;
        example = "/run/keys/forgejo-smtp-pass";
        description = "Path to file containing SMTP password";
      };
    };

    oauth2 = {
      enable = mkOption {
        type = types.bool;
        default = false;
        description = "Enable OAuth2 authentication";
      };

      github = {
        enable = mkOption {
          type = types.bool;
          default = false;
          description = "Enable GitHub OAuth2 provider";
        };

        clientId = mkOption {
          type = types.str;
          description = "GitHub OAuth client ID";
        };

        clientSecret = mkOption {
          type = types.path;
          description = "Path to GitHub OAuth client secret";
        };
      };
    };

    lfs = {
      enable = mkOption {
        type = types.bool;
        default = true;
        description = "Enable Git LFS support";
      };

      storage = mkOption {
        type = types.str;
        default = "/var/lib/forgejo/lfs";
        description = "Path to LFS storage";
      };
    };

    backup = {
      enable = mkOption {
        type = types.bool;
        default = true;
        description = "Enable automated backups";
      };

      interval = mkOption {
        type = types.str;
        default = "daily";
        description = "Backup interval (systemd timer format)";
      };

      retentionDays = mkOption {
        type = types.int;
        default = 7;
        description = "Number of backups to keep";
      };

      backupDir = mkOption {
        type = types.str;
        default = "/var/backups/forgejo";
        description = "Directory to store backups";
      };
    };
  };

  config = mkIf cfg.enable {
    # PostgreSQL database
    services.postgresql = mkIf cfg.database.createLocally {
      enable = true;
      enableTCPIP = false;
      ensureDatabases = [ "forgejo" ];
      ensureUsers = [
        {
          name = "forgejo";
          ensureDBOwnership = true;
        }
      ];
    };

    # Forgejo service
    services.forgejo = {
      enable = true;
      settings = {
        server = {
          HTTP_PORT = 3000;
          DOMAIN = cfg.domain;
          ROOT_URL = "https://${cfg.domain}/";
          DISABLE_SSH = false;
          SSH_PORT = 22;
          LFS_START_SERVER = cfg.lfs.enable;
          LFS_CONTENT_PATH = cfg.lfs.storage;
        };

        database = {
          DB_TYPE = "postgres";
          HOST = "/run/postgresql";
          NAME = "forgejo";
          USER = "forgejo";
          PASSWD = mkIf (cfg.database.passwordFile != null) "#dbpass#";
        };

        service = {
          DISABLE_REGISTRATION = false;
          REQUIRE_SIGNIN_VIEW = false;
          ENABLE_NOTIFY_MAIL = cfg.mailer.enable;
        };

        mailer = mkIf cfg.mailer.enable {
          ENABLED = true;
          FROM = cfg.mailer.from;
          SMTP_ADDR = cfg.mailer.host;
          SMTP_PORT = toString cfg.mailer.port;
          USER = "#smtpuser#";
          PASSWD = "#smtppass#";
          PROTOCOL = "smtps";
        };

        session = {
          COOKIE_SECURE = true;
          COOKIE_SAMESITE = "strict";
        };

        security = {
          INSTALL_LOCK = true;
          PASSWORD_CHECK_PWN = true;
          PASSWORD_COMPLEXITY = "lower,digit"
        };
      };
    };

    # Set database password from file
    systemd.services.forgejo = {
      serviceConfig = mkMerge [
        (mkIf (cfg.database.passwordFile != null) {
          EnvironmentFile = cfg.database.passwordFile;
        })
        (mkIf cfg.mailer.enable {
          EnvironmentFile = [ cfg.mailer.userFile cfg.mailer.passwordFile ];
        })
      ];
    };

    # Nginx reverse proxy
    services.nginx = {
      enable = true;
      recommendedGzipSettings = true;
      recommendedOptimisation = true;
      recommendedProxySettings = true;
      recommendedTlsSettings = true;

      virtualHosts.${cfg.domain} = {
        forceSSL = true;
        enableACME = true;

        locations."/".proxyPass = "http://localhost:3000";

        # Proxy for WebSocket
        locations."/" = {
          proxyPass = "http://localhost:3000";
          proxyWebsockets = true;
          extraConfig = ''
            proxy_buffering off;
            proxy_read_timeout 86400;
          '';
        };

        # Proxy for LFS
        locations."/.git/info/lfs" = {
          proxyPass = "http://localhost:3000";
          extraConfig = ''
            client_max_body_size 0;
          '';
        };
      };
    };

    # Firewall
    networking.firewall = {
      allowedTCPPorts = [ 80 443 ];
      allowedUDPPorts = [ 443 ];
    };

    # Backup service
    systemd.services.forgejo-backup = mkIf cfg.backup.enable {
      description = "Forgejo backup service";
      serviceConfig = {
        Type = "oneshot";
        User = "forgejo";
        Group = "forgejo";
        WorkingDirectory = cfg.stateDir;
        ExecStart = "${pkgs.forgejo}/bin/forgejo dump --type zip --file ${cfg.backup.backupDir}/forgejo-backup-%Y-%m-%d.zip";
      };
    };

    systemd.timers.forgejo-backup = mkIf cfg.backup.enable {
      description = "Forgejo backup timer";
      wantedBy = [ "timers.target" ];
      timerConfig = {
        OnCalendar = cfg.backup.interval;
        Persistent = true;
      };
    };

    # Backup cleanup
    systemd.services.forgejo-backup-cleanup = mkIf cfg.backup.enable {
      description = "Clean up old Forgejo backups";
      serviceConfig = {
        Type = "oneshot";
        User = "root";
        ExecStart = pkgs.writeShellScript "forgejo-backup-cleanup" ''
          find ${cfg.backup.backupDir} -name "forgejo-backup-*.zip" -mtime +${toString cfg.backup.retentionDays} -delete
        '';
      };
    };

    systemd.timers.forgejo-backup-cleanup = mkIf cfg.backup.enable {
      description = "Forgejo backup cleanup timer";
      wantedBy = [ "timers.target" ];
      timerConfig = {
        OnCalendar = "weekly";
        Persistent = true;
      };
    };

    # Create backup directory
    system.activationScripts.forgejo-backup-dir = ''
      mkdir -p ${cfg.backup.backupDir}
      chown forgejo:forgejo ${cfg.backup.backupDir}
      chmod 750 ${cfg.backup.backupDir}
    '';

    # Add Forgejo to known services
    environment.systemPackages = with pkgs; [
      forgejo
    ];
  };
}