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

let
  cfg = config.shb.nextcloud;

  fqdn = "${cfg.subdomain}.${cfg.domain}";
in
{
  options.shb.nextcloud = {
    enable = lib.mkEnableOption "selfhostblocks.nextcloud-server";

    subdomain = lib.mkOption {
      type = lib.types.str;
      description = "Subdomain under which Nextcloud will be served.";
      example = "nextcloud";
    };

    domain = lib.mkOption {
      description = "Domain to serve Nextcloud under.";
      type = lib.types.str;
      example = "domain.com";
    };

    externalFqdn = lib.mkOption {
      description = "External fqdn used to access Nextcloud. Defaults to <subdomain>.<domain>. This should only be set if you include the port when accessing Nextcloud.";
      type = lib.types.nullOr lib.types.str;
      example = "nextcloud.domain.com:8080";
      default = null;
    };

    dataDir = lib.mkOption {
      description = "Folder where Nextcloud will store all its data.";
      type = lib.types.str;
      default = "/var/lib/nextcloud";
    };

    adminPassFile = lib.mkOption {
      type = lib.types.path;
      description = "File containing the Nextcloud admin password.";
    };

    onlyoffice = lib.mkOption {
      description = "If non null, set up an Only Office service.";
      default = null;
      type = lib.types.nullOr (lib.types.submodule {
        options = {
          subdomain = lib.mkOption {
            type = lib.types.str;
            description = "Subdomain under which Only Office will be served.";
            default = "oo";
          };

          localNetworkIPRange = lib.mkOption {
            type = lib.types.str;
            description = "Local network range, to restrict access to Open Office to only those IPs.";
            example = "192.168.1.1/24";
          };

          jwtSecretFile = lib.mkOption {
            type = lib.types.path;
            description = "File containing the JWT secret.";
          };
        };
      });
    };

    postgresSettings = lib.mkOption {
      type = lib.types.nullOr (lib.types.attrsOf lib.types.str);
      default = null;
      description = "Settings for the PostgreSQL database. Go to https://pgtune.leopard.in.ua/ and copy the generated configuration here.";
      example = lib.literalExpression ''
      {
        # From https://pgtune.leopard.in.ua/ with:

        # DB Version: 14
        # OS Type: linux
        # DB Type: dw
        # Total Memory (RAM): 7 GB
        # CPUs num: 4
        # Connections num: 100
        # Data Storage: ssd

        max_connections = "100";
        shared_buffers = "1792MB";
        effective_cache_size = "5376MB";
        maintenance_work_mem = "896MB";
        checkpoint_completion_target = "0.9";
        wal_buffers = "16MB";
        default_statistics_target = "500";
        random_page_cost = "1.1";
        effective_io_concurrency = "200";
        work_mem = "4587kB";
        huge_pages = "off";
        min_wal_size = "4GB";
        max_wal_size = "16GB";
        max_worker_processes = "4";
        max_parallel_workers_per_gather = "2";
        max_parallel_workers = "4";
        max_parallel_maintenance_workers = "2";
      }
      '';
    };

    phpFpmPoolSettings = lib.mkOption {
      type = lib.types.nullOr (lib.types.attrsOf lib.types.anything);
      description = "Settings for PHPFPM.";
      default = null;
      example = lib.literalExpression ''
      {
        "pm" = "dynamic";
        "pm.max_children" = 50;
        "pm.start_servers" = 25;
        "pm.min_spare_servers" = 10;
        "pm.max_spare_servers" = 20;
        "pm.max_spawn_rate" = 50;
        "pm.max_requests" = 50;
        "pm.process_idle_timeout" = "20s";
      }
      '';
    };

    debug = lib.mkOption {
      type = lib.types.bool;
      description = "Enable more verbose logging.";
      default = false;
      example = true;
    };

    tracing = lib.mkOption {
      type = lib.types.nullOr lib.types.str;
      description = "Enable xdebug tracing.";
      default = null;
      example = "debug_me";
    };
  };

  config = lib.mkMerge [(lib.mkIf cfg.enable {
    users.users = {
      nextcloud = {
        name = "nextcloud";
        group = "nextcloud";
        isSystemUser = true;
      };
    };

    users.groups = {
      nextcloud = {
        members = [ "backup" ];
      };
    };

    # LDAP is manually configured through
    # https://github.com/lldap/lldap/blob/main/example_configs/nextcloud.md, see also
    # https://docs.nextcloud.com/server/latest/admin_manual/configuration_user/user_auth_ldap.html
    #
    # Verify setup with:
    #  - On admin page
    #  - https://scan.nextcloud.com/
    #  - https://www.ssllabs.com/ssltest/
    # As of writing this, we got no warning on admin page and A+ on both tests.
    #
    # Content-Security-Policy is hard. I spent so much trying to fix lingering issues with .js files
    # not loading to realize those scripts are inserted by extensions. Doh.
    services.nextcloud = {
      enable = true;
      package = pkgs.nextcloud27;

      datadir = cfg.dataDir;

      hostName = fqdn;
      nginx.hstsMaxAge = 31536000; # Needs > 1 year for https://hstspreload.org to be happy

      config = {
        dbtype = "pgsql";
        adminuser = "root";
        adminpassFile = cfg.adminPassFile;
        # Not using dbpassFile as we're using socket authentication.
        defaultPhoneRegion = "US";
        trustedProxies = [ "127.0.0.1" ];
      };
      database.createLocally = true;

      # Enable caching using redis https://nixos.wiki/wiki/Nextcloud#Caching.
      configureRedis = true;
      caching.apcu = false;
      # https://docs.nextcloud.com/server/26/admin_manual/configuration_server/caching_configuration.html
      caching.redis = true;

      # Adds appropriate nginx rewrite rules.
      webfinger = true;

      # Very important for a bunch of scripts to load correctly. Otherwise you get Content-Security-Policy errors. See https://docs.nextcloud.com/server/13/admin_manual/configuration_server/harden_server.html#enable-http-strict-transport-security
      https = config.shb.ssl.enable;

      extraOptions = let
        protocol = if config.shb.ssl.enable then "https" else "http";
      in {
        "overwrite.cli.url" = "${protocol}://${fqdn}";
        "overwritehost" = if (isNull cfg.externalFqdn) then fqdn else cfg.externalFqdn;
        # 'trusted_domains' needed otherwise we get this issue https://help.nextcloud.com/t/the-polling-url-does-not-start-with-https-despite-the-login-url-started-with-https/137576/2
        # TODO: could instead set extraTrustedDomains
        "trusted_domains" = [ fqdn ];
        # TODO: could instead set overwriteProtocol
        "overwriteprotocol" = protocol; # Needed if behind a reverse_proxy
        "overwritecondaddr" = ""; # We need to set it to empty otherwise overwriteprotocol does not work.
        "debug" = cfg.debug;
        "filelocking.debug" = cfg.debug;
      };

      phpOptions = {
        # The OPcache interned strings buffer is nearly full with 8, bump to 16.
        catch_workers_output = "yes";
        display_errors = "stderr";
        error_reporting = "E_ALL & ~E_DEPRECATED & ~E_STRICT";
        expose_php = "Off";
        "opcache.enable_cli" = "1";
        "opcache.fast_shutdown" = "1";
        "opcache.interned_strings_buffer" = "16";
        "opcache.max_accelerated_files" = "10000";
        "opcache.memory_consumption" = "128";
        "opcache.revalidate_freq" = "1";
        "openssl.cafile" = "/etc/ssl/certs/ca-certificates.crt";
        short_open_tag = "Off";

        # Needed to avoid corruption per https://docs.nextcloud.com/server/21/admin_manual/configuration_server/caching_configuration.html#id2
        "redis.session.locking_enabled" = "1";
        "redis.session.lock_retries" = "-1";
        "redis.session.lock_wait_time" = "10000";
      } // lib.optionalAttrs (! (isNull cfg.tracing)) {
        # "xdebug.remote_enable" = "on";
        # "xdebug.remote_host" = "127.0.0.1";
        # "xdebug.remote_port" = "9000";
        # "xdebug.remote_handler" = "dbgp";
        "xdebug.trigger_value" = cfg.tracing;

        "xdebug.mode" = "profile,trace";
        "xdebug.output_dir" = "/var/log/xdebug";
        "xdebug.start_with_request" = "trigger";
      };

      poolSettings = lib.mkIf (! (isNull cfg.phpFpmPoolSettings)) cfg.phpFpmPoolSettings;

      phpExtraExtensions = all: [ all.xdebug ];
    };

    services.nginx.virtualHosts.${fqdn} = {
      # listen = [ { addr = "0.0.0.0"; port = 443; } ];
      sslCertificate = lib.mkIf config.shb.ssl.enable "/var/lib/acme/${cfg.domain}/cert.pem";
      sslCertificateKey = lib.mkIf config.shb.ssl.enable "/var/lib/acme/${cfg.domain}/key.pem";
      forceSSL = lib.mkIf config.shb.ssl.enable true;
    };

    environment.systemPackages = [
      # Needed for a few apps. Would be nice to avoid having to put that in the environment and instead override https://github.com/NixOS/nixpkgs/blob/261abe8a44a7e8392598d038d2e01f7b33cf26d0/nixos/modules/services/web-apps/nextcloud.nix#L1035
      pkgs.ffmpeg

      # Needed for the recognize app.
      pkgs.nodejs
    ];

    services.postgresql.settings = lib.mkIf (! (isNull cfg.postgresSettings)) cfg.postgresSettings;

    systemd.services.phpfpm-nextcloud.serviceConfig = {
      # Setup permissions needed for backups, as the backup user is member of the jellyfin group.
      UMask = lib.mkForce "0027";
    };
    systemd.services.phpfpm-nextcloud.preStart = ''
      mkdir -p /var/log/xdebug; chown -R nextcloud: /var/log/xdebug
    '';

    systemd.services.nextcloud-cron.path = [
      pkgs.perl
    ];

    # Sets up backup for Nextcloud.
    shb.backup.instances.nextcloud = {
      sourceDirectories = [
        cfg.dataDir
      ];
      excludePatterns = [".rnd"];
    };
  }) (lib.mkIf (!(isNull cfg.onlyoffice)) {
    services.onlyoffice = {
      enable = true;
      hostname = "${cfg.onlyoffice.subdomain}.${cfg.domain}";
      port = 13444;

      postgresHost = "/run/postgresql";

      jwtSecretFile = cfg.onlyoffice.jwtSecretFile;
    };

    services.nginx.virtualHosts."${cfg.onlyoffice.subdomain}.${cfg.domain}" = {
      sslCertificate = lib.mkIf config.shb.ssl.enable "/var/lib/acme/${cfg.domain}/cert.pem";
      sslCertificateKey = lib.mkIf config.shb.ssl.enable "/var/lib/acme/${cfg.domain}/key.pem";
      forceSSL = lib.mkIf config.shb.ssl.enable true;
      locations."/" = {
        extraConfig = ''
        allow ${cfg.onlyoffice.localNetworkIPRange};
        '';
      };
    };
  })];
}