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

with lib;

let
  cfg = config.services.nextcloud;

  toKeyValue = generators.toKeyValue {
    mkKeyValue = generators.mkKeyValueDefault {} " = ";
  };

  phpOptionsExtensions = ''
    ${optionalString cfg.caching.apcu "extension=${cfg.phpPackages.apcu}/lib/php/extensions/apcu.so"}
    ${optionalString cfg.caching.redis "extension=${cfg.phpPackages.redis}/lib/php/extensions/redis.so"}
    ${optionalString cfg.caching.memcached "extension=${cfg.phpPackages.memcached}/lib/php/extensions/memcached.so"}
    zend_extension = opcache.so
    opcache.enable = 1
  '';
  phpOptions = {
    upload_max_filesize = cfg.maxUploadSize;
    post_max_size = cfg.maxUploadSize;
    memory_limit = cfg.maxUploadSize;
  } // cfg.phpOptions;
  phpOptionsStr = phpOptionsExtensions + (toKeyValue phpOptions);

  occ = pkgs.writeScriptBin "nextcloud-occ" ''
    #! ${pkgs.stdenv.shell}
    cd ${pkgs.nextcloud}
    exec /run/wrappers/bin/sudo -u nextcloud \
      NEXTCLOUD_CONFIG_DIR="${cfg.home}/config" \
      ${config.services.phpfpm.phpPackage}/bin/php \
      -c ${pkgs.writeText "php.ini" phpOptionsStr}\
      occ $*
  '';

in {
  options.services.nextcloud = {
    enable = mkEnableOption "nextcloud";
    hostName = mkOption {
      type = types.str;
      description = "FQDN for the nextcloud instance.";
    };
    home = mkOption {
      type = types.str;
      default = "/var/lib/nextcloud";
      description = "Storage path of nextcloud.";
    };
    https = mkOption {
      type = types.bool;
      default = false;
      description = "Enable if there is a TLS terminating proxy in front of nextcloud.";
    };

    maxUploadSize = mkOption {
      default = "512M";
      type = types.str;
      description = ''
        Defines the upload limit for files. This changes the relevant options
        in php.ini and nginx if enabled.
      '';
    };

    skeletonDirectory = mkOption {
      default = "";
      type = types.str;
      description = ''
        The directory where the skeleton files are located. These files will be
        copied to the data directory of new users. Leave empty to not copy any
        skeleton files.
      '';
    };

    nginx.enable = mkOption {
      type = types.bool;
      default = false;
      description = ''
        Whether to enable nginx virtual host management.
        Further nginx configuration can be done by adapting <literal>services.nginx.virtualHosts.&lt;name&gt;</literal>.
        See <xref linkend="opt-services.nginx.virtualHosts"/> for further information.
      '';
    };

    webfinger = mkOption {
      type = types.bool;
      default = false;
      description = ''
        Enable this option if you plan on using the webfinger plugin.
        The appropriate nginx rewrite rules will be added to your configuration.
      '';
    };

    phpPackages = mkOption {
      type = types.attrs;
      default = pkgs.php71Packages;
      defaultText = "pkgs.php71Packages";
      description = ''
        Overridable attribute of the PHP packages set to use.  If any caching
        module is enabled, it will be taken from here.  Therefore it should
        match the version of PHP given to
        <literal>services.phpfpm.phpPackage</literal>.
      '';
    };

    phpOptions = mkOption {
      type = types.attrsOf types.str;
      default = {
        "short_open_tag" = "Off";
        "expose_php" = "Off";
        "error_reporting" = "E_ALL & ~E_DEPRECATED & ~E_STRICT";
        "display_errors" = "stderr";
        "opcache.enable_cli" = "1";
        "opcache.interned_strings_buffer" = "8";
        "opcache.max_accelerated_files" = "10000";
        "opcache.memory_consumption" = "128";
        "opcache.revalidate_freq" = "1";
        "opcache.fast_shutdown" = "1";
        "openssl.cafile" = "/etc/ssl/certs/ca-certificates.crt";
        "catch_workers_output" = "yes";
      };
      description = ''
        Options for PHP's php.ini file for nextcloud.
      '';
    };

    poolConfig = mkOption {
      type = types.lines;
      default = ''
        pm = dynamic
        pm.max_children = 32
        pm.start_servers = 2
        pm.min_spare_servers = 2
        pm.max_spare_servers = 4
        pm.max_requests = 500
      '';
      description = ''
        Options for nextcloud's PHP pool. See the documentation on <literal>php-fpm.conf</literal> for details on configuration directives.
      '';
    };

    config = {
      dbtype = mkOption {
        type = types.enum [ "sqlite" "pgsql" "mysql" ];
        default = "sqlite";
        description = "Database type.";
      };
      dbname = mkOption {
        type = types.nullOr types.str;
        default = "nextcloud";
        description = "Database name.";
      };
      dbuser = mkOption {
        type = types.nullOr types.str;
        default = "nextcloud";
        description = "Database user.";
      };
      dbpass = mkOption {
        type = types.nullOr types.str;
        default = null;
        description = ''
          Database password.  Use <literal>dbpassFile</literal> to avoid this
          being world-readable in the <literal>/nix/store</literal>.
        '';
      };
      dbpassFile = mkOption {
        type = types.nullOr types.str;
        default = null;
        description = ''
          The full path to a file that contains the database password.
        '';
      };
      dbhost = mkOption {
        type = types.nullOr types.str;
        default = "localhost";
        description = "Database host.";
      };
      dbport = mkOption {
        type = with types; nullOr (either int str);
        default = null;
        description = "Database port.";
      };
      dbtableprefix = mkOption {
        type = types.nullOr types.str;
        default = null;
        description = "Table prefix in Nextcloud database.";
      };
      adminuser = mkOption {
        type = types.str;
        default = "root";
        description = "Admin username.";
      };
      adminpass = mkOption {
        type = types.nullOr types.str;
        default = null;
        description = ''
          Admin password.  Use <literal>adminpassFile</literal> to avoid this
          being world-readable in the <literal>/nix/store</literal>.
        '';
      };
      adminpassFile = mkOption {
        type = types.nullOr types.str;
        default = null;
        description = ''
          The full path to a file that contains the admin's password.
        '';
      };

      extraTrustedDomains = mkOption {
        type = types.listOf types.str;
        default = [];
        description = ''
          Trusted domains, from which the nextcloud installation will be
          acessible.  You don't need to add
          <literal>services.nextcloud.hostname</literal> here.
        '';
      };
    };

    caching = {
      apcu = mkOption {
        type = types.bool;
        default = true;
        description = ''
          Whether to load the APCu module into PHP.
        '';
      };
      redis = mkOption {
        type = types.bool;
        default = false;
        description = ''
          Whether to load the Redis module into PHP.
          You still need to enable Redis in your config.php.
          See https://docs.nextcloud.com/server/14/admin_manual/configuration_server/caching_configuration.html
        '';
      };
      memcached = mkOption {
        type = types.bool;
        default = false;
        description = ''
          Whether to load the Memcached module into PHP.
          You still need to enable Memcached in your config.php.
          See https://docs.nextcloud.com/server/14/admin_manual/configuration_server/caching_configuration.html
        '';
      };
    };
  };

  config = mkIf cfg.enable (mkMerge [
    { assertions = let acfg = cfg.config; in [
        { assertion = !(acfg.dbpass != null && acfg.dbpassFile != null);
          message = "Please specify no more than one of dbpass or dbpassFile";
        }
        { assertion = ((acfg.adminpass != null || acfg.adminpassFile != null)
            && !(acfg.adminpass != null && acfg.adminpassFile != null));
          message = "Please specify exactly one of adminpass or adminpassFile";
        }
      ];
    }

    { systemd.timers."nextcloud-cron" = {
        wantedBy = [ "timers.target" ];
        timerConfig.OnBootSec = "5m";
        timerConfig.OnUnitActiveSec = "15m";
        timerConfig.Unit = "nextcloud-cron.service";
      };

      systemd.services = {
        "nextcloud-setup" = let
          overrideConfig = pkgs.writeText "nextcloud-config.php" ''
            <?php
            $CONFIG = [
              'apps_paths' => [
                [ 'path' => '${cfg.home}/apps', 'url' => '/apps', 'writable' => false ],
                [ 'path' => '${cfg.home}/store-apps', 'url' => '/store-apps', 'writable' => true ],
              ],
              'datadirectory' => '${cfg.home}/data',
              'skeletondirectory' => '${cfg.skeletonDirectory}',
              ${optionalString cfg.caching.apcu "'memcache.local' => '\\OC\\Memcache\\APCu',"}
              'log_type' => 'syslog',
            ];
          '';
          occInstallCmd = let
            c = cfg.config;
            adminpass = if c.adminpassFile != null
              then ''"$(<"${toString c.adminpassFile}")"''
              else ''"${toString c.adminpass}"'';
            dbpass = if c.dbpassFile != null
              then ''"$(<"${toString c.dbpassFile}")"''
              else if c.dbpass != null
              then ''"${toString c.dbpass}"''
              else null;
            installFlags = concatStringsSep " \\\n    "
              (mapAttrsToList (k: v: "${k} ${toString v}") {
              "--database" = ''"${c.dbtype}"'';
              # The following attributes are optional depending on the type of
              # database.  Those that evaluate to null on the left hand side
              # will be omitted.
              ${if c.dbname != null then "--database-name" else null} = ''"${c.dbname}"'';
              ${if c.dbhost != null then "--database-host" else null} = ''"${c.dbhost}"'';
              ${if c.dbport != null then "--database-port" else null} = ''"${toString c.dbport}"'';
              ${if c.dbuser != null then "--database-user" else null} = ''"${c.dbuser}"'';
              ${if (any (x: x != null) [c.dbpass c.dbpassFile])
                 then "--database-pass" else null} = dbpass;
              ${if c.dbtableprefix != null
                then "--database-table-prefix" else null} = ''"${toString c.dbtableprefix}"'';
              "--admin-user" = ''"${c.adminuser}"'';
              "--admin-pass" = adminpass;
              "--data-dir" = ''"${cfg.home}/data"'';
            });
          in ''
            ${occ}/bin/nextcloud-occ maintenance:install \
                ${installFlags}
          '';
          occSetTrustedDomainsCmd = concatStringsSep "\n" (imap0
            (i: v: ''
              ${occ}/bin/nextcloud-occ config:system:set trusted_domains \
                ${toString i} --value="${toString v}"
            '') ([ cfg.hostName ] ++ cfg.config.extraTrustedDomains));

        in {
          wantedBy = [ "multi-user.target" ];
          before = [ "phpfpm-nextcloud.service" ];
          script = ''
            chmod og+x ${cfg.home}
            ln -sf ${pkgs.nextcloud}/apps ${cfg.home}/
            mkdir -p ${cfg.home}/config ${cfg.home}/data ${cfg.home}/store-apps
            ln -sf ${overrideConfig} ${cfg.home}/config/override.config.php

            chown -R nextcloud:nginx ${cfg.home}/config ${cfg.home}/data ${cfg.home}/store-apps

            # Do not install if already installed
            if [[ ! -e ${cfg.home}/config/config.php ]]; then
              ${occInstallCmd}
            fi

            ${occ}/bin/nextcloud-occ upgrade

            ${occ}/bin/nextcloud-occ config:system:delete trusted_domains
            ${occSetTrustedDomainsCmd}
          '';
          serviceConfig.Type = "oneshot";
        };
        "nextcloud-cron" = {
          environment.NEXTCLOUD_CONFIG_DIR = "${cfg.home}/config";
          serviceConfig.Type = "oneshot";
          serviceConfig.User = "nextcloud";
          serviceConfig.ExecStart = "${pkgs.php}/bin/php -f ${pkgs.nextcloud}/cron.php";
        };
      };

      services.phpfpm = {
        phpOptions = phpOptionsExtensions;
        phpPackage = pkgs.php71;
        pools.nextcloud = let
          phpAdminValues = (toKeyValue
            (foldr (a: b: a // b) {}
              (mapAttrsToList (k: v: { "php_admin_value[${k}]" = v; })
                phpOptions)));
        in {
          listen = "/run/phpfpm/nextcloud";
          extraConfig = ''
            listen.owner = nginx
            listen.group = nginx
            user = nextcloud
            group = nginx
            ${cfg.poolConfig}
            env[NEXTCLOUD_CONFIG_DIR] = ${cfg.home}/config
            env[PATH] = /run/wrappers/bin:/nix/var/nix/profiles/default/bin:/run/current-system/sw/bin:/usr/bin:/bin
            ${phpAdminValues}
          '';
        };
      };

      users.extraUsers.nextcloud = {
        home = "${cfg.home}";
        group = "nginx";
        createHome = true;
      };

      environment.systemPackages = [ occ ];
    }

    (mkIf cfg.nginx.enable {
      services.nginx = {
        enable = true;
        virtualHosts = {
          "${cfg.hostName}" = {
            root = pkgs.nextcloud;
            locations = {
              "= /robots.txt" = {
                priority = 100;
                extraConfig = ''
                  allow all;
                  log_not_found off;
                  access_log off;
                '';
              };
              "/" = {
                priority = 200;
                extraConfig = "rewrite ^ /index.php$uri;";
              };
              "~ ^/store-apps" = {
                priority = 201;
                extraConfig = "root ${cfg.home};";
              };
              "= /.well-known/carddav" = {
                priority = 210;
                extraConfig = "return 301 $scheme://$host/remote.php/dav;";
              };
              "= /.well-known/caldav" = {
                priority = 210;
                extraConfig = "return 301 $scheme://$host/remote.php/dav;";
              };
              "~ ^/(?:build|tests|config|lib|3rdparty|templates|data)/" = {
                priority = 300;
                extraConfig = "deny all;";
              };
              "~ ^/(?:\\.|autotest|occ|issue|indie|db_|console)" = {
                priority = 300;
                extraConfig = "deny all;";
              };
              "~ ^/(?:index|remote|public|cron|core/ajax/update|status|ocs/v[12]|updater/.+|ocs-provider/.+)\\.php(?:$|/)" = {
                priority = 500;
                extraConfig = ''
                  include ${pkgs.nginxMainline}/conf/fastcgi.conf;
                  fastcgi_split_path_info ^(.+\.php)(/.*)$;
                  fastcgi_param PATH_INFO $fastcgi_path_info;
                  fastcgi_param HTTPS ${if cfg.https then "on" else "off"};
                  fastcgi_param modHeadersAvailable true;
                  fastcgi_param front_controller_active true;
                  fastcgi_pass unix:/run/phpfpm/nextcloud;
                  fastcgi_intercept_errors on;
                  fastcgi_request_buffering off;
                  fastcgi_read_timeout 120s;
                '';
              };
              "~ ^/(?:updater|ocs-provider)(?:$|/)".extraConfig = ''
                try_files $uri/ =404;
                index index.php;
              '';
              "~ \\.(?:css|js|woff|svg|gif)$".extraConfig = ''
                try_files $uri /index.php$uri$is_args$args;
                add_header Cache-Control "public, max-age=15778463";
                add_header X-Content-Type-Options nosniff;
                add_header X-XSS-Protection "1; mode=block";
                add_header X-Robots-Tag none;
                add_header X-Download-Options noopen;
                add_header X-Permitted-Cross-Domain-Policies none;
                access_log off;
              '';
              "~ \\.(?:png|html|ttf|ico|jpg|jpeg)$".extraConfig = ''
                try_files $uri /index.php$uri$is_args$args;
                access_log off;
              '';
            };
            extraConfig = ''
              add_header X-Content-Type-Options nosniff;
              add_header X-XSS-Protection "1; mode=block";
              add_header X-Robots-Tag none;
              add_header X-Download-Options noopen;
              add_header X-Permitted-Cross-Domain-Policies none;
              error_page 403 /core/templates/403.php;
              error_page 404 /core/templates/404.php;
              client_max_body_size ${cfg.maxUploadSize};
              fastcgi_buffers 64 4K;
              gzip on;
              gzip_vary on;
              gzip_comp_level 4;
              gzip_min_length 256;
              gzip_proxied expired no-cache no-store private no_last_modified no_etag auth;
              gzip_types application/atom+xml application/javascript application/json application/ld+json application/manifest+json application/rss+xml application/vnd.geo+json application/vnd.ms-fontobject application/x-font-ttf application/x-web-app-manifest+json application/xhtml+xml application/xml font/opentype image/bmp image/svg+xml image/x-icon text/cache-manifest text/css text/plain text/vcard text/vnd.rim.location.xloc text/vtt text/x-component text/x-cross-domain-policy;

              ${optionalString cfg.webfinger ''
                rewrite ^/.well-known/host-meta /public.php?service=host-meta last;
                rewrite ^/.well-known/host-meta.json /public.php?service=host-meta-json last;
              ''}
            '';
          };
        };
      };
    })
  ]);
}