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

let
  inherit (lib) mkDefault mkEnableOption mkForce mkIf mkMerge mkOption types
                boolToString callPackageWith optional optionals optionalString recursiveUpdate;

  cfg = config.services.snipe-it;

  phpPackage = cfg.phpPackage.withExtensions ({ enabled, all }:
    enabled ++ (with all; [
      openssl
      pdo
      mbstring
      tokenizer
      curl
      ldap
      zip
      fileinfo
      bcmath
      gd
    ] ++ optionals useMysql [
      pdo_mysql
    ])
  );

  nginxPackage = config.services.nginx.package;

  user = cfg.user;
  group = cfg.group;

  db = cfg.database;
  useMysql = db.type == "mysql";
  useSqlite = db.type == "sqlite";

  mail = cfg.mail;

  useSSL = with cfg.nginx; (addSSL || forceSSL || onlySSL || enableACME);

  snipe-it = cfg.package.override {
    inherit (cfg) cacheDir dataDir;
    php = phpPackage; phpPackages = phpPackage.packages;
  };

  artisan = pkgs.writeShellScriptBin "snipe-it" ''
    cd ${snipe-it}
    sudo=exec
    if [[ "$USER" != ${user} ]]; then
      sudo='exec /run/wrappers/bin/sudo -u ${user}'
    fi
    $sudo ${phpPackage}/bin/php artisan $*
  '';

in {

  options.services.snipe-it = {
    enable = mkEnableOption "Snipe-IT free open source IT asset management";

    package = mkOption {
      type = types.package;
      default = callPackageWith pkgs ../../pkgs/snipe-it { };
      description = "Snipe-IT derivation to use.";
    };

    phpPackage = mkOption {
      type = types.package;
      default = pkgs.php80;
      description = "PHP package to use.";
    };

    user = mkOption {
      type = types.str;
      default = "snipe-it";
      description = "User Snipe-IT runs as.";
    };

    group = mkOption {
      type = types.str;
      default = "snipe-it";
      description = "Group Snipe-IT runs as.";
    };

    hostName = mkOption {
      type = types.str;
      example = "assets.example.com";
      description = "FQDN for the Snipe-IT instance.";
    };

    maxResults = mkOption {
      type = types.int;
      default = 500;
      description = ''
        The result limit.  This value determines the maximum number of results to return,
        even if a higher limit is passed in an API request.  This is done to prevent
        timeouts when custom scripts are requesting large numbers of assets at a time.
      '';
    };

    # Basic app settings
    appKeyFile = mkOption {
      type = types.path;
      example = "/run/keys/snipe-it-appkey";
      description = ''
        A file containing the app key.  Used for encryption where needed.
        Can be generated with <code>head -c32 /dev/urandom | base64</code>.
      '';
    };

    dataDir = mkOption {
      type = types.path;
      default = "/var/lib/snipe-it";
      description = "Snipe-IT's data directory.";
    };

    cacheDir = mkOption {
      type = types.path;
      default = "/var/cache/snipe-it";
      description = "Snipe-IT's cache directory";
    };

    database = {
      type = mkOption {
        type = types.enum [ "mysql" "sqlite" ];
        default = "mysql";
        description = "Database engine to use.";
      };
      host = mkOption {
        type = types.str;
        default = "localhost";
        description = "Database host address.";
      };
      port = mkOption {
        type = types.port;
        default = if useMysql then 3306 else 5432;
        description = ''
          Database host port.  This currently only has
          an effect when using MySQL.
        '';
      };
      name = mkOption {
        type = types.str;
        default = "snipe-it";
        description = "Name of the MySQL database.";
      };
      username = mkOption {
        type = types.str;
        default = user;
        description = "Username to use to connect to database.";
      };
      passwordFile = mkOption {
        type = types.nullOr types.path;
        example = "/run/keys/snipe-it-dbpass";
        description = ''
          File containing the password corresponding to
          <option>database.username</option>.
        '';
      };
    };

    mail = {
      host = mkOption {
        type = types.str;
        default = "localhost";
        description = "Mail server host address.";
      };
      port = mkOption {
        type = types.port;
        default = 25;
        description = "Mail server host port.";
      };
      encryption = mkOption {
        type = types.nullOr (types.enum [ "ssl" "tls" ]);
        default = null;
        example = "tls";
        description = ''
          Type of transport encryption to use.
        '';
      };
      username = mkOption {
        type = types.nullOr types.str;
        default = null;
        description = "User to use to connect to mail server.";
      };
      passwordFile = mkOption {
        type = types.path;
        example = "/run/keys/snipe-it-mailpass";
        description = ''
          File containing the password corresponding to
          <option>mail.username</option>.
        '';
      };
      fromAddress = mkOption {
        type = types.str;
        description = ''Global "From" address.'';
      };
      fromName = mkOption {
        type = types.str;
        default = "Snipe-IT";
        description = ''Global "From" name.'';
      };
      replytoAddress = mkOption {
        type = types.nullOr types.str;
        default = null;
        description = ''
          Global "Reply-To" address.  If null (the default),
          "Reply-To" won't be set.
        '';
      };
      replytoName = mkOption {
        type = types.str;
        default = "Snipe-IT";
        description = ''
          Global "Reply-To" name.  <option>mail.replytoAddress</option>
          also has to be set for this to have any effect.
        '';
      };
      autoEmbed = {
        enable = mkEnableOption "Embed images into mails instead of hyperlinking them.";

        method = mkOption {
          type = types.enum [ "attachment" "base64" ];
          default = "attachment";
          description = "Embedding method to use.";
        };
      };
    };

    memcached = {
      enable = mkEnableOption "memcached as caching backend";
      host = mkOption {
        type = types.str;
        default = "localhost";
        description = "Memcached host address.";
      };

      port = mkOption {
        type = types.port;
        default = 11211;
        description = "Memcached host port.";
      };
    };

    session = {
      lifeTime = mkOption {
        type = types.int;
        default = 12000;
        description = "Session lifetime in minutes.";
      };
      expireOnClose = mkOption {
        type = types.bool;
        default = false;
        description = "Expire sessions when closing browser window.";
      };
      encrypt = mkOption {
        type = types.bool;
        default = false;
        description = "Encrypt stored session data.";
      };
    };

    maxUploadSize = mkOption {
      type = types.str;
      default = "16M";
      example = "1G";
      description = "The maximum size for uploads (e.g. images).";
    };

    poolConfig = mkOption {
      type = with types; attrsOf (oneOf [ str int bool ]);
      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 the Snipe-IT PHP pool.  See the documentation on
        <literal>php-fpm.conf</literal> for details on configuration directives.
      '';
    };

    nginx = mkOption {
      type = types.submodule (
      recursiveUpdate
        (import
          (modulesPath + "/services/web-servers/nginx/vhost-options.nix")
          { inherit config lib; })
        {}
      );
      default = {};
      example = {
        serverAliases = [
          "snipe-it.\${config.networking.domain}"
        ];
        # To enable encryption and let letsencrypt take care of certificate
        forceSSL = true;
        enableACME = true;
      };
      description = ''
        With this option, you can customize the nginz virtualHost settings.
      '';
    };

    extraConfig = mkOption {
      type = types.nullOr types.lines;
      default = null;
      example = ''
        LOGIN_MAX_ATTEMPTS=3
        LOGIN_LOCKOUT_DURATION=300
      '';
    };

  };

  config = mkIf cfg.enable {
    warnings =
       optional (!useMysql) ''
         Please note: Using another database than MySQL isn't officially supported.
       '';

    environment.systemPackages = [ artisan ];

    services.mysql = mkIf (useMysql && db.host == "localhost") {
      enable = mkDefault true;
      package = mkDefault pkgs.mariadb;
      ensureDatabases = [ db.name ];
      ensureUsers = [{
        name = db.username;
        ensurePermissions = { "${db.name}.*" = "ALL PRIVILEGES"; };
      }];
    };

    services.phpfpm.pools.snipe-it = {
      inherit user group phpPackage;
      phpOptions = ''
        log_errors = on
        post_max_size = ${cfg.maxUploadSize}
        upload_max_filesize = ${cfg.maxUploadSize}
      '';
      settings = {
        "listen.mode" = "0660";
        "listen.owner" = user;
        "listen.group" = group;
      } // cfg.poolConfig;
    };

    services.nginx = {
      enable = mkDefault true;
      virtualHosts."${cfg.hostName}" = mkMerge [ cfg.nginx {
        root = mkForce "${snipe-it}/public";
        extraConfig = ''
          index index.php index.html index.htm;
          ${optionalString useSSL "fastcgi_param HTTPS on;"}
        '';
        locations = {
          "/" = {
            extraConfig = ''try_files $uri $uri/ /index.php$is_args$args;'';
          };
          "~ \.php$" = {
            extraConfig = ''
              try_files $uri $uri/ =404;
              include ${nginxPackage}/conf/fastcgi_params;
              fastcgi_index index.php;
              fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
              fastcgi_pass unix:${config.services.phpfpm.pools."snipe-it".socket};
              ${optionalString useSSL "fastcgi_param HTTPS on;"}
            '';
          };
        };
      }];
    };

    systemd.tmpfiles.rules = [
      "d ${cfg.cacheDir}                                      0700 ${user} ${group} - -"
      "d ${cfg.cacheDir}/bootstrap                            0700 ${user} ${group} - -"
      "d ${cfg.dataDir}                                       0710 ${user} ${group} - -"
      "d ${cfg.dataDir}/uploads                               0750 ${user} ${group} - -"
      "d ${cfg.dataDir}/uploads/accessories                   0750 ${user} ${group} - -"
      "d ${cfg.dataDir}/uploads/assets                        0750 ${user} ${group} - -"
      "d ${cfg.dataDir}/uploads/avatars                       0750 ${user} ${group} - -"
      "d ${cfg.dataDir}/uploads/barcodes                      0750 ${user} ${group} - -"
      "d ${cfg.dataDir}/uploads/categories                    0750 ${user} ${group} - -"
      "d ${cfg.dataDir}/uploads/companies                     0750 ${user} ${group} - -"
      "d ${cfg.dataDir}/uploads/components                    0750 ${user} ${group} - -"
      "d ${cfg.dataDir}/uploads/consumables                   0750 ${user} ${group} - -"
      "d ${cfg.dataDir}/uploads/departments                   0750 ${user} ${group} - -"
      "d ${cfg.dataDir}/uploads/locations                     0750 ${user} ${group} - -"
      "d ${cfg.dataDir}/uploads/manufacturers                 0750 ${user} ${group} - -"
      "d ${cfg.dataDir}/uploads/models                        0750 ${user} ${group} - -"
      "d ${cfg.dataDir}/uploads/suppliers                     0750 ${user} ${group} - -"
      "d ${cfg.dataDir}/storage                               0700 ${user} ${group} - -"
      "d ${cfg.dataDir}/storage/app                           0700 ${user} ${group} - -"
      "d ${cfg.dataDir}/storage/app/backups                   0700 ${user} ${group} - -"
      "d ${cfg.dataDir}/storage/app/backups/env-backups       0700 ${user} ${group} - -"
      "d ${cfg.dataDir}/storage/debugbar                      0700 ${user} ${group} - -"
      "d ${cfg.dataDir}/storage/framework                     0700 ${user} ${group} - -"
      "d ${cfg.dataDir}/storage/framework/cache               0700 ${user} ${group} - -"
      "d ${cfg.dataDir}/storage/framework/sessions            0700 ${user} ${group} - -"
      "d ${cfg.dataDir}/storage/framework/views               0700 ${user} ${group} - -"
      "d ${cfg.dataDir}/storage/logs                          0700 ${user} ${group} - -"
      "d ${cfg.dataDir}/storage/private_uploads               0700 ${user} ${group} - -"
      "d ${cfg.dataDir}/storage/private_uploads/assetmodels   0700 ${user} ${group} - -"
      "d ${cfg.dataDir}/storage/private_uploads/assets        0700 ${user} ${group} - -"
      "d ${cfg.dataDir}/storage/private_uploads/audits        0700 ${user} ${group} - -"
      "d ${cfg.dataDir}/storage/private_uploads/imports       0700 ${user} ${group} - -"
      "d ${cfg.dataDir}/storage/private_uploads/licenses      0700 ${user} ${group} - -"
      "d ${cfg.dataDir}/storage/private_uploads/signatures    0700 ${user} ${group} - -"
      "d ${cfg.dataDir}/storage/private_uploads/users         0700 ${user} ${group} - -"
    ] ++ optionals useSqlite [
      "f ${cfg.dataDir}/database.sqlite                       0600 ${user} ${group} -"
    ];


    systemd.services.snipe-it-setup = {
      description = "Preparation tasks for Snipe-IT";
      before = [ "phpfpm-snipe-it.service" ];
      after = optional useMysql "mysql.service";
      wantedBy = [ "multi-user.target" ];
      serviceConfig = {
        Type = "oneshot";
        User = user;
        WorkingDirectory = "${snipe-it}";
      };
      script = ''
        # create .env file
        cat > ${cfg.dataDir}/.env << EOF
        APP_KEY="base64:$(head -n1 ${cfg.appKeyFile})"
        APP_URL="http${optionalString useSSL "s"}://${cfg.hostName}"
        APP_LOG=syslog
        MAX_RESULTS=${toString cfg.maxResults}

      '' + optionalString useSSL ''
        ENABLE_HSTS=true
        SECURE_COOKIES=true

      '' + ''
        SESSION_DRIVER=file
        SESSION_LIFETIME=${toString cfg.session.lifeTime}
        EXPIRE_ON_CLOSE=${boolToString cfg.session.expireOnClose}
        ENCRYPT=${boolToString cfg.session.encrypt}

        DB_CONNECTION=${db.type}
      '' + optionalString (db.type != "sqlite") ''
        DB_HOST=${db.host}
        DB_PORT=${toString db.port}
        DB_PASSWORD="$(head -n1 ${db.passwordFile})"
        DB_USERNAME=${db.username}
        DB_DATABASE=${db.name}
      '' + ''

        MAIL_DRIVER=smtp
        MAIL_HOST=${mail.host}
        MAIL_PORT=${toString mail.port}
        ${optionalString (mail.encryption != null) "MAIL_ENCRYPTION=${mail.encryption}"}
        MAIL_FROM_ADDR=${mail.fromAddress}
        MAIL_FROM_NAME=${mail.fromName}
        MAIL_AUTO_EMBED=${boolToString mail.autoEmbed.enable}
        MAIL_AUTO_EMBED_METHOD=${mail.autoEmbed.method}
      '' + optionalString (mail.username != null) ''
        MAIL_USERNAME=${mail.username}
        MAIL_PASSWORD="$(head -n1 ${mail.passwordFile})"
      '' + optionalString (mail.replytoAddress != null) ''
        MAIL_REPLYTO_ADDR=${mail.replytoAddress}
        MAIL_REPLYTO_NAME=${mail.replytoName}
      '' + optionalString cfg.memcached.enable ''

        CACHE_DRIVER=memcached
        MEMCACHED_HOST=${cfg.memcached.host}
        MEMCACHED_PORT=${toString cfg.memcached.port}
      '' + ''

        ${optionalString (cfg.extraConfig != null) cfg.extraConfig}
        EOF
        chmod 600 ${cfg.dataDir}/.env

        # re-evaluate configuration
        ${phpPackage}/bin/php artisan config:clear
        ${phpPackage}/bin/php artisan config:cache

        # migrate db
        ${phpPackage}/bin/php artisan migrate --force

        # create caches
        ${phpPackage}/bin/php artisan event:cache
        ${phpPackage}/bin/php artisan view:cache
      '';
    };

    users = {
      users."${user}" = {
        isSystemUser = true;
        home = cfg.dataDir;
        group = group;
      };
      groups."${group}" = {};
      users."${config.services.nginx.user}".extraGroups = [ group ];
    };
  };
}