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

with lib;
let
  site = "forum.test.selby.ca";
  hostname = config.instance.hostname;
  host-secrets = config.fudo.secrets.host-secrets.${hostname};

  database-name = "forum_selby_ca";
  database-user = "forum_selby_ca";

  state-directory = "/state/selby/forum";

  password-injector-sql = csv-file: pkgs.stdenv.mkDerivation {
    name = "${site}-password-injector-sql";
    phases = [ "installPhase" ];
    buildInputs = [ pkgs.ruby ];
    installPhase = ''
      ${password-convert-script csv-file}
    '';
  };

  password-convert-script = csv-file: pkgs.writeScript "vanilla-forum-password-convert.rb" ''
    #!${pkgs.ruby}/bin/ruby

    require 'csv'

    data = CSV::readlines("${csv-file}")
    File::open(ENV["out"], "w") { |sql|
      data.each { |row|
        sql.puts("UPDATE users SET import_pass='#{row[2]}' FROM user_emails WHERE users.id = user_emails.user_id AND user_emails.email = '#{row[1]}';")
      }
    }
  '';

  head-pkgs = let
    nixos = pkgs.fetchgit {
      url = "https://github.com/nixos/nixpkgs.git";
      rev = "21.11";
      sha256 = "162dywda2dvfj1248afxc45kcrg83appjd0nmdb541hl7rnncf02";
    };
  in import "${nixos}" {
    system = pkgs.system;
    config = pkgs.config;
    overlays = pkgs.overlays;
  };

in {
  config = let
    admin-pw-file = "admin.passwd";
    db-pw-file = "database.passwd";
    data-file = "data-forum_selby_ca.txt";
  in {

    fudo = {
      secrets.host-secrets.${hostname} = let
        selby-discourse-db-password =
          pkgs.lib.passwd.stablerandom-passwd-file
            "selby-discourse-database-password"
            "selby-discourse-database-password-${config.instance.build-seed}";

        files = config.fudo.secrets.files;
      in {
        selby-discourse-database-passwd = {
          source-file = selby-discourse-db-password;
          target-file = "/run/selby/forum/${db-pw-file}";
          user = "root";
        };

        postgresql-selby-discourse-password = {
          source-file = selby-discourse-db-password;
          target-file = "/run/postgres/selby-discourse.passwd";
          user = config.services.postgresql.superUser;
        };

        selby-discourse-admin = {
          source-file = pkgs.lib.passwd.stablerandom-passwd-file
            "selby-discourse-admin"
            "selby-discourse-admin-${config.instance.build-seed}";
          target-file = "/run/selby/forum/${admin-pw-file}";
          user = "root";
        };

        selby-forum-data = {
          source-file = files.blobs."selby-forum-2021-12-14.clean";
          target-file = "/run/selby/forum/${data-file}";
          user = "root";
        };

        selby-forum-passwords-sql = {
          source-file = "${password-injector-sql files.blobs."forum_selby_ca-passwd.csv"}";
          target-file = "/run/postgres/selby/forum-passwords.sql";
          user = config.services.postgresql.superUser;
        };
      };

      postgresql = {
        databases.${database-name}.users = [ "niten" ];
        users.${database-user} = {
          password-file = host-secrets.postgresql-selby-discourse-password.target-file;
          databases.${database-name} = {
            access = "CONNECT,CREATE";
            entity-access = {
              "ALL TABLES IN SCHEMA public" = "SELECT,INSERT,UPDATE,DELETE";
              "ALL SEQUENCES IN SCHEMA public" = "SELECT,UPDATE";
            };
          };
        };
      };
    };

    ## Fuckin what why won't this cert work?
    services.nginx = {
      enable = true;

      recommendedOptimisation = true;
      recommendedGzipSettings = true;
      recommendedProxySettings = true;

      virtualHosts = {
        "${site}" = {
          enableACME = true;
          forceSSL = true;
          locations."/".proxyPass = "http://192.168.55.2:80";
        };
      };
    };

    containers.selby-forum = let
      parent-host = "192.168.55.1";
      container-host = "192.168.55.2";
    in {
      ephemeral = true;
      privateNetwork = true;
      localAddress = container-host;
      hostAddress = parent-host;
      autoStart = true;

      bindMounts = {
        "/run/selby-discourse" = {
          hostPath = "/run/selby/forum";
          isReadOnly = true;
        };
        "/var/lib/discourse" = {
          hostPath = state-directory;
          isReadOnly = false;
        };
      };

      config = { config, lib, ... }: let
        discourse-user = config.systemd.services.discourse.serviceConfig.User;
      in {
        nixpkgs.pkgs = head-pkgs;

        environment.systemPackages = with pkgs; [
          nmap
        ];

        networking.firewall.enable = false;

        services.discourse = {
          enable = true;
          hostname = site;
          enableACME = false;
          plugins = with config.services.discourse.package.plugins; [
            discourse-migratepassword
          ];
          admin = {
            username = "admin";
            fullName = "Admin";
            email = "admin@selby.ca";
            passwordFile = "/etc/selby-discourse/${admin-pw-file}";
          };
          database = {
            name = database-name;
            host = parent-host;
            username = database-user;
            passwordFile = "/etc/selby-discourse/${db-pw-file}";
          };
        };

        environment.etc = {
          "selby-discourse/${admin-pw-file}" = {
            source = "/run/selby-discourse/${admin-pw-file}";
            user = discourse-user;
            mode = "0400";
          };
          "selby-discourse/${db-pw-file}" = {
            source = "/run/selby-discourse/${db-pw-file}";
            user = discourse-user;
            mode = "0400";
          };
          "selby-discourse/${data-file}" = {
            source = "/run/selby-discourse/${data-file}";
            user = discourse-user;
            mode = "0400";
          };
        };

        systemd = {
          tmpfiles.rules = [
            "/run/discourse 750 ${discourse-user} ${discourse-user} - -"
            "/var/lib/discourse 750 ${discourse-user} ${discourse-user} - -"
          ];

          services = {
            discourse = {
              after = [ "multi-user.target" ];
            };

            discourse-import-vanilla = let
              env-without-path =
                filterAttrs (attr: _: attr != "PATH")
                  config.systemd.services.discourse.environment;
              selby-forum-data = container-selby-forum-data-file;
            in {
              description = "One-off job to import Vanilla forum.";
              path = config.systemd.services.discourse.path;
              environment = env-without-path;
              serviceConfig = {
                User = config.systemd.services.discourse.serviceConfig.User;
                Group = config.systemd.services.discourse.serviceConfig.Group;
                Type = "oneshot";
                WorkingDirectory = config.systemd.services.discourse.serviceConfig.WorkingDirectory;
                ExecStart = pkgs.writeShellScript "import-vanilla-forum.sh" ''
                  ruby script/import_scripts/vanilla.rb /etc/selby-discourse/${data-file}
                '';
              };
            };
          };
        };
      };
    };

    systemd = {
      tmpfiles.rules = [
        "d ${state-directory} 750 - - - -"
      ];

      services = {
        discourse-prepare = {
          description = "Do discourse's superuser-requiring database work for it.";
          wantedBy = [ "container@forum-selby-ca.service" ];
          before = [ "container@forum-selby-ca.service" ];
          requires = [ config.fudo.postgresql.systemd-target ];
          after = [ config.fudo.postgresql.systemd-target ];
          path = with pkgs; [ postgresql ];
          serviceConfig = {
            User = config.services.postgresql.superUser;
            ExecStart = pkgs.writeShellScript "discourse-prepare.sh" ''
              psql -d ${database-name} -c "CREATE EXTENSION IF NOT EXISTS hstore;"
              psql -d ${database-name} -c "CREATE EXTENSION IF NOT EXISTS pg_trgm;"
            '';
          };
        };

        discourse-add-password-hash = let
          alter-user-script = pkgs.writeText "create-password-column.sql" ''
            ALTER TABLE users ADD COLUMN IF NOT EXISTS import_pass VARCHAR (128);
          '';
        in {
          description = "One-off job to add user password hashes from Vanilla forum.";
          path = with pkgs; [ postgresql ];
          serviceConfig = {
            User = config.services.postgresql.superUser;
            Type = "oneshot";
            ExecStart = pkgs.writeShellScript "import-vanilla-passwords.sh" ''
              psql -d ${database-name} -f ${alter-user-script}
              psql -d ${database-name} -f ${host-secrets.selby-forum-passwords-sql.target-file}
            '';
          };
        };
      };
    };
  };
}