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

let
  federationSenders = lib.range 0 63;
  federationReceivers = lib.range 10000 10000;
  initialSyncWorkers = lib.range 10100 10100;
  syncWorkers = lib.range 10150 10150;
  streamWriters = lib.range 10200 10200;
in
{
  services.matrix-synapse = {
    enable = true;
    withJemalloc = true;

    # https://matrix-org.github.io/synapse/latest/usage/configuration/config_documentation.html
    settings = {
      server_name = "rory.gay";

      enable_registration = true;
      registration_requires_token = true;

      require_membership_for_aliases = false;
      redaction_retention_period = null;
      user_ips_max_age = null;
      allow_device_name_lookup_over_federation = true;

      federation = {
        client_timeout = "60s";
        max_short_retries = 12;
        max_short_retry_delay = "5s";
        max_long_retries = 5;
        max_long_retry_delay = "30s";
      };

      gc_min_interval = ["5m" "30m" "60m"];
      gc_thresholds = [1000 500 250];
      event_cache_size = "12000K"; #defaults to 10K
      caches = {
        global_factor = 50000.0;
        cache_entry_ttl = "24h";
        expire_caches = true;
        sync_response_cache_duration = "6h";
        cache_autotuning = {
          max_cache_memory_usage = "65536M";
          target_cache_memory_usage = "32768M";
          min_cache_ttl = "6h";
        };
      };

      # Alicia - figure this out later...
      #registration_shared_secret = builtins.exec ["cat" "/dev/urandom" "|" "tr" "-dc" "a-zA-Z0-9" "|" "fold" "-w" "256" "|" "head" "-n" "1"];
      registration_shared_secret_path = "/var/lib/matrix-synapse/registration_shared_secret.txt";
      
      listeners = [
        { 
          port = 8008;
          bind_addresses = [ "192.168.1.2" "127.0.0.1" ];
          type = "http";
          tls = false;
          x_forwarded = true;
          resources = [ {
            names = [ "client" "federation" ];
            compress = false;
          } ];
        }
        { 
          #port = 8009;
          #bind_addresses = [ "127.0.0.1" ];
          type = "http";
          #tls = false;
          #x_forwarded = true;
          path = "/run/synapse/replication-listener.sock";
          resources = [ {
            names = [ "replication" ];
            compress = false;
          } ];
        }
      ];
      dynamic_thumbnails = true;
      presence = {
        enable = true;
        update_interval = 60;
      };
      url_preview_enabled = true;
      database = {
        name = "psycopg2";
        args = {
          user = "matrix-synapse-rory-gay";
          #passwordFile = "/run/secrets/matrix-synapse-password";
          password = "somepassword";
          database = "matrix-synapse-rory-gay";
          host = "127.0.0.1";
          application_name = "matrix-synapse (rory.gay)";
          cp_min = 5;
          cp_max = 10;
          #cp_reconnect_interval = "True";
        };
      };
      app_service_config_files = [
        #"/etc/matrix-synapse/appservice-registration.yaml"
        "/var/lib/matrix-synapse/modas-registration.yaml"
      ];

      rc_message = {
        per_second = 1000;
        burst_count = 1000;
      };
      rc_login = {
        address = {
          per_second = 1000;
          burst_count = 1000;
        };
        account = {
          per_second = 1000;
          burst_count = 1000;
        };
        failed_attempts = {
          per_second = 0.1;
          burst_count = 3;
        };
      };
      rc_joins = {
        local = {
          per_second = 1000;
          burst_count = 1000;
        };
        remote = {
          per_second = 1000;
          burst_count = 1000;
        };
      };
      rc_joins_per_room = {
        per_second = 1000;
        burst_count = 1000;
      };
      rc_invites = {
        per_room = {
          per_second = 1000;
          burst_count = 1000;
        };
        per_user = {
          per_second = 1000;
          burst_count = 1000;
        };
        per_issuer = {
          per_second = 1000;
          burst_count = 1000;
        };
      };
      rc_federation = {
        window_size = 10;
        sleep_limit = 1000;
        sleep_delay = 100;
        reject_limit = 1000;
        concurrent = 100;
      };
      federation_rr_transactions_per_room_per_second = 1;

      max_image_pixels = "100M";

      ui_auth = {
        session_timeout = "1m";
      };

      login_via_existing_session = {
        enabled = true;
        require_ui_auth = true;
        token_timeout = "1y";
      };

      report_stats = false;

      user_directory = {
        enabled = true;
        search_all_users = true;
        prefer_local_users = true;
      };

      experimental_features = {
        "org.matrix.msc3026.busy_presence" = true;
        "fi.mau.msc2815" = true;
        "org.matrix.msc3881" = true;
        "org.matrix.msc3874" = true;
        "org.matrix.msc3912" = true;
      };


      redis = {
        enabled = true;
        path = "/run/redis-matrix-synapse/redis.sock";
      };


      instance_map = {
        main = { # replication listener
          #host = "127.0.0.1";
          #port = 8009;
          path = "/run/synapse/replication-listener.sock";
        };
      } // builtins.listToAttrs (map (port: {
        name = "federation_sender-${toString port}";
        value = {
          path = "/run/synapse/federation_sender-${toString port}.sock";
        };
      }) federationSenders);
      #} // builtins.listToAttrs (map (port: {
      #  name = "federation_receiver-${toString port}";
      #  value = {
      #    path = "/run/synapse/federation_receiver-${toString port}.sock";
      #  };
      #}) federationReceivers);

      # by type:
      send_federation = false;
      federation_sender_instances = map (port: "federation_sender-${toString port}") federationSenders;

    };

    ## TODO: INVESTIGATE
    # worker_listeners:
    # - type: metrics
    #   bind_address: ''
    #   port: 9101

    workers = 
    #builtins.listToAttrs (map (port: {
    #  name = "federation_receiver-${toString port}";
    #  value = {
    #    worker_app = "synapse.app.generic_worker";
    #    worker_listeners = [
    #      { 
    #        port = port;
    #        type = "http";
    #        resources = [ {
    #          names = [ "federation" ];
    #          compress = false;
    #        } ];
    #      }
    #    ];
    #  };
    #}) federationReceivers)
    builtins.listToAttrs (map (port: {
      name = "federation_sender-${toString port}";
      value = {
        worker_app = "synapse.app.generic_worker";
        worker_listeners = [ ];
      };
    }) federationSenders);
  };

    systemd.services.matrix-synapse-reg-token = {
      description = "Random registration token for Synapse.";
      before = ["matrix-synapse.service"]; # So the registration can be used by Synapse
      wantedBy = ["multi-user.target"];
      after = ["network.target"];

      script = ''

        if [ ! -f "registration_shared_secret.txt" ]
        then
          cat /dev/urandom | tr -dc a-zA-Z0-9 | fold -w 256 | head -n 1 > registration_shared_secret.txt
        else
          echo Not generating key, key exists;
        fi'';
      serviceConfig = {
        User = "matrix-synapse";
        Group = "matrix-synapse";
        WorkingDirectory = "/var/lib/matrix-synapse";
      };
    };


  services.redis = {
    package = pkgs.keydb;
    servers.matrix-synapse = {
      enable = true;
      user = "matrix-synapse";
    };
  };
  
  systemd.tmpfiles.rules = [
    "D /run/redis-matrix-synapse 0755 matrix-synapse matrix-synapse"
  ];

}