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

with config.var;

let
  ### Element (Riot) configuration
  conf = with config.var; {
      default_server_config."m.homeserver" =
        { base_url = "https://${hostname}";
          server_name = "Maxwell";
        };
      default_server_config."m.identity_server" =
        { base_url = "https://matrix.org"; };
      roomDirectory.servers = [ "matrix.org" hostname ];

      brand = "Maxwell matrix";
      defaultCountryCode = "IT";
      showLabsSettings = true;

      # Use a trusted Jitsi instance
      jitsi.preferredDomain = "jitsi.openspeed.org";
      jitsi.externalApiUrl  = "https://jitsi.openspeed.org/libs/external_api.min.js";
    };
in

{
  ### Reverse proxy locations
  services.nginx.virtualHosts."${config.var.hostname}" =
    let
      client =
        { "m.homeserver"      =  { "base_url" = "https://${config.var.hostname}"; };
          "m.identity_server" =  { "base_url" = "https://matrix.org";  };
        };
      server = { "m.server" = "${config.var.hostname}:443"; };
    in
  {
    # Needed for matrix federation
    locations."/.well-known/matrix/server".extraConfig = ''
      add_header Content-Type application/json;
      return 200 '${builtins.toJSON server}';
    '';

    # Needed for automatic homeserver
    # setup of matrix clients
    locations."/.well-known/matrix/client".extraConfig = ''
      add_header Content-Type application/json;
      add_header Access-Control-Allow-Origin *;
      return 200 '${builtins.toJSON client}';
    '';

    # Forward matrix/admin API calls to synapse
    locations."/_matrix".proxyPass = "http://localhost:8448";
    locations."/_synapse".proxyPass = "http://localhost:8448";
  };


  ### Element/Riot static location
  services.nginx.virtualHosts."riot.${config.var.hostname}" =
  { enableACME = true;
    forceSSL   = true;

    locations."/" =
      { index = "index.html";
        alias = (pkgs.element-web.override { inherit conf; }) + "/";
      };
  };


  ### Homeserver
  services.matrix-synapse = {
    enable = true;
    server_name = config.var.hostname;

    # Tell users about our TURN server
    turn_uris = [
      "turn:${config.var.hostname}:5349?transport=udp"
      "turn:${config.var.hostname}:5350?transport=udp"
      "turn:${config.var.hostname}:5349?transport=tcp"
      "turn:${config.var.hostname}:5350?transport=tcp"
    ];

    # Bind on localhost and used a reverse proxy
    listeners = [
      { bind_address = "localhost";
        port = 8448;
        type = "http";
        tls  = false;
        resources = [
          { compress = true;  names = [ "client" ] ; }
          { compress = false; names = [ "federation" ]; }
        ];
        x_forwarded = true;
      }
    ];

    # Connect to Postrges
    database_type = "psycopg2";
    database_args = {
      user     = "matrix-synapse";
      database = "matrix-synapse";
    };

    # Make logging less verbose
    logConfig = ''
       version: 1
       formatters:
           journal_fmt:
               format: '%(name)s: [%(request)s] %(message)s'
       filters:
           context:
               (): synapse.util.logcontext.LoggingContextFilter
               request: ""
       handlers:
           journal:
               class: systemd.journal.JournalHandler
               formatter: journal_fmt
               filters: [context]
               SYSLOG_IDENTIFIER: synapse
       root:
           level: WARN
           handlers: [journal]
       disable_existing_loggers: False
    '';

    allow_guest_access  = true;
    expire_access_token = true;
    event_cache_size    = "2K";
    max_upload_size     = "1000M";
    turn_user_lifetime  = "1d";

    # Needed to restrict access to the TURN
    # server to only our matrix users.
    turn_shared_secret = config.secrets.matrix.turn;
    # Needed by the register_new_matrix_user script
    registration_shared_secret = config.secrets.matrix.registration;
  };


  ### Database
  services.postgresql.enable = true;

  # Create database on the first run
  services.postgresql.initialScript = pkgs.writeText "synapse-init.sql" ''
    CREATE ROLE "matrix-synapse" WITH LOGIN PASSWORD 'synapse';
    CREATE DATABASE "matrix-synapse" WITH OWNER "matrix-synapse"
      TEMPLATE template0
      LC_COLLATE = "C"
      LC_CTYPE = "C";
  '';


  # Handles users behind a NAT,
  # needed for reliable VoIP.
  services.coturn = {
    enable = true;

    # Only allow users vouched for
    # by the Matrix server.
    lt-cred-mech       = true;
    use-auth-secret    = true;
    static-auth-secret = config.secrets.matrix.turn;

    # Use maxwell certificate for TLS
    realm = config.var.hostname;
    cert = "/var/lib/acme/${config.var.hostname}/fullchain.pem";
    pkey = "/var/lib/acme/${config.var.hostname}/key.pem";

    # Port range for TURN relaying
    min-port = 49152;
    max-port = 49999;

    # Enable TLS
    secure-stun  = true;
    no-tcp-relay = false;

    extraConfig = ''
      external-ip=${config.var.ipAddress}
      cipher-list=HIGH
      no-loopback-peers
      no-multicast-peers
      denied-peer-ip=10.0.0.0-10.255.255.255
      denied-peer-ip=192.168.0.0-192.168.255.255
      allowed-peer-ip=192.168.1.5
      user-quota=12
      total-quota=1200
      verbose=true
    '';
  };

}