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

# Uptime Kuma — endpoint uptime monitoring with a status-page UI.
#
# This module does two things:
#
#   1. Declares the shared homey.monitoring.monitors option that any service
#      module can contribute to.  Adding your service's URL there means it
#      automatically appears in Uptime Kuma — no manual UI work needed.
#
#   2. Runs Uptime Kuma as an OCI container and syncs the monitor list via
#      the Socket.IO API on startup using the uptime-kuma-api Python library.
#
# Example (in nextcloud.nix):
#   homey.monitoring.monitors = [{
#     name     = "Nextcloud";
#     url      = "https://nextcloud.zakobar.com/status.php";
#     interval = 60;
#   }];
#
# Auth: Authelia two_factor, admins-only (enforced in authelia.nix + caddy.nix).
#
# Volume layout:
#   <dataDir>/uptime-kuma/  → /app/data  (SQLite DB, config)
#
# Secrets consumed from sops:
#   uptime-kuma/admin_password

let
  cfg     = config.homey.uptimeKuma;
  dataDir = config.homey.storage.mountPoint;
  domain  = homeyConfig.domain;

  # Serialise the NixOS monitor list to JSON at build time.
  # The setup script reads this at runtime to know what to create.
  monitorsJson = pkgs.writeText "uptime-kuma-monitors.json"
    (builtins.toJSON config.homey.monitoring.monitors);

  # Python environment for the monitor-sync script.
  # uptime-kuma-api's transitive deps (requests, socketio, websocket-client)
  # are listed explicitly because withPackages doesn't always pull propagated
  # deps transitively in all nixpkgs versions.
  pythonEnv = pkgs.python3.withPackages (ps: [
    ps."uptime-kuma-api"
    ps.requests
    ps."python-socketio"
    ps."websocket-client"
  ]);

  # Monitor-sync script: idempotent, hash-gated, uses Socket.IO API
  syncScript = pkgs.writeText "uptime-kuma-sync.py" ''
    #!/usr/bin/env python3
    """
    Sync monitors declared in /etc/uptime-kuma/monitors.json into Uptime Kuma.

    Runs as a oneshot systemd service after podman-uptime-kuma.service.
    Tracks a hash of the monitor list so it only re-syncs when the NixOS
    config changes.

    Uptime Kuma v1 has no REST API — everything is Socket.IO.  Initial admin
    creation uses api.setup() which raises if already done (we ignore that).
    """
    import hashlib
    import json
    import os
    import sys
    import time
    import urllib.request

    MONITORS_PATH = "/etc/uptime-kuma/monitors.json"
    HASH_PATH     = "/var/lib/uptime-kuma-setup/last-hash"
    KUMA_URL      = "http://localhost:3001"
    CREDS_DIR     = os.environ.get("CREDENTIALS_DIRECTORY", "")

    def wait_for_kuma(timeout=120):
        """Wait until Uptime Kuma HTTP responds (any non-5xx — just checks it's up)."""
        deadline = time.time() + timeout
        while time.time() < deadline:
            try:
                with urllib.request.urlopen(KUMA_URL, timeout=5) as r:
                    if r.status < 500:
                        return True
            except Exception:
                pass
            time.sleep(3)
        return False

    def main():
        with open(MONITORS_PATH) as f:
            monitors = json.load(f)

        config_hash = hashlib.sha256(
            json.dumps(monitors, sort_keys=True).encode()
        ).hexdigest()

        # Skip sync if config hasn't changed
        try:
            with open(HASH_PATH) as f:
                if f.read().strip() == config_hash:
                    print("uptime-kuma-sync: config unchanged, skipping")
                    return
        except FileNotFoundError:
            pass

        password_file = os.path.join(CREDS_DIR, "uptime_kuma_password")
        with open(password_file) as f:
            password = f.read().strip()

        print("uptime-kuma-sync: waiting for Uptime Kuma to be ready...")
        if not wait_for_kuma():
            print("uptime-kuma-sync: timed out waiting for Uptime Kuma", file=sys.stderr)
            sys.exit(1)

        from uptime_kuma_api import UptimeKumaApi, MonitorType

        api = UptimeKumaApi(KUMA_URL)

        # Initial admin setup via Socket.IO — idempotent (raises if already done, ignore it)
        try:
            api.setup("admin", password)
            print("uptime-kuma-sync: initial admin user created")
        except Exception as e:
            print(f"uptime-kuma-sync: setup skipped (already configured): {e}")

        # Login
        try:
            api.login("admin", password)
        except Exception as e:
            print(f"uptime-kuma-sync: login failed: {e}", file=sys.stderr)
            api.disconnect()
            sys.exit(1)

        # Collect all configured notification IDs so every monitor gets them.
        notification_ids = [n["id"] for n in api.get_notifications()]
        if notification_ids:
            print(f"uptime-kuma-sync: attaching notifications: {notification_ids}")

        # Sync monitors: add missing, update changed
        try:
            existing = {m["name"]: m for m in api.get_monitors()}
            for m in monitors:
                keyword    = m.get("keyword")
                maxretries = m.get("maxretries", 0)
                monitor_type = MonitorType.KEYWORD if keyword else MonitorType.HTTP
                extra = {"keyword": keyword} if keyword else {}
                if m["name"] not in existing:
                    api.add_monitor(
                        type=monitor_type,
                        name=m["name"],
                        url=m["url"],
                        interval=m.get("interval", 60),
                        maxretries=maxretries,
                        notification_id_list={str(nid): True for nid in notification_ids},
                        **extra,
                    )
                    print(f"uptime-kuma-sync: created monitor: {m['name']}")
                elif (existing[m["name"]].get("url") != m["url"]
                        or existing[m["name"]].get("keyword") != keyword
                        or existing[m["name"]].get("maxretries") != maxretries):
                    api.edit_monitor(
                        existing[m["name"]]["id"],
                        type=monitor_type,
                        url=m["url"],
                        interval=m.get("interval", 60),
                        maxretries=maxretries,
                        notification_id_list={str(nid): True for nid in notification_ids},
                        **extra,
                    )
                    print(f"uptime-kuma-sync: updated monitor: {m['name']}")
        finally:
            api.disconnect()

        # Persist hash so we don't re-sync on every boot
        os.makedirs(os.path.dirname(HASH_PATH), exist_ok=True)
        with open(HASH_PATH, "w") as f:
            f.write(config_hash)
        print("uptime-kuma-sync: done")

    if __name__ == "__main__":
        main()
  '';

in
{
  # ---------------------------------------------------------------------------
  # Shared monitor-list option — declared unconditionally so any service module
  # can contribute monitors even when Uptime Kuma itself is disabled.
  # ---------------------------------------------------------------------------
  options.homey.monitoring.monitors = lib.mkOption {
    type = lib.types.listOf (lib.types.submodule {
      options = {
        name = lib.mkOption {
          type        = lib.types.str;
          description = "Display name shown in Uptime Kuma.";
        };
        url = lib.mkOption {
          type        = lib.types.str;
          description = "URL to check (HTTP/HTTPS).";
        };
        interval = lib.mkOption {
          type    = lib.types.int;
          default = 60;
          description = "Check interval in seconds.";
        };
        keyword = lib.mkOption {
          type        = lib.types.nullOr lib.types.str;
          default     = null;
          description = "If set, use a keyword monitor that checks for this string in the response body.";
        };
        maxretries = lib.mkOption {
          type        = lib.types.int;
          default     = 0;
          description = "Consecutive failures before a DOWN alert is sent. 0 = alert immediately.";
        };
      };
    });
    default     = [];
    description = ''
      List of HTTP endpoints to monitor in Uptime Kuma.
      Each service module contributes its own entries here.
    '';
  };

  options.homey.uptimeKuma = {
    enable = lib.mkEnableOption "Uptime Kuma uptime monitoring";

    image = lib.mkOption {
      type    = lib.types.str;
      default = "docker.io/louislam/uptime-kuma:1";
    };

    port = lib.mkOption {
      type    = lib.types.port;
      default = 3001;
      description = "Host port Uptime Kuma listens on (bound to 127.0.0.1).";
    };
  };

  config = lib.mkIf cfg.enable {
    # -----------------------------------------------------------------------
    # Secrets
    # -----------------------------------------------------------------------
    sops.secrets."uptime-kuma/admin_password" = { owner = "root"; };

    # -----------------------------------------------------------------------
    # Write monitor list to /etc at build time
    # -----------------------------------------------------------------------
    environment.etc."uptime-kuma/monitors.json" = {
      source = monitorsJson;
      mode   = "0444";
    };

    # -----------------------------------------------------------------------
    # Uptime Kuma container
    # -----------------------------------------------------------------------
    virtualisation.oci-containers.containers.uptime-kuma = {
      image = cfg.image;
      ports = [ "127.0.0.1:${toString cfg.port}:3001" ];

      volumes = [
        "${dataDir}/uptime-kuma:/app/data"
      ];

      # Join the homey network so monitors can reach other containers by name
      # (e.g. phpldapadmin:80) without going through the host loopback.
      extraOptions = [ "--network=homey" ];
    };

    systemd.services."podman-uptime-kuma" = {
      after    = lib.mkAfter [ "mnt-data.mount" "podman-homey-network.service" ];
      requires = lib.mkAfter [ "mnt-data.mount" "podman-homey-network.service" ];
    };

    # -----------------------------------------------------------------------
    # Monitor-sync service: runs after Uptime Kuma is up, syncs monitors
    # -----------------------------------------------------------------------
    systemd.services."uptime-kuma-sync" = {
      description = "Sync Uptime Kuma monitors from NixOS config";
      wantedBy    = [ "multi-user.target" ];
      after       = [ "podman-uptime-kuma.service" ];
      requires    = [ "podman-uptime-kuma.service" ];

      serviceConfig = {
        Type            = "oneshot";
        RemainAfterExit = true;
        LoadCredential  = "uptime_kuma_password:${config.sops.secrets."uptime-kuma/admin_password".path}";

        ExecStart = pkgs.writeShellScript "uptime-kuma-sync-runner" ''
          set -euo pipefail
          exec ${pythonEnv}/bin/python3 ${syncScript}
        '';
      };
    };

    # -----------------------------------------------------------------------
    # Uptime Kuma self-monitor
    # -----------------------------------------------------------------------
    homey.monitoring.monitors = [{
      name     = "Uptime Kuma";
      url      = "https://uptime.${domain}";
      interval = 60;
    }];
  };
}