{
  lib,
  pkgs,
  ...
}:
let
  mockServer = pkgs.writeText "mock-server.py" ''
    import http.server, json, os, sys
    from urllib.parse import urlparse

    MODE = sys.argv[1]
    PORT = int(sys.argv[2])
    DATA_FILE = sys.argv[3]

    class Handler(http.server.BaseHTTPRequestHandler):
        def log_message(self, fmt, *args):
            pass

        def _read_body(self):
            length = int(self.headers.get("Content-Length", 0))
            return json.loads(self.rfile.read(length)) if length else {}

        def _json(self, code, body):
            data = json.dumps(body).encode()
            self.send_response(code)
            self.send_header("Content-Type", "application/json")
            self.end_headers()
            self.wfile.write(data)

        def do_GET(self):
            if MODE == "jellyfin" and self.path.startswith("/Sessions"):
                try:
                    with open(DATA_FILE) as f:
                        sessions = json.load(f)
                except Exception:
                    sessions = []
                self._json(200, sessions)
            else:
                self.send_response(404)
                self.end_headers()

        def do_POST(self):
            if MODE == "grafana" and self.path == "/api/annotations":
                body = self._read_body()
                try:
                    with open(DATA_FILE) as f:
                        annotations = json.load(f)
                except Exception:
                    annotations = []
                aid = len(annotations) + 1
                body["id"] = aid
                annotations.append(body)
                with open(DATA_FILE, "w") as f:
                    json.dump(annotations, f)
                self._json(200, {"id": aid, "message": "Annotation added"})
            else:
                self.send_response(404)
                self.end_headers()

        def do_PATCH(self):
            if MODE == "grafana" and self.path.startswith("/api/annotations/"):
                aid = int(self.path.rsplit("/", 1)[-1])
                body = self._read_body()
                try:
                    with open(DATA_FILE) as f:
                        annotations = json.load(f)
                except Exception:
                    annotations = []
                for a in annotations:
                    if a["id"] == aid:
                        a.update(body)
                with open(DATA_FILE, "w") as f:
                    json.dump(annotations, f)
                self._json(200, {"message": "Annotation patched"})
            else:
                self.send_response(404)
                self.end_headers()

    http.server.HTTPServer(("127.0.0.1", PORT), Handler).serve_forever()
  '';

  script = ../services/jellyfin-annotations.py;
  python = pkgs.python3;
in
pkgs.testers.runNixOSTest {
  name = "jellyfin-annotations";

  nodes.machine =
    { pkgs, ... }:
    {
      environment.systemPackages = [ pkgs.python3 ];
    };

  testScript = ''
    import json
    import time

    JELLYFIN_PORT = 18096
    GRAFANA_PORT  = 13000
    SESSIONS_FILE = "/tmp/sessions.json"
    ANNOTS_FILE   = "/tmp/annotations.json"
    STATE_FILE    = "/tmp/annotations-state.json"
    CREDS_DIR     = "/tmp/test-creds"
    PYTHON        = "${python}/bin/python3"
    MOCK          = "${mockServer}"
    SCRIPT        = "${script}"

    def read_annotations():
        out = machine.succeed(f"cat {ANNOTS_FILE} 2>/dev/null || echo '[]'")
        return json.loads(out.strip())

    start_all()
    machine.wait_for_unit("multi-user.target")

    with subtest("Setup mock credentials and data files"):
        machine.succeed(f"mkdir -p {CREDS_DIR} && echo 'fake-api-key' > {CREDS_DIR}/jellyfin-api-key")
        machine.succeed(f"echo '[]' > {SESSIONS_FILE}")
        machine.succeed(f"echo '[]' > {ANNOTS_FILE}")

    with subtest("Start mock Jellyfin and Grafana servers"):
        machine.succeed(
            f"systemd-run --unit=mock-jellyfin {PYTHON} {MOCK} jellyfin {JELLYFIN_PORT} {SESSIONS_FILE}"
        )
        machine.succeed(
            f"systemd-run --unit=mock-grafana {PYTHON} {MOCK} grafana {GRAFANA_PORT} {ANNOTS_FILE}"
        )
        machine.wait_until_succeeds(
            f"curl -sf http://127.0.0.1:{JELLYFIN_PORT}/Sessions", timeout=10
        )
        machine.wait_until_succeeds(
            f"curl -sf -X POST http://127.0.0.1:{GRAFANA_PORT}/api/annotations "
            f"-H 'Content-Type: application/json' -d '{{\"text\":\"ping\",\"tags\":[]}}' | grep -q id",
            timeout=10,
        )
        machine.succeed(f"echo '[]' > {ANNOTS_FILE}")

    with subtest("Start annotation service pointing at mock servers"):
        machine.succeed(
            f"systemd-run --unit=annotations-svc "
            f"--setenv=JELLYFIN_URL=http://127.0.0.1:{JELLYFIN_PORT} "
            f"--setenv=GRAFANA_URL=http://127.0.0.1:{GRAFANA_PORT} "
            f"--setenv=CREDENTIALS_DIRECTORY={CREDS_DIR} "
            f"--setenv=STATE_FILE={STATE_FILE} "
            f"--setenv=POLL_INTERVAL=3 "
            f"{PYTHON} {SCRIPT}"
        )
        time.sleep(2)

    with subtest("No annotations pushed when no streams active"):
        time.sleep(4)
        annots = read_annotations()
        assert annots == [], f"Expected no annotations, got: {annots}"

    with subtest("Annotation created when stream starts"):
        machine.succeed(
            f"""echo '[{{"Id":"sess-1","UserName":"alice","NowPlayingItem":{{"Name":"Inception","Type":"Movie"}}}}]' > {SESSIONS_FILE}"""
        )
        machine.wait_until_succeeds(
            f"cat {ANNOTS_FILE} | python3 -c \"import sys,json; a=json.load(sys.stdin); exit(0 if a else 1)\"",
            timeout=15,
        )
        annots = read_annotations()
        assert len(annots) == 1, f"Expected 1 annotation, got: {annots}"
        assert annots[0]["text"] == "alice: Inception (movie)", f"Unexpected label: {annots[0]}"
        assert "jellyfin" in annots[0].get("tags", []), f"Missing jellyfin tag: {annots[0]}"
        assert "timeEnd" not in annots[0], f"timeEnd should not be set yet: {annots[0]}"

    with subtest("Annotation closed when stream ends"):
        machine.succeed(f"echo '[]' > {SESSIONS_FILE}")
        machine.wait_until_succeeds(
            f"cat {ANNOTS_FILE} | python3 -c \"import sys,json; a=json.load(sys.stdin); exit(0 if a and 'timeEnd' in a[0] else 1)\"",
            timeout=15,
        )
        annots = read_annotations()
        assert len(annots) == 1, f"Expected 1 annotation, got: {annots}"
        assert "timeEnd" in annots[0], f"timeEnd should be set: {annots[0]}"
        assert annots[0]["timeEnd"] > annots[0]["time"], "timeEnd should be after time"

    with subtest("Multiple concurrent streams each get their own annotation"):
        machine.succeed(f"echo '[]' > {ANNOTS_FILE}")
        machine.succeed(
            f"""echo '[
              {{"Id":"sess-2","UserName":"bob","NowPlayingItem":{{"Name":"Breaking Bad","SeriesName":"Breaking Bad","ParentIndexNumber":1,"IndexNumber":1}}}},
              {{"Id":"sess-3","UserName":"carol","NowPlayingItem":{{"Name":"Inception","Type":"Movie"}}}}
            ]' > {SESSIONS_FILE}"""
        )
        machine.wait_until_succeeds(
            f"cat {ANNOTS_FILE} | python3 -c \"import sys,json; a=json.load(sys.stdin); exit(0 if len(a)==2 else 1)\"",
            timeout=15,
        )
        annots = read_annotations()
        assert len(annots) == 2, f"Expected 2 annotations, got: {annots}"
        labels = sorted(a["text"] for a in annots)
        assert labels[0] == "bob: Breaking Bad S01E01 - Breaking Bad", f"Unexpected: {labels[0]}"
        assert labels[1] == "carol: Inception (movie)", f"Unexpected: {labels[1]}"

    with subtest("State survives service restart (no duplicate annotations)"):
        machine.succeed("systemctl stop annotations-svc || true")
        time.sleep(1)
        machine.succeed(
            f"systemd-run --unit=annotations-svc-2 "
            f"--setenv=JELLYFIN_URL=http://127.0.0.1:{JELLYFIN_PORT} "
            f"--setenv=GRAFANA_URL=http://127.0.0.1:{GRAFANA_PORT} "
            f"--setenv=CREDENTIALS_DIRECTORY={CREDS_DIR} "
            f"--setenv=STATE_FILE={STATE_FILE} "
            f"--setenv=POLL_INTERVAL=3 "
            f"{PYTHON} {SCRIPT}"
        )
        time.sleep(6)
        annots = read_annotations()
        assert len(annots) == 2, f"Restart should not create duplicates, got: {annots}"
  '';
}