from __future__ import annotations

import importlib
import time
from types import SimpleNamespace

import pytest
from django.db.utils import OperationalError

from apps.health import checks


class SuccessfulCursor:
    def __enter__(self):
        return self

    def __exit__(self, exc_type, exc, tb):
        return False

    def execute(self, query):
        self.query = query


class FailingCursor:
    def __enter__(self):
        return self

    def __exit__(self, exc_type, exc, tb):
        return False

    def execute(self, query):
        raise OperationalError("database unavailable")


class FakeCache:
    def __init__(self, value_to_return=None):
        self.value_to_return = value_to_return
        self.stored = {}

    def set(self, key, value, timeout=None):
        self.stored[key] = value

    def get(self, key):
        if self.value_to_return is not None:
            return self.value_to_return
        return self.stored.get(key)

    def delete(self, key):
        self.stored.pop(key, None)


@pytest.mark.django_db
def test_db_ok(monkeypatch):
    monkeypatch.setattr(checks.connection, "cursor", lambda: SuccessfulCursor())

    result = checks.check_db()

    assert result["status"] == "ok"
    assert "latency_ms" in result


@pytest.mark.django_db
def test_db_fail(monkeypatch):
    monkeypatch.setattr(checks.connection, "cursor", lambda: FailingCursor())

    result = checks.check_db()

    assert result == {"status": "fail", "detail": "database unavailable"}


@pytest.mark.django_db
def test_cache_ok(monkeypatch):
    monkeypatch.setattr(checks, "cache", FakeCache())

    result = checks.check_cache()

    assert result["status"] == "ok"
    assert "latency_ms" in result


@pytest.mark.django_db
def test_cache_fail(monkeypatch):
    monkeypatch.setattr(checks, "cache", FakeCache(value_to_return="wrong-value"))

    result = checks.check_cache()

    assert result == {"status": "fail", "detail": "Cache probe returned unexpected value"}


def test_celery_no_broker(monkeypatch):
    monkeypatch.delenv("CELERY_BROKER_URL", raising=False)

    result = checks.check_celery()

    assert result["status"] == "ok"
    assert "CELERY_BROKER_URL is unset" in result["detail"]


def test_celery_no_kombu(monkeypatch):
    monkeypatch.setenv("CELERY_BROKER_URL", "redis://broker")

    def raise_import_error(name):
        raise ImportError(name)

    monkeypatch.setattr(importlib, "import_module", raise_import_error)

    result = checks.check_celery()

    assert result["status"] == "ok"
    assert "kombu is not installed" in result["detail"]


def test_celery_ok(monkeypatch):
    monkeypatch.setenv("CELERY_BROKER_URL", "redis://broker")

    class FakeBrokerConnection:
        def __init__(self, url, connect_timeout):
            self.url = url
            self.connect_timeout = connect_timeout

        def __enter__(self):
            return self

        def __exit__(self, exc_type, exc, tb):
            return False

        def ensure_connection(self, max_retries):
            self.max_retries = max_retries

    monkeypatch.setattr(importlib, "import_module", lambda name: SimpleNamespace(Connection=FakeBrokerConnection))

    result = checks.check_celery()

    assert result == {"status": "ok"}


def test_celery_fail(monkeypatch):
    monkeypatch.setenv("CELERY_BROKER_URL", "redis://broker")

    class BrokenBrokerConnection:
        def __init__(self, url, connect_timeout):
            self.url = url
            self.connect_timeout = connect_timeout

        def __enter__(self):
            raise OSError("broker down")

        def __exit__(self, exc_type, exc, tb):
            return False

    monkeypatch.setattr(importlib, "import_module", lambda name: SimpleNamespace(Connection=BrokenBrokerConnection))

    result = checks.check_celery()

    assert result == {"status": "fail", "detail": "broker down"}


def test_backup_no_env(monkeypatch):
    monkeypatch.delenv("BACKUP_STATUS_FILE", raising=False)

    result = checks.check_backup()

    assert result["status"] == "fail"
    assert "BACKUP_STATUS_FILE is unset" in result["detail"]


def test_backup_missing_file(monkeypatch, tmp_path):
    status_file = tmp_path / "missing-backup-status"
    monkeypatch.setenv("BACKUP_STATUS_FILE", str(status_file))

    result = checks.check_backup()

    assert result == {"status": "fail", "detail": f"Backup status file not found: {status_file}"}


def test_backup_fresh(monkeypatch, tmp_path):
    status_file = tmp_path / "backup-status"
    status_file.write_text(str(time.time() - 60), encoding="utf-8")
    monkeypatch.setenv("BACKUP_STATUS_FILE", str(status_file))

    result = checks.check_backup()

    assert result == {"status": "ok"}


def test_backup_stale(monkeypatch, tmp_path):
    status_file = tmp_path / "backup-status"
    stale_timestamp = time.time() - (checks.BACKUP_MAX_AGE_SECONDS + 1)
    status_file.write_text(str(stale_timestamp), encoding="utf-8")
    monkeypatch.setenv("BACKUP_STATUS_FILE", str(status_file))

    result = checks.check_backup()

    assert result["status"] == "fail"
    assert "Last backup is" in result["detail"]


def test_backup_invalid(monkeypatch, tmp_path):
    status_file = tmp_path / "backup-status"
    status_file.write_text("not-a-timestamp", encoding="utf-8")
    monkeypatch.setenv("BACKUP_STATUS_FILE", str(status_file))

    result = checks.check_backup()

    assert result == {"status": "fail", "detail": "Invalid backup status file"}