"""RedisTaskStore unit tests - uses mock Redis (no real Redis required)"""

import json
from datetime import datetime, timezone
from unittest.mock import AsyncMock, MagicMock, patch

import pytest

from agentkit.core.protocol import TaskStatus
from agentkit.server.task_store import (
    InMemoryTaskStore,
    RedisTaskStore,
    TaskRecord,
    TaskStore,
    create_task_store,
)


# ═══════════════════════════════════════════════════════════
# Helpers – lightweight fake Redis for unit tests
# ═══════════════════════════════════════════════════════════


class FakeRedis:
    """Minimal in-memory fake that satisfies the RedisTaskStore interface."""

    def __init__(self):
        self._data: dict[str, str] = {}

    @classmethod
    def from_url(cls, url, **kwargs):
        return cls()

    async def get(self, key):
        return self._data.get(key)

    async def set(self, key, value, ex=None, **kwargs):
        self._data[key] = value

    async def delete(self, key):
        self._data.pop(key, None)

    async def mget(self, keys):
        return [self._data.get(k) for k in keys]

    async def scan(self, cursor=0, match=None, count=200):
        """Simplified SCAN – returns all matching keys in one batch."""
        import fnmatch

        pattern = match or "*"
        matched = [k for k in self._data if fnmatch.fnmatch(k, pattern)]
        # cursor=0 means "done"
        return (0, matched)

    async def close(self):
        pass

    async def eval(self, script, numkeys, *args):
        """Simulate Redis EVAL for the update_status Lua script."""
        # This implements the same logic as _UPDATE_STATUS_SCRIPT in RedisTaskStore
        key = args[0]
        ttl = int(args[1])
        n = int(args[2])
        raw = self._data.get(key)
        if raw is None:
            return None
        data = json.loads(raw)
        for i in range(n):
            k = args[3 + 2 * i]
            v = args[4 + 2 * i]
            # Try to parse JSON values (dicts/lists), otherwise keep as string
            try:
                data[k] = json.loads(v)
            except (json.JSONDecodeError, TypeError):
                data[k] = v
        encoded = json.dumps(data)
        self._data[key] = encoded
        return encoded


def _make_redis_store(fake_redis: FakeRedis | None = None) -> RedisTaskStore:
    """Build a RedisTaskStore with a FakeRedis injected."""
    store = RedisTaskStore(redis_url="redis://fake/0")
    if fake_redis is None:
        fake_redis = FakeRedis()
    store._redis = fake_redis
    return store


# ═══════════════════════════════════════════════════════════
# TaskRecord.from_dict round-trip
# ═══════════════════════════════════════════════════════════


class TestTaskRecordRoundTrip:
    """Verify TaskRecord serialisation / deserialisation."""

    def test_to_dict_from_dict_round_trip(self):
        now = datetime.now(timezone.utc)
        record = TaskRecord(
            task_id="t1",
            agent_name="agent_a",
            skill_name="skill_x",
            input_data={"query": "hello"},
            status=TaskStatus.RUNNING,
            output_data={"result": "world"},
            error_message=None,
            created_at=now,
            started_at=now,
            completed_at=None,
            progress=0.5,
            progress_message="Halfway",
            metadata={"key": "val"},
        )
        restored = TaskRecord.from_dict(record.to_dict())
        assert restored.task_id == record.task_id
        assert restored.agent_name == record.agent_name
        assert restored.skill_name == record.skill_name
        assert restored.input_data == record.input_data
        assert restored.status == record.status
        assert restored.output_data == record.output_data
        assert restored.progress == record.progress
        assert restored.progress_message == record.progress_message
        assert restored.metadata == record.metadata

    def test_from_dict_with_none_fields(self):
        data = {
            "task_id": "t2",
            "agent_name": "b",
            "skill_name": None,
            "input_data": {},
            "status": "pending",
            "output_data": None,
            "error_message": None,
            "created_at": datetime.now(timezone.utc).isoformat(),
            "started_at": None,
            "completed_at": None,
            "progress": 0.0,
            "progress_message": "",
            "metadata": {},
        }
        record = TaskRecord.from_dict(data)
        assert record.skill_name is None
        assert record.started_at is None
        assert record.completed_at is None


# ═══════════════════════════════════════════════════════════
# RedisTaskStore – happy path
# ═══════════════════════════════════════════════════════════


class TestRedisTaskStoreHappyPath:
    """Core CRUD operations on RedisTaskStore with mock Redis."""

    @pytest.mark.asyncio
    async def test_create_and_get(self):
        store = _make_redis_store()
        record = await store.create("t1", "agent_a", {"q": "hello"}, skill_name="skill_x")
        assert record.task_id == "t1"
        assert record.agent_name == "agent_a"
        assert record.skill_name == "skill_x"
        assert record.input_data == {"q": "hello"}
        assert record.status == TaskStatus.PENDING

        fetched = await store.get("t1")
        assert fetched is not None
        assert fetched.task_id == "t1"
        assert fetched.agent_name == "agent_a"

    @pytest.mark.asyncio
    async def test_update_status_changes_fields(self):
        store = _make_redis_store()
        await store.create("t1", "agent_a", {})
        now = datetime.now(timezone.utc)
        updated = await store.update_status(
            "t1", TaskStatus.RUNNING, started_at=now, progress=0.5, progress_message="Halfway",
        )
        assert updated.status == TaskStatus.RUNNING
        assert updated.progress == 0.5
        assert updated.progress_message == "Halfway"

        # Verify persistence
        fetched = await store.get("t1")
        assert fetched is not None
        assert fetched.status == TaskStatus.RUNNING
        assert fetched.progress == 0.5

    @pytest.mark.asyncio
    async def test_list_tasks_sorted_by_created_at_desc(self):
        store = _make_redis_store()
        await store.create("t1", "agent_a", {})
        await store.create("t2", "agent_b", {})
        tasks = await store.list_tasks()
        assert len(tasks) == 2
        # Most recent first (t2 created after t1)
        assert tasks[0].task_id == "t2"
        assert tasks[1].task_id == "t1"

    @pytest.mark.asyncio
    async def test_list_tasks_filtered_by_status(self):
        store = _make_redis_store()
        await store.create("t1", "agent_a", {})
        await store.create("t2", "agent_b", {})
        await store.update_status("t1", TaskStatus.COMPLETED, completed_at=datetime.now(timezone.utc))
        tasks = await store.list_tasks(status=TaskStatus.COMPLETED)
        assert len(tasks) == 1
        assert tasks[0].task_id == "t1"

    @pytest.mark.asyncio
    async def test_list_tasks_respects_limit(self):
        store = _make_redis_store()
        for i in range(5):
            await store.create(f"t{i}", "agent_a", {})
        tasks = await store.list_tasks(limit=3)
        assert len(tasks) == 3

    @pytest.mark.asyncio
    async def test_size_returns_count(self):
        store = _make_redis_store()
        assert await store.size == 0
        await store.create("t1", "agent_a", {})
        assert await store.size == 1
        await store.create("t2", "agent_b", {})
        assert await store.size == 2

    @pytest.mark.asyncio
    async def test_start_cleanup_is_noop(self):
        store = _make_redis_store()
        # Should not raise
        await store.start_cleanup()

    @pytest.mark.asyncio
    async def test_stop_cleanup_closes_redis(self):
        fake = FakeRedis()
        store = _make_redis_store(fake)
        await store.stop_cleanup()
        assert store._redis is None


# ═══════════════════════════════════════════════════════════
# RedisTaskStore – error / edge cases
# ═══════════════════════════════════════════════════════════


class TestRedisTaskStoreErrors:
    """Error and edge-case handling."""

    @pytest.mark.asyncio
    async def test_get_nonexistent_returns_none(self):
        store = _make_redis_store()
        result = await store.get("nonexistent")
        assert result is None

    @pytest.mark.asyncio
    async def test_update_status_nonexistent_raises_keyerror(self):
        store = _make_redis_store()
        with pytest.raises(KeyError, match="not found"):
            await store.update_status("nonexistent", TaskStatus.RUNNING)

    @pytest.mark.asyncio
    async def test_max_records_evicts_oldest_completed(self):
        fake = FakeRedis()
        store = _make_redis_store(fake)
        store._max_records = 2

        await store.create("t1", "agent_a", {})
        await store.update_status("t1", TaskStatus.COMPLETED, completed_at=datetime.now(timezone.utc))
        await store.create("t2", "agent_b", {})
        # t3 should evict t1 (oldest completed)
        await store.create("t3", "agent_c", {})
        assert await store.get("t1") is None
        assert await store.get("t2") is not None
        assert await store.get("t3") is not None

    @pytest.mark.asyncio
    async def test_max_records_full_no_completed_raises(self):
        fake = FakeRedis()
        store = _make_redis_store(fake)
        store._max_records = 1

        await store.create("t1", "agent_a", {})
        # All tasks are PENDING, no completed to evict
        with pytest.raises(RuntimeError, match="full"):
            await store.create("t2", "agent_b", {})


# ═══════════════════════════════════════════════════════════
# TTL expiry (simulated by removing key from fake Redis)
# ═══════════════════════════════════════════════════════════


class TestRedisTaskStoreTTL:
    """Simulate TTL expiry by manually removing keys from FakeRedis."""

    @pytest.mark.asyncio
    async def test_expired_key_returns_none(self):
        fake = FakeRedis()
        store = _make_redis_store(fake)
        await store.create("t1", "agent_a", {})
        # Simulate TTL expiry: remove key from fake Redis
        fake._data.pop(store._key("t1"))
        result = await store.get("t1")
        assert result is None


# ═══════════════════════════════════════════════════════════
# create_task_store factory
# ═══════════════════════════════════════════════════════════


class TestCreateTaskStore:
    """Factory function tests."""

    def test_default_backend_is_memory(self):
        store = create_task_store()
        assert isinstance(store, InMemoryTaskStore)

    def test_explicit_memory_backend(self):
        store = create_task_store(backend="memory")
        assert isinstance(store, InMemoryTaskStore)

    def test_redis_backend_returns_redis_task_store(self):
        store = create_task_store(backend="redis", redis_url="redis://localhost:6379/0")
        assert isinstance(store, RedisTaskStore)

    def test_redis_unavailable_falls_back_to_memory(self):
        """If redis.asyncio import fails, factory falls back to InMemoryTaskStore."""
        with patch.dict("sys.modules", {"redis.asyncio": None}):
            # Force import failure
            with patch("builtins.__import__", side_effect=ImportError("no redis")):
                store = create_task_store(backend="redis")
                assert isinstance(store, InMemoryTaskStore)

    def test_backward_compat_alias(self):
        """TaskStore is an alias for InMemoryTaskStore."""
        assert TaskStore is InMemoryTaskStore