"""FailoverAlerter 單元測試 — P1.5 Telegram 容災告警

四大 testcase（覆蓋 status 文件 line 99 指定範圍）：
1. test_alert_failover_dedup        — 同 to_provider 第二次被 10min dedup
2. test_alert_recovery_send         — 正常發送 + Markdown 訊息結構
3. test_no_telegram_chat_id_noop    — chat_id 缺失時不發送（fail-soft）
4. test_quota_alert_dedup_24h       — quota 告警 86400s TTL（每日一次）

2026-04-26 P1.5 補測 by Claude Opus 4.7
"""

from __future__ import annotations

from unittest.mock import AsyncMock, MagicMock, patch

import pytest

from src.services.failover_alerter import (
    DEDUP_TTL_SEC,
    QUOTA_DEDUP_TTL_SEC,
    FailoverAlerter,
    configure_alerter,
    get_failover_alerter,
    reset_failover_alerter,
)


@pytest.fixture(autouse=True)
def _reset_singleton():
    """每個 test 前後重置 singleton，避免 state 洩漏"""
    reset_failover_alerter()
    yield
    reset_failover_alerter()


@pytest.fixture
def mock_redis():
    """Mock Redis：set 第一次回 True（NX 成功），第二次回 None（已存在）"""
    redis = MagicMock()
    redis.set = AsyncMock(side_effect=[True, None, True, None])
    return redis


@pytest.fixture
def mock_telegram_send():
    """Mock TelegramGateway.send_alert_notification + settings.SRE_GROUP_CHAT_ID

    `_send()` 在函式內 inline import，必須 mock 來源 module 而非 alerter module。
    """
    with patch("src.services.telegram_gateway.get_telegram_gateway") as mock_gw, \
         patch("src.core.config.get_settings") as mock_settings:
        gateway = MagicMock()
        gateway.send_alert_notification = AsyncMock()
        mock_gw.return_value = gateway
        mock_settings.return_value = MagicMock(SRE_GROUP_CHAT_ID="-100123", OPENCLAW_TG_CHAT_ID="-100456")
        yield gateway


# =============================================================================
# Case 1: failover dedup（同 to_provider 第二次被攔）
# =============================================================================

@pytest.mark.asyncio
async def test_alert_failover_dedup(mock_redis, mock_telegram_send):
    alerter = FailoverAlerter(redis_client=mock_redis)

    event = {
        "to_provider": "gemini",
        "reason": "111 unhealthy",
        "model": "qwen3:8b",
        "fallback_chain_str": "gemini → ollama_188",
    }

    # 第 1 次：dedup pass，發送
    await alerter.alert_failover(event)
    assert mock_telegram_send.send_alert_notification.await_count == 1

    # 第 2 次：dedup hit，不發送
    await alerter.alert_failover(event)
    assert mock_telegram_send.send_alert_notification.await_count == 1  # 仍是 1

    # 驗證 dedup TTL = 10min
    assert mock_redis.set.await_args_list[0].kwargs["ex"] == DEDUP_TTL_SEC
    assert mock_redis.set.await_args_list[0].kwargs["nx"] is True


# =============================================================================
# Case 2: recovery 正常發送
# =============================================================================

@pytest.mark.asyncio
async def test_alert_recovery_send(mock_redis, mock_telegram_send):
    alerter = FailoverAlerter(redis_client=mock_redis)

    await alerter.alert_recovery({
        "from_provider": "gemini",
        "to_provider": "ollama_111",
        "stable_count": 3,
    })

    assert mock_telegram_send.send_alert_notification.await_count == 1
    sent_kwargs = mock_telegram_send.send_alert_notification.await_args.kwargs
    assert sent_kwargs["parse_mode"] == "MarkdownV2"
    # 訊息應提及恢復 + 連續 3 次 HEALTHY
    assert "Ollama 自動恢復" in sent_kwargs["text"]
    assert "連續 3" in sent_kwargs["text"]


# =============================================================================
# Case 3: chat_id 缺失 → fail-soft（不發送，不 raise）
# =============================================================================

@pytest.mark.asyncio
async def test_no_telegram_chat_id_noop(mock_redis):
    alerter = FailoverAlerter(redis_client=mock_redis)

    with patch("src.services.telegram_gateway.get_telegram_gateway") as mock_gw, \
         patch("src.core.config.get_settings") as mock_settings:
        gateway = MagicMock()
        gateway.send_alert_notification = AsyncMock()
        mock_gw.return_value = gateway
        mock_settings.return_value = MagicMock(SRE_GROUP_CHAT_ID=None, OPENCLAW_TG_CHAT_ID=None)

        # 不該 raise，dedup pass 但 send 因 chat_id 缺直接 return
        await alerter.alert_failover({"to_provider": "gemini"})
        assert gateway.send_alert_notification.await_count == 0


# =============================================================================
# Case 4: quota 告警 24h dedup
# =============================================================================

@pytest.mark.asyncio
async def test_quota_alert_dedup_24h(mock_redis, mock_telegram_send):
    alerter = FailoverAlerter(redis_client=mock_redis)

    await alerter.alert_gemini_quota_exceeded({
        "quota": 1000,
        "current_count": 1003,
    })

    # 訊息發出
    assert mock_telegram_send.send_alert_notification.await_count == 1
    sent = mock_telegram_send.send_alert_notification.await_args.kwargs["text"]
    assert "Gemini 每日配額耗盡" in sent
    assert "1000" in sent
    assert "1003" in sent
    assert "\\-" in sent  # MarkdownV2 date hyphens must be escaped

    # 驗證 dedup TTL = 24h
    assert mock_redis.set.await_args_list[0].kwargs["ex"] == QUOTA_DEDUP_TTL_SEC
    assert QUOTA_DEDUP_TTL_SEC == 86400  # sanity check 常數本身


# =============================================================================
# 額外：configure_alerter / get_failover_alerter 行為驗證
# =============================================================================

def test_configure_alerter_replaces_singleton(mock_redis):
    """configure_alerter() 應替換現有 singleton 並注入 redis"""
    a1 = get_failover_alerter()
    assert a1._redis is None  # 預設無 redis

    configure_alerter(mock_redis)
    a2 = get_failover_alerter()
    assert a2._redis is mock_redis  # 注入後 redis 可用
    assert a1 is not a2  # 是新 instance


@pytest.mark.asyncio
async def test_dedup_fail_open_when_no_redis():
    """Redis 為 None 時 dedup 第一次應允許送出（in-memory dedup，非 fail-open 對所有次數）"""
    alerter = FailoverAlerter(redis_client=None)
    # 第一次：無記錄 → 允許
    assert await alerter._check_dedup("any:key", ttl=600) is True


# =============================================================================
# Wave8-X2: dedup in-memory fallback 新增測試
# =============================================================================


@pytest.mark.asyncio
async def test_dedup_redis_unavailable_uses_memory():
    """Redis 拋出例外時，in-memory dedup 仍生效（不 fail-open 狂發）

    Wave8-X2 fix：原 fail-open 改為 in-memory dedup fallback。
    驗證：Redis set() raise → 第二次 _check_dedup 同 key 應回 False。
    """
    bad_redis = MagicMock()
    bad_redis.set = AsyncMock(side_effect=ConnectionError("Redis is down"))

    alerter = FailoverAlerter(redis_client=bad_redis)

    key = "alert:test:dedup_memory"
    ttl = 600

    # 第 1 次：in-memory 無記錄 → 允許
    result1 = await alerter._check_dedup(key, ttl=ttl)
    assert result1 is True

    # 第 2 次：in-memory 已有記錄（未過 TTL）→ 拒絕
    result2 = await alerter._check_dedup(key, ttl=ttl)
    assert result2 is False


@pytest.mark.asyncio
async def test_memory_dedup_max_size_gc():
    """超過 1000 entries 時 GC 清除過期 entry，防 dict 無限成長

    Wave8-X2 fix：_memory_dedup_max_size = 1000，超過時 GC。
    驗證：注入 999 個已過期 entry + 1 個未過期 → GC 後 dict size 應減少。
    """
    import time

    alerter = FailoverAlerter(redis_client=None)

    # 注入 999 個「已過期」entry（last_sent = 0.0，TTL=600s，均已過期）
    for i in range(999):
        alerter._memory_dedup[f"stale:key:{i}"] = 0.0  # expired: now - 0.0 > 600

    # 注入 1 個「未過期」entry
    alerter._memory_dedup["fresh:key"] = time.time()

    # 此時 dict size = 1000，達 _memory_dedup_max_size
    assert len(alerter._memory_dedup) == 1000

    # 觸發 GC：新 key check 讓 len >= max_size → 清理
    result = await alerter._check_dedup("trigger:gc:key", ttl=600)
    assert result is True  # 新 key 應被允許

    # GC 後：999 個 stale entry 被清除，只剩 fresh:key + trigger:gc:key
    assert len(alerter._memory_dedup) <= 3  # fresh + trigger + 可能有邊界差1