"""运行时配置:数据库优先,回落 .env。

后台「数据源」页可在线修改的配置项存 app_settings 表;
读取时 DB 有值用 DB,否则回落同名环境变量(pydantic settings)。
DB 读取失败时也回落环境变量,保证采集不因管理表故障而中断。
"""
from __future__ import annotations

import logging
import re
import secrets
from dataclasses import dataclass

from sqlalchemy import select
from sqlalchemy.dialects.postgresql import insert as pg_insert

from src.core import crypto
from src.core.config import settings
from src.db.base import AsyncSessionLocal
from src.db.models import AppSetting

# 管理员密码哈希在 app_settings 中的键(不进 SETTING_DEFS 白名单:
# 只能走专门的改密接口 —— 需验证当前密码,不能被通用配置接口绕过)
ADMIN_PASSWORD_HASH_KEY = "ADMIN_PASSWORD_HASH"
# .env 明文密码的键名(仅作为初始值;后台改密后以哈希为准)
_ADMIN_ENV_KEY = "ADMIN_PASSWORD"


logger = logging.getLogger(__name__)


@dataclass(frozen=True)
class SettingDef:
    key: str
    label: str
    description: str
    sensitive: bool


# 允许在后台查看/修改的配置项白名单(之外的 key 一律拒绝读写)
SETTING_DEFS: dict[str, SettingDef] = {
    "BZZOIRO_KEY": SettingDef(
        "BZZOIRO_KEY", "Bzzoiro API Key",
        "比赛赛程/比分/积分榜/统计的数据源凭证。支持多 key 轮换:用逗号、分号或换行分隔多个 key,遇到限流(429)自动切换",
        sensitive=True,
    ),
    "BZZOIRO_BASE": SettingDef(
        "BZZOIRO_BASE", "Bzzoiro API 地址", "Bzzoiro 接口基础地址", sensitive=False,
    ),
    "LLM_API_KEY": SettingDef(
        "LLM_API_KEY", "LLM API Key", "大模型服务凭证(OpenAI 兼容接口)", sensitive=True,
    ),
    "LLM_BASE_URL": SettingDef(
        "LLM_BASE_URL", "LLM 接口地址", "如 https://api.deepseek.com/v1", sensitive=False,
    ),
    "LLM_MODEL": SettingDef(
        "LLM_MODEL", "LLM 模型", "如 deepseek-chat / gpt-4o", sensitive=False,
    ),
}

# ── 按角色独立配置 LLM 的键(5 专家 + 终裁) ──
# 每个角色可独立覆盖 模型 / 接口地址 / API Key;留空继承分层默认(见 orchestrator._agent_provider)。
AGENT_META: list[dict] = [
    {"id": "form", "label": "近期状态分析专家"},
    {"id": "stats", "label": "攻防数据分析专家"},
    {"id": "home_away", "label": "主客因素分析专家"},
    {"id": "standings", "label": "联赛排名分析专家"},
    {"id": "h2h", "label": "历史交锋分析专家"},
    {"id": "aggregator", "label": "终裁分析专家"},
]

for _agent in AGENT_META:
    _u = _agent["id"].upper()
    SETTING_DEFS[f"AGENT_{_u}_MODEL"] = SettingDef(
        f"AGENT_{_u}_MODEL", f"{_agent['label']} 模型", "留空继承默认(专家层/全局)", sensitive=False,
    )
    SETTING_DEFS[f"AGENT_{_u}_BASE_URL"] = SettingDef(
        f"AGENT_{_u}_BASE_URL", f"{_agent['label']} 接口地址", "留空继承全局 LLM_BASE_URL", sensitive=False,
    )
    SETTING_DEFS[f"AGENT_{_u}_API_KEY"] = SettingDef(
        f"AGENT_{_u}_API_KEY", f"{_agent['label']} API Key", "留空继承全局 LLM_API_KEY", sensitive=True,
    )


def mask_value(value: str, sensitive: bool) -> str:
    """脱敏展示:敏感值只留末 4 位;非敏感值原样返回。

    多 key(逗号/分号/换行分隔)时显示数量,如 "3 个 key(末段 …XXXX)"。
    """
    if not value:
        return ""
    if not sensitive:
        return value
    # 检测多 key
    keys = [k.strip() for k in re.split(r"[,;\n]", value) if k.strip()]
    if len(keys) > 1:
        last = keys[-1]
        tail = last[-4:] if len(last) >= 4 else last
        return f"{len(keys)} 个 key(末段 …{tail})"
    return f"****{value[-4:]}" if len(value) >= 8 else "****"


async def get_runtime_value(key: str) -> str:
    """读运行时配置:DB 覆盖值 → .env 默认值 → 空串。

    敏感项入库时是密文,读出后自动解密;旧明文(迁移前)由 decrypt_value 透传。
    """
    defn = SETTING_DEFS.get(key)
    try:
        async with AsyncSessionLocal() as db:
            row = await db.get(AppSetting, key)
            if row and row.value:
                value = crypto.decrypt_value(row.value) if defn and defn.sensitive else row.value
                if value:
                    return value
    except Exception:
        logger.warning("读取运行时配置 %s 失败,回落环境变量", key)
    return getattr(settings, key, "") or ""


async def set_runtime_value(key: str, value: str) -> None:
    """写入/更新 DB 覆盖值(调用方需先校验 key 在白名单内)。

    敏感项(SETTING_DEFS.sensitive)以 Fernet 加密存储,库里不落明文。
    """
    defn = SETTING_DEFS.get(key)
    stored = crypto.encrypt_value(value) if defn and defn.sensitive else value
    async with AsyncSessionLocal() as db:
        stmt = pg_insert(AppSetting).values(key=key, value=stored)
        stmt = stmt.on_conflict_do_update(index_elements=["key"], set_={"value": stored})
        await db.execute(stmt)
        await db.commit()
    logger.info("运行时配置 %s 已更新", key)


async def clear_runtime_value(key: str) -> None:
    """删除 DB 覆盖值,回落 .env(调用方需先校验 key 在白名单内)。"""
    async with AsyncSessionLocal() as db:
        row = await db.get(AppSetting, key)
        if row is not None:
            await db.delete(row)
            await db.commit()
    logger.info("运行时配置 %s 已清除覆盖", key)


async def get_setting_origin(key: str) -> tuple[str, str]:
    """返回 (origin, 当前生效值)。origin ∈ db / env / none。"""
    defn = SETTING_DEFS.get(key)
    try:
        async with AsyncSessionLocal() as db:
            row = await db.get(AppSetting, key)
            if row and row.value:
                value = crypto.decrypt_value(row.value) if defn and defn.sensitive else row.value
                return "db", value
    except Exception:
        logger.warning("读取运行时配置 %s 来源失败,按环境变量处理", key)
    env_value = getattr(settings, key, "") or ""
    return ("env", env_value) if env_value else ("none", "")


async def migrate_plaintext_sensitive_settings() -> int:
    """一次性迁移:把库中仍是明文的敏感项加密(幂等,启动时执行)。

    返回加密的条数。
    """
    migrated = 0
    sensitive_keys = {k for k, d in SETTING_DEFS.items() if d.sensitive}
    async with AsyncSessionLocal() as db:
        rows = (await db.execute(select(AppSetting))).scalars().all()
        for row in rows:
            if row.key not in sensitive_keys or crypto.is_encrypted(row.value):
                continue
            row.value = crypto.encrypt_value(row.value)
            migrated += 1
        await db.commit()
    if migrated:
        logger.info("已加密迁移 %d 条明文敏感配置", migrated)
    return migrated


# ── 管理员密码:只存 scrypt 哈希,永不存明文 ──────────────────────


async def get_admin_password_hash() -> str:
    """库中管理员密码哈希;无则空串。"""
    try:
        async with AsyncSessionLocal() as db:
            row = await db.get(AppSetting, ADMIN_PASSWORD_HASH_KEY)
            return row.value if row else ""
    except Exception:
        logger.warning("读取管理员密码哈希失败")
        return ""


async def set_admin_password_hash(hash_str: str) -> None:
    async with AsyncSessionLocal() as db:
        stmt = pg_insert(AppSetting).values(key=ADMIN_PASSWORD_HASH_KEY, value=hash_str)
        stmt = stmt.on_conflict_do_update(index_elements=["key"], set_={"value": hash_str})
        await db.execute(stmt)
        await db.commit()
    logger.info("管理员密码哈希已更新")


async def verify_admin_password(candidate: str) -> bool:
    """校验管理员密码:优先哈希;哈希不存在时回落 .env 明文(未迁移的旧部署)。"""
    stored_hash = await get_admin_password_hash()
    if stored_hash:
        return crypto.verify_password(candidate, stored_hash)
    env_pw = getattr(settings, _ADMIN_ENV_KEY, "") or ""
    return bool(env_pw) and secrets.compare_digest(candidate, env_pw)


async def get_admin_credential_fingerprint() -> str:
    """管理员凭证指纹(作为会话签名密钥的输入)。

    用密码哈希而非密码本身:凭证变化 → 指纹变化 → 全部会话失效。
    """
    stored_hash = await get_admin_password_hash()
    if stored_hash:
        return f"hash:{stored_hash}"
    env_pw = getattr(settings, _ADMIN_ENV_KEY, "") or ""
    return f"env:{env_pw}" if env_pw else ""


async def _get_raw_setting(key: str) -> str:
    async with AsyncSessionLocal() as db:
        row = await db.get(AppSetting, key)
        return row.value if row else ""


async def _delete_setting(key: str) -> None:
    async with AsyncSessionLocal() as db:
        row = await db.get(AppSetting, key)
        if row is not None:
            await db.delete(row)
            await db.commit()


async def ensure_admin_password_hashed() -> bool:
    """启动迁移:确保管理员密码只以 scrypt 哈希存在(幂等)。

    迁移来源优先级:
      1. 库中旧版明文 ADMIN_PASSWORD 行(旧代码写入的当前密码,迁移后删除该明文行)
      2. .env 的 ADMIN_PASSWORD 初始值
    """
    if await get_admin_password_hash():
        # 哈希已存在:清除旧版可能残留的明文行
        if await _get_raw_setting(_ADMIN_ENV_KEY):
            await _delete_setting(_ADMIN_ENV_KEY)
            logger.info("已删除遗留的明文 ADMIN_PASSWORD 行(哈希已存在)")
        return False

    legacy_plain = await _get_raw_setting(_ADMIN_ENV_KEY)
    if legacy_plain:
        await set_admin_password_hash(crypto.hash_password(legacy_plain))
        await _delete_setting(_ADMIN_ENV_KEY)
        logger.info("已将库中明文管理员密码迁移为 scrypt 哈希,明文行已删除")
        return True

    env_pw = getattr(settings, _ADMIN_ENV_KEY, "") or ""
    if not env_pw:
        return False
    await set_admin_password_hash(crypto.hash_password(env_pw))
    logger.info(
        "已将 .env 中的明文管理员密码迁移为 scrypt 哈希。"
        "建议现在从 .env 中删除 ADMIN_PASSWORD 明文行。"
    )
    return True