"""SQLite 数据库连接与初始化（分库）

- assets.db ：Provider / Asset / VPSDetail / DomainDetail / AIAccount / Account
- metrics.db：MetricPoint / ServerInfo / SecurityCheck / EventLog
"""

import logging
from pathlib import Path
from typing import Generator

from sqlmodel import Session, SQLModel, create_engine

logger = logging.getLogger("vps-manager.db")

BASE_DIR = Path(__file__).resolve().parent.parent
DATA_DIR = BASE_DIR / "data"
DATA_DIR.mkdir(parents=True, exist_ok=True)

ASSETS_DB_URL = f"sqlite:///{DATA_DIR / 'assets.db'}"
METRICS_DB_URL = f"sqlite:///{DATA_DIR / 'metrics.db'}"

# timeout：sqlite3 内置 busy 等待（秒），随连接创建生效。
# SQLite 默认使用 NullPool（每请求新建连接），PRAGMA busy_timeout 只在单连接有效，
# 必须通过 connect_args 传递，否则并发写入（Agent 上报 + 清理任务）会报 database is locked。
assets_engine = create_engine(
    ASSETS_DB_URL,
    echo=False,
    connect_args={"check_same_thread": False, "timeout": 30},
)
metrics_engine = create_engine(
    METRICS_DB_URL,
    echo=False,
    connect_args={"check_same_thread": False, "timeout": 30},
)


def _enable_wal(engine) -> None:
    """启用 WAL 模式，提升 SQLite 并发读写能力（journal_mode 持久化到库文件，设置一次即可）"""
    import sqlalchemy as sa
    with engine.connect() as conn:
        conn.execute(sa.text("PRAGMA journal_mode=WAL"))


_enable_wal(assets_engine)
_enable_wal(metrics_engine)

# 兼容旧代码：默认 engine 指向资产库
engine = assets_engine


def init_db() -> None:
    """分库建表（幂等，可重复调用）"""
    from app.models.asset import Account, AIAccount, Asset, CloudflareDetail, DomainDetail, VPSDetail  # noqa: F401
    from app.models.credential import Credential  # noqa: F401
    from app.models.monitor import (  # noqa: F401
        EventLog,
        MetricPoint,
        SecurityCheck,
        ServerInfo,
    )
    from app.models.provider import Provider  # noqa: F401
    from app.models.ssl import SiteCert, Subdomain  # noqa: F401

    asset_models = [Provider, Asset, VPSDetail, DomainDetail, AIAccount, CloudflareDetail, Subdomain, SiteCert, Credential, Account]
    metric_models = [MetricPoint, ServerInfo, SecurityCheck, EventLog]

    SQLModel.metadata.create_all(
        assets_engine, tables=[m.__table__ for m in asset_models]
    )
    SQLModel.metadata.create_all(
        metrics_engine, tables=[m.__table__ for m in metric_models]
    )
    _migrate_assets_db()
    _migrate_indexes()


def _migrate_assets_db() -> None:
    """轻量迁移：为已有表补充新增列（SQLite create_all 不会修改已有表结构）"""
    import sqlalchemy as sa

    with assets_engine.begin() as conn:
        insp = sa.inspect(conn)
        if insp.has_table("assets"):
            cols = {c["name"] for c in insp.get_columns("assets")}
            if "external_id" not in cols:
                conn.execute(sa.text("ALTER TABLE assets ADD COLUMN external_id VARCHAR"))
            if "renew_url" not in cols:
                conn.execute(sa.text("ALTER TABLE assets ADD COLUMN renew_url VARCHAR"))
            if "cancel_url" not in cols:
                conn.execute(sa.text("ALTER TABLE assets ADD COLUMN cancel_url VARCHAR"))
            if "account_id" not in cols:
                conn.execute(sa.text("ALTER TABLE assets ADD COLUMN account_id INTEGER"))
            # 资产账号引用从 name 字符串迁移到 account_id 外键（幂等）
            _backfill_asset_account_id(conn)
        if insp.has_table("providers"):
            cols = {c["name"] for c in insp.get_columns("providers")}
            if "last_synced_at" not in cols:
                conn.execute(sa.text("ALTER TABLE providers ADD COLUMN last_synced_at DATETIME"))
            if "services" not in cols:
                conn.execute(sa.text("ALTER TABLE providers ADD COLUMN services VARCHAR DEFAULT ''"))
            # 预设平台的 sdk_type / services 对齐当前代码能力（幂等，用户自建行不动）
            _align_preset_providers(conn)
        if insp.has_table("ai_accounts"):
            cols = {c["name"] for c in insp.get_columns("ai_accounts")}
            if "api_key_encrypted" not in cols:
                conn.execute(sa.text("ALTER TABLE ai_accounts ADD COLUMN api_key_encrypted VARCHAR"))
            # 迁移：将明文 api_key 加密后存入 api_key_encrypted，并清空原字段
            _migrate_plaintext_api_keys(conn)
        if insp.has_table("accounts"):
            cols = {c["name"] for c in insp.get_columns("accounts")}
            if "login_user" not in cols:
                conn.execute(sa.text("ALTER TABLE accounts ADD COLUMN login_user VARCHAR"))
            if "login_password_encrypted" not in cols:
                conn.execute(sa.text("ALTER TABLE accounts ADD COLUMN login_password_encrypted VARCHAR"))
            if "api_config_encrypted" not in cols:
                conn.execute(sa.text("ALTER TABLE accounts ADD COLUMN api_config_encrypted VARCHAR"))
            if "last_synced_at" not in cols:
                conn.execute(sa.text("ALTER TABLE accounts ADD COLUMN last_synced_at DATETIME"))
            if "credential_id" not in cols:
                conn.execute(sa.text("ALTER TABLE accounts ADD COLUMN credential_id INTEGER"))
            # 凭证下沉：平台 api_config 迁到默认账号；AI 资产自动挂靠账号
            _backfill_account_credentials(conn)
            # 合并存量 (platform,name) 重复账号，为建唯一索引做准备
            _dedupe_accounts(conn)
            # 凭据中心化：账号登录密码搬入 credentials（唯一事实源）
            _migrate_account_credentials_to_vault(conn)
        if insp.has_table("credentials"):
            cols = {c["name"] for c in insp.get_columns("credentials")}
            if "otp_verified_at" not in cols:
                conn.execute(
                    sa.text("ALTER TABLE credentials ADD COLUMN otp_verified_at DATETIME")
                )
                # 旧版绑定强制校验过动态码，回填为「已验证」，避免升级后全量误报
                conn.execute(
                    sa.text(
                        "UPDATE credentials SET otp_verified_at = COALESCE(updated_at, created_at) "
                        "WHERE otp_secret_encrypted IS NOT NULL AND otp_secret_encrypted != ''"
                    )
                )


def _migrate_indexes() -> None:
    """为已有数据库补充复合索引（create_all 不会为已存在的表补索引，IF NOT EXISTS 幂等）"""
    import sqlalchemy as sa

    # 旧的全局 name 唯一索引（早期 Account.name unique=True 产物）会阻止跨平台同名，
    # 与新的 (platform,name) 联合唯一冲突，需先删除
    with assets_engine.begin() as conn:
        conn.execute(sa.text("DROP INDEX IF EXISTS ix_accounts_name"))

    stmts = [
        (assets_engine, "CREATE INDEX IF NOT EXISTS ix_assets_provider_ext_type ON assets (provider_id, external_id, asset_type)"),
        (assets_engine, "CREATE INDEX IF NOT EXISTS ix_assets_account_id ON assets (account_id)"),
        # (platform, name) 联合唯一：同邮箱可跨平台复用，同平台内不重名
        (assets_engine, "CREATE UNIQUE INDEX IF NOT EXISTS uq_accounts_platform_name ON accounts (platform, name)"),
        # 已有 accounts 表不会因模型加 index=True 自动补索引，显式创建
        (assets_engine, "CREATE INDEX IF NOT EXISTS ix_accounts_credential_id ON accounts (credential_id)"),
        (metrics_engine, "CREATE INDEX IF NOT EXISTS ix_metric_points_asset_ts ON metric_points (asset_id, ts)"),
        (metrics_engine, "CREATE INDEX IF NOT EXISTS ix_security_checks_asset_ts ON security_checks (asset_id, ts)"),
    ]
    for eng, sql in stmts:
        with eng.begin() as conn:
            conn.execute(sa.text(sql))


def _migrate_plaintext_api_keys(conn) -> None:
    """一次性迁移：将 ai_accounts 中残留的明文 api_key 加密后存入 api_key_encrypted，并清空原字段"""
    import sqlalchemy as sa
    from app.core.crypto import encrypt

    rows = conn.execute(
        sa.text("SELECT id, api_key FROM ai_accounts WHERE api_key IS NOT NULL AND api_key != ''")
    ).fetchall()
    if not rows:
        return
    for row in rows:
        encrypted = encrypt(row[1])
        if encrypted:
            conn.execute(
                sa.text("UPDATE ai_accounts SET api_key_encrypted = :enc, api_key = NULL WHERE id = :id"),
                {"enc": encrypted, "id": row[0]},
            )


def _align_preset_providers(conn) -> None:
    """把预设平台的 sdk_type / services 对齐到当前代码能力（幂等）

    seed_providers 只插入缺失 slug、不更新已有行，所以代码侧的能力变化
    （新增适配器、废弃从未实现的 sdk_type）必须在这里落地，否则线上会长期
    停留在旧声明上。

    - sdk_type：库里声明的值不在适配器注册表内就清空。留着会让平台卡片显示
      「API 对接: xxx」，用户建好账号点同步才撞「暂不支持的 SDK 类型」——
      声明支持却不支持，比明说不支持更糟。
    - services：只增量补标签，不删除。用户可能手动加过标签（线上 aliyun-intl
      就多了 ai_agent/other），按种子值整体覆盖会丢用户配置。

    只处理 slug 命中 PRESET_PROVIDERS 的行，用户自建平台（如 tothost）不动。
    """
    import sqlalchemy as sa
    from app.adapters import registry
    from app.core.seed import PRESET_PROVIDERS

    supported = set(registry.supported_types())
    preset = {d["slug"]: d for d in PRESET_PROVIDERS}

    rows = conn.execute(
        sa.text("SELECT id, slug, sdk_type, services FROM providers")
    ).fetchall()

    for row in rows:
        data = preset.get(row[1])
        if not data:
            continue

        declared = row[2]
        if declared and declared not in supported:
            conn.execute(
                sa.text("UPDATE providers SET sdk_type = NULL WHERE id = :id"),
                {"id": row[0]},
            )

        seed_services = [s.strip() for s in (data.get("services") or "").split(",") if s.strip()]
        if not seed_services:
            continue
        current = [s.strip() for s in (row[3] or "").split(",") if s.strip()]
        missing = [s for s in seed_services if s not in current]
        if missing:
            conn.execute(
                sa.text("UPDATE providers SET services = :services WHERE id = :id"),
                {"services": ",".join(current + missing), "id": row[0]},
            )


def _dedupe_accounts(conn) -> None:
    """建 (platform,name) 唯一索引前的防护：合并存量重复账号。

    platform 统一按 COALESCE(platform,'') 规范化比较（避免 NULL 绕过）。
    重复时保留 id 最小者，将其余行的资产引用(account_id/account)与凭证并入后删除。
    当前数据量小，预期无重复；此函数仅在发现重复时产生写操作。
    """
    import sqlalchemy as sa

    rows = conn.execute(
        sa.text(
            "SELECT COALESCE(platform,'') AS p, name, COUNT(*) AS c, MIN(id) AS keep_id "
            "FROM accounts GROUP BY p, name HAVING c > 1"
        )
    ).fetchall()
    for p, name, _c, keep_id in rows:
        dups = conn.execute(
            sa.text(
                "SELECT id FROM accounts WHERE COALESCE(platform,'') = :p AND name = :n AND id != :keep"
            ),
            {"p": p, "n": name, "keep": keep_id},
        ).fetchall()
        for (dup_id,) in dups:
            # 资产引用并入保留行
            conn.execute(
                sa.text("UPDATE assets SET account_id = :keep WHERE account_id = :dup"),
                {"keep": keep_id, "dup": dup_id},
            )
            # 凭证：保留行为空时才从重复行拷贝
            conn.execute(
                sa.text(
                    "UPDATE accounts SET "
                    "api_config_encrypted = COALESCE(api_config_encrypted, (SELECT api_config_encrypted FROM accounts WHERE id = :dup)), "
                    "login_password_encrypted = COALESCE(login_password_encrypted, (SELECT login_password_encrypted FROM accounts WHERE id = :dup)), "
                    "login_user = COALESCE(login_user, (SELECT login_user FROM accounts WHERE id = :dup)) "
                    "WHERE id = :keep"
                ),
                {"keep": keep_id, "dup": dup_id},
            )
            conn.execute(sa.text("DELETE FROM accounts WHERE id = :dup"), {"dup": dup_id})


def _migrate_account_credentials_to_vault(conn) -> None:
    """凭据中心化迁移（幂等）：把账号登录密码搬入 credentials 表。

    规则（spec §5）：
    - 仅迁移 login_password_encrypted 非空且 credential_id 为空的账号（重跑不重复建）
    - site = providers.name（platform=slug 匹配）→ 否则 platform 原文 → 否则 '未分类'
    - username = COALESCE(login_user, name)
    - login_type 写入 enum 成员名 'PASSWORD'（SQLAlchemy Enum 列存名不存值，
      与现有 assets.asset_type='VPS' 等形态一致）
    - 密文原样搬入（不解密再加密，避免中间态明文暴露）
    - 搬入成功后置空 accounts.login_password_encrypted（唯一事实源，防双份漂移）
    """
    import sqlalchemy as sa
    from datetime import datetime, timezone

    rows = conn.execute(
        sa.text(
            "SELECT a.id, a.name, a.login_user, a.login_password_encrypted, "
            "COALESCE(a.platform, ''), COALESCE(p.name, '') "
            "FROM accounts a LEFT JOIN providers p ON p.slug = COALESCE(a.platform, '') "
            "WHERE a.login_password_encrypted IS NOT NULL AND a.login_password_encrypted != '' "
            "AND a.credential_id IS NULL"
        )
    ).fetchall()
    for acc_id, name, login_user, pwd_enc, platform, provider_name in rows:
        site = provider_name or platform or "未分类"
        username = login_user or name
        now = datetime.now(timezone.utc).replace(tzinfo=None)
        conn.execute(
            sa.text(
                "INSERT INTO credentials (site, username, login_type, password_encrypted, "
                "created_at, updated_at) VALUES (:site, :username, 'PASSWORD', :pwd, :now, :now)"
            ),
            {"site": site, "username": username, "pwd": pwd_enc, "now": now},
        )
        cred_id = conn.execute(sa.text("SELECT last_insert_rowid()")).scalar()
        conn.execute(
            sa.text(
                "UPDATE accounts SET credential_id = :cid, login_password_encrypted = NULL "
                "WHERE id = :id"
            ),
            {"cid": cred_id, "id": acc_id},
        )


def _backfill_asset_account_id(conn) -> None:
    """资产账号引用迁移（幂等）：把 Asset.account 的 name 字符串引用回填为 account_id 外键。

    匹配规则：按 accounts.name 匹配；同名多个时优先 platform 与 asset.provider 一致者。
    匹配不到（历史自由文本/未登记账号）则跳过并保留 account 字符串，供人工处理。
    """
    import sqlalchemy as sa

    rows = conn.execute(
        sa.text(
            "SELECT id, account, provider FROM assets "
            "WHERE account_id IS NULL AND account IS NOT NULL AND account != ''"
        )
    ).fetchall()
    if not rows:
        return
    for asset_id, acc_name, provider in rows:
        # 同名账号可能多个：优先 platform 与资产 provider 一致的
        cand = conn.execute(
            sa.text(
                "SELECT id, COALESCE(platform,'') FROM accounts WHERE name = :n "
                "ORDER BY (COALESCE(platform,'') = :prov) DESC, id ASC"
            ),
            {"n": acc_name, "prov": provider or ""},
        ).fetchall()
        if cand:
            conn.execute(
                sa.text("UPDATE assets SET account_id = :aid WHERE id = :id"),
                {"aid": cand[0][0], "id": asset_id},
            )


def _backfill_account_credentials(conn) -> None:
    """凭证下沉迁移（幂等，仅在首次加列后产生效果）：

    1. 平台凭证下沉：api_config_encrypted 非空的 Provider → 确保存在
       「{slug}-默认」账号并拷入凭证（不删平台原值，保留可回滚）。
    2. AI 资产挂靠：account 为空的 ai_agent 资产 → 按 ai_accounts.provider
       找/建账号并关联；账号无 API 配置时把该资产的 api_key 写入账号配置。
    """
    import json
    from datetime import datetime, timezone

    import sqlalchemy as sa

    from app.core.crypto import decrypt, encrypt

    def _ensure_account(name: str, platform: str) -> int:
        # 按 (platform, name) 查，避免同名跨平台账号混淆
        row = conn.execute(
            sa.text("SELECT id FROM accounts WHERE name = :name AND COALESCE(platform,'') = :platform"),
            {"name": name, "platform": platform},
        ).first()
        if row:
            return row[0]
        conn.execute(
            sa.text("INSERT INTO accounts (name, platform, created_at) VALUES (:name, :platform, :ts)"),
            {"name": name, "platform": platform, "ts": datetime.now(timezone.utc).replace(tzinfo=None)},
        )
        return conn.execute(
            sa.text("SELECT id FROM accounts WHERE name = :name AND COALESCE(platform,'') = :platform"),
            {"name": name, "platform": platform},
        ).first()[0]

    # 1. 平台凭证下沉到默认账号
    for pid, slug, cfg in conn.execute(
        sa.text(
            "SELECT id, slug, api_config_encrypted FROM providers "
            "WHERE api_config_encrypted IS NOT NULL AND api_config_encrypted != ''"
        )
    ).fetchall():
        acc_name = f"{slug}-默认"
        _ensure_account(acc_name, slug)
        conn.execute(
            sa.text(
                "UPDATE accounts SET api_config_encrypted = :cfg "
                "WHERE name = :name AND COALESCE(platform,'') = :platform "
                "AND (api_config_encrypted IS NULL OR api_config_encrypted = '')"
            ),
            {"cfg": cfg, "name": acc_name, "platform": slug},
        )

    # 2. 无账号的 AI 资产按 provider 挂靠（account_id 外键 + account 字符串兼容）
    #    注意：SQLAlchemy Enum 列存的是成员名（'AI_AGENT'）而不是枚举值（'ai_agent'），
    #    写值会让这个分支静默零命中（同文件 _migrate_account_credentials_to_vault 用的 'PASSWORD' 即成员名）
    rows = conn.execute(
        sa.text(
            "SELECT a.id, COALESCE(ai.provider, '') FROM assets a "
            "JOIN ai_accounts ai ON ai.asset_id = a.id "
            "WHERE a.asset_type = 'AI_AGENT' AND a.account_id IS NULL AND (a.account IS NULL OR a.account = '')"
        )
    ).fetchall()
    attached = 0
    for asset_id, provider in rows:
        if not provider:
            continue
        # 沿用步骤 1 的「{slug}-默认」命名：同平台已有账号时直接复用。
        # 用裸 provider 名会建出「deepseek」与「deepseek-默认」两个语义重复的账号，
        # 而新建那个没凭证，在 UI 上点同步/测试会直接报「缺少凭证配置」
        acc_id = _ensure_account(f"{provider}-默认", provider)
        conn.execute(
            sa.text("UPDATE assets SET account = :acc, account_id = :aid WHERE id = :id"),
            {"acc": provider, "aid": acc_id, "id": asset_id},
        )
        attached += 1
        # 账号尚无 API 配置时，把该资产的 api_key 写入账号配置（解密后重组 JSON 再加密）
        key_row = conn.execute(
            sa.text("SELECT api_key_encrypted FROM ai_accounts WHERE asset_id = :id"),
            {"id": asset_id},
        ).first()
        if key_row and key_row[0]:
            api_key = decrypt(key_row[0])
            if api_key:
                cfg_json = json.dumps({"api_key": api_key})
                cfg_enc = encrypt(cfg_json)
                if cfg_enc:
                    conn.execute(
                        sa.text(
                            "UPDATE accounts SET api_config_encrypted = :cfg "
                            "WHERE id = :aid "
                            "AND (api_config_encrypted IS NULL OR api_config_encrypted = '')"
                        ),
                        {"cfg": cfg_enc, "aid": acc_id},
                    )
    if attached:
        # 这段迁移每次启动都会重跑（幂等），有实际改动时必须留痕迹便于事后核对
        logger.info("凭证下沉迁移：本次将 %s 个 AI 资产挂靠到账号", attached)


def get_session() -> Generator[Session, None, None]:
    """资产库会话（默认）

    expire_on_commit=False：commit 后不失效对象属性，避免后续访问触发隐式
    重新加载查询；需要最新值的场景由调用方显式 session.refresh()。
    """
    with Session(assets_engine, expire_on_commit=False) as session:
        yield session


def get_metrics_session() -> Generator[Session, None, None]:
    """监控 / 日志库会话"""
    with Session(metrics_engine, expire_on_commit=False) as session:
        yield session