"""表结构与幂等性测试（对应 development-plan.md §7.2 硬约束）。

需要真实数据库的用例标记为 ``db``；纯结构校验的用例无需数据库。
"""

from __future__ import annotations

import re

import pytest

from hdiv.core.config import load_config
from hdiv.core.errors import SafetyViolation
from hdiv.data.schema import ALL_TABLES, TABLE_NAMES

CFG = load_config("datasource")

# 需要库的表清单（无库时跳过）
_PLAIN_TESTS_NEED_DB = pytest.mark.db


# ---------------------------------------------------------------------------
# 纯结构校验（无需数据库）
# ---------------------------------------------------------------------------


def test_table_count() -> None:
    assert len(ALL_TABLES) == 30
    assert len(set(TABLE_NAMES)) == 30


def test_all_tables_use_own_prefix() -> None:
    bad = [t.name for t in ALL_TABLES if not t.name.startswith(CFG.database.own_prefix)]
    assert not bad, f"以下表未使用自有前缀：{bad}"


def test_ddl_never_contains_destructive_statements() -> None:
    destructive = re.compile(r"\b(DROP|TRUNCATE|DELETE)\b", re.IGNORECASE)
    for t in ALL_TABLES:
        assert not destructive.search(t.ddl), f"{t.name} 的 DDL 含破坏性语句"
        for m in t.migrations:
            assert not re.search(r"\b(DROP\s+TABLE|TRUNCATE|DELETE)\b", m.sql, re.IGNORECASE), (
                f"{t.name} 迁移 {m.name} 含破坏性语句：{m.sql}"
            )


def test_create_statements_are_idempotent() -> None:
    for t in ALL_TABLES:
        assert "CREATE TABLE IF NOT EXISTS" in t.ddl, f"{t.name} 未使用 IF NOT EXISTS"


def test_every_table_has_primary_key() -> None:
    for t in ALL_TABLES:
        assert "PRIMARY KEY" in t.ddl, f"{t.name} 缺少主键"


def test_tables_have_comment() -> None:
    for t in ALL_TABLES:
        assert t.comment, f"{t.name} 缺少注释"
        assert "COMMENT='" in t.ddl or 'COMMENT="' in t.ddl, f"{t.name} 的 DDL 缺少表注释"


def test_no_nullable_column_in_unique_key() -> None:
    """MySQL 唯一约束不约束 NULL —— 参与唯一键的列必须 NOT NULL。

    唯一例外是显式构造的 dedup_key（本身 NOT NULL）。
    """
    problems: list[str] = []
    for t in ALL_TABLES:
        for m in re.finditer(r"UNIQUE KEY `\w+` \(([^)]+)\)", t.ddl):
            cols = [c.strip().strip("`") for c in m.group(1).split(",")]
            for col in cols:
                # 找到该列的定义行
                pat = re.compile(rf"^\s*`{re.escape(col)}`\s+([A-Za-z]+(?:\([^)]*\))?)(.*)$", re.M)
                mm = pat.search(t.ddl)
                if not mm:
                    problems.append(f"{t.name}.{col} 未找到列定义")
                    continue
                rest = mm.group(2)
                if "NOT NULL" not in rest:
                    problems.append(
                        f"{t.name}.{col} 可空却参与唯一键 —— NULL 会绕过唯一约束造成重复"
                    )
    assert not problems, "\n".join(problems)


def test_character_set_is_utf8mb4() -> None:
    for t in ALL_TABLES:
        assert "utf8mb4" in t.ddl, f"{t.name} 未使用 utf8mb4"


def test_engine_is_innodb() -> None:
    for t in ALL_TABLES:
        assert "InnoDB" in t.ddl, f"{t.name} 未使用 InnoDB"


def test_migration_names_are_unique_within_table() -> None:
    for t in ALL_TABLES:
        names = [m.name for m in t.migrations]
        assert len(names) == len(set(names)), f"{t.name} 迁移名重复：{names}"


def test_migrations_do_not_add_dropped_tables() -> None:
    """迁移只允许 ADD/MODIFY，不允许改表名或删列。"""
    for t in ALL_TABLES:
        for m in t.migrations:
            assert not re.search(r"\bDROP\s+COLUMN\b", m.sql, re.IGNORECASE), m.sql
            assert not re.search(r"\bRENAME\b", m.sql, re.IGNORECASE), m.sql


def test_own_prefix_guard_rejects_foreign_table() -> None:
    from hdiv.data.ddl import _assert_own_prefix

    with pytest.raises(SafetyViolation):
        _assert_own_prefix(CFG, "stock")
    with pytest.raises(SafetyViolation):
        _assert_own_prefix(CFG, "hd_ok") if False else _assert_own_prefix(CFG, "alembic_version")


def test_own_prefix_guard_accepts_own_table() -> None:
    from hdiv.data.ddl import _assert_own_prefix

    _assert_own_prefix(CFG, "hd_dividend")  # 不应抛错


# ---------------------------------------------------------------------------
# 需要数据库
# ---------------------------------------------------------------------------


@_PLAIN_TESTS_NEED_DB
def test_ddl_plan_is_idempotent_on_live_db() -> None:
    """连续两次 plan 都应返回 0 个动作（结构已就绪且迁移已应用）。"""
    pytest.importorskip("pymysql")
    from hdiv.data import ddl, db

    db.load_dotenv_once()
    try:
        db.list_tables(CFG)
    except Exception as exc:  # pragma: no cover - 环境相关
        pytest.skip(f"数据库不可用：{exc}")

    actions = ddl.plan(CFG)
    assert actions == [], f"结构未收敛，仍待执行：{[(a.kind, a.table, a.detail) for a in actions]}"


@_PLAIN_TESTS_NEED_DB
def test_all_declared_tables_exist() -> None:
    pytest.importorskip("pymysql")
    from hdiv.data import db

    db.load_dotenv_once()
    try:
        existing = set(db.list_tables(CFG))
    except Exception as exc:  # pragma: no cover
        pytest.skip(f"数据库不可用：{exc}")
    missing = [t for t in TABLE_NAMES if t not in existing]
    assert not missing, f"库中缺表：{missing}"


@_PLAIN_TESTS_NEED_DB
def test_verify_reports_no_problems() -> None:
    pytest.importorskip("pymysql")
    from hdiv.data import db, ddl

    db.load_dotenv_once()
    try:
        problems = ddl.verify(CFG)
    except Exception as exc:  # pragma: no cover
        pytest.skip(f"数据库不可用：{exc}")
    assert not problems, "\n".join(problems)


@_PLAIN_TESTS_NEED_DB
def test_alembic_version_untouched() -> None:
    """决策 D1：本项目不得修改 qlib 的 Alembic 版本链。"""
    pytest.importorskip("pymysql")
    from hdiv.data import db

    db.load_dotenv_once()
    try:
        df = db.read_sql("SELECT version_num FROM alembic_version", cfg=CFG)
    except Exception as exc:  # pragma: no cover
        pytest.skip(f"数据库不可用：{exc}")
    # 只要存在且可读即可；本项目从未写入该表（由 SafetyViolation 保证）
    assert len(df) >= 1


@_PLAIN_TESTS_NEED_DB
def test_project_created_tables_all_have_own_prefix() -> None:
    """本项目建的表必须 100% 匹配 hd_ 前缀。"""
    pytest.importorskip("pymysql")
    from hdiv.data import db
    from hdiv.data.schema import TABLE_NAMES as declared

    db.load_dotenv_once()
    try:
        existing = set(db.list_tables(CFG))
    except Exception as exc:  # pragma: no cover
        pytest.skip(f"数据库不可用：{exc}")
    hd_tables = {t for t in existing if t.startswith(CFG.database.own_prefix)}
    assert hd_tables <= set(declared), f"库中存在未声明的 hd_ 表：{hd_tables - set(declared)}"
    assert set(declared) <= existing, f"声明的表未全部创建：{set(declared) - existing}"