# -*- coding: utf-8 -*-
"""④-1 PostgreSQL users 表 DDL + 映射 —— issue #150 / #30 / PRD 8.2。

定义本地账号在 PostgreSQL 中的存储结构（#30 users 表 schema），并提供
`UserStore` 与 PG 之间的映射。DDL 仅用标准库拼装（无 psycopg2 依赖），
实际接库时上层注入连接即可。

表结构（对齐 core/data-bus/postgres_schema.py 的命名风格）：

    users (
        id            BIGSERIAL PRIMARY KEY,
        username      VARCHAR(64) UNIQUE NOT NULL,
        password_hash VARCHAR(255) NOT NULL,   -- pbkdf2_sha256$<iter>$<salt>$<hash>
        role          VARCHAR(16) NOT NULL DEFAULT 'readonly',  -- readonly/engineer/admin
        active        BOOLEAN NOT NULL DEFAULT TRUE,
        created_at    TIMESTAMPTZ NOT NULL DEFAULT now(),
        last_login_at TIMESTAMPTZ
    )

索引：username 唯一索引（登录走 username）；role 普通索引（用户管理筛选）。
"""
from __future__ import annotations

from typing import Any, Dict, List

from .users import User, VALID_ROLES

USERS_TABLE_DDL = """CREATE TABLE IF NOT EXISTS users (
    id            BIGSERIAL PRIMARY KEY,
    username      VARCHAR(64) UNIQUE NOT NULL,
    password_hash VARCHAR(255) NOT NULL,
    role          VARCHAR(16) NOT NULL DEFAULT 'readonly',
    active        BOOLEAN     NOT NULL DEFAULT TRUE,
    created_at    TIMESTAMPTZ NOT NULL DEFAULT now(),
    last_login_at TIMESTAMPTZ,
    CONSTRAINT users_role_chk CHECK (role IN ('readonly','engineer','admin'))
);
CREATE INDEX IF NOT EXISTS idx_users_role ON users(role);
"""


def row_to_user(row: Any) -> User:
    """PG 行（dict/tuple-like）→ User。row 需含 keys: id/username/password_hash/role/active/created_at/last_login_at。"""
    def g(k, default=None):
        if isinstance(row, dict):
            return row.get(k, default)
        return getattr(row, k, default)
    created = g("created_at")
    last = g("last_login_at")
    # PG TIMESTAMPTZ → epoch（若为 datetime 有 timestamp()）
    def to_epoch(v):
        if v is None:
            return None
        if hasattr(v, "timestamp"):
            return v.timestamp()
        return v
    return User(
        id=int(g("id")),
        username=str(g("username")),
        password_hash=str(g("password_hash")),
        role=str(g("role", "readonly")) or "readonly",
        active=bool(g("active", True)),
        created_at=to_epoch(created) or 0.0,
        last_login_at=to_epoch(last),
    )


def user_to_row(user: User) -> Dict[str, Any]:
    """User → PG 列字典（不含 id，用于 INSERT；UPDATE 时按 id 定位）。"""
    return {
        "username": user.username,
        "password_hash": user.password_hash,
        "role": user.role,
        "active": user.active,
    }


def validate_role(role: str) -> str:
    if role not in VALID_ROLES:
        raise ValueError("role must be one of %r" % (VALID_ROLES,))
    return role


__all__ = ["USERS_TABLE_DDL", "row_to_user", "user_to_row", "validate_role"]