"""Fail-closed production security checks without exposing secret values."""
from __future__ import annotations

from typing import Any
from urllib.parse import unquote, urlsplit

from app.config import Settings, settings


_PLACEHOLDER_MARKERS = (
    "change-me",
    "change-this",
    "password",
    "dev-key",
    "example",
)
_LOOPBACK_HOSTS = {"127.0.0.1", "localhost", "::1"}


def _finding(code: str, severity: str, message: str) -> dict[str, str]:
    return {"code": code, "severity": severity, "message": message}


def _looks_insecure_secret(value: str, *, minimum: int = 32) -> bool:
    normalized = value.strip().lower()
    return (
        len(value.strip()) < minimum
        or any(marker in normalized for marker in _PLACEHOLDER_MARKERS)
    )


def _url_password(value: str) -> str:
    try:
        parsed = urlsplit(value)
        return unquote(parsed.password or "")
    except ValueError:
        return ""


def _csv_values(value: str) -> list[str]:
    return [item.strip() for item in value.split(",") if item.strip()]


def security_readiness(config: Settings = settings) -> dict[str, Any]:
    """Return a sanitized security report suitable for an admin endpoint."""

    production = config.app_environment.strip().lower() in {
        "production",
        "prod",
        "server",
    }
    findings: list[dict[str, str]] = []

    if _looks_insecure_secret(config.auth_secret):
        findings.append(
            _finding("AUTH_SECRET", "critical", "JWT 签名密钥未替换或强度不足")
        )
    if _looks_insecure_secret(config.interface_api_secret):
        findings.append(
            _finding(
                "INTERFACE_API_SECRET",
                "critical",
                "接口密钥散列密钥未独立配置或强度不足",
            )
        )
    if (
        config.interface_api_secret.strip()
        and config.interface_api_secret == config.auth_secret
    ):
        findings.append(
            _finding(
                "SECRET_REUSE",
                "critical",
                "JWT 与接口密钥不能共用同一签名密钥",
            )
        )
    if _looks_insecure_secret(config.auth_default_password, minimum=12):
        findings.append(
            _finding(
                "DEFAULT_ADMIN_PASSWORD",
                "critical",
                "默认管理员密码未替换或少于 12 位",
            )
        )

    for code, url in (
        ("POSTGRES_PASSWORD", config.database_url),
        ("MYSQL_PASSWORD", config.data_mysql_url),
    ):
        if _looks_insecure_secret(_url_password(url), minimum=16):
            findings.append(
                _finding(code, "critical", f"{code} 未替换或强度不足")
            )

    if (config.mysql_host_bind.strip() or "127.0.0.1") not in _LOOPBACK_HOSTS:
        findings.append(
            _finding("MYSQL_PUBLIC_BIND", "critical", "MySQL 不能绑定公网地址")
        )
    if config.data_mysql_direct_access_enabled and not config.data_mysql_ssh_tunnel_required:
        findings.append(
            _finding(
                "DBEAVER_WITHOUT_TUNNEL",
                "critical",
                "启用 DBeaver 管理接入时必须强制 SSH 隧道",
            )
        )

    origins = _csv_values(config.cors_allowed_origins)
    if not origins or "*" in origins:
        findings.append(
            _finding(
                "CORS_WILDCARD",
                "critical" if production else "warning",
                "生产环境必须明确配置允许访问后台的 HTTPS 来源",
            )
        )
    if production and any(
        not origin.startswith("https://")
        and not origin.startswith("http://localhost")
        and not origin.startswith("http://127.0.0.1")
        for origin in origins
    ):
        findings.append(
            _finding(
                "CORS_WITHOUT_HTTPS",
                "critical",
                "生产后台来源必须使用 HTTPS",
            )
        )
    trusted_hosts = _csv_values(config.trusted_hosts)
    if not trusted_hosts or "*" in trusted_hosts:
        findings.append(
            _finding(
                "TRUSTED_HOSTS_WILDCARD",
                "critical" if production else "warning",
                "生产环境必须明确配置可信域名",
            )
        )

    if config.auth_algorithm not in {"HS256", "HS384", "HS512"}:
        findings.append(
            _finding("JWT_ALGORITHM", "critical", "JWT 算法不在允许列表中")
        )
    if not 5 <= config.auth_token_expire_minutes <= 120:
        findings.append(
            _finding(
                "JWT_LIFETIME",
                "critical" if production else "warning",
                "后台登录令牌有效期必须为 5–120 分钟",
            )
        )
    if any(
        _looks_insecure_secret(item, minimum=24)
        for item in _csv_values(config.ingest_api_keys)
    ):
        findings.append(
            _finding(
                "INGEST_API_KEYS",
                "critical" if production else "warning",
                "外部问答接口仍包含开发密钥或弱密钥",
            )
        )

    if not config.data_backup_enabled:
        findings.append(
            _finding("BACKUP_DISABLED", "warning", "尚未声明已启用自动加密备份")
        )
    if not config.data_mysql_audit_enabled:
        findings.append(
            _finding("DB_AUDIT_DISABLED", "warning", "DBeaver 数据库审计尚未启用")
        )

    critical_count = sum(item["severity"] == "critical" for item in findings)
    warning_count = sum(item["severity"] == "warning" for item in findings)
    return {
        "environment": config.app_environment,
        "strict_mode": config.security_strict_mode,
        "status": "blocked" if critical_count else "ready",
        "critical_count": critical_count,
        "warning_count": warning_count,
        "findings": findings,
    }


def enforce_security_baseline(config: Settings = settings) -> None:
    """Abort a strict deployment before it starts with unsafe settings."""

    if not config.security_strict_mode:
        return
    report = security_readiness(config)
    critical = [item for item in report["findings"] if item["severity"] == "critical"]
    if critical:
        codes = ", ".join(item["code"] for item in critical)
        raise RuntimeError(f"生产安全基线检查失败：{codes}")