from fastapi import APIRouter, Depends
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy import select
from pydantic import BaseModel
from app.core.database import get_db
from app.core.deps import get_current_user, require_roles
from app.models.user import User
from app.models.setting import SystemSetting
from app.services.audit import log_audit

router = APIRouter(prefix="/settings", tags=["系统设置"])

# Default settings — used when keys are missing from DB
DEFAULTS: dict[str, str] = {
    "platform_name": "天普零碳园区智慧能源管理平台",
    "data_retention_days": "365",
    "alarm_auto_resolve_minutes": "30",
    "simulator_interval_seconds": "15",
    "notification_email_enabled": "false",
    "notification_email_smtp": "",
    "report_auto_schedule_enabled": "false",
    "timezone": "Asia/Shanghai",
}


class SettingsUpdate(BaseModel):
    platform_name: str | None = None
    data_retention_days: int | None = None
    alarm_auto_resolve_minutes: int | None = None
    simulator_interval_seconds: int | None = None
    notification_email_enabled: bool | None = None
    notification_email_smtp: str | None = None
    report_auto_schedule_enabled: bool | None = None
    timezone: str | None = None


@router.get("")
async def get_settings(
    db: AsyncSession = Depends(get_db),
    user: User = Depends(get_current_user),
):
    """Return all platform settings as a flat dict."""
    result = await db.execute(select(SystemSetting))
    db_settings = {s.key: s.value for s in result.scalars().all()}
    # Merge defaults with DB values
    merged = {**DEFAULTS, **db_settings}
    # Cast types for frontend
    return {
        "platform_name": merged["platform_name"],
        "data_retention_days": int(merged["data_retention_days"]),
        "alarm_auto_resolve_minutes": int(merged["alarm_auto_resolve_minutes"]),
        "simulator_interval_seconds": int(merged["simulator_interval_seconds"]),
        "notification_email_enabled": merged["notification_email_enabled"] == "true",
        "notification_email_smtp": merged["notification_email_smtp"],
        "report_auto_schedule_enabled": merged["report_auto_schedule_enabled"] == "true",
        "timezone": merged["timezone"],
    }


@router.put("")
async def update_settings(
    data: SettingsUpdate,
    db: AsyncSession = Depends(get_db),
    user: User = Depends(require_roles("admin")),
):
    """Update platform settings (admin only)."""
    updates = data.model_dump(exclude_unset=True)
    changed_keys = []
    for key, value in updates.items():
        str_value = str(value).lower() if isinstance(value, bool) else str(value)
        result = await db.execute(select(SystemSetting).where(SystemSetting.key == key))
        setting = result.scalar_one_or_none()
        if setting:
            setting.value = str_value
        else:
            db.add(SystemSetting(key=key, value=str_value))
        changed_keys.append(key)

    await log_audit(
        db, user.id, "update", "system",
        detail=f"更新系统设置: {', '.join(changed_keys)}",
    )

    return {"message": "设置已更新"}