from datetime import datetime, timedelta
from pathlib import Path
import os
import shutil
from fastapi import APIRouter, Depends
from sqlalchemy.orm import Session
from sqlalchemy import func
from redis import Redis

from app.core.db import get_db
from app.core.redis import get_redis
from app.schemas.dashboard import DashboardSummary, UserStats, StorageStats, ServerStats
from app.models import User


router = APIRouter(prefix="/dashboard", tags=["dashboard"])


AUDIO_EXTENSIONS = {".mp3", ".wav", ".m4a", ".flac", ".aac", ".ogg"}


def _get_base_dir() -> Path:
    return Path(__file__).resolve().parents[5]


def _scan_storage(storage_dir: Path) -> tuple[int, int]:
    total_bytes = 0
    file_count = 0
    if not storage_dir.exists():
        return 0, 0
    for root, _dirs, files in os.walk(storage_dir):
        for name in files:
            file_path = Path(root) / name
            try:
                total_bytes += file_path.stat().st_size
            except OSError:
                continue
            file_count += 1
    return total_bytes, file_count


def _get_cpu_memory() -> tuple[float, float]:
    try:
        import psutil  # type: ignore
        cpu = psutil.cpu_percent(interval=0.2)
        mem = psutil.virtual_memory().percent
        return float(cpu), float(mem)
    except Exception:
        return 0.0, 0.0


def _get_disk_usage(path: Path) -> float:
    try:
        total, used, _free = shutil.disk_usage(path)
        if total == 0:
            return 0.0
        return round(used / total * 100, 2)
    except Exception:
        return 0.0


@router.get("/summary", response_model=DashboardSummary)
def get_dashboard_summary(db: Session = Depends(get_db), redis: Redis = Depends(get_redis)):
    total_users = db.query(User).filter(User.is_deleted == 0).count()
    
    # 2. 今日新增
    today_start = datetime.now().replace(hour=0, minute=0, second=0, microsecond=0)
    new_today = db.query(User).filter(
        User.created_at >= today_start,
        User.is_deleted == 0
    ).count()

    try:
        online = len(redis.keys("auth:online:*"))
    except Exception:
        online = 0

    base_dir = _get_base_dir()
    storage_dir = base_dir / "storage"
    total_bytes, audio_files = _scan_storage(storage_dir)
    total_gb = round(total_bytes / (1024 ** 3), 2)

    cpu, mem = _get_cpu_memory()
    disk = _get_disk_usage(storage_dir if storage_dir.exists() else base_dir)

    return DashboardSummary(
        users=UserStats(total=total_users, new_today=new_today, online=online),
        storage=StorageStats(total_gb=total_gb, audio_files=audio_files),
        server=ServerStats(cpu=cpu, memory=mem, disk=disk),
    )