import os
import shutil
import zipfile
from pathlib import Path
from fastapi import APIRouter, Depends, UploadFile, File, HTTPException, BackgroundTasks
from sqlalchemy.ext.asyncio import AsyncSession

from app.core.database import get_db
from app.core.security import get_current_user
from app.core.config import settings
from app.models.user import User
from app.workers.tasks import process_activity_file, process_garmin_health_zip

router = APIRouter()

ALLOWED_EXTENSIONS = {".fit", ".gpx", ".zip"}
MAX_FILE_SIZE = 500 * 1024 * 1024  # 500 MB


def save_upload(upload: UploadFile, dest_dir: Path) -> Path:
    dest_dir.mkdir(parents=True, exist_ok=True)
    dest = dest_dir / upload.filename
    with open(dest, "wb") as f:
        shutil.copyfileobj(upload.file, f)
    return dest


@router.post("/activity")
async def upload_activity(
    file: UploadFile = File(...),
    background_tasks: BackgroundTasks = None,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    """Upload a single .fit or .gpx activity file."""
    suffix = Path(file.filename).suffix.lower()
    if suffix not in {".fit", ".gpx"}:
        raise HTTPException(status_code=400, detail="Only .fit and .gpx files are supported")

    dest_dir = Path(settings.file_store_path) / str(current_user.id) / "activities"
    dest = save_upload(file, dest_dir)

    # Queue processing
    task = process_activity_file.delay(str(dest), current_user.id, suffix[1:])

    return {"task_id": task.id, "status": "queued", "filename": file.filename}


@router.post("/garmin-export")
async def upload_garmin_export(
    file: UploadFile = File(...),
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    """
    Upload a full Garmin Connect data export ZIP.
    Processes all FIT files for activities + wellness data.
    """
    if not file.filename.endswith(".zip"):
        raise HTTPException(status_code=400, detail="Please upload a .zip Garmin export")

    dest_dir = Path(settings.file_store_path) / str(current_user.id) / "exports"
    dest = save_upload(file, dest_dir)

    # Extract and queue all FIT files
    extract_dir = dest_dir / f"garmin_{dest.stem}"
    extract_dir.mkdir(exist_ok=True)

    task_ids = []
    with zipfile.ZipFile(dest) as zf:
        zf.extractall(extract_dir)
        for name in zf.namelist():
            lower = name.lower()
            if lower.endswith(".fit"):
                fit_path = extract_dir / name
                task = process_activity_file.delay(str(fit_path), current_user.id, "fit")
                task_ids.append(task.id)

    # Queue health/wellness data extraction
    health_task = process_garmin_health_zip.delay(str(dest), current_user.id)

    return {
        "status": "queued",
        "activity_tasks": len(task_ids),
        "task_id": health_task.id,
    }


@router.post("/strava-export")
async def upload_strava_export(
    file: UploadFile = File(...),
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    """Upload a Strava bulk export ZIP (contains activities/ folder with GPX/FIT files)."""
    if not file.filename.endswith(".zip"):
        raise HTTPException(status_code=400, detail="Please upload a .zip Strava export")

    dest_dir = Path(settings.file_store_path) / str(current_user.id) / "exports"
    dest = save_upload(file, dest_dir)

    extract_dir = dest_dir / f"strava_{dest.stem}"
    extract_dir.mkdir(exist_ok=True)

    task_ids = []
    with zipfile.ZipFile(dest) as zf:
        zf.extractall(extract_dir)
        for name in zf.namelist():
            lower = name.lower()
            if lower.endswith(".fit") or lower.endswith(".gpx"):
                file_path = extract_dir / name
                ext = Path(name).suffix[1:]
                task = process_activity_file.delay(str(file_path), current_user.id, ext)
                task_ids.append(task.id)

    return {
        "status": "queued",
        "activity_tasks": len(task_ids),
        "task_id": task_ids[-1] if task_ids else None,
    }


@router.get("/task/{task_id}")
async def check_task_status(
    task_id: str,
    current_user: User = Depends(get_current_user),
):
    """Check the status of an upload processing task."""
    from app.workers.celery_app import celery_app
    result = celery_app.AsyncResult(task_id)
    return {
        "task_id": task_id,
        "status": result.status,
        "result": result.result if result.ready() else None,
    }