from fastapi import APIRouter, Depends, HTTPException, Query, UploadFile, File, Response
from sqlalchemy.ext.asyncio import AsyncSession
from typing import Optional, List
from app.database import get_db
from app.services.customer import CustomerService
from app.services.customer_health import CustomerHealthService
from app.services.import_service import import_service
from app.services.usage import UsageService
from app.services import export
from app.core.security import decode_token
from app.api.v1.deps import get_current_user_id

router = APIRouter()


@router.get("")
async def list_customers(
    status: Optional[str] = None,
    page: int = Query(1, ge=1),
    size: int = Query(20, ge=1, le=1000),
    user_id: str = Depends(get_current_user_id),
    db: AsyncSession = Depends(get_db),
):
    service = CustomerService(db)
    return await service.list_customers(user_id, status, page, size)


@router.get("/silent")
async def get_silent(
    days: int = Query(3, ge=1),
    user_id: str = Depends(get_current_user_id),
    db: AsyncSession = Depends(get_db),
):
    service = CustomerService(db)
    customers = await service.get_silent_customers(user_id, days)
    return {
        "customers": customers,
        "count": len(customers),
        "silence_days": days,
    }


@router.get("/health-overview")
async def get_health_overview(
    user_id: str = Depends(get_current_user_id),
    db: AsyncSession = Depends(get_db),
):
    service = CustomerHealthService(db)
    return await service.get_health_overview(user_id)


@router.get("/health-scores")
async def get_all_health_scores(
    user_id: str = Depends(get_current_user_id),
    db: AsyncSession = Depends(get_db),
):
    service = CustomerHealthService(db)
    return {"items": await service.get_all_health_scores(user_id)}


@router.get("/{customer_id}/health")
async def get_customer_health(
    customer_id: str,
    user_id: str = Depends(get_current_user_id),
    db: AsyncSession = Depends(get_db),
):
    service = CustomerHealthService(db)
    return await service.get_customer_health(user_id, customer_id)


@router.get("/{customer_id}/conversation")
async def get_conversation(
    customer_id: str,
    page: int = 1,
    size: int = 20,
    user_id: str = Depends(get_current_user_id),
    db: AsyncSession = Depends(get_db),
):
    service = CustomerService(db)
    return await service.get_conversation(user_id, customer_id, page, size)


@router.get("/{customer_id}")
async def get_customer(
    customer_id: str,
    user_id: str = Depends(get_current_user_id),
    db: AsyncSession = Depends(get_db),
):
    service = CustomerService(db)
    customer = await service.get_customer(user_id, customer_id)
    if not customer:
        raise HTTPException(status_code=404, detail="Customer not found")
    return customer


@router.post("")
async def create_customer(
    data: dict,
    user_id: str = Depends(get_current_user_id),
    db: AsyncSession = Depends(get_db),
):
    usage = UsageService(db)
    ok, msg = await usage.check_quota(user_id, "create_customer")
    if not ok:
        raise HTTPException(status_code=429, detail=msg)
    service = CustomerService(db)
    customer = await service.create_customer(user_id, data)
    await usage.record_usage(user_id, "create_customer")
    return customer


@router.patch("/{customer_id}")
async def update_customer(
    customer_id: str,
    data: dict,
    user_id: str = Depends(get_current_user_id),
    db: AsyncSession = Depends(get_db),
):
    service = CustomerService(db)
    customer = await service.update_customer(user_id, customer_id, data)
    if not customer:
        raise HTTPException(status_code=404, detail="Customer not found")
    return customer


@router.delete("/{customer_id}")
async def delete_customer(
    customer_id: str,
    user_id: str = Depends(get_current_user_id),
    db: AsyncSession = Depends(get_db),
):
    service = CustomerService(db)
    deleted = await service.delete_customer(user_id, customer_id)
    if not deleted:
        raise HTTPException(status_code=404, detail="Customer not found")
    return {"message": "Customer deleted"}


MAX_UPLOAD_SIZE = 10 * 1024 * 1024  # 10MB

@router.post("/import")
async def import_customers(
    file: UploadFile = File(...),
    user_id: str = Depends(get_current_user_id),
    db: AsyncSession = Depends(get_db),
):
    from app.workers.tasks import process_customer_import

    filename = file.filename or "unknown"
    file_size = 0
    content = b""
    while True:
        chunk = await file.read(8192)
        if not chunk:
            break
        file_size += len(chunk)
        if file_size > MAX_UPLOAD_SIZE:
            raise HTTPException(status_code=413, detail=f"File too large. Max {MAX_UPLOAD_SIZE // (1024*1024)}MB")
        content += chunk

    if filename.endswith(".xlsx"):
        records, parse_errors = import_service.parse_xlsx(content)
    elif filename.endswith(".csv"):
        records, parse_errors = import_service.parse_csv(content)
    else:
        raise HTTPException(status_code=400, detail="Unsupported file format. Use .xlsx or .csv")

    if parse_errors and not records:
        raise HTTPException(status_code=400, detail="Parse failed. Check file format.")

    valid, validation_errors = import_service.validate_records(records)
    all_errors = parse_errors + validation_errors
    imported_count = 0

    for record in valid:
        try:
            svc = CustomerService(db)
            await svc.create_customer(user_id, record)
            imported_count += 1
        except Exception as e:
            all_errors.append(f"Import failed for row: {str(e)}")

    return {
        "imported": imported_count,
        "total": len(records),
        "errors": all_errors,
        "filename": filename,
    }


@router.get("/export/csv")
async def export_customers(
    status: Optional[str] = None,
    user_id: str = Depends(get_current_user_id),
    db: AsyncSession = Depends(get_db),
):
    service = CustomerService(db)
    result = await service.list_customers(user_id, status, 1, 9999)
    items = result.get("items", [])
    csv_bytes = export.export_customers_csv(items)
    return Response(
        content=csv_bytes,
        media_type="text/csv",
        headers={"Content-Disposition": "attachment; filename=customers.csv"},
    )


@router.get("/export/xlsx")
async def export_customers_xlsx(
    status: Optional[str] = None,
    user_id: str = Depends(get_current_user_id),
    db: AsyncSession = Depends(get_db),
):
    service = CustomerService(db)
    result = await service.list_customers(user_id, status, 1, 9999)
    items = result.get("items", [])
    xlsx_bytes = export.export_customers_xlsx(items)
    return Response(
        content=xlsx_bytes,
        media_type="application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
        headers={"Content-Disposition": "attachment; filename=customers.xlsx"},
    )