# app/api/v1/admin/vendors.py
"""
Vendor management endpoints for admin.
"""

import logging
from typing import Optional

from fastapi import APIRouter, Depends, Query, Path, Body
from sqlalchemy.orm import Session

from app.api.deps import get_current_admin_user
from app.core.database import get_db
from app.services.admin_service import admin_service
from app.services.stats_service import stats_service
from app.exceptions import VendorNotFoundException, ConfirmationRequiredException
from models.schema.stats import VendorStatsResponse
from models.schema.vendor import (
    VendorListResponse,
    VendorResponse,
    VendorDetailResponse,
    VendorCreate,
    VendorCreateResponse,
    VendorUpdate,
    VendorTransferOwnership,
    VendorTransferOwnershipResponse,
)
from models.database.user import User
from models.database.vendor import Vendor
from sqlalchemy import func

router = APIRouter(prefix="/vendors")
logger = logging.getLogger(__name__)


def _get_vendor_by_identifier(db: Session, identifier: str) -> Vendor:
    """
    Helper to get vendor by ID or vendor_code.
    Follows the pattern from admin_service._get_vendor_by_id_or_raise.

    Args:
        db: Database session
        identifier: Either vendor ID (int as string) or vendor_code (string)

    Returns:
        Vendor object

    Raises:
        VendorNotFoundException: If vendor not found
    """
    # Try as integer ID first
    try:
        vendor_id = int(identifier)
        return admin_service.get_vendor_by_id(db, vendor_id)
    except (ValueError, TypeError):
        # Not an integer, treat as vendor_code
        pass
    except VendorNotFoundException:
        # ID not found, try as vendor_code
        pass

    # Try as vendor_code (case-insensitive)
    vendor = db.query(Vendor).filter(
        func.upper(Vendor.vendor_code) == identifier.upper()
    ).first()

    if not vendor:
        raise VendorNotFoundException(identifier, identifier_type="code")

    return vendor


@router.post("", response_model=VendorCreateResponse)
def create_vendor_with_owner(
        vendor_data: VendorCreate,
        db: Session = Depends(get_db),
        current_admin: User = Depends(get_current_admin_user),
):
    """
    Create a new vendor with owner user account (Admin only).

    This endpoint:
    1. Creates a new vendor record
    2. Creates an owner user account with owner_email
    3. Sets contact_email (defaults to owner_email if not provided)
    4. Sets up default roles (Owner, Manager, Editor, Viewer)
    5. Returns credentials (temporary password shown ONCE)

    **Email Fields:**
    - `owner_email`: Used for owner's login/authentication (stored in users.email)
    - `contact_email`: Public business contact (stored in vendors.contact_email)

    Returns vendor details with owner credentials.
    """
    vendor, owner_user, temp_password = admin_service.create_vendor_with_owner(
        db=db,
        vendor_data=vendor_data
    )

    return VendorCreateResponse(
        # Vendor fields
        id=vendor.id,
        vendor_code=vendor.vendor_code,
        subdomain=vendor.subdomain,
        name=vendor.name,
        description=vendor.description,
        owner_user_id=vendor.owner_user_id,
        contact_email=vendor.contact_email,
        contact_phone=vendor.contact_phone,
        website=vendor.website,
        business_address=vendor.business_address,
        tax_number=vendor.tax_number,
        letzshop_csv_url_fr=vendor.letzshop_csv_url_fr,
        letzshop_csv_url_en=vendor.letzshop_csv_url_en,
        letzshop_csv_url_de=vendor.letzshop_csv_url_de,
        is_active=vendor.is_active,
        is_verified=vendor.is_verified,
        created_at=vendor.created_at,
        updated_at=vendor.updated_at,
        # Owner credentials
        owner_email=owner_user.email,
        owner_username=owner_user.username,
        temporary_password=temp_password,
        login_url=f"http://localhost:8000/vendor/{vendor.subdomain}/login"
    )


@router.get("", response_model=VendorListResponse)
def get_all_vendors_admin(
        skip: int = Query(0, ge=0),
        limit: int = Query(100, ge=1, le=1000),
        search: Optional[str] = Query(None, description="Search by name or vendor code"),
        is_active: Optional[bool] = Query(None),
        is_verified: Optional[bool] = Query(None),
        db: Session = Depends(get_db),
        current_admin: User = Depends(get_current_admin_user),
):
    """Get all vendors with filtering (Admin only)."""
    vendors, total = admin_service.get_all_vendors(
        db=db,
        skip=skip,
        limit=limit,
        search=search,
        is_active=is_active,
        is_verified=is_verified
    )
    return VendorListResponse(vendors=vendors, total=total, skip=skip, limit=limit)


@router.get("/stats", response_model=VendorStatsResponse)
def get_vendor_statistics_endpoint(
        db: Session = Depends(get_db),
        current_admin: User = Depends(get_current_admin_user),
):
    """Get vendor statistics for admin dashboard (Admin only)."""
    stats = stats_service.get_vendor_statistics(db)

    return VendorStatsResponse(
        total=stats.get("total_vendors", 0),
        verified=stats.get("verified_vendors", 0),
        pending=stats.get("pending_vendors", 0),
        inactive=stats.get("inactive_vendors", 0),
    )


@router.get("/{vendor_identifier}", response_model=VendorDetailResponse)
def get_vendor_details(
        vendor_identifier: str = Path(..., description="Vendor ID or vendor_code"),
        db: Session = Depends(get_db),
        current_admin: User = Depends(get_current_admin_user),
):
    """
    Get detailed vendor information including owner details (Admin only).

    Accepts either vendor ID (integer) or vendor_code (string).

    Returns both:
    - `contact_email` (business contact)
    - `owner_email` (owner's authentication email)
    """
    vendor = _get_vendor_by_identifier(db, vendor_identifier)

    return VendorDetailResponse(
        # Vendor fields
        id=vendor.id,
        vendor_code=vendor.vendor_code,
        subdomain=vendor.subdomain,
        name=vendor.name,
        description=vendor.description,
        owner_user_id=vendor.owner_user_id,
        contact_email=vendor.contact_email,
        contact_phone=vendor.contact_phone,
        website=vendor.website,
        business_address=vendor.business_address,
        tax_number=vendor.tax_number,
        letzshop_csv_url_fr=vendor.letzshop_csv_url_fr,
        letzshop_csv_url_en=vendor.letzshop_csv_url_en,
        letzshop_csv_url_de=vendor.letzshop_csv_url_de,
        is_active=vendor.is_active,
        is_verified=vendor.is_verified,
        created_at=vendor.created_at,
        updated_at=vendor.updated_at,
        # Owner details
        owner_email=vendor.owner.email,
        owner_username=vendor.owner.username,
    )


@router.put("/{vendor_identifier}", response_model=VendorDetailResponse)
def update_vendor(
        vendor_identifier: str = Path(..., description="Vendor ID or vendor_code"),
        vendor_update: VendorUpdate = Body(...),
        db: Session = Depends(get_db),
        current_admin: User = Depends(get_current_admin_user),
):
    """
    Update vendor information (Admin only).

    Accepts either vendor ID (integer) or vendor_code (string).

    **Can update:**
    - Basic info: name, description, subdomain
    - Business contact: contact_email, contact_phone, website
    - Business details: business_address, tax_number
    - Marketplace URLs
    - Status: is_active, is_verified

    **Cannot update:**
    - `owner_email` (use POST /vendors/{id}/transfer-ownership)
    - `vendor_code` (immutable)
    - `owner_user_id` (use POST /vendors/{id}/transfer-ownership)
    """
    vendor = _get_vendor_by_identifier(db, vendor_identifier)
    vendor = admin_service.update_vendor(db, vendor.id, vendor_update)

    return VendorDetailResponse(
        id=vendor.id,
        vendor_code=vendor.vendor_code,
        subdomain=vendor.subdomain,
        name=vendor.name,
        description=vendor.description,
        owner_user_id=vendor.owner_user_id,
        contact_email=vendor.contact_email,
        contact_phone=vendor.contact_phone,
        website=vendor.website,
        business_address=vendor.business_address,
        tax_number=vendor.tax_number,
        letzshop_csv_url_fr=vendor.letzshop_csv_url_fr,
        letzshop_csv_url_en=vendor.letzshop_csv_url_en,
        letzshop_csv_url_de=vendor.letzshop_csv_url_de,
        is_active=vendor.is_active,
        is_verified=vendor.is_verified,
        created_at=vendor.created_at,
        updated_at=vendor.updated_at,
        owner_email=vendor.owner.email,
        owner_username=vendor.owner.username,
    )


@router.post("/{vendor_identifier}/transfer-ownership", response_model=VendorTransferOwnershipResponse)
def transfer_vendor_ownership(
        vendor_identifier: str = Path(..., description="Vendor ID or vendor_code"),
        transfer_data: VendorTransferOwnership = Body(...),
        db: Session = Depends(get_db),
        current_admin: User = Depends(get_current_admin_user),
):
    """
    Transfer vendor ownership to another user (Admin only).

    Accepts either vendor ID (integer) or vendor_code (string).

    **This is a critical operation that:**
    - Changes the owner_user_id
    - Assigns new owner to "Owner" role
    - Demotes old owner to "Manager" role (or removes them)
    - Creates audit trail

    ⚠️ **This action is logged and should be used carefully.**

    **Requires:**
    - `new_owner_user_id`: ID of user who will become owner
    - `confirm_transfer`: Must be true
    - `transfer_reason`: Optional reason for audit trail
    """
    from datetime import datetime, timezone

    vendor = _get_vendor_by_identifier(db, vendor_identifier)
    vendor, old_owner, new_owner = admin_service.transfer_vendor_ownership(
        db, vendor.id, transfer_data
    )

    return VendorTransferOwnershipResponse(
        message="Ownership transferred successfully",
        vendor_id=vendor.id,
        vendor_code=vendor.vendor_code,
        vendor_name=vendor.name,
        old_owner={
            "id": old_owner.id,
            "username": old_owner.username,
            "email": old_owner.email,
        },
        new_owner={
            "id": new_owner.id,
            "username": new_owner.username,
            "email": new_owner.email,
        },
        transferred_at=datetime.now(timezone.utc),
        transfer_reason=transfer_data.transfer_reason,
    )


@router.put("/{vendor_identifier}/verification", response_model=VendorDetailResponse)
def toggle_vendor_verification(
        vendor_identifier: str = Path(..., description="Vendor ID or vendor_code"),
        verification_data: dict = Body(..., example={"is_verified": True}),
        db: Session = Depends(get_db),
        current_admin: User = Depends(get_current_admin_user),
):
    """
    Toggle vendor verification status (Admin only).

    Accepts either vendor ID (integer) or vendor_code (string).

    Request body: { "is_verified": true/false }
    """
    vendor = _get_vendor_by_identifier(db, vendor_identifier)

    # Use admin_service method if available, otherwise update directly
    if "is_verified" in verification_data:
        try:
            vendor, message = admin_service.verify_vendor(db, vendor.id)
            logger.info(f"Vendor verification toggled: {message}")
        except AttributeError:
            # If verify_vendor method doesn't exist, update directly
            vendor.is_verified = verification_data["is_verified"]
            db.commit()
            db.refresh(vendor)

    return VendorDetailResponse(
        id=vendor.id,
        vendor_code=vendor.vendor_code,
        subdomain=vendor.subdomain,
        name=vendor.name,
        description=vendor.description,
        owner_user_id=vendor.owner_user_id,
        contact_email=vendor.contact_email,
        contact_phone=vendor.contact_phone,
        website=vendor.website,
        business_address=vendor.business_address,
        tax_number=vendor.tax_number,
        letzshop_csv_url_fr=vendor.letzshop_csv_url_fr,
        letzshop_csv_url_en=vendor.letzshop_csv_url_en,
        letzshop_csv_url_de=vendor.letzshop_csv_url_de,
        is_active=vendor.is_active,
        is_verified=vendor.is_verified,
        created_at=vendor.created_at,
        updated_at=vendor.updated_at,
        owner_email=vendor.owner.email,
        owner_username=vendor.owner.username,
    )


@router.put("/{vendor_identifier}/status", response_model=VendorDetailResponse)
def toggle_vendor_status(
        vendor_identifier: str = Path(..., description="Vendor ID or vendor_code"),
        status_data: dict = Body(..., example={"is_active": True}),
        db: Session = Depends(get_db),
        current_admin: User = Depends(get_current_admin_user),
):
    """
    Toggle vendor active status (Admin only).

    Accepts either vendor ID (integer) or vendor_code (string).

    Request body: { "is_active": true/false }
    """
    vendor = _get_vendor_by_identifier(db, vendor_identifier)

    # Use admin_service method if available, otherwise update directly
    if "is_active" in status_data:
        try:
            vendor, message = admin_service.toggle_vendor_status(db, vendor.id)
            logger.info(f"Vendor status toggled: {message}")
        except AttributeError:
            # If toggle_vendor_status method doesn't exist, update directly
            vendor.is_active = status_data["is_active"]
            db.commit()
            db.refresh(vendor)

    return VendorDetailResponse(
        id=vendor.id,
        vendor_code=vendor.vendor_code,
        subdomain=vendor.subdomain,
        name=vendor.name,
        description=vendor.description,
        owner_user_id=vendor.owner_user_id,
        contact_email=vendor.contact_email,
        contact_phone=vendor.contact_phone,
        website=vendor.website,
        business_address=vendor.business_address,
        tax_number=vendor.tax_number,
        letzshop_csv_url_fr=vendor.letzshop_csv_url_fr,
        letzshop_csv_url_en=vendor.letzshop_csv_url_en,
        letzshop_csv_url_de=vendor.letzshop_csv_url_de,
        is_active=vendor.is_active,
        is_verified=vendor.is_verified,
        created_at=vendor.created_at,
        updated_at=vendor.updated_at,
        owner_email=vendor.owner.email,
        owner_username=vendor.owner.username,
    )


@router.delete("/{vendor_identifier}")
def delete_vendor(
        vendor_identifier: str = Path(..., description="Vendor ID or vendor_code"),
        confirm: bool = Query(False, description="Must be true to confirm deletion"),
        db: Session = Depends(get_db),
        current_admin: User = Depends(get_current_admin_user),
):
    """
    Delete vendor and all associated data (Admin only).

    Accepts either vendor ID (integer) or vendor_code (string).

    ⚠️ **WARNING: This is destructive and will delete:**
    - Vendor account
    - All products
    - All orders
    - All customers
    - All team members

    Requires confirmation parameter: `confirm=true`
    """
    # Raise custom exception instead of HTTPException
    if not confirm:
        raise ConfirmationRequiredException(
            operation="delete_vendor",
            message="Deletion requires confirmation parameter: confirm=true"
        )

    vendor = _get_vendor_by_identifier(db, vendor_identifier)
    message = admin_service.delete_vendor(db, vendor.id)
    return {"message": message}