from fastapi import APIRouter, Depends, HTTPException
from sqlalchemy.orm import Session
from sqlalchemy import desc
from datetime import datetime
from typing import List, Optional

from ..database import get_db
from ..models import User
from ..models.inquiry import Inquiry, InquiryMessage, InquiryStatus
from ..schemas.inquiry import (
    InquiryCreate, InquiryResponse, InquiryListResponse,
    InquiryMessageCreate, InquiryMessageResponse, InquiryWithMessages,
    AdminInquiryRespond, AdminInquiryUpdateStatus
)
from .auth import get_current_user
from .notification import create_notification

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


# =====================
# User Endpoints
# =====================

@router.get("", response_model=List[InquiryResponse])
def get_inquiries(
    current_user: User = Depends(get_current_user),
    db: Session = Depends(get_db)
):
    """Get current user's inquiries (legacy endpoint)"""
    return db.query(Inquiry).filter(Inquiry.user_id == current_user.id).order_by(desc(Inquiry.created_at)).all()


@router.post("", response_model=InquiryResponse)
def create_inquiry(
    inquiry_data: InquiryCreate,
    current_user: User = Depends(get_current_user),
    db: Session = Depends(get_db)
):
    """Create a new inquiry"""
    inquiry = Inquiry(
        user_id=current_user.id,
        car_id=inquiry_data.car_id,
        category=inquiry_data.category,
        subject=inquiry_data.subject or f"{inquiry_data.category} 문의",
        message=inquiry_data.message,
        contact_email=inquiry_data.contact_email or current_user.email,
        contact_phone=inquiry_data.contact_phone or current_user.phone,
        status=InquiryStatus.PENDING
    )

    db.add(inquiry)
    db.commit()
    db.refresh(inquiry)

    return inquiry


@router.get("/my-inquiries", response_model=InquiryListResponse)
def get_my_inquiries(
    page: int = 1,
    page_size: int = 10,
    status: Optional[str] = None,
    current_user: User = Depends(get_current_user),
    db: Session = Depends(get_db)
):
    """Get current user's inquiries with pagination"""
    query = db.query(Inquiry).filter(Inquiry.user_id == current_user.id)

    if status:
        query = query.filter(Inquiry.status == status)

    total = query.count()
    inquiries = query.order_by(desc(Inquiry.created_at)) \
        .offset((page - 1) * page_size) \
        .limit(page_size) \
        .all()

    return InquiryListResponse(
        inquiries=[InquiryResponse.model_validate(i) for i in inquiries],
        total=total
    )


@router.get("/my-inquiries/{inquiry_id}", response_model=InquiryWithMessages)
def get_my_inquiry_detail(
    inquiry_id: int,
    current_user: User = Depends(get_current_user),
    db: Session = Depends(get_db)
):
    """Get details of a specific inquiry with messages"""
    inquiry = db.query(Inquiry).filter(
        Inquiry.id == inquiry_id,
        Inquiry.user_id == current_user.id
    ).first()

    if not inquiry:
        raise HTTPException(status_code=404, detail="Inquiry not found")

    messages = db.query(InquiryMessage).filter(
        InquiryMessage.inquiry_id == inquiry_id
    ).order_by(InquiryMessage.created_at).all()

    return InquiryWithMessages(
        inquiry=InquiryResponse.model_validate(inquiry),
        messages=[InquiryMessageResponse.model_validate(m) for m in messages]
    )


@router.post("/my-inquiries/{inquiry_id}/message", response_model=InquiryMessageResponse)
def add_message_to_inquiry(
    inquiry_id: int,
    message_data: InquiryMessageCreate,
    current_user: User = Depends(get_current_user),
    db: Session = Depends(get_db)
):
    """Add a message to an existing inquiry"""
    inquiry = db.query(Inquiry).filter(
        Inquiry.id == inquiry_id,
        Inquiry.user_id == current_user.id
    ).first()

    if not inquiry:
        raise HTTPException(status_code=404, detail="Inquiry not found")

    if inquiry.status == InquiryStatus.CLOSED:
        raise HTTPException(status_code=400, detail="Cannot add message to closed inquiry")

    message = InquiryMessage(
        inquiry_id=inquiry_id,
        user_id=current_user.id,
        message=message_data.message,
        is_admin=False
    )

    # Update inquiry status if it was resolved
    if inquiry.status == InquiryStatus.RESOLVED:
        inquiry.status = InquiryStatus.IN_PROGRESS

    db.add(message)
    db.commit()
    db.refresh(message)

    return message


@router.get("/{inquiry_id}", response_model=InquiryResponse)
def get_inquiry(
    inquiry_id: int,
    current_user: User = Depends(get_current_user),
    db: Session = Depends(get_db)
):
    """Get inquiry detail (legacy endpoint)"""
    inquiry = db.query(Inquiry).filter(
        Inquiry.id == inquiry_id,
        Inquiry.user_id == current_user.id
    ).first()
    if not inquiry:
        raise HTTPException(status_code=404, detail="Inquiry not found")
    return inquiry


# =====================
# Admin Endpoints
# =====================

@router.get("/admin/list", response_model=InquiryListResponse)
def admin_get_all_inquiries(
    page: int = 1,
    page_size: int = 20,
    status: Optional[str] = None,
    category: Optional[str] = None,
    current_user: User = Depends(get_current_user),
    db: Session = Depends(get_db)
):
    """[Admin] Get all inquiries"""
    if not current_user.is_admin:
        raise HTTPException(status_code=403, detail="Admin access required")

    query = db.query(Inquiry)

    if status:
        query = query.filter(Inquiry.status == status)
    if category:
        query = query.filter(Inquiry.category == category)

    total = query.count()
    inquiries = query.order_by(desc(Inquiry.created_at)) \
        .offset((page - 1) * page_size) \
        .limit(page_size) \
        .all()

    return InquiryListResponse(
        inquiries=[InquiryResponse.model_validate(i) for i in inquiries],
        total=total
    )


@router.get("/admin/{inquiry_id}", response_model=InquiryWithMessages)
def admin_get_inquiry_detail(
    inquiry_id: int,
    current_user: User = Depends(get_current_user),
    db: Session = Depends(get_db)
):
    """[Admin] Get inquiry details with messages"""
    if not current_user.is_admin:
        raise HTTPException(status_code=403, detail="Admin access required")

    inquiry = db.query(Inquiry).filter(Inquiry.id == inquiry_id).first()

    if not inquiry:
        raise HTTPException(status_code=404, detail="Inquiry not found")

    messages = db.query(InquiryMessage).filter(
        InquiryMessage.inquiry_id == inquiry_id
    ).order_by(InquiryMessage.created_at).all()

    return InquiryWithMessages(
        inquiry=InquiryResponse.model_validate(inquiry),
        messages=[InquiryMessageResponse.model_validate(m) for m in messages]
    )


@router.post("/admin/{inquiry_id}/respond", response_model=InquiryMessageResponse)
def admin_respond_to_inquiry(
    inquiry_id: int,
    response_data: AdminInquiryRespond,
    current_user: User = Depends(get_current_user),
    db: Session = Depends(get_db)
):
    """[Admin] Respond to an inquiry"""
    if not current_user.is_admin:
        raise HTTPException(status_code=403, detail="Admin access required")

    inquiry = db.query(Inquiry).filter(Inquiry.id == inquiry_id).first()

    if not inquiry:
        raise HTTPException(status_code=404, detail="Inquiry not found")

    # Create message
    message = InquiryMessage(
        inquiry_id=inquiry_id,
        user_id=current_user.id,
        message=response_data.message,
        is_admin=True
    )

    # Update inquiry
    inquiry.admin_response = response_data.message
    inquiry.responded_at = datetime.utcnow()
    inquiry.responded_by = current_user.id

    if response_data.status:
        inquiry.status = response_data.status
    elif inquiry.status == InquiryStatus.PENDING:
        inquiry.status = InquiryStatus.IN_PROGRESS

    db.add(message)
    db.commit()
    db.refresh(message)

    # Send notification to user
    create_notification(
        db=db,
        user_id=inquiry.user_id,
        notification_type="system",
        title="문의 답변 도착",
        message=f"'{inquiry.subject}' 문의에 답변이 등록되었습니다.",
        link="/contact"
    )

    return message


@router.put("/admin/{inquiry_id}/status", response_model=InquiryResponse)
def admin_update_inquiry_status(
    inquiry_id: int,
    status_data: AdminInquiryUpdateStatus,
    current_user: User = Depends(get_current_user),
    db: Session = Depends(get_db)
):
    """[Admin] Update inquiry status"""
    if not current_user.is_admin:
        raise HTTPException(status_code=403, detail="Admin access required")

    inquiry = db.query(Inquiry).filter(Inquiry.id == inquiry_id).first()

    if not inquiry:
        raise HTTPException(status_code=404, detail="Inquiry not found")

    valid_statuses = [InquiryStatus.PENDING, InquiryStatus.IN_PROGRESS, InquiryStatus.RESOLVED, InquiryStatus.CLOSED]
    if status_data.status not in valid_statuses:
        raise HTTPException(
            status_code=400,
            detail=f"Invalid status. Must be one of: {valid_statuses}"
        )

    inquiry.status = status_data.status
    db.commit()
    db.refresh(inquiry)

    return inquiry


@router.get("/admin/stats")
def admin_get_inquiry_stats(
    current_user: User = Depends(get_current_user),
    db: Session = Depends(get_db)
):
    """[Admin] Get inquiry statistics"""
    if not current_user.is_admin:
        raise HTTPException(status_code=403, detail="Admin access required")

    total = db.query(Inquiry).count()
    pending = db.query(Inquiry).filter(Inquiry.status == InquiryStatus.PENDING).count()
    in_progress = db.query(Inquiry).filter(Inquiry.status == InquiryStatus.IN_PROGRESS).count()
    resolved = db.query(Inquiry).filter(Inquiry.status == InquiryStatus.RESOLVED).count()
    closed = db.query(Inquiry).filter(Inquiry.status == InquiryStatus.CLOSED).count()

    return {
        "total": total,
        "pending": pending,
        "in_progress": in_progress,
        "resolved": resolved,
        "closed": closed
    }