"""
구매 관리 API
- 구매 품목 생성/조회
- 구매 수량 계산
- 리비전 비교
"""

from fastapi import APIRouter, Depends, HTTPException, Query
from sqlalchemy.orm import Session
from sqlalchemy import text
from typing import List, Optional
import json

from ..database import get_db
from ..services.purchase_calculator import (
    generate_purchase_items_from_materials,
    save_purchase_items_to_db,
    calculate_pipe_purchase_quantity,
    calculate_standard_purchase_quantity
)

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

@router.get("/items/calculate")
async def calculate_purchase_items(
    job_no: str = Query(..., description="Job 번호"),
    revision: str = Query("Rev.0", description="리비전"),
    file_id: Optional[int] = Query(None, description="파일 ID (선택사항)"),
    db: Session = Depends(get_db)
):
    """
    구매 품목 계산 (실시간)
    - 자재 데이터로부터 구매 품목 생성
    - 수량 계산 (파이프 절단손실 포함)
    """
    try:
        # 1. 파일 ID 조회 (job_no, revision으로)
        if not file_id:
            file_query = text("""
                SELECT id FROM files 
                WHERE job_no = :job_no AND revision = :revision AND is_active = TRUE
                ORDER BY created_at DESC
                LIMIT 1
            """)
            file_result = db.execute(file_query, {"job_no": job_no, "revision": revision}).fetchone()
            if not file_result:
                raise HTTPException(status_code=404, detail=f"Job {job_no} {revision}에 해당하는 파일을 찾을 수 없습니다")
            file_id = file_result[0]
        
        # 2. 구매 품목 생성
        purchase_items = generate_purchase_items_from_materials(db, file_id, job_no, revision)
        
        return {
            "success": True,
            "job_no": job_no,
            "revision": revision,
            "file_id": file_id,
            "items": purchase_items,
            "total_items": len(purchase_items)
        }
        
    except Exception as e:
        raise HTTPException(status_code=500, detail=f"구매 품목 계산 실패: {str(e)}")

@router.post("/items/save")
async def save_purchase_items(
    job_no: str,
    revision: str,
    file_id: int,
    db: Session = Depends(get_db)
):
    """
    구매 품목을 데이터베이스에 저장
    """
    try:
        # 1. 구매 품목 생성
        purchase_items = generate_purchase_items_from_materials(db, file_id, job_no, revision)
        
        # 2. 데이터베이스에 저장
        saved_ids = save_purchase_items_to_db(db, purchase_items)
        
        return {
            "success": True,
            "message": f"{len(saved_ids)}개 구매 품목이 저장되었습니다",
            "saved_items": len(saved_ids),
            "item_ids": saved_ids
        }
        
    except Exception as e:
        db.rollback()
        raise HTTPException(status_code=500, detail=f"구매 품목 저장 실패: {str(e)}")

@router.get("/items")
async def get_purchase_items(
    job_no: str = Query(..., description="Job 번호"),
    revision: str = Query("Rev.0", description="리비전"),
    category: Optional[str] = Query(None, description="카테고리 필터"),
    db: Session = Depends(get_db)
):
    """
    저장된 구매 품목 조회
    """
    try:
        query = text("""
            SELECT pi.*, 
                   COUNT(mpm.material_id) as material_count,
                   SUM(m.quantity) as total_material_quantity
            FROM purchase_items pi
            LEFT JOIN material_purchase_mapping mpm ON pi.id = mpm.purchase_item_id
            LEFT JOIN materials m ON mpm.material_id = m.id
            WHERE pi.job_no = :job_no AND pi.revision = :revision AND pi.is_active = TRUE
        """)
        
        params = {"job_no": job_no, "revision": revision}
        
        if category:
            query = text(str(query) + " AND pi.category = :category")
            params["category"] = category
        
        query = text(str(query) + """
            GROUP BY pi.id
            ORDER BY pi.category, pi.specification
        """)
        
        result = db.execute(query, params)
        items = result.fetchall()
        
        return {
            "success": True,
            "job_no": job_no,
            "revision": revision,
            "items": [dict(item) for item in items],
            "total_items": len(items)
        }
        
    except Exception as e:
        raise HTTPException(status_code=500, detail=f"구매 품목 조회 실패: {str(e)}")

@router.patch("/items/{item_id}")
async def update_purchase_item(
    item_id: int,
    safety_factor: Optional[float] = None,
    calculated_qty: Optional[float] = None,
    minimum_order_qty: Optional[float] = None,
    db: Session = Depends(get_db)
):
    """
    구매 품목 수정 (수량 조정)
    """
    try:
        update_fields = []
        params = {"item_id": item_id}
        
        if safety_factor is not None:
            update_fields.append("safety_factor = :safety_factor")
            params["safety_factor"] = safety_factor
        
        if calculated_qty is not None:
            update_fields.append("calculated_qty = :calculated_qty")
            params["calculated_qty"] = calculated_qty
        
        if minimum_order_qty is not None:
            update_fields.append("minimum_order_qty = :minimum_order_qty")
            params["minimum_order_qty"] = minimum_order_qty
        
        if not update_fields:
            raise HTTPException(status_code=400, detail="수정할 필드가 없습니다")
        
        update_fields.append("updated_at = CURRENT_TIMESTAMP")
        
        query = text(f"""
            UPDATE purchase_items 
            SET {', '.join(update_fields)}
            WHERE id = :item_id
            RETURNING id, calculated_qty, safety_factor
        """)
        
        result = db.execute(query, params)
        updated_item = result.fetchone()
        
        if not updated_item:
            raise HTTPException(status_code=404, detail="구매 품목을 찾을 수 없습니다")
        
        db.commit()
        
        return {
            "success": True,
            "message": "구매 품목이 수정되었습니다",
            "item": dict(updated_item)
        }
        
    except Exception as e:
        db.rollback()
        raise HTTPException(status_code=500, detail=f"구매 품목 수정 실패: {str(e)}")

@router.get("/revision-diff")
async def get_revision_diff(
    job_no: str = Query(..., description="Job 번호"),
    current_revision: str = Query(..., description="현재 리비전"),
    previous_revision: str = Query(..., description="이전 리비전"),
    db: Session = Depends(get_db)
):
    """
    리비전간 구매 수량 차이 계산
    """
    try:
        # 1. 이전 리비전 구매 품목 조회
        prev_query = text("""
            SELECT item_code, category, specification, calculated_qty, bom_quantity
            FROM purchase_items
            WHERE job_no = :job_no AND revision = :prev_revision AND is_active = TRUE
        """)
        prev_items = db.execute(prev_query, {
            "job_no": job_no, 
            "prev_revision": previous_revision
        }).fetchall()
        
        # 2. 현재 리비전 구매 품목 조회
        curr_query = text("""
            SELECT item_code, category, specification, calculated_qty, bom_quantity
            FROM purchase_items
            WHERE job_no = :job_no AND revision = :curr_revision AND is_active = TRUE
        """)
        curr_items = db.execute(curr_query, {
            "job_no": job_no,
            "curr_revision": current_revision
        }).fetchall()
        
        # 3. 차이 계산
        prev_dict = {item.item_code: dict(item) for item in prev_items}
        curr_dict = {item.item_code: dict(item) for item in curr_items}
        
        changes = []
        added_items = 0
        modified_items = 0
        
        # 현재 리비전에서 추가되거나 변경된 항목
        for item_code, curr_item in curr_dict.items():
            if item_code not in prev_dict:
                # 새로 추가된 품목
                changes.append({
                    "item_code": item_code,
                    "change_type": "ADDED",
                    "specification": curr_item["specification"],
                    "previous_qty": 0,
                    "current_qty": curr_item["calculated_qty"],
                    "qty_diff": curr_item["calculated_qty"],
                    "additional_needed": curr_item["calculated_qty"]
                })
                added_items += 1
            else:
                prev_item = prev_dict[item_code]
                qty_diff = curr_item["calculated_qty"] - prev_item["calculated_qty"]
                
                if abs(qty_diff) > 0.001:  # 수량 변경
                    changes.append({
                        "item_code": item_code,
                        "change_type": "MODIFIED",
                        "specification": curr_item["specification"],
                        "previous_qty": prev_item["calculated_qty"],
                        "current_qty": curr_item["calculated_qty"],
                        "qty_diff": qty_diff,
                        "additional_needed": max(qty_diff, 0)  # 증가한 경우만 추가 구매
                    })
                    modified_items += 1
        
        # 삭제된 품목 (현재 리비전에 없는 항목)
        removed_items = 0
        for item_code, prev_item in prev_dict.items():
            if item_code not in curr_dict:
                changes.append({
                    "item_code": item_code,
                    "change_type": "REMOVED",
                    "specification": prev_item["specification"],
                    "previous_qty": prev_item["calculated_qty"],
                    "current_qty": 0,
                    "qty_diff": -prev_item["calculated_qty"],
                    "additional_needed": 0
                })
                removed_items += 1
        
        # 요약 정보
        total_additional_needed = sum(
            change["additional_needed"] for change in changes 
            if change["additional_needed"] > 0
        )
        
        has_changes = len(changes) > 0
        
        summary = f"추가: {added_items}개, 변경: {modified_items}개, 삭제: {removed_items}개"
        if total_additional_needed > 0:
            summary += f" (추가 구매 필요: {total_additional_needed:.1f})"
        
        return {
            "success": True,
            "job_no": job_no,
            "previous_revision": previous_revision,
            "current_revision": current_revision,
            "comparison": {
                "has_changes": has_changes,
                "summary": summary,
                "added_items": added_items,
                "modified_items": modified_items,
                "removed_items": removed_items,
                "total_additional_needed": total_additional_needed,
                "changes": changes
            }
        }
        
    except Exception as e:
        raise HTTPException(status_code=500, detail=f"리비전 비교 실패: {str(e)}")

@router.post("/orders/create")
async def create_purchase_order(
    job_no: str,
    revision: str,
    items: List[dict],
    supplier_name: Optional[str] = None,
    required_date: Optional[str] = None,
    db: Session = Depends(get_db)
):
    """
    구매 주문 생성
    """
    try:
        from datetime import datetime, date
        
        # 1. 주문 번호 생성
        order_no = f"PO-{job_no}-{revision}-{datetime.now().strftime('%Y%m%d')}"
        
        # 2. 구매 주문 생성
        order_query = text("""
            INSERT INTO purchase_orders (
                order_no, job_no, revision, status, order_date, required_date,
                supplier_name, created_by
            ) VALUES (
                :order_no, :job_no, :revision, 'DRAFT', CURRENT_DATE, :required_date,
                :supplier_name, 'system'
            ) RETURNING id
        """)
        
        order_result = db.execute(order_query, {
            "order_no": order_no,
            "job_no": job_no,
            "revision": revision,
            "required_date": required_date,
            "supplier_name": supplier_name
        })
        
        order_id = order_result.fetchone()[0]
        
        # 3. 주문 상세 항목 생성
        total_amount = 0
        for item in items:
            item_query = text("""
                INSERT INTO purchase_order_items (
                    purchase_order_id, purchase_item_id, ordered_quantity, required_date
                ) VALUES (
                    :order_id, :item_id, :quantity, :required_date
                )
            """)
            
            db.execute(item_query, {
                "order_id": order_id,
                "item_id": item["purchase_item_id"],
                "quantity": item["ordered_quantity"],
                "required_date": required_date
            })
        
        db.commit()
        
        return {
            "success": True,
            "message": "구매 주문이 생성되었습니다",
            "order_no": order_no,
            "order_id": order_id,
            "items_count": len(items)
        }
        
    except Exception as e:
        db.rollback()
        raise HTTPException(status_code=500, detail=f"구매 주문 생성 실패: {str(e)}")

@router.get("/orders")
async def get_purchase_orders(
    job_no: Optional[str] = Query(None, description="Job 번호"),
    status: Optional[str] = Query(None, description="주문 상태"),
    db: Session = Depends(get_db)
):
    """
    구매 주문 목록 조회
    """
    try:
        query = text("""
            SELECT po.*, 
                   COUNT(poi.id) as items_count,
                   SUM(poi.ordered_quantity) as total_quantity
            FROM purchase_orders po
            LEFT JOIN purchase_order_items poi ON po.id = poi.purchase_order_id
            WHERE 1=1
        """)
        
        params = {}
        
        if job_no:
            query = text(str(query) + " AND po.job_no = :job_no")
            params["job_no"] = job_no
        
        if status:
            query = text(str(query) + " AND po.status = :status")
            params["status"] = status
        
        query = text(str(query) + """
            GROUP BY po.id
            ORDER BY po.created_at DESC
        """)
        
        result = db.execute(query, params)
        orders = result.fetchall()
        
        return {
            "success": True,
            "orders": [dict(order) for order in orders],
            "total_orders": len(orders)
        }
        
    except Exception as e:
        raise HTTPException(status_code=500, detail=f"구매 주문 조회 실패: {str(e)}")