"""
자재 비교 및 발주 추적 API
- 리비전간 자재 비교
- 추가 발주 필요량 계산
- 발주 상태 관리
"""

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

from ..database import get_db

router = APIRouter(prefix="/materials", tags=["material-comparison"])

@router.post("/compare-revisions")
async def compare_material_revisions(
    job_no: str,
    current_revision: str,
    previous_revision: Optional[str] = None,
    save_result: bool = True,
    db: Session = Depends(get_db)
):
    """
    리비전간 자재 비교 및 추가 발주 필요량 계산
    - 해시 기반 고성능 비교
    - 누적 재고 고려한 실제 구매 필요량 계산
    """
    try:
        # 1. 파일 정보 조회
        current_file = await get_file_by_revision(db, job_no, current_revision)
        if not current_file:
            raise HTTPException(status_code=404, detail=f"{job_no} {current_revision} 파일을 찾을 수 없습니다")
        
        # 2. 이전 리비전 자동 탐지
        if not previous_revision:
            previous_revision = await get_previous_revision(db, job_no, current_revision)
        
        previous_file = None
        if previous_revision:
            previous_file = await get_file_by_revision(db, job_no, previous_revision)
        
        # 3. 자재 비교 실행
        comparison_result = await perform_material_comparison(
            db, current_file, previous_file, job_no
        )
        
        # 4. 결과 저장 (선택사항)
        comparison_id = None
        if save_result and previous_file and previous_revision:
            comparison_id = await save_comparison_result(
                db, job_no, current_revision, previous_revision,
                current_file["id"], previous_file["id"], comparison_result
            )
        
        return {
            "success": True,
            "job_no": job_no,
            "current_revision": current_revision,
            "previous_revision": previous_revision,
            "comparison_id": comparison_id,
            "summary": comparison_result["summary"],
            "new_items": comparison_result["new_items"],
            "modified_items": comparison_result["modified_items"],
            "removed_items": comparison_result["removed_items"],
            "purchase_summary": comparison_result["purchase_summary"]
        }
        
    except Exception as e:
        raise HTTPException(status_code=500, detail=f"자재 비교 실패: {str(e)}")

@router.get("/comparison-history")
async def get_comparison_history(
    job_no: str = Query(..., description="Job 번호"),
    limit: int = Query(10, ge=1, le=50),
    db: Session = Depends(get_db)
):
    """
    자재 비교 이력 조회
    """
    try:
        query = text("""
            SELECT 
                id, current_revision, previous_revision,
                new_items_count, modified_items_count, removed_items_count,
                            upload_date, created_by
        FROM material_revisions_comparison 
        WHERE job_no = :job_no 
        ORDER BY upload_date DESC
            LIMIT :limit
        """)
        
        result = db.execute(query, {"job_no": job_no, "limit": limit})
        comparisons = result.fetchall()
        
        return {
            "success": True,
            "job_no": job_no,
            "comparisons": [
                {
                    "id": comp[0],
                    "current_revision": comp[1],
                    "previous_revision": comp[2],
                    "new_items_count": comp[3],
                    "modified_items_count": comp[4],
                    "removed_items_count": comp[5],
                    "upload_date": comp[6],
                    "created_by": comp[7]
                }
                for comp in comparisons
            ]
        }
        
    except Exception as e:
        raise HTTPException(status_code=500, detail=f"비교 이력 조회 실패: {str(e)}")

@router.get("/inventory-status")
async def get_material_inventory_status(
    job_no: str = Query(..., description="Job 번호"),
    material_hash: Optional[str] = Query(None, description="특정 자재 해시"),
    db: Session = Depends(get_db)
):
    """
    자재별 누적 재고 현황 조회
    """
    try:
        # 임시로 빈 결과 반환 (추후 개선)
        return {
            "success": True,
            "job_no": job_no,
            "inventory": []
        }
        
    except Exception as e:
        raise HTTPException(status_code=500, detail=f"재고 현황 조회 실패: {str(e)}")

@router.post("/confirm-purchase")
async def confirm_material_purchase(
    job_no: str,
    revision: str,
    confirmations: List[Dict],
    confirmed_by: str = "system",
    db: Session = Depends(get_db)
):
    """
    자재 발주 확정 처리
    confirmations = [
        {
            "material_hash": "abc123",
            "confirmed_quantity": 100,
            "supplier_name": "ABC공급업체",
            "unit_price": 1000
        }
    ]
    """
    try:
        confirmed_items = []
        
        for confirmation in confirmations:
            # 발주 추적 테이블에 저장/업데이트
            upsert_query = text("""
                INSERT INTO material_purchase_tracking (
                    job_no, material_hash, revision, description, size_spec, unit,
                    bom_quantity, calculated_quantity, confirmed_quantity,
                    purchase_status, supplier_name, unit_price, total_price,
                    confirmed_by, confirmed_at
                )
                SELECT 
                    :job_no, m.material_hash, :revision, m.original_description, 
                    m.size_spec, m.unit, m.quantity, :calculated_qty, :confirmed_qty,
                    'CONFIRMED', :supplier_name, :unit_price, :total_price,
                    :confirmed_by, CURRENT_TIMESTAMP
                FROM materials m
                WHERE m.material_hash = :material_hash
                AND m.file_id = (
                    SELECT id FROM files 
                    WHERE job_no = :job_no AND revision = :revision 
                    ORDER BY upload_date DESC LIMIT 1
                )
                LIMIT 1
                ON CONFLICT (job_no, material_hash, revision)
                DO UPDATE SET
                    confirmed_quantity = :confirmed_qty,
                    purchase_status = 'CONFIRMED',
                    supplier_name = :supplier_name,
                    unit_price = :unit_price,
                    total_price = :total_price,
                    confirmed_by = :confirmed_by,
                    confirmed_at = CURRENT_TIMESTAMP,
                    updated_at = CURRENT_TIMESTAMP
                RETURNING id, description, confirmed_quantity
            """)
            
            calculated_qty = confirmation.get("calculated_quantity", confirmation["confirmed_quantity"])
            total_price = confirmation["confirmed_quantity"] * confirmation.get("unit_price", 0)
            
            result = db.execute(upsert_query, {
                "job_no": job_no,
                "revision": revision,
                "material_hash": confirmation["material_hash"],
                "calculated_qty": calculated_qty,
                "confirmed_qty": confirmation["confirmed_quantity"],
                "supplier_name": confirmation.get("supplier_name", ""),
                "unit_price": confirmation.get("unit_price", 0),
                "total_price": total_price,
                "confirmed_by": confirmed_by
            })
            
            confirmed_item = result.fetchone()
            if confirmed_item:
                confirmed_items.append({
                    "id": confirmed_item[0],
                    "material_hash": confirmed_item[1], 
                    "confirmed_quantity": confirmed_item[2],
                    "supplier_name": confirmed_item[3],
                    "unit_price": confirmed_item[4],
                    "total_price": confirmed_item[5]
                })
        
        db.commit()
        
        return {
            "success": True,
            "message": f"{len(confirmed_items)}개 자재 발주가 확정되었습니다",
            "confirmed_items": confirmed_items,
            "job_no": job_no,
            "revision": revision
        }
        
    except Exception as e:
        db.rollback()
        raise HTTPException(status_code=500, detail=f"발주 확정 실패: {str(e)}")

@router.get("/purchase-status")
async def get_purchase_status(
    job_no: str = Query(..., description="Job 번호"),
    revision: Optional[str] = Query(None, description="리비전 (전체 조회시 생략)"),
    status: Optional[str] = Query(None, description="발주 상태 필터"),
    db: Session = Depends(get_db)
):
    """
    발주 상태 조회
    """
    try:
        where_conditions = ["job_no = :job_no"]
        params = {"job_no": job_no}
        
        if revision:
            where_conditions.append("revision = :revision")
            params["revision"] = revision
            
        if status:
            where_conditions.append("purchase_status = :status")
            params["status"] = status
        
        query = text(f"""
            SELECT 
                material_hash, revision, description, size_spec, unit,
                bom_quantity, calculated_quantity, confirmed_quantity,
                purchase_status, supplier_name, unit_price, total_price,
                order_date, delivery_date, confirmed_by, confirmed_at
            FROM material_purchase_tracking
            WHERE {' AND '.join(where_conditions)}
            ORDER BY revision DESC, description
        """)
        
        result = db.execute(query, params)
        purchases = result.fetchall()
        
        # 상태별 요약
        status_summary = {}
        total_amount = 0
        
        for purchase in purchases:
            status_key = purchase.purchase_status
            if status_key not in status_summary:
                status_summary[status_key] = {"count": 0, "total_amount": 0}
            
            status_summary[status_key]["count"] += 1
            status_summary[status_key]["total_amount"] += purchase.total_price or 0
            total_amount += purchase.total_price or 0
        
        return {
            "success": True,
            "job_no": job_no,
            "revision": revision,
            "purchases": [purchase._asdict() if hasattr(purchase, '_asdict') else dict(zip(purchase.keys(), purchase)) for purchase in purchases],
            "summary": {
                "total_items": len(purchases),
                "total_amount": total_amount,
                "status_breakdown": status_summary
            }
        }
        
    except Exception as e:
        raise HTTPException(status_code=500, detail=f"발주 상태 조회 실패: {str(e)}")

# ========== 헬퍼 함수들 ==========

async def get_file_by_revision(db: Session, job_no: str, revision: str) -> Optional[Dict]:
    """리비전으로 파일 정보 조회"""
    query = text("""
                SELECT id, original_filename, revision, upload_date
        FROM files 
        WHERE job_no = :job_no AND revision = :revision AND is_active = TRUE
        ORDER BY upload_date DESC
        LIMIT 1
    """)
    
    result = db.execute(query, {"job_no": job_no, "revision": revision})
    file_row = result.fetchone()
    
    if file_row:
        return {
            "id": file_row[0],
            "original_filename": file_row[1], 
            "revision": file_row[2],
            "upload_date": file_row[3]
        }
    return None

async def get_previous_revision(db: Session, job_no: str, current_revision: str) -> Optional[str]:
    """이전 리비전 자동 탐지"""
    query = text("""
        SELECT revision
        FROM files
        WHERE job_no = :job_no AND revision < :current_revision AND is_active = TRUE
        ORDER BY revision DESC
        LIMIT 1
    """)
    
    result = db.execute(query, {"job_no": job_no, "current_revision": current_revision})
    prev_row = result.fetchone()
    
    if prev_row is not None:
        return prev_row[0]
    return None

async def perform_material_comparison(
    db: Session, 
    current_file: Dict, 
    previous_file: Optional[Dict],
    job_no: str
) -> Dict:
    """
    핵심 자재 비교 로직
    - 해시 기반 고성능 비교
    - 누적 재고 고려한 실제 구매 필요량 계산
    """
    
    # 1. 현재 리비전 자재 목록 (해시별로 그룹화)
    current_materials = await get_materials_by_hash(db, current_file["id"])
    
    # 2. 이전 리비전 자재 목록
    previous_materials = {}
    if previous_file:
        previous_materials = await get_materials_by_hash(db, previous_file["id"])
    
    # 3. 현재까지의 누적 재고 조회
    current_inventory = await get_current_inventory(db, job_no)
    
    # 4. 비교 실행
    new_items = []
    modified_items = []
    removed_items = []
    purchase_summary = {
        "additional_purchase_needed": 0,
        "total_new_items": 0,
        "total_increased_items": 0
    }
    
    # 신규/변경 항목 찾기
    for material_hash, current_item in current_materials.items():
        current_qty = current_item["quantity"]
        available_stock = current_inventory.get(material_hash, 0)
        
        if material_hash not in previous_materials:
            # 완전히 새로운 항목
            additional_needed = max(current_qty - available_stock, 0)
            
            new_items.append({
                "material_hash": material_hash,
                "description": current_item["description"],
                "size_spec": current_item["size_spec"],
                "material_grade": current_item["material_grade"],
                "quantity": current_qty,
                "available_stock": available_stock,
                "additional_needed": additional_needed
            })
            
            purchase_summary["additional_purchase_needed"] += additional_needed
            purchase_summary["total_new_items"] += 1
            
        else:
            # 기존 항목 - 수량 변경 체크
            previous_qty = previous_materials[material_hash]["quantity"]
            qty_diff = current_qty - previous_qty
            
            if qty_diff != 0:
                additional_needed = max(current_qty - available_stock, 0)
                
                modified_items.append({
                    "material_hash": material_hash,
                    "description": current_item["description"],
                    "size_spec": current_item["size_spec"],
                    "previous_quantity": previous_qty,
                    "current_quantity": current_qty,
                    "quantity_diff": qty_diff,
                    "available_stock": available_stock,
                    "additional_needed": additional_needed
                })
                
                if additional_needed > 0:
                    purchase_summary["additional_purchase_needed"] += additional_needed
                    purchase_summary["total_increased_items"] += 1
    
    # 삭제된 항목 찾기
    for material_hash, previous_item in previous_materials.items():
        if material_hash not in current_materials:
            removed_items.append({
                "material_hash": material_hash,
                "description": previous_item["description"],
                "size_spec": previous_item["size_spec"],
                "quantity": previous_item["quantity"]
            })
    
    return {
        "summary": {
            "total_current_items": len(current_materials),
            "total_previous_items": len(previous_materials),
            "new_items_count": len(new_items),
            "modified_items_count": len(modified_items),
            "removed_items_count": len(removed_items)
        },
        "new_items": new_items,
        "modified_items": modified_items,
        "removed_items": removed_items,
        "purchase_summary": purchase_summary
    }

async def get_materials_by_hash(db: Session, file_id: int) -> Dict[str, Dict]:
    """파일의 자재를 해시별로 그룹화하여 조회"""
    import hashlib
    
    query = text("""
        SELECT 
            original_description,
            size_spec,
            material_grade,
            SUM(quantity) as quantity,
            classified_category
        FROM materials
        WHERE file_id = :file_id
        GROUP BY original_description, size_spec, material_grade, classified_category
    """)
    
    result = db.execute(query, {"file_id": file_id})
    materials = result.fetchall()
    
    materials_dict = {}
    for mat in materials:
        # 자재 해시 생성 (description + size_spec + material_grade)
        hash_source = f"{mat[0] or ''}|{mat[1] or ''}|{mat[2] or ''}"
        material_hash = hashlib.md5(hash_source.encode()).hexdigest()
        
        materials_dict[material_hash] = {
            "material_hash": material_hash,
            "original_description": mat[0],
            "size_spec": mat[1],
            "material_grade": mat[2],
            "quantity": float(mat[3]) if mat[3] else 0.0,
            "classified_category": mat[4]
        }
    
    return materials_dict

async def get_current_inventory(db: Session, job_no: str) -> Dict[str, float]:
    """현재까지의 누적 재고량 조회"""
    query = text("""
        SELECT material_hash, available_stock
        FROM material_inventory_status
        WHERE job_no = :job_no
    """)
    
    result = db.execute(query, {"job_no": job_no})
    inventory = result.fetchall()
    
    return {inv.material_hash: float(inv.available_stock or 0) for inv in inventory}

async def save_comparison_result(
    db: Session,
    job_no: str,
    current_revision: str,
    previous_revision: str,
    current_file_id: int,
    previous_file_id: int,
    comparison_result: Dict
) -> int:
    """비교 결과를 데이터베이스에 저장"""
    
    # 메인 비교 레코드 저장
    insert_query = text("""
        INSERT INTO material_revisions_comparison (
            job_no, current_revision, previous_revision,
            current_file_id, previous_file_id,
            total_current_items, total_previous_items,
            new_items_count, modified_items_count, removed_items_count,
            comparison_details, created_by
        ) VALUES (
            :job_no, :current_revision, :previous_revision,
            :current_file_id, :previous_file_id,
            :total_current_items, :total_previous_items,
            :new_items_count, :modified_items_count, :removed_items_count,
            :comparison_details, 'system'
        )
        ON CONFLICT (job_no, current_revision, previous_revision)
        DO UPDATE SET
            total_current_items = :total_current_items,
            total_previous_items = :total_previous_items,
            new_items_count = :new_items_count,
            modified_items_count = :modified_items_count,
            removed_items_count = :removed_items_count,
            comparison_details = :comparison_details,
            upload_date = CURRENT_TIMESTAMP
        RETURNING id
    """)
    
    import json
    summary = comparison_result["summary"]
    
    result = db.execute(insert_query, {
        "job_no": job_no,
        "current_revision": current_revision,
        "previous_revision": previous_revision,
        "current_file_id": current_file_id,
        "previous_file_id": previous_file_id,
        "total_current_items": summary["total_current_items"],
        "total_previous_items": summary["total_previous_items"],
        "new_items_count": summary["new_items_count"],
        "modified_items_count": summary["modified_items_count"],
        "removed_items_count": summary["removed_items_count"],
        "comparison_details": json.dumps(comparison_result, ensure_ascii=False)
    })
    
    comparison_id = result.fetchone()[0]
    db.commit()
    
    return comparison_id