from fastapi import APIRouter, Depends, HTTPException, UploadFile, File, Form
from sqlalchemy.orm import Session
from sqlalchemy import text
from typing import List, Optional
import os
import shutil
from datetime import datetime
import uuid
import pandas as pd
import re
from pathlib import Path

from ..database import get_db
from app.services.material_classifier import classify_material
router = APIRouter()

UPLOAD_DIR = Path("uploads")
UPLOAD_DIR.mkdir(exist_ok=True)
ALLOWED_EXTENSIONS = {".xlsx", ".xls", ".csv"}

@router.get("/")
async def get_files_info():
    return {
        "message": "파일 관리 API",
        "allowed_extensions": list(ALLOWED_EXTENSIONS),
        "upload_directory": str(UPLOAD_DIR)
    }

@router.get("/test")
async def test_endpoint():
    return {"status": "파일 API가 정상 작동합니다!"}

@router.post("/add-missing-columns")
async def add_missing_columns(db: Session = Depends(get_db)):
    """누락된 컬럼들 추가"""
    try:
        db.execute(text("ALTER TABLE files ADD COLUMN IF NOT EXISTS parsed_count INTEGER DEFAULT 0"))
        db.execute(text("ALTER TABLE materials ADD COLUMN IF NOT EXISTS row_number INTEGER"))
        db.commit()
        
        return {
            "success": True,
            "message": "누락된 컬럼들이 추가되었습니다",
            "added_columns": ["files.parsed_count", "materials.row_number"]
        }
    except Exception as e:
        db.rollback()
        return {"success": False, "error": f"컬럼 추가 실패: {str(e)}"}

def validate_file_extension(filename: str) -> bool:
    return Path(filename).suffix.lower() in ALLOWED_EXTENSIONS

def generate_unique_filename(original_filename: str) -> str:
    timestamp = datetime.now().strftime("%Y%m%d_%H%M%S")
    unique_id = str(uuid.uuid4())[:8]
    stem = Path(original_filename).stem
    suffix = Path(original_filename).suffix
    return f"{stem}_{timestamp}_{unique_id}{suffix}"

def parse_dataframe(df):
    df = df.dropna(how='all')
    df.columns = df.columns.str.strip().str.lower()
    
    column_mapping = {
        'description': ['description', 'item', 'material', '품명', '자재명'],
        'quantity': ['qty', 'quantity', 'ea', '수량'],
        'main_size': ['main_nom', 'nominal_diameter', 'nd', '주배관'],
        'red_size': ['red_nom', 'reduced_diameter', '축소배관'],
        'length': ['length', 'len', '길이'],
        'weight': ['weight', 'wt', '중량'],
        'dwg_name': ['dwg_name', 'drawing', '도면명'],
        'line_num': ['line_num', 'line_number', '라인번호']
    }
    
    mapped_columns = {}
    for standard_col, possible_names in column_mapping.items():
        for possible_name in possible_names:
            if possible_name in df.columns:
                mapped_columns[standard_col] = possible_name
                break
    
    materials = []
    for index, row in df.iterrows():
        description = str(row.get(mapped_columns.get('description', ''), ''))
        quantity_raw = row.get(mapped_columns.get('quantity', ''), 0)
        
        try:
            quantity = float(quantity_raw) if pd.notna(quantity_raw) else 0
        except:
            quantity = 0
        
        material_grade = ""
        if "ASTM" in description.upper():
            astm_match = re.search(r'ASTM\s+([A-Z0-9\s]+)', description.upper())
            if astm_match:
                material_grade = astm_match.group(0).strip()
        
        main_size = str(row.get(mapped_columns.get('main_size', ''), ''))
        red_size = str(row.get(mapped_columns.get('red_size', ''), ''))
        
        if main_size != 'nan' and red_size != 'nan' and red_size != '':
            size_spec = f"{main_size} x {red_size}"
        elif main_size != 'nan' and main_size != '':
            size_spec = main_size
        else:
            size_spec = ""
        
        if description and description not in ['nan', 'None', '']:
            materials.append({
                'original_description': description,
                'quantity': quantity,
                'unit': "EA",
                'size_spec': size_spec,
                'material_grade': material_grade,
                'line_number': index + 1,
                'row_number': index + 1
            })
    
    return materials

def parse_file_data(file_path):
    file_extension = Path(file_path).suffix.lower()
    
    try:
        if file_extension == ".csv":
            df = pd.read_csv(file_path, encoding='utf-8')
        elif file_extension in [".xlsx", ".xls"]:
            df = pd.read_excel(file_path, sheet_name=0)
        else:
            raise HTTPException(status_code=400, detail="지원하지 않는 파일 형식")
        
        return parse_dataframe(df)
    except Exception as e:
        raise HTTPException(status_code=400, detail=f"파일 파싱 실패: {str(e)}")

@router.post("/upload")
async def upload_file(
    file: UploadFile = File(...),
    job_no: str = Form(...),
    revision: str = Form("Rev.0"),
    db: Session = Depends(get_db)
):
    if not validate_file_extension(file.filename):
        raise HTTPException(
            status_code=400, 
            detail=f"지원하지 않는 파일 형식입니다. 허용된 확장자: {', '.join(ALLOWED_EXTENSIONS)}"
        )
    
    if file.size and file.size > 10 * 1024 * 1024:
        raise HTTPException(status_code=400, detail="파일 크기는 10MB를 초과할 수 없습니다")
    
    unique_filename = generate_unique_filename(file.filename)
    file_path = UPLOAD_DIR / unique_filename
    
    try:
        with open(file_path, "wb") as buffer:
            shutil.copyfileobj(file.file, buffer)
    except Exception as e:
        raise HTTPException(status_code=500, detail=f"파일 저장 실패: {str(e)}")
    
    try:
        materials_data = parse_file_data(str(file_path))
        parsed_count = len(materials_data)
        
        # 파일 정보 저장
        file_insert_query = text("""
            INSERT INTO files (filename, original_filename, file_path, job_no, revision, description, file_size, parsed_count, is_active)
            VALUES (:filename, :original_filename, :file_path, :job_no, :revision, :description, :file_size, :parsed_count, :is_active)
            RETURNING id
        """)
        
        file_result = db.execute(file_insert_query, {
            "filename": unique_filename,
            "original_filename": file.filename,
            "file_path": str(file_path),
            "job_no": job_no,
            "revision": revision,
            "description": f"BOM 파일 - {parsed_count}개 자재",
            "file_size": file.size,
            "parsed_count": parsed_count,
            "is_active": True
        })
        
        file_id = file_result.fetchone()[0]
        
        # 자재 데이터 저장
        materials_inserted = 0
        for material_data in materials_data:
            material_insert_query = text("""
                INSERT INTO materials (
                    file_id, original_description, quantity, unit, size_spec, 
                    material_grade, line_number, row_number, classified_category, 
                    classification_confidence, is_verified, created_at
                )
                VALUES (
                    :file_id, :original_description, :quantity, :unit, :size_spec,
                    :material_grade, :line_number, :row_number, :classified_category,
                    :classification_confidence, :is_verified, :created_at
                )
            """)
            
            db.execute(material_insert_query, {
                "file_id": file_id,
                "original_description": material_data["original_description"],
                "quantity": material_data["quantity"],
                "unit": material_data["unit"],
                "size_spec": material_data["size_spec"],
                "material_grade": material_data["material_grade"],
                "line_number": material_data["line_number"],
                "row_number": material_data["row_number"],
                "classified_category": get_major_category(material_data["original_description"]),
                "classification_confidence": 0.9,
                "is_verified": False,
                "created_at": datetime.now()
            })
            materials_inserted += 1
        
        db.commit()
        
        return {
            "success": True,
            "message": f"완전한 DB 저장 성공! {materials_inserted}개 자재 저장됨",
            "original_filename": file.filename,
            "file_id": file_id,
            "parsed_materials_count": parsed_count,
            "saved_materials_count": materials_inserted,
            "sample_materials": materials_data[:3] if materials_data else []
        }
        
    except Exception as e:
        db.rollback()
        if os.path.exists(file_path):
            os.remove(file_path)
        raise HTTPException(status_code=500, detail=f"파일 처리 실패: {str(e)}")
@router.get("/materials")
async def get_materials(
    job_no: Optional[str] = None,
    file_id: Optional[str] = None,
    skip: int = 0,
    limit: int = 100,
    db: Session = Depends(get_db)
):
    """저장된 자재 목록 조회"""
    try:
        query = """
            SELECT m.id, m.file_id, m.original_description, m.quantity, m.unit,
                   m.size_spec, m.material_grade, m.line_number, m.row_number,
                   m.created_at,
                   f.original_filename, f.job_no,
                   j.job_no, j.job_name, m.classified_category, m.classification_confidence
            FROM materials m
            LEFT JOIN files f ON m.file_id = f.id
            LEFT JOIN jobs j ON f.job_no = j.job_no
            WHERE 1=1
        """
        
        params = {}
        
        if job_no:
            query += " AND f.job_no = :job_no"
            params["job_no"] = job_no
        
        if file_id:
            query += " AND m.file_id = :file_id"
            params["file_id"] = file_id
            
        query += " ORDER BY m.line_number ASC LIMIT :limit OFFSET :skip"
        params["limit"] = limit
        params["skip"] = skip
        
        result = db.execute(text(query), params)
        materials = result.fetchall()
        
        # 전체 개수 조회
        count_query = """
            SELECT COUNT(*) as total
            FROM materials m
            LEFT JOIN files f ON m.file_id = f.id
            WHERE 1=1
        """
        count_params = {}
        
        if job_no:
            count_query += " AND f.job_no = :job_no"
            count_params["job_no"] = job_no
        
        if file_id:
            count_query += " AND m.file_id = :file_id"
            count_params["file_id"] = file_id
        
        count_result = db.execute(text(count_query), count_params)
        total_count = count_result.fetchone()[0]
        
        return {
            "success": True,
            "total_count": total_count,
            "returned_count": len(materials),
            "skip": skip,
            "limit": limit,
            "materials": [
                {
                    "id": m.id,
                    "file_id": m.file_id,
                    "filename": m.original_filename,
                    "job_no": row.job_no,
                    "project_code": row.job_no,
                    "project_name": "Job-" + str(f.job_no) if f.job_no else "Unknown",
                    "original_description": row.original_description,
                    "quantity": float(m.quantity) if m.quantity else 0,
                    "unit": m.unit,
                    "classified_category": row.classified_category,
                    "classification_confidence": float(row.classification_confidence) if m.classification_confidence else 0.0,
                    "size_spec": m.size_spec,
                    "material_grade": m.material_grade,
                    "line_number": m.line_number,
                    "row_number": m.row_number,
                    "created_at": m.created_at
                }
                for m in materials
            ]
        }
        
    except Exception as e:
        raise HTTPException(status_code=500, detail=f"자재 조회 실패: {str(e)}")

@router.get("/materials/summary")
async def get_materials_summary(
    job_no: Optional[str] = None,
    file_id: Optional[str] = None,
    db: Session = Depends(get_db)
):
    """자재 요약 통계"""
    try:
        query = """
            SELECT 
                COUNT(*) as total_items,
                COUNT(DISTINCT m.original_description) as unique_descriptions,
                COUNT(DISTINCT m.size_spec) as unique_sizes,
                COUNT(DISTINCT m.material_grade) as unique_materials,
                SUM(m.quantity) as total_quantity,
                AVG(m.quantity) as avg_quantity,
                MIN(m.created_at) as earliest_upload,
                MAX(m.created_at) as latest_upload
            FROM materials m
            LEFT JOIN files f ON m.file_id = f.id
            WHERE 1=1
        """
        
        params = {}
        
        if job_no:
            query += " AND f.job_no = :job_no"
            params["job_no"] = job_no
        
        if file_id:
            query += " AND m.file_id = :file_id"
            params["file_id"] = file_id
        
        result = db.execute(text(query), params)
        summary = result.fetchone()
        
        return {
            "success": True,
            "summary": {
                "total_items": summary.total_items,
                "unique_descriptions": summary.unique_descriptions,
                "unique_sizes": summary.unique_sizes,
                "unique_materials": summary.unique_materials,
                "total_quantity": float(summary.total_quantity) if summary.total_quantity else 0,
                "avg_quantity": round(float(summary.avg_quantity), 2) if summary.avg_quantity else 0,
                "earliest_upload": summary.earliest_upload,
                "latest_upload": summary.latest_upload
            }
        }
        
    except Exception as e:
        raise HTTPException(status_code=500, detail=f"요약 조회 실패: {str(e)}")
# Job 검증 함수 (파일 끝에 추가할 예정)
async def validate_job_exists(job_no: str, db: Session):
    """Job 존재 여부 및 활성 상태 확인"""
    try:
        query = text("SELECT job_no, job_name, status FROM jobs WHERE job_no = :job_no AND is_active = true")
        job = db.execute(query, {"job_no": job_no}).fetchone()
        
        if not job:
            return {"valid": False, "error": f"Job No. '{job_no}'를 찾을 수 없습니다"}
        
        if job.status == '완료':
            return {"valid": False, "error": f"완료된 Job '{job.job_name}'에는 파일을 업로드할 수 없습니다"}
        
        return {
            "valid": True,
            "job": {
                "job_no": job.job_no,
                "job_name": job.job_name,
                "status": job.status
            }
        }
        
    except Exception as e:
        return {"valid": False, "error": f"Job 검증 실패: {str(e)}"}
def get_major_category(description):
    """간단한 키워드 기반 대분류"""
    desc_upper = description.upper()
    
    if 'PIPE' in desc_upper or 'TUBE' in desc_upper:
        return 'pipe'
    elif any(word in desc_upper for word in ['ELBOW', 'ELL', 'TEE', 'REDUCER', 'CAP', 'COUPLING']):
        return 'fitting'
    elif 'VALVE' in desc_upper:
        return 'valve'
    elif 'FLANGE' in desc_upper or 'FLG' in desc_upper:
        return 'flange'
    elif any(word in desc_upper for word in ['GAUGE', 'SENSOR', 'INSTRUMENT', 'TRANSMITTER']):
        return 'instrument'
    elif 'GASKET' in desc_upper or 'GASK' in desc_upper:
        return 'gasket'
    elif any(word in desc_upper for word in ['BOLT', 'STUD', 'NUT', 'SCREW']):
        return 'bolt'
    else:
        return 'other'