"""
구매 수량 계산 서비스
- 자재별 여유율 적용
- PIPE: 절단 손실 + 6M 단위 계산
- 기타: 최소 주문 수량 적용
"""

import math
from typing import Dict, List, Tuple
from sqlalchemy.orm import Session
from sqlalchemy import text

# 자재별 기본 여유율
SAFETY_FACTORS = {
    'PIPE': 1.15,        # 15% 추가 (절단 손실)
    'FITTING': 1.10,     # 10% 추가 (연결 오차)
    'VALVE': 1.50,       # 50% 추가 (예비품)
    'FLANGE': 1.10,      # 10% 추가
    'BOLT': 1.20,        # 20% 추가 (분실율)
    'GASKET': 1.25,      # 25% 추가 (교체주기)
    'INSTRUMENT': 1.00,  # 0% 추가 (정확한 수량)
    'DEFAULT': 1.10      # 기본 10% 추가
}

# 최소 주문 수량 (자재별)
MINIMUM_ORDER_QTY = {
    'PIPE': 6000,        # 6M 단위
    'FITTING': 1,        # 개별 주문 가능
    'VALVE': 1,          # 개별 주문 가능
    'FLANGE': 1,         # 개별 주문 가능
    'BOLT': 50,          # 박스 단위 (50개)
    'GASKET': 10,        # 세트 단위
    'INSTRUMENT': 1,     # 개별 주문 가능
    'DEFAULT': 1
}

def calculate_pipe_purchase_quantity(materials: List[Dict]) -> Dict:
    """
    PIPE 구매 수량 계산
    - 각 절단마다 3mm 손실
    - 6,000mm (6M) 단위로 올림
    """
    total_bom_length = 0
    cutting_count = 0
    pipe_details = []
    
    for material in materials:
        # 길이 정보 추출
        length_mm = float(material.get('length_mm', 0) or 0)
        if length_mm > 0:
            total_bom_length += length_mm
            cutting_count += 1
            pipe_details.append({
                'description': material.get('original_description', ''),
                'length_mm': length_mm,
                'quantity': material.get('quantity', 1)
            })
    
    # 절단 손실 계산 (각 절단마다 3mm)
    cutting_loss = cutting_count * 3
    
    # 총 필요 길이 = BOM 길이 + 절단 손실
    required_length = total_bom_length + cutting_loss
    
    # 6M 단위로 올림 계산
    standard_length = 6000  # 6M = 6,000mm
    pipes_needed = math.ceil(required_length / standard_length) if required_length > 0 else 0
    total_purchase_length = pipes_needed * standard_length
    waste_length = total_purchase_length - required_length if pipes_needed > 0 else 0
    
    return {
        'bom_quantity': total_bom_length,
        'cutting_count': cutting_count,
        'cutting_loss': cutting_loss,
        'required_length': required_length,
        'pipes_count': pipes_needed,
        'calculated_qty': total_purchase_length,
        'waste_length': waste_length,
        'utilization_rate': (required_length / total_purchase_length * 100) if total_purchase_length > 0 else 0,
        'unit': 'mm',
        'pipe_details': pipe_details
    }

def calculate_standard_purchase_quantity(category: str, bom_quantity: float, 
                                       safety_factor: float = None) -> Dict:
    """
    일반 자재 구매 수량 계산
    - 여유율 적용
    - 최소 주문 수량 적용
    """
    # 여유율 결정
    if safety_factor is None:
        safety_factor = SAFETY_FACTORS.get(category, SAFETY_FACTORS['DEFAULT'])
    
    # 1단계: 여유율 적용
    safety_qty = bom_quantity * safety_factor
    
    # 2단계: 최소 주문 수량 확인
    min_order_qty = MINIMUM_ORDER_QTY.get(category, MINIMUM_ORDER_QTY['DEFAULT'])
    
    # 3단계: 최소 주문 수량과 비교하여 큰 값 선택
    calculated_qty = max(safety_qty, min_order_qty)
    
    # 4단계: 특별 처리 (BOLT는 박스 단위로 올림)
    if category == 'BOLT' and calculated_qty > min_order_qty:
        calculated_qty = math.ceil(calculated_qty / min_order_qty) * min_order_qty
    
    return {
        'bom_quantity': bom_quantity,
        'safety_factor': safety_factor,
        'safety_qty': safety_qty,
        'min_order_qty': min_order_qty,
        'calculated_qty': calculated_qty,
        'waste_quantity': calculated_qty - bom_quantity,
        'utilization_rate': (bom_quantity / calculated_qty * 100) if calculated_qty > 0 else 0
    }

def generate_purchase_items_from_materials(db: Session, file_id: int, 
                                         job_no: str, revision: str) -> List[Dict]:
    """
    자재 데이터로부터 구매 품목 생성
    """
    # 1. 파일의 모든 자재 조회
    materials_query = text("""
        SELECT m.*, 
               pd.length_mm, pd.outer_diameter, pd.schedule, pd.material_spec as pipe_material_spec,
               fd.fitting_type, fd.connection_method as fitting_connection,
               vd.valve_type, vd.connection_method as valve_connection, vd.pressure_rating as valve_pressure,
               fl.flange_type, fl.pressure_rating as flange_pressure,
               gd.gasket_type, gd.material_type as gasket_material,
               bd.bolt_type, bd.material_standard, bd.diameter,
               id.instrument_type
        FROM materials m
        LEFT JOIN pipe_details pd ON m.id = pd.material_id
        LEFT JOIN fitting_details fd ON m.id = fd.material_id  
        LEFT JOIN valve_details vd ON m.id = vd.material_id
        LEFT JOIN flange_details fl ON m.id = fl.material_id
        LEFT JOIN gasket_details gd ON m.id = gd.material_id
        LEFT JOIN bolt_details bd ON m.id = bd.material_id
        LEFT JOIN instrument_details id ON m.id = id.material_id
        WHERE m.file_id = :file_id
        ORDER BY m.classified_category, m.original_description
    """)
    
    materials = db.execute(materials_query, {"file_id": file_id}).fetchall()
    
    # 2. 카테고리별로 그룹핑
    grouped_materials = {}
    for material in materials:
        category = material.classified_category or 'OTHER'
        if category not in grouped_materials:
            grouped_materials[category] = []
        grouped_materials[category].append(dict(material))
    
    # 3. 각 카테고리별로 구매 품목 생성
    purchase_items = []
    
    for category, category_materials in grouped_materials.items():
        if category == 'PIPE':
            # PIPE는 재질+사이즈+스케줄별로 그룹핑
            pipe_groups = {}
            for material in category_materials:
                # 그룹핑 키 생성
                material_spec = material.get('pipe_material_spec') or material.get('material_grade', '')
                outer_diameter = material.get('outer_diameter') or material.get('main_nom', '')
                schedule = material.get('schedule', '')
                
                group_key = f"{material_spec}|{outer_diameter}|{schedule}"
                
                if group_key not in pipe_groups:
                    pipe_groups[group_key] = []
                pipe_groups[group_key].append(material)
            
            # 각 PIPE 그룹별로 구매 수량 계산
            for group_key, group_materials in pipe_groups.items():
                pipe_calc = calculate_pipe_purchase_quantity(group_materials)
                
                if pipe_calc['calculated_qty'] > 0:
                    material_spec, outer_diameter, schedule = group_key.split('|')
                    
                    # 품목 코드 생성
                    item_code = generate_item_code('PIPE', material_spec, outer_diameter, schedule)
                    
                    # 사양 생성
                    spec_parts = [f"PIPE {outer_diameter}"]
                    if schedule: spec_parts.append(schedule)
                    if material_spec: spec_parts.append(material_spec)
                    specification = ', '.join(spec_parts)
                    
                    purchase_item = {
                        'item_code': item_code,
                        'category': 'PIPE',
                        'specification': specification,
                        'material_spec': material_spec,
                        'size_spec': outer_diameter,
                        'unit': 'mm',
                        **pipe_calc,
                        'job_no': job_no,
                        'revision': revision,
                        'file_id': file_id,
                        'materials': group_materials
                    }
                    purchase_items.append(purchase_item)
        
        else:
            # 기타 자재들은 사양별로 그룹핑
            spec_groups = generate_material_specs_for_category(category_materials, category)
            
            for spec_key, spec_data in spec_groups.items():
                if spec_data['totalQuantity'] > 0:
                    # 구매 수량 계산
                    calc_result = calculate_standard_purchase_quantity(
                        category, 
                        spec_data['totalQuantity']
                    )
                    
                    # 품목 코드 생성  
                    item_code = generate_item_code(category, spec_data.get('material_spec', ''), 
                                                 spec_data.get('size_display', ''))
                    
                    purchase_item = {
                        'item_code': item_code,
                        'category': category,
                        'specification': spec_data.get('full_spec', spec_key),
                        'material_spec': spec_data.get('material_spec', ''),
                        'size_spec': spec_data.get('size_display', ''),
                        'unit': spec_data.get('unit', 'EA'),
                        **calc_result,
                        'job_no': job_no,
                        'revision': revision,
                        'file_id': file_id,
                        'materials': spec_data['items']
                    }
                    purchase_items.append(purchase_item)
    
    return purchase_items

def generate_material_specs_for_category(materials: List[Dict], category: str) -> Dict:
    """카테고리별 자재 사양 그룹핑 (MaterialsPage.jsx 로직과 동일)"""
    specs = {}
    
    for material in materials:
        spec_key = ''
        spec_data = {}
        
        if category == 'FITTING':
            fitting_type = material.get('fitting_type', 'FITTING')
            connection_method = material.get('fitting_connection', '')
            material_spec = material.get('material_grade', '')
            main_nom = material.get('main_nom', '')
            red_nom = material.get('red_nom', '')
            size_display = f"{main_nom} x {red_nom}" if red_nom else main_nom
            
            spec_parts = [fitting_type]
            if connection_method: spec_parts.append(connection_method)
            full_spec = ', '.join(spec_parts)
            
            spec_key = f"FITTING|{full_spec}|{material_spec}|{size_display}"
            spec_data = {
                'category': 'FITTING',
                'full_spec': full_spec,
                'material_spec': material_spec,
                'size_display': size_display,
                'unit': 'EA'
            }
            
        elif category == 'VALVE':
            valve_type = material.get('valve_type', 'VALVE')
            connection_method = material.get('valve_connection', '')
            pressure_rating = material.get('valve_pressure', '')
            material_spec = material.get('material_grade', '')
            main_nom = material.get('main_nom', '')
            
            spec_parts = [valve_type.replace('_', ' ')]
            if connection_method: spec_parts.append(connection_method.replace('_', ' '))
            if pressure_rating: spec_parts.append(pressure_rating)
            full_spec = ', '.join(spec_parts)
            
            spec_key = f"VALVE|{full_spec}|{material_spec}|{main_nom}"
            spec_data = {
                'category': 'VALVE', 
                'full_spec': full_spec,
                'material_spec': material_spec,
                'size_display': main_nom,
                'unit': 'EA'
            }
            
        elif category == 'FLANGE':
            flange_type = material.get('flange_type', 'FLANGE')
            pressure_rating = material.get('flange_pressure', '')
            material_spec = material.get('material_grade', '')
            main_nom = material.get('main_nom', '')
            
            spec_parts = [flange_type]
            if pressure_rating: spec_parts.append(pressure_rating)
            full_spec = ', '.join(spec_parts)
            
            spec_key = f"FLANGE|{full_spec}|{material_spec}|{main_nom}"
            spec_data = {
                'category': 'FLANGE',
                'full_spec': full_spec, 
                'material_spec': material_spec,
                'size_display': main_nom,
                'unit': 'EA'
            }
            
        elif category == 'BOLT':
            bolt_type = material.get('bolt_type', 'BOLT')
            material_standard = material.get('material_standard', '')
            diameter = material.get('diameter', material.get('main_nom', ''))
            material_spec = material_standard or material.get('material_grade', '')
            
            spec_parts = [bolt_type.replace('_', ' ')]
            if material_standard: spec_parts.append(material_standard)
            full_spec = ', '.join(spec_parts)
            
            spec_key = f"BOLT|{full_spec}|{material_spec}|{diameter}"
            spec_data = {
                'category': 'BOLT',
                'full_spec': full_spec,
                'material_spec': material_spec,
                'size_display': diameter,
                'unit': 'EA'
            }
            
        elif category == 'GASKET':
            gasket_type = material.get('gasket_type', 'GASKET')
            gasket_material = material.get('gasket_material', '')
            material_spec = gasket_material or material.get('material_grade', '')
            main_nom = material.get('main_nom', '')
            
            spec_parts = [gasket_type]
            if gasket_material: spec_parts.append(gasket_material)
            full_spec = ', '.join(spec_parts)
            
            spec_key = f"GASKET|{full_spec}|{material_spec}|{main_nom}"
            spec_data = {
                'category': 'GASKET',
                'full_spec': full_spec,
                'material_spec': material_spec,
                'size_display': main_nom,
                'unit': 'EA'
            }
            
        elif category == 'INSTRUMENT':
            instrument_type = material.get('instrument_type', 'INSTRUMENT')
            material_spec = material.get('material_grade', '')
            main_nom = material.get('main_nom', '')
            
            full_spec = instrument_type.replace('_', ' ')
            
            spec_key = f"INSTRUMENT|{full_spec}|{material_spec}|{main_nom}"
            spec_data = {
                'category': 'INSTRUMENT',
                'full_spec': full_spec,
                'material_spec': material_spec, 
                'size_display': main_nom,
                'unit': 'EA'
            }
            
        else:
            # 기타 자재
            material_spec = material.get('material_grade', '')
            size_display = material.get('main_nom') or material.get('size_spec', '')
            
            spec_key = f"{category}|{material_spec}|{size_display}"
            spec_data = {
                'category': category,
                'full_spec': material_spec,
                'material_spec': material_spec,
                'size_display': size_display,
                'unit': 'EA'
            }
        
        # 스펙별 수량 집계
        if spec_key not in specs:
            specs[spec_key] = {
                **spec_data,
                'totalQuantity': 0,
                'count': 0,
                'items': []
            }
        
        specs[spec_key]['totalQuantity'] += material.get('quantity', 0)
        specs[spec_key]['count'] += 1
        specs[spec_key]['items'].append(material)
    
    return specs

def generate_item_code(category: str, material_spec: str = '', size_spec: str = '', 
                      schedule: str = '') -> str:
    """구매 품목 코드 생성"""
    import hashlib
    
    # 기본 접두사
    prefix = f"PI-{category}"
    
    # 재질 약어 생성
    material_abbr = ''
    if 'A106' in material_spec:
        material_abbr = 'A106'
    elif 'A333' in material_spec:
        material_abbr = 'A333'
    elif 'SS316' in material_spec or '316' in material_spec:
        material_abbr = 'SS316'
    elif 'A105' in material_spec:
        material_abbr = 'A105'
    elif material_spec:
        material_abbr = material_spec.replace(' ', '')[:6]
    
    # 사이즈 약어
    size_abbr = size_spec.replace('"', 'IN').replace(' ', '').replace('x', 'X')[:10]
    
    # 스케줄 (PIPE용)
    schedule_abbr = schedule.replace(' ', '')[:6]
    
    # 유니크 해시 생성 (중복 방지)
    unique_str = f"{category}|{material_spec}|{size_spec}|{schedule}"
    hash_suffix = hashlib.md5(unique_str.encode()).hexdigest()[:4].upper()
    
    # 최종 코드 조합
    code_parts = [prefix]
    if material_abbr: code_parts.append(material_abbr)
    if size_abbr: code_parts.append(size_abbr)
    if schedule_abbr: code_parts.append(schedule_abbr)
    code_parts.append(hash_suffix)
    
    return '-'.join(code_parts)

def save_purchase_items_to_db(db: Session, purchase_items: List[Dict]) -> List[int]:
    """구매 품목을 데이터베이스에 저장"""
    saved_ids = []
    
    for item in purchase_items:
        # 기존 품목 확인 (동일 사양이 있는지)
        existing_query = text("""
            SELECT id FROM purchase_items 
            WHERE job_no = :job_no AND revision = :revision AND item_code = :item_code
        """)
        existing = db.execute(existing_query, {
            'job_no': item['job_no'],
            'revision': item['revision'], 
            'item_code': item['item_code']
        }).fetchone()
        
        if existing:
            # 기존 품목 업데이트
            update_query = text("""
                UPDATE purchase_items SET
                    bom_quantity = :bom_quantity,
                    calculated_qty = :calculated_qty,
                    safety_factor = :safety_factor,
                    cutting_loss = :cutting_loss,
                    pipes_count = :pipes_count,
                    waste_length = :waste_length,
                    detailed_spec = :detailed_spec,
                    updated_at = CURRENT_TIMESTAMP
                WHERE id = :id
            """)
            db.execute(update_query, {
                'id': existing.id,
                'bom_quantity': item['bom_quantity'],
                'calculated_qty': item['calculated_qty'],
                'safety_factor': item.get('safety_factor', 1.0),
                'cutting_loss': item.get('cutting_loss', 0),
                'pipes_count': item.get('pipes_count'),
                'waste_length': item.get('waste_length'),
                'detailed_spec': item.get('detailed_spec', '{}')
            })
            saved_ids.append(existing.id)
        else:
            # 새 품목 생성
            insert_query = text("""
                INSERT INTO purchase_items (
                    item_code, category, specification, material_spec, size_spec, unit,
                    bom_quantity, safety_factor, minimum_order_qty, calculated_qty,
                    cutting_loss, standard_length, pipes_count, waste_length,
                    job_no, revision, file_id, is_active, created_by
                ) VALUES (
                    :item_code, :category, :specification, :material_spec, :size_spec, :unit,
                    :bom_quantity, :safety_factor, :minimum_order_qty, :calculated_qty,
                    :cutting_loss, :standard_length, :pipes_count, :waste_length,
                    :job_no, :revision, :file_id, :is_active, :created_by
                ) RETURNING id
            """)
            
            result = db.execute(insert_query, {
                'item_code': item['item_code'],
                'category': item['category'],
                'specification': item['specification'],
                'material_spec': item['material_spec'],
                'size_spec': item['size_spec'],
                'unit': item['unit'],
                'bom_quantity': item['bom_quantity'],
                'safety_factor': item.get('safety_factor', 1.0),
                'minimum_order_qty': item.get('min_order_qty', 0),
                'calculated_qty': item['calculated_qty'],
                'cutting_loss': item.get('cutting_loss', 0),
                'standard_length': item.get('standard_length', 6000 if item['category'] == 'PIPE' else None),
                'pipes_count': item.get('pipes_count'),
                'waste_length': item.get('waste_length'),
                'job_no': item['job_no'],
                'revision': item['revision'], 
                'file_id': item['file_id'],
                'is_active': True,
                'created_by': 'system'
            })
            
            result_row = result.fetchone()
            new_id = result_row[0] if result_row else None
            saved_ids.append(new_id)
            
            # 개별 자재와 구매 품목 연결
            for material in item['materials']:
                mapping_query = text("""
                    INSERT INTO material_purchase_mapping (material_id, purchase_item_id)
                    VALUES (:material_id, :purchase_item_id)
                    ON CONFLICT (material_id, purchase_item_id) DO NOTHING
                """)
                db.execute(mapping_query, {
                    'material_id': material['id'],
                    'purchase_item_id': new_id
                })
    
    db.commit()
    return saved_ids