# inventory-backend/app/api/v1/warehouse.py
from flask import Blueprint, request, jsonify
from flask_jwt_extended import jwt_required
from app.extensions import db
from app.models.system import SysWarehouseLocation
from app.utils.decorators import audit_log

warehouse_bp = Blueprint('warehouse', __name__, url_prefix='/api/v1/warehouse')


def build_tree(nodes, parent_id=None):
    """
    将平铺的数据构建为树形结构
    """
    tree = []
    for node in nodes:
        if node.parent_id == parent_id:
            children = build_tree(nodes, node.id)
            node_dict = node.to_dict()
            if children:
                # 子节点按 name 升序排序
                children_sorted = sorted(children, key=lambda x: x.get('name', ''))
                node_dict['children'] = children_sorted
            else:
                node_dict['children'] = []
            tree.append(node_dict)
    # 当前层级按 name 升序排序
    tree_sorted = sorted(tree, key=lambda x: x.get('name', ''))
    return tree_sorted


@warehouse_bp.route('/tree', methods=['GET'])
def get_tree():
    """
    获取库位树形结构
    """
    try:
        # 查询所有库位，按 name 升序排序
        all_locations = SysWarehouseLocation.query.order_by(SysWarehouseLocation.name.asc()).all()

        # 构建树形结构
        tree_data = build_tree(all_locations, parent_id=None)
        
        return jsonify({
            'code': 200,
            'msg': 'success',
            'data': tree_data
        })
    except Exception as e:
        return jsonify({
            'code': 500,
            'msg': str(e),
            'data': None
        }), 500


@warehouse_bp.route('', methods=['POST'])
@jwt_required()
@audit_log(
    module='库位管理',
    action='新增',
    get_target_name_fn=lambda: request.get_json().get('name') if request.get_json() else None
)
def create_location():
    """
    创建库位
    """
    try:
        data = request.get_json()
        name = data.get('name', '').strip()
        parent_id = data.get('parent_id')  # None 表示顶级
        is_enabled = data.get('is_enabled', True)
        
        if not name:
            return jsonify({'code': 400, 'msg': '库位名称不能为空', 'data': None})
        
        # 计算 level 和 full_path
        if parent_id is None:
            level = 0
            full_path = name
            parent_full_path = ''
        else:
            parent = SysWarehouseLocation.query.get(parent_id)
            if not parent:
                return jsonify({'code': 400, 'msg': '父级库位不存在', 'data': None})
            level = parent.level + 1
            parent_full_path = parent.full_path or ''
            full_path = f"{parent_full_path}/{name}" if parent_full_path else name
        
        location = SysWarehouseLocation(
            name=name,
            parent_id=parent_id,
            full_path=full_path,
            level=level,
            is_enabled=is_enabled
        )
        db.session.add(location)
        db.session.commit()
        
        return jsonify({
            'code': 200,
            'msg': '创建成功',
            'data': location.to_dict()
        })
    except Exception as e:
        db.session.rollback()
        return jsonify({
            'code': 500,
            'msg': str(e),
            'data': None
        }), 500


@warehouse_bp.route('/<int:location_id>', methods=['PUT'])
@jwt_required()
@audit_log(
    module='库位管理',
    action='修改',
    get_target_id_fn=lambda: request.view_args.get('location_id'),
    get_target_name_fn=lambda: request.get_json().get('name') if request.get_json() else None
)
def update_location(location_id):
    """
    更新库位
    """
    try:
        data = request.get_json()
        location = SysWarehouseLocation.query.get(location_id)
        
        if not location:
            return jsonify({'code': 404, 'msg': '库位不存在', 'data': None})
        
        # 更新名称
        if 'name' in data and data['name']:
            new_name = data['name'].strip()
            if new_name != location.name:
                # 需要更新 full_path
                parent = location.parent
                if parent:
                    location.full_path = f"{parent.full_path}/{new_name}" if parent.full_path else new_name
                else:
                    location.full_path = new_name
                location.name = new_name
        
        # 更新启用状态
        if 'is_enabled' in data:
            location.is_enabled = data['is_enabled']
        
        db.session.commit()
        
        return jsonify({
            'code': 200,
            'msg': '更新成功',
            'data': location.to_dict()
        })
    except Exception as e:
        db.session.rollback()
        return jsonify({
            'code': 500,
            'msg': str(e),
            'data': None
        }), 500


@warehouse_bp.route('/<int:location_id>', methods=['DELETE'])
@jwt_required()
@audit_log(
    module='库位管理',
    action='删除',
    get_target_id_fn=lambda: request.view_args.get('location_id')
)
def delete_location(location_id):
    """
    删除库位（级联删除子库位）
    """
    try:
        location = SysWarehouseLocation.query.get(location_id)

        if not location:
            return jsonify({'code': 404, 'msg': '库位不存在', 'data': None})

        # 在删除前提取属性，避免 commit 后访问已删除对象
        deleted_loc_name = location.name

        # 递归删除所有子库位
        def delete_recursive(loc):
            # 先删除所有子节点
            children = SysWarehouseLocation.query.filter_by(parent_id=loc.id).all()
            for child in children:
                delete_recursive(child)
            # 再删除自身
            db.session.delete(loc)

        delete_recursive(location)
        db.session.commit()

        return jsonify({
            'code': 200,
            'msg': '删除成功',
            'deleted_location': deleted_loc_name
        })
    except Exception as e:
        db.session.rollback()
        return jsonify({
            'code': 500,
            'msg': str(e),
            'data': None
        }), 500


@warehouse_bp.route('/batch', methods=['DELETE'])
@jwt_required()
@audit_log(
    module='库位管理',
    action='批量删除'
)
def batch_delete_locations():
    """
    批量删除库位
    """
    try:
        ids = request.get_json()
        if not ids or not isinstance(ids, list):
            return jsonify({'code': 400, 'msg': '请提供要删除的库位ID列表', 'data': None})

        deleted_count = 0
        deleted_names = []

        for loc_id in ids:
            location = SysWarehouseLocation.query.get(loc_id)
            if not location:
                continue

            # 在删除前提取属性
            deleted_names.append(location.name)

            # 递归删除
            def delete_recursive(loc):
                children = SysWarehouseLocation.query.filter_by(parent_id=loc.id).all()
                for child in children:
                    delete_recursive(child)
                db.session.delete(loc)

            delete_recursive(location)
            deleted_count += 1

        db.session.commit()

        return jsonify({
            'code': 200,
            'msg': f'删除成功，共删除 {deleted_count} 个库位',
            'data': {'deleted_count': deleted_count, 'deleted_names': deleted_names}
        })
    except Exception as e:
        db.session.rollback()
        return jsonify({
            'code': 500,
            'msg': str(e),
            'data': None
        }), 500


@warehouse_bp.route('/batch-generate', methods=['POST'])
@jwt_required()
@audit_log(
    module='库位管理',
    action='批量生成'
)
def batch_generate_locations():
    """
    规则化批量新增库位
    """
    MAX_TOTAL = 3000  # 单次最多生成数量限制
    try:
        data = request.get_json()
        parent_id = data.get('parent_id')
        rules = data.get('rules', [])

        if not rules:
            return jsonify({'code': 400, 'msg': '请提供生成规则', 'data': None})

        # 验证规则并计算总数
        total_count = 1
        for rule in rules:
            start = rule.get('start', 1)
            end = rule.get('end', 1)
            total_count *= max(0, end - start + 1)

        if total_count > MAX_TOTAL:
            return jsonify({'code': 400, 'msg': f'单次生成数量不能超过 {MAX_TOTAL} 个，当前计划生成 {total_count} 个', 'data': None})

        # 初始化父级列表
        if parent_id:
            parent = SysWarehouseLocation.query.get(parent_id)
            if not parent:
                return jsonify({'code': 404, 'msg': '父级库位不存在', 'data': None})
            current_parents = [parent_id]
        else:
            current_parents = [None]

        # 逐层处理规则
        generated_ids = []

        for rule in rules:
            prefix = rule.get('prefix', '')
            start = rule.get('start', 1)
            end = rule.get('end', 1)
            pad = rule.get('pad', 1)

            new_locations = []

            for parent_id in current_parents:
                # 1. 动态获取当前特定父节点的信息（严禁放循环外面共享！）
                if parent_id is None:
                    current_level = 0
                    current_parent_path = ''
                else:
                    p = SysWarehouseLocation.query.get(parent_id)
                    current_level = (p.level + 1) if p else 0
                    current_parent_path = p.full_path if p and p.full_path else ''

                # 2. 生成当前父节点下的专属子节点
                for num in range(start, end + 1):
                    name = f"{prefix}{str(num).zfill(pad)}"
                    # 路径由当前特定的 current_parent_path 决定
                    full_path = f"{current_parent_path}/{name}" if current_parent_path else name

                    location = SysWarehouseLocation(
                        name=name,
                        parent_id=parent_id,
                        full_path=full_path,
                        level=current_level,
                        is_enabled=True
                    )
                    db.session.add(location)
                    new_locations.append(location)

            # 单层循环结束后再 flush 和获取新 ID 列表
            db.session.flush()
            current_parents = [loc.id for loc in new_locations]
            generated_ids.extend(current_parents)

        db.session.commit()

        return jsonify({
            'code': 200,
            'msg': f'生成成功，共生成 {len(generated_ids)} 个库位',
            'data': {'generated_count': len(generated_ids), 'generated_ids': generated_ids}
        })
    except Exception as e:
        db.session.rollback()
        return jsonify({
            'code': 500,
            'msg': str(e),
            'data': None
        }), 500