import os
import json
from datetime import date
from typing import List, Optional
from student.Student import Student


class StudentDAL:
    def __init__(self, file_path: str):
        self.file_path = file_path
        self._ensure_file_exists()

    def _ensure_file_exists(self):
        """确保文件存在"""
        if not os.path.exists(self.file_path):
            os.makedirs(os.path.dirname(self.file_path), exist_ok=True)
            with open(self.file_path, 'w', encoding='utf-8') as f:
                json.dump([], f)

    def _load_data(self) -> List[dict]:
        """加载数据"""
        try:
            with open(self.file_path, 'r', encoding='utf-8') as f:
                return json.load(f)
        except (FileNotFoundError, json.JSONDecodeError):
            return []

    def _save_data(self, data: List[dict]):
        """保存数据"""
        with open(self.file_path, 'w', encoding='utf-8') as f:
            json.dump(data, f, ensure_ascii=False, indent=4)

    def add_student(self, student: Student) -> bool:
        data = self._load_data()

        # 检查身份证号是否唯一
        if any(s['id_card'] == student.id_card for s in data):
            return False

        # 检查学号是否唯一
        if any(s['stu_id'] == student.stu_id for s in data):
            return False

        data.append(student.to_dict())
        self._save_data(data)
        return True

    def get_by_id_card(self, id_card: str) -> Optional[Student]:
        data = self._load_data()
        for student_dict in data:
            if student_dict['id_card'] == id_card:
                return Student.from_dict(student_dict)
        return None

    def get_by_stu_id(self, stu_id: str) -> Optional[Student]:
        data = self._load_data()
        for student_dict in data:
            if student_dict['stu_id'] == stu_id:
                return Student.from_dict(student_dict)
        return None

    def get_all(self) -> List[Student]:
        return [Student.from_dict(d) for d in self._load_data()]

    def update_student(self, stu_id: str, student: Student) -> bool:
        data = self._load_data()
        updated = False

        for i, student_dict in enumerate(data):
            if student_dict['stu_id'] == stu_id:
                # 保留原始身份证号
                new_data = student.to_dict()
                new_data['id_card'] = student_dict['id_card']
                data[i] = new_data
                updated = True
                break

        if updated:
            self._save_data(data)
        return updated

    def delete_student(self, stu_id: str) -> bool:
        data = self._load_data()
        original_count = len(data)
        data = [s for s in data if s['stu_id'] != stu_id]

        if len(data) < original_count:
            self._save_data(data)
            return True
        return False

    def search_by_name(self, name: str) -> List[Student]:
        data = self._load_data()
        name_lower = name.lower()
        return [
            Student.from_dict(d)
            for d in data
            if name_lower in d['name'].lower()
        ]

    def search_by_class(self, class_name: str) -> List[Student]:
        data = self._load_data()
        class_lower = class_name.lower()
        return [
            Student.from_dict(d)
            for d in data
            if d.get('class_name') and class_lower in d['class_name'].lower()
        ]

    def search_by_major(self, major: str) -> List[Student]:
        data = self._load_data()
        major_lower = major.lower()
        return [
            Student.from_dict(d)
            for d in data
            if d.get('major') and major_lower in d['major'].lower()
        ]

    def get_student_count(self) -> int:
        return len(self._load_data())

    def get_major_counts(self) -> dict:
        data = self._load_data()
        counts = {}
        for student_dict in data:
            major = student_dict.get('major', '未指定')
            counts[major] = counts.get(major, 0) + 1
        return counts

    def clear_all(self) -> bool:
        self._save_data([])
        return True

    def export_data(self, file_path: str) -> bool:
        data = self._load_data()
        try:
            with open(file_path, 'w', encoding='utf-8') as f:
                json.dump(data, f, ensure_ascii=False, indent=4)
            return True
        except Exception:
            return False

    def import_data(self, file_path: str) -> bool:
        try:
            with open(file_path, 'r', encoding='utf-8') as f:
                new_data = json.load(f)

            current_data = self._load_data()
            current_ids = {s['id_card'] for s in current_data}

            # 只导入不重复的学生
            to_import = [s for s in new_data if s['id_card'] not in current_ids]

            self._save_data(current_data + to_import)
            return True
        except Exception:
            return False