import csv
from typing import List, Optional
from .student_dal import IStudentDAL
from ..model.student import Student
from datetime import datetime


class CsvStudentDAL(IStudentDAL):
    """学生信息的CSV文件存储实现"""

    def __init__(self, file_path: str = 'students.csv'):
        self.file_path = file_path
        self.headers = ['name', 'id_card', 'stu_id', 'gender', 'height', 'weight',
                        'enrollment_date', 'class_name', 'major', 'email', 'phone']

        # 确保文件存在
        self._ensure_file_exists()

    def _ensure_file_exists(self):
        """确保CSV文件存在并包含表头"""
        try:
            with open(self.file_path, 'r', encoding='utf-8') as file:
                reader = csv.reader(file)
                if not any(reader):  # 文件为空
                    self._write_headers()
        except FileNotFoundError:
            self._write_headers()

    def _write_headers(self):
        """写入CSV文件表头"""
        with open(self.file_path, 'w', encoding='utf-8', newline='') as file:
            writer = csv.DictWriter(file, fieldnames=self.headers)
            writer.writeheader()

    def _student_to_row(self, student: Student) -> dict:
        """将Student对象转换为CSV行数据"""
        return {
            'name': student.name,
            'id_card': student.id_card,
            'stu_id': student.stu_id,
            'gender': student.gender,
            'height': student.height,
            'weight': student.weight,
            'enrollment_date': str(student.enrollment_date) if student.enrollment_date else '',
            'class_name': student.class_name,
            'major': student.major,
            'email': student.email,
            'phone': student.phone
        }

    def _row_to_student(self, row: dict) -> Student:
        """将CSV行数据转换为Student对象"""
        # 处理日期类型，将字符串转换为datetime.date对象
        enrollment_date = row['enrollment_date']
        if enrollment_date:
            enrollment_date = datetime.strptime(enrollment_date, '%Y-%m-%d').date()

        # 处理布尔类型，将字符串转换为布尔值
        gender = row['gender']
        if gender:
            gender = gender.lower() == 'true'

        # 处理数值类型，将字符串转换为数值
        height = int(row['height']) if row['height'] else None
        weight = float(row['weight']) if row['weight'] else None
        # 创建并返回学生对象
        return Student(
            name=row['name'],
            id_card=row['id_card'],
            stu_id=row['stu_id'],
            gender=gender,
            height=height,
            weight=weight,
            enrollment_date=enrollment_date,
            class_name=row['class_name'],
            major=row['major'],
            email=row['email'],
            phone=row['phone']
        )

    def get_by_id(self, id_card: str) -> Optional[Student]:
        """根据身份证号获取学生信息"""
        with open(self.file_path, 'r', encoding='utf-8') as file:
            reader = csv.DictReader(file)
            for row in reader:
                if row['id_card'] == id_card:
                    return self._row_to_student(row)
        return None

    def get_by_stu_id(self, stu_id: str) -> Optional[Student]:
        """根据学号获取学生信息"""
        with open(self.file_path, 'r', encoding='utf-8') as file:
            reader = csv.DictReader(file)
            for row in reader:
                if row['stu_id'] == stu_id:
                    return self._row_to_student(row)
        return None

    def get_all(self) -> List[Student]:
        """获取所有学生信息"""
        students = []
        with open(self.file_path, 'r', encoding='utf-8') as file:
            reader = csv.DictReader(file)
            for row in reader:
                students.append(self._row_to_student(row))
        return students

    def add(self, student: Student) -> bool:
        """添加学生信息"""
        # 检查学号和身份证号是否已存在
        if self.get_by_id(student.id_card) or self.get_by_stu_id(student.stu_id):
            return False
        # 将学生信息追加到CSV文件
        with open(self.file_path, 'a', encoding='utf-8', newline='') as file:
            writer = csv.DictWriter(file, fieldnames=self.headers)
            writer.writerow(self._student_to_row(student))
        return True

    def update(self, student: Student) -> bool:
        """
        更新学生信息
        通过身份证号匹配要更新的记录
        """
        students = self.get_all() # 获取所有学生信息
        updated = False

        # 重写整个CSV文件，替换匹配的学生记录
        with open(self.file_path, 'w', encoding='utf-8', newline='') as file:
            writer = csv.DictWriter(file, fieldnames=self.headers)
            writer.writeheader()# 写入表头

            for s in students:
                if s.id_card == student.id_card:  # 找到匹配的学生记录
                    writer.writerow(self._student_to_row(student))
                    updated = True
                else:
                    writer.writerow(self._student_to_row(s)) # 保持原有记录不变

        return updated

    def delete_by_id(self, id_card: str) -> bool:
        """
        根据身份证号删除学生信息
        通过重写整个文件排除要删除的记录
        """
        students = self.get_all()  # 获取所有学生信息
        deleted = False

        # 重写整个CSV文件，排除要删除的学生记录
        with open(self.file_path, 'w', encoding='utf-8', newline='') as file:
            writer = csv.DictWriter(file, fieldnames=self.headers)
            writer.writeheader()  # 写入表头

            for s in students:
                if s.id_card == id_card:  # 找到匹配的学生记录
                    deleted = True  # 标记已删除
                else:
                    writer.writerow(self._student_to_row(s))  # 保留其他记录

        return deleted

    def delete_by_stu_id(self, stu_id: str) -> bool:
        """
        根据学号删除学生信息
        通过重写整个文件排除要删除的记录
        """
        students = self.get_all()  # 获取所有学生信息
        deleted = False

        # 重写整个CSV文件，排除要删除的学生记录
        with open(self.file_path, 'w', encoding='utf-8', newline='') as file:
            writer = csv.DictWriter(file, fieldnames=self.headers)
            writer.writeheader()  # 写入表头

            for s in students:
                if s.stu_id == stu_id:  # 找到匹配的学生记录
                    deleted = True  # 标记已删除
                else:
                    writer.writerow(self._student_to_row(s))  # 保留其他记录

        return deleted
    def search_by_name(self, name: str) -> List[Student]:
        """根据姓名模糊查询学生信息"""
        return [s for s in self.get_all() if name in s.name]

    def search_by_class(self, class_name: str) -> List[Student]:
        """根据班级模糊查询学生信息"""
        return [s for s in self.get_all() if class_name in (s.class_name or '')]

    def search_by_major(self, major: str) -> List[Student]:
        """根据专业模糊查询学生信息"""
        return [s for s in self.get_all() if major in (s.major or '')]