import json
import os
import csv
from datetime import date
from typing import List, Optional
from model.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):
        if not os.path.exists(self.file_path):
            with open(self.file_path, mode='w', encoding='utf-8') as file:
                json.dump([], file)

    def save_students(self, students: List[Student]) -> None:
        student_dicts = [student.to_dict() for student in students]
        with open(self.file_path, mode='w', encoding='utf-8') as file:
            json.dump(student_dicts, file, ensure_ascii=False, indent=4)

    def load_students(self) -> List[Student]:
        with open(self.file_path, mode='r', encoding='utf-8') as file:
            student_dicts = json.load(file)
            return [Student.from_dict(student_dict) for student_dict in student_dicts]

    def add_student(self, student: Student) -> bool:
        students = self.load_students()
        for existing_student in students:
            if existing_student.sid == student.sid:
                return False
        students.append(student)
        self.save_students(students)
        return True

    def find_student_by_sid(self, sid: str) -> Optional[Student]:
        students = self.load_students()
        for student in students:
            if student.sid == sid:
                return student
        return None

    def find_student_by_id_number(self, id_number: str) -> Optional[Student]:
        students = self.load_students()
        for student in students:
            if student.id_number == id_number:
                return student
        return None

    def find_students_by_name(self, name: str) -> List[Student]:
        students = self.load_students()
        return [student for student in students if name.lower() in student.name.lower()]

    def find_students_by_class_name(self, class_name: str) -> List[Student]:
        students = self.load_students()
        return [student for student in students if class_name.lower() in student.class_name.lower()]

    def find_students_by_major(self, major: str) -> List[Student]:
        students = self.load_students()
        return [student for student in students if major.lower() in student.major.lower()]

    def get_all_students(self) -> List[Student]:
        return self.load_students()

    def update_student(self, sid: str, updated_student: Student) -> bool:
        students = self.load_students()
        for i, student in enumerate(students):
            if student.sid == sid:
                students[i] = updated_student
                self.save_students(students)
                return True
        return False

    def update_student_partial(self, sid: str, name: Optional[str] = None, height: Optional[int] = None,
                               birth_date: Optional[date] = None, enrollment_date: Optional[date] = None,
                               class_name: Optional[str] = None, major: Optional[str] = None,
                               phone: Optional[str] = None, email: Optional[str] = None) -> bool:
        students = self.load_students()
        for i, student in enumerate(students):
            if student.sid == sid:
                if name is not None:
                    students[i].name = name
                if height is not None:
                    students[i].height = height
                if birth_date is not None:
                    students[i].birth_date = birth_date
                if enrollment_date is not None:
                    students[i].enrollment_date = enrollment_date
                if class_name is not None:
                    students[i].class_name = class_name
                if major is not None:
                    students[i].major = major
                if phone is not None:
                    students[i].phone = phone
                if email is not None:
                    students[i].email = email
                self.save_students(students)
                return True
        return False

    def delete_student(self, sid: str) -> bool:
        students = self.load_students()
        initial_length = len(students)
        students = [student for student in students if student.sid != sid]
        if len(students) < initial_length:
            self.save_students(students)
            return True
        return False

    def delete_student_by_id_number(self, id_number: str) -> bool:
        students = self.load_students()
        initial_length = len(students)
        students = [student for student in students if student.id_number != id_number]
        if len(students) < initial_length:
            self.save_students(students)
            return True
        return False

    def clear_all_students(self) -> None:
        self.save_students([])

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

    def check_student_exists(self, sid: str) -> bool:
        return self.find_student_by_sid(sid) is not None

    def export_to_json(self, file_path):
        students = self.load_students()
        student_dicts = [student.to_dict() for student in students]
        with open(file_path, mode='w', encoding='utf-8') as file:
            json.dump(student_dicts, file, ensure_ascii=False, indent=4)

    def import_from_json(self, file_path):
        try:
            with open(file_path, mode='r', encoding='utf-8') as file:
                student_dicts = json.load(file)
                students = [Student.from_dict(student_dict) for student_dict in student_dicts]
                self.save_students(students)
        except FileNotFoundError:
            print(f"文件 {file_path} 未找到。")
        except json.JSONDecodeError:
            print(f"文件 {file_path} 不是有效的 JSON 文件。")
        except ValueError as e:
            print(f"数据转换错误: {e}")

    def export_to_csv(self, file_path):
        students = self.load_students()
        if not students:
            print("没有数据可导出")
            return
        try:
            with open(file_path, 'w', encoding='utf-8-sig', newline='') as f:
                writer = csv.DictWriter(
                    f,
                    fieldnames=[
                        'sid', 'name', 'gender', 'height', 'weight', 'birth_date', 'enrollment_date',
                        'class_name', 'id_number', 'phone', 'email', 'major'
                    ]
                )
                writer.writeheader()
                for student in students:
                    data = student.to_dict()
                    # 将日期对象转换为字符串
                    data['birth_date'] = data['birth_date'].isoformat()
                    data['enrollment_date'] = data['enrollment_date'].isoformat()
                    writer.writerow(data)
            print(f"数据已导出到 {file_path}")
        except Exception as e:
            print(f"导出失败: {e}")

    def import_from_csv(self, file_path):
        try:
            students = []
            with open(file_path, mode='r', encoding='utf-8') as file:
                reader = csv.DictReader(file)
                for row in reader:
                    row['birth_date'] = date.fromisoformat(row['birth_date'])
                    row['enrollment_date'] = date.fromisoformat(row['enrollment_date'])
                    student = Student.from_dict(row)
                    students.append(student)
            self.save_students(students)
        except FileNotFoundError:
            print(f"文件 {file_path} 未找到。")
        except ValueError as e:
            print(f"日期格式错误: {e}")

    def get_average_height(self):
        students = self.load_students()
        if not students:
            return 0
        total_height = sum([student.height for student in students])
        return total_height / len(students)

    def count_students_by_height_range(self, min_height: int, max_height: int):
        students = self.load_students()
        return len([student for student in students if min_height <= student.height <= max_height])

    def count_students_by_enrollment_year(self, year: int):
        students = self.load_students()
        return len([student for student in students if student.enrollment_date.year == year])

    def count_students_by_age_range(self, min_age: int, max_age: int):
        today = date.today()
        students = self.load_students()
        return len([student for student in students if min_age <= today.year - student.birth_date.year <= max_age])

    def backup_data(self, backup_path):
        try:
            with open(self.file_path, mode='r', encoding='utf-8') as src_file, \
                    open(backup_path, mode='w', encoding='utf-8') as dst_file:
                dst_file.write(src_file.read())
            print(f"数据备份到 {backup_path} 成功。")
        except Exception as e:
            print(f"数据备份失败: {e}")

    def restore_data(self, backup_path):
        try:
            with open(backup_path, mode='r', encoding='utf-8') as src_file, \
                    open(self.file_path, mode='w', encoding='utf-8') as dst_file:
                dst_file.write(src_file.read())
            print(f"数据从 {backup_path} 恢复成功。")
        except FileNotFoundError:
            print(f"备份文件 {backup_path} 未找到。")
        except Exception as e:
            print(f"数据恢复失败: {e}")

    def count_students_by_major(self):
        """统计各专业学生人数"""
        students = self.load_students()
        major_count = {}
        for student in students:
            major = student.major
            if major in major_count:
                major_count[major] += 1
            else:
                major_count[major] = 1
        return major_count

    def calculate_average_height_weight(self, group_by='major'):
        """计算平均身高/体重（按班级或专业）"""
        students = self.load_students()
        group_info = {}
        for student in students:
            group_key = getattr(student, group_by)
            if group_key not in group_info:
                group_info[group_key] = {'height_sum': 0, 'weight_sum': 0, 'count': 0}
            group_info[group_key]['height_sum'] += student.height
            group_info[group_key]['weight_sum'] += student.weight
            group_info[group_key]['count'] += 1

        result = {}
        for group, info in group_info.items():
            average_height = info['height_sum'] / info['count']
            average_weight = info['weight_sum'] / info['count']
            result[group] = {'average_height': average_height, 'average_weight': average_weight}
        return result

    def calculate_gender_ratio(self):
        """统计性别比例"""
        students = self.load_students()
        male_count = 0
        female_count = 0
        for student in students:
            if student.gender == '男':
                male_count += 1
            elif student.gender == '女':
                female_count += 1
        total_count = male_count + female_count
        if total_count == 0:
            return {'male_ratio': 0, 'female_ratio': 0}
        male_ratio = male_count / total_count
        female_ratio = female_count / total_count
        return {'male_ratio': male_ratio, 'female_ratio': female_ratio}