const AdminService = require('../services/adminService');
const { success, error } = require('../utils/response');

class AdminController {
    static async getStats(req, res) {
        try {
            const stats = await AdminService.getStats();
            success(res, stats, '获取统计信息成功');
        } catch (err) {
            console.error('Get Stats Error:', err);
            error(res, '服务器错误');
        }
    }

    static async getUsers(req, res) {
        try {
            const result = await AdminService.getUsers(req.query);
            res.json({
                success: true,
                message: '获取成功',
                data: result.data,
                pagination: result.pagination
            });
        } catch (err) {
            console.error('Get Users Error:', err);
            error(res, '服务器错误');
        }
    }

    static async createUser(req, res) {
        try {
            const { id, name, password, role } = req.body;
            
            if (!id || !name || !password || !role) {
                return error(res, '请填写所有必填字段', 400);
            }

            await AdminService.createUser(req.body, {
                user_id: req.session.user.id,
                ip: req.ip
            });
            success(res, null, '创建用户成功');
        } catch (err) {
            if (err.message === '用户ID已存在') {
                return error(res, err.message, 400);
            }
            console.error('Create User Error:', err);
            error(res, '服务器错误');
        }
    }

    static async updateUser(req, res) {
        try {
            const { id } = req.params;
            const updateData = req.body;
            
            await AdminService.updateUser(id, updateData, {
                user_id: req.session.user.id,
                ip: req.ip
            });
            success(res, null, '更新用户成功');
        } catch (err) {
            console.error('Update User Error:', err);
            error(res, '服务器错误');
        }
    }

    static async deleteUser(req, res) {
        try {
            const { id } = req.params;
            await AdminService.deleteUser(id, {
                user_id: req.session.user.id,
                ip: req.ip
            });
            success(res, null, '删除用户成功');
        } catch (err) {
            console.error('Delete User Error:', err);
            error(res, '服务器错误');
        }
    }

    // Student Management
    static async getStudents(req, res) {
        try {
            const result = await AdminService.getStudents(req.query);
            res.json({
                success: true,
                message: '获取学生列表成功',
                data: result.data,
                pagination: result.pagination
            });
        } catch (err) {
            console.error(err);
            error(res, '服务器错误');
        }
    }

    static async createStudent(req, res) {
        try {
            if (!req.body.id || !req.body.name) return error(res, 'ID和姓名必填', 400);
            await AdminService.createStudent(req.body, {
                user_id: req.session.user.id,
                ip: req.ip
            });
            success(res, null, '创建学生成功');
        } catch (err) {
            console.error(err);
            error(res, err.message || '创建失败', 400);
        }
    }

    static async updateStudent(req, res) {
        try {
            await AdminService.updateStudent(req.params.id, req.body, {
                user_id: req.session.user.id,
                ip: req.ip
            });
            success(res, null, '更新学生成功');
        } catch (err) {
            console.error(err);
            error(res, '更新失败');
        }
    }

    static async deleteStudent(req, res) {
        try {
            await AdminService.deleteStudent(req.params.id, {
                user_id: req.session.user.id,
                ip: req.ip
            });
            success(res, null, '删除学生成功');
        } catch (err) {
            console.error(err);
            error(res, '删除失败');
        }
    }

    // Teacher Management
    static async getTeachers(req, res) {
        try {
            const result = await AdminService.getTeachers(req.query);
            res.json({
                success: true,
                message: '获取教师列表成功',
                data: result.data,
                pagination: result.pagination
            });
        } catch (err) {
            console.error(err);
            error(res, '服务器错误');
        }
    }

    static async createTeacher(req, res) {
        try {
            if (!req.body.id || !req.body.name) return error(res, '工号和姓名必填', 400);
            await AdminService.createTeacher(req.body, {
                user_id: req.session.user.id,
                ip: req.ip
            });
            success(res, null, '创建教师成功');
        } catch (err) {
            console.error(err);
            error(res, err.message || '创建失败', 400);
        }
    }

    static async updateTeacher(req, res) {
        try {
            await AdminService.updateTeacher(req.params.id, req.body, {
                user_id: req.session.user.id,
                ip: req.ip
            });
            success(res, null, '更新教师成功');
        } catch (err) {
            console.error(err);
            error(res, '更新失败');
        }
    }

    static async deleteTeacher(req, res) {
        try {
            await AdminService.deleteTeacher(req.params.id, {
                user_id: req.session.user.id,
                ip: req.ip
            });
            success(res, null, '删除教师成功');
        } catch (err) {
            console.error(err);
            error(res, '删除失败');
        }
    }

    // Grade Statistics
    static async getGradeStats(req, res) {
        try {
            const stats = await AdminService.getGradeStats();
            success(res, stats, '获取成绩统计成功');
        } catch (err) {
            console.error(err);
            error(res, '服务器错误');
        }
    }

    // System Settings
    static async getSettings(req, res) {
        try {
            const settings = await AdminService.getSettings();
            success(res, settings);
        } catch (err) {
            console.error(err);
            error(res, '服务器错误');
        }
    }

    static async saveSettings(req, res) {
        try {
            await AdminService.saveSettings(req.body, {
                user_id: req.session.user.id,
                ip: req.ip
            });
            success(res, null, '保存设置成功');
        } catch (err) {
            console.error(err);
            error(res, '保存失败');
        }
    }

    // Data Maintenance
    static async backupDatabase(req, res) {
        try {
            const result = await AdminService.backupDatabase({
                user_id: req.session.user.id,
                ip: req.ip
            });
            success(res, result, '数据库备份成功');
        } catch (err) {
            console.error(err);
            error(res, '备份失败');
        }
    }

    static async clearCache(req, res) {
        try {
            await AdminService.clearCache({
                user_id: req.session.user.id,
                ip: req.ip
            });
            success(res, null, '缓存已清理');
        } catch (err) {
            console.error(err);
            error(res, '清理失败');
        }
    }

    static async resetStudentPasswords(req, res) {
        try {
            await AdminService.resetStudentPasswords({
                user_id: req.session.user.id,
                ip: req.ip
            });
            success(res, null, '所有学生密码已重置为 123456');
        } catch (err) {
            console.error(err);
            error(res, '重置失败');
        }
    }

    // Operation Logs
    static async getOperationLogs(req, res) {
        try {
            const logs = await AdminService.getLogs(req.query);
            success(res, logs);
        } catch (err) {
            console.error(err);
            error(res, '获取日志失败');
        }
    }

    // Data Export
    static async exportStudents(req, res) {
        try {
            const data = await AdminService.exportStudents();
            const csv = jsonToCsv(data, ['id', 'name', 'class', 'major', 'grade', 'contact_info']);
            res.setHeader('Content-Type', 'text/csv; charset=utf-8');
            res.setHeader('Content-Disposition', 'attachment; filename=students.csv');
            res.send(csv);
        } catch (err) {
            console.error(err);
            error(res, '导出失败');
        }
    }

    static async exportTeachers(req, res) {
        try {
            const data = await AdminService.exportTeachers();
            const csv = jsonToCsv(data, ['id', 'name', 'department', 'title', 'contact_info', 'created_at']);
            res.setHeader('Content-Type', 'text/csv; charset=utf-8');
            res.setHeader('Content-Disposition', 'attachment; filename=teachers.csv');
            res.send(csv);
        } catch (err) {
            console.error(err);
            error(res, '导出失败');
        }
    }

    static async exportGrades(req, res) {
        try {
            const data = await AdminService.exportGrades();
            const csv = jsonToCsv(data, ['student_id', 'student_name', 'course_code', 'course_name', 'total_score', 'grade_point', 'grade_level', 'teacher_name']);
            res.setHeader('Content-Type', 'text/csv; charset=utf-8');
            res.setHeader('Content-Disposition', 'attachment; filename=grades.csv');
            res.send(csv);
        } catch (err) {
            console.error(err);
            error(res, '导出失败');
        }
    }
}

// Helper function
function jsonToCsv(data, fields) {
    if (!data || data.length === 0) return '';
    const header = fields.join(',') + '\n';
    const rows = data.map(row => {
        return fields.map(field => {
            const val = row[field] === null || row[field] === undefined ? '' : row[field];
            return `"${String(val).replace(/"/g, '""')}"`;
        }).join(',');
    }).join('\n');
    return '\ufeff' + header + rows; // Add BOM for Excel compatibility
}

module.exports = AdminController;