<?php

namespace Tests\Unit;

use App\Services\StudentIdService;
use PHPUnit\Framework\TestCase;

class StudentIdServiceTest extends TestCase
{
    /**
     * 测试学生ID生成功能
     */
    public function test_generate_student_id(): void
    {
        $studentId = StudentIdService::generateStudentId();

        // 验证格式
        $this->assertTrue(StudentIdService::validateStudentIdFormat($studentId));

        // 验证格式模式
        $this->assertMatchesRegularExpression('/^stu_\d+_\d+$/', $studentId);

        // 验证组成部分
        $parts = explode('_', $studentId);
        $this->assertEquals('stu', $parts[0]);
        $this->assertIsNumeric($parts[1]); // 时间戳
        $this->assertIsNumeric($parts[2]); // 序号
    }

    /**
     * 测试生成多个学生ID的唯一性
     */
    public function test_generate_multiple_student_ids(): void
    {
        $ids = [];
        $count = 10;

        for ($i = 0; $i < $count; $i++) {
            $id = StudentIdService::generateStudentId();
            $this->assertTrue(StudentIdService::validateStudentIdFormat($id));
            $this->assertNotContains($id, $ids); // 确保唯一性
            $ids[] = $id;
        }

        $this->assertCount($count, $ids);
        $this->assertEquals(count($ids), count(array_unique($ids)));
    }

    /**
     * 测试学生ID格式验证功能
     */
    public function test_validate_student_id_format(): void
    {
        // 有效的格式
        $validIds = [
            'stu_1234567890_0',
            'stu_1609459200_1',
            'stu_9999999999_999',
        ];

        foreach ($validIds as $id) {
            $this->assertTrue(StudentIdService::validateStudentIdFormat($id), "ID {$id} 应该是有效的");
        }

        // 无效的格式
        $invalidIds = [
            'stu_abc_0',           // 非数字时间戳
            'stu_1234567890',      // 缺少序号
            'stu_1234567890_abc',  // 非数字序号
            'teacher_123_0',       // 错误前缀
            '1234567890_0',        // 缺少前缀
            '',                    // 空字符串
            'stu_',               // 缺少时间戳和序号
            'stu__0',             // 缺少时间戳
        ];

        foreach ($invalidIds as $id) {
            $this->assertFalse(StudentIdService::validateStudentIdFormat($id), "ID {$id} 应该是无效的");
        }
    }

    /**
     * 测试边界情况
     */
    public function test_edge_cases(): void
    {
        // 测试生成ID的时间戳部分是否在合理范围内
        $id = StudentIdService::generateStudentId();
        $parts = explode('_', $id);
        $timestamp = (int)$parts[1];

        // 验证时间戳是否在最近10年内（合理性检查）
        $tenYearsAgo = time() - (10 * 365 * 24 * 60 * 60);
        $tenYearsLater = time() + (10 * 365 * 24 * 60 * 60);

        $this->assertGreaterThanOrEqual($tenYearsAgo, $timestamp);
        $this->assertLessThanOrEqual($tenYearsLater, $timestamp);

        // 验证序号是非负整数
        $sequence = (int)$parts[2];
        $this->assertGreaterThanOrEqual(0, $sequence);
    }
}