<?php

namespace Tests\Unit;

use App\Support\AnswerSolutionStepMarkerInjector;
use PHPUnit\Framework\TestCase;

class AnswerSolutionStepMarkerInjectorTest extends TestCase
{
    public function test_inserts_chinese_step_labels_before_two_subquestions(): void
    {
        $raw = '(1)因为 $f(x)=x$，所以 $f\'(x)=1$。(2)故结论成立。';
        $out = AnswerSolutionStepMarkerInjector::enrichIfNeeded($raw, 'answer');
        $this->assertStringStartsWith('步骤一：', $out);
        $this->assertStringContainsString('步骤二：', $out);
    }

    public function test_skips_when_step_markers_already_present(): void
    {
        $raw = '步骤1：(1)略 (2)略';
        $out = AnswerSolutionStepMarkerInjector::enrichIfNeeded($raw, 'answer');
        $this->assertSame($raw, $out);
    }

    public function test_skips_single_subquestion(): void
    {
        $raw = '(1)唯一小问';
        $out = AnswerSolutionStepMarkerInjector::enrichIfNeeded($raw, 'answer');
        $this->assertSame($raw, $out);
    }

    public function test_skips_choice_type(): void
    {
        $raw = '(1)A (2)B';
        $out = AnswerSolutionStepMarkerInjector::enrichIfNeeded($raw, 'choice');
        $this->assertSame($raw, $out);
    }

    public function test_does_not_trigger_on_function_value_f1(): void
    {
        $raw = '故$f(1)=0$，且 $g(2)=1$。';
        $out = AnswerSolutionStepMarkerInjector::enrichIfNeeded($raw, 'answer');
        $this->assertSame($raw, $out);
    }

    public function test_ordered_chain_skips_later_paren_one_so_no_step_three(): void
    {
        $raw = '(1)求$m$。(1)继续第一问。(2)第二问收尾。';
        $out = AnswerSolutionStepMarkerInjector::enrichIfNeeded($raw, 'answer');
        $this->assertStringStartsWith('步骤一：', $out);
        $this->assertStringContainsString('步骤二：(2)', $out);
        $this->assertStringNotContainsString('步骤三：', $out);
    }

    public function test_subquestion_on_newline_after_first(): void
    {
        $raw = "(1)第一问。\n(2)第二问。";
        $out = AnswerSolutionStepMarkerInjector::enrichIfNeeded($raw, 'answer');
        $this->assertStringStartsWith('步骤一：', $out);
        $this->assertStringContainsString('步骤二：(2)', $out);
    }

    public function test_fullwidth_paren_arabic_subquestions_get_step_labels(): void
    {
        $raw = '（1）当$a=2$时求得集合。（2）若选择①，则取值范围为……';
        $out = AnswerSolutionStepMarkerInjector::enrichIfNeeded($raw, 'answer');
        $this->assertStringStartsWith('步骤一：', $out);
        $this->assertStringContainsString('步骤二：（2）', $out);
    }
}