package main

import (
	"bytes"
	"errors"
	"flag"
	"io"
	"strings"
	"testing"
)

func TestRunArguments(t *testing.T) {
	var output bytes.Buffer
	err := run([]string{"-name", "小朱", "-minutes", "30"}, strings.NewReader(""), &output)
	if err != nil {
		t.Fatalf("运行失败：%v", err)
	}
	want := "学习者：小朱，学习时长：30 分钟\n"
	if output.String() != want {
		t.Errorf("输出=%q，期望=%q", output.String(), want)
	}
}

func TestRunInteractive(t *testing.T) {
	var output bytes.Buffer
	err := run([]string{"-interactive"}, strings.NewReader("小朱\n45\n"), &output)
	if err != nil {
		t.Fatalf("交互失败：%v", err)
	}
	want := "请输入姓名：请输入学习分钟数：学习者：小朱，学习时长：45 分钟\n"
	if output.String() != want {
		t.Errorf("输出=%q，期望=%q", output.String(), want)
	}
}

func TestRunErrors(t *testing.T) {
	tests := []struct {
		name  string
		args  []string
		input string
	}{
		{name: "missing_name", args: []string{"-minutes", "30"}},
		{name: "empty_name", args: []string{"-name", "  ", "-minutes", "30"}},
		{name: "zero", args: []string{"-name", "小朱", "-minutes", "0"}},
		{name: "too_large", args: []string{"-name", "小朱", "-minutes", "1441"}},
		{name: "invalid_flag", args: []string{"-unknown"}},
		{name: "invalid_number", args: []string{"-name", "小朱", "-minutes", "abc"}},
		{name: "positional", args: []string{"extra"}},
		{name: "mixed", args: []string{"-interactive", "-minutes", "0"}},
		{name: "missing_input", args: []string{"-interactive"}, input: "小朱\n"},
		{name: "invalid_input", args: []string{"-interactive"}, input: "小朱\nabc\n"},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			if err := run(tt.args, strings.NewReader(tt.input), io.Discard); err == nil {
				t.Fatal("预期返回错误，实际没有错误")
			}
		})
	}
}

func TestRunBounds(t *testing.T) {
	for _, minutes := range []string{"1", "1440"} {
		t.Run(minutes, func(t *testing.T) {
			err := run([]string{"-name", "小朱", "-minutes", minutes}, strings.NewReader(""), io.Discard)
			if err != nil {
				t.Fatalf("边界值应当有效：%v", err)
			}
		})
	}
}

func TestRunHelp(t *testing.T) {
	var output bytes.Buffer
	err := run([]string{"-h"}, strings.NewReader(""), &output)
	if !errors.Is(err, flag.ErrHelp) {
		t.Fatalf("期望帮助标记，实际错误：%v", err)
	}
	if !strings.Contains(output.String(), "-interactive") {
		t.Errorf("帮助信息未包含参数说明：%q", output.String())
	}
}