// Copyright 2026 tamakyi. All rights reserved.
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file.

package db

import (
	"context"
	"testing"
	"time"

	"github.com/stretchr/testify/require"
)

// TestBoxTrendAnswerByAnsweredDate 验证「每日回答数」按 answered_at 分组，
// 而不是按 created_at。
//
// 背景：BoxTrend 一度两条 SQL 都复用 created_at 的日期表达式，导致「40 天前创建、
// 昨天才回答」的提问被排除在窗口外（created_at < from），昨天/今天的回答数里
// 根本不出现；「今天创建、明天回答」的又会被记到今天。本测试构造一条
// 「创建日远早于窗口、回答日落在窗口内」的提问，断言它出现在回答日那天。
func TestBoxTrendAnswerByAnsweredDate(t *testing.T) {
	db, cleanup := newTestDB(t)
	ctx := context.Background()
	store := NewBoxAnalyticsStore(db)

	t.Cleanup(func() {
		_ = cleanup("questions")
	})

	now := time.Now()
	// 窗口 = 最近 7 天
	from := now.AddDate(0, 0, -6)
	to := now

	// 一条 40 天前创建、昨天才回答的提问
	answeredAt := now.AddDate(0, 0, -1)
	createdAt := now.AddDate(0, 0, -40)
	q := &Question{
		UserID:     9,
		Content:    "很久以前问的，昨天才回答",
		Answer:     "这是回答",
		AnsweredAt: &answeredAt,
	}
	// 直接写 created_at / answered_at，绕过 Create 的自动时间戳
	require.NoError(t, db.Model(&Question{}).Create(q).Error)
	require.NoError(t, db.Model(&Question{}).Where("id = ?", q.ID).
		Updates(map[string]interface{}{
			"created_at":  createdAt,
			"answered_at": answeredAt,
			"updated_at":  answeredAt,
		}).Error)

	trend, err := store.BoxTrend(ctx, 9, from, to)
	require.NoError(t, err)

	// 找到回答日那天（昨天）的计数，答案数应 >= 1
	var found bool
	for _, d := range trend {
		if d.Day.Year() == answeredAt.Year() &&
			d.Day.Month() == answeredAt.Month() &&
			d.Day.Day() == answeredAt.Day() {
			require.GreaterOrEqual(t, d.Answers, int64(1),
				"回答应计入 answered_at 那一天，而不是按 created_at 被排除")
			found = true
		}
		// 创建日（40 天前）不应出现在窗口内
		if d.Day.Year() == createdAt.Year() &&
			d.Day.Month() == createdAt.Month() &&
			d.Day.Day() == createdAt.Day() {
			t.Errorf("创建日在窗口外，不应出现在趋势里")
		}
	}
	require.True(t, found, "回答日应出现在趋势结果里")
}