package main

import "testing"

// 还原自 .ass 的弹幕：原格式的弹道是按「只有内容」的宽度占位的，渲染用的是
// 「昵称(uid):内容 + 头像」的宽度，占位更长 → 同弹道会追尾。重排后必须分开。
func TestRelayoutSeparatesRestoredOverlap(t *testing.T) {
	meta := danmuMeta{PlayResX: 1920, PlayResY: 1080, FontSize: 60}
	content := "哈哈哈哈哈哈哈哈"
	// 两条原本同弹道、间隔 2.5 秒：按内容宽度（8×60=480）算，2.5 秒时前一条已经让位；
	// 按昵称头像宽度（头像48+间隔10+文本720）算，前一条要到约 2.9 秒才让位
	records := []danmuRecord{
		{Time: 0, UID: 101, Name: "甲", Content: content, Lane: 0, Width: 480},
		{Time: 2.5, UID: 202, Name: "乙", Content: content, Lane: 0, Width: 480},
	}

	relayoutLanes(records, meta)

	if records[0].Lane == records[1].Lane {
		t.Fatalf("两条追尾的弹幕重排后仍在同一条弹道 %d", records[0].Lane)
	}
	// 宽度也要按昵称头像版重算，否则滚动速度还是错的
	want := textWidth(speakerText("甲", 101, content), meta.FontSize)
	if records[0].Width != want {
		t.Errorf("宽度应重算为 %d，实际 %d", want, records[0].Width)
	}
}

// 录制时存下来的弹道本来就是按同一套公式算的，重排应当原样保留
func TestRelayoutKeepsLiveLayout(t *testing.T) {
	meta := danmuMeta{PlayResX: 1920, PlayResY: 1080, FontSize: 48}
	var records []danmuRecord
	for i := 0; i < 40; i++ {
		records = append(records, danmuRecord{
			Time: float64(i) * 0.4, UID: int64(100 + i), Name: "观众", Content: "测试弹幕内容",
		})
	}
	relayoutLanes(records, meta)
	first := make([]int, len(records))
	for i, r := range records {
		first[i] = r.Lane
	}

	relayoutLanes(records, meta)
	for i, r := range records {
		if r.Lane != first[i] {
			t.Fatalf("第 %d 条重排两次结果不一致：%d → %d", i, first[i], r.Lane)
		}
	}
}

// 输入顺序乱了也要按时间重排，否则弹道占用顺序错乱
func TestRelayoutSortsByTime(t *testing.T) {
	meta := danmuMeta{PlayResX: 1920, PlayResY: 1080, FontSize: 48}
	shuffled := []danmuRecord{
		{Time: 5, UID: 1, Name: "甲", Content: "第三条"},
		{Time: 1, UID: 2, Name: "乙", Content: "第一条"},
		{Time: 3, UID: 3, Name: "丙", Content: "第二条"},
	}
	sorted := []danmuRecord{
		{Time: 1, UID: 2, Name: "乙", Content: "第一条"},
		{Time: 3, UID: 3, Name: "丙", Content: "第二条"},
		{Time: 5, UID: 1, Name: "甲", Content: "第三条"},
	}
	relayoutLanes(shuffled, meta)
	relayoutLanes(sorted, meta)
	for i := range sorted {
		if shuffled[i].Lane != sorted[i].Lane {
			t.Errorf("第 %d 条弹道不一致：%d vs %d", i, shuffled[i].Lane, sorted[i].Lane)
		}
	}
}

// 字号越小，同一条弹幕在屏幕上停留时占用的时间越短，弹道占用也更宽松
func TestRelayoutWidthScalesWithFontSize(t *testing.T) {
	big := []danmuRecord{{Time: 0, UID: 7, Name: "甲", Content: "短弹幕"}}
	small := []danmuRecord{{Time: 0, UID: 7, Name: "甲", Content: "短弹幕"}}

	relayoutLanes(big, danmuMeta{PlayResX: 1920, PlayResY: 1080, FontSize: 60})
	relayoutLanes(small, danmuMeta{PlayResX: 1920, PlayResY: 1080, FontSize: 30})

	if big[0].Width <= small[0].Width {
		t.Errorf("字号 60 的宽度 %d 应大于字号 30 的 %d", big[0].Width, small[0].Width)
	}
	if big[0].Width != small[0].Width*2 {
		t.Errorf("宽度应随字号等比缩放：60 → %d，30 → %d", big[0].Width, small[0].Width)
	}
}

// 多分段（断流重连）拼接时，remapJsonlTimes 只改时间、保留各段自己算的弹道，
// 两段各自都从 0 号弹道开始排，时间压缩到同一条轴之后必然互相压。重排按拼接后
// 的时间轴统一分配，这种跨段冲突也会一并消掉。
func TestRelayoutFixesConcatenatedSegmentConflict(t *testing.T) {
	meta := danmuMeta{PlayResX: 1920, PlayResY: 1080, FontSize: 48}
	mk := func(base float64) []danmuRecord {
		var out []danmuRecord
		for i := 0; i < 12; i++ {
			out = append(out, danmuRecord{
				Time:    base + float64(i)*0.4,
				UID:     int64(3000 + i),
				Name:    "观众",
				Content: "断流前后各自的弹幕",
			})
		}
		return out
	}
	// 两段各自从 0 秒开始排（录制时就是这样），拼接后第二段紧接第一段
	first := mk(0)
	relayoutLanes(first, meta)
	second := mk(4.8)
	relayoutLanes(second, meta)
	records := append(append([]danmuRecord{}, first...), second...)

	// 前提：这种拼法本来就撞（第二段的 0 号弹道紧接第一段的 0 号弹道）
	if overlaps := countLaneOverlaps(records, meta); overlaps == 0 {
		t.Fatal("两段直接拼起来本应有同弹道冲突，用例前提不成立")
	}

	relayoutLanes(records, meta)

	if overlaps := countLaneOverlaps(records, meta); overlaps != 0 {
		t.Errorf("重排后仍有 %d 条同弹道冲突", overlaps)
	}
}

// 弹幕坐标系（PlayRes）和视频分辨率不一致时统一到视频坐标系：
// 跟随文件时字号按高度比换算，用户填了字号就按成片像素直接用
func TestUnifyDanmuSpace(t *testing.T) {
	cases := []struct {
		name                 string
		resX, resY, fontSize int
		vw, vh               int
		override             int
		wantChanged          bool
		wantFontSize         int
	}{
		{"坐标系一致不动", 1920, 1080, 60, 1920, 1080, 0, false, 60},
		{"960x540 弹幕配 720x1280 视频（跟随文件）", 960, 540, 30, 720, 1280, 0, true, 71},
		{"同上但用户填了 42", 960, 540, 30, 720, 1280, 42, true, 42},
		{"手机档 720x1280 弹幕配 540x960 视频", 720, 1280, 60, 540, 960, 0, true, 45},
		{"探测不到视频尺寸就不动", 960, 540, 30, 0, 0, 0, false, 30},
		{"相同宽高比但不同分辨率也要按视频走", 1280, 720, 40, 1920, 1080, 0, true, 60},
	}
	for _, c := range cases {
		meta := danmuMeta{PlayResX: c.resX, PlayResY: c.resY, FontSize: c.fontSize}
		changed := unifyDanmuSpace(&meta, c.vw, c.vh, c.override)
		if changed != c.wantChanged {
			t.Errorf("%s：changed 应为 %v，实际 %v", c.name, c.wantChanged, changed)
		}
		if meta.FontSize != c.wantFontSize {
			t.Errorf("%s：字号应为 %d，实际 %d", c.name, c.wantFontSize, meta.FontSize)
		}
		if changed {
			if meta.PlayResX != c.vw || meta.PlayResY != c.vh {
				t.Errorf("%s：PlayRes 应为 %dx%d，实际 %dx%d", c.name, c.vw, c.vh, meta.PlayResX, meta.PlayResY)
			}
			// 统一之后头像尺寸和文字都在视频坐标系里，必须能对上
			if avatarSize(meta.FontSize) <= 0 {
				t.Errorf("%s：头像直径算出来是 %d", c.name, avatarSize(meta.FontSize))
			}
		} else if meta.PlayResX != c.resX || meta.PlayResY != c.resY {
			t.Errorf("%s：不该改的时候改了 PlayRes", c.name)
		}
	}
}

// 按渲染时的公式统计同弹道追尾条数
func countLaneOverlaps(records []danmuRecord, meta danmuMeta) int {
	show := int64(danmuShowSeconds * 1e9)
	resX := int64(meta.PlayResX)
	last := map[int]int64{} // 弹道 → 上一条的让位时刻
	over := 0
	for _, r := range records {
		total := int64(avatarSize(meta.FontSize)+avatarGap(meta.FontSize)) + int64(r.Width)
		rel := int64(r.Time * 1e9)
		emerge := rel + total*show/(resX+total)
		if prev, ok := last[r.Lane]; ok && rel < prev {
			over++
		}
		last[r.Lane] = emerge
	}
	return over
}

// 密集弹幕（弹道信息全是坏的：lane 都是 0、width 都是 0）重排后不应再有追尾，
// 也不该超过弹道行数上限
func TestRelayoutNoOverlapOnDenseInput(t *testing.T) {
	meta := danmuMeta{PlayResX: 1920, PlayResY: 1080, FontSize: 60}
	texts := []string{"短", "中等长度的一条弹幕", "这是一条很长的弹幕内容用来占位置", "colong"}
	var records []danmuRecord
	t0 := 0.0
	for i := 0; i < 600; i++ {
		records = append(records, danmuRecord{
			Time:    t0,
			UID:     int64(1000 + i%7),
			Name:    "观众" + string(rune('A'+i%26)),
			Content: texts[i%len(texts)],
			Lane:    0,
			Width:   0,
		})
		t0 += 0.05 + float64(i%5)*0.07 // 0.05 ~ 0.33 秒一条
	}

	relayoutLanes(records, meta)

	show := int64(danmuShowSeconds * 1e9)
	resX := int64(meta.PlayResX)
	type state struct{ emerge int64 }
	last := map[int]state{}
	for i, r := range records {
		if r.Lane < 0 || r.Lane >= laneNum {
			t.Fatalf("第 %d 条弹道越界：%d", i, r.Lane)
		}
		total := int64(avatarSize(meta.FontSize)+avatarGap(meta.FontSize)) + int64(r.Width)
		if total <= 0 {
			t.Fatalf("第 %d 条宽度没算出来：%d", i, r.Width)
		}
		rel := int64(r.Time * 1e9)
		emerge := rel + total*show/(resX+total)
		if prev, ok := last[r.Lane]; ok && rel < prev.emerge {
			t.Fatalf("第 %d 条和上一条挤在同弹道 %d：出现 %v 早于上一条让位 %v", i, r.Lane, r.Time, float64(prev.emerge)/1e9)
		}
		last[r.Lane] = state{emerge}
	}
}