package chunk

import (
	"testing"

	"mc/internal/block"
)

// TestIndex 验证一维索引换算。
func TestIndex(t *testing.T) {
	c := New(0, 0)
	if got := Index(0, 0, 0); got != 0 {
		t.Fatalf("Index(0,0,0) = %d", got)
	}
	if got := Index(1, 0, 0); got != 1 {
		t.Fatalf("Index(1,0,0) = %d", got)
	}
	if got := Index(0, 0, 1); got != 16 {
		t.Fatalf("Index(0,0,1) = %d", got)
	}
	if got := Index(0, 1, 0); got != 256 {
		t.Fatalf("Index(0,1,0) = %d", got)
	}
	_ = c
}

// TestSetGet 验证读写与脏标记。
func TestSetGet(t *testing.T) {
	c := New(3, -7)
	s := block.NewState(5, 0)
	c.SetBlock(2, 64, 3, s)
	if got := c.Block(2, 64, 3); got != s {
		t.Fatalf("读回 %v，期望 %v", got, s)
	}
	if !c.Dirty.Load() || !c.SaveDirty.Load() {
		t.Fatal("SetBlock 应标记 dirty/saveDirty")
	}
}

// TestNibble 验证 4-bit 光照打包（每字节 2 方块）。
func TestNibble(t *testing.T) {
	c := New(0, 0)
	// 相邻两个方块：一个偶数索引一个奇数索引，共用一个字节
	c.SetSkyLight(0, 10, 0, 15)
	c.SetSkyLight(1, 10, 0, 7)
	if got := c.SkyLight(0, 10, 0); got != 15 {
		t.Fatalf("sky(0) = %d，期望 15", got)
	}
	if got := c.SkyLight(1, 10, 0); got != 7 {
		t.Fatalf("sky(1) = %d，期望 7", got)
	}
	// 未设置的保持 0
	if got := c.BlockLight(0, 10, 0); got != 0 {
		t.Fatalf("blockLight(0) = %d，期望 0", got)
	}
}