package inventory

import (
	"path/filepath"
	"testing"

	"mc/internal/item"
)

// loadItemReg 加载物品注册表。
func loadItemReg(t *testing.T) *item.Registry {
	t.Helper()
	r, err := item.Load(filepath.Join("..", "..", "assets", "config", "items.json"))
	if err != nil {
		t.Fatalf("加载物品注册表失败: %v", err)
	}
	return r
}

// TestMerge 验证合并规则（物品与背包.md §3 规则表）。
func TestMerge(t *testing.T) {
	reg := loadItemReg(t)
	inv := New(reg)

	// 放入 30 个木板 → 合并到 34 个
	rem := inv.Add(item.Stack{Name: "oak_planks", Count: 30})
	if !rem.Empty() {
		t.Fatal("30 个木板应全部放入")
	}
	rem = inv.Add(item.Stack{Name: "oak_planks", Count: 34})
	if !rem.Empty() {
		t.Fatal("34 个木板应合并入同一槽")
	}
	// 64 上限：再放 10 应进入新槽（槽 0 已满 64）
	rem = inv.Add(item.Stack{Name: "oak_planks", Count: 10})
	if !rem.Empty() {
		t.Fatalf("剩余期望空，实际 %d", rem.Count)
	}
	if inv.Slots[1].Name != "oak_planks" || inv.Slots[1].Count != 10 {
		t.Fatalf("槽 1 期望 10 个木板，实际 %+v", inv.Slots[1])
	}
}

// TestRemove 验证取出物品。
func TestRemove(t *testing.T) {
	reg := loadItemReg(t)
	inv := New(reg)
	inv.Add(item.Stack{Name: "stick", Count: 16})
	if !inv.Remove("stick", 5) {
		t.Fatal("应能取出 5 个")
	}
	if inv.Remove("stick", 20) {
		t.Fatal("不足 20 个不应成功")
	}
	if !inv.Remove("stick", 11) {
		t.Fatal("应能取出剩余 11 个")
	}
}

// TestSelected 验证选中槽。
func TestSelected(t *testing.T) {
	reg := loadItemReg(t)
	inv := New(reg)
	inv.Slots[3] = item.Stack{Name: "torch", Count: 8}
	inv.Selected = 3
	if s := inv.SelectedStack(); s.Name != "torch" || s.Count != 8 {
		t.Fatalf("选中槽异常: %+v", s)
	}
}

func TestCanPlaceArmor(t *testing.T) {
	reg := loadItemReg(t)
	planks := item.Stack{Name: "oak_planks", Count: 1}
	helm := item.Stack{Name: "iron_helmet", Count: 1}
	if CanPlace(reg, SlotHelmet, planks) {
		t.Fatal("盔甲槽应拒收木板")
	}
	if !CanPlace(reg, SlotHelmet, helm) {
		t.Fatal("头盔槽应接收铁头盔")
	}
	if CanPlace(reg, SlotChest, helm) {
		t.Fatal("胸甲槽应拒收头盔")
	}
	if !CanPlace(reg, SlotOffhand, item.Stack{Name: "shield", Count: 1}) {
		t.Fatal("副手应接收盾")
	}
	if CanPlace(reg, SlotOffhand, planks) {
		t.Fatal("副手应拒收木板")
	}
}

func TestClickRightHalf(t *testing.T) {
	slot := item.Stack{Name: "oak_planks", Count: 5}
	ns, nh := ClickRight(slot, item.Stack{}, 64, true)
	if nh.Count != 3 || ns.Count != 2 {
		t.Fatalf("空手右键应拿一半向上取整：槽=%d 手=%d", ns.Count, nh.Count)
	}
	ns, nh = ClickRight(item.Stack{}, nh, 64, true)
	if ns.Count != 1 || nh.Count != 2 {
		t.Fatalf("手持右键应放 1 个：槽=%d 手=%d", ns.Count, nh.Count)
	}
}

func TestShiftHotbarMain(t *testing.T) {
	reg := loadItemReg(t)
	inv := New(reg)
	inv.Slots[0] = item.Stack{Name: "stick", Count: 8}
	if !inv.ShiftFromInv(0) {
		t.Fatal("热键栏 Shift 应移到主区")
	}
	if !inv.Slots[0].Empty() || inv.Slots[9].Name != "stick" || inv.Slots[9].Count != 8 {
		t.Fatalf("应进入主区槽 9，实际 hot=%+v main=%+v", inv.Slots[0], inv.Slots[9])
	}
}

func TestAddSkipsArmor(t *testing.T) {
	reg := loadItemReg(t)
	inv := New(reg)
	for i := 0; i < StorageSize; i++ {
		inv.Slots[i] = item.Stack{Name: "dirt", Count: 64}
	}
	rem := inv.Add(item.Stack{Name: "oak_planks", Count: 1})
	if rem.Empty() {
		t.Fatal("存储满时不应写入盔甲槽")
	}
	if !inv.Slots[SlotHelmet].Empty() {
		t.Fatal("盔甲槽应保持空")
	}
}

func TestSpreadEven(t *testing.T) {
	reg := loadItemReg(t)
	slots := []item.Stack{{}, {}, {}, {}, {}}
	ptrs := []*item.Stack{&slots[0], &slots[1], &slots[2], &slots[3], &slots[4]}
	held := SpreadEven(reg, item.Stack{Name: "oak_planks", Count: 5}, ptrs)
	if !held.Empty() {
		t.Fatalf("5 个应均分完，剩余 %+v", held)
	}
	for i, st := range slots {
		if st.Count != 1 {
			t.Fatalf("槽 %d 应各 1，实际 %+v", i, st)
		}
	}
}

func TestGather(t *testing.T) {
	reg := loadItemReg(t)
	inv := New(reg)
	inv.Slots[0] = item.Stack{Name: "stick", Count: 10}
	inv.Slots[9] = item.Stack{Name: "stick", Count: 20}
	held := inv.GatherStorage(item.Stack{}, "stick")
	if held.Count != 30 {
		t.Fatalf("应聚 30 棍，实际 %d", held.Count)
	}
}