package model

import "testing"

// withLevelDefs 临时切换等级快照并在测试结束后恢复现场（快照为进程级全局态）
func withLevelDefs(t *testing.T, defs []LevelDef) {
	t.Helper()
	prev := LevelDefs()
	t.Cleanup(func() { ApplyLevelDefs(prev) })
	ApplyLevelDefs(defs)
}

func TestLevelOfDefault(t *testing.T) {
	withLevelDefs(t, DefaultLevelDefs())
	cases := []struct {
		total int
		want  int
	}{
		{0, 1},
		{49, 1},
		{50, 2},
		{51, 2},
		{199, 2},
		{200, 3},
		{500, 4},
		{1200, 5},
		{3000, 6},
		{7999, 6},
		{8000, 7},
		{1 << 30, 7},
		{-5, 1},
	}
	for _, c := range cases {
		if got := LevelOf(c.total); got != c.want {
			t.Errorf("LevelOf(%d) = %d, want %d", c.total, got, c.want)
		}
	}
}

func TestLevelOfCustomConfig(t *testing.T) {
	withLevelDefs(t, []LevelDef{
		{Threshold: 0, Color: "neutral"},
		{Threshold: 10, Color: "gold"},
		{Threshold: 100, Color: "info"},
	})
	cases := []struct {
		total int
		want  int
	}{
		{0, 1},
		{9, 1},
		{10, 2},
		{99, 2},
		{100, 3},
		{1 << 20, 3},
	}
	for _, c := range cases {
		if got := LevelOf(c.total); got != c.want {
			t.Errorf("LevelOf(%d) = %d, want %d", c.total, got, c.want)
		}
	}
}

func TestApplyLevelDefsFallback(t *testing.T) {
	withLevelDefs(t, DefaultLevelDefs())
	// 非法配置（首级阈值非 0、数量不足、非递增）一律回落默认表
	invalid := [][]LevelDef{
		{{Threshold: 10, Color: "gold"}, {Threshold: 50, Color: "info"}},
		{{Threshold: 0, Color: "neutral"}},
		{{Threshold: 0, Color: "neutral"}, {Threshold: 50, Color: "info"}, {Threshold: 50, Color: "ok"}},
		{{Threshold: 0, Color: "neutral"}, {Threshold: -1, Color: "info"}},
	}
	for _, defs := range invalid {
		ApplyLevelDefs(defs)
		got := LevelDefs()
		if len(got) != len(DefaultLevelDefs()) {
			t.Fatalf("ApplyLevelDefs(invalid) 未回落默认表: got %d levels", len(got))
		}
	}
}

func TestValidLevelDefs(t *testing.T) {
	valid := []LevelDef{{Threshold: 0, Color: "neutral"}, {Threshold: 1, Color: "gold"}}
	if !ValidLevelDefs(valid) {
		t.Errorf("ValidLevelDefs(合法两极) = false")
	}
	tooMany := make([]LevelDef, MaxLevelCount+1)
	for i := range tooMany {
		tooMany[i] = LevelDef{Threshold: i, Color: "gold"}
	}
	if ValidLevelDefs(tooMany) {
		t.Errorf("ValidLevelDefs(超上限) = true")
	}
}

func TestLevelDefsBoundaryCount(t *testing.T) {
	withLevelDefs(t, DefaultLevelDefs())
	defs := make([]LevelDef, MaxLevelCount)
	for i := range defs {
		defs[i] = LevelDef{Threshold: i * 10, Color: "gold"}
	}
	ApplyLevelDefs(defs)
	if got := LevelOf(1 << 30); got != MaxLevelCount {
		t.Errorf("LevelOf(极大值) = %d, want %d", got, MaxLevelCount)
	}
}