package counter

import (
	"sync"
	"testing"
)

func TestIncrConcurrent(t *testing.T) {
	var c Counter
	c.Init()

	var wg sync.WaitGroup
	for i := 0; i < 100; i++ {
		wg.Add(1)
		go func() {
			defer wg.Done()
			c.Incr("pv", 1)
		}()
	}
	wg.Wait()

	if got := c.Get("pv"); got != 100 {
		t.Errorf("并发 100 次 Incr 后 = %d, want 100", got)
	}
}

func TestSet(t *testing.T) {
	var c Counter
	c.Init()

	c.Set("k", 10)
	old := c.Set("k", 20)
	if old != 10 {
		t.Errorf("Set 返回旧值 = %d, want 10", old)
	}
	if got := c.Get("k"); got != 20 {
		t.Errorf("Set 后 Get = %d, want 20", got)
	}
}

func TestGetMissing(t *testing.T) {
	var c Counter
	c.Init()
	if got := c.Get("not-exist"); got != 0 {
		t.Errorf("不存在的 key Get = %d, want 0", got)
	}
}

func TestKeysIndependent(t *testing.T) {
	var c Counter
	c.Init()
	c.Incr("a", 1)
	c.Incr("b", 2)
	if c.Get("a") != 1 || c.Get("b") != 2 {
		t.Errorf("不同 key 应相互独立: a=%d b=%d", c.Get("a"), c.Get("b"))
	}
}