package accounts_test

import (
	"testing"

	"github.com/wangjia/pay/config"
	"github.com/wangjia/pay/internal/accounts"
)

func TestWeightedDeterministic(t *testing.T) {
	w := accounts.NewWeighted()
	cs := cands("a1", "a2", "a3")
	// 同一 OutTradeNo 必落同一账户(确定性,可复现)。
	first, _ := w.Pick("fake|global", cs, accounts.PickHint{OutTradeNo: "PAY-XYZ"})
	for i := 0; i < 5; i++ {
		got, _ := w.Pick("fake|global", cs, accounts.PickHint{OutTradeNo: "PAY-XYZ"})
		if got.AccountID != first.AccountID {
			t.Fatalf("同单号应恒定命中 %s, 第 %d 次得 %s", first.AccountID, i, got.AccountID)
		}
	}
}

func TestWeightedDistributesAndRespectsWeight(t *testing.T) {
	w := accounts.NewWeighted()
	// a1 权重 3,a2 权重 1 → 长跑大致 3:1。
	cs := []config.AccountConfig{
		{AccountID: "a1", Weight: 3},
		{AccountID: "a2", Weight: 1},
	}
	counts := map[string]int{}
	for i := 0; i < 4000; i++ {
		no := "PAY-" + string(rune('A'+i%26)) + string(rune('0'+i/26%10)) + string(rune('a'+i/260%26)) + string(rune('0'+i%7))
		got, _ := w.Pick("fake|global", cs, accounts.PickHint{OutTradeNo: no})
		counts[got.AccountID]++
	}
	if counts["a1"] == 0 || counts["a2"] == 0 {
		t.Fatalf("两账户都应被选中, got %+v", counts)
	}
	// a1 应显著多于 a2(3:1 容差:a1 至少是 a2 的 2 倍)。
	if counts["a1"] < counts["a2"]*2 {
		t.Fatalf("权重 3:1 未体现, got %+v", counts)
	}
}

func TestWeightedZeroWeightTreatedAsOne(t *testing.T) {
	w := accounts.NewWeighted()
	cs := []config.AccountConfig{{AccountID: "a1", Weight: 0}, {AccountID: "a2", Weight: 0}}
	counts := map[string]int{}
	for i := 0; i < 400; i++ {
		got, _ := w.Pick("fake|global", cs, accounts.PickHint{OutTradeNo: "N" + string(rune('0'+i%10)) + string(rune('a'+i%26))})
		counts[got.AccountID]++
	}
	if counts["a1"] == 0 || counts["a2"] == 0 {
		t.Fatalf("weight=0 应当 1 处理、两账户都可选, got %+v", counts)
	}
}