package accounts_test

import (
	"errors"
	"testing"

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

func TestLimitAwareFiltersOverLimit(t *testing.T) {
	usage := accounts.NewMemUsage()
	usage.Add("a1", 9000) // a1 今日已用 9000
	la := accounts.NewLimitAware(accounts.NewRoundRobin(), usage)
	cs := []config.AccountConfig{
		{AccountID: "a1", DailyLimit: 10000}, // 9000+2000=11000 > 10000 → 排除
		{AccountID: "a2", DailyLimit: 10000}, // 0+2000 <= 10000 → 合格
	}
	for i := 0; i < 3; i++ {
		got, err := la.Pick("fake|global", cs, accounts.PickHint{AmountMinor: 2000})
		if err != nil || got.AccountID != "a2" {
			t.Fatalf("越限的 a1 应被过滤、只剩 a2, got %v err %v", got.AccountID, err)
		}
	}
}

func TestLimitAwareZeroLimitIsUnlimited(t *testing.T) {
	usage := accounts.NewMemUsage()
	usage.Add("a1", 1_000_000)
	la := accounts.NewLimitAware(accounts.NewRoundRobin(), usage)
	cs := []config.AccountConfig{{AccountID: "a1", DailyLimit: 0}} // 0=不限
	got, err := la.Pick("fake|global", cs, accounts.PickHint{AmountMinor: 999})
	if err != nil || got.AccountID != "a1" {
		t.Fatalf("DailyLimit=0 应不限, got %v err %v", got.AccountID, err)
	}
}

func TestLimitAwareAllOverLimit(t *testing.T) {
	usage := accounts.NewMemUsage()
	usage.Add("a1", 10000)
	la := accounts.NewLimitAware(accounts.NewRoundRobin(), usage)
	cs := []config.AccountConfig{{AccountID: "a1", DailyLimit: 10000}}
	if _, err := la.Pick("fake|global", cs, accounts.PickHint{AmountMinor: 1}); !errors.Is(err, accounts.ErrNoAccount) {
		t.Fatalf("全部越限应 ErrNoAccount, got %v", err)
	}
}

func TestNopUsageDegradesToBase(t *testing.T) {
	la := accounts.NewLimitAware(accounts.NewRoundRobin(), accounts.NopUsage{})
	cs := []config.AccountConfig{
		{AccountID: "a1", DailyLimit: 100}, {AccountID: "a2", DailyLimit: 100},
	}
	// 空用量源 → 谁都不越限 → 行为 = round_robin。
	// 注:AmountMinor 须 <= DailyLimit,否则即便 used=0 单笔也会越限(0+amount>limit),
	// 那样测的是「单笔超限」而非「NopUsage 退化」,与用例名/注释矛盾——故取 10 而非 999。
	g1, _ := la.Pick("fake|global", cs, accounts.PickHint{AmountMinor: 10})
	g2, _ := la.Pick("fake|global", cs, accounts.PickHint{AmountMinor: 10})
	if g1.AccountID != "a1" || g2.AccountID != "a2" {
		t.Fatalf("NopUsage 下应退化为轮询 a1,a2, got %s,%s", g1.AccountID, g2.AccountID)
	}
}