package money_test

import (
	"errors"
	"testing"

	"github.com/wangjia/pay/internal/money"
)

func TestParseFormatRoundTrip(t *testing.T) {
	cases := []struct {
		s, cur string
		minor  int64
	}{
		{"12.3417", "USDT", 12341700},
		{"0.01", "CNY", 1},
		{"29.99", "USD", 2999},
		{"199.99", "CNY", 19999},
		{"1", "USDT", 1000000},
	}
	for _, c := range cases {
		got, err := money.Parse(c.s, c.cur)
		if err != nil || got != c.minor {
			t.Fatalf("Parse(%q,%s)=%d,%v want %d", c.s, c.cur, got, err, c.minor)
		}
		back, err := money.Format(c.minor, c.cur)
		if err != nil {
			t.Fatalf("Format(%d,%s): %v", c.minor, c.cur, err)
		}
		// round-trip 回同一 minor(去尾零后可能字符串不同,再 Parse 校验)
		again, _ := money.Parse(back, c.cur)
		if again != c.minor {
			t.Fatalf("round-trip %d → %q → %d", c.minor, back, again)
		}
	}
}

func TestParseErrors(t *testing.T) {
	if _, err := money.Parse("1.00", "JPYX"); err == nil {
		t.Fatal("未知币种应报错")
	}
	if _, err := money.Parse("0.001", "CNY"); err == nil {
		t.Fatal("超精度(CNY 3 位小数)应报错")
	}
	if _, err := money.Parse("abc", "CNY"); err == nil {
		t.Fatal("非数字应报错")
	}
}

func TestFormatUnknownCurrency(t *testing.T) {
	_, err := money.Format(123, "JPYX")
	if err == nil {
		t.Fatal("未知币种应报错")
	}
	if !errors.Is(err, money.ErrUnknownCurrency) {
		t.Fatalf("want ErrUnknownCurrency, got %v", err)
	}
}

func TestParseOverflow(t *testing.T) {
	// whole part fits int64 on its own, but whole*mult(+frac) overflows int64.
	if _, err := money.Parse("92233720368547759", "CNY"); err == nil {
		t.Fatal("整数部分过大导致 minor 溢出 int64 应报错")
	}
	if _, err := money.Parse("92233720368547758.07", "CNY"); err != nil {
		t.Fatalf("恰好等于 int64 上限不应报错: %v", err)
	}
}

func TestParseFormatNegative(t *testing.T) {
	minor, err := money.Parse("-12.34", "CNY")
	if err != nil {
		t.Fatalf("Parse(-12.34): %v", err)
	}
	if minor != -1234 {
		t.Fatalf("Parse(-12.34)=%d want -1234", minor)
	}
	back, err := money.Format(-1234, "CNY")
	if err != nil {
		t.Fatalf("Format(-1234): %v", err)
	}
	again, err := money.Parse(back, "CNY")
	if err != nil {
		t.Fatalf("Parse(%q): %v", back, err)
	}
	if again != -1234 {
		t.Fatalf("round-trip -1234 → %q → %d", back, again)
	}
}