package domain

import (
	"strings"
	"testing"

	"github.com/shopspring/decimal"
)

func TestNewCurrency(t *testing.T) {
	tests := []struct {
		name      string
		code      string
		currName  string
		precision int
		wantErr   bool
	}{
		{
			name:      "valid currency",
			code:      "USD",
			currName:  "US Dollar",
			precision: 2,
			wantErr:   false,
		},
		{
			name:      "empty code",
			code:      "",
			currName:  "Test",
			precision: 2,
			wantErr:   true,
		},
		{
			name:      "whitespace code",
			code:      "   ",
			currName:  "Test",
			precision: 2,
			wantErr:   true,
		},
		{
			name:      "negative precision",
			code:      "BTC",
			currName:  "Bitcoin",
			precision: -1,
			wantErr:   true,
		},
		{
			name:      "lowercase code gets uppercase",
			code:      "btc",
			currName:  "Bitcoin",
			precision: 8,
			wantErr:   false,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			currency, err := NewCurrency(tt.code, tt.currName, tt.precision)
			
			if tt.wantErr {
				if err == nil {
					t.Errorf("NewCurrency() expected error but got none")
				}
				return
			}

			if err != nil {
				t.Errorf("NewCurrency() unexpected error: %v", err)
				return
			}

			expectedCode := strings.ToUpper(strings.TrimSpace(tt.code))
			if currency.Code != expectedCode {
				t.Errorf("NewCurrency() code = %s, want %s", currency.Code, expectedCode)
			}

			if currency.Precision != tt.precision {
				t.Errorf("NewCurrency() precision = %d, want %d", currency.Precision, tt.precision)
			}
		})
	}
}

func TestNewMoney(t *testing.T) {
	currency, _ := NewCurrency("USD", "US Dollar", 2)
	
	tests := []struct {
		name     string
		amount   string
		currency Currency
		wantErr  bool
	}{
		{
			name:     "valid amount",
			amount:   "123.45",
			currency: currency,
			wantErr:  false,
		},
		{
			name:     "zero amount",
			amount:   "0",
			currency: currency,
			wantErr:  false,
		},
		{
			name:     "empty amount",
			amount:   "",
			currency: currency,
			wantErr:  true,
		},
		{
			name:     "invalid amount format",
			amount:   "abc",
			currency: currency,
			wantErr:  true,
		},
		{
			name:     "negative amount",
			amount:   "-123.45",
			currency: currency,
			wantErr:  true,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			money, err := NewMoney(tt.amount, tt.currency)
			
			if tt.wantErr {
				if err == nil {
					t.Errorf("NewMoney() expected error but got none")
				}
				return
			}

			if err != nil {
				t.Errorf("NewMoney() unexpected error: %v", err)
				return
			}

			if money.Currency.Code != tt.currency.Code {
				t.Errorf("NewMoney() currency = %s, want %s", money.Currency.Code, tt.currency.Code)
			}
		})
	}
}

func TestNewRate(t *testing.T) {
	usd, _ := NewCurrency("USD", "US Dollar", 2)
	btc, _ := NewCurrency("BTC", "Bitcoin", 8)
	
	tests := []struct {
		name    string
		from    Currency
		to      Currency
		value   string
		source  string
		wantErr bool
	}{
		{
			name:    "valid rate",
			from:    usd,
			to:      btc,
			value:   "0.00001234",
			source:  "test",
			wantErr: false,
		},
		{
			name:    "same currencies",
			from:    usd,
			to:      usd,
			value:   "1.0",
			source:  "test",
			wantErr: true,
		},
		{
			name:    "negative rate",
			from:    usd,
			to:      btc,
			value:   "-0.00001234",
			source:  "test",
			wantErr: true,
		},
		{
			name:    "zero rate",
			from:    usd,
			to:      btc,
			value:   "0",
			source:  "test",
			wantErr: true,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			value, _ := decimal.NewFromString(tt.value)
			rate, err := NewRate(tt.from, tt.to, value, tt.source)
			
			if tt.wantErr {
				if err == nil {
					t.Errorf("NewRate() expected error but got none")
				}
				return
			}

			if err != nil {
				t.Errorf("NewRate() unexpected error: %v", err)
				return
			}

			if rate.From.Code != tt.from.Code {
				t.Errorf("NewRate() from = %s, want %s", rate.From.Code, tt.from.Code)
			}

			if rate.To.Code != tt.to.Code {
				t.Errorf("NewRate() to = %s, want %s", rate.To.Code, tt.to.Code)
			}
		})
	}
}