package currency

import (
	"Yimaru-Backend/internal/domain"
	"context"
	"encoding/json"
	"fmt"
	"net/http"
	"time"
)

type FixerFetcher struct {
	apiKey     string
	baseURL    string
	httpClient *http.Client
}

func NewFixerFetcher(apiKey string, baseURL string) *FixerFetcher {

	return &FixerFetcher{
		apiKey:     apiKey,
		baseURL:    baseURL,
		httpClient: &http.Client{Timeout: 10 * time.Second},
	}
}

type fixerResponse struct {
	Success bool               `json:"success"`
	Base    string             `json:"base"`
	Date    string             `json:"date"`
	Rates   map[string]float64 `json:"rates"`
}

func (f *FixerFetcher) FetchLatestRates(ctx context.Context, baseCurrency domain.IntCurrency) (map[domain.IntCurrency]float64, error) {
	url := fmt.Sprintf("%s/latest?base=%s", f.baseURL, baseCurrency)

	req, err := http.NewRequestWithContext(ctx, "GET", url, nil)
	if err != nil {
		return nil, fmt.Errorf("failed to create request: %w", err)
	}

	req.Header.Set("apikey", f.apiKey)

	resp, err := f.httpClient.Do(req)
	if err != nil {
		return nil, fmt.Errorf("failed to fetch rates: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("unexpected status code: %d", resp.StatusCode)
	}

	var result fixerResponse
	if err := json.NewDecoder(resp.Body).Decode(&result); err != nil {
		return nil, fmt.Errorf("failed to decode response: %w", err)
	}

	if !result.Success {
		return nil, fmt.Errorf("api returned unsuccessful response")
	}

	rates := make(map[domain.IntCurrency]float64)
	for currency, rate := range result.Rates {
		rates[domain.IntCurrency(currency)] = rate
	}

	return rates, nil
}