package staticjsonFinnhub

import (
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"net/url"
	"time"
)

const apiBaseURL = "https://finnhub.io/api/v1/"

// A client is the structure that will be used to consume the API
// endpoints. It holds the login credentials, http client/transport,
// rate limit information, and the login session timer.
type client struct {
	apiToken   string
	httpClient *http.Client
	transport  *http.Transport
}

// Send an HTTP GET request, and return the processed response
func (c *client) get(endpoint string, out interface{}, query url.Values) error {
	req, err := http.NewRequest("GET", apiBaseURL+endpoint+"?"+query.Encode(), nil)
	if err != nil {
		return err
	}
	req.Header.Add("X-Finnhub-Token", c.apiToken)

	res, err := c.httpClient.Do(req)
	if err != nil {
		return fmt.Errorf("http get request failed: %v", err)
	}

	err = c.processResponse(res, out)
	if err != nil {
		return err
	}
	return nil
}

// processResponse takes the body of an HTTP response, and either returns
// the error code, or unmarshalls the JSON response, extracts
// rate limit info, and places it into the object
// output parameter. This function closes the response body after reading it.
func (c *client) processResponse(res *http.Response, out interface{}) error {
	body, err := io.ReadAll(res.Body)
	res.Body.Close()
	if err != nil {
		return err
	}

	if res.StatusCode != 200 {
		return fmt.Errorf("got http response status '%d' but expected 200", res.StatusCode)
	}

	err = json.Unmarshal(body, out)
	if err != nil {
		return err
	}

	return nil
}

// newClient is the factory function for clients - takes an API token
func newClient(apiToken string) (*client, error) {
	transport := &http.Transport{
		ResponseHeaderTimeout: 5 * time.Second,
	}

	httpClient := &http.Client{
		Transport: transport,
	}

	// Create a new client
	c := &client{
		apiToken:   apiToken,
		httpClient: httpClient,
		transport:  transport,
	}

	return c, nil
}