// Package currencylayer provides a simple REST API with real-time and
// historical exchange rates for 168 world currencies, delivering currency pairs
// in universally usable JSON format - compatible with any of your applications.
// Spot exchange rate data is retrieved from several major forex data providers
// in real-time, validated, processed and delivered hourly, every 10 minutes, or
// even within the 60-second market window.
// Providing the most representative forex market value available
// ("midpoint" value) for every API request, the currencylayer API powers
// currency converters, mobile applications, financial software components and
// back-office systems all around the world.
// https://currencylayer.com/product for product information
// https://currencylayer.com/documentation for API documentation and supported
// functionality
package currencylayer

import (
	"context"
	"errors"
	"net/http"
	"net/url"
	"strconv"
	"strings"

	"github.com/thrasher-corp/gocryptotrader/common"
	"github.com/thrasher-corp/gocryptotrader/currency/forexprovider/base"
	"github.com/thrasher-corp/gocryptotrader/exchanges/request"
	"github.com/thrasher-corp/gocryptotrader/log"
)

// Setup sets appropriate values for CurrencyLayer
func (c *CurrencyLayer) Setup(config base.Settings) error {
	if config.APIKeyLvl < 0 || config.APIKeyLvl > 3 {
		log.Errorf(log.Global,
			"apikey incorrectly set in config.json for %s, please set appropriate account levels\n",
			config.Name)
		return errors.New("apikey set failure")
	}

	c.Name = config.Name
	c.APIKey = config.APIKey
	c.APIKeyLvl = config.APIKeyLvl
	c.Enabled = config.Enabled
	c.Verbose = config.Verbose
	c.PrimaryProvider = config.PrimaryProvider
	// Rate limit is based off a monthly counter - Open limit used.
	var err error
	c.Requester, err = request.New(c.Name,
		common.NewHTTPClientWithTimeout(base.DefaultTimeOut))
	return err
}

// GetRates is a wrapper function to return rates for GoCryptoTrader
func (c *CurrencyLayer) GetRates(baseCurrency, symbols string) (map[string]float64, error) {
	return c.GetliveData(symbols, baseCurrency)
}

// GetSupportedCurrencies returns supported currencies
func (c *CurrencyLayer) GetSupportedCurrencies() ([]string, error) {
	var resp SupportedCurrencies

	if err := c.SendHTTPRequest(APIEndpointList, url.Values{}, &resp); err != nil {
		return nil, err
	}

	if !resp.Success {
		return nil, errors.New(resp.Error.Info)
	}

	currencies := make([]string, 0, len(resp.Currencies))
	for key := range resp.Currencies {
		currencies = append(currencies, key)
	}

	return currencies, nil
}

// GetliveData returns live quotes for foreign exchange currencies
func (c *CurrencyLayer) GetliveData(currencies, source string) (map[string]float64, error) {
	var resp LiveRates
	v := url.Values{}
	v.Set("currencies", currencies)
	v.Set("source", source)

	err := c.SendHTTPRequest(APIEndpointLive, v, &resp)
	if err != nil {
		return nil, err
	}

	if !resp.Success {
		return nil, errors.New(resp.Error.Info)
	}

	return resp.Quotes, nil
}

// GetHistoricalData returns historical exchange rate data for every past day of
// the last 16 years.
func (c *CurrencyLayer) GetHistoricalData(date string, currencies []string, source string) (map[string]float64, error) {
	var resp HistoricalRates
	v := url.Values{}
	v.Set("currencies", strings.Join(currencies, ","))
	v.Set("source", source)
	v.Set("date", date)

	err := c.SendHTTPRequest(APIEndpointHistorical, v, &resp)
	if err != nil {
		return nil, err
	}

	if !resp.Success {
		return nil, errors.New(resp.Error.Info)
	}

	return resp.Quotes, nil
}

// Convert converts one currency amount to another currency amount.
func (c *CurrencyLayer) Convert(from, to, date string, amount float64) (float64, error) {
	if c.APIKeyLvl >= AccountBasic {
		return 0, errors.New("insufficient API privileges, upgrade to basic to use this function")
	}

	var resp ConversionRate

	v := url.Values{}
	v.Set("from", from)
	v.Set("to", to)
	v.Set("amount", strconv.FormatFloat(amount, 'f', -1, 64))
	v.Set("date", date)

	err := c.SendHTTPRequest(APIEndpointConversion, v, &resp)
	if err != nil {
		return resp.Result, err
	}

	if !resp.Success {
		return resp.Result, errors.New(resp.Error.Info)
	}
	return resp.Result, nil
}

// QueryTimeFrame returns historical exchange rates for a time-period.
// (maximum range: 365 days)
func (c *CurrencyLayer) QueryTimeFrame(startDate, endDate, baseCurrency string, currencies []string) (map[string]interface{}, error) {
	if c.APIKeyLvl >= AccountPro {
		return nil, errors.New("insufficient API privileges, upgrade to basic to use this function")
	}

	var resp TimeFrame

	v := url.Values{}
	v.Set("start_date", startDate)
	v.Set("end_date", endDate)
	v.Set("base", baseCurrency)
	v.Set("currencies", strings.Join(currencies, ","))

	err := c.SendHTTPRequest(APIEndpointTimeframe, v, &resp)
	if err != nil {
		return nil, err
	}

	if !resp.Success {
		return nil, errors.New(resp.Error.Info)
	}
	return resp.Quotes, nil
}

// QueryCurrencyChange returns the change (both margin and percentage) of one or
// more currencies, relative to a Source Currency, within a specific
// time-frame (optional).
func (c *CurrencyLayer) QueryCurrencyChange(startDate, endDate, baseCurrency string, currencies []string) (map[string]Changes, error) {
	if c.APIKeyLvl != AccountEnterprise {
		return nil, errors.New("insufficient API privileges, upgrade to basic to use this function")
	}
	var resp ChangeRate

	v := url.Values{}
	v.Set("start_date", startDate)
	v.Set("end_date", endDate)
	v.Set("base", baseCurrency)
	v.Set("currencies", strings.Join(currencies, ","))

	err := c.SendHTTPRequest(APIEndpointChange, v, &resp)
	if err != nil {
		return nil, err
	}

	if !resp.Success {
		return nil, errors.New(resp.Error.Info)
	}
	return resp.Quotes, nil
}

// SendHTTPRequest sends a HTTP request, if account is not free it automatically
// upgrades request to SSL.
func (c *CurrencyLayer) SendHTTPRequest(endPoint string, values url.Values, result interface{}) error {
	var path string
	values.Set("access_key", c.APIKey)

	var auth bool
	if c.APIKeyLvl == AccountFree {
		path = APIEndpointURL + endPoint + "?"
	} else {
		auth = true
		path = APIEndpointURLSSL + endPoint + "?"
	}
	path += values.Encode()
	item := &request.Item{
		Method:      http.MethodGet,
		Path:        path,
		Result:      &result,
		AuthRequest: auth,
		Verbose:     c.Verbose}
	return c.Requester.SendPayload(context.TODO(), request.Unset, func() (*request.Item, error) {
		return item, nil
	})
}