package veli

import (
	"bytes"
	"context"
	"crypto/hmac"
	"crypto/sha512"
	"encoding/base64"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"sort"
	"strings"
	"time"

	"github.com/SamuelTariku/FortuneBet-Backend/internal/config"
	"github.com/SamuelTariku/FortuneBet-Backend/internal/services/wallet"
)

type Client struct {
	http       *http.Client
	BaseURL    string
	OperatorID string
	SecretKey  string
	BrandID    string
	walletSvc  *wallet.Service
}

func NewClient(cfg *config.Config, walletSvc *wallet.Service) *Client {
	return &Client{
		http:       &http.Client{Timeout: 10 * time.Second},
		BaseURL:    cfg.VeliGames.BaseURL,
		OperatorID: cfg.VeliGames.OperatorID,
		SecretKey:  cfg.VeliGames.SecretKey,
		BrandID:    cfg.VeliGames.BrandID,
		walletSvc:  walletSvc,
	}
}

// Signature generator
func (c *Client) generateSignature(params map[string]string) (string, error) {
	keys := make([]string, 0, len(params))
	for k := range params {
		keys = append(keys, k)
	}
	sort.Strings(keys)

	var b strings.Builder
	for i, k := range keys {
		if i > 0 {
			b.WriteString(";")
		}
		b.WriteString(fmt.Sprintf("%s:%s", k, params[k]))
	}

	h := hmac.New(sha512.New, []byte(c.SecretKey))
	h.Write([]byte(b.String()))
	return fmt.Sprintf("%s:%s", c.OperatorID, base64.StdEncoding.EncodeToString(h.Sum(nil))), nil
}

// POST helper
func (c *Client) post(ctx context.Context, path string, body any, sigParams map[string]string, result any) error {
	data, _ := json.Marshal(body)
	sig, err := c.generateSignature(sigParams)
	if err != nil {
		return err
	}

	req, _ := http.NewRequestWithContext(ctx, "POST", c.BaseURL+path, bytes.NewReader(data))
	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("signature", sig)

	res, err := c.http.Do(req)
	if err != nil {
		return err
	}
	defer res.Body.Close()

	b, _ := io.ReadAll(res.Body)
	if res.StatusCode >= 400 {
		return fmt.Errorf("error: %s", b)
	}
	if result != nil {
		return json.Unmarshal(b, result)
	}
	return nil
}