package client

import (
	"bytes"
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"net/http"
	"strings"
	"time"

	"go-backend-template/config"
	"go-backend-template/internal/contract"
	"go-backend-template/internal/logger"
)

// DukcapilClient performs HTTPS calls to the Dukcapil 1:N face recognition endpoint (CALL_FN).
type DukcapilClient struct {
	cfg  config.Dukcapil
	http *http.Client
}

func NewDukcapilClient(cfg config.Dukcapil) *DukcapilClient {
	return &DukcapilClient{
		cfg: cfg,
		http: &http.Client{
			Timeout: cfg.Timeout(),
		},
	}
}

// FaceMatch performs a 1:N face match call. The image must already be base64 encoded.
func (c *DukcapilClient) FaceMatch(ctx context.Context, req *contract.FaceMatchRequest) (*contract.DukcapilFaceResponse, error) {
	if c.cfg.BaseURL == "" || c.cfg.CustomerID == "" || c.cfg.Methode == "" {
		return nil, errors.New("dukcapil: incomplete configuration")
	}

	   ip := req.IP
	   if strings.TrimSpace(ip) == "" {
		   ip = c.cfg.DefaultIP
	   }

	   body := contract.DukcapilFaceRequest{
		   TransactionID:     req.TransactionID,
		   TransactionSource: req.TransactionSource,
		   Threshold:         req.Threshold,
		   Image:             req.Image,
		   UserID:            c.cfg.UserID,
		   Password:          c.cfg.Password,
		   IP:                ip,
	   }

	payload, err := json.Marshal(body)
	if err != nil {
		return nil, fmt.Errorf("dukcapil: marshal request: %w", err)
	}

	url := fmt.Sprintf("%s/%s/%s",
		strings.TrimRight(c.cfg.BaseURL, "/"),
		c.cfg.CustomerID,
		c.cfg.Methode,
	)

	httpReq, err := http.NewRequestWithContext(ctx, http.MethodPost, url, bytes.NewReader(payload))
	if err != nil {
		return nil, fmt.Errorf("dukcapil: build request: %w", err)
	}
	httpReq.Header.Set("Accept", "application/json")
	httpReq.Header.Set("Content-Type", "application/json")

	start := time.Now()
	resp, err := c.http.Do(httpReq)
	if err != nil {
		return nil, fmt.Errorf("dukcapil: do request: %w", err)
	}
	defer resp.Body.Close()

	respBytes, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, fmt.Errorf("dukcapil: read response: %w", err)
	}

	logger.FromContext(ctx).Infof("DukcapilClient::FaceMatch -> status=%d duration=%s", resp.StatusCode, time.Since(start))

	if resp.StatusCode >= 500 {
		return nil, fmt.Errorf("dukcapil: upstream status %d: %s", resp.StatusCode, string(respBytes))
	}

	var out contract.DukcapilFaceResponse
	if err := json.Unmarshal(respBytes, &out); err != nil {
		return nil, fmt.Errorf("dukcapil: decode response: %w (body=%s)", err, string(respBytes))
	}
	return &out, nil
}