package services

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

	"api-service/internal/config"

	"github.com/mashingan/smapping"
)

// VClaimService interface for VClaim operations
type VClaimService interface {
	Get(ctx context.Context, endpoint string, result interface{}) error
	Post(ctx context.Context, endpoint string, payload interface{}, result interface{}) error
	Put(ctx context.Context, endpoint string, payload interface{}, result interface{}) error
	Delete(ctx context.Context, endpoint string, result interface{}) error
	GetRawResponse(ctx context.Context, endpoint string) (*ResponDTO, error)
	PostRawResponse(ctx context.Context, endpoint string, payload interface{}) (*ResponDTO, error)
}

// Service struct for VClaim service
type Service struct {
	config     config.BpjsConfig
	httpClient *http.Client
}

// Response structures
type ResponMentahDTO struct {
	MetaData struct {
		Code    string `json:"code"`
		Message string `json:"message"`
	} `json:"metaData"`
	Response string `json:"response"`
}

type ResponDTO struct {
	MetaData struct {
		Code    string `json:"code"`
		Message string `json:"message"`
	} `json:"metaData"`
	Response interface{} `json:"response"`
}

// NewService creates a new VClaim service instance
func NewService(cfg config.BpjsConfig) VClaimService {
	service := &Service{
		config: cfg,
		httpClient: &http.Client{
			Timeout: cfg.Timeout,
		},
	}
	return service
}

// NewServiceFromConfig creates service from main config
func NewServiceFromConfig(cfg *config.Config) VClaimService {
	return NewService(cfg.Bpjs)
}

// NewServiceFromInterface creates service from interface (for backward compatibility)
func NewServiceFromInterface(cfg interface{}) (VClaimService, error) {
	var bpjsConfig config.BpjsConfig

	// Try to map from interface
	err := smapping.FillStruct(&bpjsConfig, smapping.MapFields(&cfg))
	if err != nil {
		return nil, fmt.Errorf("failed to map config: %w", err)
	}

	if bpjsConfig.Timeout == 0 {
		bpjsConfig.Timeout = 30 * time.Second
	}

	return NewService(bpjsConfig), nil
}

// SetHTTPClient allows custom http client configuration
func (s *Service) SetHTTPClient(client *http.Client) {
	s.httpClient = client
}

// prepareRequest prepares HTTP request with required headers
func (s *Service) prepareRequest(ctx context.Context, method, endpoint string, body io.Reader) (*http.Request, error) {
	fullURL := s.config.BaseURL + endpoint
	req, err := http.NewRequestWithContext(ctx, method, fullURL, body)
	if err != nil {
		return nil, fmt.Errorf("failed to create request: %w", err)
	}

	// Set headers using the SetHeader method
	consID, _, userKey, tstamp, xSignature := s.config.SetHeader()

	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("X-cons-id", consID)
	req.Header.Set("X-timestamp", tstamp)
	req.Header.Set("X-signature", xSignature)
	req.Header.Set("user_key", userKey)

	return req, nil
}

// processResponse processes response from VClaim API
func (s *Service) processResponse(res *http.Response) (*ResponDTO, error) {
	defer res.Body.Close()

	body, err := io.ReadAll(res.Body)
	if err != nil {
		return nil, fmt.Errorf("failed to read response body: %w", err)
	}

	// Check HTTP status
	if res.StatusCode >= 400 {
		return nil, fmt.Errorf("HTTP error: %d - %s", res.StatusCode, string(body))
	}

	// Parse raw response
	var respMentah ResponMentahDTO
	if err := json.Unmarshal(body, &respMentah); err != nil {
		return nil, fmt.Errorf("failed to unmarshal raw response: %w", err)
	}

	// Create final response
	finalResp := &ResponDTO{
		MetaData: respMentah.MetaData,
	}

	// If response is empty, return as is
	if respMentah.Response == "" {
		return finalResp, nil
	}

	// Decrypt response
	consID, secretKey, _, tstamp, _ := s.config.SetHeader()
	respDecrypt, err := ResponseVclaim(respMentah.Response, consID+secretKey+tstamp)
	if err != nil {
		return nil, fmt.Errorf("failed to decrypt response: %w", err)
	}

	// Unmarshal decrypted response
	if respDecrypt != "" {
		if err := json.Unmarshal([]byte(respDecrypt), &finalResp.Response); err != nil {
			// If JSON unmarshal fails, store as string
			finalResp.Response = respDecrypt
		}
	}

	return finalResp, nil
}

// Get performs HTTP GET request
func (s *Service) Get(ctx context.Context, endpoint string, result interface{}) error {
	resp, err := s.GetRawResponse(ctx, endpoint)
	if err != nil {
		return err
	}

	return mapToResult(resp, result)
}

// Post performs HTTP POST request
func (s *Service) Post(ctx context.Context, endpoint string, payload interface{}, result interface{}) error {
	resp, err := s.PostRawResponse(ctx, endpoint, payload)
	if err != nil {
		return err
	}

	return mapToResult(resp, result)
}

// Put performs HTTP PUT request
func (s *Service) Put(ctx context.Context, endpoint string, payload interface{}, result interface{}) error {
	var buf bytes.Buffer
	if payload != nil {
		if err := json.NewEncoder(&buf).Encode(payload); err != nil {
			return fmt.Errorf("failed to encode payload: %w", err)
		}
	}

	req, err := s.prepareRequest(ctx, http.MethodPut, endpoint, &buf)
	if err != nil {
		return err
	}

	res, err := s.httpClient.Do(req)
	if err != nil {
		return fmt.Errorf("failed to execute PUT request: %w", err)
	}

	resp, err := s.processResponse(res)
	if err != nil {
		return err
	}

	return mapToResult(resp, result)
}

// Delete performs HTTP DELETE request
func (s *Service) Delete(ctx context.Context, endpoint string, result interface{}) error {
	req, err := s.prepareRequest(ctx, http.MethodDelete, endpoint, nil)
	if err != nil {
		return err
	}

	res, err := s.httpClient.Do(req)
	if err != nil {
		return fmt.Errorf("failed to execute DELETE request: %w", err)
	}

	resp, err := s.processResponse(res)
	if err != nil {
		return err
	}

	return mapToResult(resp, result)
}

// GetRawResponse returns raw response without mapping
func (s *Service) GetRawResponse(ctx context.Context, endpoint string) (*ResponDTO, error) {
	req, err := s.prepareRequest(ctx, http.MethodGet, endpoint, nil)
	if err != nil {
		return nil, err
	}

	res, err := s.httpClient.Do(req)
	if err != nil {
		return nil, fmt.Errorf("failed to execute GET request: %w", err)
	}

	return s.processResponse(res)
}

// PostRawResponse returns raw response without mapping
func (s *Service) PostRawResponse(ctx context.Context, endpoint string, payload interface{}) (*ResponDTO, error) {
	var buf bytes.Buffer
	if payload != nil {
		if err := json.NewEncoder(&buf).Encode(payload); err != nil {
			return nil, fmt.Errorf("failed to encode payload: %w", err)
		}
	}

	req, err := s.prepareRequest(ctx, http.MethodPost, endpoint, &buf)
	if err != nil {
		return nil, err
	}

	res, err := s.httpClient.Do(req)
	if err != nil {
		return nil, fmt.Errorf("failed to execute POST request: %w", err)
	}

	return s.processResponse(res)
}

// mapToResult maps the final response to the result interface
func mapToResult(resp *ResponDTO, result interface{}) error {
	respBytes, err := json.Marshal(resp)
	if err != nil {
		return fmt.Errorf("failed to marshal final response: %w", err)
	}

	if err := json.Unmarshal(respBytes, result); err != nil {
		return fmt.Errorf("failed to unmarshal to result: %w", err)
	}

	return nil
}

// Backward compatibility functions
func GetRequest(endpoint string, cfg interface{}) interface{} {
	service, err := NewServiceFromInterface(cfg)
	if err != nil {
		fmt.Printf("Failed to create service: %v\n", err)
		return nil
	}

	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
	defer cancel()

	resp, err := service.GetRawResponse(ctx, endpoint)
	if err != nil {
		fmt.Printf("Failed to get response: %v\n", err)
		return nil
	}

	return resp
}

func PostRequest(endpoint string, cfg interface{}, data interface{}) interface{} {
	service, err := NewServiceFromInterface(cfg)
	if err != nil {
		fmt.Printf("Failed to create service: %v\n", err)
		return nil
	}

	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
	defer cancel()

	resp, err := service.PostRawResponse(ctx, endpoint, data)
	if err != nil {
		fmt.Printf("Failed to post response: %v\n", err)
		return nil
	}

	return resp
}