package services

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

// StorageClient interacts with Supabase Storage via REST API.
type StorageClient struct {
	baseURL    string
	serviceKey string
	httpClient *http.Client
}

func NewStorageClient(supabaseURL, serviceKey string) *StorageClient {
	return &StorageClient{
		baseURL:    supabaseURL,
		serviceKey: serviceKey,
		httpClient: &http.Client{},
	}
}

// Upload stores a file in the given bucket at the specified path.
func (s *StorageClient) Upload(ctx context.Context, bucket, path, contentType string, data io.Reader) error {
	url := fmt.Sprintf("%s/storage/v1/object/%s/%s", s.baseURL, bucket, path)

	req, err := http.NewRequestWithContext(ctx, "POST", url, data)
	if err != nil {
		return fmt.Errorf("creating upload request: %w", err)
	}

	req.Header.Set("Authorization", "Bearer "+s.serviceKey)
	req.Header.Set("Content-Type", contentType)
	req.Header.Set("x-upsert", "true")

	resp, err := s.httpClient.Do(req)
	if err != nil {
		return fmt.Errorf("uploading to storage: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK && resp.StatusCode != http.StatusCreated {
		body, _ := io.ReadAll(resp.Body)
		return fmt.Errorf("storage upload failed (status %d): %s", resp.StatusCode, string(body))
	}

	return nil
}

// Download retrieves a file from storage. Caller must close the returned ReadCloser.
func (s *StorageClient) Download(ctx context.Context, bucket, path string) (io.ReadCloser, string, error) {
	url := fmt.Sprintf("%s/storage/v1/object/%s/%s", s.baseURL, bucket, path)

	req, err := http.NewRequestWithContext(ctx, "GET", url, nil)
	if err != nil {
		return nil, "", fmt.Errorf("creating download request: %w", err)
	}

	req.Header.Set("Authorization", "Bearer "+s.serviceKey)

	resp, err := s.httpClient.Do(req)
	if err != nil {
		return nil, "", fmt.Errorf("downloading from storage: %w", err)
	}

	if resp.StatusCode != http.StatusOK {
		resp.Body.Close()
		if resp.StatusCode == http.StatusNotFound {
			return nil, "", fmt.Errorf("file not found in storage")
		}
		body, _ := io.ReadAll(resp.Body)
		return nil, "", fmt.Errorf("storage download failed (status %d): %s", resp.StatusCode, string(body))
	}

	ct := resp.Header.Get("Content-Type")
	return resp.Body, ct, nil
}

// Delete removes files from storage by their paths.
func (s *StorageClient) Delete(ctx context.Context, bucket string, paths []string) error {
	url := fmt.Sprintf("%s/storage/v1/object/%s", s.baseURL, bucket)

	body, err := json.Marshal(map[string][]string{"prefixes": paths})
	if err != nil {
		return fmt.Errorf("marshaling delete request: %w", err)
	}

	req, err := http.NewRequestWithContext(ctx, "DELETE", url, bytes.NewReader(body))
	if err != nil {
		return fmt.Errorf("creating delete request: %w", err)
	}

	req.Header.Set("Authorization", "Bearer "+s.serviceKey)
	req.Header.Set("Content-Type", "application/json")

	resp, err := s.httpClient.Do(req)
	if err != nil {
		return fmt.Errorf("deleting from storage: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK && resp.StatusCode != http.StatusNoContent {
		respBody, _ := io.ReadAll(resp.Body)
		return fmt.Errorf("storage delete failed (status %d): %s", resp.StatusCode, string(respBody))
	}

	return nil
}