package officeconvertclient

import (
	"context"
	"fmt"
	"io"
	"net/http"
	"os"
	"path/filepath"
	"strings"

	officeconvertapiv1 "gitea.auvem.com/end/officeconvert/gen/go/officeconvertapi/v1"
)

// DownloadedArtifact records a downloaded slide image destination path.
type DownloadedArtifact struct {
	SlideIndex int32
	LocalPath  string
}

// DownloadArtifacts fetches all slide image URLs from a slide deck into outputDir.
func (c *Client) DownloadArtifacts(
	ctx context.Context,
	slideDeck *officeconvertapiv1.SlideDeck,
	outputDir string,
) ([]DownloadedArtifact, error) {
	if slideDeck == nil {
		return nil, fmt.Errorf("slide deck is nil")
	}
	if err := os.MkdirAll(outputDir, 0o755); err != nil {
		return nil, fmt.Errorf("create output directory: %w", err)
	}

	downloaded := make([]DownloadedArtifact, 0, len(slideDeck.Slides))
	for _, slide := range slideDeck.Slides {
		localPath := filepath.Join(outputDir, fmt.Sprintf("slide-%04d%s", slide.Index, inferImageExt(slide.ImageUrl)))
		if err := c.downloadFile(ctx, slide.ImageUrl, localPath); err != nil {
			return nil, err
		}
		downloaded = append(downloaded, DownloadedArtifact{
			SlideIndex: slide.Index,
			LocalPath:  localPath,
		})
	}

	return downloaded, nil
}

func (c *Client) downloadFile(ctx context.Context, sourceURL string, destinationPath string) error {
	req, err := http.NewRequestWithContext(ctx, http.MethodGet, sourceURL, nil)
	if err != nil {
		return fmt.Errorf("build download request: %w", err)
	}
	res, err := c.httpClient.Do(req)
	if err != nil {
		return fmt.Errorf("download artifact: %w", err)
	}
	defer res.Body.Close()

	if res.StatusCode < 200 || res.StatusCode >= 300 {
		return fmt.Errorf("download failed with status %d", res.StatusCode)
	}
	file, err := os.Create(destinationPath)
	if err != nil {
		return fmt.Errorf("create artifact file: %w", err)
	}
	defer file.Close()

	if _, err := io.Copy(file, res.Body); err != nil {
		return fmt.Errorf("write artifact file: %w", err)
	}
	return nil
}

func inferImageExt(imageURL string) string {
	switch {
	case strings.Contains(imageURL, ".jpeg") || strings.Contains(imageURL, ".jpg"):
		return ".jpg"
	case strings.Contains(imageURL, ".webp"):
		return ".webp"
	default:
		return ".png"
	}
}