package obsimport

import (
	"archive/zip"
	"bufio"
	"context"
	"fmt"
	"io"
	"log"
	"mime"
	"os"
	"path/filepath"
	"strings"
	"time"

	"lmika.dev/lmika/weiro/models"
	"lmika.dev/lmika/weiro/providers/db"
	"lmika.dev/lmika/weiro/providers/uploadfiles"
	"lmika.dev/lmika/weiro/services/publisher"
)

type Service struct {
	db         *db.Provider
	up         *uploadfiles.Provider
	publisher  *publisher.Queue
	scratchDir string
}

func New(db *db.Provider, up *uploadfiles.Provider, publisher *publisher.Queue, scratchDir string) *Service {
	return &Service{
		db:         db,
		up:         up,
		publisher:  publisher,
		scratchDir: scratchDir,
	}
}

type ImportResult struct {
	PostsImported   int
	UploadsImported int
}

func (s *Service) ImportZip(ctx context.Context, zipPath string) (ImportResult, error) {
	site, ok := models.GetSite(ctx)
	if !ok {
		return ImportResult{}, models.SiteRequiredError
	}

	zr, err := zip.OpenReader(zipPath)
	if err != nil {
		return ImportResult{}, fmt.Errorf("open zip: %w", err)
	}
	defer zr.Close()

	var result ImportResult

	for _, f := range zr.File {
		if f.FileInfo().IsDir() {
			continue
		}

		ext := strings.ToLower(filepath.Ext(f.Name))
		if ext == ".md" || ext == ".markdown" {
			if err := s.importNote(ctx, site, f); err != nil {
				log.Printf("warn: skipping note %s: %v", f.Name, err)
				continue
			}
			result.PostsImported++
		} else if isAttachment(ext) {
			if err := s.importAttachment(ctx, site, f); err != nil {
				log.Printf("warn: skipping attachment %s: %v", f.Name, err)
				continue
			}
			result.UploadsImported++
		}
	}

	s.publisher.Queue(site)

	return result, nil
}

func (s *Service) importNote(ctx context.Context, site models.Site, f *zip.File) error {
	rc, err := f.Open()
	if err != nil {
		return err
	}
	defer rc.Close()

	data, err := io.ReadAll(rc)
	if err != nil {
		return err
	}

	body := stripFrontMatter(string(data))
	title := strings.TrimSuffix(filepath.Base(f.Name), filepath.Ext(f.Name))
	publishedAt := f.Modified
	if publishedAt.IsZero() {
		publishedAt = time.Now()
	}

	renderTZ, err := time.LoadLocation(site.Timezone)
	if err != nil {
		renderTZ = time.UTC
	}
	publishedAt = publishedAt.In(renderTZ)

	post := &models.Post{
		SiteID:      site.ID,
		GUID:        models.NewNanoID(),
		State:       models.StatePublished,
		Title:       title,
		Body:        body,
		CreatedAt:   time.Now(),
		UpdatedAt:   time.Now(),
		PublishedAt: publishedAt,
	}
	post.Slug = post.BestSlug()

	return s.db.SavePost(ctx, post)
}

func (s *Service) importAttachment(ctx context.Context, site models.Site, f *zip.File) error {
	rc, err := f.Open()
	if err != nil {
		return err
	}
	defer rc.Close()

	// Write to a temp file in scratch dir
	if err := os.MkdirAll(s.scratchDir, 0755); err != nil {
		return err
	}

	tmpFile, err := os.CreateTemp(s.scratchDir, "obsimport-*"+filepath.Ext(f.Name))
	if err != nil {
		return err
	}
	tmpPath := tmpFile.Name()

	if _, err := io.Copy(tmpFile, rc); err != nil {
		tmpFile.Close()
		os.Remove(tmpPath)
		return err
	}
	tmpFile.Close()

	filename := filepath.Base(f.Name)
	mimeType := mime.TypeByExtension(filepath.Ext(filename))
	if mimeType == "" {
		mimeType = "application/octet-stream"
	}

	stat, err := os.Stat(tmpPath)
	if err != nil {
		os.Remove(tmpPath)
		return err
	}

	newUploadGUID := models.NewNanoID()
	newTime := time.Now().UTC()
	newSlug := filepath.Join(
		fmt.Sprintf("%04d", newTime.Year()),
		fmt.Sprintf("%02d", newTime.Month()),
		newUploadGUID+filepath.Ext(filename),
	)

	newUpload := models.Upload{
		SiteID:    site.ID,
		GUID:      models.NewNanoID(),
		FileSize:  stat.Size(),
		MIMEType:  mimeType,
		Filename:  filename,
		CreatedAt: newTime,
		Slug:      newSlug,
	}
	if err := s.db.SaveUpload(ctx, &newUpload); err != nil {
		os.Remove(tmpPath)
		return err
	}

	if err := s.up.AdoptFile(site, newUpload, tmpPath); err != nil {
		os.Remove(tmpPath)
		return err
	}

	return nil
}

// stripFrontMatter removes YAML front matter (delimited by ---) from markdown content.
func stripFrontMatter(content string) string {
	scanner := bufio.NewScanner(strings.NewReader(content))

	// Check if the first line is a front matter delimiter
	if !scanner.Scan() {
		return content
	}
	firstLine := strings.TrimSpace(scanner.Text())
	if firstLine != "---" {
		return content
	}

	// Skip until the closing ---
	for scanner.Scan() {
		if strings.TrimSpace(scanner.Text()) == "---" {
			// Return everything after the closing delimiter
			var rest strings.Builder
			for scanner.Scan() {
				rest.WriteString(scanner.Text())
				rest.WriteString("\n")
			}
			return strings.TrimLeft(rest.String(), "\n")
		}
	}

	// No closing delimiter found, return original content
	return content
}

var attachmentExts = map[string]bool{
	".png": true, ".jpg": true, ".jpeg": true, ".gif": true, ".svg": true, ".webp": true,
	".bmp": true, ".ico": true, ".tiff": true, ".tif": true,
	".mp3": true, ".mp4": true, ".wav": true, ".ogg": true, ".webm": true,
	".pdf": true, ".doc": true, ".docx": true, ".xls": true, ".xlsx": true,
}

func isAttachment(ext string) bool {
	return attachmentExts[ext]
}