package writefreely

import (
	"fmt"
	"html/template"
	"io"
	"io/ioutil"
	"net/http"
	"os"
	"path/filepath"

	"github.com/hashicorp/go-multierror"
	"github.com/writeas/impart"
	wfimport "github.com/writeas/import"
	"github.com/writeas/web-core/log"
)

func viewImport(app *App, u *User, w http.ResponseWriter, r *http.Request) error {
	// Fetch extra user data
	p := NewUserPage(app, r, u, "Import", nil)

	c, err := app.db.GetCollections(u)
	if err != nil {
		return impart.HTTPError{http.StatusInternalServerError, fmt.Sprintf("unable to fetch collections: %v", err)}
	}

	d := struct {
		*UserPage
		Collections *[]Collection
		Flashes     []template.HTML
	}{
		UserPage:    p,
		Collections: c,
		Flashes:     []template.HTML{},
	}

	flashes, _ := getSessionFlashes(app, w, r, nil)
	for _, flash := range flashes {
		d.Flashes = append(d.Flashes, template.HTML(flash))
	}

	showUserPage(w, "import", d)
	return nil
}

func handleImport(app *App, u *User, w http.ResponseWriter, r *http.Request) error {
	// limit 10MB per submission
	r.ParseMultipartForm(10 << 20)
	files := r.MultipartForm.File["files"]
	var fileErrs []error
	for _, formFile := range files {
		// TODO: count uploaded files that succeed and report back with message
		file, err := formFile.Open()
		if err != nil {
			fileErrs = append(fileErrs, fmt.Errorf("failed to open form file: %s", formFile.Filename))
			log.Error("import textfile: open from form: %v", err)
			continue
		}
		defer file.Close()

		tempFile, err := ioutil.TempFile("", "post-upload-*.txt")
		if err != nil {
			fileErrs = append(fileErrs, fmt.Errorf("failed to create temporary file for: %s", formFile.Filename))
			log.Error("import textfile: create temp file: %v", err)
			continue
		}
		defer tempFile.Close()

		_, err = io.Copy(tempFile, file)
		if err != nil {
			fileErrs = append(fileErrs, fmt.Errorf("failed to copy file into temporary location: %s", formFile.Filename))
			log.Error("import textfile: copy to temp: %v", err)
			continue
		}

		info, err := tempFile.Stat()
		if err != nil {
			fileErrs = append(fileErrs, fmt.Errorf("failed to get file info of: %s", formFile.Filename))
			log.Error("import textfile: stat temp file: %v", err)
			continue
		}
		post, err := wfimport.FromFile(filepath.Join(os.TempDir(), info.Name()))
		if err == wfimport.ErrEmptyFile {
			// not a real error so don't log
			_ = addSessionFlash(app, w, r, fmt.Sprintf("%s was empty, import skipped", formFile.Filename), nil)
			continue
		} else if err != nil {
			fileErrs = append(fileErrs, fmt.Errorf("failed to read copy of %s", formFile.Filename))
			log.Error("import textfile: file to post: %v", err)
			continue
		}

		post.Collection = r.PostFormValue("collection")
		coll, _ := app.db.GetCollection(post.Collection)
		if coll == nil {
			coll = &Collection{
				ID: 0,
			}
		}

		submittedPost := SubmittedPost{
			Title:   &post.Title,
			Content: &post.Content,
			Font:    "norm",
		}
		if coll.ID != 0 && app.cfg.App.Federation {
			token, err := app.db.GetAccessToken(u.ID)
			if err != nil {
				fileErrs = append(fileErrs, fmt.Errorf("failed to authenticate uploading: %s", formFile.Filename))
				log.Error("import textfile: get accesstoken: %+v", err)
				continue
			}
			ownedPost, err := app.db.CreateOwnedPost(&submittedPost, token, coll.Alias, app.cfg.App.Host)
			if err != nil {
				fileErrs = append(fileErrs, fmt.Errorf("failed to create owned post for %s", formFile.Filename))
				log.Error("import textfile: create owned post: %v", err)
				continue
			}
			go federatePost(app, ownedPost, coll.ID, false)
		} else {
			_, err = app.db.CreatePost(u.ID, coll.ID, &submittedPost)
			if err != nil {
				fileErrs = append(fileErrs, fmt.Errorf("failed to create post from %s", formFile.Filename))
				log.Error("import textfile: create db post: %v", err)
				continue
			}
		}
	}
	if len(fileErrs) != 0 {
		_ = addSessionFlash(app, w, r, multierror.ListFormatFunc(fileErrs), nil)
	}

	return impart.HTTPError{http.StatusFound, "/me/import"}
}