package shroom

import (
	"bytes"
	"errors"
	"fmt"
	"github.com/bouncepaw/mycorrhiza/files"
	"github.com/bouncepaw/mycorrhiza/history"
	"github.com/bouncepaw/mycorrhiza/hyphae"
	"github.com/bouncepaw/mycorrhiza/hyphae/backlinks"
	"github.com/bouncepaw/mycorrhiza/l18n"
	"github.com/bouncepaw/mycorrhiza/mimetype"
	"github.com/bouncepaw/mycorrhiza/user"
	"io"
	"log"
	"mime/multipart"
	"os"
	"path/filepath"
)

func historyMessageForTextUpload(h hyphae.Hypha, userMessage string) string {
	var verb string
	switch h.(type) {
	case *hyphae.EmptyHypha:
		verb = "Create"
	default:
		verb = "Edit"
	}

	if userMessage == "" {
		return fmt.Sprintf("%s ‘%s’", verb, h.CanonicalName())
	}
	return fmt.Sprintf("%s ‘%s’: %s", verb, h.CanonicalName(), userMessage)
}

func writeTextToDisk(h hyphae.ExistingHypha, data []byte, hop *history.Op) error {
	if err := os.MkdirAll(filepath.Dir(h.TextFilePath()), 0777); err != nil {
		return err
	}

	if err := os.WriteFile(h.TextFilePath(), data, 0666); err != nil {
		return err
	}
	hop.WithFiles(h.TextFilePath())

	return nil
}

// UploadText edits the hypha's text part and makes a history record about that.
func UploadText(h hyphae.Hypha, data []byte, userMessage string, u *user.User, lc *l18n.Localizer) (hop *history.Op, errtitle string) {
	hop = history.
		Operation(history.TypeEditText).
		WithMsg(historyMessageForTextUpload(h, userMessage)).
		WithUser(u)

	// Privilege check
	if !u.CanProceed("upload-text") {
		rejectEditLog(h, u, "no rights")
		return hop.WithErrAbort(errors.New(lc.Get("ui.act_norights_edit"))), lc.Get("ui.act_no_rights")
	}

	// Hypha name exploit check
	if !hyphae.IsValidName(h.CanonicalName()) {
		// We check for the name only. I suppose the filepath would be valid as well.
		err := errors.New("invalid hypha name")
		return hop.WithErrAbort(err), err.Error()
	}

	// Empty data check
	if len(bytes.TrimSpace(data)) == 0 { // if nothing but whitespace
		switch h.(type) {
		case *hyphae.EmptyHypha:
			// It's ok, just like cancel button.
			return hop.Abort(), ""
		case *hyphae.MediaHypha:
			// Writing no description, it's ok, just like cancel button.
			return hop.Abort(), ""
		case *hyphae.TextualHypha:
			// What do you want passing nothing for a textual hypha?
			return hop.WithErrAbort(errors.New("No data passed")), "Empty"
		}
	}

	// At this point, we have a savable user-generated Mycomarkup document. Gotta save it.

	switch h := h.(type) {
	case *hyphae.EmptyHypha:
		H := hyphae.ExtendEmptyToTextual(h, filepath.Join(files.HyphaeDir(), h.CanonicalName()+".myco"))

		err := writeTextToDisk(H, data, hop)
		if err != nil {
			return hop.WithErrAbort(err), err.Error()
		}

		hyphae.Insert(H)
	case *hyphae.MediaHypha:
		oldText, err := FetchTextFile(h)
		if err != nil {
			return hop.WithErrAbort(err), err.Error()
		}

		// TODO: that []byte(...) part should be removed
		if bytes.Compare(data, []byte(oldText)) == 0 {
			// No changes! Just like cancel button
			return hop.Abort(), ""
		}

		err = writeTextToDisk(h, data, hop)
		if err != nil {
			return hop.WithErrAbort(err), err.Error()
		}

		backlinks.UpdateBacklinksAfterEdit(h, oldText)
	case *hyphae.TextualHypha:
		oldText, err := FetchTextFile(h)
		if err != nil {
			return hop.WithErrAbort(err), err.Error()
		}

		// TODO: that []byte(...) part should be removed
		if bytes.Compare(data, []byte(oldText)) == 0 {
			// No changes! Just like cancel button
			return hop.Abort(), ""
		}

		err = writeTextToDisk(h, data, hop)
		if err != nil {
			return hop.WithErrAbort(err), err.Error()
		}

		backlinks.UpdateBacklinksAfterEdit(h, oldText)
	}

	return hop.Apply(), ""
}

func historyMessageForMediaUpload(h hyphae.Hypha, mime string) string {
	return fmt.Sprintf("Upload media for ‘%s’ with type ‘%s’", h.CanonicalName(), mime)
}

// writeMediaToDisk saves the given data with the given mime type for the given hypha to the disk and returns the path to the saved file and an error, if any.
func writeMediaToDisk(h hyphae.Hypha, mime string, data []byte) (string, error) {
	var (
		ext = mimetype.ToExtension(mime)
		// That's where the file will go
		uploadedFilePath = filepath.Join(files.HyphaeDir(), h.CanonicalName()+ext)
	)

	if err := os.MkdirAll(filepath.Dir(uploadedFilePath), 0777); err != nil {
		return uploadedFilePath, err
	}

	if err := os.WriteFile(uploadedFilePath, data, 0666); err != nil {
		return uploadedFilePath, err
	}
	return uploadedFilePath, nil
}

// UploadBinary edits the hypha's media part and makes a history record about that.
func UploadBinary(h hyphae.Hypha, mime string, file multipart.File, u *user.User, lc *l18n.Localizer) (*history.Op, string) {
	hop := history.
		Operation(history.TypeEditBinary).
		WithMsg(historyMessageForMediaUpload(h, mime)).
		WithUser(u)

	// Privilege check
	if !u.CanProceed("upload-binary") {
		rejectAttachLog(h, u, "no rights")
		return hop.WithErrAbort(errors.New(lc.Get("ui.act_norights_attach"))), lc.Get("ui.act_no_rights")
	}

	// Hypha name exploit check
	if !hyphae.IsValidName(h.CanonicalName()) {
		// We check for the name only. I suppose the filepath would be valid as well.
		err := errors.New("invalid hypha name")
		return hop.WithErrAbort(err), err.Error()
	}

	data, err := io.ReadAll(file)
	if err != nil {
		return hop.WithErrAbort(err), err.Error()
	}

	// Empty data check
	if len(data) == 0 {
		return hop.WithErrAbort(errors.New("No data passed")), "Empty"
	}

	// At this point, we have a savable media document. Gotta save it.

	uploadedFilePath, err := writeMediaToDisk(h, mime, data)
	if err != nil {
		return hop.WithErrAbort(err), err.Error()
	}

	switch h := h.(type) {
	case *hyphae.EmptyHypha:
		H := hyphae.ExtendEmptyToMedia(h, uploadedFilePath)
		hyphae.Insert(H)
	case *hyphae.TextualHypha:
		hyphae.Insert(hyphae.ExtendTextualToMedia(h, uploadedFilePath))
	case *hyphae.MediaHypha: // If this is not the first media the hypha gets
		prevFilePath := h.MediaFilePath()
		if prevFilePath != uploadedFilePath {
			if err := history.Rename(prevFilePath, uploadedFilePath); err != nil {
				return hop.WithErrAbort(err), err.Error()
			}
			log.Printf("Move ‘%s’ to ‘%s’\n", prevFilePath, uploadedFilePath)
			h.SetMediaFilePath(uploadedFilePath)
		}
	}

	return hop.WithFiles(uploadedFilePath).Apply(), ""
}