package imapx

import (
	"context"

	"github.com/emersion/go-imap/v2"
	"github.com/emersion/go-imap/v2/imapclient"
)

// FolderMessageCount opens a folder read-only (EXAMINE) and returns how many
// messages it holds — used to plan an accurate overall progress total before
// copying begins. It does not fetch any message bodies.
func FolderMessageCount(c *imapclient.Client, folder string) (int64, error) {
	sel, err := c.Select(folder, &imap.SelectOptions{ReadOnly: true}).Wait()
	if err != nil {
		return 0, err
	}
	return int64(sel.NumMessages), nil
}

// ListFolders returns the mailbox names visible on an already-connected, logged-in client.
func ListFolders(c *imapclient.Client) ([]string, error) {
	mboxes, err := c.List("", "*", nil).Collect()
	if err != nil {
		return nil, err
	}
	names := make([]string, 0, len(mboxes))
	for _, m := range mboxes {
		names = append(names, m.Mailbox)
	}
	return names, nil
}

func TestLogin(ctx context.Context, ep Endpoint, login, pass string) ([]string, error) {
	c, err := Connect(ctx, ep)
	if err != nil {
		return nil, err
	}
	defer func() { _ = c.Logout().Wait() }()
	if err := c.Login(login, pass).Wait(); err != nil {
		return nil, err
	}
	mboxes, err := c.List("", "*", nil).Collect()
	if err != nil {
		return nil, err
	}
	names := make([]string, 0, len(mboxes))
	for _, m := range mboxes {
		names = append(names, m.Mailbox)
	}
	return names, nil
}