package store

import (
	"fmt"
	"io"
	"log"
	"net/mail"
	"path/filepath"
	"strings"
)

type Message struct {
	Maildir Maildir // maildir.name

	UID      uint64
	SeqNum   uint64
	Key      string
	Data     io.ReadCloser
	hdrCache mail.Header
}

// TODO: the cache is probably fine
func (m *Message) Header() (mail.Header, error) {
	if m.hdrCache != nil {
		return m.hdrCache, nil
	}

	hdr, err := m.Maildir.Header(m.Key)
	if err != nil {
		return nil, err
	}

	m.hdrCache = hdr
	return hdr, nil
}

func (m *Message) Len() uint64 {
	return 0 // FIXME
}

func (m *Message) HeaderString() (string, error) {
	var sb strings.Builder

	hdr, err := m.Header()
	if err != nil {
		return "", err
	}

	for k, vs := range hdr {
		for _, v := range vs {
			fmt.Fprintf(&sb, "%s: %s\r\n", k, v)
		}
	}
	return sb.String(), nil // FIXME
}

type MessageInterface interface {
	CreateMessage(Message) error
}

// DeliverMessage takes the given message and delivers it to the correct maildir
// It does not call Close() on message.Data
func (c *concrete) CreateMessage(message Message) error {
	// TODO: recover from panics, assure Abort() is called for them
	maildir := message.Maildir

	delivery, err := maildir.filesystem.NewDelivery()
	if err != nil {
		return err
	}

	if _, err := io.Copy(delivery, message.Data); err != nil {
		delivery.Abort()
		return err
	}

	if err := delivery.Close(); err != nil {
		delivery.Abort()
		return err
	}

	// FIXME: this moves files in the maildir before the dovecot-uidlist is
	// updated. Not ideal.
	// FIXME: we're not
	keys, err := maildir.filesystem.Unseen()
	if err != nil {
		log.Printf("Failed moving messages from new/ to cur/: %v", err)
	}

	var filenames []string
	for _, key := range keys {
		filename, err := maildir.filesystem.Filename(key)
		if err != nil {
			log.Printf("Failed getting filename for unseen message %q: %v", key, err)
			continue
		}
		filenames = append(filenames, filepath.Base(filename))
	}

	// Don't bubble the error up here as delivery has succeeded, IMAP just
	// doesn't know it has. We don't want the client to attempt redelivery.
	//
	// FIXME: this is IMAP stuff that needs moving
	if err := maildir.uids.Append(filenames...); err != nil {
		log.Printf("Allocating UIDs for unseen messages failed: %v", err)
	}

	return nil
}