package pop3

import (
	"context"
	"fmt"

	gopop3 "github.com/knadh/go-pop3"

	"internal-mail-skill/internal/config"
	"internal-mail-skill/internal/model"
)

type Fetcher struct {
	cfg config.POP3Config
}

func NewFetcher(cfg config.POP3Config) *Fetcher {
	return &Fetcher{cfg: cfg}
}

func (f *Fetcher) Fetch(ctx context.Context) ([]model.FetchedMessage, error) {
	if f.cfg.Host == "" {
		return nil, fmt.Errorf("POP3_HOST is required")
	}
	select {
	case <-ctx.Done():
		return nil, ctx.Err()
	default:
	}

	client := gopop3.New(gopop3.Opt{
		Host:        f.cfg.Host,
		Port:        f.cfg.Port,
		TLSEnabled:  f.cfg.UseTLS,
		DialTimeout: f.cfg.Timeout(),
	})
	conn, err := client.NewConn()
	if err != nil {
		return nil, fmt.Errorf("connect POP3: %w", err)
	}
	defer conn.Quit()

	if err := conn.Auth(f.cfg.Username, f.cfg.Password); err != nil {
		return nil, fmt.Errorf("POP3 auth: %w", err)
	}
	ids, err := conn.Uidl(0)
	if err != nil {
		return nil, fmt.Errorf("POP3 UIDL: %w", err)
	}
	out := make([]model.FetchedMessage, 0, len(ids))
	for _, item := range ids {
		select {
		case <-ctx.Done():
			return out, ctx.Err()
		default:
		}
		raw, err := conn.RetrRaw(item.ID)
		if err != nil {
			out = append(out, model.FetchedMessage{ServerID: item.ID, UID: item.UID, Error: fmt.Sprintf("POP3 RETR %d: %v", item.ID, err)})
			continue
		}
		out = append(out, model.FetchedMessage{
			ServerID: item.ID,
			UID:      item.UID,
			Raw:      raw.Bytes(),
		})
	}
	return out, nil
}