// Package file contains file service implementation for tgtest server.
package file

import (
	"go.mau.fi/mautrix-telegram/pkg/gotd/tg"
	"go.mau.fi/mautrix-telegram/pkg/gotd/tgtest"
	"go.mau.fi/mautrix-telegram/pkg/gotd/tgtest/services"
)

// Service is a Telegram file service.
type Service struct {
	storage Storage
	// Size of part to use in tg.FileHash.
	hashPartSize int
	// Size of range to return in upload.getFileHashes.
	hashRangeSize int
}

// NewService creates new file Service.
func NewService(cfg Config) *Service {
	cfg.setDefaults()

	return &Service{
		storage:       cfg.Storage,
		hashPartSize:  cfg.HashPartSize,
		hashRangeSize: cfg.HashRangeSize,
	}
}

// OnMessage implements tgtest.Handler.
func (m *Service) OnMessage(server *tgtest.Server, req *tgtest.Request) error {
	id, err := req.Buf.PeekID()
	if err != nil {
		return err
	}

	switch id {
	case tg.UploadGetFileRequestTypeID:
		fileReq := tg.UploadGetFileRequest{}
		if err := fileReq.Decode(req.Buf); err != nil {
			return err
		}

		r, err := m.UploadGetFile(req.RequestCtx, &fileReq)
		if err != nil {
			return err
		}

		return server.SendResult(req, r)
	case tg.UploadGetFileHashesRequestTypeID:
		fileReq := tg.UploadGetFileHashesRequest{}
		if err := fileReq.Decode(req.Buf); err != nil {
			return err
		}

		r, err := m.UploadGetFileHashes(req.RequestCtx, &fileReq)
		if err != nil {
			return err
		}

		return server.SendResult(req, &tg.FileHashVector{Elems: r})
	case tg.UploadSaveFilePartRequestTypeID:
		fileReq := tg.UploadSaveFilePartRequest{}
		if err := fileReq.Decode(req.Buf); err != nil {
			return err
		}

		r, err := m.UploadSaveFilePart(req.RequestCtx, &fileReq)
		if err != nil {
			return err
		}

		return server.SendBool(req, r)
	case tg.UploadSaveBigFilePartRequestTypeID:
		fileReq := tg.UploadSaveBigFilePartRequest{}
		if err := fileReq.Decode(req.Buf); err != nil {
			return err
		}

		r, err := m.UploadSaveBigFilePart(req.RequestCtx, &fileReq)
		if err != nil {
			return err
		}

		return server.SendBool(req, r)
	default:
		return services.ErrMethodNotImplemented
	}
}

// Register registers service handlers.
func (m *Service) Register(dispatcher *tgtest.Dispatcher) {
	dispatcher.HandleFunc(tg.UploadGetFileRequestTypeID, m.OnMessage)
	dispatcher.HandleFunc(tg.UploadGetFileHashesRequestTypeID, m.OnMessage)
	dispatcher.HandleFunc(tg.UploadSaveFilePartRequestTypeID, m.OnMessage)
	dispatcher.HandleFunc(tg.UploadSaveBigFilePartRequestTypeID, m.OnMessage)
}