/*
   GoToSocial
   Copyright (C) 2021-2022 GoToSocial Authors admin@gotosocial.org

   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU Affero General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU Affero General Public License for more details.

   You should have received a copy of the GNU Affero General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

package federation

import (
	"context"
	"fmt"
	"net/url"

	"github.com/superseriousbusiness/activity/streams"
	"github.com/superseriousbusiness/gotosocial/internal/db"
	"github.com/superseriousbusiness/gotosocial/internal/federation/dereferencing"
	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
)

func (p *processor) GetOutbox(ctx context.Context, requestedUsername string, page bool, maxID string, minID string, requestURL *url.URL) (interface{}, gtserror.WithCode) {
	// get the account the request is referring to
	requestedAccount, err := p.db.GetLocalAccountByUsername(ctx, requestedUsername)
	if err != nil {
		return nil, gtserror.NewErrorNotFound(fmt.Errorf("database error getting account with username %s: %s", requestedUsername, err))
	}

	// authenticate the request
	requestingAccountURI, errWithCode := p.federator.AuthenticateFederatedRequest(ctx, requestedUsername)
	if errWithCode != nil {
		return nil, errWithCode
	}

	requestingAccount, err := p.federator.GetRemoteAccount(ctx, dereferencing.GetRemoteAccountParams{
		RequestingUsername: requestedUsername,
		RemoteAccountID:    requestingAccountURI,
	})
	if err != nil {
		return nil, gtserror.NewErrorNotAuthorized(err)
	}

	// authorize the request:
	// 1. check if a block exists between the requester and the requestee
	blocked, err := p.db.IsBlocked(ctx, requestedAccount.ID, requestingAccount.ID, true)
	if err != nil {
		return nil, gtserror.NewErrorInternalError(err)
	}
	if blocked {
		return nil, gtserror.NewErrorNotAuthorized(fmt.Errorf("block exists between accounts %s and %s", requestedAccount.ID, requestingAccount.ID))
	}

	var data map[string]interface{}
	// now there are two scenarios:
	// 1. we're asked for the whole collection and not a page -- we can just return the collection, with no items, but a link to 'first' page.
	// 2. we're asked for a specific page; this can be either the first page or any other page

	if !page {
		/*
			scenario 1: return the collection with no items
			we want something that looks like this:
			{
				"@context": "https://www.w3.org/ns/activitystreams",
				"id": "https://example.org/users/whatever/outbox",
				"type": "OrderedCollection",
				"first": "https://example.org/users/whatever/outbox?page=true",
				"last": "https://example.org/users/whatever/outbox?min_id=0&page=true"
			}
		*/
		collection, err := p.tc.OutboxToASCollection(ctx, requestedAccount.OutboxURI)
		if err != nil {
			return nil, gtserror.NewErrorInternalError(err)
		}

		data, err = streams.Serialize(collection)
		if err != nil {
			return nil, gtserror.NewErrorInternalError(err)
		}

		return data, nil
	}

	// scenario 2 -- get the requested page
	// limit pages to 30 entries per page
	publicStatuses, err := p.db.GetAccountStatuses(ctx, requestedAccount.ID, 30, true, true, maxID, minID, false, false, true)
	if err != nil && err != db.ErrNoEntries {
		return nil, gtserror.NewErrorInternalError(err)
	}

	outboxPage, err := p.tc.StatusesToASOutboxPage(ctx, requestedAccount.OutboxURI, maxID, minID, publicStatuses)
	if err != nil {
		return nil, gtserror.NewErrorInternalError(err)
	}
	data, err = streams.Serialize(outboxPage)
	if err != nil {
		return nil, gtserror.NewErrorInternalError(err)
	}

	return data, nil
}