/*
   GoToSocial
   Copyright (C) 2021 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 processing

import (
	"errors"
	"fmt"

	apimodel "github.com/superseriousbusiness/gotosocial/internal/api/model"
	"github.com/superseriousbusiness/gotosocial/internal/db"
	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
	"github.com/superseriousbusiness/gotosocial/internal/id"
	"github.com/superseriousbusiness/gotosocial/internal/oauth"
	"github.com/superseriousbusiness/gotosocial/internal/util"
)

// accountCreate does the dirty work of making an account and user in the database.
// It then returns a token to the caller, for use with the new account, as per the
// spec here: https://docs.joinmastodon.org/methods/accounts/
func (p *processor) AccountCreate(authed *oauth.Auth, form *apimodel.AccountCreateRequest) (*apimodel.Token, error) {
	l := p.log.WithField("func", "accountCreate")

	if err := p.db.IsEmailAvailable(form.Email); err != nil {
		return nil, err
	}

	if err := p.db.IsUsernameAvailable(form.Username); err != nil {
		return nil, err
	}

	// don't store a reason if we don't require one
	reason := form.Reason
	if !p.config.AccountsConfig.ReasonRequired {
		reason = ""
	}

	l.Trace("creating new username and account")
	user, err := p.db.NewSignup(form.Username, reason, p.config.AccountsConfig.RequireApproval, form.Email, form.Password, form.IP, form.Locale, authed.Application.ID)
	if err != nil {
		return nil, fmt.Errorf("error creating new signup in the database: %s", err)
	}

	l.Tracef("generating a token for user %s with account %s and application %s", user.ID, user.AccountID, authed.Application.ID)
	accessToken, err := p.oauthServer.GenerateUserAccessToken(authed.Token, authed.Application.ClientSecret, user.ID)
	if err != nil {
		return nil, fmt.Errorf("error creating new access token for user %s: %s", user.ID, err)
	}

	return &apimodel.Token{
		AccessToken: accessToken.GetAccess(),
		TokenType:   "Bearer",
		Scope:       accessToken.GetScope(),
		CreatedAt:   accessToken.GetAccessCreateAt().Unix(),
	}, nil
}

func (p *processor) AccountGet(authed *oauth.Auth, targetAccountID string) (*apimodel.Account, error) {
	targetAccount := &gtsmodel.Account{}
	if err := p.db.GetByID(targetAccountID, targetAccount); err != nil {
		if _, ok := err.(db.ErrNoEntries); ok {
			return nil, errors.New("account not found")
		}
		return nil, fmt.Errorf("db error: %s", err)
	}

	// lazily dereference things on the account if it hasn't been done yet
	var requestingUsername string
	if authed.Account != nil {
		requestingUsername = authed.Account.Username
	}
	if err := p.dereferenceAccountFields(targetAccount, requestingUsername, false); err != nil {
		p.log.WithField("func", "AccountGet").Debugf("dereferencing account: %s", err)
	}

	var mastoAccount *apimodel.Account
	var err error
	if authed.Account != nil && targetAccount.ID == authed.Account.ID {
		mastoAccount, err = p.tc.AccountToMastoSensitive(targetAccount)
	} else {
		mastoAccount, err = p.tc.AccountToMastoPublic(targetAccount)
	}
	if err != nil {
		return nil, fmt.Errorf("error converting account: %s", err)
	}
	return mastoAccount, nil
}

func (p *processor) AccountUpdate(authed *oauth.Auth, form *apimodel.UpdateCredentialsRequest) (*apimodel.Account, error) {
	l := p.log.WithField("func", "AccountUpdate")

	if form.Discoverable != nil {
		if err := p.db.UpdateOneByID(authed.Account.ID, "discoverable", *form.Discoverable, &gtsmodel.Account{}); err != nil {
			return nil, fmt.Errorf("error updating discoverable: %s", err)
		}
	}

	if form.Bot != nil {
		if err := p.db.UpdateOneByID(authed.Account.ID, "bot", *form.Bot, &gtsmodel.Account{}); err != nil {
			return nil, fmt.Errorf("error updating bot: %s", err)
		}
	}

	if form.DisplayName != nil {
		if err := util.ValidateDisplayName(*form.DisplayName); err != nil {
			return nil, err
		}
		if err := p.db.UpdateOneByID(authed.Account.ID, "display_name", *form.DisplayName, &gtsmodel.Account{}); err != nil {
			return nil, err
		}
	}

	if form.Note != nil {
		if err := util.ValidateNote(*form.Note); err != nil {
			return nil, err
		}
		if err := p.db.UpdateOneByID(authed.Account.ID, "note", *form.Note, &gtsmodel.Account{}); err != nil {
			return nil, err
		}
	}

	if form.Avatar != nil && form.Avatar.Size != 0 {
		avatarInfo, err := p.updateAccountAvatar(form.Avatar, authed.Account.ID)
		if err != nil {
			return nil, err
		}
		l.Tracef("new avatar info for account %s is %+v", authed.Account.ID, avatarInfo)
	}

	if form.Header != nil && form.Header.Size != 0 {
		headerInfo, err := p.updateAccountHeader(form.Header, authed.Account.ID)
		if err != nil {
			return nil, err
		}
		l.Tracef("new header info for account %s is %+v", authed.Account.ID, headerInfo)
	}

	if form.Locked != nil {
		if err := p.db.UpdateOneByID(authed.Account.ID, "locked", *form.Locked, &gtsmodel.Account{}); err != nil {
			return nil, err
		}
	}

	if form.Source != nil {
		if form.Source.Language != nil {
			if err := util.ValidateLanguage(*form.Source.Language); err != nil {
				return nil, err
			}
			if err := p.db.UpdateOneByID(authed.Account.ID, "language", *form.Source.Language, &gtsmodel.Account{}); err != nil {
				return nil, err
			}
		}

		if form.Source.Sensitive != nil {
			if err := p.db.UpdateOneByID(authed.Account.ID, "locked", *form.Locked, &gtsmodel.Account{}); err != nil {
				return nil, err
			}
		}

		if form.Source.Privacy != nil {
			if err := util.ValidatePrivacy(*form.Source.Privacy); err != nil {
				return nil, err
			}
			if err := p.db.UpdateOneByID(authed.Account.ID, "privacy", *form.Source.Privacy, &gtsmodel.Account{}); err != nil {
				return nil, err
			}
		}
	}

	// fetch the account with all updated values set
	updatedAccount := &gtsmodel.Account{}
	if err := p.db.GetByID(authed.Account.ID, updatedAccount); err != nil {
		return nil, fmt.Errorf("could not fetch updated account %s: %s", authed.Account.ID, err)
	}

	p.fromClientAPI <- gtsmodel.FromClientAPI{
		APObjectType:   gtsmodel.ActivityStreamsProfile,
		APActivityType: gtsmodel.ActivityStreamsUpdate,
		GTSModel:       updatedAccount,
		OriginAccount:  updatedAccount,
	}

	acctSensitive, err := p.tc.AccountToMastoSensitive(updatedAccount)
	if err != nil {
		return nil, fmt.Errorf("could not convert account into mastosensitive account: %s", err)
	}
	return acctSensitive, nil
}

func (p *processor) AccountStatusesGet(authed *oauth.Auth, targetAccountID string, limit int, excludeReplies bool, maxID string, pinned bool, mediaOnly bool) ([]apimodel.Status, gtserror.WithCode) {
	targetAccount := &gtsmodel.Account{}
	if err := p.db.GetByID(targetAccountID, targetAccount); err != nil {
		if _, ok := err.(db.ErrNoEntries); ok {
			return nil, gtserror.NewErrorNotFound(fmt.Errorf("no entry found for account id %s", targetAccountID))
		}
		return nil, gtserror.NewErrorInternalError(err)
	}

	statuses := []gtsmodel.Status{}
	apiStatuses := []apimodel.Status{}
	if err := p.db.GetStatusesByTimeDescending(targetAccountID, &statuses, limit, excludeReplies, maxID, pinned, mediaOnly); err != nil {
		if _, ok := err.(db.ErrNoEntries); ok {
			return apiStatuses, nil
		}
		return nil, gtserror.NewErrorInternalError(err)
	}

	for _, s := range statuses {
		visible, err := p.filter.StatusVisible(&s, authed.Account)
		if err != nil {
			return nil, gtserror.NewErrorInternalError(fmt.Errorf("error checking status visibility: %s", err))
		}
		if !visible {
			continue
		}

		apiStatus, err := p.tc.StatusToMasto(&s, authed.Account)
		if err != nil {
			return nil, gtserror.NewErrorInternalError(fmt.Errorf("error converting status to masto: %s", err))
		}

		apiStatuses = append(apiStatuses, *apiStatus)
	}

	return apiStatuses, nil
}

func (p *processor) AccountFollowersGet(authed *oauth.Auth, targetAccountID string) ([]apimodel.Account, gtserror.WithCode) {
	blocked, err := p.db.Blocked(authed.Account.ID, targetAccountID)
	if err != nil {
		return nil, gtserror.NewErrorInternalError(err)
	}

	if blocked {
		return nil, gtserror.NewErrorNotFound(fmt.Errorf("block exists between accounts"))
	}

	followers := []gtsmodel.Follow{}
	accounts := []apimodel.Account{}
	if err := p.db.GetFollowersByAccountID(targetAccountID, &followers, false); err != nil {
		if _, ok := err.(db.ErrNoEntries); ok {
			return accounts, nil
		}
		return nil, gtserror.NewErrorInternalError(err)
	}

	for _, f := range followers {
		blocked, err := p.db.Blocked(authed.Account.ID, f.AccountID)
		if err != nil {
			return nil, gtserror.NewErrorInternalError(err)
		}
		if blocked {
			continue
		}

		a := &gtsmodel.Account{}
		if err := p.db.GetByID(f.AccountID, a); err != nil {
			if _, ok := err.(db.ErrNoEntries); ok {
				continue
			}
			return nil, gtserror.NewErrorInternalError(err)
		}

		// derefence account fields in case we haven't done it already
		if err := p.dereferenceAccountFields(a, authed.Account.Username, false); err != nil {
			// don't bail if we can't fetch them, we'll try another time
			p.log.WithField("func", "AccountFollowersGet").Debugf("error dereferencing account fields: %s", err)
		}

		account, err := p.tc.AccountToMastoPublic(a)
		if err != nil {
			return nil, gtserror.NewErrorInternalError(err)
		}
		accounts = append(accounts, *account)
	}
	return accounts, nil
}

func (p *processor) AccountFollowingGet(authed *oauth.Auth, targetAccountID string) ([]apimodel.Account, gtserror.WithCode) {
	blocked, err := p.db.Blocked(authed.Account.ID, targetAccountID)
	if err != nil {
		return nil, gtserror.NewErrorInternalError(err)
	}

	if blocked {
		return nil, gtserror.NewErrorNotFound(fmt.Errorf("block exists between accounts"))
	}

	following := []gtsmodel.Follow{}
	accounts := []apimodel.Account{}
	if err := p.db.GetFollowingByAccountID(targetAccountID, &following); err != nil {
		if _, ok := err.(db.ErrNoEntries); ok {
			return accounts, nil
		}
		return nil, gtserror.NewErrorInternalError(err)
	}

	for _, f := range following {
		blocked, err := p.db.Blocked(authed.Account.ID, f.AccountID)
		if err != nil {
			return nil, gtserror.NewErrorInternalError(err)
		}
		if blocked {
			continue
		}

		a := &gtsmodel.Account{}
		if err := p.db.GetByID(f.TargetAccountID, a); err != nil {
			if _, ok := err.(db.ErrNoEntries); ok {
				continue
			}
			return nil, gtserror.NewErrorInternalError(err)
		}

		// derefence account fields in case we haven't done it already
		if err := p.dereferenceAccountFields(a, authed.Account.Username, false); err != nil {
			// don't bail if we can't fetch them, we'll try another time
			p.log.WithField("func", "AccountFollowingGet").Debugf("error dereferencing account fields: %s", err)
		}

		account, err := p.tc.AccountToMastoPublic(a)
		if err != nil {
			return nil, gtserror.NewErrorInternalError(err)
		}
		accounts = append(accounts, *account)
	}
	return accounts, nil
}

func (p *processor) AccountRelationshipGet(authed *oauth.Auth, targetAccountID string) (*apimodel.Relationship, gtserror.WithCode) {
	if authed == nil || authed.Account == nil {
		return nil, gtserror.NewErrorForbidden(errors.New("not authed"))
	}

	gtsR, err := p.db.GetRelationship(authed.Account.ID, targetAccountID)
	if err != nil {
		return nil, gtserror.NewErrorInternalError(fmt.Errorf("error getting relationship: %s", err))
	}

	r, err := p.tc.RelationshipToMasto(gtsR)
	if err != nil {
		return nil, gtserror.NewErrorInternalError(fmt.Errorf("error converting relationship: %s", err))
	}

	return r, nil
}

func (p *processor) AccountFollowCreate(authed *oauth.Auth, form *apimodel.AccountFollowRequest) (*apimodel.Relationship, gtserror.WithCode) {
	// if there's a block between the accounts we shouldn't create the request ofc
	blocked, err := p.db.Blocked(authed.Account.ID, form.TargetAccountID)
	if err != nil {
		return nil, gtserror.NewErrorInternalError(err)
	}
	if blocked {
		return nil, gtserror.NewErrorNotFound(fmt.Errorf("accountfollowcreate: block exists between accounts"))
	}

	// make sure the target account actually exists in our db
	targetAcct := &gtsmodel.Account{}
	if err := p.db.GetByID(form.TargetAccountID, targetAcct); err != nil {
		if _, ok := err.(db.ErrNoEntries); ok {
			return nil, gtserror.NewErrorNotFound(fmt.Errorf("accountfollowcreate: account %s not found in the db: %s", form.TargetAccountID, err))
		}
	}

	// check if a follow exists already
	follows, err := p.db.Follows(authed.Account, targetAcct)
	if err != nil {
		return nil, gtserror.NewErrorInternalError(fmt.Errorf("accountfollowcreate: error checking follow in db: %s", err))
	}
	if follows {
		// already follows so just return the relationship
		return p.AccountRelationshipGet(authed, form.TargetAccountID)
	}

	// check if a follow exists already
	followRequested, err := p.db.FollowRequested(authed.Account, targetAcct)
	if err != nil {
		return nil, gtserror.NewErrorInternalError(fmt.Errorf("accountfollowcreate: error checking follow request in db: %s", err))
	}
	if followRequested {
		// already follow requested so just return the relationship
		return p.AccountRelationshipGet(authed, form.TargetAccountID)
	}

	// make the follow request
	newFollowID, err := id.NewRandomULID()
	if err != nil {
		return nil, gtserror.NewErrorInternalError(err)
	}

	fr := &gtsmodel.FollowRequest{
		ID:              newFollowID,
		AccountID:       authed.Account.ID,
		TargetAccountID: form.TargetAccountID,
		ShowReblogs:     true,
		URI:             util.GenerateURIForFollow(authed.Account.Username, p.config.Protocol, p.config.Host, newFollowID),
		Notify:          false,
	}
	if form.Reblogs != nil {
		fr.ShowReblogs = *form.Reblogs
	}
	if form.Notify != nil {
		fr.Notify = *form.Notify
	}

	// whack it in the database
	if err := p.db.Put(fr); err != nil {
		return nil, gtserror.NewErrorInternalError(fmt.Errorf("accountfollowcreate: error creating follow request in db: %s", err))
	}

	// if it's a local account that's not locked we can just straight up accept the follow request
	if !targetAcct.Locked && targetAcct.Domain == "" {
		if _, err := p.db.AcceptFollowRequest(authed.Account.ID, form.TargetAccountID); err != nil {
			return nil, gtserror.NewErrorInternalError(fmt.Errorf("accountfollowcreate: error accepting folow request for local unlocked account: %s", err))
		}
		// return the new relationship
		return p.AccountRelationshipGet(authed, form.TargetAccountID)
	}

	// otherwise we leave the follow request as it is and we handle the rest of the process asynchronously
	p.fromClientAPI <- gtsmodel.FromClientAPI{
		APObjectType:   gtsmodel.ActivityStreamsFollow,
		APActivityType: gtsmodel.ActivityStreamsCreate,
		GTSModel:       fr,
		OriginAccount:  authed.Account,
		TargetAccount:  targetAcct,
	}

	// return whatever relationship results from this
	return p.AccountRelationshipGet(authed, form.TargetAccountID)
}

func (p *processor) AccountFollowRemove(authed *oauth.Auth, targetAccountID string) (*apimodel.Relationship, gtserror.WithCode) {
	// if there's a block between the accounts we shouldn't do anything
	blocked, err := p.db.Blocked(authed.Account.ID, targetAccountID)
	if err != nil {
		return nil, gtserror.NewErrorInternalError(err)
	}
	if blocked {
		return nil, gtserror.NewErrorNotFound(fmt.Errorf("AccountFollowRemove: block exists between accounts"))
	}

	// make sure the target account actually exists in our db
	targetAcct := &gtsmodel.Account{}
	if err := p.db.GetByID(targetAccountID, targetAcct); err != nil {
		if _, ok := err.(db.ErrNoEntries); ok {
			return nil, gtserror.NewErrorNotFound(fmt.Errorf("AccountFollowRemove: account %s not found in the db: %s", targetAccountID, err))
		}
	}

	// check if a follow request exists, and remove it if it does (storing the URI for later)
	var frChanged bool
	var frURI string
	fr := &gtsmodel.FollowRequest{}
	if err := p.db.GetWhere([]db.Where{
		{Key: "account_id", Value: authed.Account.ID},
		{Key: "target_account_id", Value: targetAccountID},
	}, fr); err == nil {
		frURI = fr.URI
		if err := p.db.DeleteByID(fr.ID, fr); err != nil {
			return nil, gtserror.NewErrorInternalError(fmt.Errorf("AccountFollowRemove: error removing follow request from db: %s", err))
		}
		frChanged = true
	}

	// now do the same thing for any existing follow
	var fChanged bool
	var fURI string
	f := &gtsmodel.Follow{}
	if err := p.db.GetWhere([]db.Where{
		{Key: "account_id", Value: authed.Account.ID},
		{Key: "target_account_id", Value: targetAccountID},
	}, f); err == nil {
		fURI = f.URI
		if err := p.db.DeleteByID(f.ID, f); err != nil {
			return nil, gtserror.NewErrorInternalError(fmt.Errorf("AccountFollowRemove: error removing follow from db: %s", err))
		}
		fChanged = true
	}

	// follow request status changed so send the UNDO activity to the channel for async processing
	if frChanged {
		p.fromClientAPI <- gtsmodel.FromClientAPI{
			APObjectType:   gtsmodel.ActivityStreamsFollow,
			APActivityType: gtsmodel.ActivityStreamsUndo,
			GTSModel: &gtsmodel.Follow{
				AccountID:       authed.Account.ID,
				TargetAccountID: targetAccountID,
				URI:             frURI,
			},
			OriginAccount: authed.Account,
			TargetAccount: targetAcct,
		}
	}

	// follow status changed so send the UNDO activity to the channel for async processing
	if fChanged {
		p.fromClientAPI <- gtsmodel.FromClientAPI{
			APObjectType:   gtsmodel.ActivityStreamsFollow,
			APActivityType: gtsmodel.ActivityStreamsUndo,
			GTSModel: &gtsmodel.Follow{
				AccountID:       authed.Account.ID,
				TargetAccountID: targetAccountID,
				URI:             fURI,
			},
			OriginAccount: authed.Account,
			TargetAccount: targetAcct,
		}
	}

	// return whatever relationship results from all this
	return p.AccountRelationshipGet(authed, targetAccountID)
}