// GoToSocial
// Copyright (C) GoToSocial Authors admin@gotosocial.org
// SPDX-License-Identifier: AGPL-3.0-or-later
//
// 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 accounts

import (
	"errors"
	"fmt"
	"net/http"
	"slices"
	"strconv"

	"github.com/gin-gonic/gin"
	"github.com/gin-gonic/gin/binding"
	"github.com/go-playground/form/v4"
	apimodel "github.com/superseriousbusiness/gotosocial/internal/api/model"
	apiutil "github.com/superseriousbusiness/gotosocial/internal/api/util"
	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
	"github.com/superseriousbusiness/gotosocial/internal/oauth"
)

// AccountUpdateCredentialsPATCHHandler swagger:operation PATCH /api/v1/accounts/update_credentials accountUpdate
//
// Update your account.
//
//	---
//	tags:
//	- accounts
//
//	consumes:
//	- multipart/form-data
//	- application/x-www-form-urlencoded
//	- application/json
//
//	produces:
//	- application/json
//
//	parameters:
//	-
//		name: discoverable
//		in: formData
//		description: Account should be made discoverable and shown in the profile directory (if enabled).
//		type: boolean
//	-
//		name: bot
//		in: formData
//		description: Account is flagged as a bot.
//		type: boolean
//	-
//		name: display_name
//		in: formData
//		description: The display name to use for the account.
//		type: string
//		allowEmptyValue: true
//	-
//		name: note
//		in: formData
//		description: Bio/description of this account.
//		type: string
//		allowEmptyValue: true
//	-
//		name: avatar
//		in: formData
//		description: Avatar of the user.
//		type: file
//	-
//		name: header
//		in: formData
//		description: Header of the user.
//		type: file
//	-
//		name: locked
//		in: formData
//		description: Require manual approval of follow requests.
//		type: boolean
//	-
//		name: source[privacy]
//		in: formData
//		description: Default post privacy for authored statuses.
//		type: string
//	-
//		name: source[sensitive]
//		in: formData
//		description: Mark authored statuses as sensitive by default.
//		type: boolean
//	-
//		name: source[language]
//		in: formData
//		description: Default language to use for authored statuses (ISO 6391).
//		type: string
//	-
//		name: source[status_content_type]
//		in: formData
//		description: Default content type to use for authored statuses (text/plain or text/markdown).
//		type: string
//	-
//		name: custom_css
//		in: formData
//		description: >-
//			Custom CSS to use when rendering this account's profile or statuses.
//			String must be no more than 5,000 characters (~5kb).
//		type: string
//	-
//		name: enable_rss
//		in: formData
//		description: Enable RSS feed for this account's Public posts at `/[username]/feed.rss`
//		type: boolean
//	-
//		name: fields_attributes[0][name]
//		in: formData
//		description: Name of 1st profile field to be added to this account's profile.
//			(The index may be any string; add more indexes to send more fields.)
//		type: string
//	-
//		name: fields_attributes[0][value]
//		in: formData
//		description: Value of 1st profile field to be added to this account's profile.
//			(The index may be any string; add more indexes to send more fields.)
//		type: string
//	-
//		name: fields_attributes[1][name]
//		in: formData
//		description: Name of 2nd profile field to be added to this account's profile.
//		type: string
//	-
//		name: fields_attributes[1][value]
//		in: formData
//		description: Value of 2nd profile field to be added to this account's profile.
//		type: string
//	-
//		name: fields_attributes[2][name]
//		in: formData
//		description: Name of 3rd profile field to be added to this account's profile.
//		type: string
//	-
//		name: fields_attributes[2][value]
//		in: formData
//		description: Value of 3rd profile field to be added to this account's profile.
//		type: string
//	-
//		name: fields_attributes[3][name]
//		in: formData
//		description: Name of 4th profile field to be added to this account's profile.
//		type: string
//	-
//		name: fields_attributes[3][value]
//		in: formData
//		description: Value of 4th profile field to be added to this account's profile.
//		type: string
//	-
//		name: fields_attributes[4][name]
//		in: formData
//		description: Name of 5th profile field to be added to this account's profile.
//		type: string
//	-
//		name: fields_attributes[4][value]
//		in: formData
//		description: Value of 5th profile field to be added to this account's profile.
//		type: string
//	-
//		name: fields_attributes[5][name]
//		in: formData
//		description: Name of 6th profile field to be added to this account's profile.
//		type: string
//	-
//		name: fields_attributes[5][value]
//		in: formData
//		description: Value of 6th profile field to be added to this account's profile.
//		type: string
//
//	security:
//	- OAuth2 Bearer:
//		- write:accounts
//
//	responses:
//		'200':
//			description: "The newly updated account."
//			schema:
//				"$ref": "#/definitions/account"
//		'400':
//			description: bad request
//		'401':
//			description: unauthorized
//		'404':
//			description: not found
//		'406':
//			description: not acceptable
//		'500':
//			description: internal server error
func (m *Module) AccountUpdateCredentialsPATCHHandler(c *gin.Context) {
	authed, err := oauth.Authed(c, true, true, true, true)
	if err != nil {
		apiutil.ErrorHandler(c, gtserror.NewErrorUnauthorized(err, err.Error()), m.processor.InstanceGetV1)
		return
	}

	if _, err := apiutil.NegotiateAccept(c, apiutil.JSONAcceptHeaders...); err != nil {
		apiutil.ErrorHandler(c, gtserror.NewErrorNotAcceptable(err, err.Error()), m.processor.InstanceGetV1)
		return
	}

	form, err := parseUpdateAccountForm(c)
	if err != nil {
		apiutil.ErrorHandler(c, gtserror.NewErrorBadRequest(err, err.Error()), m.processor.InstanceGetV1)
		return
	}

	acctSensitive, errWithCode := m.processor.Account().Update(c.Request.Context(), authed.Account, form)
	if errWithCode != nil {
		apiutil.ErrorHandler(c, errWithCode, m.processor.InstanceGetV1)
		return
	}

	apiutil.JSON(c, http.StatusOK, acctSensitive)
}

// fieldsAttributesFormBinding satisfies gin's binding.Binding interface.
// Should only be used specifically for multipart/form-data MIME type.
type fieldsAttributesFormBinding struct{}

func (fieldsAttributesFormBinding) Name() string {
	return "FieldsAttributes"
}

func (fieldsAttributesFormBinding) Bind(req *http.Request, obj any) error {
	if err := req.ParseForm(); err != nil {
		return err
	}

	// Change default namespace prefix and suffix to
	// allow correct parsing of the field attributes.
	decoder := form.NewDecoder()
	decoder.SetNamespacePrefix("[")
	decoder.SetNamespaceSuffix("]")

	return decoder.Decode(obj, req.Form)
}

func parseUpdateAccountForm(c *gin.Context) (*apimodel.UpdateCredentialsRequest, error) {
	form := &apimodel.UpdateCredentialsRequest{
		Source: &apimodel.UpdateSource{},
	}

	switch ct := c.ContentType(); ct {
	case binding.MIMEJSON:
		// Bind with default json binding first.
		if err := c.ShouldBindWith(form, binding.JSON); err != nil {
			return nil, err
		}

		// Now use custom form binding for
		// field attributes in the json data.
		var err error
		form.FieldsAttributes, err = parseFieldsAttributesFromJSON(form.JSONFieldsAttributes)
		if err != nil {
			return nil, fmt.Errorf("custom json binding failed: %w", err)
		}
	case binding.MIMEPOSTForm:
		// Bind with default form binding first.
		if err := c.ShouldBindWith(form, binding.FormPost); err != nil {
			return nil, err
		}

		// Now use custom form binding for
		// field attributes in the form data.
		if err := c.ShouldBindWith(form, fieldsAttributesFormBinding{}); err != nil {
			return nil, fmt.Errorf("custom form binding failed: %w", err)
		}
	case binding.MIMEMultipartPOSTForm:
		// Bind with default form binding first.
		if err := c.ShouldBindWith(form, binding.FormMultipart); err != nil {
			return nil, err
		}

		// Now use custom form binding for
		// field attributes in the form data.
		if err := c.ShouldBindWith(form, fieldsAttributesFormBinding{}); err != nil {
			return nil, fmt.Errorf("custom form binding failed: %w", err)
		}
	default:
		err := fmt.Errorf("content-type %s not supported for this endpoint; supported content-types are %s, %s, %s", ct, binding.MIMEJSON, binding.MIMEPOSTForm, binding.MIMEMultipartPOSTForm)
		return nil, err
	}

	if form == nil ||
		(form.Discoverable == nil &&
			form.Bot == nil &&
			form.DisplayName == nil &&
			form.Note == nil &&
			form.Avatar == nil &&
			form.Header == nil &&
			form.Locked == nil &&
			form.Source.Privacy == nil &&
			form.Source.Sensitive == nil &&
			form.Source.Language == nil &&
			form.Source.StatusContentType == nil &&
			form.FieldsAttributes == nil &&
			form.CustomCSS == nil &&
			form.EnableRSS == nil) {
		return nil, errors.New("empty form submitted")
	}

	return form, nil
}

func parseFieldsAttributesFromJSON(jsonFieldsAttributes *map[string]apimodel.UpdateField) (*[]apimodel.UpdateField, error) {
	if jsonFieldsAttributes == nil {
		// Nothing set, nothing to do.
		return nil, nil
	}

	fieldsAttributes := make([]apimodel.UpdateField, 0, len(*jsonFieldsAttributes))
	for keyStr, updateField := range *jsonFieldsAttributes {
		key, err := strconv.Atoi(keyStr)
		if err != nil {
			return nil, fmt.Errorf("couldn't parse fieldAttributes key %s to int: %w", keyStr, err)
		}

		fieldsAttributes = append(fieldsAttributes, apimodel.UpdateField{
			Key:   key,
			Name:  updateField.Name,
			Value: updateField.Value,
		})
	}

	// Sort slice by the key each field was submitted with.
	slices.SortFunc(fieldsAttributes, func(a, b apimodel.UpdateField) int {
		const k = +1
		switch {
		case a.Key > b.Key:
			return +k
		case a.Key < b.Key:
			return -k
		default:
			return 0
		}
	})

	return &fieldsAttributes, nil
}