// Copyright 2018-2020 Vikunja and contriubtors. All rights reserved.
//
// This file is part of Vikunja.
//
// Vikunja is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Vikunja 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 General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Vikunja.  If not, see <https://www.gnu.org/licenses/>.

package models

import (
	"code.vikunja.io/api/pkg/user"
	"code.vikunja.io/web"
	"time"
)

// TaskCollection is a struct used to hold filter details and not clutter the Task struct with information not related to actual tasks.
type TaskCollection struct {
	ListID            int64 `param:"list"`
	StartDateSortUnix int64 `query:"startdate"`
	EndDateSortUnix   int64 `query:"enddate"`
	Lists             []*List

	// The query parameter to sort by. This is for ex. done, priority, etc.
	SortBy    []string `query:"sort_by"`
	SortByArr []string `query:"sort_by[]"`
	// The query parameter to order the items by. This can be either asc or desc, with asc being the default.
	OrderBy    []string `query:"order_by"`
	OrderByArr []string `query:"order_by[]"`

	web.CRUDable `xorm:"-" json:"-"`
	web.Rights   `xorm:"-" json:"-"`
}

// ReadAll gets all tasks for a collection
// @Summary Get tasks in a list
// @Description Returns all tasks for the current list.
// @tags task
// @Accept json
// @Produce json
// @Param listID path int true "The list ID."
// @Param page query int false "The page number. Used for pagination. If not provided, the first page of results is returned."
// @Param per_page query int false "The maximum number of items per page. Note this parameter is limited by the configured maximum of items per page."
// @Param s query string false "Search tasks by task text."
// @Param sort_by query string false "The sorting parameter. You can pass this multiple times to get the tasks ordered by multiple different parametes, along with `order_by`. Possible values to sort by are `id`, `text`, `description`, `done`, `done_at_unix`, `due_date_unix`, `created_by_id`, `list_id`, `repeat_after`, `priority`, `start_date_unix`, `end_date_unix`, `hex_color`, `percent_done`, `uid`, `created`, `updated`. Default is `id`."
// @Param order_by query string false "The ordering parameter. Possible values to order by are `asc` or `desc`. Default is `asc`."
// @Param startdate query int false "The start date parameter to filter by. Expects a unix timestamp. If no end date, but a start date is specified, the end date is set to the current time."
// @Param enddate query int false "The end date parameter to filter by. Expects a unix timestamp. If no start date, but an end date is specified, the start date is set to the current time."
// @Security JWTKeyAuth
// @Success 200 {array} models.Task "The tasks"
// @Failure 500 {object} models.Message "Internal error"
// @Router /lists/{listID}/tasks [get]
func (tf *TaskCollection) ReadAll(a web.Auth, search string, page int, perPage int) (result interface{}, resultCount int, totalItems int64, err error) {

	if len(tf.SortByArr) > 0 {
		tf.SortBy = append(tf.SortBy, tf.SortByArr...)
	}

	if len(tf.OrderByArr) > 0 {
		tf.OrderBy = append(tf.OrderBy, tf.OrderByArr...)
	}

	var sort = make([]*sortParam, 0, len(tf.SortBy))
	for i, s := range tf.SortBy {
		param := &sortParam{
			sortBy:  sortProperty(s),
			orderBy: orderAscending,
		}
		// This checks if tf.OrderBy has an entry with the same index as the current entry from tf.SortBy
		// Taken from https://stackoverflow.com/a/27252199/10924593
		if len(tf.OrderBy) > i {
			param.orderBy = getSortOrderFromString(tf.OrderBy[i])
		}
		// Param validation
		if err := param.validate(); err != nil {
			return nil, 0, 0, err
		}
		sort = append(sort, param)
	}

	taskopts := &taskOptions{
		search:    search,
		startDate: time.Unix(tf.StartDateSortUnix, 0),
		endDate:   time.Unix(tf.EndDateSortUnix, 0),
		page:      page,
		perPage:   perPage,
		sortby:    sort,
	}

	shareAuth, is := a.(*LinkSharing)
	if is {
		list := &List{ID: shareAuth.ListID}
		err := list.GetSimpleByID()
		if err != nil {
			return nil, 0, 0, err
		}
		return getTasksForLists([]*List{list}, taskopts)
	}

	// If the list ID is not set, we get all tasks for the user.
	// This allows to use this function in Task.ReadAll with a possibility to deprecate the latter at some point.
	if tf.ListID == 0 {
		tf.Lists, _, _, err = getRawListsForUser("", &user.User{ID: a.GetID()}, -1, 0)
		if err != nil {
			return nil, 0, 0, err
		}
	} else {
		// Check the list exists and the user has acess on it
		list := &List{ID: tf.ListID}
		canRead, err := list.CanRead(a)
		if err != nil {
			return nil, 0, 0, err
		}
		if !canRead {
			return nil, 0, 0, ErrUserDoesNotHaveAccessToList{ListID: tf.ListID}
		}
		tf.Lists = []*List{{ID: tf.ListID}}
	}

	return getTasksForLists(tf.Lists, taskopts)
}