<?php

namespace Model;

use PDO;

/**
 * Task model
 *
 * @package  model
 * @author   Frederic Guillot
 */
class Task extends Base
{
    /**
     * SQL table name
     *
     * @var string
     */
    const TABLE               = 'tasks';

    /**
     * Task status
     *
     * @var integer
     */
    const STATUS_OPEN         = 1;
    const STATUS_CLOSED       = 0;

    /**
     * Events
     *
     * @var string
     */
    const EVENT_MOVE_COLUMN     = 'task.move.column';
    const EVENT_MOVE_POSITION   = 'task.move.position';
    const EVENT_UPDATE          = 'task.update';
    const EVENT_CREATE          = 'task.create';
    const EVENT_CLOSE           = 'task.close';
    const EVENT_OPEN            = 'task.open';
    const EVENT_CREATE_UPDATE   = 'task.create_update';
    const EVENT_ASSIGNEE_CHANGE = 'task.assignee_change';

    /**
     * Get a list of due tasks for all projects
     *
     * @access public
     * @return array
     */
    public function getOverdueTasks()
    {
        $tasks = $this->db->table(self::TABLE)
                    ->columns(
                        self::TABLE.'.id',
                        self::TABLE.'.title',
                        self::TABLE.'.date_due',
                        self::TABLE.'.project_id',
                        Project::TABLE.'.name AS project_name',
                        User::TABLE.'.username AS assignee_username',
                        User::TABLE.'.name AS assignee_name'
                    )
                    ->join(Project::TABLE, 'id', 'project_id')
                    ->join(User::TABLE, 'id', 'owner_id')
                    ->eq(Project::TABLE.'.is_active', 1)
                    ->eq(self::TABLE.'.is_active', 1)
                    ->neq(self::TABLE.'.date_due', 0)
                    ->lte(self::TABLE.'.date_due', mktime(23, 59, 59))
                    ->findAll();

        return $tasks;
    }

    /**
     * Get task details (fetch more information from other tables)
     *
     * @access public
     * @param  integer   $task_id   Task id
     * @return array
     */
    public function getDetails($task_id)
    {
        $sql = '
            SELECT
            tasks.id,
            tasks.title,
            tasks.description,
            tasks.date_creation,
            tasks.date_completed,
            tasks.date_modification,
            tasks.date_due,
            tasks.color_id,
            tasks.project_id,
            tasks.column_id,
            tasks.owner_id,
            tasks.creator_id,
            tasks.position,
            tasks.is_active,
            tasks.score,
            tasks.category_id,
            project_has_categories.name AS category_name,
            projects.name AS project_name,
            columns.title AS column_title,
            users.username AS assignee_username,
            users.name AS assignee_name,
            creators.username AS creator_username,
            creators.name AS creator_name
            FROM tasks
            LEFT JOIN users ON users.id = tasks.owner_id
            LEFT JOIN users AS creators ON creators.id = tasks.creator_id
            LEFT JOIN project_has_categories ON project_has_categories.id = tasks.category_id
            LEFT JOIN projects ON projects.id = tasks.project_id
            LEFT JOIN columns ON columns.id = tasks.column_id
            WHERE tasks.id = ?
        ';

        $rq = $this->db->execute($sql, array($task_id));
        return $rq->fetch(PDO::FETCH_ASSOC);
    }

    /**
     * Fetch one task
     *
     * @access public
     * @param  integer   $task_id   Task id
     * @return array
     */
    public function getById($task_id)
    {
        return $this->db->table(self::TABLE)->eq('id', $task_id)->findOne();
    }

    /**
     * Count all tasks for a given project and status
     *
     * @access public
     * @param  integer   $project_id      Project id
     * @param  integer   $status_id       Status id
     * @return array
     */
    public function getAll($project_id, $status_id = self::STATUS_OPEN)
    {
        return $this->db
                    ->table(self::TABLE)
                    ->eq('project_id', $project_id)
                    ->eq('is_active', $status_id)
                    ->findAll();
    }

    /**
     * Count all tasks for a given project and status
     *
     * @access public
     * @param  integer   $project_id   Project id
     * @param  array     $status       List of status id
     * @return integer
     */
    public function countByProjectId($project_id, array $status = array(self::STATUS_OPEN, self::STATUS_CLOSED))
    {
        return $this->db
                    ->table(self::TABLE)
                    ->eq('project_id', $project_id)
                    ->in('is_active', $status)
                    ->count();
    }

    /**
     * Count the number of tasks for a given column and status
     *
     * @access public
     * @param  integer   $project_id   Project id
     * @param  integer   $column_id    Column id
     * @param  array     $status       List of status id
     * @return integer
     */
    public function countByColumnId($project_id, $column_id, array $status = array(self::STATUS_OPEN))
    {
        return $this->db
                    ->table(self::TABLE)
                    ->eq('project_id', $project_id)
                    ->eq('column_id', $column_id)
                    ->in('is_active', $status)
                    ->count();
    }

    /**
     * Get tasks that match defined filters
     *
     * @access public
     * @param  array    $filters   Filters: [ ['column' => '...', 'operator' => '...', 'value' => '...'], ... ]
     * @param  array    $sorting   Sorting: [ 'column' => 'date_creation', 'direction' => 'asc']
     * @return array
     */
    public function find(array $filters, array $sorting = array())
    {
        $table = $this->db
                    ->table(self::TABLE)
                    ->columns(
                        '(SELECT count(*) FROM comments WHERE task_id=tasks.id) AS nb_comments',
                        '(SELECT count(*) FROM task_has_files WHERE task_id=tasks.id) AS nb_files',
                        '(SELECT count(*) FROM task_has_subtasks WHERE task_id=tasks.id) AS nb_subtasks',
                        '(SELECT count(*) FROM task_has_subtasks WHERE task_id=tasks.id AND status=2) AS nb_completed_subtasks',
                        'tasks.id',
                        'tasks.title',
                        'tasks.description',
                        'tasks.date_creation',
                        'tasks.date_modification',
                        'tasks.date_completed',
                        'tasks.date_due',
                        'tasks.color_id',
                        'tasks.project_id',
                        'tasks.column_id',
                        'tasks.owner_id',
                        'tasks.creator_id',
                        'tasks.position',
                        'tasks.is_active',
                        'tasks.score',
                        'tasks.category_id',
                        'users.username AS assignee_username',
                        'users.name AS assignee_name'
                    )
                    ->join(User::TABLE, 'id', 'owner_id');

        foreach ($filters as $key => $filter) {

            if ($key === 'or') {

                $table->beginOr();

                foreach ($filter as $subfilter) {
                    $table->$subfilter['operator']($subfilter['column'], $subfilter['value']);
                }

                $table->closeOr();
            }
            else if (isset($filter['operator']) && isset($filter['column']) && isset($filter['value'])) {
                $table->$filter['operator']($filter['column'], $filter['value']);
            }
        }

        if (empty($sorting)) {
            $table->orderBy('tasks.position', 'ASC');
        }
        else {
            $table->orderBy($sorting['column'], $sorting['direction']);
        }

        return $table->findAll();
    }

    /**
     * Generic method to duplicate a task
     *
     * @access public
     * @param  array      $task         Task data
     * @param  array      $override     Task properties to override
     * @return integer|boolean
     */
    public function copy(array $task, array $override = array())
    {
        // Values to override
        if (! empty($override)) {
            $task = $override + $task;
        }

        $this->db->startTransaction();

        // Assign new values
        $values = array();
        $values['title'] = $task['title'];
        $values['description'] = $task['description'];
        $values['date_creation'] = time();
        $values['date_modification'] = $values['date_creation'];
        $values['date_due'] = $task['date_due'];
        $values['color_id'] = $task['color_id'];
        $values['project_id'] = $task['project_id'];
        $values['column_id'] = $task['column_id'];
        $values['owner_id'] = 0;
        $values['creator_id'] = $task['creator_id'];
        $values['position'] = $this->countByColumnId($values['project_id'], $values['column_id']) + 1;
        $values['score'] = $task['score'];
        $values['category_id'] = 0;

        // Check if the assigned user is allowed for the new project
        if ($task['owner_id'] && $this->projectPermission->isUserAllowed($values['project_id'], $task['owner_id'])) {
            $values['owner_id'] = $task['owner_id'];
        }

        // Check if the category exists
        if ($task['category_id'] && $this->category->exists($task['category_id'], $task['project_id'])) {
            $values['category_id'] = $task['category_id'];
        }

        // Save task
        if (! $this->db->table(self::TABLE)->save($values)) {
            $this->db->cancelTransaction();
            return false;
        }

        $task_id = $this->db->getConnection()->getLastId();

        // Duplicate subtasks
        if (! $this->subTask->duplicate($task['id'], $task_id)) {
            $this->db->cancelTransaction();
            return false;
        }

        $this->db->closeTransaction();

        // Trigger events
        $this->event->trigger(self::EVENT_CREATE_UPDATE, array('task_id' => $task_id) + $values);
        $this->event->trigger(self::EVENT_CREATE, array('task_id' => $task_id) + $values);

        return $task_id;
    }

    /**
     * Duplicate a task to the same project
     *
     * @access public
     * @param  array      $task         Task data
     * @return integer|boolean
     */
    public function duplicateSameProject($task)
    {
        return $this->copy($task);
    }

    /**
     * Duplicate a task to another project (always copy to the first column)
     *
     * @access public
     * @param  integer    $project_id   Destination project id
     * @param  array      $task         Task data
     * @return integer|boolean
     */
    public function duplicateToAnotherProject($project_id, array $task)
    {
        return $this->copy($task, array(
            'project_id' => $project_id,
            'column_id' => $this->board->getFirstColumn($project_id),
        ));
    }

    /**
     * Prepare data before task creation or modification
     *
     * @access public
     * @param  array    $values    Form values
     */
    public function prepare(array &$values)
    {
        if (! empty($values['date_due']) && ! is_numeric($values['date_due'])) {
            $values['date_due'] = $this->dateParser->getTimestamp($values['date_due']);
        }

        $this->removeFields($values, array('another_task', 'id'));
        $this->resetFields($values, array('date_due', 'score', 'category_id'));
        $this->convertIntegerFields($values, array('is_active'));
    }

    /**
     * Prepare data before task creation
     *
     * @access public
     * @param  array    $values    Form values
     */
    public function prepareCreation(array &$values)
    {
        $this->prepare($values);

        if (empty($values['column_id'])) {
            $values['column_id'] = $this->board->getFirstColumn($values['project_id']);
        }

        if (empty($values['color_id'])) {
            $colors = $this->color->getList();
            $values['color_id'] = key($colors);
        }

        $values['date_creation'] = time();
        $values['date_modification'] = $values['date_creation'];
        $values['position'] = $this->countByColumnId($values['project_id'], $values['column_id']) + 1;
    }

    /**
     * Prepare data before task modification
     *
     * @access public
     * @param  array    $values    Form values
     */
    public function prepareModification(array &$values)
    {
        $this->prepare($values);
        $values['date_modification'] = time();
    }

    /**
     * Create a task
     *
     * @access public
     * @param  array    $values   Form values
     * @return boolean|integer
     */
    public function create(array $values)
    {
        $this->db->startTransaction();

        $this->prepareCreation($values);

        if (! $this->db->table(self::TABLE)->save($values)) {
            $this->db->cancelTransaction();
            return false;
        }

        $task_id = $this->db->getConnection()->getLastId();

        $this->db->closeTransaction();

        // Trigger events
        $this->event->trigger(self::EVENT_CREATE_UPDATE, array('task_id' => $task_id) + $values);
        $this->event->trigger(self::EVENT_CREATE, array('task_id' => $task_id) + $values);

        return $task_id;
    }

    /**
     * Update a task
     *
     * @access public
     * @param  array    $values            Form values
     * @param  boolean  $trigger_Events    Trigger events
     * @return boolean
     */
    public function update(array $values, $trigger_events = true)
    {
        // Fetch original task
        $original_task = $this->getById($values['id']);

        if (! $original_task) {
            return false;
        }

        // Prepare data
        $updated_task = $values;
        $this->prepareModification($updated_task);

        $result = $this->db->table(self::TABLE)->eq('id', $values['id'])->update($updated_task);

        if ($result && $trigger_events) {
            $this->triggerUpdateEvents($original_task, $updated_task);
        }

        return true;
    }

    /**
     * Trigger events for task modification
     *
     * @access public
     * @param  array    $original_task    Original task data
     * @param  array    $updated_task     Updated task data
     */
    public function triggerUpdateEvents(array $original_task, array $updated_task)
    {
        $events = array();

        if (isset($updated_task['owner_id']) && $original_task['owner_id'] != $updated_task['owner_id']) {
            $events[] = self::EVENT_ASSIGNEE_CHANGE;
        }
        else if (isset($updated_task['column_id']) && $original_task['column_id'] != $updated_task['column_id']) {
            $events[] = self::EVENT_MOVE_COLUMN;
        }
        else if (isset($updated_task['position']) && $original_task['position'] != $updated_task['position']) {
            $events[] = self::EVENT_MOVE_POSITION;
        }
        else {
            $events[] = self::EVENT_CREATE_UPDATE;
            $events[] = self::EVENT_UPDATE;
        }

        $event_data = array_merge($original_task, $updated_task);
        $event_data['task_id'] = $original_task['id'];

        foreach ($events as $event) {
            $this->event->trigger($event, $event_data);
        }
    }

    /**
     * Return true if the project exists
     *
     * @access public
     * @param  integer    $task_id   Task id
     * @return boolean
     */
    public function exists($task_id)
    {
        return $this->db->table(self::TABLE)->eq('id', $task_id)->count() === 1;
    }

    /**
     * Mark a task closed
     *
     * @access public
     * @param  integer   $task_id   Task id
     * @return boolean
     */
    public function close($task_id)
    {
        if (! $this->exists($task_id)) {
            return false;
        }

        $result = $this->db
                        ->table(self::TABLE)
                        ->eq('id', $task_id)
                        ->update(array(
                            'is_active' => 0,
                            'date_completed' => time()
                        ));

        if ($result) {
            $this->event->trigger(self::EVENT_CLOSE, array('task_id' => $task_id) + $this->getById($task_id));
        }

        return $result;
    }

    /**
     * Mark a task open
     *
     * @access public
     * @param  integer   $task_id   Task id
     * @return boolean
     */
    public function open($task_id)
    {
        if (! $this->exists($task_id)) {
            return false;
        }

        $result = $this->db
                        ->table(self::TABLE)
                        ->eq('id', $task_id)
                        ->update(array(
                            'is_active' => 1,
                            'date_completed' => 0
                        ));

        if ($result) {
            $this->event->trigger(self::EVENT_OPEN, array('task_id' => $task_id) + $this->getById($task_id));
        }

        return $result;
    }

    /**
     * Remove a task
     *
     * @access public
     * @param  integer   $task_id   Task id
     * @return boolean
     */
    public function remove($task_id)
    {
        if (! $this->exists($task_id)) {
            return false;
        }

        $this->file->removeAll($task_id);

        return $this->db->table(self::TABLE)->eq('id', $task_id)->remove();
    }

    /**
     * Move a task to another column or to another position
     *
     * @access public
     * @param  integer    $project_id        Project id
     * @param  integer    $task_id           Task id
     * @param  integer    $column_id         Column id
     * @param  integer    $position          Position (must be >= 1)
     * @return boolean
     */
    public function movePosition($project_id, $task_id, $column_id, $position)
    {
        // The position can't be lower than 1
        if ($position < 1) {
            return false;
        }

        $board = $this->db->table(Board::TABLE)->eq('project_id', $project_id)->asc('position')->findAllByColumn('id');
        $columns = array();

        // Prepare the columns
        foreach ($board as $board_column_id) {

            $columns[$board_column_id] = $this->db->table(self::TABLE)
                          ->eq('is_active', 1)
                          ->eq('project_id', $project_id)
                          ->eq('column_id', $board_column_id)
                          ->neq('id', $task_id)
                          ->asc('position')
                          ->findAllByColumn('id');
        }

        // The column must exists
        if (! isset($columns[$column_id])) {
            return false;
        }

        // We put our task to the new position
        array_splice($columns[$column_id], $position - 1, 0, $task_id); // print_r($columns);

        // We save the new positions for all tasks
        return $this->savePositions($task_id, $columns);
    }

    /**
     * Save task positions
     *
     * @access private
     * @param  integer     $moved_task_id    Id of the moved task
     * @param  array       $columns          Sorted tasks
     * @return boolean
     */
    private function savePositions($moved_task_id, array $columns)
    {
        $this->db->startTransaction();

        foreach ($columns as $column_id => $column) {

            $position = 1;

            foreach ($column as $task_id) {

                if ($task_id == $moved_task_id) {

                    // Events will be triggered only for that task
                    $result = $this->update(array(
                        'id' => $task_id,
                        'position' => $position,
                        'column_id' => $column_id
                    ));
                }
                else {
                    $result = $this->db->table(self::TABLE)->eq('id', $task_id)->update(array(
                        'position' => $position,
                        'column_id' => $column_id
                    ));
                }

                $position++;

                if (! $result) {
                    $this->db->cancelTransaction();
                    return false;
                }
            }
        }

        $this->db->closeTransaction();

        return true;
    }

    /**
     * Move a task to another project
     *
     * @access public
     * @param  integer    $project_id           Project id
     * @param  array      $task                 Task data
     * @return boolean
     */
    public function moveToAnotherProject($project_id, array $task)
    {
        $values = array();

        // Clear values (categories are different for each project)
        $values['category_id'] = 0;
        $values['owner_id'] = 0;

        // Check if the assigned user is allowed for the new project
        if ($task['owner_id'] && $this->projectPermission->isUserAllowed($project_id, $task['owner_id'])) {
            $values['owner_id'] = $task['owner_id'];
        }

        // We use the first column of the new project
        $values['column_id'] = $this->board->getFirstColumn($project_id);
        $values['position'] = $this->countByColumnId($project_id, $values['column_id']) + 1;
        $values['project_id'] = $project_id;

        if ($this->db->table(self::TABLE)->eq('id', $task['id'])->update($values)) {
            return $task['id'];
        }

        return false;
    }
}