<?php
require_once($CFG->libdir.'/gradelib.php');
require_once($CFG->dirroot.'/grade/querylib.php');

//namespace block_gradelevel;

class block_gradelevel_levelset {
	const UNDEFINED_BADGE_COLOR="#3F3F3F";
	const NULL_BADGE_COLOR = "000000";
	const DEFAULT_ICON = "/blocks/gradelevel/pix/undefinedskill.svg";
	
	const GLOBAL_DEFAULTS = array(
			0 => "#320000",	
			250 => "#2ad4ff",	// + 250
			750 => "#cd7f32",	// + 500
			1750 => "#92A1A6",  // + 1000
			2750 => "#f6ae00",  // + 2000
		);

	private $id;
	private $data;
	private $levels = null;
	private $global_levels = null;
	
	/**
	 * Construct a levelset object for an existing database item
	 * 
	 */
	private function __construct($id = null, $dataObject = null)
	{
		global $DB;

		$this->id = $id;
		if($id != null)
		{
			if(isset($dataObject) && isset($dataObject->id) && $dataObject->id == $id) // slight sanity check
			{
				$this->data = $dataObject;
			}
			else {
				// database validity check went south, retrieve again
				$this->data = $DB->get_record('block_gradelevel_levelset', array('id' => $this->id));
			}

			//retrieve levels for this levelset
			$this->levels = $DB->get_records('block_gradelevel_levels', array('levelset_id' => $this->id));

			usort( $this->levels, function( $a, $b) {
				return ( $a->points < $b->points ) ? -1 : 1;
			} );

		}
		// retrieve global levels
		$this->global_levels = $DB->get_records('block_gradelevel_levels', array('levelset_id' => 0));

		usort( $this->global_levels, function( $a, $b) {
			return ( $a->points < $b->points ) ? -1 : 1;
		} );

		// if no global levels are defined, insert default global levels
		if(count($this->global_levels) == 0)
		{
			foreach(static::GLOBAL_DEFAULTS as $points => $color)
			{
				// setup default
				$row = new stdClass;
				$row->levelset_id = 0;
				$row->points = $points;
				$row->badgecolor = $color;
				// insert into db
				if(!$DB->insert_record('block_gradelevel_levels',$row)){
					print_error('inserterror', 'block_gradelevel');
				}
			
			}

			// and reload global levels;
			$this->global_levels = $DB->get_records('block_gradelevel_levels', array('levelset_id' => 0));

			usort( $this->global_levels, function( $a, $b) {
				return ( $a->points < $b->points ) ? -1 : 1;
			} );

		}

	}

	public function getId() : string
	{
		return $this->id;
	}

	public function setName(string $name)
	{
		$this->data->name = $name;
	}

	public function getName() : string
	{
		return $this->data->name;
	}

	public function setIcon(string $iconname)
	{
		$this->data->icon = $iconname;
	}

	public function getIcon() : string
	{
		$icon = $this->data->icon;
		if(empty($icon))
		{
			$icon = static::DEFAULT_ICON;
		}
		return $icon;
	}



	/**
	 * Find a levelset for a given course
	 * 
	 * @params int $course_id The id of the course to find a levelset for
	 * @return levelset The levelset for this course or null if none found;
	 */
	static public function find_by_course($course_id)
	{
		global $DB;

		try {
			// FIXME: Make this more efficient by joining it into one sql statement.
			$records = $DB->get_records('block_gradelevel_course_link', array('course_id' => $course_id));
			if(count($records) > 0)
			{
				$levelset = $DB->get_record('block_gradelevel_levelset', array('id' => array_values($records)[0]->levelset_id));
				if($levelset)
				{
					return new static($levelset->id,$levelset);
				}
			}
		}
		catch(Exception $x){} // catch error if table does not (yet exist)
		return null; // return null if no current levelset linked
	}

	static public function find_by_id(int $id)
	{
		global $DB;
		
		$levelset = $DB->get_record('block_gradelevel_levelset', array('id' => $id));
		if($levelset)
		{
			return new static($levelset->id,$levelset);
		}	
		else
		{
			return null;	
		}

	}

	/**
	 * List attached courses for this levelset
	 * 
	 * @return array An array with the id's of attached courses
	 */
	public function list_courses()
	{
		global $DB;
		$list = array();
		$links = $DB->get_records('block_gradelevel_course_link', array('levelset_id' => $this->id));
		foreach($links as $link)
		{
			$list[] = $link->course_id;
		}

		return $list;
	}

	/**
	 * Attach a course to this levelset. The course will be detached from any other levelsets.
	 * 
	 * @params int $course_id The id of the course to attach
	 */
	public function attach_course($course_id)
	{
		global $DB;
		// check if course attachement is already done
		if(!in_array($course_id,$this->list_courses))
		{
			// no, now find an existing attachment for this course
			$rows = $DB->get_records('block_gradelevel_course_link', array('course_id' => $course_id));
			if(empty($rows))
			{
				// create new attachment if existing link was not found
				$row = new stdClass;
				$row->levelset_id = $this->id;
				$row->course_id = $course_id;
				// insert new row
				if(!$DB->insert_record('block_gradelevel_course_link',$row)){
					print_error('inserterror', 'block_gradelevel');
				}
			}
			else 
			{
				// update existing link (automatically detaches course from its previous levelset)
				$row = array_values($rows)[0];
				
				$row->course_id = $course_id;
				// update existing row
				if(!$DB->update_record('block_gradelevel_course_link',$row)){
					print_error('updateerror', 'block_gradelevel');
				}
			}
		}

	}

	/**
	 * Detache a course from this levelset. 
	 * 
	 * @params int $course_id The id of the course to detach
	 */
	public function detach_course($course_id)
	{
		global $DB;
		$rows = $DB->get_records('block_gradelevel_course_link', array('course_id' => $course_id, 'levelset_id' => $this->id));
		if(!empty($rows))
		{
			if(!$DB->delete_records('block_gradelevel_course_link', array('id' => array_values($rows)[0]->id)))
			{
				print_error('deleteerror','block_gradelevel');
			}
		}
	}


	/**
	 * Store changes made to the levelset data parameter containing levelset data
	 * 
	 */	
	public function save_data()
	{
		global $DB;
		if($this->data->id == $this->id) // sanity check so we don't kill everything
		{
			if(!$DB->update_record('block_gradelevel_levelset',$this->data)){
				print_error('updateerror', 'block_gradelevel');
			}
		}
		else 
		{
			print_error('datarowchanged_error', 'block_gradelevel');
		}
	
	}

	/**
	 * Retrieve point total for all attached courses for a given user
	 * 
	 * @param int $user_id The id 
	 * @return int Total points for this user in this levelset
	 */
	public function get_levelset_grade($user_id)
	{
		// loop through all attached courses and add up the grade points gathered
		$points = 0;
		foreach($this->list_courses() as $course_id)
		{
			$result = grade_get_course_grade($user_id,$course_id);
			$points += $result->grade;
		}
		return $points;
	}

	/**
	 * Return the levelup data for a given userid in this levelset
	 * 
	 * @param int $user_id The id 
	 * @return stdClass A stdClass containing the level data for the specified number of point
	 */
	public function get_user_leveldata($user_id)
	{
		$points = $this->get_levelset_grade($user_id);
		return $this->calculate_level($points);
	}



	/**
	 * Create a new levelset
	 * 
	 * @params string $name Optional name of the new levelset
	 * @return levelset The new levelset
	 */
	static public function create_new($name="New levelset")
	{
		global $DB;
		// create a new levelset

		$row = new stdClass;
		$row->name = $name;

		if(!$id = $DB->insert_record('block_gradelevel_levelset',$row, true)){
			print_error('inserterror', 'block_gradelevel');
		}
		else 
		{
			$rows = $DB->get_records('block_gradelevel_levelset', array('id' => $id));
			if(count($rows) > 0)
			{
				return new static($id,array_values($rows)[0]);
			}
		}
		
		throw new RuntimeException("Could not create new levelset");
	}

	/**
	 * List all levelsets
	 * 
	 * @return array Array of levelset
	 */
	static public function list_all()
	{
		global $DB;
		$list = array();
		$levelsets = $DB->get_records('block_gradelevel_levelset');

		foreach($levelsets as $lset)
		{
			$list[] = new static($lset->id,$lset);
		}

		return $list;

	}

	/**
	 * Calculate the levelup data, given a specified set of points
	 * 
	 * @params int points The amount of points to  calculate for
	 * @return stdClass A stdClass containing the level data for the specified number of point
	 */
	public function calculate_level($points){

		$levels = $this->badgelevels();

		$level = -1;
		$badge_color = static::NULL_BADGE_COLOR;
		$current_at = 0;
		$next_at = 0;
		foreach($levels as $threshold => $badgeColor)
		{
			if($points >= $threshold){
				$level++;
				$badge_color = $badgeColor;
				$current_at = $threshold;
			}
			else 
			{
				$next_at = $threshold;
				break;
			}
		}

		$levelup_points = $next_at - $current_at;
		$points_in_level = $points - $current_at;
		if($levelup_points <= 0){ // at max level
			$progress = 0;
			$points_in_level = 0;
		}
		else 
		{
			$progress = $points_in_level / $levelup_points;
		}

		$result = new stdClass;
		$result->level = $level;
		$result->badge_color = $badge_color;
		$result->progress = $progress;
		$result->next_at = round($next_at);
		$result->levelup_total = round($levelup_points);
		$result->points_in_level = round($points_in_level);
		return $result;	
	}

	/**
	 * Simplified list of levels and associated badge colors for this levelset
	 * Takes data from global levelset if more specialized data is not set
	 * 
	 * @return array An array of points (keys) and badge color (values), sorted by level
	 */
	public function badgelevels()
	{

		$level_info = array();

		// If we have levels defined, use those, otherwise use the global levels
		if(!empty($this->levels))
		{
			if(array_values($this->levels)[0]->points > 0)
			{
				// insert level 0
				$level_info[0] = static::NULL_BADGE_COLOR;
			}

			$i = 0;
			foreach($this->levels as $lvl)
			{
				// Check if color is properly set or needs to be retrieved from global config
				if(!empty($lvl->badgecolor)) {
					$color = $lvl->badgecolor;
				}
				else 
				{
					$color = static::UNDEFINED_BADGE_COLOR;
				}

				$level_info[$lvl->points] = $color;
				$i++;
			}

		}
		else 
		{
			if(empty($this->global_levels) || array_values($this->global_levels)[0]->points > 0)
			{
				// insert level 1 if levels don't start at 0 points,
				// or if no global levels are defined. - At least start somewhere...
				$level_info[0] = static::NULL_BADGE_COLOR;
			}

			// use global levels if levelset is not defined.
			foreach($this->global_levels as $lvl)
			{
				// Check if color is properly set
				if(!empty($lvl->badgecolor)) {
					$color = $lvl->badgecolor;
				}
				else 
				{
					$color = static::UNDEFINED_BADGE_COLOR;
				}
				$level_info[$lvl->points] = $color;
			}
		}

		return $level_info;

	}

	public function render_badge(int $points,int $size=150){
		global $CFG;
		
		$info = $this->calculate_level($points);

		$image = $this->getIcon();
		if(strncmp($image,"data:",5) == 0)
		{
			$image_url = $CFG->wwwroot."/blocks/gradelevel/view-icon.php?skillid=".$this->id;
		}
		else 
		{
			$image_url = $image;
		}

        $html  = "<figure class='levelbadge weird'";
		$html .= " data-color='{$info->badge_color}'";
		$html .= " data-progress='{$info->progress}'";
		$html .= " data-level='{$info->level}'";
		$html .= " data-width='{$size}'";
		$html .= " data-height='{$size}'";
		$html .= ">";
		if(!empty($image))
		{
			$html .= "<img style='display:none' src='{$image_url}' />";
		}
		$html .= "</figure>";
		return $html;        
    }

	public function render_demo_badge(int $size=100, $level=null)
	{
		$levels = $this->badgelevels();
		if($level == null || $level > count($levels))
		{
			$points = array_pop(array_keys($levels));
		}
		else
		{
			$points = array_keys($levels)[$level];
		}
	
		return $this->render_badge($points, $size);

	}

}