<?php

namespace Kanboard\Plugin\QualKard\Helper;

use Kanboard\Core\Base;

/**
 * QualKard helper: the qualcard grading math (ported from Ruben's C program) plus the per-board gates.
 *
 * Scores per grade column: hairy=0.0, hard=1.3, medium=3.0, easy=5.0. The running average is
 * M1 = (M0 + N)/2, with a new (unread) card seeded at N - 23%. The average maps to a review interval
 * (qualcard grades G..A, 1..11 days). qualcard's H/same-day and the overdue decay are intentionally
 * NOT ported: there is no "again now", and the Study column is itself the overdue backlog.
 */
class QualKardHelper extends Base
{
    const SCORE = array('hairy' => 0.0, 'hard' => 1.3, 'medium' => 3.0, 'easy' => 5.0);

    /**
     * Running average. New card (unread, $old === null) seeds at N - 23%; otherwise the qualcard mean.
     */
    public static function nextAverage($old, $score)
    {
        return $old === null ? ($score - 0.23 * $score) : (($old + $score) / 2.0);
    }

    /**
     * Average -> review interval in days (qualcard grades G..A).
     */
    public static function intervalDays($avg)
    {
        if ($avg <= 0.60) {
            return 1; // G
        }
        if ($avg <= 1.35) {
            return 2; // F
        }
        if ($avg <= 2.20) {
            return 3; // E
        }
        if ($avg <= 3.05) {
            return 5; // D
        }
        if ($avg <= 3.90) {
            return 7; // C
        }
        if ($avg <= 4.92) {
            return 9; // B
        }

        return 11; // A
    }

    /**
     * Next due timestamp: midnight, intervalDays() out.
     */
    public static function dueFrom($avg, $now = null)
    {
        $now = $now ?: time();

        return strtotime('+'.self::intervalDays($avg).' days', strtotime('today', $now));
    }

    /**
     * Mastery badge for a card's average: label + CSS class. null (unread) = "new" (yellow); otherwise
     * a percent of 5, coloured red (<50) / green (<90) / blue (>=90).
     *
     * @param  float|null $avg
     * @return array{label:string,class:string}
     */
    public static function badge($avg)
    {
        if ($avg === null) {
            return array('label' => t('new'), 'class' => 'qk-new');
        }

        $pct = (int) round($avg / 5.0 * 100);
        $class = $pct < 50 ? 'qk-low' : ($pct < 90 ? 'qk-mid' : 'qk-high');

        return array('label' => $pct.'%', 'class' => $class);
    }

    /**
     * Is QualKard enabled for this board?
     *
     * @param  int $project_id
     * @return bool
     */
    public function isEnabled($project_id)
    {
        return (int) $this->projectMetadataModel->get($project_id, 'qualkard_enabled', 0) === 1;
    }

    /**
     * Is the RecoReco plugin installed? (QualKard needs its move engine.)
     *
     * @return bool
     */
    public function hasRecoReco()
    {
        foreach ($this->container['pluginLoader']->getPlugins() as $plugin) {
            if ($plugin->getPluginName() === 'RecoReco') {
                return true;
            }
        }

        return false;
    }

    /**
     * The column id stored for a board role ('draft', 'study', 'hairy', ... , 'done').
     *
     * @param  int    $project_id
     * @param  string $role
     * @return int
     */
    public function col($project_id, $role)
    {
        return (int) $this->projectMetadataModel->get($project_id, 'qualkard_col_'.$role, 0);
    }
}