<?php

namespace App\Helpers;

use DateTime;

class TimeLine {

    public $start = null;
    public $end = null;
    public $available = [];
    public $unavailable = [];

    public $removeStart = null;
    public $removeEnd = null;

    public function __construct(DateTime $_start, DateTime $_end)
    {
        $this->start = $_start->getTimestamp();
        $this->end = $_end->getTimestamp();
    }

    public function addAvailability(DateTime $_start, DateTime $_end) {

        $this->available[] = new TimeSlot($_start, $_end);

        // sort by start
        usort($this->available, function ($item1, $item2) {
            return $item1->start <=> $item2->start;
        });

        // compact (join adjacent overlapping slots)
        // $this->vdump($this->available);
        $this->normalize();
        $this->vdump($this->available);
    }

    public function removeAvailability(DateTime $_start, DateTime $_end) {

        $this->removeStart = $_start->getTimestamp();
        $this->removeEnd = $_end->getTimestamp();

        $this->cleanRemove();

        $removeStart = null;
        $removeSnd = null;

        // sort by start
        usort($this->available, function ($item1, $item2) {
            return $item1->start <=> $item2->start;
        });
        $this->normalize();
        $this->vdump($this->available);
    }

    private function cleanRemove() {

        $allDone = true;

        for ($i=0; $i<count($this->available); $i++) {

            // removeStart at or after slot start
            // removeEnd at or before slot end
            // split slot into 2
            if($this->removeStart >= $this->available[$i]->start &&
                $this->removeEnd <= $this->available[$i]->end) {
                $newSlot = new TimeSlot(new DateTime(), new DateTime());
                $newSlot->start = $this->removeEnd;
                $newSlot->end = $this->available[$i]->end;

                $this->available[$i]->end = $this->removeStart;
                array_splice($this->available, $i+1, 0, [$newSlot]);
                $allDone = true;
                break;
            }

            // removeStart at or after slot start
            // removeStart at or before slot end
            // update slot to end at removeStart
            if($this->removeStart >= $this->available[$i]->start &&
                $this->removeStart <= $this->available[$i]->end) {
                $this->available[$i]->end = $this->removeStart;
                $allDone = false;
                break;
            }

            // process removeEnd

            // removeEnd at or after slot start
            // removeEnd at or before slot end
            // update slot to start at removeEnd
            if($this->removeEnd >= $this->available[$i]->start &&
                $this->removeEnd <= $this->available[$i]->end) {
                $this->available[$i]->start = $this->removeEnd;
                $allDone = false;
                break;
            }

        }

        if(!$allDone) {
            $this->normalize(); // recurse till clean
        }
    }

    private function normalize() {

        $allDone = true;

        for ($i=0; $i<count($this->available)-1; $i++) {
            if($this->available[$i]->end >= $this->available[$i+1]->start && // ends in the middle of next slot
                $this->available[$i]->end <= $this->available[$i+1]->end)
            {
                // extend self & delete next
                $this->available[$i]->end = $this->available[$i+1]->end;
                array_splice($this->available, $i+1, 1);
                $allDone = false;
                break;
            }

            if($this->available[$i]->end >= $this->available[$i+1]->end) // ends after next slot end
            {
                // delete next
                array_splice($this->available, $i+1, 1);
                $allDone = false;
                break;
            }

            if($this->available[$i]->start >= $this->available[$i]->end) // starts and ends at the same time!
            {
                // delete self
                array_splice($this->available, $i, 1);
                $allDone = false;
                break;
            }
        }

        if(!$allDone) {
            $this->normalize(); // recurse till clean
        }

    }

    public function vdump($_x) {
//        echo "<pre>";
//        print_r($_x);
//        echo "</pre><hr>";
    }

}