<?php

namespace CorpusParole\Http\Controllers\Api;

// use CorpusParole\Http\Requests;

use Illuminate\Http\Request;

use Log;

use CorpusParole\Libraries\Sparql\SparqlClient;

use CorpusParole\Http\Controllers\Controller;

class DateStatsController extends Controller

{

    private $sparqlClient = null;

    public function __construct(SparqlClient $sparqlClient) {

        $this->sparqlClient = $sparqlClient;

    }

    /**

     * Display the specified resource.

     *

     * @return \Illuminate\Http\Response

     */

    public function index(Request $request)

    {

        $query =  preg_replace('/\s+/', ' ', "SELECT (?d as ?date) (COUNT(?d) AS ?count)

            WHERE {

                ?_ a <http://www.europeana.eu/schemas/edm/ProvidedCHO>.

                ?_ <http://purl.org/dc/terms/created> ?d

            }

            GROUP BY ?d

            ORDER BY ?d");

        $res = $this->sparqlClient->query($query);

        $dates = [];

        foreach ($res as $row) {

            $count = intval($row->count->getValue());

            $date = $row->date;

            $dateType = $date->getDatatypeUri();

            $processedDates = [];

            if($dateType === "http://purl.org/dc/terms/Period") {

                $processedDates = $this->processPeriod($date->getValue(), $count);

            }

            elseif($dateType === "http://purl.org/dc/terms/W3CDTF") {

                $processedDates = $this->processDate($date->getValue(), $count);

            }

            $dates = array_reduce(array_keys($processedDates), function($datesArray, $item) use ($processedDates) {

                if(!isset($datesArray[$item])) {

                    $datesArray[$item] = 0;

                }

                $datesArray[$item] += $processedDates[$item];

                return $datesArray;

            }, $dates);

        }

        ksort($dates);

        return response()->json(['datestats' => $dates ]);

    }

    private function extractYear($dateStr) {

        if(preg_match("/^\\d{4}$/", $dateStr) === 1) {

            $dateStr = "$dateStr-1-1";

        }

        $date = date_create($dateStr);

        if($date === false ) {

            Log::warning("DateStatsController:extractYear bad format for date $dateStr");

        }

        return $date?$date->format("Y"):false;

    }

    private function processPeriod($periodStr, $count) {

        $start = null;

        $end = null;

        foreach(explode(";", $periodStr) as $elem) {

            $elem = trim($elem);

            if(strpos($elem, 'start=') === 0) {

                $start = intval($this->extractYear(trim(substr($elem, 6))));

                if($start === false) {

                    return [];

                }

            } elseif(strpos($elem, 'end=') === 0) {

                $end = intval($this->extractYear(trim(substr($elem, 4))));

                if($end === false) {

                    return [];

                }

            }

        }

        if(is_null($start) || is_null($end) || $start>$end ) {

            // TODO: log problem

            return [];

        }

        $res = [];

        $mean = (int)($count/($end+1-$start));

        $remains = $count%($end+1-$start);

        for($d=$start; $d<=$end; $d++) {

            $nb = $mean + ((($remains--)>0)?1:0);

            if($nb !== 0) {

                $res[strval($d)] = $nb;

            }

        }

        return $res;

    }

    private function processDate($dateStr, $count) {

        $date = $this->extractYear($dateStr);

        if($date === false)  {

            return [];

        } else {

            return [ $this->extractYear($dateStr) => $count ];

        }

    }

}