<?php

class Mapbox_StaticImageApi {

    public static function getImageFileContent(Array $params) : ?string {
        $access_token = $params["access_token"];
        $gps_lat = $params["gps_lat"];
        $gps_long = $params["gps_long"];
        $zoom = $params["zoom"];
        $size_x = $params["size_x"];
        $size_y = $params["size_y"];
        $style = $params["style"];
        $pin = $params["pin"];
        $paths = $params["paths"];

        $pin_part = "";

        // https://api.mapbox.com/styles/v1/mapbox/satellite-streets-v12/static/pin-l-embassy+ee9900(15.4200370610,46.9599897293)/15.4200370610,46.9599897293,19/640x640?access_token=pk.eyJ1Ijoic2tuZXR3b3J4IiwiYSI6ImNqdWw3eXoyMzBieWU0M284OTU2eWNxMTMifQ.GrgBYKMXVt3TiwU53OBllQ
        $url = "https://api.mapbox.com/styles/v1/mapbox/$style/static";
        if(is_array($pin) && $pin["gps_lat"] && $pin["gps_long"] && $pin["size"]) {
            $pin_gps_lat = $pin["gps_lat"];
            $pin_gps_long = $pin["gps_long"];
            $pin_size = $pin["size"];
            $pin_color = $pin["color"];
            $pin_icon = $pin["icon"];

            $pin_part .= "pin-$pin_size";
            if($pin_icon) $pin_part .= "-$pin_icon";
            $pin_part .= "+$pin_color($pin_gps_long,$pin_gps_lat)";
        }

        $path_parts = [];
        if(is_array($paths) && count($paths)) {
            $path_stroke_width = $paths["line_width"];
            $path_stroke_color = $paths["line_color"];
            $path_stroke_opacity = $paths["line_opacity"];
            $path_fill_color = $paths["line_fill_color"];
            $path_fill_opacity = $paths["line_fill_opacity"];

            foreach($paths["coords"] as $path) {
                if(!is_array($path)) {
                    mfLoghandler::singleton()->debug("path not array: ".print_r($path, true));
                    continue;
                }

                $path_enc_polyline = self::encodeCoordArrayToPolyline($path);
                if(!$path_enc_polyline) continue;

                $path_parts[] = "path-$path_stroke_width+$path_stroke_color-$path_stroke_opacity+$path_fill_color-$path_fill_opacity($path_enc_polyline)";
            }
        }

        // build url
        $url_opt_parts = [];
        if($pin_part) $url_opt_parts[] = $pin_part;

        if(count($path_parts)) {
            foreach($path_parts as $path_part) {
                $url_opt_parts[] = $path_part;
            }
        }

        if(is_array($url_opt_parts)) {
            $url .= "/".implode(",", $url_opt_parts);
        }

        $url .= "/auto/{$size_x}x{$size_y}?access_token=$access_token";

        mfLoghandler::singleton()->debug($url);
        //exit;

        $ctx_opts = [
            'http' => [
                'method' => 'GET',
                'header' => 'accept: application/json'
            ]
        ];

        $ctx = stream_context_create($ctx_opts);
        $response = file_get_contents($url, false, $ctx);

        if($response === false) {
            return null;
        }

        return $response;

    }

    public static function encodeCoordArrayToPolyline($coords, $precision = 5) {
        //if(!is_array($coords)) return false;

        $points = [];
        array_walk_recursive(
            $coords,
            function ($current) use (&$points) {
                $points[] = $current;
            }
        );

        mfLoghandler::singleton()->debug(__METHOD__.": flattened path: ".print_r($points, true));

        $encodedString = '';
        $index = 0;
        $previous = array(0,0);
        foreach ( $points as $number ) {
            $number = (float)($number);
            $number = (int)round($number * pow(10, $precision));
            $diff = $number - $previous[$index % 2];
            $previous[$index % 2] = $number;
            $number = $diff;
            $index++;
            $number = ($number < 0) ? ~($number << 1) : ($number << 1);
            $chunk = '';
            while ( $number >= 0x20 ) {
                $chunk .= chr((0x20 | ($number & 0x1f)) + 63);
                $number >>= 5;
            }
            $chunk .= chr($number + 63);
            $encodedString .= $chunk;
        }

        mfLoghandler::singleton()->debug(__METHOD__.": encoded polyline: $encodedString");


        return str_replace("?", "%3f", $encodedString);
    }
}