<?php

declare(strict_types=1);

namespace Orrisroot;

class DigiTemp
{
    /**
     * @var string digitemp command path
     */
    private string $commandPath;

    /**
     * @var string config file path
     */
    private string $configPath;

    /**
     * @var array config data
     */
    private array $config = [
        'TTY' => '',
        'READ_TIME' => 0,
        'LOG_TYPE' => 0,
        'LOG_FORMAT' => '',
        'CNT_FORMAT' => '',
        'HUM_FORMAT' => '',
        'SENSORS' => 0,
        'ROM' => [],
    ];

    /**
     * constructor.
     *
     * @param string $commandPath digitemp command path
     * @param string $configPath  config file path
     */
    public function __construct(string $commandPath, string $configPath)
    {
        $this->commandPath = $commandPath;
        $this->configPath = $configPath;
        $this->parseConfig();
    }

    /**
     * get number of sensors.
     */
    public function getNumSensors(): int
    {
        return $this->config['SENSORS'];
    }

    /**
     * get sensor id.
     *
     * @param int $num sensor number
     *
     * @return ?string
     */
    public function getSensorId(int $num): ?string
    {
        return isset($this->config['ROM'][$num]) ? $this->config['ROM'][$num] : null;
    }

    /**
     * read sensor.
     *
     * @param int $num sensor number
     *
     * @return ?float
     */
    public function readSensor(int $num): ?float
    {
        $cmd = escapeshellcmd($this->commandPath.' -c '.$this->configPath.' -q -t '.$num.' -o"%.2C" 2>/dev/null');
        exec($cmd, $output, $ret);
        if (0 !== $ret) {
            return null;
        }

        return (float) $output[0];
    }

    /**
     * parse config file.
     *
     * @return false if failure
     */
    private function parseConfig(): bool
    {
        foreach (file($this->configPath) as $line) {
            preg_match_all('/"(?:\\\\.|[^\\\\"])*"|\S+/', trim($line), $matches);
            if (empty($matches[0])) {
                continue;
            }
            $cols = $matches[0];
            $key = array_shift($cols);
            $value = array_shift($cols);
            switch ($key) {
            case 'TTY':
                $this->config[$key] = $value;
                break;
            case 'READ_TIME':
                $this->config[$key] = (int) $value;
                break;
            case 'LOG_TYPE':
                $this->config[$key] = (int) $value;
                break;
            case 'LOG_FORMAT':
                $this->config[$key] = '"' === substr($value, 0, 1) ? stripslashes(substr($value, 1, -1)) : $value;
                break;
            case 'CNT_FORMAT':
                $this->config[$key] = '"' === substr($value, 0, 1) ? stripslashes(substr($value, 1, -1)) : $value;
                break;
            case 'HUM_FORMAT':
                $this->config[$key] = '"' === substr($value, 0, 1) ? stripslashes(substr($value, 1, -1)) : $value;
                break;
            case 'SENSORS':
                $this->config[$key] = (int) $value;
                break;
            case 'ROM':
                $this->config[$key][(int) $value] = str_replace('0x', '', implode('', array_reverse($cols)));
                break;
            default:
                return false;
            }
        }

        return true;
    }
}