<?php
// ProcessStream.php
// Created: 2023-01-25
// Updated: 2023-01-25

namespace Index\IO;

class ProcessStream extends Stream {
    private $handle;
    private bool $canRead;
    private bool $canWrite;

    public function __construct(string $command, string $mode) {
        $this->handle = popen($command, $mode);
        $this->canRead = strpos($mode, 'r') !== false;
        $this->canWrite = strpos($mode, 'w') !== false;

        if(!is_resource($this->handle))
            throw new IOException('Failed to create process.');
    }

    public function getPosition(): int {
        return -1;
    }

    public function getLength(): int {
        return -1;
    }
    public function setLength(int $length): void {}

    public function canRead(): bool {
        return $this->canRead;
    }

    public function canWrite(): bool {
        return $this->canWrite;
    }

    public function canSeek(): bool {
        return false;
    }

    public function hasTimedOut(): bool {
        return false;
    }

    public function isBlocking(): bool {
        return true;
    }

    public function isEnded(): bool {
        return feof($this->handle);
    }

    public function readChar(): ?string {
        $char = fgetc($this->handle);
        if($char === false)
            return null;
        return $char;
    }

    public function readLine(): ?string {
        return ($line = fgets($this->handle)) === false
            ? null : $line;
    }

    public function read(int $length): ?string {
        $buffer = fread($this->handle, $length);
        if($buffer === false)
            return null;
        return $buffer;
    }

    public function seek(int $offset, int $origin = self::START): int {
        throw new IOException('Cannot seek ProcessStream.');
    }

    public function write(string $buffer, int $length = -1): void {
        if($length >= 0)
            fwrite($this->handle, $buffer, $length);
        else
            fwrite($this->handle, $buffer);
    }

    public function writeChar(string $char): void {
        fwrite($this->handle, $char, 1);
    }

    public function flush(): void {}

    public function close(): void {
        if(is_resource($this->handle)) {
            pclose($this->handle);
            $this->handle = null;
        }
    }
}