From a4ea061f389e8e1dfdd61e1e668f6b8a6d2dae4e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Nicol=C3=B2=20P=2E?= <nicolo.paraciani@cnr.it>
Date: Tue, 24 Sep 2024 23:03:36 +0200
Subject: [PATCH] Initial commit

---
 .gitignore                              |  2 +
 composer.json                           | 25 +++++++++
 src/Exceptions/InvalidFitsException.php | 10 ++++
 src/Exceptions/InvalidPathException.php | 12 ++++
 src/Fits.php                            | 73 +++++++++++++++++++++++++
 src/FitsHeader.php                      | 10 ++++
 6 files changed, 132 insertions(+)
 create mode 100644 .gitignore
 create mode 100644 composer.json
 create mode 100644 src/Exceptions/InvalidFitsException.php
 create mode 100644 src/Exceptions/InvalidPathException.php
 create mode 100644 src/Fits.php
 create mode 100644 src/FitsHeader.php

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..d8a7996
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+composer.lock
+vendor/
diff --git a/composer.json b/composer.json
new file mode 100644
index 0000000..c9ed08c
--- /dev/null
+++ b/composer.json
@@ -0,0 +1,25 @@
+{
+    "name": "dumbastro/fits-php",
+    "description": "A crappy and dumb FITS library for PHP to (possibly?) interact with astronomical images",
+    "type": "library",
+    "version": "0.1",
+    "require": {
+        "psr/log": "^3.0"
+    },
+    "require-dev": {
+        "phpstan/phpstan": "^1.12",
+        "friendsofphp/php-cs-fixer": "^3.64",
+        "symfony/var-dumper": "^7.1",
+        "phpunit/phpunit": "^11.3"
+    },
+    "scripts": {
+        "run-pstan": "vendor/bin/phpstan analyze src/ --level 6"
+    },
+    "license": "MIT",
+    "autoload": {
+        "psr-4": {
+            "Dumbastro\\FitsPhp\\": "src/"
+        }
+    },
+    "minimum-stability": "beta"
+}
diff --git a/src/Exceptions/InvalidFitsException.php b/src/Exceptions/InvalidFitsException.php
new file mode 100644
index 0000000..55a287b
--- /dev/null
+++ b/src/Exceptions/InvalidFitsException.php
@@ -0,0 +1,10 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Dumbastro\FitsPhp\Exceptions;
+
+final class InvalidFitsException extends \Exception implements \Throwable
+{
+}
+
diff --git a/src/Exceptions/InvalidPathException.php b/src/Exceptions/InvalidPathException.php
new file mode 100644
index 0000000..8563a0f
--- /dev/null
+++ b/src/Exceptions/InvalidPathException.php
@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Dumbastro\FitsPhp\Exceptions;
+
+/**
+* @todo Different exception if path is not writable?
+*/
+final class InvalidPathException extends \Exception
+{
+}
diff --git a/src/Fits.php b/src/Fits.php
new file mode 100644
index 0000000..d9a2f8d
--- /dev/null
+++ b/src/Fits.php
@@ -0,0 +1,73 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Dumbastro\FitsPhp;
+
+use Dumbastro\FitsPhp\Exceptions\{
+    InvalidFitsException,
+    InvalidPathException,
+};
+
+class Fits
+{
+    /**
+    * @var resource $byteStream
+    */
+    private $byteStream;
+    private string $path;
+    public readonly int $size;
+
+    /**
+    * @throws InvalidFitsException, InvalidPathException
+    * @todo Check path for reading/writing errors
+    */
+    public function __construct(string $path)
+    {
+        if (! is_readable($path) || ! is_file($path)) {
+            throw new InvalidPathException("The path '$path' is not readable or is not a file.");
+        }
+        $this->byteStream = fopen($path, 'rb');
+        $this->path = $path;
+        $this->size = filesize($this->path);
+
+        if (! $this->validate()) {
+            throw new InvalidFitsException('The opened file is not a valid FITS image (invalid block size)');
+        }
+    }
+    /**
+    * Validate the given FITS file based on block sizes
+    *
+    * From the FITS standard spec: 
+    *   > "Each FITS structure shall consist of an integral number of
+    *    FITS blocks, which are each 2880 bytes (23040 bits) in length."
+    *   (_Definition of the Flexible Image Transport System (FITS)_, ch. 3, par. 3.1)
+    */
+    public function validate(): bool
+    {
+        if ($this->size % 2880 !== 0) {
+            return false;
+        }
+
+        return true;
+    }
+    /**
+    * @todo Return FitsHeader object
+    * @return string
+    */
+    #[\ReturnTypeWillChange]
+    public function header(): string
+    {
+        $contents = fread($this->byteStream, $this->size);
+        $end = strpos($contents, 'END');
+        // Determine minimum integer number of blocks including 'END' position
+        $headerEnd = (($end - ($end % 2880)) / 2880 + 1) * 2880;
+
+        return substr($contents, 0, $headerEnd);
+    }
+
+    public function fromPath(string $path): void
+    {
+        $this->byteStream = fopen($path, 'rb');
+    }
+}
diff --git a/src/FitsHeader.php b/src/FitsHeader.php
new file mode 100644
index 0000000..068256f
--- /dev/null
+++ b/src/FitsHeader.php
@@ -0,0 +1,10 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Dumbastro\FitsPhp;
+
+class FitsHeader
+{
+}
+