Output bugs to bug report file

Load common-settings.php and get 3 x querystring params, exploding first
2 into arrays
$result is OK to start with, but if we have a file that's not available,
set it to error
If we don't have an error, the seen sizes aren't null and the seen and
actual sizes don't match, we need to get bug lines
Set $result to bugs and some vars to begin with
fseek, ftell and while loop to get chunks of content using pointer
movement methods. We also reduce $chars and $lines here to escape the
while loop as required
$output has line endings converted and trimmed, before exploding on new
lines and only getting last few lines, stitched back together with
imploder
The bug report is written, $tmpLoc established and all data put into the
$status array to feed back in the XHR response

lib/bug-files-check.php

@@ -1,30 +1,93 @@
 <?php
-// TO DO:
+// Load common functions
+include("settings-common.php");
 
-// After setting 3 new bug file params in settings, open dev console to see the URL that's being called
+$files		= explode(",",str_replace("|","/",$_GET['files']));
+$filesSizesSeen	= explode(",",$_GET['filesSizesSeen']);
+$maxLines	= $_GET['maxLines'];
 
-// This file will be called upon by XHR, on the timer value specified (eg 2 secs), with 3 querystring keys - files, filesMDTs and maxLines
-// eg: bug-files-check.php?files=|var|domain|log.txt,|var|domain|another|example.txt&filesMDTs=123456,123478&maxLines=100
+$result = "ok";
 
-// You can then grab the list of files and MDTs (modified datetimes) from the querystring into 2 PHP arrays
+for ($i=0; $i<count($files); $i++) {
+	$files[$i] = $_SERVER['DOCUMENT_ROOT'].$files[$i];
+	$filesSizesSeen[$i] = filesize($files[$i]);
+	if (!file_exists($files[$i])) {
+		$result = "error";
+	}
+}
 
-// The first time this file is run, there will be no MDTs in top.ICEcoder.openFileMDTs, so the querysting will contain filesMDTs=null,null
-// If there are null MDTs, get the files MDT (eg using filemtime($file) on Linux) for each file and push into the array at top.ICEcoder.openFileMDTs
+if ($result != "error") {
 
-// The 2nd and all subsequent time this file runs, we'll of course have MDTs in that JS array and that's what gets passed in the querysting from then on
-// From the 2nd call onwards, we can compare the querystring MDT against the actual file MDT and if different, we need to get results as there's new bugs
+	// If we have a value here, we can test, otherwise don't
+	if (explode(",",$_GET['filesSizesSeen'])[0]!="null" && explode(",",$_GET['filesSizesSeen'])[0] != $filesSizesSeen[0]) {
+		$result = "bugs";
 
-// So at that point, we can get the maxLines value from the querystring, tail that number of lines from the file in question into tmp/bug-report.log
+		$filename = $files[0];
+		$chars = ($filesSizesSeen[0]-explode(",",$_GET['filesSizesSeen'])[0]);
+		$buffer = 4096;
+		$lines = $maxLines+1+1; // 1 (possibly) for end of file and 1 for partial lines
 
-// After all of this, we can set $result to one of 4 states - off, error, ok or bugs
-// You can change the value below now to see the icon change
+		// Open the file
+		$f = fopen($filename, "rb");
 
+		// Jump to last character
+		fseek($f, 0, SEEK_END);
 
+		if(fread($f, 1) != "\n") $lines -= 1;
 
+		// Start reading
+		$output = "";
+		$chunk = "";
+
+		// While we would like more
+		while(ftell($f) > 0 && $chars > 0 && $lines > 0) {
+
+			// Figure out how far back we should jump
+			$seek = min($chars, $buffer);
+
+			// Do the jump (backwards, relative to where we are)
+			fseek($f, -$seek, SEEK_CUR);
+
+			// Read a chunk and prepend it to our output
+			$output = ($chunk = fread($f, $seek)).$output;
+
+			// Jump back to where we started reading
+			fseek($f, -mb_strlen($chunk, '8bit'), SEEK_CUR);
+
+			// Take this seek chunk off the number of chars
+			$chars -= $seek;
+
+			$lines -= substr_count($chunk, "\n");	
+		}
+
+		// Close file
+		fclose($f); 
+
+		$output = rtrim(str_replace("\r\n","\n",$output));
+		$output = explode("\n",$output);
+		$output = array_slice($output, -$maxLines);
+		$output = implode("\n",$output);
+
+		file_put_contents("../tmp/bug-report.log", $output);
+	}
+
+}
+
+$tmpLoc = dirname(__FILE__);
+$tmpLoc = explode(DIRECTORY_SEPARATOR,$tmpLoc);
+$tmpLoc = $tmpLoc[count($tmpLoc)-2];
 
 // Output result and status array
-$result = "off";
-$status = array("result" => $result);
+$status = array(
+	"files" => $files,
+	"filesSizesSeen" => $filesSizesSeen,
+	"maxLines" => $maxLines,
+	"chars" => (isset($chars) ? $chars : null),
+	"lines" => substr_count($output, "\n"),
+	"seek" => (isset($seek) ? $seek : null),
+	"bugReportPath" => "|".$tmpLoc."|tmp|bug-report.log",
+	"result" => $result
+);
 
 // Include our process once our bug checking work is done
 include("../processes/on-bug-check.php");