#!/usr/bin/php
<?php

$missing = <<<MISSING
  Config file not found (/etc/inno_backup.conf)

  Create a new file with the following keys/values:

  user = backups
  pass = password1234
  backup_dir = /backups
  data_dir = /var/lib/mysql
MISSING;

if( ! file_exists('/etc/inno_backup.conf') ) {
  exit($missing."\n");
}

$conf = parse_ini_file('/etc/inno_backup.conf');

$user       = $conf['user'];
$pass       = $conf['pass'];
$data_dir   = $conf['data_dir'];
$backup_dir = $conf['backup_dir'];

$usage = <<<USAGE
  USAGE: inno_backup [option]

  Options:
    full        : Start a full backup. This will delete ALL incrementals and the current full snapshot.
    incremental : Start an incremental. If no full backup exists, the script will fall back to a full backup.
    prepare     : Glues all incrementals to the full snapshot in preparation for a restore.
    restore     : Shuts down MySQL, removes content of datadir, replaces it with the backup. Dangerous.
    reset       : THIS WILL NUKE THE BACKUP DIRECTORY AND ALL CONTENT WITHIN! Only use to start clean.
USAGE;

$arg = ( isset($argv[1]) ) ? $argv[1] : "";

$base_args = "--user={$user} --password={$pass}";

switch( strtolower($arg) ) {
  case "full":
    full();
  break;

  case "incremental":
    incremental();
  break;

  case "prepare":
    prepare();
  break;

  case "restore":
    // This is dangerous, yo. Gotta think of a good way to fool-proof it.
    restore();
  break;

  case "reset":
    exec("rm -rf {$backup_dir}/logs/* {$backup_dir}/incremental/* {$backup_dir}/full/* {$backup_dir}/last_incremental");
    echo "Backup directory cleaned.\n";
  break;

  default:
    echo "No option supplied. See usage below:\n\n";
    echo $usage."\n";
    exit();
}

## Functions!

function full() {
  global $user, $pass, $backup_dir, $base_args;

  if( ! file_exists($backup_dir) ) {
    echo "Cannot find backup directory : {$backup_dir}\n";
    exit();
  }

  if( file_exists($backup_dir."/full") ) {
    echo "Found existing full backup directory. Removing it and all incrementals.\n";
    exec("rm -rf {$backup_dir}/full {$backup_dir}/incremental/* {$backup_dir}/last_incremental");
  }

  echo "Starting backup -- this takes an average of 3 to 3.5 hours.\n";
  exec("innobackupex {$base_args} --no-timestamp {$backup_dir}/full &>{$backup_dir}/logs/full.log");
  if( check_log($backup_dir."/logs/full.log") ) {
    echo "Backup complete.\n";
    exec("rm -f {$backup_dir}/logs/full.log");
  } else {
    echo "Backup failed. Review {$backup_dir}/logs/full.log\n";
  }
}

function incremental() {
  global $user, $pass, $backup_dir, $base_args;

  echo "Starting incremental backup.\n";
  echo "Checking for existing full backup.\n";
  if( ! file_exists($backup_dir."/full/xtrabackup_checkpoints") ) {
    echo "There is no full backup. Please execute: inno_backup full\n";
    exit();
  }
  echo "Found existing full backup. Kicking off incremental backup.\n";

  if( ! file_exists($backup_dir."/last_incremental") ) {
    $inc = 1;
    file_put_contents($backup_dir."/last_incremental", $inc);
  } else {
    echo "Found last_incremental file\n";
    $inc = (int) file_get_contents($backup_dir."/last_incremental");
    echo "Last incremental: #{$inc}\n";
    $inc++;
  }

  if( $inc == 1 ) {
    exec("innobackupex {$base_args} --no-timestamp --incremental {$backup_dir}/incremental/{$inc} --incremental-basedir={$backup_dir}/full &>{$backup_dir}/logs/incremental.log");
  } else {
    $inc_prev = $inc-1;
    exec("innobackupex {$base_args} --no-timestamp --incremental {$backup_dir}/incremental/{$inc} --incremental-basedir={$backup_dir}/incremental/{$inc_prev} &>{$backup_dir}/logs/incremental.log");
  }

  if( check_log($backup_dir."/logs/incremental.log") ) {
    echo "Incremental complete.\n";
    exec("rm -f {$backup_dir}/logs/incremental.log");
  } else {
    echo "Backup failed. Review {$backup_dir}/logs/incremental.log\n";
    exit();
  }

  file_put_contents($backup_dir."/last_incremental", $inc++);
}

function prepare() {
  global $user, $pass, $backup_dir, $base_args;

  if( ! file_exists($backup_dir."/last_incremental") ) {
    exit("Missing {$backup_dir}/last_incremental.\n");
  }

  echo "Rebuilding full backup from incrementals for restoration. This may take a while ...\n";
  $inc = (int) file_get_contents($backup_dir."/last_incremental");

  exec("innobackupex {$base_args} --no-timestamp --use-memory=500M --apply-log {$backup_dir}/full &>{$backup_dir}/logs/prepare.log");

  if( ! check_log($backup_dir."/logs/prepare.log") ) {
    echo "Failed to prepare backup for restoration. Check {$backup_dir}/logs/prepare.log\n";
    exit();
  }

  for($i = 1; $i <= $inc; $i++) {
    echo "Processing incremental: {$i}\n";
    exec("innobackupex {$base_args} --apply-log --redo-only --incremental /backups/full/ --incremental-basedir=/backups/incremental/{$i} &>{$backup_dir}/logs/prepare.log");
    if( ! check_log($backup_dir."/logs/prepare.log") ) {
      echo "Failed to apply incremental #{$i} to full backup. Check {$backup_dir}/logs/prepare.log\n";
      exit();
    }
  }

  echo "Final preparation running ...\n";

  exec("innobackupex {$base_args} --apply-log {$backup_dir}/full --use-memory=500M &>{$backup_dir}/logs/prepare.log");
  if( check_log($backup_dir."/logs/prepare.log") ) {
    echo "Preparation has completed successfully. You may now attempt: inno_backup restore\n";
  } else {
    exit("Final preparation has failed. Review {$backup_dir}/logs/prepare.log\n");
    exec("rm -rf {$backup_dir}/last_incremental {$backup_dir}/incremental/* {$backup_dir}/logs/prepare.log");

  }
}

function restore() {
  global $user, $pass, $backup_dir, $base_args;

  echo "This is a highly destructive process. Do not run this unless absolutely sure.\n";
  echo "Are you sure you want to run the restore process? (y/N): ";

  $handle = fopen("php://stdin", "r");
  $line = fgets($handle);
  if( strtolower(trim($line)) != 'y' ) {
    exit("Aborting. Good choice, mortal.\n");
  }

  echo "Just kidding. This isn't implemented yet, meat-bag.\n";

}

function check_log($file) {
  $res = exec("tail -n 1 {$file}");
  if( strstr($res, "OK!" ) ) {
    return true;
  }

  return false;
}