<?php if( !defined('__ROOT__') ) define('__ROOT__', dirname(dirname(__FILE__)) );

	require_once 'Builder.php';


	class Exporter{

		private $packages; // will contain packages (config)

		public static function config_path(){ return __ROOT__.'/exporter/packages.json'; }


		/* CONSTRUCTOR -> LOADS CONFIG
		*
		*/
		public function __construct(){

			$this->packages = json_decode( file_get_contents(self::config_path()), true);

		}


		/* REMOVES ENABLED MODULES
		*
		*/
		public function init(){
			$this->packages['installed'] = [];
			$this->store();

			return true;
		}

		/* RETURNS AVAILABLE MODULE LIST
		*
		* @return packages<Array> 							Set containing packages and their versions
		*
		*/
		public function available(){
			$packages = [];

			foreach($this->packages['available'] as $package=>$versions){
				$packages[$package] = [];

				foreach($versions as $version=>$dependencies)
					// if version of package enabled
					if( isset($this->packages['installed'][$package]) && $version == $this->packages['installed'][$package] )
						$packages[$package][] = [ 'version' => $version, 'enabled' => true ];
					else
						$packages[$package][] = [ 'version' => $version, 'enabled' => false ];
			}

			return $packages;
		}


		/* ENABLES A MODULE'S VERSION
		*
		* @pPackage<String> 										Package's name
		* @pVersion<String> 									Package's version
		* @pDep<Boolean> 										dependency level
		*
		* @return err_msg<String>								Error message | TRUE (if all is ok)
		*
		*/
		public function install($pPackage=null, $pVersion=null, $pDep=0){

			/* [1] Package management
			=========================================================*/
			/* (1) If @package not given, exit */
			if( is_null($pPackage) )
				return "Missing @packageName.\n";

			/* (2) Checking package existence */
			if( !isset($this->packages['available'][$pPackage]) )
				return "Package `$pPackage` unknown.\n";

			/* (3) Set package name & content */
			$mname        = $pPackage;
			$package      = $this->packages['available'][$mname];


			/* [2] Version management
			=========================================================*/
			/* (1) Set default latest version name & content */
			$vname        = array_slice( array_keys($package), -1 )[0];
			$dependencies = $package[$vname];
			$flag = '#latest';

			/* (2) Existing version set it */
			if( !is_null($pVersion) && isset($package[$pVersion]) ){
				$dependencies = $package[( $vname = $pVersion )];
				$flag         = '';
			}


			/* [3] Enables package & version
			=========================================================*/
			/* (1) If package disabled -> enables it */
			if( !isset($this->packages['installed'][$mname]) )
				$this->packages['installed'][$mname] = '0';

			/* (2) Checks cross version dependency -> if another installed package needs another version */
			foreach($this->packages['installed'] as $xPackage=>$xVersion){

				// {2.1} Loads each installed package's dependencies //
				$xDependencies = $this->getDependencies($xPackage,$xVersion);

				// if not found -> next
				if(	$xDependencies === false )
					continue;

				// {2.2} if package can't have version of current package //
				if(	isset($xDependencies[$mname]) && !in_array($vname, $xDependencies[$mname]) )
					return str_repeat("  ", $pDep)."$xPackage:$xVersion doesn't support $mname:$vname\n\n** aborted **\n";

			}


			/* (5) If no conflict -> set version */
			echo str_repeat("  ", $pDep)."[$mname:$vname]   $flag\n";

			// in any case -> store new package's version
			$this->packages['installed'][$mname] = $vname;

			/* [4] Loading dependencies
			=========================================================*/
			/* (1) Loading each dependency */
			if( count($dependencies) > 0 ){

				foreach($dependencies as $depMod=>$depVersions){

					// Only load last version
					foreach($depVersions as $version)
						$installed = $this->install($depMod, $version, $pDep+1);

					// error propagation
					if(	$installed !== true )
						return $installed;
				}
			}


			/* [5] Storing data
			=========================================================*/
			$this->store();

			return true;
		}


		/* DISABLES A MODULE'S VERSION
		*
		* @pPackage<String> 									Package's name
		*
		* @return err_msg<String> 							Error message || TRUE if success
		*
		*/
		public function remove($pPackage=null){
			/* [1] Package management (existence)
			=========================================================*/
			/* (1) If @package not given, exit */
			if( is_null($pPackage) )
				return "Missing @packageName.\n";

			/* (2) Checking if package is enabled */
			$enabled_packages = array_keys($this->packages['installed']);
			if( !in_array($pPackage, $enabled_packages) )
				return "Package `$pPackage` not enabled.\n";

			/* (3) Set package name & content */
			$mname  = $pPackage;
			$package = $this->packages['installed'][$mname];


			/* [2] Dependency verification (not needed)
			=========================================================*/
			$dependency = false; // if it's a dependency of another enabled package
			$callers = [];       // list of enabled packages that needs current one

			/* (1) For each enabled package (excepted itself) */
			foreach($enabled_packages as $package){

				// except current package
				if( $package == $mname ) continue;

				/* (2) For each version of its package (and its dependencies) */
				foreach($this->packages['available'][$package] as $version=>$dependencies){

					// if not the current enabled package's version
					if( $version != $this->packages['installed'][$package] )
						continue;

					/* (3) If current package in dependencies -> can't disable */
					isset($dependencies[$mname]) && ($dependency = true) && ($callers[] = "`$package`");

				}

			}

			/* (4) If a dependency, explain */
			if( $dependency )
				return "Cannot disable package $mname because ".implode(',',$callers)." needs it.\n";


			/* [3] Disabling package
			=========================================================*/
			/* (1) Disabling package */
			unset($this->packages['installed'][$mname]);

			/* (2) Storing changes */
			$this->store();

			/* (3) Return success */
			return true;
		}


		/* BUILDS A PROJECT
		*
		* @pPath<String> 										Path to project root
		*
		*/
		public function build($pPath){
			$builder = new Builder($pPath, $this->packages['installed']);

			$builder->build();
		}


		/* RETURNS THE LIST OF THE DEPENDENCIES OF A MODULE
		*
		* @package<String> 										Package's label
		* @version<String> 										Package's version
		*
		* @return dependencies<Array> 							List of dependencies
		*														FALSE if error
		*
		*/
		private function getDependencies($package=null, $version=null){
			/* [1] Search for package
			=========================================================*/
			/* (1) Checks package */
			if(	!isset($this->packages['available'][$package]) )
				return false;

			/* (2) Checks version */
			if(	!isset($this->packages['available'][$package][$version]) )
				return false;

			/* [2] Returns dependencies
			=========================================================*/
			/* (1) If not an array */
			if(	!is_array($this->packages['available'][$package][$version]) )
				return [];

			/* (2) If all right */
			return $this->packages['available'][$package][$version];
		}


		/* STORES DATA
		*
		*/
		public function store(){
			file_put_contents(self::config_path(), json_encode($this->packages, JSON_PRETTY_PRINT));
		}

	}

?>