(function() {    
    function injectScript(src, where) {
        var elm = document.createElement('script');
        elm.src = src;
        document[where || 'head'].appendChild(elm);
    }

    var customjs = localStorage['customjs'];
    if( customjs ) {
        try {
            customjs = JSON.parse(customjs);            
        }
        catch(e) { 
            // Backward compatibility (version >1)
            customjs = {
                source: customjs,
                config: {
                    enable: true,
                    include: '',
                    extra: ''
                }
            };
            localStorage['customjs'] = JSON.stringify(customjs);
        }        
        
        if( customjs.config.enable ) {

            // Predefined include
            if( customjs.config.include ) {
                injectScript('https://ajax.googleapis.com/ajax/libs' + customjs.config.include);
            }

            // Extra include 
            var extra = (customjs.config.extra || '').split(';');
            extra.forEach(function(line) {
                if( line.substr(0, 1) !== '#' ) {
                    injectScript(line);
                }
            });

            // Script
            if( customjs.source || customjs.src ) { 
                setTimeout(function() {
                    // Backward compatibility (version 1)
                    if( customjs.src ) {
                        customjs.source = 'data:text/javascript,' + customjs.src;
                    }
                    
                    injectScript(customjs.source, 'body');
                }, 250);
            }

        }
    }


    chrome.extension.onRequest.addListener(function(request, sender, sendResponse) {
    	switch(request.method) {
            case 'getHost':
                sendResponse({host: location.host});
                break;
    		case 'setCustomJS':
    			localStorage['customjs'] = JSON.stringify(request.customjs);
    		case 'getCustomJS':         
                var customjs = JSON.parse(localStorage['customjs'] || '{}');
    			sendResponse({customjs: customjs});
    			break;
    		case 'removeCustomJS':
    			delete localStorage['customjs'];
    			break;
    		default:
    			sendResponse({src: '', config: {}});
    	}
    	if( request.reload ) {
    		window.location.reload();
    	}
    });

})();