chrome.runtime.onMessage.addListener(
    function (request, sender, sendResponse) {
        // console.log(request);
        if (request.from == "DataExtracter:Extract") {
            let data = extractData(request.itemsSelector, request.fieldSelectors);
            if (sendResponse) sendResponse(data);
        } else if (request.from == "DataExtracter:GotoUrl") {
            window.location.replace(request.url);
        } else if (request.from == "DataExtracter:ReportIn") {
            if (sendResponse) sendResponse(request.from);
        } else if (request.from == "DataExtracter:QueryUrl") {
            if (sendResponse) sendResponse(window.location.href);
        }
    }
);

function extractData(itemsSelector, fieldSelectors) {
    return $(itemsSelector).toArray().map(
        item => fieldSelectors.map(
            cls => $(item).find(cls).toArray().map(find => find.textContent.trim()).join('\n')
        )
    );
}

function extract(...args) {
    let sig = `Invalid call args.

function extract(itemsSelector:string, fieldSelectors:string[])
function extract(itemsSelector:string, fieldSelectors:string[], url:string, from:number, to:number, interval:number)
function extract(itemsSelector:string, fieldSelectors:string, url:string, pages:number[])`;
    if (!testArgs(...args)) {
        console.log(sig);
        return;
    }
    if (args.length == 2) {
        saveFileAsk(extractData(args[0], args[1]));
        return;
    }
    let message = {
        from: "DataExtracter:Extract",
        args: args
    }
    chrome.runtime.sendMessage(message, r => {
        if (r) {
            console.log(r);
            alert(r);
        }
    });
}

function testArgs(...args) {

    if (args.length < 2) return false;

    if (args.length == 2)
        return (args[0] && args[1] && (typeof args[0] == "string") && (args[1] instanceof Array))

    let urls = [];
    if (args.length > 2) return (typeof args[2] == "string") && (
        (args[3] instanceof Array) ||
        (!isNaN(args[3]) && !isNaN(args[4]) && !isNaN(args[5]))
    )
}