class IndexFetcher {
    constructor() {
            this.combinedIndex = new Map();
            /**
             * key is shardid, value is true if the shard has been fetched and incorporated into the index var
             */
            this.shardsFetched = new Map();
        }
        /**
         * Fetch shard and incorporate it into the index.
         */
    async fetchShard(shardid) {
            if (this.shardsFetched.has(shardid)) {
                console.debug("not needing to fetch shard " + shardid);
                return;
            }
            console.debug("started fetching inx shard " + shardid);
            this.shardsFetched.set(shardid, false);
            let shard = await loadIndexFromURL(meta.inxURLBase + shardid.toString());
            for (let i of shard.keys()) {
                if (!inxFetcher.combinedIndex.has(i)) {
                    inxFetcher.combinedIndex.set(i, shard.get(i));
                } else {
                    //console.debug("this is weird, we fetched a token twice.")
                    //This is not weird if you're on firefox, bc there, the first key of a set is always an empty string.
                    if (i != "") {
                        console.warn("srsly weird");
                    }
                }
            }
            console.debug("shard " + shardid + " fetched!");
            inxFetcher.shardsFetched.set(shardid, true);
        }
        /**
         * Gets shardid that contains a given token/docid. Needs to have partMap fetched.
         * @param token
         * @return shardid
         */
    getIndexFor(token) {
        let needle = 0;
        while (meta.inxsplits[needle] < token) {
            needle++;
        }
        if (needle !== 0) {
            return needle - 1;
        } else
            return needle;
    }
}
class InvertedIndexFetcher extends IndexFetcher {
    constructor() {
            super(...arguments);
            this.combinedInvIndex = new Map();
        }
        /**
         * Fetch shard and incorporate it into the index.
         */
    async fetchShard(shardid) {
            if (this.shardsFetched.has(shardid)) {
                return;
            }
            console.debug("started fetching invinx shard " + shardid);
            this.shardsFetched.set(shardid, false);
            let shard = await loadInvertedIndexFromURL(meta.invURLBase + shardid.toString());
            for (let i of shard.keys()) {
                if (!invinxFetcher.combinedInvIndex.has(i)) {
                    invinxFetcher.combinedInvIndex.set(i, shard.get(i));
                } else {
                    //console.debug("this is weird, we fetched a token twice.")
                    //This is not weird if you're on firefox, bc there, the first key of a set is always an empty string.
                    if (i != "") {
                        console.warn("srsly weird");
                    }
                }
            }
            console.debug("invinx shard " + shardid + " fetched!");
            invinxFetcher.shardsFetched.set(shardid, true);
        }
        /**
         * Gets shardid that contains a given token/docid. Needs to have partMap fetched.
         * @param token
         * @return shardid
         */
    getIndexFor(token) {
        let needle = 0;
        while (meta.invsplits[needle] < token) {
            needle++;
        }
        if (needle !== 0) {
            return needle - 1;
        } else
            return needle;
    }
}
var inxFetcher = new IndexFetcher();
var invinxFetcher = new InvertedIndexFetcher();
var meta;
var app;
let ipfsGatewayURL;
const NUMRESULTS = 30;

function onLoad() {
    let params = new URLSearchParams(location.search);
    if (params.get("index")) {
        loadMeta(params.get("index")).then(function() { document.getElementById("app").style.visibility = ""; });
    } else {
        document.getElementById("app").style.visibility = "";
    }
}
async function loadMeta(metaURL) {
    let response;
    if (metaURL.startsWith("/ipfs/") || metaURL.startsWith("/ipns/")) {
        response = await fetch((await getIpfsGatewayUrlPrefix()) + metaURL);
    } else {
        response = await fetch(metaURL);
    }
    const json = await response.text();
    try {
        meta = JSON.parse(json);
    } catch (e) {
        app.error = "Unable to find index at " + metaURL;
        return;
    }
    if (meta.invURLBase.startsWith("/ipfs/") || meta.invURLBase.startsWith("/ipns/")) {
        meta.invURLBase = (await getIpfsGatewayUrlPrefix()) + meta.invURLBase;
    }
    if (meta.inxURLBase.startsWith("/ipfs/") || meta.inxURLBase.startsWith("/ipns/")) {
        meta.inxURLBase = (await getIpfsGatewayUrlPrefix()) + meta.inxURLBase;
    }
    console.log("meta fetched");
    app.showmeta = false;
    app.showsearchbox = true;
    app.indexAuthor = meta.author;
    app.indexName = meta.name;
    app.entries = meta.entries;
    let ts = new Date(meta.created);
    app.indexTimestamp = ts.getDate().toString() + "/" + (ts.getMonth() + 1).toString() + "/" + ts.getFullYear().toString();
    if (meta.resultPage == undefined) {
        app.resultPage = "basicresultpage";
    } else {
        if (meta.resultPage.startsWith("/ipfs/") || meta.resultPage.startsWith("/ipns/")) {
            app.resultPage = (await getIpfsGatewayUrlPrefix()) + meta.resultPage;
        } else {
            app.resultPage = meta.resultPage;
        }
    }
}
/**
 * Returns the IPFS gateway. If there is no set, tries to use localhost, otherwise prompts the user to install one on localhost.
 *
 * If it fails to get one, it aborts the whole page by using document.write and prompting the user to install an IPFS daemon on localhost.
 *
 * Return format is http://ipfsgateway.tld(:port)
 * note the absence of a trailing slash.
 */
async function getIpfsGatewayUrlPrefix() {
    if (ipfsGatewayURL !== undefined) {
        return ipfsGatewayURL;
    }
    if (window.location.protocol === "https:") {
        if (await checkIfIpfsGateway("")) {
            ipfsGatewayURL = window.location.protocol + "//" + window.location.host;
        } else {
            app.error = "ipfsearch is currently being served from a HTTPS host that is not an IPFS node. This prevents it from using a local IPFS gateway. The node operator should fix this and run an ipfs gateway.";
        }
    } else if (await checkIfIpfsGateway("http://localhost:8080")) {
        ipfsGatewayURL = "http://localhost:8080";
    } else if (await checkIfIpfsGateway("http://" + window.location.host)) {
        ipfsGatewayURL = "http://" + window.location.host;
    } else {
        app.error = "Loading of the index requires access to the IPFS network. We have found no running IPFS daemon on localhost. Please install IPFS from <a href='http://ipfs.io/docs/install'>ipfs.io</a> and refresh this page.";
        throw new Error("Couldn't get a IPFS gateway.");
    }
    return ipfsGatewayURL;
}
/**
 * Checks if a given endpoint is a valid IPFS gateway by fetching a "hello world" file over IPFS.
 * @param gatewayURL in format http://ipfsgateway.tld(:port)
 */
async function checkIfIpfsGateway(gatewayURL) {
    let response = await fetch(gatewayURL + "/ipfs/QmT78zSuBmuS4z925WZfrqQ1qHaJ56DQaTfyMUF7F8ff5o");
    if ((await response.text()).startsWith("hello world")) { //had to use startsWith bc \n on the end of the file
        return true;
    } else {
        return false;
    }
}

function setQueryParam(s) {
    let params = URLSearchParams(window.location.search)
    params.set("q", s);
    var newRelativePathQuery = window.location.pathname + '?' + params.toString();
    history.pushState(null, '', newRelativePathQuery);
}

function searchTriggered() {
    let searchbox = document.getElementById("searchbox");
    let querytokens = searchbox.value.split(" ");
    passQueryToResultpage(searchbox.value)
    querytokens = querytokens.map(querytoken => {
        return stemmer(querytoken);
    });
    console.debug("searching for: " + querytokens.join(" "));
    searchFor(querytokens.join(" "));
}

function searchFor(query) {
    passProgressToResultpage(0);
    let runningFetches = [];
    let tokenizedquery = tokenize(query);
    tokenizedquery.forEach((token) => {
        runningFetches.push(invinxFetcher.fetchShard(invinxFetcher.getIndexFor(token)));
    });
    let invToFetch = runningFetches.length;
    let invFetched = 0;
    runningFetches.forEach((fetch) => {
        fetch.then(() => {
            invFetched++;
            passProgressToResultpage(0.5 * invFetched / invToFetch);
        });
    });
    Promise.all(runningFetches).then(() => {
        let candidates = getAllCandidates(tokenizedquery, invinxFetcher.combinedInvIndex);
        console.log("candidates prefilter: " + candidates.size);
        console.debug(candidates);
        candidates = filterCandidates(candidates, tokenizedquery.length);
        console.log("candidates postfilter: " + candidates.size);
        passProgressToResultpage(0.6);
        let resultIds;
        resultIds = [];
        /**
         * Have we already found the most relevant candidate (=matches all tokens in query)?
         */
        let foundIdealCandidate;
        for (let key of candidates.keys()) {
            if (candidates.get(key) == tokenizedquery.length) {
                foundIdealCandidate = true;
            }
            resultIds.push(key);
        }
        console.debug(candidates);
        if (foundIdealCandidate) {
            console.info("Found an ideal candidate in prefetch sorting&filtering. Filtering out all non-ideal candidates...");
            resultIds = resultIds.filter((resultId) => {
                if (candidates.get(resultId) != tokenizedquery.length) {
                    return false;
                } else {
                    return true;
                }
            });
        } else { //sort them by relevance
            resultIds = resultIds.sort((a, b) => {
                let ascore = candidates.get(a);
                let bscore = candidates.get(b);
                if (ascore > bscore) {
                    return -1;
                } else if (ascore > bscore) {
                    return 1;
                } else {
                    return 0;
                }
            });
        }
        console.debug("resultIds after prefetch sorting & filtering: ");
        console.debug(resultIds);
        let resultIdsToFetch = resultIds.slice(0, NUMRESULTS);
        passProgressToResultpage(0.7);
        fetchAllDocumentsById(resultIdsToFetch).then((results) => {
            passProgressToResultpage(0.95);
            passResultToResultpage(results);
            //fetch all results, not just the first NUMRESULTS
            resultIds = resultIds.slice(0, 1000);
            fetchAllDocumentsById(resultIds).then((results) => {
                passProgressToResultpage(1);
                passResultToResultpage(results);
            });
        });
    });
}

function passResultToResultpage(results) {
    let resultPageIframe = document.getElementById("resultPage");
    resultPageIframe.contentWindow.postMessage({
        type: "results",
        results: JSON.stringify(results)
    }, '*');
}
/**
 *
 * @param progress Number between 0 and 1 representing fractional progress made in search.
 */
function passProgressToResultpage(progress) {
    if (progress > 1) {
        throw Error("progress passed to resultpage must be < 1");
    }
    console.log("Progress: " + (progress * 100).toString());
    let resultPageIframe = document.getElementById("resultPage");
    resultPageIframe.contentWindow.postMessage({
        type: "progress",
        progress: progress
    }, '*');
}
/**
 * @param ids array of document ids to fetch
 * @returns An array of fetched documents in the same order as ids.
 */
async function fetchAllDocumentsById(ids) {
    let runningDocumentFetches;
    runningDocumentFetches = [];
    for (let id in ids) {
        runningDocumentFetches.push(getDocumentForId(ids[id])); ///ooooh order gets messed up? maybeee?
    }
    return Promise.all(runningDocumentFetches).then((results) => {
        return results;
    });
}
/**
 * Filter out candidates that are not relevant enough to fetch.
 *
 * Example: Say the user has searched for 5 terms. This filters all candidates that match less than 3 of them, if there are some that match all 5.
 *
 * We are doing this now, before fetching the index (not invinx), to minimize the size of the part of the index that we have to download.
 *
 * For higher recall, this should not be used.
 */
function filterCandidates(candidates, tokensInQuery) {
    if (tokensInQuery >= 2) {
        let filteredCandidates;
        filteredCandidates = new Map();
        for (let key of candidates.keys()) {
            if (candidates.get(key) >= (tokensInQuery / 2)) {
                filteredCandidates.set(key, candidates.get(key));
            }
        }
        candidates = undefined;
        return filteredCandidates;
    } else {
        return candidates;
    }
}
/**
 * Return all candidates that match at least one token from the query.
 * Searches only in the part of index that is already downloaded, to it assumes that all required shards are already fetched.
 * @returns a Map, mapping an infohash to the number of times the candidate appeared in the index for given query.
 */
function getAllCandidates(query, index) {
    /**
     * Maps the infohash of a candidate to the number of times it appeared in results
     */
    let candidates;
    candidates = new Map();
    for (let i in query) {
        let result = index.get(query[i]);
        for (let j in result) {
            if (candidates.has(result[j])) {
                candidates.set(result[j], candidates.get(result[j]) + 1); //if candidate already in set, increment the counter of how many times it appeared in the index for the query
            } else {
                candidates.set(result[j], 1);
            }
        }
    }
    return candidates;
}
// Porter stemmer in Javascript. Few comments, but it's easy to follow against the rules in the original
// paper, in
//
//  Porter, 1980, An algorithm for suffix stripping, Program, Vol. 14,
//  no. 3, pp 130-137,
//
// see also http://www.tartarus.org/~martin/PorterStemmer
// Release 1 be 'andargor', Jul 2004
// Release 2 (substantially revised) by Christopher McKenzie, Aug 2009
var stemmer = (function() {
    var step2list = {
            "ational": "ate",
            "tional": "tion",
            "enci": "ence",
            "anci": "ance",
            "izer": "ize",
            "bli": "ble",
            "alli": "al",
            "entli": "ent",
            "eli": "e",
            "ousli": "ous",
            "ization": "ize",
            "ation": "ate",
            "ator": "ate",
            "alism": "al",
            "iveness": "ive",
            "fulness": "ful",
            "ousness": "ous",
            "aliti": "al",
            "iviti": "ive",
            "biliti": "ble",
            "logi": "log"
        },
        step3list = {
            "icate": "ic",
            "ative": "",
            "alize": "al",
            "iciti": "ic",
            "ical": "ic",
            "ful": "",
            "ness": ""
        },
        c = "[^aeiou]", // consonant
        v = "[aeiouy]", // vowel
        C = c + "[^aeiouy]*", // consonant sequence
        V = v + "[aeiou]*", // vowel sequence
        mgr0 = "^(" + C + ")?" + V + C, // [C]VC... is m>0
        meq1 = "^(" + C + ")?" + V + C + "(" + V + ")?$", // [C]VC[V] is m=1
        mgr1 = "^(" + C + ")?" + V + C + V + C, // [C]VCVC... is m>1
        s_v = "^(" + C + ")?" + v; // vowel in stem
    return function(w) {
        var stem, suffix, firstch, re, re2, re3, re4, origword = w;
        if (w.length < 3) {
            return w;
        }
        firstch = w.substr(0, 1);
        if (firstch == "y") {
            w = firstch.toUpperCase() + w.substr(1);
        }
        // Step 1a
        re = /^(.+?)(ss|i)es$/;
        re2 = /^(.+?)([^s])s$/;
        if (re.test(w)) {
            w = w.replace(re, "$1$2");
        } else if (re2.test(w)) {
            w = w.replace(re2, "$1$2");
        }
        // Step 1b
        re = /^(.+?)eed$/;
        re2 = /^(.+?)(ed|ing)$/;
        if (re.test(w)) {
            var fp = re.exec(w);
            re = new RegExp(mgr0);
            if (re.test(fp[1])) {
                re = /.$/;
                w = w.replace(re, "");
            }
        } else if (re2.test(w)) {
            var fp = re2.exec(w);
            stem = fp[1];
            re2 = new RegExp(s_v);
            if (re2.test(stem)) {
                w = stem;
                re2 = /(at|bl|iz)$/;
                re3 = new RegExp("([^aeiouylsz])\\1$");
                re4 = new RegExp("^" + C + v + "[^aeiouwxy]$");
                if (re2.test(w)) {
                    w = w + "e";
                } else if (re3.test(w)) {
                    re = /.$/;
                    w = w.replace(re, "");
                } else if (re4.test(w)) {
                    w = w + "e";
                }
            }
        }
        // Step 1c
        re = /^(.+?)y$/;
        if (re.test(w)) {
            var fp = re.exec(w);
            stem = fp[1];
            re = new RegExp(s_v);
            if (re.test(stem)) {
                w = stem + "i";
            }
        }
        // Step 2
        re = /^(.+?)(ational|tional|enci|anci|izer|bli|alli|entli|eli|ousli|ization|ation|ator|alism|iveness|fulness|ousness|aliti|iviti|biliti|logi)$/;
        if (re.test(w)) {
            var fp = re.exec(w);
            stem = fp[1];
            suffix = fp[2];
            re = new RegExp(mgr0);
            if (re.test(stem)) {
                w = stem + step2list[suffix];
            }
        }
        // Step 3
        re = /^(.+?)(icate|ative|alize|iciti|ical|ful|ness)$/;
        if (re.test(w)) {
            var fp = re.exec(w);
            stem = fp[1];
            suffix = fp[2];
            re = new RegExp(mgr0);
            if (re.test(stem)) {
                w = stem + step3list[suffix];
            }
        }
        // Step 4
        re = /^(.+?)(al|ance|ence|er|ic|able|ible|ant|ement|ment|ent|ou|ism|ate|iti|ous|ive|ize)$/;
        re2 = /^(.+?)(s|t)(ion)$/;
        if (re.test(w)) {
            var fp = re.exec(w);
            stem = fp[1];
            re = new RegExp(mgr1);
            if (re.test(stem)) {
                w = stem;
            }
        } else if (re2.test(w)) {
            var fp = re2.exec(w);
            stem = fp[1] + fp[2];
            re2 = new RegExp(mgr1);
            if (re2.test(stem)) {
                w = stem;
            }
        }
        // Step 5
        re = /^(.+?)e$/;
        if (re.test(w)) {
            var fp = re.exec(w);
            stem = fp[1];
            re = new RegExp(mgr1);
            re2 = new RegExp(meq1);
            re3 = new RegExp("^" + C + v + "[^aeiouwxy]$");
            if (re.test(stem) || (re2.test(stem) && !(re3.test(stem)))) {
                w = stem;
            }
        }
        re = /ll$/;
        re2 = new RegExp(mgr1);
        if (re.test(w) && re2.test(w)) {
            re = /.$/;
            w = w.replace(re, "");
        }
        // and turn initial Y back to y
        if (firstch == "y") {
            w = firstch.toLowerCase() + w.substr(1);
        }
        return w;
    };
})();
/**
 * Tokenizes string into an array of tokens and filters out stopwords.
 * @param name string to get tokenized
 */
function tokenize(name) {
    let tokens = name.split(' ').join(',').split('.').join(',').split('(').join(',').split(')').join(',').split('-').join(',').split('_').join(',').split(','); // super super awful and nasty, but gets the job done.
    tokens.forEach((value, index, array) => { array[index] = value.toLowerCase(); });
    tokens.forEach((value, index, array) => { array[index] = stemmer(value); });
    return tokens;
}
/**
 * @param url location of the index of documents
 */
async function loadIndexFromURL(url) {
    let response = await fetch(url);
    let responsetext;
    if (response.ok) {
        responsetext = await response.text();
    } else {
        throw new Error(response.statusText);
    }
    let parsedResponse = JSON.parse(responsetext);
    let parsedIndex;
    parsedIndex = new Map();
    for (let object of parsedResponse) {
        let id = "";
        let document = new Object();
        for (let property of Object.keys(object)) {
            if (property === "id") {
                id = object[property];
            } else {
                document[property] = object[property];
            }
        }
        parsedIndex.set(id, document);
    }
    return parsedIndex;
}
/**
 * @returns a Promise that returns an index
 */
function loadInvertedIndexFromURL(url) {
    return fetch(url).then((response) => {
        if (response.ok) {
            return response.text();
        }
        throw new Error("Couldn't fetch shard at URL " + url);
    }).then((response) => {
        let loadedIndex = new Map();
        let lineNumber = 0;
        let lines = response.split("\n");
        let version;
        lines.forEach((line) => {
            if (lineNumber === 0) {
                if (parseInt(line) != 1 && parseInt(line) != 2) {
                    throw "Error while parsing invinx: Invalid version, must be 1 or 2!";
                } else {
                    version = parseInt(line);
                }
                lineNumber++;
                return;
            }
            let cols = line.split(",");
            let tokenname = decodeURIComponent(cols[0]);
            cols.shift();
            if (version === 2) {
                cols = cols.map(function(value) {
                    return value.replace("%2C", ",");
                });
            }
            loadedIndex.set(tokenname, cols);
            lineNumber++;
        });
        return (loadedIndex);
    });
}
async function getDocumentForId(docid) {
    docid = docid.replace("%2C", ",");
    await inxFetcher.fetchShard(inxFetcher.getIndexFor(docid));
    if (inxFetcher.combinedIndex.get(docid) === undefined) {
        console.error("No document found for docid " + docid);
        return { text: "no document found", id: docid };
    }
    let doc = inxFetcher.combinedIndex.get(docid);
    doc["id"] = docid;
    return inxFetcher.combinedIndex.get(docid);
}


function passResultToResultpage(results) {
    let resultPageIframe = document.getElementById("resultPage");
    resultPageIframe.contentWindow.postMessage({
        type: "results",
        results: JSON.stringify(results)
    }, '*');
}

function passQueryToResultpage(query) {
    let resultPageIframe = document.getElementById("resultPage");
    resultPageIframe.contentWindow.postMessage({
        type: "query",
        query: query
    }, '*');
}