// Utility functions for tag autocomplete

// Parse the CSV file into a 2D array. Doesn't use regex, so it is very lightweight.
function parseCSV(str) {
    var arr = [];
    var quote = false;  // 'true' means we're inside a quoted field

    // Iterate over each character, keep track of current row and column (of the returned array)
    for (var row = 0, col = 0, c = 0; c < str.length; c++) {
        var cc = str[c], nc = str[c + 1];        // Current character, next character
        arr[row] = arr[row] || [];             // Create a new row if necessary
        arr[row][col] = arr[row][col] || '';   // Create a new column (start with empty string) if necessary

        // If the current character is a quotation mark, and we're inside a
        // quoted field, and the next character is also a quotation mark,
        // add a quotation mark to the current column and skip the next character
        if (cc == '"' && quote && nc == '"') { arr[row][col] += cc; ++c; continue; }

        // If it's just one quotation mark, begin/end quoted field
        if (cc == '"') { quote = !quote; continue; }

        // If it's a comma and we're not in a quoted field, move on to the next column
        if (cc == ',' && !quote) { ++col; continue; }

        // If it's a newline (CRLF) and we're not in a quoted field, skip the next character
        // and move on to the next row and move to column 0 of that new row
        if (cc == '\r' && nc == '\n' && !quote) { ++row; col = 0; ++c; continue; }

        // If it's a newline (LF or CR) and we're not in a quoted field,
        // move on to the next row and move to column 0 of that new row
        if (cc == '\n' && !quote) { ++row; col = 0; continue; }
        if (cc == '\r' && !quote) { ++row; col = 0; continue; }

        // Otherwise, append the current character to the current column
        arr[row][col] += cc;
    }
    return arr;
}

// Load file
async function readFile(filePath, json = false, cache = false) {
    if (!cache)
        filePath += `?${new Date().getTime()}`;
        
    let response = await fetch(`file=${filePath}`);

    if (response.status != 200) {
        console.error(`Error loading file "${filePath}": ` + response.status, response.statusText);
        return null;
    }

    if (json)
        return await response.json();
    else
        return await response.text();
}

// Load CSV
async function loadCSV(path) {
    let text = await readFile(path);
    return parseCSV(text);
}

// Debounce function to prevent spamming the autocomplete function
var dbTimeOut;
const debounce = (func, wait = 300) => {
    return function (...args) {
        if (dbTimeOut) {
            clearTimeout(dbTimeOut);
        }

        dbTimeOut = setTimeout(() => {
            func.apply(this, args);
        }, wait);
    }
}

// Difference function to fix duplicates not being seen as changes in normal filter
function difference(a, b) {
    if (a.length == 0) {
        return b;
    }
    if (b.length == 0) {
        return a;
    }

    return [...b.reduce((acc, v) => acc.set(v, (acc.get(v) || 0) - 1),
        a.reduce((acc, v) => acc.set(v, (acc.get(v) || 0) + 1), new Map())
    )].reduce((acc, [v, count]) => acc.concat(Array(Math.abs(count)).fill(v)), []);
}

function escapeRegExp(string) {
    return string.replace(/[.*+?^${}()|[\]\\]/g, '\\$&'); // $& means the whole matched string
}
function escapeHTML(unsafeText) {
    let div = document.createElement('div');
    div.textContent = unsafeText;
    return div.innerHTML;
}

// Queue calling function to process global queues
async function processQueue(queue, context, ...args) {
    for (let i = 0; i < queue.length; i++) {
        await queue[i].call(context, ...args);
    }
}
// The same but with return values
async function processQueueReturn(queue, context, ...args)
{
    let qeueueReturns = [];
    for (let i = 0; i < queue.length; i++) {
        let returnValue = await queue[i].call(context, ...args);
        if (returnValue)
            qeueueReturns.push(returnValue);
    }
    return qeueueReturns;
}
// Specific to tag completion parsers
async function processParsers(textArea, prompt) {
    // Get all parsers that have a successful trigger condition
    let matchingParsers = PARSERS.filter(parser => parser.triggerCondition());
    // Guard condition
    if (matchingParsers.length === 0) {
        return null;
    }

    let parseFunctions = matchingParsers.map(parser => parser.parse);
    // Process them and return the results
    return await processQueueReturn(parseFunctions, null, textArea, prompt);
}