import init, { setup_panic_hook, Numbat, FormatType } from "./pkg/numbat_wasm.js";

async function fetch_exchange_rates() {
    try {
        const response = await fetch("https://numbat.dev/ecb-exchange-rates.php");

        if (!response.ok) {
            return;
        }

        const xml_content = await response.text();
        numbat.set_exchange_rates(xml_content);
    } catch (error) {
        console.error("Failed to load currency exchange rates from the European Central Bank");
        return;
    }
}

function create_numbat_instance() {
    return Numbat.new(true, true, FormatType.JqueryTerminal);
}

function updateUrlQuery(query) {
    let url = new URL(window.location);
    if (query == null) {
        url.searchParams.delete('q');
    } else {
        url.searchParams.set('q', query);
    }

    history.replaceState(null, null, url);
}

function interpret(input) {
    // Skip empty lines or comments
    var input_trimmed = input.trim();
    if (input_trimmed === "" || (input_trimmed[0] === "#" && input_trimmed.indexOf("\n") == -1)) {
        return;
    }

    if (input_trimmed == "clear") {
        this.clear();
        var output = "";
    } else if (input_trimmed == "reset") {
        numbat = create_numbat_instance();
        numbat.interpret("use units::currencies");
        combined_input = "";
        updateUrlQuery(null);
        this.clear();
    } else if (input_trimmed == "list") {
        output = numbat.print_environment();
    } else if (input_trimmed == "list functions") {
        output = numbat.print_functions();
    } else if (input_trimmed == "list dimensions") {
        output = numbat.print_dimensions();
    } else if (input_trimmed == "list variables") {
        output = numbat.print_variables();
    } else if (input_trimmed == "list units") {
        output = numbat.print_units();
    } else if (input_trimmed == "help" || input_trimmed == "?") {
        output = numbat.help();
    } else {
        var result = { is_error: false };
        if (input_trimmed.startsWith("info ")) {
            var keyword = input_trimmed.substring(4).trim();
            output = numbat.print_info(keyword);
        } else {
            result = numbat.interpret(input);
            output = result.output;
        }

        if (!result.is_error) {
            combined_input += input.trim() + "⏎";
            updateUrlQuery(combined_input);
        }
    }

    return output;
}

const parsedTerminalHeightInPixels = parseInt(
    getComputedStyle(document.documentElement).getPropertyValue(
        "--terminal-height"
    ),
    10
);

function setup() {
    $(document).ready(function () {
        var term = $('#terminal').terminal(interpret, {
            greetings: false,
            name: "terminal",
            height: parsedTerminalHeightInPixels,
            prompt: "[[;;;prompt]>>> ]",
            checkArity: false,
            historySize: 200,
            historyFilter(line) {
                return line.trim() !== "";
            },
            completion(inp, cb) {
                cb(numbat.get_completions_for(inp));
            }
        });

        // Swap out the skeleton loader with the terminal to prevent layout shifting.
        document.getElementById("skeleton-loader").classList.add("hidden");
        document.getElementById("terminal").classList.remove("hidden");

        // evaluate expression in query string if supplied (via opensearch)
        if (location.search) {
            var queryParams = new URLSearchParams(location.search);
            if (queryParams.has("q")) {
                // feed in the query line by line, as if the user typed it in
                for (const line of queryParams.get("q").split("⏎")) {
                    if (line.trim().length > 0) {
                        term.exec(line.trim() + "\n");
                    }
                }
            }
        }
    });
}

var numbat;
var combined_input = "";

async function main() {
    await init();

    setup_panic_hook();

    numbat = create_numbat_instance();
    combined_input = "";

    // Load KeyboardEvent polyfill for old browsers
    keyboardeventKeyPolyfill.polyfill();

    fetch_exchange_rates().then(setup);
}

main();