import * as _ from "lodash";
import * as yargs from "yargs";
import * as scanner from "../scanner";
import * as handlebars from "handlebars";
import * as fs from "fs";

export var command = "list";
export var describe = "Extracts a YAML field into an ordered list";

export function builder(yargs: yargs.Arguments) {
    return yargs
        .help("help")

        .alias("t", "template")
        .default("template", "{{_number}}. {{{title}}}: {{{summary}}}")

        .alias("s", "trim-whitespace")
        .boolean("trim-whitspace")

        .alias("o", "output")
        .default("output", "-")

        .demand(1);
}

export function handler(argv: any) {
    var files = argv._.splice(1);
    var data = scanner.scanFiles(argv, files);
    render(argv, data);
}

export function render(argv, files) {
    // Compile the handlebars template.
    handlebars.registerHelper("eq", function (a, b) {
        return a === b;
    });
    handlebars.registerHelper("gt", function (a, b) {
        return a > b;
    });
    handlebars.registerHelper("gte", function (a, b) {
        return a >= b;
    });
    handlebars.registerHelper("lt", function (a, b) {
        return a < b;
    });
    handlebars.registerHelper("lte", function (a, b) {
        return a <= b;
    });
    handlebars.registerHelper("ne", function (a, b) {
        return a !== b;
    });

    const template = handlebars.compile(argv.template);

    // Go through each of the files and create a row from each one.
    const trim = /\s+/g;
    let output: string[] = [];

    for (var key in files) {
        // Combine everything into a single parameters object including `_number`
        // to represent the one-based index from the beginning.
        const number = 1 + parseInt(key.toString());

        let params = { ...files[key], _number: number };

        // Render the results and write it out.
        let result = template(params);

        if (argv.trimWhitespace) {
            result = result.replace(trim, " ").trim();
        }

        output.push(result);
    }

    // Write out the results as requested.
    if (argv.output === "-") {
        console.log(output.join("\n"));
    } else {
        fs.writeFileSync(argv.output, Buffer.from(output.join("\n"), "utf-8"));
    }
}