import { join } from "https://deno.land/std@0.208.0/path/mod.ts";
import { emptyDir } from "https://deno.land/std@0.196.0/fs/empty_dir.ts";
import { setWeek, nextMonday, format, addDays } from 'npm:date-fns';
import { marked } from 'npm:marked';
import matter from 'npm:front-matter';

const SRC_DIR = "./data";
const DEST_DIR = "./dist";

async function build() {
    let issues = [];
    for await (const dirEntry of Deno.readDir(SRC_DIR)) {
        if (!dirEntry.isDirectory || !dirEntry.name.match(/^\d{4}$/)) {
            continue;
        }
        //const [fn, ext] = dirEntry.name.split(".");
        const year = dirEntry.name;
        const yearDir = join(SRC_DIR, year);
        console.log(`Processing year: ${year}`);
        for await (const dirEntry of Deno.readDir(yearDir)) {
            const [fn, ext] = dirEntry.name.split(".");
            const weekMatch = fn.match(/^week(\d{2})$/)
            if (!weekMatch || ext !== "md") {
                continue;
            }
            const week = weekMatch[1]
            const mdPath = join(SRC_DIR, year, dirEntry.name);
            const source = await Deno.readTextFile(mdPath);

            const issue = {
                week: `${year}-${week}`,
                period: calcPeriod(year, week),
            }

            await renderData(issue, source)
            issues.push(issue)
        }
    }

    await emptyDir(DEST_DIR);
    const outputFn = join(DEST_DIR, "index.json");
    await writeJSONFile(outputFn, issues);
}

async function renderData(issue, source) {
    const fm = matter(source);

    const parsed = marked.parse(fm.body);
    return Object.assign(issue, fm.attributes, { newsMd: fm.body, newsHtml: parsed });

    //const fm = matter(issue.source)
    //console.log(fm)
    //console.log(parsed)
    //return
}

function calcPeriod(year, week) {
    const weekStart = setWeek(nextMonday(new Date(Number(year), 0, 4)), Number(week), {
        weekStartsOn: 1,
        firstWeekContainsDate: 4,
    });
    const weekEnd = addDays(weekStart, 6);

    return [ weekStart, weekEnd ];
} 

async function writeJSONFile(fn, data) {
    console.log(`File written: ${fn}`);
    return Deno.writeTextFile(fn, JSON.stringify(data, null, 2));
}

build();