import { Issue } from "./githubType.ts";
import { readAll } from "https://deno.land/std@0.135.0/streams/mod.ts"
import { parse as argParse } from "https://deno.land/std@0.135.0/flags/mod.ts";
import { normalize, join as pathJoin, fromFileUrl } from "https://deno.land/std@0.135.0/path/mod.ts";
import * as Eta from "https://deno.land/x/eta/mod.ts";

async function readContent(path?: string): Promise<string> {
    let content = "[]";
    if (path) {
        content = await Deno.readTextFile(path);
    }
    else if (!Deno.isatty(Deno.stdin.rid)) {
        const decoder = new TextDecoder(undefined, { ignoreBOM: true });
        const buf = await readAll(Deno.stdin);
        content = decoder.decode(buf);
    }
    else throw new Error("No input provided. path or stdin.");
    return content;
}

async function readAndPrint(args: {
    path?: string,
    overall?: boolean,
    outpath?: string
}) {
    const c = await readContent(args.path);
    const issues = JSON.parse(c) as Issue[];
    issues.sort((a, b) => a.number - b.number);
    let print: string = "";
    if (args.overall) {
        print = await Eta.renderFile("overall.md", {
            issues: issues
        }) as string;
    }
    else {
        print = await Eta.renderFile("specific.md", {
            issues: issues
        }) as string;
    }
    if (args.outpath) {
        Deno.writeTextFileSync(args.outpath, print);
    }
    else {
        console.log(print);
    }
}

async function main() {
    const parsedArg = argParse(Deno.args);
    const { issue_path, outpath, overall, w, watch } = parsedArg;
    const watchMode = w || watch;
    if (typeof issue_path !== "undefined" && typeof issue_path !== "string") {
        console.log("Please provide a path to the json file.");
        Deno.exit(1);
    }
    if (typeof outpath !== "undefined" && typeof outpath !== "string") {
        console.log("Please provide a path to the output file.");
        Deno.exit(1);
    }
    if (typeof overall !== "undefined" && typeof overall !== "boolean") {
        console.log("Please provide a boolean value for overall.");
        Deno.exit(1);
    }
    if (typeof watchMode !== "undefined" && typeof watchMode !== "boolean") {
        console.log("Please provide a boolean value for w.");
        Deno.exit(1);
    }
    if (watchMode && typeof issue_path === "undefined") {
        console.log("Could not set watch mode without a path.");
        Deno.exit(1);
    }

    const url = new URL(import.meta.url)
    url.pathname = normalize(pathJoin(url.pathname, "..", "template"));
    const viewPath = fromFileUrl(url);
    Eta.configure({
        views: viewPath,
        "view cache": false,
    });

    const c = await readContent(issue_path);
    const issues = JSON.parse(c) as Issue[];
    issues.sort((a, b) => a.number - b.number);
    await readAndPrint({ path, outpath, overall });
    if (watchMode) {
        const watcher = Deno.watchFs([viewPath, path as string]);
        for await (const event of watcher) {
            if (event.kind === "modify") {
                Deno.stdout.write(
                    new TextEncoder().encode("\x1b[2J\x1b[0f"),
                );
                console.log(`reloading ${event.paths.join(", ")}`);
                readAndPrint({
                    path: path as string,
                    overall: overall as boolean,
                    outpath: outpath as string
                });
            }
        }
    }
}

if (import.meta.main) {
    main();
}