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, parse as parsePath } from "https://deno.land/std@0.135.0/path/mod.ts";
import * as Eta from "https://deno.land/x/eta@v1.12.3/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;
}
type printDocParam = {
    target: string,
    data: {
        issues: Issue[]
    }
};

async function printDoc(param: printDocParam, option?: {
    outDir?: string
}) {
    option = option ?? {};
    const { target, data } = param;
    const { outDir } = option;

    let print: string = "";
    print = await Eta.renderFile(target, data) as string;
    if (outDir) {
        const outPath = pathJoin(outDir, target);
        await Deno.mkdir(pathJoin(outDir), { recursive: true });
        await Deno.writeTextFile(outPath, print);
    }
    else {
        console.log(print);
    }
}

async function readAndPrint(args: {
    issue_path?: string,
    outDir?: string,
    targets: string[],
}) {
    const c = await readContent(args.issue_path);
    const issues = JSON.parse(c) as Issue[];
    issues.sort((a, b) => a.number - b.number);
    for (const target of args.targets) {
        await printDoc({
            target: target,
            data: {
                issues
            }
        }
            , {
                outDir: args.outDir
            });
    }
}

async function main() {
    const parsedArg = argParse(Deno.args);
    const { issue_path, outDir, 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 outDir !== "undefined" && typeof outDir !== "string") {
        console.log("Please provide a path to the output file.");
        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);

    const targets = ["SUMMARY.md", "overall.md", "specific.md", "intro.md", "support.md"];

    await readAndPrint({ issue_path, outDir, targets });
    if (watchMode) {
        const watcher = Deno.watchFs([viewPath, issue_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(", ")}`);
                let reloadAll = false;
                for (const path of event.paths) {
                    const p = parsePath(path);
                    if (targets.includes(p.base)) {
                        readAndPrint({
                            issue_path: issue_path as string,
                            outDir: outDir as string,
                            targets: [p.base]
                        });
                    }
                    else{
                        reloadAll = true;
                    }
                }
                if (reloadAll) {
                    readAndPrint({
                        issue_path: issue_path as string,
                        outDir: outDir as string,
                        targets: targets
                    });
                }
            }
        }
    }
}

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