#!/usr/bin/env bun
/**
 * Scaffold a new @suaveplan/audio-fx-plugin-<slug> package by:
 * 1. Copying every template under ./template/, replacing {PLUGIN_NAME} markers.
 * 2. git-mv'ing the source folder from packages/audio/audio-plugins-fx/src/plugins/<src-dir>/ → packages/audio-fx/audio-fx-plugin-<slug>/src/.
 * 3. Rewriting relative imports inside the moved sources to point at @suaveplan/audio-fx-plugin-base/* barrels.
 * 4. Rewriting @suaveplan/audio-plugins-fx/<slug> doc references to @suaveplan/audio-fx-plugin-<slug>.
 *
 * Usage:
 *   bun scripts/split-audio-fx-plugin/scaffold.ts --name compressor
 *   bun scripts/split-audio-fx-plugin/scaffold.ts --name game-audio --source-dir game
 *
 * After scaffold:
 *   bunx turbo lint typecheck test --filter=@suaveplan/audio-fx-plugin-<slug>
 *   bunx biome check --write src/   # may need formatting fix
 */
import { spawnSync } from "node:child_process";
import {
    existsSync,
    mkdirSync,
    readdirSync,
    readFileSync,
    rmdirSync,
    statSync,
    writeFileSync,
} from "node:fs";
import { dirname, join } from "node:path";
import { fileURLToPath } from "node:url";

const SLUG_RE = /^[a-z][a-z0-9-]*$/;
const SCRIPT_DIR = dirname(fileURLToPath(import.meta.url));
const TEMPLATE_DIR = join(SCRIPT_DIR, "template");
const REPO_ROOT = join(SCRIPT_DIR, "..", "..");
const SOURCE_PARENT = join(
    REPO_ROOT,
    "packages",
    "audio",
    "audio-plugins-fx",
    "src",
    "plugins"
);
const DEST_PARENT = join(REPO_ROOT, "packages", "audio");

interface Args {
    name: string;
    sourceDir: string;
    description: string;
}

function parseArgs(): Args {
    const argv = process.argv.slice(2);
    let name = "";
    let sourceDir = "";
    let description = "";
    for (let i = 0; i < argv.length; i++) {
        const flag = argv[i];
        const next = argv[i + 1];
        if (!next) continue;
        if (flag === "--name") {
            name = next;
            i++;
        } else if (flag === "--source-dir") {
            sourceDir = next;
            i++;
        } else if (flag === "--description") {
            description = next;
            i++;
        }
    }
    if (!name || !SLUG_RE.test(name)) {
        throw new Error(
            `--name must match /^[a-z][a-z0-9-]*$/ (got: ${JSON.stringify(name)})`
        );
    }
    if (!sourceDir) sourceDir = name;
    if (!description) {
        description = `${name} plugin for the @suaveplan/audio-fx-plugin-* family.`;
    }
    return { name, sourceDir, description };
}

function gitMv(from: string, to: string): void {
    const result = spawnSync("git", ["mv", from, to], {
        cwd: REPO_ROOT,
        stdio: "inherit",
    });
    if (result.status !== 0) {
        throw new Error(
            `git mv ${from} ${to} failed with status ${result.status}`
        );
    }
}

function walkFiles(dir: string, out: string[] = []): string[] {
    for (const entry of readdirSync(dir)) {
        const full = join(dir, entry);
        const st = statSync(full);
        if (st.isDirectory()) walkFiles(full, out);
        else out.push(full);
    }
    return out;
}

function substitute(content: string, args: Args): string {
    return content
        .replaceAll("{PLUGIN_NAME}", args.name)
        .replaceAll("{PLUGIN_DESCRIPTION}", args.description);
}

function copyTemplates(destPkg: string, args: Args): void {
    for (const entry of readdirSync(TEMPLATE_DIR)) {
        const src = join(TEMPLATE_DIR, entry);
        const destName = entry.endsWith(".template")
            ? entry.slice(0, -".template".length)
            : entry;
        const dest = join(destPkg, destName);
        const content = readFileSync(src, "utf8");
        writeFileSync(dest, substitute(content, args));
    }
}

function moveSource(args: Args, destPkg: string): void {
    const srcDir = join(SOURCE_PARENT, args.sourceDir);
    if (!existsSync(srcDir)) {
        throw new Error(`source dir not found: ${srcDir}`);
    }
    const destSrc = join(destPkg, "src");
    for (const child of readdirSync(srcDir)) {
        gitMv(join(srcDir, child), join(destSrc, child));
    }
    try {
        rmdirSync(srcDir);
    } catch {
        // Non-fatal: if non-empty, leave for manual inspection.
    }
}

const RELATIVE_IMPORT_REWRITES: Array<[RegExp, string]> = [
    // `base/<anything>.js` → base barrel
    [
        /from "\.\.\/\.\.\/base\/[a-z0-9./-]+\.js"/g,
        'from "@suaveplan/audio-fx-plugin-base/base"',
    ],
    // `chain/<anything>.js` (including nested context/, event-bus/, etc.) → chain barrel
    [
        /from "\.\.\/\.\.\/chain\/[a-z0-9./-]+\.js"/g,
        'from "@suaveplan/audio-fx-plugin-base/chain"',
    ],
    // `registry/<anything>.js` → registry barrel
    [
        /from "\.\.\/\.\.\/registry\/[a-z0-9./-]+\.js"/g,
        'from "@suaveplan/audio-fx-plugin-base/registry"',
    ],
    // root-level error-codes
    [
        /from "\.\.\/\.\.\/error-codes\.js"/g,
        'from "@suaveplan/audio-fx-plugin-base/error-codes"',
    ],
];

const CROSS_PLUGIN_RE = /from "\.\.\/[a-z][a-z0-9-]*\//;

function rewriteImports(destPkg: string, args: Args): void {
    const srcDir = join(destPkg, "src");
    for (const file of walkFiles(srcDir)) {
        if (!file.endsWith(".ts") && !file.endsWith(".md")) continue;
        let content = readFileSync(file, "utf8");
        const before = content;
        for (const [pattern, replacement] of RELATIVE_IMPORT_REWRITES) {
            content = content.replace(pattern, replacement);
        }
        content = content.replaceAll(
            `@suaveplan/audio-plugins-fx/${args.name}`,
            `@suaveplan/audio-fx-plugin-${args.name}`
        );
        const lines = content.split("\n");
        for (const line of lines) {
            if (
                CROSS_PLUGIN_RE.test(line) &&
                !line.includes("audio-fx-plugin-base")
            ) {
                throw new Error(
                    `Cross-plugin import detected in ${file}: ${line.trim()} — abort. ` +
                        "Fix the moved source manually, then re-run."
                );
            }
        }
        if (content !== before) writeFileSync(file, content);
    }
}

function main(): void {
    const args = parseArgs();
    const destPkg = join(DEST_PARENT, `audio-fx-plugin-${args.name}`);
    if (existsSync(destPkg)) {
        throw new Error(`destination already exists: ${destPkg}`);
    }
    mkdirSync(join(destPkg, "src"), { recursive: true });
    copyTemplates(destPkg, args);
    moveSource(args, destPkg);
    rewriteImports(destPkg, args);
    console.log(
        `scaffolded @suaveplan/audio-fx-plugin-${args.name} at ${destPkg}\n` +
            `next: bunx turbo lint typecheck test --filter=@suaveplan/audio-fx-plugin-${args.name}`
    );
}

main();