#!/usr/bin/env bun
import { existsSync, mkdirSync, readdirSync, readFileSync, statSync, writeFileSync } from "node:fs";
import { dirname, join, relative, resolve } from "node:path";

const PKG_ROOT = resolve(__dirname, "..");
const ASSETS_OUT = resolve(PKG_ROOT, "assets/skills");
const SOURCE_ROOT_DEFAULT = resolve(PKG_ROOT, "../../../../suaveplan-skills/plugins");

interface SkillEntry {
    readonly id: string;
    readonly version: string;
    readonly dir: string;
    readonly files: ReadonlyArray<string>;
}

function walk(dir: string, out: string[] = []): string[] {
    let entries: string[];
    try {
        entries = readdirSync(dir);
    } catch {
        return out;
    }
    for (const name of entries) {
        if (name === "node_modules" || name === ".git") continue;
        const p = join(dir, name);
        const st = statSync(p);
        if (st.isDirectory()) {
            walk(p, out);
        } else {
            out.push(p);
        }
    }
    return out;
}

function ensureDir(path: string): void {
    if (!existsSync(path)) mkdirSync(path, { recursive: true });
}

function copyFile(from: string, to: string): void {
    ensureDir(dirname(to));
    const bytes = readFileSync(from);
    writeFileSync(to, bytes);
}

function discoverSkills(sourceRoot: string): SkillEntry[] {
    if (!existsSync(sourceRoot)) {
        console.warn(`[build-skills-bundle] no source at ${sourceRoot} — skipping`);
        return [];
    }
    const skills: SkillEntry[] = [];
    const plugins = readdirSync(sourceRoot);
    for (const pluginName of plugins) {
        const pluginPath = join(sourceRoot, pluginName);
        if (!statSync(pluginPath).isDirectory()) continue;
        const skillsDir = join(pluginPath, "skills");
        if (!existsSync(skillsDir)) continue;
        for (const skillName of readdirSync(skillsDir)) {
            const skillSource = join(skillsDir, skillName);
            if (!statSync(skillSource).isDirectory()) continue;
            const skillManifest = join(skillSource, "SKILL.md");
            if (!existsSync(skillManifest)) continue;
            const targetDir = join(ASSETS_OUT, skillName);
            ensureDir(targetDir);
            const allFiles = walk(skillSource);
            const fileList: string[] = [];
            for (const file of allFiles) {
                const rel = relative(skillSource, file);
                copyFile(file, join(targetDir, rel));
                fileList.push(rel.split("\\").join("/"));
            }
            skills.push({
                id: skillName,
                version: "0.1.0",
                dir: skillName,
                files: fileList.sort(),
            });
        }
    }
    return skills.sort((a, b) => a.id.localeCompare(b.id));
}

function discoverExistingSkills(): SkillEntry[] {
    if (!existsSync(ASSETS_OUT)) {
        return [];
    }
    const skills: SkillEntry[] = [];
    for (const skillName of readdirSync(ASSETS_OUT)) {
        const skillPath = join(ASSETS_OUT, skillName);
        if (!statSync(skillPath).isDirectory()) continue;
        const skillManifest = join(skillPath, "SKILL.md");
        if (!existsSync(skillManifest)) continue;
        const allFiles = walk(skillPath);
        const fileList: string[] = [];
        for (const file of allFiles) {
            const rel = relative(skillPath, file);
            fileList.push(rel.split("\\").join("/"));
        }
        skills.push({
            id: skillName,
            version: "0.1.0",
            dir: skillName,
            files: fileList.sort(),
        });
    }
    return skills.sort((a, b) => a.id.localeCompare(b.id));
}

function writeManifest(skills: ReadonlyArray<SkillEntry>): void {
    ensureDir(ASSETS_OUT);
    const manifest = { schemaVersion: 1, skills };
    writeFileSync(
        join(ASSETS_OUT, "manifest.json"),
        `${JSON.stringify(manifest, null, 2)}\n`
    );
}

function main(): void {
    const sourceRoot = process.env["SUAVEPLAN_SKILLS_ROOT"] ?? SOURCE_ROOT_DEFAULT;
    let skills = discoverSkills(sourceRoot);
    if (skills.length === 0) {
        skills = discoverExistingSkills();
        if (skills.length > 0) {
            console.log(`[build-skills-bundle] source missing; regenerated manifest for ${skills.length} existing skills`);
        }
    }
    writeManifest(skills);
    console.log(`[build-skills-bundle] bundled ${skills.length} skills into ${ASSETS_OUT}`);
}

main();