#!/usr/bin/env bun
// §15 lint: cross-package contracts must live in contract packages
import { readdirSync, readFileSync } from "node:fs";
import { join, relative, resolve } from "node:path";

const ROOT = resolve(import.meta.dir, "../..");
const PACKAGES_DIR = join(ROOT, "packages");
const CONTRACT_BASENAMES = new Set([
    "types",
    "api-types",
    "api-manifest",
    "api-router",
    "api-graphql",
    "api-ws",
    "api-sse",
    "api-auth",
    "api-auth-provider",
    "api-secrets",
    "api-tenant-provider",
    "api-loader",
    "api-lifecycle",
]);
const SUPPRESSION = "@cross-package-contract";

interface Decl {
    readonly name: string;
    readonly file: string;
    readonly pkg: string;
}

function walk(dir: string, out: string[]): void {
    for (const e of readdirSync(dir, { withFileTypes: true })) {
        if (
            e.name === "node_modules" ||
            e.name === "dist" ||
            e.name.startsWith(".")
        )
            continue;
        const full = join(dir, e.name);
        if (e.isDirectory()) walk(full, out);
        else if (
            e.isFile() &&
            full.endsWith(".ts") &&
            !full.endsWith(".test.ts") &&
            !full.endsWith(".spec.ts") &&
            !full.endsWith(".stories.tsx")
        )
            out.push(full);
    }
}

function pkgOf(src: string): string | null {
    const rel = relative(PACKAGES_DIR, src);
    const parts = rel.split("/");
    const idx = parts.indexOf("src");
    return idx > 0 ? (parts[idx - 1] ?? null) : null;
}

const files: string[] = [];
walk(PACKAGES_DIR, files);

const decls: Decl[] = [];
for (const f of files) {
    const text = readFileSync(f, "utf-8");
    const lines = text.split("\n");
    const re = /^\s*export\s+(?:interface\s+(\w+)|type\s+(\w+)\s*[=<])/;
    for (let i = 0; i < lines.length; i++) {
        const prev = i > 0 ? (lines[i - 1] ?? "") : "";
        if (prev.includes(SUPPRESSION)) continue;
        const m = re.exec(lines[i] ?? "");
        if (!m) continue;
        const name = m[1] ?? m[2];
        const pkg = pkgOf(f);
        if (!name || !pkg) continue;
        decls.push({ name, file: f, pkg });
    }
}

const byName = new Map<string, Decl>();
for (const d of decls) byName.set(d.name, d);

const violations = new Map<string, string[]>();
const implRe = /\bimplements\s+([A-Z]\w*)/g;
for (const f of files) {
    const consumerPkg = pkgOf(f);
    if (!consumerPkg) continue;
    const text = readFileSync(f, "utf-8");
    implRe.lastIndex = 0;
    let m: RegExpExecArray | null;
    while ((m = implRe.exec(text)) !== null) {
        const name = m[1];
        if (!name) continue;
        const d = byName.get(name);
        if (!d || d.pkg === consumerPkg) continue;
        if (CONTRACT_BASENAMES.has(d.pkg)) continue;
        const key = `${d.pkg}#${name}`;
        const arr = violations.get(key) ?? [];
        arr.push(`${relative(ROOT, f)} (${consumerPkg})`);
        violations.set(key, arr);
    }
}

if (violations.size === 0) {
    console.log(
        `✓ check-cross-package-contracts: 0 violations across ${files.length} files`
    );
    process.exit(0);
}
console.error(
    `✗ check-cross-package-contracts: ${violations.size} violation(s)`
);
console.error(
    "Per openspec/AGENTS.md §15, these types should move to a contract package"
);
console.error(
    "OR add `// @cross-package-contract` above the declaration to document why.\n"
);
for (const [k, cs] of violations) {
    const [pkg, name] = k.split("#");
    console.error(`  ${name} (in ${pkg}):`);
    for (const c of cs) console.error(`    implemented by: ${c}`);
}
process.exit(1);