#!/usr/bin/env bun
/**
 * check-no-backwards-deps.ts
 *
 * CI gate enforcing the React-stack dependency-direction invariant
 * declared in:
 *   - openspec/changes/enterprise-react-i18n/specs/react-i18n/spec.md
 *     ("Branded TranslationKey typing contract")
 *   - openspec/cross-cutting-designs/2026-05-05-react-ui-react-i18n-react-forms.md §11.2
 *
 * The React stack has a strict layered hierarchy:
 *
 *     react-i18n  (foundation; has no upstream React-stack deps)
 *         ▲
 *     react-ui    (depends on react-i18n only)
 *         ▲
 *     react-forms (depends on react-i18n + react-ui)
 *         ▲
 *     react-ui-theme-*  (depends on react-i18n + react-ui)
 *     react-ui-pack-*   (depends on react-i18n + react-ui [+ react-forms])
 *
 * Each tier MUST NOT declare a downstream-tier package in its
 * `dependencies`, `peerDependencies`, or `devDependencies` — otherwise
 * the layering inverts, the TranslationKey augmentation contract breaks,
 * and tree-shaking guarantees collapse.
 *
 * This script reads a package.json, identifies the package by its `name`,
 * computes the appropriate banned-pattern subset for that tier, and
 * checks the three dep buckets. Exits non-zero with a structured
 * diagnostic listing every offending (bucket, package) pair.
 *
 * Packages outside the React stack (`@suaveplan/error`, `@suaveplan/i18n`,
 * `@some/other`) get a no-op pass — this gate is React-stack-specific.
 *
 * Usage:
 *   bun scripts/lint/check-no-backwards-deps.ts [--root <repo-root>]
 *                                              [--package-json <path>]
 *
 * Exit codes:
 *   0  — package.json declares no banned deps (or is outside React stack)
 *   1  — at least one banned dep found (details on stderr)
 *   2  — internal error (cannot read or parse package.json)
 */

import { readFile } from "node:fs/promises";
import { join, resolve } from "node:path";

export interface BannedPattern {
    readonly label: string;
    readonly match: (depName: string) => boolean;
}

const PATTERN_REACT_UI_THEME: BannedPattern = {
    label: "@suaveplan/react-ui-theme-*",
    match: (n) => n.startsWith("@suaveplan/react-ui-theme-"),
};

const PATTERN_REACT_UI_PACK: BannedPattern = {
    label: "@suaveplan/react-ui-pack-*",
    match: (n) => n.startsWith("@suaveplan/react-ui-pack-"),
};

const PATTERN_REACT_UI: BannedPattern = {
    label: "@suaveplan/react-ui*",
    match: (n) =>
        n === "@suaveplan/react-ui" ||
        (n.startsWith("@suaveplan/react-ui-") &&
            !n.startsWith("@suaveplan/react-ui-theme-") &&
            !n.startsWith("@suaveplan/react-ui-pack-")),
};

const PATTERN_REACT_FORMS: BannedPattern = {
    label: "@suaveplan/react-forms*",
    match: (n) =>
        n === "@suaveplan/react-forms" ||
        n.startsWith("@suaveplan/react-forms-"),
};

/**
 * Full registry of every banned-pattern in the React stack. Per-tier
 * banned subsets are derived from this set. Stable for downstream
 * consumers (test fixtures, doc generators).
 */
export const BANNED_PATTERNS: ReadonlyArray<BannedPattern> = [
    PATTERN_REACT_UI_THEME,
    PATTERN_REACT_UI_PACK,
    PATTERN_REACT_UI,
    PATTERN_REACT_FORMS,
];

/**
 * Per-tier banned-pattern map. Each tier's entry lists the patterns
 * that MUST NOT appear in any of its dep buckets. Computed from the
 * stack hierarchy:
 *
 *   react-i18n      → bans every leaf (react-ui*, react-forms*, theme-*, pack-*)
 *   react-ui        → bans every leaf below it (react-forms*, theme-*, pack-*)
 *   react-forms     → bans theme-* and pack-* only (CAN dep react-ui)
 *   react-ui-theme-* → bans react-forms* and pack-* (themes are siblings of forms;
 *                       packs sit downstream of themes)
 *   react-ui-pack-*  → bans nothing in the React stack (packs are bottom-most)
 */
const TIER_BANNED: Record<string, ReadonlyArray<BannedPattern>> = {
    "@suaveplan/react-i18n": BANNED_PATTERNS,
    "@suaveplan/react-ui": [
        PATTERN_REACT_UI_THEME,
        PATTERN_REACT_UI_PACK,
        PATTERN_REACT_FORMS,
    ],
    "@suaveplan/react-forms": [PATTERN_REACT_UI_THEME, PATTERN_REACT_UI_PACK],
};

/**
 * Compute the banned-pattern subset for a given package name. Returns
 * an empty array for packages outside the React stack so the gate
 * no-ops on them.
 */
export function bannedPatternsFor(
    packageName: string | undefined
): ReadonlyArray<BannedPattern> {
    if (typeof packageName !== "string") return [];
    if (Object.hasOwn(TIER_BANNED, packageName)) {
        return TIER_BANNED[packageName] as ReadonlyArray<BannedPattern>;
    }
    if (packageName.startsWith("@suaveplan/react-ui-theme-")) {
        return [PATTERN_REACT_FORMS, PATTERN_REACT_UI_PACK];
    }
    if (packageName.startsWith("@suaveplan/react-ui-pack-")) {
        return [];
    }
    return [];
}

/**
 * The package.json buckets we inspect. Listed explicitly (rather than
 * walking every key) so the rule is auditable and so unrelated buckets
 * (e.g. `optionalDependencies`, `bundleDependencies`) cannot smuggle a
 * banned dep through.
 */
export const INSPECTED_BUCKETS = [
    "dependencies",
    "peerDependencies",
    "devDependencies",
] as const;

export type InspectedBucket = (typeof INSPECTED_BUCKETS)[number];

export interface Violation {
    readonly bucket: InspectedBucket;
    readonly depName: string;
    readonly version: string;
    readonly matchedPattern: string;
}

export interface CheckOptions {
    readonly packageJsonPath: string;
    readonly readFileFn?: typeof readFile;
}

/**
 * Read the supplied `package.json` and return every banned dep
 * declared in `dependencies`, `peerDependencies`, or
 * `devDependencies`. Buckets that are absent or malformed contribute
 * zero violations (a malformed bucket is the consumer's bug — out of
 * scope for this gate).
 */
export async function findViolations(
    options: CheckOptions
): Promise<Violation[]> {
    const readImpl = options.readFileFn ?? readFile;
    let raw: string;
    try {
        raw = await readImpl(options.packageJsonPath, "utf8");
    } catch (cause) {
        throw new Error(
            `check-no-backwards-deps: cannot read ${options.packageJsonPath}: ${(cause as Error).message}`
        );
    }
    let manifest: Record<string, unknown>;
    try {
        manifest = JSON.parse(raw) as Record<string, unknown>;
    } catch (cause) {
        throw new Error(
            `check-no-backwards-deps: cannot parse ${options.packageJsonPath}: ${(cause as Error).message}`
        );
    }
    const packageName =
        typeof manifest.name === "string" ? manifest.name : undefined;
    const banned = bannedPatternsFor(packageName);
    if (banned.length === 0) return [];
    const violations: Violation[] = [];
    for (const bucket of INSPECTED_BUCKETS) {
        const value = manifest[bucket];
        if (value === undefined || value === null) continue;
        if (typeof value !== "object" || Array.isArray(value)) continue;
        const deps = value as Record<string, unknown>;
        for (const [depName, depVersion] of Object.entries(deps)) {
            for (const pattern of banned) {
                if (!pattern.match(depName)) continue;
                violations.push({
                    bucket,
                    depName,
                    version:
                        typeof depVersion === "string"
                            ? depVersion
                            : JSON.stringify(depVersion),
                    matchedPattern: pattern.label,
                });
            }
        }
    }
    return violations;
}

/**
 * Render a human-readable diagnostic block. The empty-violations form
 * is the single line printed on stdout for the success case.
 */
export function formatViolations(violations: readonly Violation[]): string {
    if (violations.length === 0) {
        return "Package declares no React-stack backward dependencies.";
    }
    const lines: string[] = [
        "❌ React-stack backward dependencies detected.",
        "",
        "Rule: openspec/cross-cutting-designs/2026-05-05-react-ui-react-i18n-react-forms.md §11.2.",
        "Fix:  remove the dep — each tier in the stack must only depend on tiers",
        "      strictly above it (react-i18n → react-ui → react-forms / theme / pack).",
        "",
    ];
    const grouped = new Map<InspectedBucket, Violation[]>();
    for (const v of violations) {
        const list = grouped.get(v.bucket) ?? [];
        list.push(v);
        grouped.set(v.bucket, list);
    }
    for (const bucket of INSPECTED_BUCKETS) {
        const items = grouped.get(bucket);
        if (!items || items.length === 0) continue;
        lines.push(
            `  ${bucket} (${items.length} violation${items.length === 1 ? "" : "s"})`
        );
        for (const v of items) {
            lines.push(
                `    ${v.depName}@${v.version}  (matched: ${v.matchedPattern})`
            );
        }
        lines.push("");
    }
    lines.push(
        `Total: ${violations.length} violation${violations.length === 1 ? "" : "s"}.`
    );
    return lines.join("\n");
}

/**
 * Default canonical path: react-i18n's `package.json` inside the repo.
 * The CLI accepts overrides for both the repo root and the package.json
 * path so test fixtures can drive the script without mutating the real
 * file.
 */
export function defaultPackageJsonPath(repoRoot: string): string {
    return join(
        resolve(repoRoot),
        "packages",
        "react",
        "react-i18n",
        "package.json"
    );
}

async function main(): Promise<void> {
    const argv = process.argv.slice(2);
    let repoRoot = process.cwd();
    let packageJsonPath: string | undefined;
    for (let i = 0; i < argv.length; i += 1) {
        if (argv[i] === "--root" && i + 1 < argv.length) {
            repoRoot = resolve(argv[i + 1] ?? ".");
            i += 1;
            continue;
        }
        if (argv[i] === "--package-json" && i + 1 < argv.length) {
            packageJsonPath = resolve(argv[i + 1] ?? ".");
            i += 1;
        }
    }
    const target = packageJsonPath ?? defaultPackageJsonPath(repoRoot);
    let violations: readonly Violation[];
    try {
        violations = await findViolations({ packageJsonPath: target });
    } catch (cause) {
        process.stderr.write(`${(cause as Error).message}\n`);
        process.exit(2);
    }
    const message = formatViolations(violations);
    if (violations.length === 0) {
        process.stdout.write(`${message}\n`);
        process.exit(0);
    }
    process.stderr.write(`${message}\n`);
    process.exit(1);
}

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