/**
 * scaffold-ui-primitives/validate.ts — Args validation.
 */
import { existsSync, statSync } from 'node:fs';
import path from 'node:path';
import { ScaffoldUiPrimitivesInputSchema, type ScaffoldUiPrimitivesInput } from './types.js';
import { readInstalledSmartstackVersion, meetsFloor, MODULE_AVAILABILITY_MIN_VERSION } from './version.js';

export interface ValidationResult {
  valid: boolean;
  spec: ScaffoldUiPrimitivesInput | null;
  errors: string[];
  warnings: string[];
}

export function validate(raw: unknown): ValidationResult {
  const parsed = ScaffoldUiPrimitivesInputSchema.safeParse(raw);
  if (!parsed.success) {
    return {
      valid: false,
      spec: null,
      errors: parsed.error.issues.map((i) => `${i.path.join('.')}: ${i.message}`),
      warnings: [],
    };
  }
  const spec = parsed.data;
  const errors: string[] = [];
  const warnings: string[] = [];

  const abs = path.resolve(spec.projectPath);
  if (!existsSync(abs)) errors.push(`projectPath does not exist: ${abs}`);
  else if (!statSync(abs).isDirectory()) errors.push(`projectPath is not a directory: ${abs}`);
  else if (!existsSync(path.join(abs, 'src'))) {
    warnings.push(`projectPath has no "src" folder yet — it will be created.`);
  }

  // Resolve the package version once, here, so `generate` stays pure. A project below the
  // floor still generates — with a permissive stub — and is TOLD so.
  const resolved: ScaffoldUiPrimitivesInput = {
    ...spec,
    smartstackVersion: spec.smartstackVersion ?? readInstalledSmartstackVersion(spec.projectPath),
  };
  if (errors.length === 0 && !meetsFloor(resolved.smartstackVersion, MODULE_AVAILABILITY_MIN_VERSION)) {
    warnings.push(
      `@atlashub/smartstack ${resolved.smartstackVersion ?? '(not declared)'} predates ${MODULE_AVAILABILITY_MIN_VERSION}: ` +
        `useModuleAvailability is emitted as a PERMISSIVE STUB (every module reads as available, so cross-module ` +
        `related tabs stay visible exactly as before). Run \`ss upgrade\` to activate the tenant-catalogue guard.`,
    );
  }

  return { valid: errors.length === 0, spec: resolved, errors, warnings };
}