/**
 * cli:split-component-registry — validate.ts
 *
 * Fail-closed gates, in order (pattern of scaffold-pwa/validate.ts):
 *   1. Zod parse (defaults applied).
 *   2. projectPath exists + assertWebProjectRoot (never operate on a backend tree).
 *   3. detectFrontendMode(projectPath) MUST be 'client' — the monolith itself is
 *      a client-mode marker (lib/detector), the socle never carries one.
 *   4. registryFile exists on disk (nothing to split otherwise).
 */
import fs from 'node:fs'
import path from 'node:path'
import { assertWebProjectRoot } from '../../../../../lib/fs.js'
import { detectFrontendMode } from '../../../../../lib/detector.js'
import {
  SplitComponentRegistryInputSchema,
  type SplitComponentRegistryInput,
  type ValidationResult,
} from './types.js'

export async function validate(
  raw: unknown,
): Promise<ValidationResult & { spec?: SplitComponentRegistryInput }> {
  const parsed = SplitComponentRegistryInputSchema.safeParse(raw)
  if (!parsed.success) {
    return {
      valid: false,
      errors: parsed.error.issues.map((i) => `[${i.path.join('.')}] ${i.message}`),
      warnings: [],
    }
  }
  const spec = parsed.data

  try {
    assertWebProjectRoot(spec.projectPath)
  } catch (err) {
    return { valid: false, errors: [err instanceof Error ? err.message : String(err)], warnings: [] }
  }

  const mode = await detectFrontendMode(spec.projectPath)
  if (mode.mode !== 'client') {
    return {
      valid: false,
      errors: [
        `split-component-registry only operates on a CLIENT app (detected mode: '${mode.mode}'). ` +
          `The socle manages its own registry; 'unknown' refuses rather than guesses.`,
      ],
      warnings: [],
    }
  }

  const registryAbs = path.join(spec.projectPath, spec.registryFile)
  if (!fs.existsSync(registryAbs)) {
    return {
      valid: false,
      errors: [`registryFile not found: ${spec.registryFile} (resolved: ${registryAbs}) — nothing to split.`],
      warnings: [],
    }
  }

  return { valid: true, errors: [], warnings: [], spec }
}