/**
 * cli:audit-ba — validate.ts
 *
 * Spec validation + prerequisites: the BA root must exist and contain at
 * least one application folder — an empty report must mean « corpus vide »,
 * never « chemin faux ».
 */
import { existsSync, readdirSync, statSync } from 'node:fs'
import { isAbsolute, join } from 'node:path'
import { AuditBaInputSchema, type AuditBaInput } from './types.js'

export interface ValidationResult {
  valid: boolean
  errors: string[]
  spec?: AuditBaInput
  resolvedBaRoot?: string
  resolvedProjectRoot?: string
}

export function validateSpec(raw: unknown, workdir?: string): ValidationResult {
  const parsed = AuditBaInputSchema.safeParse(raw)
  if (!parsed.success) {
    return { valid: false, errors: parsed.error.issues.map((i) => `[${i.path.join('.')}] ${i.message}`) }
  }
  const spec = parsed.data
  const base = workdir ?? process.cwd()
  const resolvedBaRoot = isAbsolute(spec.baRoot) ? spec.baRoot : join(base, spec.baRoot)
  const errors: string[] = []
  if (!existsSync(resolvedBaRoot)) {
    errors.push(`BA root not found: ${resolvedBaRoot}`)
    return { valid: false, errors, spec }
  }
  try {
    const hasApp = readdirSync(resolvedBaRoot, { withFileTypes: true }).some(
      (e) => e.isDirectory() && !e.name.startsWith('_') && !e.name.startsWith('.'),
    )
    if (!hasApp) errors.push(`BA root has no application folder: ${resolvedBaRoot} — run /ba-create-menu first.`)
  } catch {
    errors.push(`BA root is not readable: ${resolvedBaRoot}`)
  }
  let resolvedProjectRoot: string | undefined
  if (spec.projectRoot !== undefined) {
    resolvedProjectRoot = isAbsolute(spec.projectRoot) ? spec.projectRoot : join(base, spec.projectRoot)
    try {
      if (!existsSync(resolvedProjectRoot) || !statSync(resolvedProjectRoot).isDirectory()) {
        errors.push(`projectRoot is not a directory: ${resolvedProjectRoot}`)
      }
    } catch {
      errors.push(`projectRoot is not readable: ${resolvedProjectRoot}`)
    }
  }
  return {
    valid: errors.length === 0,
    errors,
    spec,
    resolvedBaRoot,
    ...(resolvedProjectRoot !== undefined ? { resolvedProjectRoot } : {}),
  }
}