/**
 * cli:derive-lookup-grants — validate.ts
 *
 * Spec validation + prerequisite checks. The derivation is only meaningful
 * once BOTH upstream phases exist for the consumer module: the RBAC matrix
 * (phase 5 — grantees come from its create/update rows) and the data model
 * (phase 6 — FKs come from entité.md). A missing/placeholder prerequisite is
 * a hard error, not an empty block: an empty machine block must mean "the
 * derivation ran and found nothing", never "the inputs were absent".
 */
import { existsSync, readFileSync } from 'node:fs'
import { isAbsolute, join } from 'node:path'
import { isPlaceholderEntityDoc } from '../../../../lib/ba-placeholder.js'
import { DeriveLookupGrantsInputSchema, type ValidationResult } from './types.js'

export function validateSpec(raw: unknown, workdir?: string): ValidationResult {
  const parsed = DeriveLookupGrantsInputSchema.safeParse(raw)
  if (!parsed.success) {
    return {
      valid: false,
      errors: parsed.error.issues.map((i) => `[${i.path.join('.')}] ${i.message}`),
      warnings: [],
    }
  }

  const spec = parsed.data
  const resolvedBaRoot = isAbsolute(spec.baRoot)
    ? spec.baRoot
    : join(workdir ?? process.cwd(), spec.baRoot)

  const errors: string[] = []
  const moduleDir = join(resolvedBaRoot, spec.app, spec.module)
  if (!existsSync(moduleDir)) {
    errors.push(`Consumer module folder not found: ${moduleDir}`)
  } else {
    const rbacPath = join(moduleDir, 'rbac.md')
    if (!existsSync(rbacPath)) {
      errors.push(
        `${spec.app}/${spec.module}/rbac.md not found — run /ba-create-rbac (phase 5) before deriving lookup grants.`,
      )
    }
    const entitePath = join(moduleDir, 'entité.md')
    if (!existsSync(entitePath)) {
      errors.push(
        `${spec.app}/${spec.module}/entité.md not found — run /ba-create-data-model (phase 6) before deriving lookup grants.`,
      )
    } else {
      try {
        // No entity block at all — never a marker test on the whole file, which
        // refused an authored model over one leftover line (lib/ba-placeholder).
        if (isPlaceholderEntityDoc(readFileSync(entitePath, 'utf8'))) {
          errors.push(
            `${spec.app}/${spec.module}/entité.md is still a placeholder — author the data model (phase 6) first.`,
          )
        }
      } catch {
        errors.push(`Cannot read ${entitePath}`)
      }
    }
  }

  return { valid: errors.length === 0, errors, warnings: [], spec, resolvedBaRoot }
}