/**
 * cli:scaffold-component — render/i18n-files.ts
 * Extracted VERBATIM from the historical generate.ts (pure move — frozen by
 * the 1.0 corpus hash). Renders nothing when the view is absent from
 * spec.views.
 */
import type { GeneratedFile } from '../types.js'
import { LOCALES, Locale, buildTranslations, dropI18nPlaceholders, flatToNested, flattenCatalogue, normalizeI18nFieldKeys } from './shared.js'
import type { RenderContext } from './context.js'

export function renderI18nFiles(rc: RenderContext): GeneratedFile[] {
  const files: GeneratedFile[] = []
  const { spec, ctx, eLower } = rc
  // ─── i18n JSON per locale ────────────────────────────────────────────────
  // The generator ALWAYS emits a COMPLETE floor catalogue (buildTranslations)
  // that mirrors every bare `t('…')` key the templates render — list / detail /
  // form / dashboard / home / kanban / reconduction / breadcrumb. In enriched
  // mode the PRD's business-translated labels (pageSpec.i18nKeys) are layered
  // ON TOP as overrides: the PRD wins where it supplies a key, the floor
  // guarantees no rendered key is ever missing (never a raw key on screen).
  // Without the floor, a thin PRD i18nKeys block leaves structural keys
  // (breadcrumb.section, list.actionsColumn, form.submitCreate, …) untranslated.
  //
  // i18n catalogues land at `src/i18n/locales/{locale}/{module}.json` —
  // module-level (one JSON per module, NOT per entity), matching the
  // SmartStack project layout where i18n config.ts loads namespaces by module.
  //
  // SELF-SUFFICIENT emission: the existing on-disk module catalogue (injected
  // via ctx.existingI18n by index.ts / tests) is folded in HERE, so any
  // verbatim writer produces a correct file. Precedence for THIS entity's
  // subtree:
  //   floor (gap-filler)  <  existing (earlier views' PRD text, manual fixes)
  //                       <  this call's PRD i18nKeys (the authored truth).
  // The floor-below-existing order is what stops the cross-view clobber: the
  // pipeline scaffolds one VIEW per call while buildTranslations is
  // view-agnostic, so without it a later `form` call's floor `list.subtitle`
  // would revert the `list` call's PRD text (AtlasHub PROJECTS/BUDGETS).
  // Sibling entity roots are carried VERBATIM. Keys in `existing` that belong
  // to neither floor nor PRD LINGER on purpose (provenance is unknowable — a
  // manual key rendered by a @customised page must survive); they are inert.
  for (const locale of LOCALES) {
    const floorFlat = flattenCatalogue(buildTranslations(spec, locale as Locale))
    // dropI18nPlaceholders: a `"[en] <fr>"`-style placeholder must never
    // override the floor — dropping it here means the floor's real translation
    // (or humanised label) ships instead of the bracket-tagged raw value.
    const prdFlat = spec.pageSpec
      ? normalizeI18nFieldKeys(dropI18nPlaceholders({ ...(spec.pageSpec.i18nKeys[locale as keyof typeof spec.pageSpec.i18nKeys] ?? {}) }))
      : {}
    const existingModule = ctx.existingI18n?.[locale] ?? {}
    const existingEntity = existingModule[eLower]
    const existingEntityFlat =
      existingEntity !== null && typeof existingEntity === 'object' && !Array.isArray(existingEntity)
        ? flattenCatalogue(existingEntity as Record<string, unknown>)
        : {}
    const i18nFlat = { ...floorFlat, ...existingEntityFlat, ...prdFlat }
    // Wrap under entity key so multiple entities in the same module coexist
    // without collision: { contact: { list: {...} }, company: { list: {...} } }.
    // Spread-override keeps the entity key's original position → stable diffs.
    const payload = { ...existingModule, [eLower]: flatToNested(i18nFlat) }
    files.push({
      path: `src/i18n/locales/${locale}/${spec.module}.json`,
      content: JSON.stringify(payload, null, 2) + '\n',
    })
  }

  return files
}