/**
 * lib/display-field.ts — SSOT of "which field NAMES a row".
 *
 * Unifies the two heuristics that used to live apart (§26): scaffold-business's
 * pickDisplayField hardcoded ['Name','Label','Code','Title'] while
 * derive-related-tabs-data matched the wider DISPLAYISH family — and the
 * fallback below either list was "first string column", which labelled rows
 * with phone numbers, free comments or raw GUIDs on ten entities of one
 * project. The lists here are the ONLY sanctioned cascade; there is no silent
 * fallback anymore (scaffold-business fails closed, `**Affichage**` in
 * entité.md is the authoring channel, `**Affichage** : Id` the conscious
 * opt-out).
 */

/**
 * Stored-column display candidates, in priority order (PascalCase property
 * names). Same family as DISPLAYISH_RE, ordered by how strongly the name
 * asserts "this labels the row".
 */
export const PREFERRED_DISPLAY_FIELDS: readonly string[] = [
  'Name',
  'Label',
  'Code',
  'Title',
  'Libelle',
  'Titre',
  'Reference',
  'Number',
  'Numero',
]

/**
 * The same cascade MINUS `Code`, for reference tables.
 *
 * A reference value's label IS its identity: on a `lookup`, the code is at
 * best a technical handle and at worst — measured — the thing every combobox
 * and every column ended up showing (`A_FAIRE` instead of « À faire », on 11
 * services fixed BY HAND because the generator kept re-choosing `Code`).
 * Other classifications keep `Code` in the cascade: on an invoice or a
 * contract the code IS the handle people quote over the phone.
 */
export const LOOKUP_DISPLAY_FIELDS: readonly string[] = PREFERRED_DISPLAY_FIELDS.filter(
  (f) => f !== 'Code',
)

/**
 * The stored cascade to use for an entity of this classification. Passing no
 * classification keeps the historical behaviour — the caller simply does not
 * know, and a reference table without its `**Affichage**` line is DM-015's
 * business, not a place to guess.
 */
export function preferredDisplayFieldsFor(classification?: string): readonly string[] {
  const folded = (classification ?? '')
    .normalize('NFD')
    .replace(/[̀-ͯ]/g, '')
    .toLowerCase()
  return folded.includes('lookup') ? LOOKUP_DISPLAY_FIELDS : PREFERRED_DISPLAY_FIELDS
}

/**
 * Core-PROJECTED display candidates (Person entities — the identity lives on
 * auth_Users). `FirstName`+`LastName` both projected compose into a full name
 * BEFORE this list is consulted.
 */
export const PREFERRED_PROJECTED_DISPLAY_FIELDS: readonly string[] = [
  'DisplayName',
  'FullName',
  'Name',
  'Label',
  'Title',
  'LastName',
  'FirstName',
  'Email',
]

/**
 * Case-insensitive "this key labels the row" test for kebab/camel column keys
 * (the derive-related-tabs-data / responsive-table instinct).
 */
export const DISPLAYISH_RE = /^(code|label|name|libelle|title|titre|number|numero|reference)$/i

/**
 * The `- **Affichage** : <Attribut>` line of an entité.md entity block — the
 * BA's authoring channel for "what names a row" (grammar:
 * business-analyse/_workflow/doc-templates.md; `: Id` is the conscious GUID
 * opt-out). First DETERMINISTIC parser of the line: until it, the token was
 * transported by an LLM step only (ba-develop phases-detail Phase 2).
 */
export const DISPLAY_FIELD_LINE_RE = /^-\s*\*\*Affichage\*\*\s*:\s*([A-Za-z][A-Za-z0-9]*)/m

/**
 * Parse the entity-block-scoped `**Affichage**` line of `entité.md`. Scoping
 * mirrors derive-lifecycle's parseEntityStatusEnums (`### `-split + heading
 * word-boundary test) so a sibling entity's line never leaks in. Returns the
 * PascalCase token verbatim — `'Id'` included (callers treat it as the
 * conscious opt-out) — or `null` when the entity block or the line is absent.
 */
export function parseDisplayFieldLine(entiteMd: string, entity: string): string | null {
  const blocks = entiteMd.split(/^###\s+/m)
  const entityRe = new RegExp(`(^|[^A-Za-z0-9])${entity}([^A-Za-z0-9]|$)`)
  const block = blocks.find((b) => entityRe.test(b.split(/\r?\n/, 1)[0] ?? ''))
  if (block === undefined) return null
  const m = DISPLAY_FIELD_LINE_RE.exec(block)
  return m ? m[1]! : null
}