// Domain model for stamdata maintenance (ADR-0004). Pure TS, no Angular. A table is a
// reflected column schema + editable rows; the pure functions below cover validation
// (FORMAT only — the CI build + StamdataValidationTests stay the authority), the
// valid-time preview filter, the change diff, and serialization back to the file shape.

export type ColumnType = 'text' | 'date' | 'number' | 'enum';

export interface StamColumn {
  name: string;
  type: ColumnType;
  isKey: boolean;
  options: readonly string[];
}

export interface StamTable {
  id: string;
  label: string;
  columns: readonly StamColumn[];
  temporal: boolean;
}

/**
 * An editable row: every cell is the text the user edits ('' = empty). Typed values
 * (number, null geldigTot) are reconstructed at export time — see {@link toJson}.
 */
export type StamRow = Record<string, string>;

export interface ChangeCounts {
  added: number;
  removed: number;
  edited: number;
}

const GELDIG_VAN = 'geldigVan';
const GELDIG_TOT = 'geldigTot';

export function keyColumn(table: StamTable): StamColumn {
  return table.columns.find((c) => c.isKey) ?? table.columns[0];
}

export function keyOf(table: StamTable, row: StamRow): string {
  return row[keyColumn(table).name] ?? '';
}

export function emptyRow(table: StamTable): StamRow {
  const row: StamRow = {};
  for (const c of table.columns) row[c.name] = '';
  return row;
}

/**
 * Valid-time membership, half-open [van, tot) — the same rule the backend applies, done
 * client-side so the editor's "geldig op" preview is instant and never drops unsaved edits.
 * ISO yyyy-MM-dd strings compare correctly lexicographically. Non-temporal tables: all rows.
 */
export function activeOn(table: StamTable, row: StamRow, on: string): boolean {
  if (!table.temporal) return true;
  const van = row[GELDIG_VAN] ?? '';
  const tot = row[GELDIG_TOT] ?? '';
  return van !== '' && van <= on && (tot === '' || on < tot);
}

/** Per-row FORMAT error (index-aligned; '' = valid). Cross-row overlap is the CI gate's job. */
export function rowErrors(table: StamTable, rows: readonly StamRow[]): string[] {
  const key = keyColumn(table).name;
  return rows.map((row) => {
    if ((row[key] ?? '').trim() === '')
      return $localize`:@@beheer.validation.key:Vul de sleutelkolom in.`;
    if (table.temporal) {
      const van = row[GELDIG_VAN] ?? '';
      const tot = row[GELDIG_TOT] ?? '';
      if (van === '') return $localize`:@@beheer.validation.van:Vul een 'geldig van'-datum in.`;
      if (tot !== '' && tot <= van)
        return $localize`:@@beheer.validation.range:'Geldig tot' moet ná 'geldig van' liggen.`;
    }
    return '';
  });
}

export function isValid(table: StamTable, rows: readonly StamRow[]): boolean {
  return rowErrors(table, rows).every((e) => e === '');
}

/** Diff draft against the loaded snapshot, matched by key value. */
export function changeCounts(
  table: StamTable,
  original: readonly StamRow[],
  draft: readonly StamRow[],
): ChangeCounts {
  const origByKey = new Map(original.map((r) => [keyOf(table, r), r]));
  const draftKeys = new Set(draft.map((r) => keyOf(table, r)));
  let added = 0;
  let edited = 0;
  for (const row of draft) {
    const prev = origByKey.get(keyOf(table, row));
    if (!prev) added++;
    else if (!sameRow(table, prev, row)) edited++;
  }
  const removed = original.filter((r) => !draftKeys.has(keyOf(table, r))).length;
  return { added, removed, edited };
}

function sameRow(table: StamTable, a: StamRow, b: StamRow): boolean {
  return table.columns.every((c) => (a[c.name] ?? '') === (b[c.name] ?? ''));
}

/**
 * Serialize the draft back to the data-file's JSON shape, reconstructing typed values per
 * column: an empty date/number cell becomes null (an open-ended geldigTot), a number cell
 * becomes a number, everything else a string. This is the file the admin drops into the
 * repo — the existing CI build re-validates it (a bad edit fails the build, never prod).
 */
export function toJson(table: StamTable, rows: readonly StamRow[]): string {
  const objects = rows.map((row) => {
    const out: Record<string, string | number | null> = {};
    for (const c of table.columns) {
      const cell = (row[c.name] ?? '').trim();
      out[c.name] =
        cell === ''
          ? c.type === 'text' || c.type === 'enum'
            ? ''
            : null
          : c.type === 'number'
            ? Number(cell)
            : cell;
    }
    return out;
  });
  return JSON.stringify(objects, null, 2) + '\n';
}