import type { MovementDetailKind } from '../data/movement-interior-styles';

/**
 * Even bay centres along the depth axis — same formula as historic `useBayZ`.
 * Pure (no React) so hang layout can reserve the same Z as period columns.
 */
export function bayPositions(depth: number, halfD: number, spacing = 4.2, max = 9): number[] {
  const count = Math.max(2, Math.min(max, Math.floor(depth / spacing)));
  const step = depth / (count + 1);
  return Array.from({ length: count }, (_, i) => -halfD + step * (i + 1));
}

export type SideColumnRhythm = {
  /** Bay spacing passed to bayPositions (matches the period module). */
  spacing: number;
  max: number;
  /**
   * Half-width along the wall (Z) of the keep-out around each bay centre.
   * Covers shaft/base/capital plus a small gap so frames do not kiss the column.
   */
  halfClear: number;
};

/**
 * Mid-wall vertical members that share the hang line on left/right walls.
 * Corner-only orders are omitted — WALL_PADDING already clears the pockets.
 */
export const SIDE_WALL_COLUMN_RHYTHMS = {
  gothic: { spacing: 4.2, max: 9, halfClear: 0.42 },
  roman: { spacing: 4.0, max: 9, halfClear: 0.3 },
  quattrocento: { spacing: 3.8, max: 9, halfClear: 0.34 },
  // Paired pilasters sit at bay±0.19 with r≈0.11
  cinquecento: { spacing: 5.2, max: 6, halfClear: 0.44 },
  mannerist: { spacing: 4.8, max: 6, halfClear: 0.36 },
  neoclassical: { spacing: 4.8, max: 6, halfClear: 0.3 },
  'gothic-revival': { spacing: 3.8, max: 8, halfClear: 0.24 },
  'art-nouveau': { spacing: 3.0, max: 10, halfClear: 0.22 },
} as const satisfies Partial<Record<MovementDetailKind, SideColumnRhythm>>;

export type SideColumnDetailKind = keyof typeof SIDE_WALL_COLUMN_RHYTHMS;

export function sideColumnRhythm(details: MovementDetailKind | undefined): SideColumnRhythm | null {
  if (!details) return null;
  return (SIDE_WALL_COLUMN_RHYTHMS as Partial<Record<MovementDetailKind, SideColumnRhythm>>)[details] ?? null;
}

/** Merged [z0, z1] intervals that side-wall paintings (and windows) must avoid. */
export function sideColumnKeepOutIntervals(
  details: MovementDetailKind | undefined,
  depth: number,
  halfD: number
): [number, number][] {
  const rhythm = sideColumnRhythm(details);
  if (!rhythm) return [];
  return bayPositions(depth, halfD, rhythm.spacing, rhythm.max).map(
    (z) => [z - rhythm.halfClear, z + rhythm.halfClear] as [number, number]
  );
}