// #90 Review photo strip (REVIEW-5 / PUBLISH-45). Pure logic split out so the
// keep/remove + reorder + minimum enforcement is unit-testable without a browser.
//
// Model (approved in the wireframe): the owner taps a photo to keep/remove it,
// drags to reorder, and the LEFTMOST kept photo is the primary (Woo cover). The
// submission-ready minimum is at least one clean (calibration) photo AND one
// dimension-overlay copy (REVIEW-5 "clean first pic plus its dimension-overlay
// copy"). Batch photos are optional.

export type PhotoRole = 'calibration' | 'overlay' | 'batch';

export interface LineupItem {
  id: string;
  role: PhotoRole;
  isCalibration: boolean;
  /** True = the owner keeps this photo in the submission. */
  kept: boolean;
}

/**
 * The kept photos in their current (left→right) order. The first kept photo is
 * the primary (Woo cover). Reordering is a plain array move; this helper just
 * exposes the kept subset so the caller can re-seq on persist.
 */
export function keptInOrder(items: LineupItem[]): LineupItem[] {
  return items.filter((it) => it.kept);
}

/** Move an item from one index to another (drag-reorder). Returns a new array. */
export function moveItem<T>(arr: T[], from: number, to: number): T[] {
  if (from === to || from < 0 || to < 0 || from >= arr.length || to >= arr.length) {
    return arr;
  }
  const next = arr.slice();
  const [item] = next.splice(from, 1);
  next.splice(to, 0, item);
  return next;
}

/**
 * Whether the kept lineup meets the submission minimum (REVIEW-5): at least one
 * clean calibration photo and one dimension-overlay copy. Returns the missing
 * role(s) so the UI can name them in a nudge.
 */
export function missingMinimums(items: LineupItem[]): PhotoRole[] {
  const kept = items.filter((it) => it.kept);
  const missing: PhotoRole[] = [];
  if (!kept.some((it) => it.role === 'calibration')) missing.push('calibration');
  if (!kept.some((it) => it.role === 'overlay')) missing.push('overlay');
  return missing;
}

/** True when the kept lineup is publishable from a photo standpoint. */
export function lineupValid(kept: LineupItem[]): boolean {
  return missingMinimums(kept).length === 0;
}

/** A short owner-facing label for a role (used in the minimum nudge). */
export function roleLabel(role: PhotoRole): string {
  if (role === 'calibration') return 'a clean photo';
  if (role === 'overlay') return 'its dimension-overlay copy';
  return 'a batch photo';
}

/**
 * Resolve the <img> src for a strip photo. The in-memory capture blob (fresh
 * photo) must become a `blob:` object URL — assigning a raw Blob (or
 * `String(blob)` = "object Blob") to `src` renders a broken image. That was
 * bug #1: the first/Primary (calibration) photo is the one carrying a blob.
 * When there is no usable blob, fall back to the stored photo endpoint.
 *
 * Pure + injectable: `createObjectUrl` defaults to `URL.createObjectURL` so it
 * is unit-testable without a real DOM/Blob.
 */
export function resolvePhotoUrl(
  blob: Blob | null,
  endpoint: string,
  createObjectUrl: (b: Blob) => string = (b) => URL.createObjectURL(b),
): string {
  if (blob && blob.size > 0) return createObjectUrl(blob);
  return endpoint;
}