export type WorkspaceItem = {
  id: string;
  label: string;
  path: string;
  kind: 'favorite' | 'view' | 'recent';
  updatedAt: string;
};

type WorkspaceState = {
  favorites: WorkspaceItem[];
  views: WorkspaceItem[];
  recent: WorkspaceItem[];
};

const STORAGE_KEY = 'pulse.operator.workspace.v1';
export const WORKSPACE_EVENT = 'pulse-workspace-changed';

const emptyState = (): WorkspaceState => ({ favorites: [], views: [], recent: [] });

function validItem(value: unknown): value is WorkspaceItem {
  if (!value || typeof value !== 'object') return false;
  const item = value as Partial<WorkspaceItem>;
  return typeof item.id === 'string' && typeof item.label === 'string' && typeof item.path === 'string'
    && ['favorite', 'view', 'recent'].includes(String(item.kind)) && typeof item.updatedAt === 'string';
}

export function readWorkspaceState(): WorkspaceState {
  try {
    const raw = window.localStorage.getItem(STORAGE_KEY);
    if (!raw) return emptyState();
    const parsed = JSON.parse(raw) as Partial<WorkspaceState>;
    return {
      favorites: Array.isArray(parsed.favorites) ? parsed.favorites.filter(validItem).slice(0, 24) : [],
      views: Array.isArray(parsed.views) ? parsed.views.filter(validItem).slice(0, 24) : [],
      recent: Array.isArray(parsed.recent) ? parsed.recent.filter(validItem).slice(0, 12) : [],
    };
  } catch {
    return emptyState();
  }
}

function writeWorkspaceState(state: WorkspaceState): void {
  try {
    window.localStorage.setItem(STORAGE_KEY, JSON.stringify(state));
  } catch {
    return;
  }
  window.dispatchEvent(new CustomEvent(WORKSPACE_EVENT));
}

function timestamp(): string { return new Date().toISOString(); }
function cleanPath(path: string): string {
  if (!path.startsWith('/')) return '/';
  return path.slice(0, 2048);
}
function cleanLabel(label: string): string { return label.trim().slice(0, 160) || 'Pulse'; }

export function isFavorite(path: string): boolean {
  const clean = cleanPath(path);
  return readWorkspaceState().favorites.some((item) => item.path === clean);
}

export function toggleFavorite(label: string, path: string): boolean {
  const state = readWorkspaceState();
  const clean = cleanPath(path);
  const existing = state.favorites.some((item) => item.path === clean);
  const favorite: WorkspaceItem = { id: 'favorite:' + clean, label: cleanLabel(label), path: clean, kind: 'favorite', updatedAt: timestamp() };
  state.favorites = existing
    ? state.favorites.filter((item) => item.path !== clean)
    : [favorite, ...state.favorites].slice(0, 24);
  writeWorkspaceState(state);
  return !existing;
}

export function saveCurrentView(label: string, path: string): void {
  const state = readWorkspaceState();
  const clean = cleanPath(path);
  const item: WorkspaceItem = { id: 'view:' + clean, label: cleanLabel(label), path: clean, kind: 'view', updatedAt: timestamp() };
  state.views = [item, ...state.views.filter((value) => value.path !== clean)].slice(0, 24);
  writeWorkspaceState(state);
}

export function removeSavedView(path: string): void {
  const state = readWorkspaceState();
  const clean = cleanPath(path);
  state.views = state.views.filter((item) => item.path !== clean);
  writeWorkspaceState(state);
}

export function recordRecent(label: string, path: string): void {
  const state = readWorkspaceState();
  const clean = cleanPath(path);
  if (clean === '/404') return;
  const item: WorkspaceItem = { id: 'recent:' + clean, label: cleanLabel(label), path: clean, kind: 'recent', updatedAt: timestamp() };
  state.recent = [item, ...state.recent.filter((value) => value.path !== clean)].slice(0, 12);
  writeWorkspaceState(state);
}