// Small, isolated persistence for AI Assistant settings — deliberately NOT
// folded into stores/settings-store.ts tonight. That store's export/import
// feature enumerates every field by hand; this is prototype-scope UI state
// (docs/AI-ASSISTANT-CONCEPT.md §12's P0/P5), and migrating it into the
// shared store belongs with whichever phase makes these settings real
// product config rather than a local-AI test harness.
export type AiProvider = 'local' | 'server' | 'public' | 'opencode';

/**
 * A named public-provider configuration (BYOK). Decision 2026-08-05: several
 * of these, not one — different models/providers for different questions,
 * picked case by case at Ask time (see `activeProfileId`). The API key
 * itself lives in `lib/ai/key-store.ts`, keyed by `id`, not here — so a
 * profile's metadata can be listed/edited without ever handling the secret.
 */
export interface AiProviderProfile {
  id: string;
  name: string;
  baseUrl: string;
  model: string;
}

export interface AiLocalSettings {
  provider: AiProvider | null;
  localBaseUrl: string;
  localModel: string | null;
  serverModel: string | null;
  opencodeModel: string | null;
  publicProfiles: AiProviderProfile[];
  /** Which saved profile answers the next question. Not a permanent default —
   *  the "Try it" UI lets this be changed per question. */
  activeProfileId: string | null;
  publicConsentAccepted: boolean;
}

const STORAGE_KEY = 'vncmail:ai:settings';

export const DEFAULT_AI_SETTINGS: AiLocalSettings = {
  provider: null,
  localBaseUrl: 'http://127.0.0.1:11434',
  localModel: null,
  serverModel: null,
  opencodeModel: null,
  publicProfiles: [],
  activeProfileId: null,
  publicConsentAccepted: false,
};

function newProfileId(): string {
  return `profile-${Math.random().toString(36).slice(2, 10)}-${Math.random().toString(36).slice(2, 10)}`;
}

/**
 * `activeProfileId` names either a personal BYOK profile (its own id, as
 * always) or an admin-managed preset (see PublicAiPreset), prefixed so the
 * two id spaces can never collide without adding a second field everywhere
 * that reads/writes activeProfileId.
 */
const PRESET_PREFIX = 'preset:';

export function presetActiveId(presetId: string): string {
  return PRESET_PREFIX + presetId;
}

export function isPresetActiveId(activeId: string | null): boolean {
  return !!activeId && activeId.startsWith(PRESET_PREFIX);
}

export function presetIdFromActiveId(activeId: string | null): string | null {
  return activeId && activeId.startsWith(PRESET_PREFIX) ? activeId.slice(PRESET_PREFIX.length) : null;
}

/** One-time upgrade from the earlier single-profile shape (a bare
 *  publicBaseUrl/publicModel pair) into the profile list, so a browser that
 *  already saved settings before profiles existed doesn't just lose them. */
function migrate(raw: Record<string, unknown>): Partial<AiLocalSettings> {
  if (Array.isArray(raw.publicProfiles)) return raw as Partial<AiLocalSettings>;
  if (typeof raw.publicBaseUrl === 'string' && typeof raw.publicModel === 'string' && raw.publicModel) {
    const id = newProfileId();
    return {
      ...raw,
      publicProfiles: [{ id, name: 'Default', baseUrl: raw.publicBaseUrl, model: raw.publicModel }],
      activeProfileId: id,
    };
  }
  return raw as Partial<AiLocalSettings>;
}

export function loadAiSettings(): AiLocalSettings {
  if (typeof window === 'undefined') return { ...DEFAULT_AI_SETTINGS };
  try {
    const raw = window.localStorage.getItem(STORAGE_KEY);
    if (!raw) return { ...DEFAULT_AI_SETTINGS };
    return { ...DEFAULT_AI_SETTINGS, ...migrate(JSON.parse(raw)) };
  } catch {
    return { ...DEFAULT_AI_SETTINGS };
  }
}

export function saveAiSettings(settings: AiLocalSettings): void {
  if (typeof window === 'undefined') return;
  window.localStorage.setItem(STORAGE_KEY, JSON.stringify(settings));
}

export function createProfile(name: string, baseUrl: string, model: string): AiProviderProfile {
  return { id: newProfileId(), name, baseUrl, model };
}