export const HOST_BRIDGE_PROTOCOL = 'GenarrativeHostBridge';
export const HOST_BRIDGE_VERSION = 1;

export type HostShellKind = 'browser' | 'wechat_mini_program' | 'native_app';

export type NativeHostShell = 'expo_mobile' | 'tauri_desktop';

export type NativeHostPlatform =
  | 'ios'
  | 'android'
  | 'macos'
  | 'windows'
  | 'linux'
  | 'unknown';

export const HOST_BRIDGE_METHODS = [
  'host.getRuntime',
  'appearance.getColorScheme',
  'auth.requestLogin',
  'payment.request',
  'share.setTarget',
  'share.open',
  'navigation.openNativePage',
  'app.openExternalUrl',
  'app.setTitle',
  'app.setBadgeCount',
  'clipboard.writeText',
  'file.exportText',
  'file.exportImage',
  'haptics.impact',
] as const;

export type HostBridgeMethod = (typeof HOST_BRIDGE_METHODS)[number];

export const HOST_BRIDGE_CAPABILITIES = [
  ...HOST_BRIDGE_METHODS,
  'host.events',
  'navigation.canGoBack',
] as const;

export type HostBridgeCapability = (typeof HOST_BRIDGE_CAPABILITIES)[number];

export function isHostBridgeCapability(
  value: unknown,
): value is HostBridgeCapability {
  return (
    typeof value === 'string' &&
    HOST_BRIDGE_CAPABILITIES.includes(value as HostBridgeCapability)
  );
}

export type HostBridgeRuntimeResult = {
  shell: NativeHostShell;
  platform: NativeHostPlatform;
  hostVersion: string | null;
  bridgeVersion: number;
  capabilities: HostBridgeCapability[];
};

export type HostBridgeRequest<Payload = unknown> = {
  bridge: typeof HOST_BRIDGE_PROTOCOL;
  version: typeof HOST_BRIDGE_VERSION;
  id: string;
  method: HostBridgeMethod;
  payload?: Payload;
  timeoutMs?: number;
};

export type HostBridgeError = {
  code:
    | 'invalid_request'
    | 'unsupported_method'
    | 'unsupported_capability'
    | 'timeout'
    | 'cancelled'
    | 'host_error';
  message: string;
};

export type HostBridgeResponse<Result = unknown> = {
  bridge: typeof HOST_BRIDGE_PROTOCOL;
  version: typeof HOST_BRIDGE_VERSION;
  id: string;
} & (
  | {
      ok: true;
      result?: Result;
    }
  | {
      ok: false;
      error: HostBridgeError;
    }
);

export type HostBridgeEvent<Payload = unknown> = {
  bridge: typeof HOST_BRIDGE_PROTOCOL;
  version: typeof HOST_BRIDGE_VERSION;
  event: string;
  payload?: Payload;
};

export type NavigationCanGoBackEventPayload = {
  canGoBack: boolean;
};

export type HostAppearanceColorScheme = 'light' | 'dark' | 'unknown';

export type AppearanceColorSchemeResult = {
  colorScheme: HostAppearanceColorScheme;
};

export function normalizeHostBridgeColorScheme(
  rawColorScheme: unknown,
): HostAppearanceColorScheme {
  return rawColorScheme === 'light' || rawColorScheme === 'dark'
    ? rawColorScheme
    : 'unknown';
}

export type NavigateNativePagePayload = {
  url: string;
};

export type OpenExternalUrlPayload = {
  url: string;
};

export type SetTitlePayload = {
  title: string;
};

export type SetBadgeCountPayload = {
  count: number;
};

export const HOST_BRIDGE_BADGE_COUNT_MAX = 99999;

export function normalizeHostBridgeBadgeCount(rawCount: unknown) {
  if (
    typeof rawCount !== 'number' ||
    !Number.isInteger(rawCount) ||
    rawCount < 0 ||
    rawCount > HOST_BRIDGE_BADGE_COUNT_MAX
  ) {
    return null;
  }

  return rawCount;
}

export const HOST_BRIDGE_EXTERNAL_URL_PROTOCOLS = [
  'http:',
  'https:',
  'mailto:',
  'tel:',
] as const;

export type HostBridgeExternalUrlProtocol =
  (typeof HOST_BRIDGE_EXTERNAL_URL_PROTOCOLS)[number];

function hasHostBridgeControlCharacter(value: string) {
  return [...value].some((character) => {
    const codePoint = character.codePointAt(0) ?? 0;
    return codePoint <= 31 || codePoint === 127;
  });
}

export function normalizeHostBridgeExternalUrl(rawUrl: unknown) {
  if (typeof rawUrl !== 'string') {
    return null;
  }

  const urlText = rawUrl.trim();
  if (!urlText || hasHostBridgeControlCharacter(urlText)) {
    return null;
  }

  try {
    const url = new URL(urlText);
    if (
      !HOST_BRIDGE_EXTERNAL_URL_PROTOCOLS.includes(
        url.protocol as HostBridgeExternalUrlProtocol,
      )
    ) {
      return null;
    }

    return url.toString();
  } catch {
    return null;
  }
}

export type ClipboardWriteTextPayload = {
  text: string;
};

export type FileExportTextPayload = {
  fileName: string;
  content: string;
  mimeType?: string;
};

export type FileExportTextResult = {
  action: 'saved';
  fileName: string;
  bytes: number;
};

export type FileExportImagePayload = {
  fileName: string;
  base64Data: string;
  mimeType: 'image/png' | 'image/jpeg' | 'image/webp';
};

export type FileExportImageResult = {
  action: 'saved';
  fileName: string;
  bytes: number;
};

export type HapticsImpactPayload = {
  style?: 'light' | 'medium' | 'heavy';
};

export type ShareSetTargetPayload = {
  target: unknown;
};

export type ShareOpenPayload = {
  title?: string;
  message?: string;
  url?: string;
};

const HOST_BRIDGE_FILE_NAME_FALLBACK = 'genarrative-export.txt';
const HOST_BRIDGE_FILE_NAME_MAX_LENGTH = 120;

function isHostBridgeInvalidFileNameCharacter(value: string) {
  if (hasHostBridgeControlCharacter(value)) {
    return true;
  }

  return ['<', '>', ':', '"', '/', '\\', '|', '?', '*'].includes(value);
}

export function normalizeHostBridgeExportFileName(rawFileName: unknown) {
  if (typeof rawFileName !== 'string') {
    return HOST_BRIDGE_FILE_NAME_FALLBACK;
  }

  const fileName = rawFileName
    .trim()
    .split('')
    .map((character) =>
      isHostBridgeInvalidFileNameCharacter(character) ? '-' : character,
    )
    .join('')
    .replace(/\s+/g, ' ')
    .replace(/^[.\s-]+/, '')
    .slice(0, HOST_BRIDGE_FILE_NAME_MAX_LENGTH)
    .trim();

  return fileName || HOST_BRIDGE_FILE_NAME_FALLBACK;
}