import type { ClientChatMessage } from "./messages";

export type AssistantChatMessage = {
  role: "user" | "assistant";
  content: string;
  imageUrl?: string;
  toolCalls?: Array<{ name: string; status: number }>;
};

const STORAGE_VERSION = "v2";
const MAX_MESSAGES = 40;

function storageKey(userId: string) {
  return `assistant-chat:${STORAGE_VERSION}:${userId}`;
}

function isValidMessage(value: unknown): value is AssistantChatMessage {
  if (!value || typeof value !== "object") return false;
  const row = value as Record<string, unknown>;
  if (row.role !== "user" && row.role !== "assistant") return false;
  if (typeof row.content !== "string" || row.content.trim().length === 0) return false;
  if (row.imageUrl !== undefined && typeof row.imageUrl !== "string") return false;
  if (row.toolCalls !== undefined) {
    if (!Array.isArray(row.toolCalls)) return false;
    for (const call of row.toolCalls) {
      if (!call || typeof call !== "object") return false;
      const entry = call as Record<string, unknown>;
      if (typeof entry.name !== "string" || typeof entry.status !== "number") return false;
    }
  }
  return true;
}

export function toClientChatMessage(message: AssistantChatMessage): ClientChatMessage {
  if (!message.imageUrl) {
    return { role: message.role, content: message.content };
  }

  return {
    role: message.role,
    content: message.content,
    attachments: [{ type: "image", url: message.imageUrl }],
  };
}

export function loadAssistantChat(userId: string): AssistantChatMessage[] {
  try {
    const raw = localStorage.getItem(storageKey(userId));
    if (!raw) return [];
    const parsed: unknown = JSON.parse(raw);
    if (!Array.isArray(parsed)) return [];
    return parsed.filter(isValidMessage).slice(-MAX_MESSAGES);
  } catch {
    return [];
  }
}

export function saveAssistantChat(userId: string, messages: AssistantChatMessage[]): void {
  try {
    const trimmed = messages.slice(-MAX_MESSAGES);
    if (trimmed.length === 0) {
      localStorage.removeItem(storageKey(userId));
      return;
    }
    localStorage.setItem(storageKey(userId), JSON.stringify(trimmed));
  } catch {
    // Private browsing, quota exceeded, or disabled storage.
  }
}

export function clearAssistantChat(userId: string): void {
  try {
    localStorage.removeItem(storageKey(userId));
  } catch {
    // Ignore storage errors.
  }
}