import { create } from "zustand";
import { api } from "../lib/api.ts";

export interface Message {
  id: string;
  channel_id: string;
  author_id: string;
  author_username: string;
  author_display_name: string | null;
  content: string;
  created_at: string;
  edited_at: string | null;
}

interface MessageState {
  messagesByChannel: Record<string, Message[]>;
  isLoading: boolean;
  error: string | null;
  fetchMessages: (channelId: string, before?: string) => Promise<void>;
  sendMessage: (channelId: string, content: string) => Promise<Message>;
  addMessage: (message: Message) => void;
  updateMessage: (message: Message) => void;
  removeMessage: (channelId: string, messageId: string) => void;
}

export const useMessageStore = create<MessageState>((set) => ({
  messagesByChannel: {},
  isLoading: false,
  error: null,

  fetchMessages: async (channelId, before) => {
    set({ isLoading: true, error: null });
    try {
      const params = before ? `?before=${encodeURIComponent(before)}` : "";
      const messages = await api.get<Message[]>(
        `/channels/${channelId}/messages${params}`,
      );
      set((state) => ({
        messagesByChannel: {
          ...state.messagesByChannel,
          [channelId]: Array.isArray(messages) ? messages : [],
        },
        isLoading: false,
      }));
    } catch (error) {
      set({
        isLoading: false,
        error:
          error instanceof Error
            ? error.message
            : "Failed to fetch messages",
      });
    }
  },

  sendMessage: async (channelId, content) => {
    const message = await api.post<Message>(
      `/channels/${channelId}/messages`,
      { content },
    );
    set((state) => {
      const list = state.messagesByChannel[channelId] || [];
      return {
        messagesByChannel: {
          ...state.messagesByChannel,
          [channelId]: [...list, message],
        },
      };
    });
    return message;
  },

  addMessage: (message) =>
    set((state) => {
      const list = state.messagesByChannel[message.channel_id] || [];
      if (list.some((m) => m.id === message.id)) {
        return state;
      }
      return {
        messagesByChannel: {
          ...state.messagesByChannel,
          [message.channel_id]: [...list, message],
        },
      };
    }),

  updateMessage: (message) =>
    set((state) => {
      const list = state.messagesByChannel[message.channel_id] || [];
      return {
        messagesByChannel: {
          ...state.messagesByChannel,
          [message.channel_id]: list.map((m) =>
            m.id === message.id ? message : m,
          ),
        },
      };
    }),

  removeMessage: (channelId, messageId) =>
    set((state) => {
      const list = state.messagesByChannel[channelId] || [];
      return {
        messagesByChannel: {
          ...state.messagesByChannel,
          [channelId]: list.filter((m) => m.id !== messageId),
        },
      };
    }),
}));