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

// ponytail: mirror backend permission bitflags exactly.
export const PERMS = {
  VIEW_CHANNEL: 1,
  SEND_MESSAGES: 2,
  MANAGE_MESSAGES: 4,
  KICK_MEMBERS: 8,
  BAN_MEMBERS: 16,
  MANAGE_SERVER: 32,
  MANAGE_CHANNELS: 64,
  ADMINISTRATOR: 128,
  CONNECT_VOICE: 256,
  SPEAK_VOICE: 512,
  SHARE_SCREEN: 1024,
  MUTE_MEMBERS: 2048,
  CREATE_INSTANT_INVITE: 4096,
  CHANGE_NICKNAME: 8192,
  MANAGE_NICKNAMES: 16384,
  MANAGE_ROLES: 32768,
  MANAGE_WEBHOOKS: 65536,
  EMBED_LINKS: 131072,
  ATTACH_FILES: 262144,
  ADD_REACTIONS: 524288,
  USE_EXTERNAL_EMOJIS: 1048576,
  MENTION_EVERYONE: 2097152,
} as const;

export type PermissionKey = keyof typeof PERMS;

export const PERMISSION_LABELS: Record<PermissionKey, string> = {
  VIEW_CHANNEL: 'View Channel',
  SEND_MESSAGES: 'Send Messages',
  MANAGE_MESSAGES: 'Manage Messages',
  KICK_MEMBERS: 'Kick Members',
  BAN_MEMBERS: 'Ban Members',
  MANAGE_SERVER: 'Manage Server',
  MANAGE_CHANNELS: 'Manage Channels',
  ADMINISTRATOR: 'Administrator',
  CONNECT_VOICE: 'Connect Voice',
  SPEAK_VOICE: 'Speak Voice',
  SHARE_SCREEN: 'Share Screen',
  MUTE_MEMBERS: 'Mute Members',
  CREATE_INSTANT_INVITE: 'Create Instant Invite',
  CHANGE_NICKNAME: 'Change Nickname',
  MANAGE_NICKNAMES: 'Manage Nicknames',
  MANAGE_ROLES: 'Manage Roles',
  MANAGE_WEBHOOKS: 'Manage Webhooks',
  EMBED_LINKS: 'Embed Links',
  ATTACH_FILES: 'Attach Files',
  ADD_REACTIONS: 'Add Reactions',
  USE_EXTERNAL_EMOJIS: 'Use External Emojis',
  MENTION_EVERYONE: 'Mention @everyone',
};

/** Grouped for role/channel permission UIs. ADMINISTRATOR is special-cased in editors. */
export const PERM_CATEGORIES: { name: string; keys: PermissionKey[] }[] = [
  {
    name: 'General',
    keys: [
      'VIEW_CHANNEL',
      'SEND_MESSAGES',
      'MANAGE_MESSAGES',
      'ADD_REACTIONS',
      'EMBED_LINKS',
      'ATTACH_FILES',
      'MENTION_EVERYONE',
      'USE_EXTERNAL_EMOJIS',
      'CREATE_INSTANT_INVITE',
      'CHANGE_NICKNAME',
    ],
  },
  {
    name: 'Moderation',
    keys: ['KICK_MEMBERS', 'BAN_MEMBERS', 'MUTE_MEMBERS', 'MANAGE_NICKNAMES'],
  },
  {
    name: 'Server',
    keys: ['MANAGE_SERVER', 'MANAGE_CHANNELS', 'MANAGE_ROLES', 'MANAGE_WEBHOOKS'],
  },
  {
    name: 'Voice',
    keys: ['CONNECT_VOICE', 'SPEAK_VOICE', 'SHARE_SCREEN'],
  },
];

export function hasPermission(perms: number, flag: number): boolean {
  // Match backend permissions.Has: all required bits must be present.
  return (perms & flag) === flag;
}

export interface ChannelOverride {
  id: string;
  channel_id: string;
  target_type: 'role' | 'user';
  target_id: string;
  allow_bitflags: number;
  deny_bitflags: number;
}

interface PermissionState {
  overridesByChannel: Record<string, ChannelOverride[]>;
  fetchOverrides: (channelId: string) => Promise<void>;
  setOverride: (channelId: string, targetType: 'role' | 'user', targetId: string, allow: number, deny: number) => Promise<ChannelOverride>;
  deleteOverride: (channelId: string, targetType: 'role' | 'user', targetId: string) => Promise<void>;
}

export const usePermissionStore = create<PermissionState>((set) => ({
  overridesByChannel: {},

  fetchOverrides: async (channelId) => {
    const overrides = await api.get<ChannelOverride[]>(`/servers/_/channels/${channelId}/permissions`);
    set((state) => ({
      overridesByChannel: { ...state.overridesByChannel, [channelId]: Array.isArray(overrides) ? overrides : [] },
    }));
  },

  setOverride: async (channelId, targetType, targetId, allow, deny) => {
    const override = await api.put<ChannelOverride>(`/servers/_/channels/${channelId}/permissions/${targetType}/${targetId}`, { allow, deny });
    set((state) => {
      const list = state.overridesByChannel[channelId] || [];
      const filtered = list.filter((o) => !(o.target_type === targetType && o.target_id === targetId));
      return { overridesByChannel: { ...state.overridesByChannel, [channelId]: [...filtered, override] } };
    });
    return override;
  },

  deleteOverride: async (channelId, targetType, targetId) => {
    await api.delete(`/servers/_/channels/${channelId}/permissions/${targetType}/${targetId}`);
    set((state) => {
      const list = state.overridesByChannel[channelId] || [];
      return {
        overridesByChannel: {
          ...state.overridesByChannel,
          [channelId]: list.filter((o) => !(o.target_type === targetType && o.target_id === targetId)),
        },
      };
    });
  },
}));