import {
  OrchestrationEvent,
  ORCHESTRATION_WS_CHANNELS,
  ORCHESTRATION_WS_METHODS,
  type NativeApi,
  ServerConfigUpdatedPayload,
  TerminalEvent,
  WS_CHANNELS,
  WS_METHODS,
  WsWelcomePayload,
} from "@t3tools/contracts";
import { Cause, Schema } from "effect";

import { showContextMenuFallback } from "./contextMenuFallback";
import { WsTransport } from "./wsTransport";

let instance: { api: NativeApi; transport: WsTransport } | null = null;
const welcomeListeners = new Set<(payload: WsWelcomePayload) => void>();
const serverConfigUpdatedListeners = new Set<(payload: ServerConfigUpdatedPayload) => void>();
let lastWelcome: WsWelcomePayload | null = null;
let lastServerConfigUpdated: ServerConfigUpdatedPayload | null = null;

const decodeAndWarnOnFailure = <T>(
  schema: Schema.Schema<T> & { readonly DecodingServices: never },
  raw: unknown,
): T | null => {
  const decoded = Schema.decodeUnknownExit(schema)(raw);
  if (decoded._tag === "Failure") {
    console.warn("Dropped inbound WebSocket push payload", {
      reason: "decode-failed",
      raw,
      issue: Cause.pretty(decoded.cause),
    });
    return null;
  }
  return decoded.value;
};

/**
 * Subscribe to the server welcome message. If a welcome was already received
 * before this call, the listener fires synchronously with the cached payload.
 * This avoids the race between WebSocket connect and React effect registration.
 */
export function onServerWelcome(listener: (payload: WsWelcomePayload) => void): () => void {
  welcomeListeners.add(listener);

  // Replay cached welcome for late subscribers
  if (lastWelcome) {
    try {
      listener(lastWelcome);
    } catch {
      // Swallow listener errors
    }
  }

  return () => {
    welcomeListeners.delete(listener);
  };
}

/**
 * Subscribe to server config update events. Replays the latest update for
 * late subscribers to avoid missing config validation feedback.
 */
export function onServerConfigUpdated(
  listener: (payload: ServerConfigUpdatedPayload) => void,
): () => void {
  serverConfigUpdatedListeners.add(listener);

  if (lastServerConfigUpdated) {
    try {
      listener(lastServerConfigUpdated);
    } catch {
      // Swallow listener errors
    }
  }

  return () => {
    serverConfigUpdatedListeners.delete(listener);
  };
}

export function createWsNativeApi(): NativeApi {
  if (instance) return instance.api;

  const transport = new WsTransport();

  // Listen for server welcome and forward to registered listeners.
  // Also cache it so late subscribers (React effects) get it immediately.
  transport.subscribe(WS_CHANNELS.serverWelcome, (data) => {
    const payload = decodeAndWarnOnFailure(WsWelcomePayload, data);
    if (!payload) return;
    lastWelcome = payload;
    for (const listener of welcomeListeners) {
      try {
        listener(payload);
      } catch {
        // Swallow listener errors
      }
    }
  });
  transport.subscribe(WS_CHANNELS.serverConfigUpdated, (data) => {
    const payload = decodeAndWarnOnFailure(ServerConfigUpdatedPayload, data);
    if (!payload) return;
    lastServerConfigUpdated = payload;
    for (const listener of serverConfigUpdatedListeners) {
      try {
        listener(payload);
      } catch {
        // Swallow listener errors
      }
    }
  });

  const api: NativeApi = {
    dialogs: {
      pickFolder: async () => {
        if (!window.desktopBridge) return null;
        return window.desktopBridge.pickFolder();
      },
      confirm: async (message) => {
        if (window.desktopBridge) {
          return window.desktopBridge.confirm(message);
        }
        return window.confirm(message);
      },
    },
    terminal: {
      open: (input) => transport.request(WS_METHODS.terminalOpen, input),
      write: (input) => transport.request(WS_METHODS.terminalWrite, input),
      resize: (input) => transport.request(WS_METHODS.terminalResize, input),
      clear: (input) => transport.request(WS_METHODS.terminalClear, input),
      restart: (input) => transport.request(WS_METHODS.terminalRestart, input),
      close: (input) => transport.request(WS_METHODS.terminalClose, input),
      onEvent: (callback) =>
        transport.subscribe(WS_CHANNELS.terminalEvent, (data) => {
          const payload = decodeAndWarnOnFailure(TerminalEvent, data);
          if (payload) callback(payload);
        }),
    },
    projects: {
      searchEntries: (input) => transport.request(WS_METHODS.projectsSearchEntries, input),
    },
    shell: {
      openInEditor: (cwd, editor) =>
        transport.request(WS_METHODS.shellOpenInEditor, { cwd, editor }),
      openExternal: async (url) => {
        if (window.desktopBridge) {
          const opened = await window.desktopBridge.openExternal(url);
          if (!opened) {
            throw new Error("Unable to open link.");
          }
          return;
        }

        // Some mobile browsers can return null here even when the tab opens.
        // Avoid false negatives and let the browser handle popup policy.
        window.open(url, "_blank", "noopener,noreferrer");
      },
    },
    git: {
      pull: (input) => transport.request(WS_METHODS.gitPull, input),
      status: (input) => transport.request(WS_METHODS.gitStatus, input),
      runStackedAction: (input) => transport.request(WS_METHODS.gitRunStackedAction, input),
      listBranches: (input) => transport.request(WS_METHODS.gitListBranches, input),
      createWorktree: (input) => transport.request(WS_METHODS.gitCreateWorktree, input),
      removeWorktree: (input) => transport.request(WS_METHODS.gitRemoveWorktree, input),
      createBranch: (input) => transport.request(WS_METHODS.gitCreateBranch, input),
      checkout: (input) => transport.request(WS_METHODS.gitCheckout, input),
      init: (input) => transport.request(WS_METHODS.gitInit, input),
    },
    contextMenu: {
      show: async <T extends string>(
        items: readonly { id: T; label: string }[],
        position?: { x: number; y: number },
      ): Promise<T | null> => {
        if (window.desktopBridge) {
          return window.desktopBridge.showContextMenu(items) as Promise<T | null>;
        }
        return showContextMenuFallback(items, position);
      },
    },
    server: {
      getConfig: () => transport.request(WS_METHODS.serverGetConfig),
      upsertKeybinding: (input) => transport.request(WS_METHODS.serverUpsertKeybinding, input),
    },
    orchestration: {
      getSnapshot: () => transport.request(ORCHESTRATION_WS_METHODS.getSnapshot),
      dispatchCommand: (command) =>
        transport.request(ORCHESTRATION_WS_METHODS.dispatchCommand, { command }),
      getTurnDiff: (input) => transport.request(ORCHESTRATION_WS_METHODS.getTurnDiff, input),
      getFullThreadDiff: (input) =>
        transport.request(ORCHESTRATION_WS_METHODS.getFullThreadDiff, input),
      replayEvents: (fromSequenceExclusive) =>
        transport.request(ORCHESTRATION_WS_METHODS.replayEvents, { fromSequenceExclusive }),
      onDomainEvent: (callback) =>
        transport.subscribe(ORCHESTRATION_WS_CHANNELS.domainEvent, (data) => {
          const payload = decodeAndWarnOnFailure(OrchestrationEvent, data);
          if (payload) callback(payload);
        }),
    },
  };

  instance = { api, transport };
  return api;
}