import { computed, readonly, ref } from 'vue';
import { isNativeAppState, updateIsBusy } from '@/lib/native-app';
import type { NativeAction, NativeAppState } from '@/types/native-app';

const state = ref<NativeAppState | null>(null);
const pending = ref(false);
const error = ref<string | null>(null);
let initializing = false;
let refreshing: Promise<void> | null = null;

async function request(
    action: NativeAction,
    payload: Record<string, unknown> = {},
) {
    if (typeof window === 'undefined' || window.kanbanNative?.version !== 1) {
        throw new Error('bridgeUnavailable');
    }
    let timer: ReturnType<typeof setTimeout> | undefined;
    try {
        return await Promise.race([
            window.kanbanNative.request(action, payload),
            new Promise<never>((_, reject) => {
                timer = setTimeout(
                    () => reject(new Error('bridgeTimeout')),
                    11000,
                );
            }),
        ]);
    } finally {
        clearTimeout(timer);
    }
}

async function refresh() {
    if (refreshing) {
        return refreshing;
    }
    refreshing = (async () => {
        const result = await request('getState');
        if (!isNativeAppState(result)) {
            throw new Error('incompatibleVersion');
        }
        state.value = result;
    })();
    try {
        await refreshing;
    } finally {
        refreshing = null;
    }
}

export async function initializeNativeApp() {
    if (
        initializing ||
        state.value ||
        typeof window === 'undefined' ||
        window.kanbanNative?.version !== 1
    ) {
        return;
    }
    initializing = true;
    try {
        await refresh();
        await request('settingsReady');
    } catch {
        state.value = null;
    } finally {
        initializing = false;
    }
}

export function useNativeApp() {
    const busy = computed(
        () => pending.value || updateIsBusy(state.value?.updates),
    );
    async function act(
        action: NativeAction,
        payload: Record<string, unknown> = {},
    ) {
        if (
            pending.value ||
            (updateIsBusy(state.value?.updates) && action !== 'openSettings')
        ) {
            return false;
        }
        pending.value = true;
        error.value = null;
        try {
            await request(action, payload);
            if (action !== 'setWorkspace') {
                await refresh();
            }
            return true;
        } catch (cause) {
            error.value =
                cause instanceof Error ? cause.message : 'bridgeUnavailable';
            return false;
        } finally {
            pending.value = false;
        }
    }
    async function poll() {
        try {
            await refresh();
        } catch (cause) {
            error.value =
                cause instanceof Error ? cause.message : 'bridgeUnavailable';
        }
    }
    return { state: readonly(state), busy, error: readonly(error), act, poll };
}

export async function recoverNativeWorkspace() {
    if (!state.value) {
        return;
    }
    try {
        await request('openSettings');
    } catch {
        /* Native recovery remains available from the app menu or toolbar. */
    }
}

export function registerNativeRecovery() {
    window.addEventListener('offline', () => {
        void recoverNativeWorkspace();
    });
    document.addEventListener('inertia:exception', () => {
        void recoverNativeWorkspace();
    });
    document.addEventListener('inertia:invalid', (event) => {
        if (event.detail.response.status >= 400) {
            void recoverNativeWorkspace();
        }
    });
}