use crate::msg::*;

use btlib::{crypto::Creds, BlockMeta, BlockPath, Result};
use btmsg::{receiver, MsgCallback, MsgReceived, Receiver};
use core::future::Future;
use std::{net::IpAddr, sync::Arc};
use tokio::runtime::Handle as RuntimeHandle;

pub trait FsProvider {
    type LookupFut<'c>: Send + Future<Output = Result<LookupReply>>
    where
        Self: 'c;
    fn lookup<'c>(&'c self, from: &'c Arc<BlockPath>, msg: Lookup<'c>) -> Self::LookupFut<'c>;

    type CreateFut<'c>: Send + Future<Output = Result<CreateReply>>
    where
        Self: 'c;
    fn create<'c>(&'c self, from: &'c Arc<BlockPath>, msg: Create<'c>) -> Self::CreateFut<'c>;

    type OpenFut<'c>: Send + Future<Output = Result<OpenReply>>
    where
        Self: 'c;
    fn open<'c>(&'c self, from: &'c Arc<BlockPath>, msg: Open) -> Self::OpenFut<'c>;

    fn read<'c, R, F>(&'c self, from: &'c Arc<BlockPath>, msg: Read, callback: F) -> Result<R>
    where
        F: 'c + Send + FnOnce(&[u8]) -> R;

    type WriteFut<'c>: Send + Future<Output = Result<WriteReply>>
    where
        Self: 'c;
    fn write<'c>(&'c self, from: &'c Arc<BlockPath>, msg: Write) -> Self::WriteFut<'c>;

    type FlushFut<'c>: Send + Future<Output = Result<()>>
    where
        Self: 'c;
    fn flush<'c>(&'c self, from: &'c Arc<BlockPath>, msg: Flush) -> Self::FlushFut<'c>;

    type ReadDirFut<'c>: Send + Future<Output = Result<ReadDirReply>>
    where
        Self: 'c;
    fn read_dir<'c>(&'c self, from: &'c Arc<BlockPath>, msg: ReadDir) -> Self::ReadDirFut<'c>;

    type LinkFut<'c>: Send + Future<Output = Result<()>>
    where
        Self: 'c;
    fn link<'c>(&'c self, from: &'c Arc<BlockPath>, msg: Link) -> Self::LinkFut<'c>;

    type UnlinkFut<'c>: Send + Future<Output = Result<()>>
    where
        Self: 'c;
    fn unlink<'c>(&'c self, from: &'c Arc<BlockPath>, msg: Unlink) -> Self::UnlinkFut<'c>;

    type ReadMetaFut<'c>: Send + Future<Output = Result<BlockMeta>>
    where
        Self: 'c;
    fn read_meta<'c>(&'c self, from: &'c Arc<BlockPath>, msg: ReadMeta) -> Self::ReadMetaFut<'c>;

    type WriteMetaFut<'c>: Send + Future<Output = Result<()>>
    where
        Self: 'c;
    fn write_meta<'c>(&'c self, from: &'c Arc<BlockPath>, msg: WriteMeta)
        -> Self::WriteMetaFut<'c>;

    type CloseFut<'c>: Send + Future<Output = Result<()>>
    where
        Self: 'c;
    fn close<'c>(&'c self, from: &'c Arc<BlockPath>, msg: Close) -> Self::CloseFut<'c>;

    type ForgetFut<'c>: Send + Future<Output = Result<()>>
    where
        Self: 'c;
    fn forget<'c>(&'c self, from: &'c Arc<BlockPath>, msg: Forget) -> Self::ForgetFut<'c>;

    type LockFut<'c>: Send + Future<Output = Result<()>>
    where
        Self: 'c;
    fn lock<'c>(&'c self, from: &'c Arc<BlockPath>, msg: Lock) -> Self::LockFut<'c>;

    type UnlockFut<'c>: Send + Future<Output = Result<()>>
    where
        Self: 'c;
    fn unlock<'c>(&'c self, from: &'c Arc<BlockPath>, msg: Unlock) -> Self::UnlockFut<'c>;
}

struct ServerCallback<P> {
    provider: Arc<P>,
}

impl<P> ServerCallback<P> {
    fn new(provider: Arc<P>) -> Self {
        Self { provider }
    }
}

impl<P> Clone for ServerCallback<P> {
    fn clone(&self) -> Self {
        Self {
            provider: self.provider.clone(),
        }
    }
}

impl<P: 'static + Send + Sync + FsProvider> MsgCallback for ServerCallback<P> {
    type Arg<'de> = FsMsg<'de>;
    type CallFut<'de> = impl 'de + Future<Output = btlib::Result<()>>;
    fn call<'de>(&'de self, arg: MsgReceived<FsMsg<'de>>) -> Self::CallFut<'de> {
        async move {
            let (from, body, replier) = arg.into_parts();
            let provider = &self.provider;
            let reply = match body {
                FsMsg::Lookup(lookup) => FsReply::Lookup(provider.lookup(&from, lookup).await?),
                FsMsg::Create(create) => FsReply::Create(provider.create(&from, create).await?),
                FsMsg::Open(open) => FsReply::Open(provider.open(&from, open).await?),
                FsMsg::Read(read) => {
                    return provider.read(&from, read, move |data| {
                        let mut replier = replier.unwrap();
                        RuntimeHandle::current()
                            .block_on(replier.reply(FsReply::Read(ReadReply { data })))
                    })?;
                }
                FsMsg::Write(write) => FsReply::Write(provider.write(&from, write).await?),
                FsMsg::Flush(flush) => FsReply::Ack(provider.flush(&from, flush).await?),
                FsMsg::ReadDir(read_dir) => {
                    FsReply::ReadDir(provider.read_dir(&from, read_dir).await?)
                }
                FsMsg::Link(link) => FsReply::Ack(provider.link(&from, link).await?),
                FsMsg::Unlink(unlink) => FsReply::Ack(provider.unlink(&from, unlink).await?),
                FsMsg::ReadMeta(read_meta) => {
                    FsReply::ReadMeta(provider.read_meta(&from, read_meta).await?)
                }
                FsMsg::WriteMeta(write_meta) => {
                    FsReply::Ack(provider.write_meta(&from, write_meta).await?)
                }
                FsMsg::Close(close) => FsReply::Ack(provider.close(&from, close).await?),
                FsMsg::Forget(forget) => FsReply::Ack(provider.forget(&from, forget).await?),
                FsMsg::Lock(lock) => FsReply::Ack(provider.lock(&from, lock).await?),
                FsMsg::Unlock(unlock) => FsReply::Ack(provider.unlock(&from, unlock).await?),
            };
            replier.unwrap().reply(reply).await
        }
    }
}

pub fn new_fs_server<C, P>(
    ip_addr: IpAddr,
    creds: Arc<C>,
    provider: Arc<P>,
) -> Result<impl Receiver>
where
    C: 'static + Send + Sync + Creds,
    P: 'static + Send + Sync + FsProvider,
{
    receiver(ip_addr, creds, ServerCallback::new(provider))
}