use std::{
    collections::{HashMap, HashSet},
    env,
    fmt::Debug,
    fs,
    io::{Read, Write},
    net::SocketAddr,
    path::PathBuf,
    str::FromStr,
    sync::{atomic::AtomicU32, Arc, Mutex, MutexGuard, OnceLock},
};

use bitcoincore_rpc::{
    bitcoin::secp256k1::SecretKey,
    json::{self as bitcoin_json},
};
use commit::{lock_members, MEMBERLIST};
use futures_util::{future, pin_mut, stream::TryStreamExt, FutureExt, StreamExt};
use log::{debug, error, warn};
use message::{broadcast_message, process_message, BroadcastType, MessageCache, MESSAGECACHE};
use scan::{check_transaction_alone, compute_partial_tweak_to_transaction};
use sdk_common::network::{AnkFlag, NewTxMessage};
use sdk_common::{
    network::HandshakeMessage,
    pcd::Member,
    process::{lock_processes, Process, CACHEDPROCESSES},
    serialization::{OutPointMemberMap, OutPointProcessMap},
    silentpayments::SpWallet,
    sp_client::{
        bitcoin::{
            consensus::deserialize,
            hex::{DisplayHex, FromHex},
            Amount, Network, Transaction,
        },
        silentpayments::SilentPaymentAddress,
    },
    MutexExt,
};
use sdk_common::{
    sp_client::{
        bitcoin::{secp256k1::rand::thread_rng, OutPoint},
        SpClient, SpendKey,
    },
    updates::{init_update_sink, NativeUpdateSink, StateUpdate},
};

use serde_json::Value;
use tokio::net::{TcpListener, TcpStream};
use tokio::sync::mpsc::{unbounded_channel, UnboundedSender};
use tokio_stream::wrappers::UnboundedReceiverStream;
use tokio_tungstenite::tungstenite::Message;

use anyhow::{Error, Result};
use zeromq::{Socket, SocketRecv};

mod commit;
mod config;
mod daemon;
mod faucet;
mod message;
mod scan;

use crate::config::Config;
use crate::{
    daemon::{Daemon, RpcCall},
    scan::scan_blocks,
};

pub const WITH_CUTTHROUGH: bool = false; // We'd rather catch everything for this use case

type Tx = UnboundedSender<Message>;

type PeerMap = Mutex<HashMap<SocketAddr, Tx>>;

pub(crate) static PEERMAP: OnceLock<PeerMap> = OnceLock::new();

pub(crate) static DAEMON: OnceLock<Mutex<Box<dyn RpcCall>>> = OnceLock::new();

static CHAIN_TIP: AtomicU32 = AtomicU32::new(0);

pub static FREEZED_UTXOS: OnceLock<Mutex<HashSet<OutPoint>>> = OnceLock::new();

pub fn lock_freezed_utxos() -> Result<MutexGuard<'static, HashSet<OutPoint>>, Error> {
    FREEZED_UTXOS
        .get_or_init(|| Mutex::new(HashSet::new()))
        .lock_anyhow()
}

#[derive(Debug)]
pub struct StateFile {
    path: PathBuf,
}

impl StateFile {
    fn new(path: PathBuf) -> Self {
        Self { path }
    }

    fn create(&self) -> Result<()> {
        let parent: PathBuf;
        if let Some(dir) = self.path.parent() {
            if !dir.ends_with(".4nk") {
                return Err(Error::msg("parent dir must be \".4nk\""));
            }
            parent = dir.to_path_buf();
        } else {
            return Err(Error::msg("wallet file has no parent dir"));
        }

        // Ensure the parent directory exists
        if !parent.exists() {
            fs::create_dir_all(parent)?;
        }

        // Create a new file
        fs::File::create(&self.path)?;

        Ok(())
    }

    fn save(&self, json: &Value) -> Result<()> {
        let mut f = fs::File::options()
            .write(true)
            .truncate(true)
            .open(&self.path)?;

        let stringified = serde_json::to_string(&json)?;
        let bin = stringified.as_bytes();
        f.write_all(bin)?;

        Ok(())
    }

    fn load(&self) -> Result<Value> {
        let mut f = fs::File::open(&self.path)?;

        let mut content = vec![];
        f.read_to_end(&mut content)?;

        let res: Value = serde_json::from_slice(&content)?;

        Ok(res)
    }
}

#[derive(Debug)]
pub struct DiskStorage {
    pub wallet_file: StateFile,
    pub processes_file: StateFile,
    pub members_file: StateFile,
}

pub static STORAGE: OnceLock<Mutex<DiskStorage>> = OnceLock::new();

const FAUCET_AMT: Amount = Amount::from_sat(10_000);

pub(crate) static WALLET: OnceLock<Mutex<SpWallet>> = OnceLock::new();

fn handle_new_tx_request(new_tx_msg: &NewTxMessage) -> Result<()> {
    let tx = deserialize::<Transaction>(&Vec::from_hex(&new_tx_msg.transaction)?)?;

    let daemon = DAEMON.get().unwrap().lock_anyhow()?;
    daemon.test_mempool_accept(&tx)?;
    daemon.broadcast(&tx)?;

    Ok(())
}

async fn handle_connection(
    raw_stream: TcpStream,
    addr: SocketAddr,
    our_sp_address: SilentPaymentAddress,
) {
    debug!("Incoming TCP connection from: {}", addr);

    let peers = PEERMAP.get().expect("Peer Map not initialized");

    let ws_stream = match tokio_tungstenite::accept_async(raw_stream).await {
        Ok(stream) => {
            debug!("WebSocket connection established");
            stream
        }
        Err(e) => {
            log::error!("WebSocket handshake failed for {}: {}", addr, e);
            return;
        }
    };

    // Insert the write part of this peer to the peer map.
    let (tx, rx) = unbounded_channel();
    match peers.lock_anyhow() {
        Ok(mut peer_map) => peer_map.insert(addr, tx),
        Err(e) => {
            log::error!("{}", e);
            panic!();
        }
    };

    let processes = lock_processes().unwrap().clone();
    let members = lock_members().unwrap().clone();
    let current_tip = CHAIN_TIP.load(std::sync::atomic::Ordering::SeqCst);

    let init_msg = HandshakeMessage::new(
        our_sp_address.to_string(),
        OutPointMemberMap(members),
        OutPointProcessMap(processes),
        current_tip.into(),
    );

    if let Err(e) = broadcast_message(
        AnkFlag::Handshake,
        format!("{}", init_msg.to_string()),
        BroadcastType::Sender(addr),
    ) {
        log::error!("Failed to send init message: {}", e);
        return;
    }

    let (outgoing, incoming) = ws_stream.split();

    let broadcast_incoming = incoming.try_for_each(|msg| {
        if let Ok(raw_msg) = msg.to_text() {
            // debug!("Received msg: {}", raw_msg);
            process_message(raw_msg, addr);
        } else {
            debug!("Received non-text message {} from peer {}", msg, addr);
        }
        future::ok(())
    });

    let receive_from_others = UnboundedReceiverStream::new(rx)
        .map(Ok)
        .forward(outgoing)
        .map(|result| {
            if let Err(e) = result {
                debug!("Error sending message: {}", e);
            }
        });

    pin_mut!(broadcast_incoming, receive_from_others);
    future::select(broadcast_incoming, receive_from_others).await;

    debug!("{} disconnected", &addr);
    peers.lock().unwrap().remove(&addr);
}

fn create_new_tx_message(transaction: Vec<u8>) -> Result<NewTxMessage> {
    let tx: Transaction = deserialize(&transaction)?;

    if tx.is_coinbase() {
        return Err(Error::msg("Can't process coinbase transaction"));
    }

    let partial_tweak = compute_partial_tweak_to_transaction(&tx)?;

    let sp_wallet = WALLET
        .get()
        .ok_or_else(|| Error::msg("Wallet not initialized"))?
        .lock_anyhow()?;
    check_transaction_alone(sp_wallet, &tx, &partial_tweak)?;

    Ok(NewTxMessage::new(
        transaction.to_lower_hex_string(),
        Some(partial_tweak.to_string()),
    ))
}

async fn handle_scan_updates(
    scan_rx: std::sync::mpsc::Receiver<sdk_common::updates::ScanProgress>,
) {
    while let Ok(update) = scan_rx.recv() {
        log::debug!("Received scan update: {:?}", update);
    }
}

async fn handle_state_updates(
    state_rx: std::sync::mpsc::Receiver<sdk_common::updates::StateUpdate>,
) {
    while let Ok(update) = state_rx.recv() {
        match update {
            StateUpdate::Update {
                blkheight,
                blkhash,
                found_outputs,
                found_inputs,
            } => {
                // We update the wallet with found outputs and inputs
                let mut sp_wallet = WALLET.get().unwrap().lock_anyhow().unwrap();
                // inputs first
                for outpoint in found_inputs {
                    sp_wallet.mark_output_mined(&outpoint, blkhash);
                }
                sp_wallet.get_mut_outputs().extend(found_outputs);
                sp_wallet.set_last_scan(blkheight.to_consensus_u32());
                let json = serde_json::to_value(sp_wallet.clone()).unwrap();
                STORAGE
                    .get()
                    .unwrap()
                    .lock_anyhow()
                    .unwrap()
                    .wallet_file
                    .save(&json)
                    .unwrap();
            }
            StateUpdate::NoUpdate { blkheight } => {
                // We just keep the current height to update the last_scan
                debug!("No update, setting last scan at {}", blkheight);
                let mut sp_wallet = WALLET.get().unwrap().lock_anyhow().unwrap();
                sp_wallet.set_last_scan(blkheight.to_consensus_u32());
                let json = serde_json::to_value(sp_wallet.clone()).unwrap();
                STORAGE
                    .get()
                    .unwrap()
                    .lock_anyhow()
                    .unwrap()
                    .wallet_file
                    .save(&json)
                    .unwrap();
            }
        }
    }
}

async fn handle_zmq(zmq_url: String, blindbit_url: String) {
    debug!("Starting listening on Core");
    let mut socket = zeromq::SubSocket::new();
    socket.connect(&zmq_url).await.unwrap();
    socket.subscribe("rawtx").await.unwrap();
    socket.subscribe("hashblock").await.unwrap();
    loop {
        let core_msg = match socket.recv().await {
            Ok(m) => m,
            Err(e) => {
                error!("Zmq error: {}", e);
                continue;
            }
        };
        debug!("Received a message");

        let payload: String = if let (Some(topic), Some(data)) = (core_msg.get(0), core_msg.get(1))
        {
            debug!("topic: {}", std::str::from_utf8(&topic).unwrap());
            match std::str::from_utf8(&topic) {
                Ok("rawtx") => match create_new_tx_message(data.to_vec()) {
                    Ok(m) => {
                        debug!("Created message");
                        serde_json::to_string(&m).expect("This shouldn't fail")
                    }
                    Err(e) => {
                        error!("{}", e);
                        continue;
                    }
                },
                Ok("hashblock") => {
                    let current_height = DAEMON
                        .get()
                        .unwrap()
                        .lock_anyhow()
                        .unwrap()
                        .get_current_height()
                        .unwrap();
                    CHAIN_TIP.store(current_height as u32, std::sync::atomic::Ordering::SeqCst);

                    // Add retry logic for hashblock processing
                    let mut retry_count = 0;
                    const MAX_RETRIES: u32 = 4;
                    const RETRY_DELAY_MS: u64 = 1000; // 1 second initial delay

                    loop {
                        match scan_blocks(0, &blindbit_url).await {
                            Ok(_) => {
                                debug!("Successfully scanned blocks after {} retries", retry_count);
                                break;
                            }
                            Err(e) => {
                                retry_count += 1;
                                if retry_count >= MAX_RETRIES {
                                    error!(
                                        "Failed to scan blocks after {} retries: {}",
                                        MAX_RETRIES, e
                                    );
                                    break;
                                }

                                // Exponential backoff: 1s, 2s, 4s
                                let delay_ms = RETRY_DELAY_MS * (1 << (retry_count - 1));
                                warn!(
                                    "Scan failed (attempt {}/{}), retrying in {}ms: {}",
                                    retry_count, MAX_RETRIES, delay_ms, e
                                );

                                tokio::time::sleep(tokio::time::Duration::from_millis(delay_ms))
                                    .await;
                            }
                        }
                    }
                    continue;
                }
                _ => {
                    error!("Unexpected message in zmq");
                    continue;
                }
            }
        } else {
            error!("Empty message");
            continue;
        };

        if let Err(e) = broadcast_message(AnkFlag::NewTx, payload, BroadcastType::ToAll) {
            log::error!("{}", e.to_string());
        }
    }
}

#[tokio::main(flavor = "multi_thread")]
async fn main() -> Result<()> {
    env_logger::init();

    // todo: take the path to conf file as argument
    // default to "./.conf"
    let config = Config::read_from_file(".conf")?;

    if config.network == Network::Bitcoin {
        warn!("Running on mainnet, you're on your own");
    }

    MESSAGECACHE
        .set(MessageCache::new())
        .expect("Message Cache initialization failed");

    PEERMAP
        .set(PeerMap::new(HashMap::new()))
        .expect("PeerMap initialization failed");

        // Connect the rpc daemon with retry logic
    let mut retry_count = 0;
    const MAX_RETRIES: u32 = 5;
    const RETRY_DELAY_MS: u64 = 2000; // 2 seconds initial delay
    
    let daemon = loop {
        let cookie_path = config.cookie_path.as_ref().map(|p| PathBuf::from(p));
        match Daemon::connect(
            config.core_wallet.clone(),
            config.core_url.clone(),
            config.network,
            cookie_path,
        ) {
            Ok(daemon) => break daemon,
            Err(e) => {
                retry_count += 1;
                if retry_count >= MAX_RETRIES {
                    return Err(e.context("Failed to connect to Bitcoin Core after multiple attempts"));
                }
                log::warn!("Failed to connect to Bitcoin Core (attempt {}/{}): {}", retry_count, MAX_RETRIES, e);
                std::thread::sleep(std::time::Duration::from_millis(RETRY_DELAY_MS * retry_count as u64));
            }
        }
    };
    
    DAEMON
        .set(Mutex::new(Box::new(daemon)))
        .expect("DAEMON initialization failed");

    let current_tip: u32 = DAEMON
        .get()
        .unwrap()
        .lock_anyhow()?
        .get_current_height()?
        .try_into()?;

    // Set CHAIN_TIP
    CHAIN_TIP.store(current_tip, std::sync::atomic::Ordering::SeqCst);

    let mut app_dir = PathBuf::from_str(&env::var("HOME")?)?;
    app_dir.push(config.data_dir);
    let mut wallet_file = app_dir.clone();
    wallet_file.push(&config.wallet_name);
    let mut processes_file = app_dir.clone();
    processes_file.push("processes");
    let mut members_file = app_dir.clone();
    members_file.push("members");

    let wallet_file = StateFile::new(wallet_file);
    let processes_file = StateFile::new(processes_file);
    let members_file = StateFile::new(members_file);

    // load an existing sp_wallet, or create a new one
    let sp_wallet: SpWallet = match wallet_file.load() {
        Ok(wallet) => {
            // TODO: Verify the wallet is compatible with the current network
            serde_json::from_value(wallet)?
        }
        Err(_) => {
            // Create a new wallet file if it doesn't exist or fails to load
            wallet_file.create()?;

            let mut rng = thread_rng();

            let new_client = SpClient::new(
                SecretKey::new(&mut rng),
                SpendKey::Secret(SecretKey::new(&mut rng)),
                config.network,
            )
            .expect("Failed to create a new SpClient");

            let mut sp_wallet = SpWallet::new(new_client);

            // Set birthday and update scan information
            sp_wallet.set_birthday(current_tip);
            sp_wallet.set_last_scan(current_tip);

            // Save the newly created wallet to disk
            let json = serde_json::to_value(sp_wallet.clone())?;
            wallet_file.save(&json)?;

            sp_wallet
        }
    };

    let cached_processes: HashMap<OutPoint, Process> = match processes_file.load() {
        Ok(processes) => {
            let deserialized: OutPointProcessMap = serde_json::from_value(processes)?;
            deserialized.0
        }
        Err(_) => {
            debug!("creating process file at {}", processes_file.path.display());
            processes_file.create()?;

            HashMap::new()
        }
    };

    let members: HashMap<OutPoint, Member> = match members_file.load() {
        Ok(members) => {
            let deserialized: OutPointMemberMap = serde_json::from_value(members)?;
            deserialized.0
        }
        Err(_) => {
            debug!("creating members file at {}", members_file.path.display());
            members_file.create()?;

            HashMap::new()
        }
    };

    {
        let utxo_to_freeze: HashSet<OutPoint> = cached_processes
            .iter()
            .map(|(_, process)| process.get_last_unspent_outpoint().unwrap())
            .collect();

        let mut freezed_utxos = lock_freezed_utxos()?;
        *freezed_utxos = utxo_to_freeze;
    }

    let our_sp_address = sp_wallet.get_sp_client().get_receiving_address();

    log::info!("Using wallet with address {}", our_sp_address,);

    log::info!(
        "Found {} outputs for a total balance of {}",
        sp_wallet.get_outputs().len(),
        sp_wallet.get_balance()
    );

    let last_scan = sp_wallet.get_last_scan();

    WALLET
        .set(Mutex::new(sp_wallet))
        .expect("Failed to initialize WALLET");

    CACHEDPROCESSES
        .set(Mutex::new(cached_processes))
        .expect("Failed to initialize CACHEDPROCESSES");

    MEMBERLIST
        .set(Mutex::new(members))
        .expect("Failed to initialize MEMBERLIST");

    let storage = DiskStorage {
        wallet_file,
        processes_file,
        members_file,
    };

    STORAGE.set(Mutex::new(storage)).unwrap();

    let (sink, scan_rx, state_rx) = NativeUpdateSink::new();
    init_update_sink(Arc::new(sink));

    // Spawn the update handlers
    tokio::spawn(handle_scan_updates(scan_rx));
    tokio::spawn(handle_state_updates(state_rx));

    if last_scan < current_tip {
        log::info!("Scanning for our outputs");
        scan_blocks(current_tip - last_scan, &config.blindbit_url).await?;
    }

    // Subscribe to Bitcoin Core
    let zmq_url = config.zmq_url.clone();
    let blindbit_url = config.blindbit_url.clone();
    tokio::spawn(async move {
        handle_zmq(zmq_url, blindbit_url).await;
    });

    // Create the event loop and TCP listener we'll accept connections on.
    let try_socket = TcpListener::bind(config.ws_url).await;
    let listener = try_socket.expect("Failed to bind");

    tokio::spawn(MessageCache::clean_up());

    // Let's spawn the handling of each connection in a separate task.
    while let Ok((stream, addr)) = listener.accept().await {
        tokio::spawn(handle_connection(stream, addr, our_sp_address));
    }

    Ok(())
}