use std::{
    env, mem,
    path::{Path, PathBuf},
    sync::Arc,
    thread::sleep,
    time::Duration,
};

use bitcoin::consensus::encode;
use brk_error::{Error, Result};
use brk_types::{
    BlockHash, Height, MempoolEntryInfo, Sats, Transaction, TxIn, TxOut, TxStatus, TxWithHex, Txid,
    Vout,
};

pub mod backend;

pub use backend::{Auth, BlockHeaderInfo, BlockInfo, BlockchainInfo, TxOutInfo};

use backend::ClientInner;
use tracing::{debug, info};

///
/// Bitcoin Core RPC Client
///
/// Thread safe and free to clone
///
#[derive(Debug, Clone)]
pub struct Client(Arc<ClientInner>);

impl Client {
    pub fn new(url: &str, auth: Auth) -> Result<Self> {
        Self::new_with(url, auth, 1_000_000, Duration::from_secs(1))
    }

    pub fn new_with(
        url: &str,
        auth: Auth,
        max_retries: usize,
        retry_delay: Duration,
    ) -> Result<Self> {
        Ok(Self(Arc::new(ClientInner::new(
            url,
            auth,
            max_retries,
            retry_delay,
        )?)))
    }

    /// Returns a data structure containing various state info regarding
    /// blockchain processing.
    pub fn get_blockchain_info(&self) -> Result<BlockchainInfo> {
        self.0.get_blockchain_info()
    }

    pub fn get_block<'a, H>(&self, hash: &'a H) -> Result<bitcoin::Block>
    where
        &'a H: Into<&'a bitcoin::BlockHash>,
    {
        self.0.get_block(hash.into())
    }

    /// Returns the numbers of block in the longest chain.
    pub fn get_block_count(&self) -> Result<u64> {
        self.0.get_block_count()
    }

    /// Returns the numbers of block in the longest chain.
    pub fn get_last_height(&self) -> Result<Height> {
        self.0.get_block_count().map(Height::from)
    }

    /// Get block hash at a given height
    pub fn get_block_hash<H>(&self, height: H) -> Result<BlockHash>
    where
        H: Into<u64> + Copy,
    {
        self.0.get_block_hash(height.into()).map(BlockHash::from)
    }

    pub fn get_block_header<'a, H>(&self, hash: &'a H) -> Result<bitcoin::block::Header>
    where
        &'a H: Into<&'a bitcoin::BlockHash>,
    {
        self.0.get_block_header(hash.into())
    }

    pub fn get_block_info<'a, H>(&self, hash: &'a H) -> Result<BlockInfo>
    where
        &'a H: Into<&'a bitcoin::BlockHash>,
    {
        self.0.get_block_info(hash.into())
    }

    pub fn get_block_header_info<'a, H>(&self, hash: &'a H) -> Result<BlockHeaderInfo>
    where
        &'a H: Into<&'a bitcoin::BlockHash>,
    {
        self.0.get_block_header_info(hash.into())
    }

    pub fn get_transaction<'a, T, H>(
        &self,
        txid: &'a T,
        block_hash: Option<&'a H>,
    ) -> brk_error::Result<bitcoin::Transaction>
    where
        &'a T: Into<&'a bitcoin::Txid>,
        &'a H: Into<&'a bitcoin::BlockHash>,
    {
        let tx = self.get_raw_transaction(txid, block_hash)?;
        Ok(tx)
    }

    pub fn get_mempool_transaction(&self, txid: &Txid) -> Result<TxWithHex> {
        // Get hex first, then deserialize from it
        let hex = self.get_raw_transaction_hex(txid, None as Option<&BlockHash>)?;
        let mut tx = encode::deserialize_hex::<bitcoin::Transaction>(&hex)?;

        let input = mem::take(&mut tx.input)
            .into_iter()
            .map(|txin| -> Result<TxIn> {
                let txout_result = self.get_tx_out(
                    (&txin.previous_output.txid).into(),
                    txin.previous_output.vout.into(),
                    Some(true),
                )?;

                let is_coinbase = txout_result.as_ref().is_none_or(|r| r.coinbase);

                let txout = if let Some(txout_result) = txout_result {
                    Some(TxOut::from((
                        txout_result.script_pub_key,
                        txout_result.value,
                    )))
                } else {
                    None
                };

                let witness = txin
                    .witness
                    .iter()
                    .map(bitcoin::hex::DisplayHex::to_lower_hex_string)
                    .collect();

                Ok(TxIn {
                    is_coinbase,
                    prevout: txout,
                    txid: txin.previous_output.txid.into(),
                    vout: txin.previous_output.vout.into(),
                    script_sig: txin.script_sig,
                    script_sig_asm: (),
                    witness,
                    sequence: txin.sequence.into(),
                    inner_redeem_script_asm: (),
                    inner_witness_script_asm: (),
                })
            })
            .collect::<Result<Vec<_>>>()?;

        let mut tx = Transaction {
            index: None,
            txid: txid.clone(),
            version: tx.version.into(),
            total_sigop_cost: tx.total_sigop_cost(|_| None),
            weight: tx.weight().into(),
            lock_time: tx.lock_time.into(),
            total_size: tx.total_size(),
            fee: Sats::default(),
            input,
            output: tx.output.into_iter().map(TxOut::from).collect(),
            status: TxStatus::UNCONFIRMED,
        };

        tx.compute_fee();

        Ok(TxWithHex::new(tx, hex))
    }

    pub fn get_tx_out(
        &self,
        txid: &Txid,
        vout: Vout,
        include_mempool: Option<bool>,
    ) -> Result<Option<TxOutInfo>> {
        self.0.get_tx_out(txid.into(), vout.into(), include_mempool)
    }

    /// Get txids of all transactions in a memory pool
    pub fn get_raw_mempool(&self) -> Result<Vec<Txid>> {
        self.0
            .get_raw_mempool()
            .map(|v| unsafe { mem::transmute(v) })
    }

    /// Get all mempool entries with their fee data in a single RPC call
    pub fn get_raw_mempool_verbose(&self) -> Result<Vec<MempoolEntryInfo>> {
        let result = self.0.get_raw_mempool_verbose()?;
        Ok(result
            .into_iter()
            .map(
                |(txid, entry): (bitcoin::Txid, backend::RawMempoolEntry)| MempoolEntryInfo {
                    txid: txid.into(),
                    vsize: entry.vsize,
                    weight: entry.weight,
                    fee: Sats::from(entry.base_fee_sats),
                    ancestor_count: entry.ancestor_count,
                    ancestor_size: entry.ancestor_size,
                    ancestor_fee: Sats::from(entry.ancestor_fee_sats),
                    depends: entry.depends.into_iter().map(Txid::from).collect(),
                },
            )
            .collect())
    }

    pub fn get_raw_transaction<'a, T, H>(
        &self,
        txid: &'a T,
        block_hash: Option<&'a H>,
    ) -> brk_error::Result<bitcoin::Transaction>
    where
        &'a T: Into<&'a bitcoin::Txid>,
        &'a H: Into<&'a bitcoin::BlockHash>,
    {
        let hex = self.get_raw_transaction_hex(txid, block_hash)?;
        let tx = encode::deserialize_hex::<bitcoin::Transaction>(&hex)?;
        Ok(tx)
    }

    pub fn get_raw_transaction_hex<'a, T, H>(
        &self,
        txid: &'a T,
        block_hash: Option<&'a H>,
    ) -> Result<String>
    where
        &'a T: Into<&'a bitcoin::Txid>,
        &'a H: Into<&'a bitcoin::BlockHash>,
    {
        self.0
            .get_raw_transaction_hex(txid.into(), block_hash.map(|h| h.into()))
    }

    pub fn send_raw_transaction(&self, hex: &str) -> Result<Txid> {
        self.0.send_raw_transaction(hex).map(Txid::from)
    }

    /// Checks if a block is in the main chain (has positive confirmations)
    pub fn is_in_main_chain(&self, hash: &BlockHash) -> Result<bool> {
        let block_info = self.get_block_info(hash)?;
        Ok(block_info.confirmations > 0)
    }

    pub fn get_closest_valid_height(&self, hash: BlockHash) -> Result<(Height, BlockHash)> {
        debug!("Get closest valid height...");

        match self.get_block_header_info(&hash) {
            Ok(block_info) => {
                if self.is_in_main_chain(&hash)? {
                    return Ok((block_info.height.into(), hash));
                }

                let mut hash =
                    block_info
                        .previous_block_hash
                        .map(BlockHash::from)
                        .ok_or(Error::NotFound(
                            "Genesis block has no previous block".into(),
                        ))?;

                loop {
                    if self.is_in_main_chain(&hash)? {
                        let current_info = self.get_block_header_info(&hash)?;
                        return Ok((current_info.height.into(), hash));
                    }

                    let info = self.get_block_header_info(&hash)?;
                    hash = info
                        .previous_block_hash
                        .map(BlockHash::from)
                        .ok_or(Error::NotFound(
                            "Reached genesis without finding main chain".into(),
                        ))?;
                }
            }
            Err(_) => Err(Error::NotFound("Block hash not found in blockchain".into())),
        }
    }

    pub fn wait_for_synced_node(&self) -> Result<()> {
        let is_synced = || -> Result<bool> {
            let info = self.get_blockchain_info()?;
            Ok(info.headers == info.blocks)
        };

        if !is_synced()? {
            info!("Waiting for node to sync...");
            while !is_synced()? {
                sleep(Duration::from_secs(1))
            }
        }

        Ok(())
    }

    #[cfg(feature = "bitcoincore-rpc")]
    pub fn call<F, T>(&self, f: F) -> Result<T, bitcoincore_rpc::Error>
    where
        F: Fn(&bitcoincore_rpc::Client) -> Result<T, bitcoincore_rpc::Error>,
    {
        self.0.call_with_retry(f)
    }

    #[cfg(feature = "bitcoincore-rpc")]
    pub fn call_once<F, T>(&self, f: F) -> Result<T, bitcoincore_rpc::Error>
    where
        F: Fn(&bitcoincore_rpc::Client) -> Result<T, bitcoincore_rpc::Error>,
    {
        self.0.call_once(f)
    }

    pub fn default_url() -> &'static str {
        "http://localhost:8332"
    }

    pub fn default_bitcoin_path() -> PathBuf {
        if env::consts::OS == "macos" {
            Self::default_mac_bitcoin_path()
        } else {
            Self::default_linux_bitcoin_path()
        }
    }

    pub fn default_linux_bitcoin_path() -> PathBuf {
        Path::new(&env::var("HOME").unwrap()).join(".bitcoin")
    }

    pub fn default_mac_bitcoin_path() -> PathBuf {
        Path::new(&env::var("HOME").unwrap())
            .join("Library")
            .join("Application Support")
            .join("Bitcoin")
    }
}
