use crate::common::skein::skein_256_hash_data;
use crate::records::memory::mempool::DB;
use crate::to_string;
use crate::wallets::structures::Wallet;
use crate::Cursor;
use crate::Serialize;
use crate::{decode, encode};
use crate::{AsyncReadExt, AsyncWriteExt};

#[derive(Debug, Serialize, Clone)] // 57 bytes
pub struct UnsignedVanityAddressTransaction {
    pub txtype: u8,             // 1 byte             transaction type, should be 12
    pub timestamp: u32,         // 4 bytes            transaction timestamp
    pub address: String, // 22 bytes           real short address receiving the vanity mapping
    pub vanity_address: String, // 22 bytes           vanity short address being registered
    pub txfee: u64,      // 8 bytes            fee paid for vanity registration
}

#[derive(Debug, Serialize, Clone)] // 723 bytes
pub struct VanityAddressTransaction {
    pub unsigned_vanity_address: UnsignedVanityAddressTransaction, // 57 bytes
    pub signature: String,                                         // 666 bytes
}

impl VanityAddressTransaction {
    pub const BYTE_LENGTH: usize = 1
        + 4
        + Wallet::SHORT_ADDRESS_BYTES_LENGTH
        + Wallet::SHORT_ADDRESS_BYTES_LENGTH
        + 8
        + Wallet::SIGNATURE_LENGTH;
}

impl UnsignedVanityAddressTransaction {
    // Create the unsigned vanity-address registration payload.
    pub async fn new(
        txtype: u8,
        timestamp: u32,
        address: &str,
        vanity_address: &str,
        txfee: u64,
    ) -> Self {
        Self {
            txtype,
            timestamp,
            address: address.to_string(),
            vanity_address: vanity_address.to_string(),
            txfee,
        }
    }

    pub async fn hash(&self) -> String {
        // Hash the unsigned payload for verification and mempool indexing.
        let serialized = to_string(self).unwrap();
        skein_256_hash_data(&serialized)
    }

    pub async fn hash_and_sign(
        &self,
        private_key: &str,
    ) -> Result<String, Box<dyn std::error::Error>> {
        // Sign the unsigned vanity transaction with the registering wallet.
        let serialized = to_string(self)?;
        let hash = skein_256_hash_data(&serialized);
        let signature = Wallet::sign_transaction(&hash, private_key).await;
        Ok(signature)
    }
}

impl VanityAddressTransaction {
    pub async fn new(
        unsigned_vanity_address: UnsignedVanityAddressTransaction,
        private_key: &str,
    ) -> Result<Self, Box<dyn std::error::Error>> {
        // Create a signed vanity-address transaction.
        let signature = unsigned_vanity_address.hash_and_sign(private_key).await?;
        Ok(Self {
            unsigned_vanity_address,
            signature,
        })
    }

    pub async fn load(
        unsigned_vanity_address: UnsignedVanityAddressTransaction,
        signature: &str,
    ) -> Self {
        // Rebuild a vanity transaction already read from storage.
        Self {
            unsigned_vanity_address,
            signature: signature.to_string(),
        }
    }

    pub async fn to_bytes(&self) -> tokio::io::Result<Vec<u8>> {
        // Serialize into the fixed vanity transaction byte layout.
        let mut buffer = Vec::with_capacity(Self::BYTE_LENGTH);
        let mut cursor = Cursor::new(&mut buffer);

        cursor
            .write_all(&self.unsigned_vanity_address.txtype.to_le_bytes())
            .await?;
        cursor
            .write_all(&self.unsigned_vanity_address.timestamp.to_le_bytes())
            .await?;

        let address_bytes =
            Wallet::short_address_to_bytes(&self.unsigned_vanity_address.address)
                .ok_or_else(|| tokio::io::Error::other("Invalid sender short address"))?;
        // Vanity addresses use the same 22-byte width as short addresses
        // but are encoded through the vanity-specific byte conversion.
        let vanity_bytes =
            Wallet::vanity_address_to_bytes(&self.unsigned_vanity_address.vanity_address)
                .ok_or_else(|| tokio::io::Error::other("Invalid vanity short address"))?;

        cursor.write_all(&address_bytes).await?;
        cursor.write_all(&vanity_bytes).await?;
        cursor
            .write_all(&self.unsigned_vanity_address.txfee.to_le_bytes())
            .await?;
        let signature_bytes = decode(&self.signature).map_err(|err| {
            tokio::io::Error::other(format!("Invalid vanity signature hex: {err}"))
        })?;
        cursor.write_all(&signature_bytes).await?;

        Ok(buffer)
    }

    pub async fn from_bytes(txtype: u8, bytes: &[u8]) -> tokio::io::Result<Self> {
        // The block parser already consumed the transaction type byte.
        if bytes.len() != Self::BYTE_LENGTH - 1 {
            return Err(tokio::io::Error::other("Invalid Byte Count"));
        }

        let mut cursor = Cursor::new(bytes);

        // Decode timestamp, real short address, vanity address, fee, and signature.
        let timestamp = cursor.read_u32_le().await?;

        let mut address_bytes = vec![0; Wallet::SHORT_ADDRESS_BYTES_LENGTH];
        cursor.read_exact(&mut address_bytes).await?;
        let address = Wallet::bytes_to_short_address(&address_bytes)
            .ok_or_else(|| tokio::io::Error::other("Invalid sender short address bytes"))?;

        let mut vanity_bytes = vec![0; Wallet::SHORT_ADDRESS_BYTES_LENGTH];
        cursor.read_exact(&mut vanity_bytes).await?;
        let vanity_address = Wallet::bytes_to_vanity_address(&vanity_bytes)
            .ok_or_else(|| tokio::io::Error::other("Invalid vanity short address bytes"))?;

        let txfee = cursor.read_u64_le().await?;

        let mut signature_bytes = vec![0; Wallet::SIGNATURE_LENGTH];
        cursor.read_exact(&mut signature_bytes).await?;
        let signature = encode(&signature_bytes);

        let unsigned_vanity_address = UnsignedVanityAddressTransaction {
            txtype,
            timestamp,
            address,
            vanity_address,
            txfee,
        };

        Ok(Self {
            unsigned_vanity_address,
            signature,
        })
    }

    pub async fn add_to_memory(&self) -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
        // Store the original bytes so the mempool can later rebuild the
        // exact transaction submitted by the wallet.
        let original_data = self.to_bytes().await?;

        // PostgreSQL uses signed integer types for these persisted fields.
        let time = self.unsigned_vanity_address.timestamp as i32;
        let fee = i64::try_from(self.unsigned_vanity_address.txfee)
            .map_err(|_| std::io::Error::other("Vanity fee exceeds i64 mempool limit"))?;
        let address = &self.unsigned_vanity_address.address;
        let vanity_address = &self.unsigned_vanity_address.vanity_address;
        let hash = &self.unsigned_vanity_address.hash().await;
        let signature = &self.signature;

        // Vanity transactions are written to the vanity mempool table
        // until the transaction is mined or removed.
        let client = DB.get().ok_or_else(|| {
            Box::new(std::io::Error::other("DB not initialized"))
                as Box<dyn std::error::Error + Send + Sync>
        })?;

        client
            .execute(
                r#"
                INSERT INTO vanity_address (
                    time,
                    fee,
                    address,
                    vanity_address,
                    hash,
                    signature,
                    original
                ) VALUES ($1, $2, $3, $4, $5, $6, $7)
                "#,
                &[
                    &time,
                    &fee,
                    address,
                    vanity_address,
                    hash,
                    signature,
                    &original_data,
                ],
            )
            .await?;

        Ok(())
    }
}