// Copyright (C) 2024 Riften Labs AS
//
// This software is licensed under the GNU Affero General Public License (AGPL), version 3.0 or later.
// A copy of the license can be found in the LICENSE file or at https://www.gnu.org/licenses/agpl-3.0.html
use std::time::{SystemTime, UNIX_EPOCH};

use anyhow::Result;
use bitcoin_hashes::hex::{FromHex, ToHex};
use bitcoincash::{BlockHash, TokenID, Txid};
use rusqlite::{params, Connection};

pub fn create_table(conn: &Connection) {
    let tbl = "CREATE TABLE tx (
            txid TEXT PRIMARY KEY,
            blockhash TEXT,
            mtp_timestamp BIGINT,
            first_seen_timestamp BIGINT
        )";

    conn.execute(tbl, []).expect("failed to create tx table");
}

pub fn insert_block_tx(
    conn: &rusqlite::Connection,
    txid: &Txid,
    blockhash: &BlockHash,
    mtp: i64,
) -> Result<()> {
    let sql = "INSERT INTO tx (txid, blockhash, mtp_timestamp)
               VALUES (?1, ?2, ?3)
               ON CONFLICT(txid) DO UPDATE SET
               blockhash = excluded.blockhash,
               mtp_timestamp = excluded.mtp_timestamp";
    conn.execute(sql, params![&txid.to_hex(), &blockhash.to_hex(), &mtp])?;
    Ok(())
}

pub fn insert_mempool_tx(conn: &rusqlite::Connection, txid: &Txid) -> Result<()> {
    let sql = "INSERT INTO tx (txid, first_seen_timestamp)
               VALUES (?1, ?2)
               ON CONFLICT(txid) DO UPDATE SET
               first_seen_timestamp = excluded.first_seen_timestamp";

    let current_timestamp = SystemTime::now()
        .duration_since(UNIX_EPOCH)
        .unwrap()
        .as_secs() as i64;

    conn.execute(sql, params![&txid.to_hex(), current_timestamp])?;
    Ok(())
}

pub fn latest(
    conn: &rusqlite::Connection,
    limit: usize,
    offset: usize,
    token_id: Option<TokenID>,
) -> Result<Vec<(Txid, Option<BlockHash>, u64)>, rusqlite::Error> {
    let (sql, params) = match token_id {
        Some(tid) => (
            "SELECT DISTINCT tx.txid, tx.blockhash, tx.mtp_timestamp, tx.first_seen_timestamp
            FROM tx
            JOIN utxo_funding ON tx.txid = utxo_funding.txid
            WHERE utxo_funding.token_id = ?
            ORDER BY COALESCE(tx.first_seen_timestamp, tx.mtp_timestamp) DESC
            LIMIT ? OFFSET ?",
            params![tid.to_hex(), limit, offset],
        ),
        None => (
            "SELECT tx.txid, tx.blockhash, tx.mtp_timestamp, tx.first_seen_timestamp
            FROM tx
            ORDER BY COALESCE(tx.first_seen_timestamp, tx.mtp_timestamp) DESC
            LIMIT ? OFFSET ?",
            params![limit, offset],
        ),
    };

    let mut stmt = conn.prepare(sql)?;
    let tx_iter = stmt.query_map(params, |row| {
        let txid_hex: String = row.get(0)?;
        let blockhash_hex: Option<String> = row.get(1)?;
        let mtp_timestamp: Option<u64> = row.get(2).ok(); // Handle potential NULL
        let first_seen_timestamp: Option<u64> = row.get(3).ok(); // Handle potential NULL

        // Use first_seen_timestamp if available, otherwise mtp_timestamp, or return an error if both are NULL
        let timestamp = first_seen_timestamp.or(mtp_timestamp).ok_or_else(|| {
            rusqlite::Error::InvalidColumnType(
                2,
                "timestamp".to_string(),
                rusqlite::types::Type::Null,
            )
        })?;

        Ok((
            Txid::from_hex(&txid_hex).expect("Invalid Txid hex"),
            blockhash_hex.map(|hex| BlockHash::from_hex(&hex).expect("Invalid BlockHash hex")),
            timestamp,
        ))
    })?;

    let mut txs = Vec::with_capacity(limit);
    for tx in tx_iter {
        txs.push(tx?);
    }

    Ok(txs)
}