// 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 anyhow::Result;
use log::warn;
use rusqlite::Connection;

use crate::db::cauldron::pool::get_pool_period_snapshot;
use crate::db::oracle::get_closest;
use crate::rpc::apy::apyaggregator::APYAggregator;
use crate::rpc::apy::poolperiod::PoolPeriod;

use rust_decimal::prelude::*;
use rust_decimal::Decimal;

pub const SATS_PER_BCH: i64 = 100_000_000;
pub const ORACLE_SCALE: i64 = 1_000_000; // match the delphi scale

pub fn usd_per_bch_at_or_before(conn: &Connection, ts: i64) -> Decimal {
    match get_closest(conn, &None, ts) {
        Ok(Some(e)) => {
            Decimal::from_i64(e.oracle_price).unwrap_or(Decimal::ZERO)
                / Decimal::from_i64(ORACLE_SCALE).unwrap() // USD/BCH
        }
        _ => Decimal::ZERO,
    }
}

#[inline]
pub fn pct_change_bp_dec(current: Decimal, past: Decimal) -> i64 {
    if past.is_zero() {
        0
    } else {
        ((current - past) / past * Decimal::from_i32(10_000).unwrap())
            .round()
            .to_i64()
            .unwrap_or(0)
    }
}

#[inline]
pub fn compute_score(tvl_sats: u64, volume: u64) -> i64 {
    if tvl_sats == 0 || volume == 0 {
        return 0;
    }
    let s = (volume as f64) * (tvl_sats as f64).sqrt(); // same as BigNumber sqrt + pow(2) pattern
    if !s.is_finite() {
        return 0;
    }
    if s >= i64::MAX as f64 {
        i64::MAX
    } else {
        s.round() as i64
    } // ROUND_HALF_UP for positives
}

pub fn resolve_decimals(bcmr_conn: &Connection, crc20_conn: &Connection, token_id: &str) -> u32 {
    // On-chain BCMR (latest by height)
    if let Ok(Some(v)) = bcmr_conn.query_row(
        r#"
        SELECT decimals FROM (
          SELECT b.decimals, a.height,
                 ROW_NUMBER() OVER (PARTITION BY a.token_id ORDER BY a.height DESC) rn
          FROM auth_chain_entry a
          LEFT JOIN bcmr_data b ON a.utxo = b.utxo
          WHERE a.bcmr_data IS NOT NULL AND a.token_id = ?1
        ) s WHERE rn = 1
        "#,
        [token_id],
        |r| r.get::<_, Option<i64>>(0),
    ) {
        let dd = v.max(0) as u32;
        if dd > 0 {
            return dd; // only accept positive
        }
    }

    // Well-known BCMR
    if let Ok(Some(v)) = bcmr_conn.query_row(
        r#"SELECT decimals FROM bcmr_well_known WHERE token_id = ?1 ORDER BY source LIMIT 1"#,
        [token_id],
        |r| r.get::<_, Option<i64>>(0),
    ) {
        let dd = v.max(0) as u32;
        if dd > 0 {
            return dd;
        }
    }

    // CRC20 fallback
    if let Ok(Some(v)) = crc20_conn.query_row(
        r#"SELECT decimals FROM crc20 WHERE token_id = ?1 LIMIT 1"#,
        [token_id],
        |r| r.get::<_, Option<i64>>(0),
    ) {
        let dd = v.max(0) as u32;
        if dd > 0 {
            return dd;
        }
    }

    // Final fallback
    0
}

#[inline]
pub fn pow10_dec(decimals: u32) -> Decimal {
    // rust_decimal supports integer powers
    Decimal::from_i32(10).unwrap().powu(decimals as u64)
}

#[inline]
pub fn price_from_tvl(tvl_sats: u64, tvl_tokens: u64) -> Option<Decimal> {
    if tvl_tokens == 0 {
        return None;
    }
    let sats = Decimal::from_u64(tvl_sats)?;
    let tokens = Decimal::from_u64(tvl_tokens)?;
    sats.checked_div(tokens)
}

pub fn apy_30d_bp_for_token(conn: &Connection, token_id: &str, now: i64) -> Result<i64> {
    let start = now - 30 * 86_400;

    let pairs = get_pool_period_snapshot(conn, Some(token_id), None, start, now)?;
    let periods = pairs
        .into_iter()
        .filter(|(s, e)| {
            e.timestamp > s.timestamp
                && s.sats > 0
                && s.token_amount > 0
                && e.sats > 0
                && e.token_amount > 0
        })
        .map(|(s, e)| PoolPeriod::new(s, e))
        .collect::<Result<Vec<_>>>()?;

    if periods.is_empty() {
        return Ok(0);
    }

    let apy_dec = match APYAggregator::aggregate_apy(periods.into_iter(), Some(start as u64)) {
        Ok(v) => v, // v is a PERCENT value, e.g. 5.239 = 5.239%
        Err(e) => {
            warn!(
                "aggregate_apy failed for token {} over 30d: {}",
                token_id, e
            );
            Decimal::ZERO
        }
    };

    // Percent → basis points (100 bp = 1%)
    Ok((apy_dec * Decimal::from_i32(100).unwrap())
        .round()
        .to_i64()
        .unwrap_or(0))
}

pub fn resolve_display_labels(
    bcmr_conn: &Connection,
    crc20_conn: &Connection,
    token_id: &str,
) -> Result<(String, String)> {
    // On-chain BCMR (latest by height)
    let mut onchain = bcmr_conn.prepare(
        r#"
        SELECT name, symbol FROM (
          SELECT b.name, b.symbol, a.height,
                 ROW_NUMBER() OVER (PARTITION BY a.token_id ORDER BY a.height DESC) rn
          FROM auth_chain_entry a
          LEFT JOIN bcmr_data b ON a.utxo = b.utxo
          WHERE a.bcmr_data IS NOT NULL AND a.token_id = ?1
        ) s WHERE rn = 1
        "#,
    )?;
    if let Ok(row) = onchain.query_row([token_id], |r| {
        Ok((r.get::<_, String>(0)?, r.get::<_, String>(1)?))
    }) {
        let (name, sym) = row;
        let dn = if !name.is_empty() {
            name
        } else if !sym.is_empty() {
            sym.clone()
        } else {
            token_id.to_string()
        };
        return Ok((dn, sym));
    }

    // Well-known BCMR (pick a deterministic row)
    let mut wk = bcmr_conn.prepare(
        r#"SELECT name, symbol FROM bcmr_well_known WHERE token_id = ?1 ORDER BY source LIMIT 1"#,
    )?;
    if let Ok(row) = wk.query_row([token_id], |r| {
        Ok((r.get::<_, String>(0)?, r.get::<_, String>(1)?))
    }) {
        let (name, sym) = row;
        let dn = if !name.is_empty() {
            name
        } else if !sym.is_empty() {
            sym.clone()
        } else {
            token_id.to_string()
        };
        return Ok((dn, sym));
    }

    // CRC20 fallback
    let mut crc =
        crc20_conn.prepare(r#"SELECT name, symbol FROM crc20 WHERE token_id = ?1 LIMIT 1"#)?;
    if let Ok(row) = crc.query_row([token_id], |r| {
        Ok((r.get::<_, String>(0)?, r.get::<_, String>(1)?))
    }) {
        let (name, sym) = row;
        let dn = if !name.is_empty() {
            name
        } else if !sym.is_empty() {
            sym.clone()
        } else {
            token_id.to_string()
        };
        return Ok((dn, sym));
    }

    // Last resort
    Ok((token_id.to_string(), String::new()))
}