// 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::{Context, Result};
use rayon::iter::{IntoParallelIterator, ParallelIterator};
use rocket::{get, http::Status, response::status::Custom, serde::json::Json, State};
use rusqlite::{params, Connection};
use serde_json::{json, Value};

use crate::{db::DBPool, timeutil::time_now};

/// Fetch TVL for all tokens
pub fn get_all_token_tvl(
    connection: &Connection,
    max_timestamp: usize,
) -> Result<Vec<(String, u64, u64)>> {
    let mut statement = connection.prepare(
        "SELECT
        uf.token_id,
        SUM(uf.token_amount) AS total_unspent_token_amount,
        SUM(uf.sats) AS total_unspent_sats
    FROM
        utxo_funding uf
    LEFT JOIN
        utxo_spending us ON uf.new_utxo_hash = us.spent_utxo_hash
    JOIN
        tx ON uf.txid = tx.txid
    WHERE
        us.spent_utxo_hash IS NULL AND
        (tx.mtp_timestamp <= ? OR tx.first_seen_timestamp <= ?)
    GROUP BY
        uf.token_id
    ",
    )?;

    let tvl: Vec<(String, u64, u64)> = statement
        .query_and_then([max_timestamp, max_timestamp], |row| {
            let token_id: String = row.get(0)?;
            let token_amount: u64 = row.get(1)?;
            let sats: u64 = row.get(2)?;
            Ok((token_id, token_amount, sats))
        })
        .unwrap()
        .map(|row: Result<(String, u64, u64)>| row.unwrap())
        .collect();

    Ok(tvl)
}

/// Get TVL for a single token
pub fn get_token_tvl(
    connection: &Connection,
    max_timestamp: usize,
    token_id: &str,
) -> Result<(u64, u64)> {
    let mut statement = connection.prepare(
        "SELECT
            uf.token_amount,
            uf.sats
        FROM
            utxo_funding uf
        LEFT JOIN
            utxo_spending us ON uf.new_utxo_hash = us.spent_utxo_hash
        JOIN
            tx ON uf.txid = tx.txid
        WHERE
            us.spent_utxo_hash IS NULL AND
            (tx.mtp_timestamp <= ? OR tx.first_seen_timestamp <= ?) AND
            uf.token_id = ?
        ",
    )?;

    // Execute the query with the specified parameters
    let mut query = statement.query(params![max_timestamp, max_timestamp, token_id])?;

    // Initialize accumulators
    let mut sum_tokens: u64 = 0;
    let mut sum_sats: u64 = 0;

    // Iterate over the query result
    while let Some(row) = query.next()? {
        let tokens: u64 = row.get(0)?;
        let sats: u64 = row.get(1)?;
        sum_tokens = sum_tokens.checked_add(tokens).context("token overflow")?;
        sum_sats = sum_sats.checked_add(sats).context("sats overflow")?;
    }

    Ok((sum_sats, sum_tokens))
}

// Deprecated; use valuelocked with optional parameters
#[get("/tvl/<time>")]
pub fn deprecated_tvl(
    time: usize,
    conn: &State<DBPool>,
) -> Result<Json<Vec<Value>>, Custom<String>> {
    let db = conn
        .get()
        .map_err(|e| Custom(Status::InternalServerError, format!("Error: {}", e)))?;

    let tvl: Vec<(String, u64, u64)> = get_all_token_tvl(&db, time)
        .map_err(|e| Custom(Status::InternalServerError, format!("Error: {}", e)))?;

    let result: Vec<Value> = tvl
        .into_par_iter()
        .map(|(token, token_amount, sats)| {
            json!({
                "token_id": token,
                "token_amount": token_amount,
                "satoshis": sats
            })
        })
        .collect();

    Ok(Json(result))
}

#[get("/valuelocked?<time>")]
pub fn valuelocked_all(
    time: Option<usize>,
    conn: &State<DBPool>,
) -> Result<Json<Vec<Value>>, Custom<String>> {
    let db = conn.get().map_err(|_| {
        Custom(
            Status::InternalServerError,
            "Failed to get DB connection".into(),
        )
    })?;

    let time_filter = time.unwrap_or_else(|| time_now() as usize);

    let tvl: Vec<(String, u64, u64)> = get_all_token_tvl(&db, time_filter)
        .map_err(|e| Custom(Status::InternalServerError, format!("Error: {}", e)))?;

    let result: Vec<Value> = tvl
        .into_par_iter()
        .map(|(token, token_amount, sats)| {
            json!({
                "token_id": token,
                "token_amount": token_amount,
                "satoshis": sats
            })
        })
        .collect();

    Ok(Json(result))
}

#[get("/valuelocked/<token>?<time>")]
pub fn valuelocked_token(
    token: &str,
    time: Option<usize>,
    conn: &State<DBPool>,
) -> Result<Json<Value>, Custom<String>> {
    let db = conn.get().map_err(|_| {
        Custom(
            Status::InternalServerError,
            "Failed to get DB connection".into(),
        )
    })?;

    let time_filter = time.unwrap_or_else(|| time_now() as usize);

    let (sats, token_amount) = get_token_tvl(&db, time_filter, token)
        .map_err(|e| Custom(Status::InternalServerError, format!("Error: {}", e)))?;

    Ok(Json(json!({
        "token_amount": token_amount,
        "satoshis": sats
    })))
}