// Copyright (C) 2024-2026 Whiterun LLC
//
// 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 bitcoincash::TokenID;
use rocket::{get, State};
use serde_json::json;
use serde_json::Value;

use crate::db::DB;
use crate::rpc::err::{bad_request, db_error, ApiErrorCode, CachedApiResult};
use crate::rpc::response::{cached_ok, CACHE_NONE};

/// Get the latest Cauldron transactions, optionally filtered by token.
///
/// Status: Stable
///
/// - limit: Maximum number of results (default: 100, max: 10000)
/// - offset: Pagination offset (default: 0)
/// - token: The 32 byte token ID to filter by (optional)
///
/// Note: `blockhash` is `null` for unconfirmed transactions.
/// `timestamp_guess` is an estimate derived from block time.
///
/// **Response Example:**
/// ```json
/// [
///   {
///     "txid": "94a933a0fa55093a0965eb867f1b9cac2bb07488ced4825bc31f86c9371f76aa",
///     "blockhash": "000000000000000002b4e6c0a1f4b3d2e5c7f891a2b3c4d5e6f7a8b9c0d1e2f3",
///     "timestamp_guess": 1709468902
///   }
/// ]
/// ```
#[get("/tx/latest?<limit>&<offset>&<token>")]
pub async fn tx_latest(
    limit: Option<usize>,
    offset: Option<usize>,
    token: Option<&str>,
    conn: &State<DB>,
) -> CachedApiResult<Value> {
    let limit = limit.unwrap_or(100).min(10000);
    let offset = offset.unwrap_or(0);

    let token = match token {
        None => None,
        Some(tokenhex) => match tokenhex.parse::<TokenID>() {
            Ok(token) => Some(token),
            Err(_) => {
                return Err(bad_request(
                    ApiErrorCode::InvalidTokenId,
                    "Invalid token ID",
                ))
            }
        },
    };

    let txs = crate::db::cauldron::tx::latest(&conn.cauldron_r, limit, offset, token)
        .await
        .map_err(db_error)?;

    let txs_json: Vec<Value> = txs
        .into_iter()
        .map(|tx| {
            json!({
                "txid": tx.0.to_string(),
                "blockhash": tx.1.map(|blockhex| blockhex.to_string()),
                "timestamp_guess": tx.2
            })
        })
        .collect();

    Ok(cached_ok(json!(txs_json), CACHE_NONE))
}