// 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 crate::db::oracle::{get_closest, get_range, get_range_with_step};
use crate::db::DB;
use crate::rpc::err::{bad_request, db_error, not_found, ApiErrorCode, CachedApiResult};
use crate::rpc::response::{cached_ok, CACHE_AGGREGATE};
use crate::timeutil::time_now;
use bitcoin_hashes::hex::FromHex;
use bitcoincash::TokenID;
use rocket::{get, State};
use serde_json::{json, Value};

/// Get the closest oracle price for a given token and timestamp.
///
/// Status: Stable
///
/// - token_id: The 32 byte token ID of the oracle contract. Known IDs:
///   - **BCH/USD v2 (current, live)**: `be0d0d8324e8cda41d34b85bd203ce2482256eb337a0ad0fea82c2ddd7306c88`
///   - BCH/USD v1 (legacy, no longer updated): `d0d46f5cbd82188acede0d3e49c75700c19cb8331a30101f0bb6a260066ac972`
/// - timestamp: Unix timestamp (optional, defaults to now)
///
/// When `token_id` is omitted, the closest entry across **all** indexed
/// Delphi contracts is returned. After the v2 deploy this naturally resolves
/// to the most recent live oracle (v2), since v1 stopped advancing; callers
/// who want a specific contract should pass `token_id=…` explicitly.
///
/// Reserve UTXOs and `price=0` updates (the operator's "feed disabled"
/// signal) are filtered at index time, so any non-null entry returned here
/// is a live price.
///
/// Returns `null` if no oracle data is found.
///
/// **Important:** `oracle_price` is returned in **cents** (not dollars). Divide by 100
/// to get the price in USD:
/// ```
/// price_usd = oracle_price / 100
/// ```
///
/// **Response Example:**
/// ```json
/// {
///   "oracle_timestamp": 1777889180,
///   "oracle_price": 43972,
///   "oracle_sequence": 1646804,
///   "token_id": "be0d0d8324e8cda41d34b85bd203ce2482256eb337a0ad0fea82c2ddd7306c88",
///   "txid": "...",
///   "blockhash": "..."
/// }
/// ```
/// In this example, `oracle_price` of 43972 cents = $439.72 USD.
#[get("/delphi/closest?<token_id>&<timestamp>")]
pub async fn oracle_get_closest(
    token_id: Option<String>,
    timestamp: Option<i64>,
    db: &State<DB>,
) -> CachedApiResult<serde_json::Value> {
    let current_timestamp = timestamp.unwrap_or_else(time_now);
    let token_id = token_id
        .map(|t| {
            TokenID::from_hex(&t).map_err(|e| {
                bad_request(
                    ApiErrorCode::InvalidTokenId,
                    &format!("Invalid token ID: {e}"),
                )
            })
        })
        .transpose()?;
    let entry = get_closest(&db.oracle_r, &token_id, current_timestamp)
        .await
        .map_err(db_error)?;
    Ok(cached_ok(
        entry.map_or(serde_json::Value::Null, |e| {
            serde_json::to_value(e).unwrap()
        }),
        CACHE_AGGREGATE,
    ))
}

/// Status: Deprecated. Use `/delphi/<token>/history` instead.
#[get("/delphi/range?<token_id>&<start>&<end>")]
pub async fn oracle_get_range(
    token_id: Option<String>,
    start: Option<i64>,
    end: Option<i64>,
    db: &State<DB>,
) -> CachedApiResult<Vec<serde_json::Value>> {
    let end_timestamp = end.unwrap_or_else(time_now);
    let start_timestamp = start.unwrap_or_else(|| end_timestamp - 86400);
    let token_id = token_id
        .map(|t| {
            TokenID::from_hex(&t).map_err(|e| {
                bad_request(
                    ApiErrorCode::InvalidTokenId,
                    &format!("Invalid token ID: {e}"),
                )
            })
        })
        .transpose()?;
    let entries = get_range(&db.oracle_r, &token_id, start_timestamp, end_timestamp)
        .await
        .map_err(db_error)?;
    Ok(cached_ok(
        entries
            .into_iter()
            .map(|e| serde_json::to_value(e).unwrap())
            .collect(),
        CACHE_AGGREGATE,
    ))
}

/// Get historical oracle prices for a given token.
///
/// - token: The 32 byte token ID of the oracle contract. Known IDs:
///   - **BCH/USD v2 (current, live)**: `be0d0d8324e8cda41d34b85bd203ce2482256eb337a0ad0fea82c2ddd7306c88`
///   - BCH/USD v1 (legacy, no longer updated): `d0d46f5cbd82188acede0d3e49c75700c19cb8331a30101f0bb6a260066ac972`
/// - start: Unix timestamp for start of period
/// - end: Unix timestamp for end of period (optional, defaults to now)
/// - stepsize: Seconds per interval (optional)
///
/// Reserve UTXOs and `price=0` updates (the operator's "feed disabled"
/// signal) are filtered at index time, so every entry returned here is a
/// live price.
///
/// **Important:** `oracle_price` values are in **cents**. Divide by 100 to convert to USD.
///
/// **Response Example:**
/// ```json
/// [
///   { "time": 1777886180, "price": 43900, "txid": "...", "blockhash": "...", "sequence": 1646803 },
///   { "time": 1777889180, "price": 43972, "txid": "...", "blockhash": "...", "sequence": 1646804 }
/// ]
/// ```
/// In this example, `price` values of 43972 cents = $439.72 USD.
#[get("/delphi/<token>/history?<start>&<end>&<stepsize>")]
pub async fn oracle_get_history(
    token: &str,
    start: Option<i64>,
    end: Option<i64>,
    stepsize: Option<i64>,
    db: &State<DB>,
) -> CachedApiResult<Value> {
    let current_timestamp = time_now();

    let token_id = token.parse::<TokenID>().map_err(|e| {
        bad_request(
            ApiErrorCode::InvalidTokenId,
            &format!("Invalid token ID: {e}"),
        )
    })?;

    let start_ts = start.unwrap_or(current_timestamp - 30 * 24 * 3600);
    let end_ts = end.unwrap_or(current_timestamp);

    let entries = if let Some(step) = stepsize {
        get_range_with_step(&db.oracle_r, &Some(token_id), start_ts, end_ts, step)
            .await
            .map_err(|e| {
                bad_request(
                    ApiErrorCode::InvalidParameters,
                    &format!("Query error: {e}"),
                )
            })?
    } else {
        get_range(&db.oracle_r, &Some(token_id), start_ts, end_ts)
            .await
            .map_err(|e| {
                bad_request(
                    ApiErrorCode::InvalidParameters,
                    &format!("Query error: {e}"),
                )
            })?
    };

    let json_entries: Vec<Value> = entries
        .into_iter()
        .map(|entry| {
            json!({
                "time": entry.oracle_timestamp,
                "price": entry.oracle_price,
                "txid": entry.txid,
                "blockhash": entry.blockhash,
                "sequence": entry.oracle_sequence,
            })
        })
        .collect();

    Ok(cached_ok(
        serde_json::Value::Array(json_entries),
        CACHE_AGGREGATE,
    ))
}

/// Delphi oracle updates roughly every 5–15 minutes. An entry more than 2 hours
/// older than the requested timestamp means there is genuinely no price for that
/// period (e.g. the Apr 23–May 4 2026 gap between v1 and v2).
const MAX_ORACLE_STALENESS_SECS: i64 = 7200;

/// Get the closest BCH/USD price for a given timestamp.
/// Returns 404 if no oracle price is available within 2 hours of the timestamp.
#[get("/cash/closest?<timestamp>")]
pub async fn oracle_cash_closest(
    timestamp: Option<i64>,
    db: &State<DB>,
) -> CachedApiResult<serde_json::Value> {
    let ts = timestamp.unwrap_or_else(time_now);
    let entry = get_closest(&db.oracle_r, &None, ts)
        .await
        .map_err(db_error)?;

    match entry {
        Some(e) if ts - e.oracle_timestamp <= MAX_ORACLE_STALENESS_SECS => {
            Ok(cached_ok(serde_json::to_value(e).unwrap(), CACHE_AGGREGATE))
        }
        _ => Err(not_found(
            ApiErrorCode::PriceNotFound,
            &format!("No oracle price available for timestamp {ts}"),
        )),
    }
}

/// Get historical BCH/USD prices for a time range.
/// Backed by Delphi v2 (and v1 for historical timestamps).
#[get("/cash/history?<start>&<end>&<stepsize>")]
pub async fn oracle_cash_history(
    start: Option<i64>,
    end: Option<i64>,
    stepsize: Option<i64>,
    db: &State<DB>,
) -> CachedApiResult<Value> {
    let current_timestamp = time_now();
    let start_ts = start.unwrap_or(current_timestamp - 30 * 24 * 3600);
    let end_ts = end.unwrap_or(current_timestamp);

    let entries = if let Some(step) = stepsize {
        get_range_with_step(&db.oracle_r, &None, start_ts, end_ts, step)
            .await
            .map_err(|e| {
                bad_request(
                    ApiErrorCode::InvalidParameters,
                    &format!("Query error: {e}"),
                )
            })?
    } else {
        get_range(&db.oracle_r, &None, start_ts, end_ts)
            .await
            .map_err(|e| {
                bad_request(
                    ApiErrorCode::InvalidParameters,
                    &format!("Query error: {e}"),
                )
            })?
    };

    Ok(cached_ok(
        serde_json::to_value(entries).unwrap(),
        CACHE_AGGREGATE,
    ))
}