// 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::{
    cashaddr::utiladdr::p2pkh_hex_to_addr,
    db::{
        cauldron::{
            pool::{db_pool_get_details, db_pool_history, db_pool_id_from_utxo},
            poolvisitor::{
                db_visit_pool_entries, OptionalFields, OptionalPoolFields, PoolFilters, PoolVisitor,
            },
        },
        DB,
    },
    def::PoolID,
    rpc::err::{bad_request, db_error, not_found, ApiErrorCode, CachedApiResult},
    rpc::response::{cached_ok, CACHE_AGGREGATE, CACHE_NONE},
    timeutil::time_now,
};
use anyhow::Result;
use bitcoin_hashes::hex::{FromHex, ToHex};
use bitcoincash::Txid;
use riftenlabs_defi::chainutil::compute_outpoint_hash;
use rocket::{get, State};
use serde_json::{json, Value};

#[derive(serde::Serialize)]
struct ActivePool {
    owner_pkh: String,
    owner_p2pkh_addr: String,
    token_id: String,
    sats: u64,
    tokens: u64,
    txid: String,
    tx_pos: u32,
    pool_id: String,
}

#[derive(Default)]
struct ActivePoolList {
    active: Vec<ActivePool>,
}

impl PoolVisitor for ActivePoolList {
    fn optional_fields_wanted(&self) -> u64 {
        OptionalPoolFields::Owner as u64
            | OptionalPoolFields::Txid as u64
            | OptionalPoolFields::TxPos as u64
            | OptionalPoolFields::TokenId as u64
            | OptionalPoolFields::PoolId as u64
    }

    fn visit(&mut self, sats: u64, tokens: u64, optional_fields: OptionalFields) -> Result<bool> {
        let owner_pkh = optional_fields.owner.unwrap().to_lowercase();
        let owner_p2pkh_addr = p2pkh_hex_to_addr(&owner_pkh)?;

        self.active.push(ActivePool {
            owner_pkh,
            owner_p2pkh_addr,
            token_id: optional_fields.token_id.unwrap().to_lowercase(),
            sats,
            tokens,
            txid: optional_fields.txid.unwrap().to_lowercase(),
            tx_pos: optional_fields.tx_pos.unwrap(),
            pool_id: optional_fields.pool_id.unwrap().to_lowercase(),
        });

        Ok(true)
    }
}

/// Get list of active pools for given token and/or user.
/// Either user or token ID must be provided.
///
/// - user: 20 byte hash of a users pkh
/// - token: byte token ID.
///
/// Status: Stable
///
/// - token: Token ID or symbol
/// - pkh: Public key hash
///
/// **Response Example:**
/// ```json
/// {
///   "active": [
///     {
///       "owner_p2pkh_addr": "bitcoincash:zqmvqqsd6w08e4nvy8er0hzn6wzxvxj40u7tlk8wl3",
///       "owner_pkh": "36c0020dd39e7cd66c21f237dc53d384661a557f",
///       "sats": 776661580,
///       "token_id": "b79bfc8246b5fc4707e7c7dedcb6619ef1ab91f494a790c20b0f4c422ed95b92",
///       "tokens": 16,
///       "tx_pos": 0,
///       "txid": "94a933a0fa55093a0965eb867f1b9cac2bb07488ced4825bc31f86c9371f76aa"
///     }
///   ]
/// }
/// ```
#[get("/pool/active?<token>&<pkh>")]
pub async fn list_active_pools(
    token: Option<&str>,
    pkh: Option<&str>,
    conn: &State<DB>,
) -> CachedApiResult<Value> {
    if token.is_none() && pkh.is_none() {
        return Err(bad_request(
            ApiErrorCode::MissingParameters,
            "Provide token or pkh",
        ));
    }

    let mut active_pool_list = ActivePoolList::default();
    db_visit_pool_entries(
        &conn.cauldron_r,
        &mut active_pool_list,
        PoolFilters {
            token_id: token.map(|s| s.to_string()),
            owner: pkh.map(|s| s.to_string()),
            timestamp_lt: None,
            timestamp_lte: None,
            timestamp_gt: None,
            timestamp_gte: None,
        },
    )
    .await
    .map_err(db_error)?;

    Ok(cached_ok(
        json!({
            "active": active_pool_list.active,
        }),
        CACHE_NONE,
    ))
}

/// Get historical state changes for a specific pool.
///
/// Returns the price history (token/BCH ratio) over time. Each entry represents
/// a state change event.
///
/// - pool_id: The pool ID (can be obtained via `/pool/id_from_utxo`)
/// - start: Unix timestamp for period start (default: 30 days ago)
///
/// **Response Example:**
/// ```json
/// {
///   "history": [
///     {
///       "sats": 1000000,
///       "tokens": 500,
///       "timestamp": 1709468902,
///       "txid": "..."
///     }
///   ],
///   "token_id": "b79bfc8246b5fc4707e7c7dedcb6619ef1ab91f494a790c20b0f4c422ed95b92",
///   "owner_pkh": "36c0020dd39e7cd66c21f237dc53d384661a557f"
/// }
/// ```
#[get("/pool/history/<pool_id>?<start>")]
pub async fn pool_history(
    pool_id: &str,
    start: Option<u64>,
    conn: &State<DB>,
) -> CachedApiResult<Value> {
    let start = start.unwrap_or(time_now() as u64 - (30 * 3600 * 24) /* 30 days ago */);

    let pool_id = PoolID::from_hex(pool_id).map_err(|e| {
        bad_request(
            ApiErrorCode::InvalidPoolId,
            &format!("Invalid pool ID: {e}"),
        )
    })?;

    let (token_id, owner_pkh) = db_pool_get_details(&conn.cauldron_r, &pool_id)
        .await
        .map_err(|e| {
            let err_msg = e.to_string();
            if err_msg.contains("not found") || err_msg.contains("no rows") {
                not_found(ApiErrorCode::PoolNotFound, &format!("Pool not found: {e}"))
            } else {
                db_error(e)
            }
        })?;

    let history = db_pool_history(&conn.cauldron_r, &pool_id, start)
        .await
        .map_err(db_error)?;

    Ok(cached_ok(
        json!({
            "history": history,
            "token_id": token_id,
            "owner_pkh": owner_pkh,
        }),
        CACHE_NONE,
    ))
}

/// Get pool ID from a UTXO specified by transaction ID and output position.
///
/// - txid: Transaction ID (hex string)
/// - n: Output position (vout) in the transaction
///
/// **Response Example:**
/// ```json
/// {
///   "pool_id": "a1b2c3d4e5f6..."
/// }
/// ```
#[get("/pool/id_from_utxo?<txid>&<n>")]
pub async fn pool_id_from_utxo(txid: &str, n: u32, conn: &State<DB>) -> CachedApiResult<Value> {
    let txid = Txid::from_hex(txid)
        .map_err(|e| bad_request(ApiErrorCode::InvalidTxid, &format!("Invalid txid: {e}")))?;

    let utxo_hash = compute_outpoint_hash(&txid, n);

    let pool_id = db_pool_id_from_utxo(&conn.cauldron_r, &utxo_hash)
        .await
        .map_err(db_error)?;

    match pool_id {
        Some(pool_id) => Ok(cached_ok(
            json!({
                "pool_id": pool_id
            }),
            CACHE_AGGREGATE,
        )),
        None => Err(not_found(
            ApiErrorCode::PoolNotFound,
            &format!(
                "No pool found for UTXO: txid={}, input_pos={}",
                txid.to_hex(),
                n
            ),
        )),
    }
}