use crate::blocks::token::CreateTokenTransaction;
use crate::common::binary_conversions::binary_to_string;
use crate::fs;
use crate::records::balance_sheet::pathing::{balance_asset_segments, balance_root_path};
use crate::records::balance_sheet::tokens_to_lower::strip_spaces_and_lowercase;
use crate::rpc::commands::transaction_by_txid::request_transaction_by_txid;
use crate::rpc::responses::RpcResponse;
use crate::sled::{Db, Tree};
use crate::wallets::structures::Wallet;
use crate::PathBuf;
use crate::{decode, encode};

fn parse_token_supply(value: &[u8]) -> Option<u64> {
    // Token supply may be stored either as raw bytes or as a decimal string.
    if value.len() == 8 {
        let mut buffer = [0u8; 8];
        buffer.copy_from_slice(value);
        return Some(u64::from_le_bytes(buffer));
    }

    let value_str = binary_to_string(value.to_vec());
    value_str.trim().parse::<u64>().ok()
}

fn count_wallets_holding(normalized_token: &str) -> u64 {
    // Spread is computed by scanning address balance files for non-zero
    // holdings of the requested token.
    let mut count = 0_u64;
    let root = balance_root_path();

    let addresses = match fs::read_dir(&root) {
        Ok(entries) => entries,
        Err(_) => return 0,
    };

    for entry in addresses.flatten() {
        let entry_path = entry.path();
        if !entry_path.is_dir() {
            continue;
        }

        // Balance files are sharded under hashed asset path segments, so
        // reconstruct the expected token balance path for each address.
        let mut balance_path: PathBuf = entry_path.clone();
        for segment in balance_asset_segments(normalized_token) {
            balance_path.push(segment);
        }
        balance_path.push("wallet.bal");

        let bytes = match fs::read(&balance_path) {
            Ok(bytes) => bytes,
            Err(_) => continue,
        };

        if bytes.len() < 8 {
            continue;
        }

        let mut buffer = [0u8; 8];
        buffer.copy_from_slice(&bytes[..8]);
        if u64::from_le_bytes(buffer) > 0 {
            count += 1;
        }
    }

    count
}

async fn find_origin_hash(
    db: &Db,
    origins_tree: &Tree,
    matched_ticker: &str,
    normalized_query: &str,
) -> Option<String> {
    // Prefer the dedicated token-origins tree, but fall back to scanning
    // saved txids if the origin mapping is missing.
    if let Ok(Some(bytes)) = origins_tree.get(matched_ticker.as_bytes()) {
        return Some(binary_to_string(bytes.to_vec()));
    }

    let txid_tree = db.open_tree("txid").ok()?;
    for entry in txid_tree.iter() {
        let (txid_bytes, _) = match entry {
            Ok(pair) => pair,
            Err(_) => continue,
        };

        let RpcResponse::Binary(tx_bytes) =
            request_transaction_by_txid(db, txid_bytes.to_vec()).await;

        // The fallback only cares about create-token transactions because
        // those define the origin hash for a token.
        if tx_bytes.is_empty() || tx_bytes[0] != 3 {
            continue;
        }

        let contract = match CreateTokenTransaction::from_bytes(tx_bytes[0], &tx_bytes[1..]).await {
            Ok(tx) => tx,
            Err(_) => continue,
        };

        if strip_spaces_and_lowercase(&contract.unsigned_create_token.ticker) == normalized_query {
            return Some(encode(&txid_bytes));
        }
    }

    None
}

fn find_matching_ticker(
    tokens_tree: &Tree,
    origins_tree: &Tree,
    normalized_query: &str,
) -> Option<String> {
    // Prefer live token rows, but fall back to the origin registry so
    // fully burned tokens can still be looked up historically.
    for entry in tokens_tree.iter() {
        let (key, _) = match entry {
            Ok(pair) => pair,
            Err(_) => continue,
        };

        let stored_ticker = binary_to_string(key.to_vec());
        if strip_spaces_and_lowercase(&stored_ticker) == normalized_query {
            return Some(stored_ticker);
        }
    }

    for entry in origins_tree.iter() {
        let (key, _) = match entry {
            Ok(pair) => pair,
            Err(_) => continue,
        };

        let stored_ticker = binary_to_string(key.to_vec());
        if strip_spaces_and_lowercase(&stored_ticker) == normalized_query {
            return Some(stored_ticker);
        }
    }

    None
}

async fn collect_token_history(
    db: &Db,
    ticker: &str,
    origin_hash_bytes: &[u8],
) -> (Vec<[u8; 32]>, Vec<[u8; 32]>) {
    // Token lookup expands saved token history into separate issue and
    // burn txid lists so the current supply can be audited from history.
    let history_tree = match db.open_tree("token_history") {
        Ok(tree) => tree,
        Err(_) => return (Vec::new(), Vec::new()),
    };

    let mut issued_hashes = Vec::new();
    let mut burned_hashes = Vec::new();
    let Some(history_bytes) = history_tree
        .get(ticker.as_bytes())
        .ok()
        .flatten()
        .map(|bytes| bytes.to_vec())
    else {
        return (issued_hashes, burned_hashes);
    };

    for chunk in history_bytes.chunks(32) {
        if chunk.len() != 32 || chunk == origin_hash_bytes {
            continue;
        }

        let RpcResponse::Binary(tx_bytes) = request_transaction_by_txid(db, chunk.to_vec()).await;

        if tx_bytes.is_empty() {
            continue;
        }

        let mut hash = [0u8; 32];
        hash.copy_from_slice(chunk);

        // Token history stores txids only; inspect each transaction type
        // to divide the history into issue and burn lists.
        match tx_bytes[0] {
            10 => burned_hashes.push(hash),
            11 => issued_hashes.push(hash),
            _ => {}
        }
    }

    (issued_hashes, burned_hashes)
}

pub async fn lookup_token_details(db: &Db, token_name: String) -> RpcResponse {
    // Build the token-details response from token supply, origin txid,
    // creator wallet, holder spread, and related issuance and burn txids.
    let normalized_query = strip_spaces_and_lowercase(&token_name);
    if normalized_query.is_empty() {
        return RpcResponse::Binary(b"error: Token name required".to_vec());
    }

    let tokens_tree = db.open_tree("tokens").unwrap();
    let origins_tree = db.open_tree("token_origins").unwrap();
    let limits_tree = db.open_tree("token_limits").unwrap();

    let matched_ticker = match find_matching_ticker(&tokens_tree, &origins_tree, &normalized_query)
    {
        Some(ticker) => ticker,
        None => return RpcResponse::Binary(b"error: Token not found".to_vec()),
    };

    // Current supply comes from the live token registry, but fully
    // burned tokens still resolve historically through the origin tree.
    let token_count = tokens_tree
        .get(matched_ticker.as_bytes())
        .ok()
        .flatten()
        .and_then(|value| parse_token_supply(value.as_ref()));

    let origin_hash =
        match find_origin_hash(db, &origins_tree, &matched_ticker, &normalized_query).await {
            Some(hash) => hash,
            None => return RpcResponse::Binary(b"error: Token origin not found".to_vec()),
        };

    let RpcResponse::Binary(tx_bytes) =
        request_transaction_by_txid(db, decode(&origin_hash).unwrap_or_default()).await;

    if tx_bytes.is_empty() {
        return RpcResponse::Binary(b"error: Token contract transaction not found".to_vec());
    }

    let txtype = tx_bytes[0];
    let body = &tx_bytes[1..];
    let contract = match CreateTokenTransaction::from_bytes(txtype, body).await {
        Ok(tx) => tx,
        Err(_) => {
            return RpcResponse::Binary(b"error: Failed to parse token contract".to_vec());
        }
    };

    let spread = count_wallets_holding(&normalized_query);
    let token_count = token_count.unwrap_or(0);
    let contract_hash_bytes = match decode(&origin_hash) {
        Ok(bytes) if bytes.len() == 32 => bytes,
        _ => return RpcResponse::Binary(b"error: Failed to decode token origin".to_vec()),
    };

    let creator_bytes =
        match Wallet::short_address_to_bytes(&contract.unsigned_create_token.creator) {
            Some(bytes) => bytes,
            None => return RpcResponse::Binary(b"error: Failed to encode token creator".to_vec()),
        };
    let ticker_bytes = contract.unsigned_create_token.ticker.as_bytes().to_vec();
    if ticker_bytes.len() != 15 || creator_bytes.len() != Wallet::SHORT_ADDRESS_BYTES_LENGTH {
        return RpcResponse::Binary(b"error: Invalid token lookup response size".to_vec());
    }

    let hard_limit = limits_tree
        .get(matched_ticker.as_bytes())
        .ok()
        .flatten()
        .and_then(|bytes| bytes.first().copied())
        .unwrap_or(contract.unsigned_create_token.hard_limit);

    let (issued_hashes, burned_hashes) =
        collect_token_history(db, &matched_ticker, &contract_hash_bytes).await;

    // Response layout: ticker, origin hash, creator, live supply, holder
    // spread, hard-limit flag, issue-count/list, burn-count/list.
    let mut response = Vec::with_capacity(
        15 + 32
            + Wallet::SHORT_ADDRESS_BYTES_LENGTH
            + 8
            + 4
            + 1
            + 4
            + (issued_hashes.len() * 32)
            + 4
            + (burned_hashes.len() * 32),
    );
    response.extend_from_slice(&ticker_bytes);
    response.extend_from_slice(&contract_hash_bytes);
    response.extend_from_slice(&creator_bytes);
    response.extend_from_slice(&token_count.to_le_bytes());
    response.extend_from_slice(&(spread as u32).to_le_bytes());
    response.push(hard_limit);
    response.extend_from_slice(&(issued_hashes.len() as u32).to_le_bytes());
    for hash in issued_hashes {
        response.extend_from_slice(&hash);
    }
    response.extend_from_slice(&(burned_hashes.len() as u32).to_le_bytes());
    for hash in burned_hashes {
        response.extend_from_slice(&hash);
    }

    RpcResponse::Binary(response)
}

pub async fn token_catalog(db: &Db) -> RpcResponse {
    let tokens_tree = match db.open_tree("tokens") {
        Ok(tree) => tree,
        Err(err) => {
            return RpcResponse::Binary(
                format!("error: Failed to open tokens tree: {err}").into_bytes(),
            )
        }
    };
    let origins_tree = match db.open_tree("token_origins") {
        Ok(tree) => tree,
        Err(err) => {
            return RpcResponse::Binary(
                format!("error: Failed to open token origins tree: {err}").into_bytes(),
            )
        }
    };
    let limits_tree = match db.open_tree("token_limits") {
        Ok(tree) => tree,
        Err(err) => {
            return RpcResponse::Binary(
                format!("error: Failed to open token limits tree: {err}").into_bytes(),
            )
        }
    };

    let mut rows = Vec::new();

    for entry in origins_tree.iter() {
        let (ticker_key, origin_value) = match entry {
            Ok(pair) => pair,
            Err(_) => continue,
        };
        let ticker = binary_to_string(ticker_key.to_vec());
        let normalized_ticker = strip_spaces_and_lowercase(&ticker);
        if normalized_ticker.is_empty() {
            continue;
        }

        let origin_hash = binary_to_string(origin_value.to_vec());
        let origin_hash_bytes = match decode(&origin_hash) {
            Ok(bytes) if bytes.len() == 32 => bytes,
            _ => continue,
        };

        let RpcResponse::Binary(tx_bytes) =
            request_transaction_by_txid(db, origin_hash_bytes.clone()).await;
        if tx_bytes.is_empty() || tx_bytes[0] != 3 {
            continue;
        }

        let contract = match CreateTokenTransaction::from_bytes(tx_bytes[0], &tx_bytes[1..]).await {
            Ok(tx) => tx,
            Err(_) => continue,
        };

        let creator_bytes =
            match Wallet::short_address_to_bytes(&contract.unsigned_create_token.creator) {
                Some(bytes) => bytes,
                None => continue,
            };

        let current_supply = tokens_tree
            .get(ticker_key.as_ref())
            .ok()
            .flatten()
            .and_then(|value| parse_token_supply(value.as_ref()))
            .unwrap_or(0);
        let hard_limit = limits_tree
            .get(ticker_key.as_ref())
            .ok()
            .flatten()
            .and_then(|bytes| bytes.first().copied())
            .unwrap_or(contract.unsigned_create_token.hard_limit);

        let (_, burned_hashes) = collect_token_history(db, &ticker, &origin_hash_bytes).await;
        let mut total_burned = 0_u64;
        for hash in burned_hashes {
            let RpcResponse::Binary(burn_bytes) =
                request_transaction_by_txid(db, hash.to_vec()).await;
            if burn_bytes.is_empty() || burn_bytes[0] != 10 {
                continue;
            }
            let Ok(burn) =
                crate::blocks::burn::BurnTransaction::from_bytes(burn_bytes[0], &burn_bytes[1..])
                    .await
            else {
                continue;
            };
            if burn.unsigned_burn.nft_series == 0
                && strip_spaces_and_lowercase(&burn.unsigned_burn.coin) == normalized_ticker
            {
                total_burned = total_burned.saturating_add(burn.unsigned_burn.value);
            }
        }

        let mut padded_ticker = ticker.as_bytes().to_vec();
        if padded_ticker.len() < 15 {
            padded_ticker.resize(15, b' ');
        }
        if padded_ticker.len() != 15
            || creator_bytes.len() != Wallet::SHORT_ADDRESS_BYTES_LENGTH
            || origin_hash_bytes.len() != 32
        {
            continue;
        }

        rows.push((
            padded_ticker,
            origin_hash_bytes,
            creator_bytes,
            contract.unsigned_create_token.time,
            contract.unsigned_create_token.number,
            current_supply,
            total_burned,
            count_wallets_holding(&normalized_ticker) as u32,
            hard_limit,
        ));
    }

    rows.sort_by(|left, right| {
        binary_to_string(left.0.clone())
            .to_ascii_lowercase()
            .cmp(&binary_to_string(right.0.clone()).to_ascii_lowercase())
    });

    let mut response = Vec::with_capacity(4 + rows.len() * 102);
    response.extend_from_slice(&(rows.len() as u32).to_le_bytes());
    for (
        ticker,
        origin_hash,
        creator,
        created_timestamp,
        initial_supply,
        current_supply,
        total_burned,
        holder_count,
        hard_limit,
    ) in rows
    {
        response.extend_from_slice(&ticker);
        response.extend_from_slice(&origin_hash);
        response.extend_from_slice(&creator);
        response.extend_from_slice(&created_timestamp.to_le_bytes());
        response.extend_from_slice(&initial_supply.to_le_bytes());
        response.extend_from_slice(&current_supply.to_le_bytes());
        response.extend_from_slice(&total_burned.to_le_bytes());
        response.extend_from_slice(&holder_count.to_le_bytes());
        response.push(hard_limit);
    }

    RpcResponse::Binary(response)
}