use blockchain::common::binary_conversions::binary_to_string;
use blockchain::common::cli_prompts::prompt_hidden_nonempty;
use blockchain::common::network_startup::get_connections;
use blockchain::encode;
use blockchain::env;
use blockchain::json;
use blockchain::records::memory::response_channels::generate_uid;
use blockchain::standalone_tools::connections::handshake;
use blockchain::wallets::structures::Wallet;
use blockchain::{Map, Value};

const NFT_NAME_BYTES: usize = 15;
const SERIES_BYTES: usize = 4;
const GENESIS_HASH_BYTES: usize = 32;
const CREATOR_BYTES: usize = Wallet::SHORT_ADDRESS_BYTES_LENGTH;
const IPFS_BYTES: usize = 100;
const HOLDER_BYTES: usize = Wallet::SHORT_ADDRESS_BYTES_LENGTH;
const HISTORY_COUNT_BYTES: usize = 4;
const HISTORY_ENTRY_SIZE: usize =
    32 + 4 + 1 + 1 + (2 * Wallet::SHORT_ADDRESS_BYTES_LENGTH) + 15 + 4 + 8;
const NFT_LOOKUP_FIXED_BYTES: usize = NFT_NAME_BYTES
    + SERIES_BYTES
    + GENESIS_HASH_BYTES
    + CREATOR_BYTES
    + IPFS_BYTES
    + HOLDER_BYTES
    + HISTORY_COUNT_BYTES;

fn action_name(action: u8) -> &'static str {
    // History action bytes are stored compactly on the wire and expanded for display.
    match action {
        1 => "create_nft",
        2 => "transfer",
        3 => "swap",
        4 => "loan_locked",
        5 => "loan_payment",
        6 => "collateral_claimed",
        7 => "loan_issued",
        _ => "unknown",
    }
}

fn decode_wallet(bytes: &[u8]) -> String {
    // Empty wallet fields are encoded as all zeroes; otherwise decode a short address.
    if bytes.iter().all(|b| *b == 0) {
        String::new()
    } else {
        Wallet::bytes_to_short_address(bytes).unwrap_or_default()
    }
}

fn decode_history_entry(entry: &[u8]) -> Option<Value> {
    // Each history row has a fixed binary size so bad lengths mean an invalid response.
    if entry.len() != HISTORY_ENTRY_SIZE {
        return None;
    }

    // Decode the history fields in the same order the RPC command writes them.
    let txid = encode(&entry[0..32]);
    let block = u32::from_le_bytes(entry[32..36].try_into().ok()?);
    let txtype = entry[36];
    let action = entry[37];
    let from = decode_wallet(&entry[38..60]);
    let to = decode_wallet(&entry[60..82]);
    let received_asset = binary_to_string(entry[82..97].to_vec()).trim().to_string();
    let received_series = u32::from_le_bytes(entry[97..101].try_into().ok()?);
    let received_value_raw = u64::from_le_bytes(entry[101..109].try_into().ok()?);
    let received_value = received_value_raw as f64 / 100_000_000.0;

    // Omit empty optional fields so the CLI output stays readable.
    let mut obj = Map::new();
    obj.insert("txid".to_string(), json!(txid));
    obj.insert("block".to_string(), json!(block));
    obj.insert("txtype".to_string(), json!(txtype));
    obj.insert("action".to_string(), json!(action_name(action)));

    if !from.is_empty() {
        obj.insert("from".to_string(), json!(from));
    }
    if !to.is_empty() {
        obj.insert("to".to_string(), json!(to));
    }
    if !received_asset.is_empty() {
        obj.insert("received_asset".to_string(), json!(received_asset));
        if received_series > 0 {
            obj.insert("received_series".to_string(), json!(received_series));
        }
        obj.insert("received_value".to_string(), json!(received_value));
    }

    Some(Value::Object(obj))
}

fn decode_nft_lookup(response: &[u8]) -> Option<String> {
    // The fixed NFT fields must exist before any history entries can be decoded.
    if response.len() < NFT_LOOKUP_FIXED_BYTES {
        return None;
    }

    // Decode the fixed-width NFT metadata fields in wire order.
    let mut cursor = 0usize;
    let nft_name = binary_to_string(response[cursor..cursor + NFT_NAME_BYTES].to_vec())
        .trim()
        .to_string();
    cursor += NFT_NAME_BYTES;

    let series = u32::from_le_bytes(response[cursor..cursor + SERIES_BYTES].try_into().ok()?);
    cursor += SERIES_BYTES;

    let genesis = encode(&response[cursor..cursor + GENESIS_HASH_BYTES]);
    cursor += GENESIS_HASH_BYTES;

    let creator = Wallet::bytes_to_short_address(&response[cursor..cursor + CREATOR_BYTES])?;
    cursor += CREATOR_BYTES;

    let ipfs_cid = binary_to_string(response[cursor..cursor + IPFS_BYTES].to_vec())
        .trim()
        .to_string();
    cursor += IPFS_BYTES;

    let current_holder = decode_wallet(&response[cursor..cursor + HOLDER_BYTES]);
    cursor += HOLDER_BYTES;

    let history_count = u32::from_le_bytes(
        response[cursor..cursor + HISTORY_COUNT_BYTES]
            .try_into()
            .ok()?,
    );
    cursor += HISTORY_COUNT_BYTES;

    // Any remaining bytes are fixed-size history entries.
    let mut history = Vec::new();
    let mut offset = cursor;
    while offset + HISTORY_ENTRY_SIZE <= response.len() {
        if let Some(entry) = decode_history_entry(&response[offset..offset + HISTORY_ENTRY_SIZE]) {
            history.push(entry);
        }
        offset += HISTORY_ENTRY_SIZE;
    }

    // Convert the binary record into user-facing JSON.
    let mut output = Map::new();
    output.insert("nft_name".to_string(), json!(nft_name));
    output.insert("series".to_string(), json!(series));
    if series == 0 {
        output.insert("ipfs".to_string(), json!(format!("ipfs://{ipfs_cid}")));
    } else {
        output.insert(
            "ipfs".to_string(),
            json!(format!("ipfs://{ipfs_cid}/{series}.json")),
        );
    }
    if series > 0 {
        output.insert(
            "asset_name".to_string(),
            json!(format!("{nft_name}_{series}")),
        );
    }
    output.insert("genesis".to_string(), json!(genesis));
    output.insert("creator".to_string(), json!(creator));
    output.insert("current_holder".to_string(), json!(current_holder));
    output.insert("history_count".to_string(), json!(history_count));
    output.insert("history".to_string(), Value::Array(history));

    serde_json::to_string_pretty(&Value::Object(output)).ok()
}

#[tokio::main]
async fn main() {
    // Command 36 asks a peer for NFT metadata by name and series/item number.
    let hashmap_key = generate_uid();
    let rpc_command = 36;

    // Item number 0 means a 1/1 NFT; nonzero values identify a series item.
    let args: Vec<String> = env::args().collect();
    if args.len() != 3 {
        println!("Usage: ./lookup_nft <nft_name> <item_number>");
        println!("Use item_number 0 for a 1/1 NFT, or the specific item number for a series NFT.");
        return;
    }

    let nft_name = args[1].clone();
    let item_number = args[2].clone();
    let encryption_key = prompt_hidden_nonempty(
        "What is your wallet decryption key? ",
        "Wallet key cannot be empty. Please try again.",
    )
    .await;
    // sending_request expects command 36 lookup input as "name|series".
    let payload = format!("{nft_name}|{item_number}");

    // Try each configured peer until one returns a parsable NFT record or text error.
    let connections = get_connections().await;
    let mut connected = false;

    for conn in connections {
        if connected {
            break;
        }

        let socket_address = conn.parse().expect("Failed to parse the socket address");
        let result = handshake::connect_and_handshake(
            socket_address,
            payload.clone(),
            rpc_command,
            handshake::HandshakeWallet::WalletKey(encryption_key.clone()),
            hashmap_key,
        )
        .await;

        match result {
            Ok(response) => {
                // Successful NFT lookups are binary records; errors are returned as text.
                if let Some(output) = decode_nft_lookup(&response) {
                    println!("{output}");
                    connected = true;
                } else {
                    let response_text = String::from_utf8_lossy(&response);
                    let trimmed = response_text.trim();
                    if !trimmed.is_empty() {
                        println!("{trimmed}");
                        connected = true;
                    }
                }
            }
            Err(_) => connected = false,
        }
    }

    if !connected {
        eprintln!("failed to connect");
    }
}