use super::RpcHandler;
use anyhow::{Context, Result};
use serde::{Deserialize, Serialize};
use zeroize::Zeroize;

#[derive(Debug, Serialize)]
struct BitcoinInfo {
    block_height: u64,
    sync_progress: f64,
    chain: String,
    difficulty: f64,
    mempool_size: u64,
    mempool_tx_count: u64,
    verification_progress: f64,
}

#[derive(Debug, Deserialize)]
struct BitcoinRpcResponse<T> {
    result: Option<T>,
    error: Option<serde_json::Value>,
}

#[derive(Debug, Deserialize)]
struct BlockchainInfo {
    chain: Option<String>,
    blocks: Option<u64>,
    difficulty: Option<f64>,
    #[serde(rename = "verificationprogress")]
    verification_progress: Option<f64>,
}

#[derive(Debug, Deserialize)]
struct MempoolInfo {
    size: Option<u64>,
    bytes: Option<u64>,
}

impl RpcHandler {
    pub(super) async fn handle_bitcoin_getinfo(&self) -> Result<serde_json::Value> {
        let client = reqwest::Client::builder()
            .timeout(std::time::Duration::from_secs(10))
            .build()
            .context("Failed to create HTTP client")?;

        let blockchain_info = self
            .bitcoin_rpc_call::<BlockchainInfo>(&client, "getblockchaininfo", &[])
            .await
            .context("Failed to query getblockchaininfo")?;

        let mempool_info = self
            .bitcoin_rpc_call::<MempoolInfo>(&client, "getmempoolinfo", &[])
            .await
            .unwrap_or(MempoolInfo {
                size: Some(0),
                bytes: Some(0),
            });

        let info = BitcoinInfo {
            block_height: blockchain_info.blocks.unwrap_or(0),
            sync_progress: blockchain_info.verification_progress.unwrap_or(0.0),
            chain: blockchain_info.chain.unwrap_or_else(|| "unknown".into()),
            difficulty: blockchain_info.difficulty.unwrap_or(0.0),
            mempool_size: mempool_info.bytes.unwrap_or(0),
            mempool_tx_count: mempool_info.size.unwrap_or(0),
            verification_progress: blockchain_info.verification_progress.unwrap_or(0.0),
        };

        Ok(serde_json::to_value(info)?)
    }

    async fn bitcoin_rpc_call<T: serde::de::DeserializeOwned>(
        &self,
        client: &reqwest::Client,
        method: &str,
        params: &[serde_json::Value],
    ) -> Result<T> {
        let (rpc_user, rpc_pass) = crate::bitcoin_rpc::bitcoin_rpc_credentials().await;
        let body = serde_json::json!({
            "jsonrpc": "1.0",
            "id": "archy",
            "method": method,
            "params": params,
        });

        let resp = client
            .post(crate::constants::BITCOIN_RPC_URL)
            .basic_auth(&rpc_user, Some(&rpc_pass))
            .json(&body)
            .send()
            .await
            .context("Bitcoin RPC connection failed")?;

        let rpc_resp: BitcoinRpcResponse<T> = resp
            .json()
            .await
            .context("Failed to parse Bitcoin RPC response")?;

        if let Some(err) = rpc_resp.error {
            anyhow::bail!("Bitcoin RPC error: {}", err);
        }

        rpc_resp
            .result
            .ok_or_else(|| anyhow::anyhow!("Bitcoin RPC returned null result"))
    }

    /// Initialize a Bitcoin Core descriptor wallet with keys derived from the master seed.
    /// Creates a blank wallet and imports BIP-84 (native segwit) descriptors.
    /// Requires: password re-verification, encrypted seed on disk.
    pub(super) async fn handle_bitcoin_init_wallet_from_seed(
        &self,
        params: Option<serde_json::Value>,
    ) -> Result<serde_json::Value> {
        let params = params.ok_or_else(|| anyhow::anyhow!("Missing params"))?;
        let password = params
            .get("password")
            .and_then(|v| v.as_str())
            .ok_or_else(|| anyhow::anyhow!("Missing 'password' for seed access"))?;
        let wallet_name = params
            .get("wallet_name")
            .and_then(|v| v.as_str())
            .unwrap_or("archipelago");

        // Verify user password.
        self.auth_manager
            .verify_password(password)
            .await
            .context("Password verification failed")?;

        // Load encrypted seed.
        let mnemonic = crate::seed::load_seed_encrypted(&self.config.data_dir, password)
            .await
            .context("Failed to load encrypted seed")?;
        let seed = crate::seed::MasterSeed::from_mnemonic(&mnemonic);

        // Derive BIP-84 account xprv.
        let xprv = crate::seed::derive_bitcoin_xprv(&seed)?;
        let mut xprv_str = xprv.to_string();

        let client = reqwest::Client::builder()
            .timeout(std::time::Duration::from_secs(30))
            .build()
            .context("Failed to create HTTP client")?;

        // Step 1: Create a blank descriptor wallet.
        let create_result = self
            .bitcoin_rpc_call::<serde_json::Value>(
                &client,
                "createwallet",
                &[
                    serde_json::json!(wallet_name), // wallet_name
                    serde_json::json!(false),       // disable_private_keys
                    serde_json::json!(true),        // blank
                    serde_json::json!(""),          // passphrase
                    serde_json::json!(false),       // avoid_reuse
                    serde_json::json!(true),        // descriptors
                ],
            )
            .await;

        match create_result {
            Ok(_) => tracing::info!("Created blank descriptor wallet '{}'", wallet_name),
            Err(e) => {
                let msg = e.to_string();
                if msg.contains("already exists") {
                    tracing::info!(
                        "Wallet '{}' already exists, importing descriptors",
                        wallet_name
                    );
                } else {
                    xprv_str.zeroize();
                    return Err(e.context("Failed to create wallet"));
                }
            }
        }

        // Step 2: Import BIP-84 descriptors (external + internal/change).
        // Format: wpkh(xprv/0/*) for receive, wpkh(xprv/1/*) for change.
        let external_desc = format!("wpkh({}/0/*)", xprv_str);
        let internal_desc = format!("wpkh({}/1/*)", xprv_str);

        // Get checksums from Bitcoin Core.
        let ext_info: serde_json::Value = self
            .bitcoin_rpc_call(
                &client,
                "getdescriptorinfo",
                &[serde_json::json!(external_desc)],
            )
            .await
            .context("getdescriptorinfo failed for external descriptor")?;

        let int_info: serde_json::Value = self
            .bitcoin_rpc_call(
                &client,
                "getdescriptorinfo",
                &[serde_json::json!(internal_desc)],
            )
            .await
            .context("getdescriptorinfo failed for internal descriptor")?;

        let ext_desc_with_checksum = ext_info
            .get("descriptor")
            .and_then(|v| v.as_str())
            .ok_or_else(|| anyhow::anyhow!("No descriptor in getdescriptorinfo response"))?;
        let int_desc_with_checksum = int_info
            .get("descriptor")
            .and_then(|v| v.as_str())
            .ok_or_else(|| anyhow::anyhow!("No descriptor in getdescriptorinfo response"))?;

        let import_params = serde_json::json!([
            {
                "desc": ext_desc_with_checksum,
                "timestamp": "now",
                "active": true,
                "internal": false,
                "range": [0, 1000],
            },
            {
                "desc": int_desc_with_checksum,
                "timestamp": "now",
                "active": true,
                "internal": true,
                "range": [0, 1000],
            }
        ]);

        let _import_result: serde_json::Value = self
            .bitcoin_rpc_call(&client, "importdescriptors", &[import_params])
            .await
            .context("importdescriptors failed")?;

        // Zeroize the xprv string from memory.
        xprv_str.zeroize();

        tracing::info!(
            "Bitcoin Core wallet '{}' initialized from master seed (BIP-84)",
            wallet_name
        );

        Ok(serde_json::json!({
            "initialized": true,
            "wallet_name": wallet_name,
        }))
    }
}