use crate::{
    config::{Config, ExplicitRelease},
    stop_process::stop_process,
    update_manifest::{SignedUpdateManifest, UpdateManifest},
};
use chrono::{Local, TimeZone};
use console::{style, Emoji};
use indicatif::{ProgressBar, ProgressStyle};
use solana_client::rpc_client::RpcClient;
use solana_config_program::{config_instruction, get_config_data, ConfigState};
use solana_sdk::{
    hash::{Hash, Hasher},
    message::Message,
    pubkey::Pubkey,
    signature::{read_keypair_file, Keypair, KeypairUtil, Signable},
    transaction::Transaction,
};
use std::{
    fs::{self, File},
    io::{self, BufReader, Read},
    path::{Path, PathBuf},
    sync::mpsc,
    time::{Duration, Instant, SystemTime},
};
use tempdir::TempDir;
use url::Url;

static TRUCK: Emoji = Emoji("🚚 ", "");
static LOOKING_GLASS: Emoji = Emoji("🔍 ", "");
static BULLET: Emoji = Emoji("• ", "* ");
static SPARKLE: Emoji = Emoji("✨ ", "");
static PACKAGE: Emoji = Emoji("📦 ", "");
static INFORMATION: Emoji = Emoji("ℹ️  ", "");

/// Creates a new process bar for processing that will take an unknown amount of time
fn new_spinner_progress_bar() -> ProgressBar {
    let progress_bar = ProgressBar::new(42);
    progress_bar
        .set_style(ProgressStyle::default_spinner().template("{spinner:.green} {wide_msg}"));
    progress_bar.enable_steady_tick(100);
    progress_bar
}

/// Pretty print a "name value"
fn println_name_value(name: &str, value: &str) {
    println!("{} {}", style(name).bold(), value);
}

/// Downloads the release archive at `url` to a temporary location.  If `expected_sha256` is
/// Some(_), produce an error if the release SHA256 doesn't match.
///
/// Returns a tuple consisting of:
/// * TempDir - drop this value to clean up the temporary location
/// * PathBuf - path to the downloaded release (within `TempDir`)
/// * String  - SHA256 of the release
///
fn download_to_temp_archive(
    url: &str,
    expected_sha256: Option<&Hash>,
) -> Result<(TempDir, PathBuf, Hash), Box<dyn std::error::Error>> {
    fn sha256_file_digest<P: AsRef<Path>>(path: P) -> Result<Hash, Box<dyn std::error::Error>> {
        let input = File::open(path)?;
        let mut reader = BufReader::new(input);
        let mut hasher = Hasher::default();

        let mut buffer = [0; 1024];
        loop {
            let count = reader.read(&mut buffer)?;
            if count == 0 {
                break;
            }
            hasher.hash(&buffer[..count]);
        }
        Ok(hasher.result())
    }

    let url = Url::parse(url).map_err(|err| format!("Unable to parse {}: {}", url, err))?;

    let temp_dir = TempDir::new(clap::crate_name!())?;
    let temp_file = temp_dir.path().join("release.tar.bz2");

    let client = reqwest::Client::new();

    let progress_bar = new_spinner_progress_bar();
    progress_bar.set_message(&format!("{}Downloading...", TRUCK));

    let response = client.get(url.as_str()).send()?;
    let download_size = {
        response
            .headers()
            .get(reqwest::header::CONTENT_LENGTH)
            .and_then(|content_length| content_length.to_str().ok())
            .and_then(|content_length| content_length.parse().ok())
            .unwrap_or(0)
    };

    progress_bar.set_length(download_size);
    progress_bar.set_style(
        ProgressStyle::default_bar()
            .template(&format!(
                "{}{}{}",
                "{spinner:.green} ",
                TRUCK,
                "Downloading [{bar:40.cyan/blue}] {bytes}/{total_bytes} ({eta})"
            ))
            .progress_chars("=> "),
    );

    struct DownloadProgress<R> {
        progress_bar: ProgressBar,
        response: R,
    }

    impl<R: Read> Read for DownloadProgress<R> {
        fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
            self.response.read(buf).map(|n| {
                self.progress_bar.inc(n as u64);
                n
            })
        }
    }

    let mut source = DownloadProgress {
        progress_bar,
        response,
    };

    let mut file = File::create(&temp_file)?;
    std::io::copy(&mut source, &mut file)?;

    let temp_file_sha256 = sha256_file_digest(&temp_file)
        .map_err(|err| format!("Unable to hash {:?}: {}", temp_file, err))?;

    if expected_sha256.is_some() && expected_sha256 != Some(&temp_file_sha256) {
        return Err(io::Error::new(io::ErrorKind::Other, "Incorrect hash").into());
    }

    source.progress_bar.finish_and_clear();
    Ok((temp_dir, temp_file, temp_file_sha256))
}

/// Extracts the release archive into the specified directory
fn extract_release_archive(
    archive: &Path,
    extract_dir: &Path,
) -> Result<(), Box<dyn std::error::Error>> {
    use bzip2::bufread::BzDecoder;
    use tar::Archive;

    let progress_bar = new_spinner_progress_bar();
    progress_bar.set_message(&format!("{}Extracting...", PACKAGE));

    let _ = fs::remove_dir_all(extract_dir);
    fs::create_dir_all(extract_dir)?;

    let tar_bz2 = File::open(archive)?;
    let tar = BzDecoder::new(BufReader::new(tar_bz2));
    let mut release = Archive::new(tar);
    release.unpack(extract_dir)?;

    progress_bar.finish_and_clear();
    Ok(())
}

/// Reads the supported TARGET triple for the given release
fn load_release_target(release_dir: &Path) -> Result<String, Box<dyn std::error::Error>> {
    use serde_derive::Deserialize;
    #[derive(Deserialize, Debug)]
    pub struct ReleaseVersion {
        pub target: String,
        pub commit: String,
        channel: String,
    }

    let mut version_yml = PathBuf::from(release_dir);
    version_yml.push("solana-release");
    version_yml.push("version.yml");

    let file = File::open(&version_yml)?;
    let version: ReleaseVersion = serde_yaml::from_reader(file)?;
    Ok(version.target)
}

/// Time in seconds since the UNIX_EPOCH
fn timestamp_secs() -> u64 {
    SystemTime::now()
        .duration_since(SystemTime::UNIX_EPOCH)
        .unwrap()
        .as_secs()
}

/// Create an empty update manifest for the given `update_manifest_keypair` if it doesn't already
/// exist on the cluster
fn new_update_manifest(
    rpc_client: &RpcClient,
    from_keypair: &Keypair,
    update_manifest_keypair: &Keypair,
) -> Result<(), Box<dyn std::error::Error>> {
    if rpc_client
        .get_account_data(&update_manifest_keypair.pubkey())
        .is_err()
    {
        let (recent_blockhash, _fee_calculator) = rpc_client.get_recent_blockhash()?;

        let lamports = rpc_client
            .get_minimum_balance_for_rent_exemption(SignedUpdateManifest::max_space() as usize)?;

        let new_account = config_instruction::create_account::<SignedUpdateManifest>(
            &from_keypair.pubkey(),
            &update_manifest_keypair.pubkey(),
            lamports,
            vec![], // additional keys
        );
        let mut transaction = Transaction::new_unsigned_instructions(new_account);
        let signers = [from_keypair, update_manifest_keypair];
        transaction.sign(&signers, recent_blockhash);

        rpc_client.send_and_confirm_transaction(&mut transaction, &[from_keypair])?;
    }
    Ok(())
}

/// Update the update manifest on the cluster with new content
fn store_update_manifest(
    rpc_client: &RpcClient,
    from_keypair: &Keypair,
    update_manifest_keypair: &Keypair,
    update_manifest: &SignedUpdateManifest,
) -> Result<(), Box<dyn std::error::Error>> {
    let (recent_blockhash, _fee_calculator) = rpc_client.get_recent_blockhash()?;

    let signers = [from_keypair, update_manifest_keypair];
    let instruction = config_instruction::store::<SignedUpdateManifest>(
        &update_manifest_keypair.pubkey(),
        true,   // update_manifest_keypair is signer
        vec![], // additional keys
        update_manifest,
    );

    let message = Message::new_with_payer(vec![instruction], Some(&from_keypair.pubkey()));
    let mut transaction = Transaction::new(&signers, message, recent_blockhash);
    rpc_client.send_and_confirm_transaction(&mut transaction, &[from_keypair])?;
    Ok(())
}

/// Read the current contents of the update manifest from the cluster
fn get_update_manifest(
    rpc_client: &RpcClient,
    update_manifest_pubkey: &Pubkey,
) -> Result<UpdateManifest, String> {
    let data = rpc_client
        .get_account_data(update_manifest_pubkey)
        .map_err(|err| format!("Unable to fetch update manifest: {}", err))?;

    let config_data = get_config_data(&data)
        .map_err(|err| format!("Unable to get at config_data to update manifest: {}", err))?;
    let signed_update_manifest =
        SignedUpdateManifest::deserialize(update_manifest_pubkey, config_data)
            .map_err(|err| format!("Unable to deserialize update manifest: {}", err))?;
    Ok(signed_update_manifest.manifest)
}

/// Bug the user if active_release_bin_dir is not in their PATH
fn check_env_path_for_bin_dir(config: &Config) {
    use std::env;

    let bin_dir = config
        .active_release_bin_dir()
        .canonicalize()
        .unwrap_or_default();
    let found = match env::var_os("PATH") {
        Some(paths) => env::split_paths(&paths).any(|path| {
            if let Ok(path) = path.canonicalize() {
                if path == bin_dir {
                    return true;
                }
            }
            false
        }),
        None => false,
    };

    if !found {
        println!(
            "\nPlease update your PATH environment variable to include the solana programs:\n    PATH=\"{}:$PATH\"\n",
            config.active_release_bin_dir().to_str().unwrap()
        );
    }
}

/// Encodes a UTF-8 string as a null-terminated UCS-2 string in bytes
#[cfg(windows)]
pub fn string_to_winreg_bytes(s: &str) -> Vec<u8> {
    use std::ffi::OsString;
    use std::os::windows::ffi::OsStrExt;
    let v: Vec<_> = OsString::from(format!("{}\x00", s)).encode_wide().collect();
    unsafe { std::slice::from_raw_parts(v.as_ptr() as *const u8, v.len() * 2).to_vec() }
}

// This is used to decode the value of HKCU\Environment\PATH. If that
// key is not Unicode (or not REG_SZ | REG_EXPAND_SZ) then this
// returns null.  The winreg library itself does a lossy unicode
// conversion.
#[cfg(windows)]
pub fn string_from_winreg_value(val: &winreg::RegValue) -> Option<String> {
    use std::slice;
    use winreg::enums::RegType;

    match val.vtype {
        RegType::REG_SZ | RegType::REG_EXPAND_SZ => {
            // Copied from winreg
            let words = unsafe {
                slice::from_raw_parts(val.bytes.as_ptr() as *const u16, val.bytes.len() / 2)
            };
            let mut s = if let Ok(s) = String::from_utf16(words) {
                s
            } else {
                return None;
            };
            while s.ends_with('\u{0}') {
                s.pop();
            }
            Some(s)
        }
        _ => None,
    }
}
// Get the windows PATH variable out of the registry as a String. If
// this returns None then the PATH variable is not Unicode and we
// should not mess with it.
#[cfg(windows)]
fn get_windows_path_var() -> Result<Option<String>, String> {
    use winreg::enums::{HKEY_CURRENT_USER, KEY_READ, KEY_WRITE};
    use winreg::RegKey;

    let root = RegKey::predef(HKEY_CURRENT_USER);
    let environment = root
        .open_subkey_with_flags("Environment", KEY_READ | KEY_WRITE)
        .map_err(|err| format!("Unable to open HKEY_CURRENT_USER\\Environment: {}", err))?;

    let reg_value = environment.get_raw_value("PATH");
    match reg_value {
        Ok(val) => {
            if let Some(s) = string_from_winreg_value(&val) {
                Ok(Some(s))
            } else {
                println!("the registry key HKEY_CURRENT_USER\\Environment\\PATH does not contain valid Unicode. Not modifying the PATH variable");
                return Ok(None);
            }
        }
        Err(ref e) if e.kind() == io::ErrorKind::NotFound => Ok(Some(String::new())),
        Err(e) => Err(e.to_string()),
    }
}

#[cfg(windows)]
fn add_to_path(new_path: &str) -> Result<bool, String> {
    use std::ptr;
    use winapi::shared::minwindef::*;
    use winapi::um::winuser::{
        SendMessageTimeoutA, HWND_BROADCAST, SMTO_ABORTIFHUNG, WM_SETTINGCHANGE,
    };
    use winreg::enums::{RegType, HKEY_CURRENT_USER, KEY_READ, KEY_WRITE};
    use winreg::{RegKey, RegValue};

    let old_path = if let Some(s) = get_windows_path_var()? {
        s
    } else {
        return Ok(false);
    };

    if !old_path.contains(&new_path) {
        let mut new_path = new_path.to_string();
        if !old_path.is_empty() {
            new_path.push_str(";");
            new_path.push_str(&old_path);
        }

        let root = RegKey::predef(HKEY_CURRENT_USER);
        let environment = root
            .open_subkey_with_flags("Environment", KEY_READ | KEY_WRITE)
            .map_err(|err| format!("Unable to open HKEY_CURRENT_USER\\Environment: {}", err))?;

        let reg_value = RegValue {
            bytes: string_to_winreg_bytes(&new_path),
            vtype: RegType::REG_EXPAND_SZ,
        };

        environment
            .set_raw_value("PATH", &reg_value)
            .map_err(|err| format!("Unable set HKEY_CURRENT_USER\\Environment\\PATH: {}", err))?;

        // Tell other processes to update their environment
        unsafe {
            SendMessageTimeoutA(
                HWND_BROADCAST,
                WM_SETTINGCHANGE,
                0 as WPARAM,
                "Environment\0".as_ptr() as LPARAM,
                SMTO_ABORTIFHUNG,
                5000,
                ptr::null_mut(),
            );
        }
    }

    println!(
        "\n{}\n  {}\n\n{}",
        style("The HKEY_CURRENT_USER/Environment/PATH registry key has been modified to include:").bold(),
        new_path,
        style("Future applications will automatically have the correct environment, but you may need to restart your current shell.").bold()
    );
    Ok(true)
}

#[cfg(unix)]
fn add_to_path(new_path: &str) -> Result<bool, String> {
    let shell_export_string = format!(r#"export PATH="{}:$PATH""#, new_path);
    let mut modified_rcfiles = false;

    // Look for sh, bash, and zsh rc files
    let mut rcfiles = vec![dirs::home_dir().map(|p| p.join(".profile"))];
    if let Ok(shell) = std::env::var("SHELL") {
        if shell.contains("zsh") {
            let zdotdir = std::env::var("ZDOTDIR")
                .ok()
                .map(PathBuf::from)
                .or_else(dirs::home_dir);
            let zprofile = zdotdir.map(|p| p.join(".zprofile"));
            rcfiles.push(zprofile);
        }
    }

    if let Some(bash_profile) = dirs::home_dir().map(|p| p.join(".bash_profile")) {
        // Only update .bash_profile if it exists because creating .bash_profile
        // will cause .profile to not be read
        if bash_profile.exists() {
            rcfiles.push(Some(bash_profile));
        }
    }
    let rcfiles = rcfiles.into_iter().filter_map(|f| f.filter(|f| f.exists()));

    // For each rc file, append a PATH entry if not already present
    for rcfile in rcfiles {
        if !rcfile.exists() {
            continue;
        }

        fn read_file(path: &Path) -> io::Result<String> {
            let mut file = fs::OpenOptions::new().read(true).open(path)?;
            let mut contents = String::new();
            io::Read::read_to_string(&mut file, &mut contents)?;
            Ok(contents)
        }

        match read_file(&rcfile) {
            Err(err) => {
                println!("Unable to read {:?}: {}", rcfile, err);
            }
            Ok(contents) => {
                if !contents.contains(&shell_export_string) {
                    println!(
                        "Adding {} to {}",
                        style(&shell_export_string).italic(),
                        style(rcfile.to_str().unwrap()).bold()
                    );

                    fn append_file(dest: &Path, line: &str) -> io::Result<()> {
                        use std::io::Write;
                        let mut dest_file = fs::OpenOptions::new()
                            .write(true)
                            .append(true)
                            .create(true)
                            .open(dest)?;

                        writeln!(&mut dest_file, "{}", line)?;

                        dest_file.sync_data()?;

                        Ok(())
                    }
                    append_file(&rcfile, &shell_export_string).unwrap_or_else(|err| {
                        format!("Unable to append to {:?}: {}", rcfile, err);
                    });
                    modified_rcfiles = true;
                }
            }
        }
    }

    if modified_rcfiles {
        println!(
            "\n{}\n  {}\n",
            style("Close and reopen your terminal to apply the PATH changes or run the following in your existing shell:").bold().blue(),
            shell_export_string
       );
    }

    Ok(modified_rcfiles)
}

pub fn init(
    config_file: &str,
    data_dir: &str,
    json_rpc_url: &str,
    update_manifest_pubkey: &Pubkey,
    no_modify_path: bool,
    explicit_release: Option<ExplicitRelease>,
) -> Result<(), String> {
    let config = {
        // Write new config file only if different, so that running |solana-install init|
        // repeatedly doesn't unnecessarily re-download
        let mut current_config = Config::load(config_file).unwrap_or_default();
        current_config.current_update_manifest = None;
        let config = Config::new(
            data_dir,
            json_rpc_url,
            update_manifest_pubkey,
            explicit_release,
        );
        if current_config != config {
            config.save(config_file)?;
        }
        config
    };

    update(config_file)?;

    let path_modified = if !no_modify_path {
        add_to_path(&config.active_release_bin_dir().to_str().unwrap())?
    } else {
        false
    };

    if !path_modified && !no_modify_path {
        check_env_path_for_bin_dir(&config);
    }
    Ok(())
}

fn github_release_download_url(release_semver: &str) -> String {
    format!(
        "https://github.com/solana-labs/solana/releases/download/v{}/solana-release-{}.tar.bz2",
        release_semver,
        crate::build_env::TARGET
    )
}

fn release_channel_download_url(release_channel: &str) -> String {
    format!(
        "http://release.solana.com/{}/solana-release-{}.tar.bz2",
        release_channel,
        crate::build_env::TARGET
    )
}

pub fn info(config_file: &str, local_info_only: bool) -> Result<Option<UpdateManifest>, String> {
    let config = Config::load(config_file)?;

    println_name_value("Configuration:", &config_file);
    println_name_value(
        "Active release directory:",
        &config.active_release_dir().to_str().unwrap_or("?"),
    );

    if let Some(explicit_release) = &config.explicit_release {
        match explicit_release {
            ExplicitRelease::Semver(release_semver) => {
                println_name_value(&format!("{}Release version:", BULLET), &release_semver);
                println_name_value(
                    &format!("{}Release URL:", BULLET),
                    &github_release_download_url(release_semver),
                );
            }
            ExplicitRelease::Channel(release_channel) => {
                println_name_value(&format!("{}Release channel:", BULLET), &release_channel);
                println_name_value(
                    &format!("{}Release URL:", BULLET),
                    &release_channel_download_url(release_channel),
                );
            }
        }
        return Ok(None);
    }

    println_name_value("JSON RPC URL:", &config.json_rpc_url);
    println_name_value(
        "Update manifest pubkey:",
        &config.update_manifest_pubkey.to_string(),
    );

    fn print_update_manifest(update_manifest: &UpdateManifest) {
        let when = Local.timestamp(update_manifest.timestamp_secs as i64, 0);
        println_name_value(&format!("{}release date:", BULLET), &when.to_string());
        println_name_value(
            &format!("{}download URL:", BULLET),
            &update_manifest.download_url,
        );
    }

    match config.current_update_manifest {
        Some(ref update_manifest) => {
            println_name_value("Installed version:", "");
            print_update_manifest(&update_manifest);
        }
        None => {
            println_name_value("Installed version:", "None");
        }
    }

    if local_info_only {
        Ok(None)
    } else {
        let progress_bar = new_spinner_progress_bar();
        progress_bar.set_message(&format!("{}Checking for updates...", LOOKING_GLASS));
        let rpc_client = RpcClient::new(config.json_rpc_url.clone());
        let manifest = get_update_manifest(&rpc_client, &config.update_manifest_pubkey)?;
        progress_bar.finish_and_clear();

        if Some(&manifest) == config.current_update_manifest.as_ref() {
            println!("\n{}", style("Installation is up to date").italic());
            Ok(None)
        } else {
            println!("\n{}", style("An update is available:").bold());
            print_update_manifest(&manifest);
            Ok(Some(manifest))
        }
    }
}

pub fn deploy(
    json_rpc_url: &str,
    from_keypair_file: &str,
    download_url: &str,
    update_manifest_keypair_file: &str,
) -> Result<(), String> {
    let from_keypair = read_keypair_file(from_keypair_file)
        .map_err(|err| format!("Unable to read {}: {}", from_keypair_file, err))?;
    let update_manifest_keypair = read_keypair_file(update_manifest_keypair_file)
        .map_err(|err| format!("Unable to read {}: {}", update_manifest_keypair_file, err))?;

    println_name_value("JSON RPC URL:", json_rpc_url);
    println_name_value(
        "Update manifest pubkey:",
        &update_manifest_keypair.pubkey().to_string(),
    );

    // Confirm the `json_rpc_url` is good and that `from_keypair` is a valid account
    let rpc_client = RpcClient::new(json_rpc_url.to_string());
    let progress_bar = new_spinner_progress_bar();
    progress_bar.set_message(&format!("{}Checking cluster...", LOOKING_GLASS));
    let balance = rpc_client
        .retry_get_balance(&from_keypair.pubkey(), 5)
        .map_err(|err| {
            format!(
                "Unable to get the account balance of {}: {}",
                from_keypair_file, err
            )
        })?;
    progress_bar.finish_and_clear();
    if balance.unwrap_or(0) == 0 {
        return Err(format!("{} account balance is empty", from_keypair_file));
    }

    // Download the release
    let (temp_dir, temp_archive, temp_archive_sha256) =
        download_to_temp_archive(download_url, None)
            .map_err(|err| format!("Unable to download {}: {}", download_url, err))?;

    if let Ok(update_manifest) = get_update_manifest(&rpc_client, &update_manifest_keypair.pubkey())
    {
        if temp_archive_sha256 == update_manifest.download_sha256 {
            println!(
                "  {}{}",
                INFORMATION,
                style("Update is already deployed").bold()
            );
            return Ok(());
        }
    }

    // Extract it and load the release version metadata
    let temp_release_dir = temp_dir.path().join("archive");
    extract_release_archive(&temp_archive, &temp_release_dir).map_err(|err| {
        format!(
            "Unable to extract {:?} into {:?}: {}",
            temp_archive, temp_release_dir, err
        )
    })?;

    let release_target = load_release_target(&temp_release_dir).map_err(|err| {
        format!(
            "Unable to load release target from {:?}: {}",
            temp_release_dir, err
        )
    })?;

    println_name_value("Update target:", &release_target);

    let progress_bar = new_spinner_progress_bar();
    progress_bar.set_message(&format!("{}Deploying update...", PACKAGE));

    // Construct an update manifest for the release
    let mut update_manifest = SignedUpdateManifest {
        account_pubkey: update_manifest_keypair.pubkey(),
        ..SignedUpdateManifest::default()
    };

    update_manifest.manifest.timestamp_secs = timestamp_secs();
    update_manifest.manifest.download_url = download_url.to_string();
    update_manifest.manifest.download_sha256 = temp_archive_sha256;

    update_manifest.sign(&update_manifest_keypair);
    assert!(update_manifest.verify());

    // Store the new update manifest on the cluster
    new_update_manifest(&rpc_client, &from_keypair, &update_manifest_keypair)
        .map_err(|err| format!("Unable to create update manifest: {}", err))?;
    store_update_manifest(
        &rpc_client,
        &from_keypair,
        &update_manifest_keypair,
        &update_manifest,
    )
    .map_err(|err| format!("Unable to store update manifest: {:?}", err))?;

    progress_bar.finish_and_clear();
    println!("  {}{}", SPARKLE, style("Deployment successful").bold());
    Ok(())
}

#[cfg(windows)]
fn symlink_dir<P: AsRef<Path>, Q: AsRef<Path>>(src: P, dst: Q) -> std::io::Result<()> {
    std::os::windows::fs::symlink_dir(src, dst)
}
#[cfg(not(windows))]
fn symlink_dir<P: AsRef<Path>, Q: AsRef<Path>>(src: P, dst: Q) -> std::io::Result<()> {
    std::os::unix::fs::symlink(src, dst)
}

pub fn update(config_file: &str) -> Result<bool, String> {
    let mut config = Config::load(config_file)?;
    let update_manifest = info(config_file, false)?;

    let release_dir = if let Some(explicit_release) = &config.explicit_release {
        let (download, release_dir) = match explicit_release {
            ExplicitRelease::Semver(release_semver) => {
                let download_url = github_release_download_url(release_semver);
                let release_dir = config.release_dir(&release_semver);
                let download = if release_dir.join(".ok").exists() {
                    // If this release_semver has already been successfully downloaded, no update
                    // needed
                    None
                } else {
                    Some(download_url)
                };
                (download, release_dir)
            }
            ExplicitRelease::Channel(release_channel) => {
                let download_url = release_channel_download_url(release_channel);
                let release_dir = config.release_dir(&release_channel);
                // Note: There's currently no mechanism to check for an updated binary for a release
                // channel so a download always occurs.
                (Some(download_url), release_dir)
            }
        };

        if let Some(download_url) = download {
            let (_temp_dir, temp_archive, _temp_archive_sha256) =
                download_to_temp_archive(&download_url, None)
                    .map_err(|err| format!("Unable to download {}: {}", download_url, err))?;
            extract_release_archive(&temp_archive, &release_dir).map_err(|err| {
                format!(
                    "Unable to extract {:?} to {:?}: {}",
                    temp_archive, release_dir, err
                )
            })?;
            let _ = fs::create_dir_all(release_dir.join(".ok"));
        }

        release_dir
    } else {
        if update_manifest.is_none() {
            return Ok(false);
        }
        let update_manifest = update_manifest.unwrap();

        if timestamp_secs()
            < u64::from_str_radix(crate::build_env::BUILD_SECONDS_SINCE_UNIX_EPOCH, 10).unwrap()
        {
            return Err("Unable to update as system time seems unreliable".to_string());
        }

        if let Some(ref current_update_manifest) = config.current_update_manifest {
            if update_manifest.timestamp_secs < current_update_manifest.timestamp_secs {
                return Err("Unable to update to an older version".to_string());
            }
        }
        let release_dir = config.release_dir(&update_manifest.download_sha256.to_string());
        let (_temp_dir, temp_archive, _temp_archive_sha256) = download_to_temp_archive(
            &update_manifest.download_url,
            Some(&update_manifest.download_sha256),
        )
        .map_err(|err| {
            format!(
                "Unable to download {}: {}",
                update_manifest.download_url, err
            )
        })?;
        extract_release_archive(&temp_archive, &release_dir).map_err(|err| {
            format!(
                "Unable to extract {:?} to {:?}: {}",
                temp_archive, release_dir, err
            )
        })?;

        config.current_update_manifest = Some(update_manifest);
        release_dir
    };

    let release_target = load_release_target(&release_dir).map_err(|err| {
        format!(
            "Unable to load release target from {:?}: {}",
            release_dir, err
        )
    })?;

    if release_target != crate::build_env::TARGET {
        return Err(format!("Incompatible update target: {}", release_target));
    }

    let _ = fs::remove_dir_all(config.active_release_dir());
    symlink_dir(
        release_dir.join("solana-release"),
        config.active_release_dir(),
    )
    .map_err(|err| {
        format!(
            "Unable to symlink {:?} to {:?}: {}",
            release_dir,
            config.active_release_dir(),
            err
        )
    })?;

    config.save(config_file)?;

    println!("  {}{}", SPARKLE, style("Update successful").bold());
    Ok(true)
}

pub fn run(
    config_file: &str,
    program_name: &str,
    program_arguments: Vec<&str>,
) -> Result<(), String> {
    let config = Config::load(config_file)?;

    let mut full_program_path = config.active_release_bin_dir().join(program_name);
    if cfg!(windows) && full_program_path.extension().is_none() {
        full_program_path.set_extension("exe");
    }

    if !full_program_path.exists() {
        return Err(format!(
            "{} does not exist",
            full_program_path.to_str().unwrap()
        ));
    }

    let mut child_option: Option<std::process::Child> = None;
    let mut now = Instant::now();

    let (signal_sender, signal_receiver) = mpsc::channel();
    ctrlc::set_handler(move || {
        let _ = signal_sender.send(());
    })
    .expect("Error setting Ctrl-C handler");

    loop {
        child_option = match child_option {
            Some(mut child) => match child.try_wait() {
                Ok(Some(status)) => {
                    println_name_value(
                        &format!("{} exited with:", program_name),
                        &status.to_string(),
                    );
                    None
                }
                Ok(None) => Some(child),
                Err(err) => {
                    eprintln!("Error attempting to wait for program to exit: {}", err);
                    None
                }
            },
            None => {
                match std::process::Command::new(&full_program_path)
                    .args(&program_arguments)
                    .spawn()
                {
                    Ok(child) => Some(child),
                    Err(err) => {
                        eprintln!("Failed to spawn {}: {:?}", program_name, err);
                        None
                    }
                }
            }
        };

        if config.explicit_release.is_none() && now.elapsed().as_secs() > config.update_poll_secs {
            match update(config_file) {
                Ok(true) => {
                    // Update successful, kill current process so it will be restart
                    if let Some(ref mut child) = child_option {
                        stop_process(child).unwrap_or_else(|err| {
                            eprintln!("Failed to stop child: {:?}", err);
                        });
                    }
                }
                Ok(false) => {} // No update available
                Err(err) => {
                    eprintln!("Failed to apply update: {:?}", err);
                }
            };
            now = Instant::now();
        }

        if let Ok(()) = signal_receiver.recv_timeout(Duration::from_secs(1)) {
            // Handle SIGTERM...
            if let Some(ref mut child) = child_option {
                stop_process(child).unwrap_or_else(|err| {
                    eprintln!("Failed to stop child: {:?}", err);
                });
            }
            std::process::exit(0);
        }
    }
}
