canic_host/

icp.rs

use std::{
    env,
    error::Error,
    fmt,
    io::{self, Read, Write},
    path::{Path, PathBuf},
    process::{Command, Stdio},
    thread,
};

use serde::{Deserialize, Serialize};

const LOCAL_NETWORK: &str = "local";
pub(crate) const CANIC_ICP_LOCAL_NETWORK_URL_ENV: &str = "CANIC_ICP_LOCAL_NETWORK_URL";
pub(crate) const CANIC_ICP_LOCAL_ROOT_KEY_ENV: &str = "CANIC_ICP_LOCAL_ROOT_KEY";

///
/// IcpRawOutput
///

#[derive(Clone, Debug, Eq, PartialEq)]
pub struct IcpRawOutput {
    pub success: bool,
    pub status: String,
    pub stdout: Vec<u8>,
    pub stderr: Vec<u8>,
}

///
/// IcpCommandError
///

#[derive(Debug)]
pub enum IcpCommandError {
    Io(std::io::Error),
    Failed {
        command: String,
        stderr: String,
    },
    Json {
        command: String,
        output: String,
        source: serde_json::Error,
    },
    SnapshotIdUnavailable {
        output: String,
    },
}

impl fmt::Display for IcpCommandError {
    // Render ICP CLI command failures with the command line and captured diagnostics.
    fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            Self::Io(err) => write!(formatter, "{err}"),
            Self::Failed { command, stderr } => {
                write!(formatter, "icp command failed: {command}\n{stderr}")
            }
            Self::Json {
                command,
                output,
                source,
            } => {
                write!(
                    formatter,
                    "could not parse icp json output for {command}: {source}\n{output}"
                )
            }
            Self::SnapshotIdUnavailable { output } => {
                write!(
                    formatter,
                    "could not parse snapshot id from icp output: {output}"
                )
            }
        }
    }
}

impl Error for IcpCommandError {
    // Preserve the underlying I/O error as the source when command execution fails locally.
    fn source(&self) -> Option<&(dyn Error + 'static)> {
        match self {
            Self::Io(err) => Some(err),
            Self::Json { source, .. } => Some(source),
            Self::Failed { .. } | Self::SnapshotIdUnavailable { .. } => None,
        }
    }
}

impl From<std::io::Error> for IcpCommandError {
    // Convert process-spawn failures into the shared ICP CLI command error type.
    fn from(err: std::io::Error) -> Self {
        Self::Io(err)
    }
}

///
/// IcpCli
///

#[derive(Clone, Debug, Eq, PartialEq)]
pub struct IcpCli {
    executable: String,
    environment: Option<String>,
    network: Option<String>,
    cwd: Option<PathBuf>,
}

///
/// IcpSnapshotCreateReceipt
///

#[derive(Clone, Debug, Deserialize, Eq, PartialEq, Serialize)]
pub struct IcpSnapshotCreateReceipt {
    pub snapshot_id: String,
    pub taken_at_timestamp: Option<u64>,
    pub total_size_bytes: Option<u64>,
}

///
/// IcpSnapshotUploadReceipt
///

#[derive(Clone, Debug, Deserialize, Eq, PartialEq, Serialize)]
pub struct IcpSnapshotUploadReceipt {
    pub snapshot_id: String,
}

///
/// IcpCanisterStatusReport
///

#[derive(Clone, Debug, Deserialize, Eq, PartialEq, Serialize)]
pub struct IcpCanisterStatusReport {
    pub id: String,
    pub name: Option<String>,
    pub status: String,
    pub settings: Option<IcpCanisterStatusSettings>,
    pub module_hash: Option<String>,
    pub memory_size: Option<String>,
    pub cycles: Option<String>,
    pub reserved_cycles: Option<String>,
    pub idle_cycles_burned_per_day: Option<String>,
}

///
/// IcpCanisterStatusSettings
///

#[derive(Clone, Debug, Deserialize, Eq, PartialEq, Serialize)]
pub struct IcpCanisterStatusSettings {
    #[serde(default)]
    pub controllers: Vec<String>,
    pub compute_allocation: Option<String>,
    pub memory_allocation: Option<String>,
    pub freezing_threshold: Option<String>,
    pub reserved_cycles_limit: Option<String>,
    pub wasm_memory_limit: Option<String>,
    pub wasm_memory_threshold: Option<String>,
    pub log_memory_limit: Option<String>,
}

impl IcpCli {
    /// Build an ICP CLI command context from an executable path and optional target.
    #[must_use]
    pub fn new(
        executable: impl Into<String>,
        environment: Option<String>,
        network: Option<String>,
    ) -> Self {
        Self {
            executable: executable.into(),
            environment,
            network,
            cwd: None,
        }
    }

    /// Return a copy of this ICP CLI context rooted at one project directory.
    #[must_use]
    pub fn with_cwd(mut self, cwd: impl Into<PathBuf>) -> Self {
        self.cwd = Some(cwd.into());
        self
    }

    /// Return the optional ICP environment name carried by this command context.
    #[must_use]
    pub fn environment(&self) -> Option<&str> {
        self.environment.as_deref()
    }

    /// Return the optional direct network name carried by this command context.
    #[must_use]
    pub fn network(&self) -> Option<&str> {
        self.network.as_deref()
    }

    /// Build a base ICP CLI command from this context.
    #[must_use]
    pub fn command(&self) -> Command {
        let mut command = Command::new(&self.executable);
        if let Some(cwd) = &self.cwd {
            command.current_dir(cwd);
        }
        command
    }

    /// Build a base ICP CLI command rooted at one workspace directory.
    #[must_use]
    pub fn command_in(&self, cwd: &Path) -> Command {
        let mut command = self.command();
        command.current_dir(cwd);
        command
    }

    /// Build an `icp canister ...` command with optional environment args applied.
    #[must_use]
    pub fn canister_command(&self) -> Command {
        let mut command = self.command();
        command.arg("canister");
        command
    }

    /// Resolve the installed ICP CLI version.
    pub fn version(&self) -> Result<String, IcpCommandError> {
        let mut command = self.command();
        command.arg("--version");
        run_output(&mut command)
    }

    /// Start the local ICP replica.
    pub fn local_replica_start(
        &self,
        background: bool,
        debug: bool,
    ) -> Result<String, IcpCommandError> {
        let mut command = self.local_replica_command("start");
        run_local_replica_start_command(&mut command, background, debug)
    }

    /// Start the local ICP replica from one ICP project root.
    pub fn local_replica_start_in(
        &self,
        cwd: &Path,
        background: bool,
        debug: bool,
    ) -> Result<String, IcpCommandError> {
        let mut command = self.local_replica_command_in("start", cwd);
        run_local_replica_start_command(&mut command, background, debug)
    }

    /// Return local ICP replica status.
    pub fn local_replica_status(&self, debug: bool) -> Result<String, IcpCommandError> {
        let mut command = self.local_replica_command("status");
        add_debug_arg(&mut command, debug);
        run_output_with_stderr(&mut command)
    }

    /// Return local ICP replica status from one ICP project root.
    pub fn local_replica_status_in(
        &self,
        cwd: &Path,
        debug: bool,
    ) -> Result<String, IcpCommandError> {
        let mut command = self.local_replica_command_in("status", cwd);
        add_debug_arg(&mut command, debug);
        run_output_with_stderr(&mut command)
    }

    /// Return local ICP replica status as the ICP CLI JSON payload.
    pub fn local_replica_status_json(
        &self,
        debug: bool,
    ) -> Result<serde_json::Value, IcpCommandError> {
        let mut command = self.local_replica_command("status");
        add_debug_arg(&mut command, debug);
        command.arg("--json");
        run_json(&mut command)
    }

    /// Return local ICP replica status JSON from one ICP project root.
    pub fn local_replica_status_json_in(
        &self,
        cwd: &Path,
        debug: bool,
    ) -> Result<serde_json::Value, IcpCommandError> {
        let mut command = self.local_replica_command_in("status", cwd);
        add_debug_arg(&mut command, debug);
        command.arg("--json");
        run_json(&mut command)
    }

    /// Return whether this project owns a running local ICP replica.
    pub fn local_replica_project_running(&self, debug: bool) -> Result<bool, IcpCommandError> {
        let mut command = self.local_replica_command("status");
        add_debug_arg(&mut command, debug);
        run_success(&mut command)
    }

    /// Return whether one ICP project root owns a running local ICP replica.
    pub fn local_replica_project_running_in(
        &self,
        cwd: &Path,
        debug: bool,
    ) -> Result<bool, IcpCommandError> {
        let mut command = self.local_replica_command_in("status", cwd);
        add_debug_arg(&mut command, debug);
        run_success(&mut command)
    }

    /// Return whether the local ICP replica responds to ping.
    pub fn local_replica_ping(&self, debug: bool) -> Result<bool, IcpCommandError> {
        let mut command = self.local_replica_command("ping");
        add_debug_arg(&mut command, debug);
        run_success(&mut command)
    }

    /// Stop the local ICP replica.
    pub fn local_replica_stop(&self, debug: bool) -> Result<String, IcpCommandError> {
        let mut command = self.local_replica_command("stop");
        add_debug_arg(&mut command, debug);
        run_output_with_stderr(&mut command)
    }

    /// Stop the local ICP replica from one ICP project root.
    pub fn local_replica_stop_in(
        &self,
        cwd: &Path,
        debug: bool,
    ) -> Result<String, IcpCommandError> {
        let mut command = self.local_replica_command_in("stop", cwd);
        add_debug_arg(&mut command, debug);
        run_output_with_stderr(&mut command)
    }

    /// Render a local replica start command.
    #[must_use]
    pub fn local_replica_start_display(&self, background: bool, debug: bool) -> String {
        let mut command = self.local_replica_command("start");
        add_debug_arg(&mut command, debug);
        if background {
            command.arg("--background");
        }
        command_display(&command)
    }

    /// Render a local replica status command.
    #[must_use]
    pub fn local_replica_status_display(&self, debug: bool) -> String {
        let mut command = self.local_replica_command("status");
        add_debug_arg(&mut command, debug);
        command_display(&command)
    }

    /// Render a local replica stop command.
    #[must_use]
    pub fn local_replica_stop_display(&self, debug: bool) -> String {
        let mut command = self.local_replica_command("stop");
        add_debug_arg(&mut command, debug);
        command_display(&command)
    }

    fn local_replica_command(&self, action: &str) -> Command {
        let mut command = self.command();
        command.args(["network", action, LOCAL_NETWORK]);
        command
    }

    fn local_replica_command_in(&self, action: &str, cwd: &Path) -> Command {
        let mut command = self.command_in(cwd);
        command.args(["network", action, LOCAL_NETWORK]);
        command
    }

    /// Call one canister method with optional JSON output.
    pub fn canister_call_output(
        &self,
        canister: &str,
        method: &str,
        output: Option<&str>,
    ) -> Result<String, IcpCommandError> {
        let mut command = self.canister_command();
        command.args(["call", canister, method]);
        command.arg("()");
        if let Some(output) = output {
            add_output_arg(&mut command, output);
        }
        self.add_target_args(&mut command);
        run_output(&mut command)
    }

    /// Call one canister method with an explicit Candid argument and optional JSON output.
    pub fn canister_call_arg_output(
        &self,
        canister: &str,
        method: &str,
        arg: &str,
        output: Option<&str>,
    ) -> Result<String, IcpCommandError> {
        let mut command = self.canister_command();
        command.args(["call", canister, method]);
        command.arg(arg);
        if let Some(output) = output {
            add_output_arg(&mut command, output);
        }
        self.add_target_args(&mut command);
        run_output(&mut command)
    }

    /// Query one canister method with no arguments and optional JSON output.
    pub fn canister_query_output(
        &self,
        canister: &str,
        method: &str,
        output: Option<&str>,
    ) -> Result<String, IcpCommandError> {
        let mut command = self.canister_command();
        command.args(["call", canister, method]);
        command.arg("()");
        command.arg("--query");
        if let Some(output) = output {
            add_output_arg(&mut command, output);
        }
        self.add_target_args(&mut command);
        run_output(&mut command)
    }

    /// Query one canister method with an explicit Candid argument and optional JSON output.
    pub fn canister_query_arg_output(
        &self,
        canister: &str,
        method: &str,
        arg: &str,
        output: Option<&str>,
    ) -> Result<String, IcpCommandError> {
        let mut command = self.canister_command();
        command.args(["call", canister, method]);
        command.arg(arg);
        command.arg("--query");
        if let Some(output) = output {
            add_output_arg(&mut command, output);
        }
        self.add_target_args(&mut command);
        run_output(&mut command)
    }

    /// Read one canister metadata section.
    pub fn canister_metadata_output(
        &self,
        canister: &str,
        metadata_name: &str,
    ) -> Result<String, IcpCommandError> {
        let mut command = self.canister_command();
        command.args(["metadata", canister, metadata_name]);
        self.add_target_args(&mut command);
        run_output(&mut command)
    }

    /// Return one canister status report.
    pub fn canister_status(&self, canister: &str) -> Result<String, IcpCommandError> {
        let mut command = self.canister_command();
        command.args(["status", canister]);
        self.add_target_args(&mut command);
        run_output(&mut command)
    }

    /// Top up one canister with cycles.
    pub fn canister_top_up_output(
        &self,
        canister: &str,
        amount_cycles: u128,
    ) -> Result<String, IcpCommandError> {
        let mut command = self.canister_command();
        command.args(["top-up", "--amount"]);
        command.arg(amount_cycles.to_string());
        command.arg(canister);
        self.add_target_args(&mut command);
        run_output_with_stderr(&mut command)
    }

    /// Return one canister status report from ICP CLI JSON output.
    pub fn canister_status_report(
        &self,
        canister: &str,
    ) -> Result<IcpCanisterStatusReport, IcpCommandError> {
        let mut command = self.canister_command();
        command.args(["status", canister]);
        command.arg("--json");
        self.add_target_args(&mut command);
        run_json(&mut command)
    }

    /// Create one canister snapshot and return the ICP CLI JSON receipt.
    pub fn snapshot_create_receipt(
        &self,
        canister: &str,
    ) -> Result<IcpSnapshotCreateReceipt, IcpCommandError> {
        let mut command = self.canister_command();
        command.args(["snapshot", "create", canister]);
        command.arg("--json");
        self.add_target_args(&mut command);
        run_json(&mut command)
    }

    /// Create one canister snapshot and resolve the resulting snapshot id.
    pub fn snapshot_create_id(&self, canister: &str) -> Result<String, IcpCommandError> {
        Ok(self.snapshot_create_receipt(canister)?.snapshot_id)
    }

    /// Stop one canister.
    pub fn stop_canister(&self, canister: &str) -> Result<(), IcpCommandError> {
        let mut command = self.canister_command();
        command.args(["stop", canister]);
        self.add_target_args(&mut command);
        run_status(&mut command)
    }

    /// Start one canister.
    pub fn start_canister(&self, canister: &str) -> Result<(), IcpCommandError> {
        let mut command = self.canister_command();
        command.args(["start", canister]);
        self.add_target_args(&mut command);
        run_status(&mut command)
    }

    /// Download one canister snapshot into an artifact directory.
    pub fn snapshot_download(
        &self,
        canister: &str,
        snapshot_id: &str,
        artifact_path: &Path,
    ) -> Result<(), IcpCommandError> {
        let mut command = self.canister_command();
        command.args(["snapshot", "download", canister, snapshot_id, "--output"]);
        command.arg(artifact_path);
        self.add_target_args(&mut command);
        run_status(&mut command)
    }

    /// Upload one snapshot artifact and return the uploaded snapshot id.
    pub fn snapshot_upload(
        &self,
        canister: &str,
        artifact_path: &Path,
    ) -> Result<String, IcpCommandError> {
        Ok(self
            .snapshot_upload_receipt(canister, artifact_path)?
            .snapshot_id)
    }

    /// Upload one snapshot artifact and return the ICP CLI JSON receipt.
    pub fn snapshot_upload_receipt(
        &self,
        canister: &str,
        artifact_path: &Path,
    ) -> Result<IcpSnapshotUploadReceipt, IcpCommandError> {
        let mut command = self.canister_command();
        command.args(["snapshot", "upload", canister, "--input"]);
        command.arg(artifact_path);
        command.arg("--resume");
        command.arg("--json");
        self.add_target_args(&mut command);
        run_json(&mut command)
    }

    /// Restore one uploaded snapshot onto a canister.
    pub fn snapshot_restore(
        &self,
        canister: &str,
        snapshot_id: &str,
    ) -> Result<(), IcpCommandError> {
        let mut command = self.canister_command();
        command.args(["snapshot", "restore", canister, snapshot_id]);
        self.add_target_args(&mut command);
        run_status(&mut command)
    }

    /// Render a dry-run snapshot-create command.
    #[must_use]
    pub fn snapshot_create_display(&self, canister: &str) -> String {
        let mut command = self.canister_command();
        command.args(["snapshot", "create", canister]);
        command.arg("--json");
        self.add_target_args(&mut command);
        command_display(&command)
    }

    /// Render a dry-run snapshot-download command.
    #[must_use]
    pub fn snapshot_download_display(
        &self,
        canister: &str,
        snapshot_id: &str,
        artifact_path: &Path,
    ) -> String {
        let mut command = self.canister_command();
        command.args(["snapshot", "download", canister, snapshot_id, "--output"]);
        command.arg(artifact_path);
        self.add_target_args(&mut command);
        command_display(&command)
    }

    /// Render a dry-run snapshot-upload command.
    #[must_use]
    pub fn snapshot_upload_display(&self, canister: &str, artifact_path: &Path) -> String {
        let mut command = self.canister_command();
        command.args(["snapshot", "upload", canister, "--input"]);
        command.arg(artifact_path);
        command.arg("--resume");
        command.arg("--json");
        self.add_target_args(&mut command);
        command_display(&command)
    }

    /// Render a dry-run snapshot-restore command.
    #[must_use]
    pub fn snapshot_restore_display(&self, canister: &str, snapshot_id: &str) -> String {
        let mut command = self.canister_command();
        command.args(["snapshot", "restore", canister, snapshot_id]);
        self.add_target_args(&mut command);
        command_display(&command)
    }

    /// Render a dry-run stop command.
    #[must_use]
    pub fn stop_canister_display(&self, canister: &str) -> String {
        let mut command = self.canister_command();
        command.args(["stop", canister]);
        self.add_target_args(&mut command);
        command_display(&command)
    }

    /// Render a dry-run start command.
    #[must_use]
    pub fn start_canister_display(&self, canister: &str) -> String {
        let mut command = self.canister_command();
        command.args(["start", canister]);
        self.add_target_args(&mut command);
        command_display(&command)
    }

    /// Render a dry-run top-up command.
    #[must_use]
    pub fn canister_top_up_display(&self, canister: &str, amount_cycles: u128) -> String {
        let mut command = self.canister_command();
        command.args(["top-up", "--amount"]);
        command.arg(amount_cycles.to_string());
        command.arg(canister);
        self.add_target_args(&mut command);
        command_display(&command)
    }

    /// Render a dry-run no-argument query call.
    #[must_use]
    pub fn canister_query_output_display(
        &self,
        canister: &str,
        method: &str,
        output: Option<&str>,
    ) -> String {
        let mut command = self.canister_command();
        command.args(["call", canister, method]);
        command.arg("()");
        command.arg("--query");
        if let Some(output) = output {
            add_output_arg(&mut command, output);
        }
        self.add_target_args(&mut command);
        command_display(&command)
    }

    /// Render a dry-run update call with an explicit Candid argument.
    #[must_use]
    pub fn canister_call_arg_output_display(
        &self,
        canister: &str,
        method: &str,
        arg: &str,
        output: Option<&str>,
    ) -> String {
        let mut command = self.canister_command();
        command.args(["call", canister, method]);
        command.arg(arg);
        if let Some(output) = output {
            add_output_arg(&mut command, output);
        }
        self.add_target_args(&mut command);
        command_display(&command)
    }

    fn add_target_args(&self, command: &mut Command) {
        add_target_args(command, self.environment(), self.network());
    }
}

/// Build a base `icp` command with the default executable.
#[must_use]
pub fn default_command() -> Command {
    IcpCli::new("icp", None, None).command()
}

/// Build a base `icp` command rooted at one workspace directory.
#[must_use]
pub fn default_command_in(cwd: &Path) -> Command {
    IcpCli::new("icp", None, None).command_in(cwd)
}

/// Add optional ICP CLI target arguments, preferring named environments.
pub fn add_target_args(command: &mut Command, environment: Option<&str>, network: Option<&str>) {
    if let Some(environment) = environment {
        if environment == LOCAL_NETWORK
            && let Some(url) = env::var_os(CANIC_ICP_LOCAL_NETWORK_URL_ENV)
        {
            command.env_remove("ICP_ENVIRONMENT");
            command.arg("-n").arg(url);
            if let Some(root_key) = env::var_os(CANIC_ICP_LOCAL_ROOT_KEY_ENV) {
                command.arg("-k").arg(root_key);
            }
            return;
        }
        command.args(["-e", environment]);
    } else if let Some(network) = network {
        command.args(["-n", network]);
    }
}

/// Add ICP CLI output formatting, handling JSON as its own flag.
pub fn add_output_arg(command: &mut Command, output: &str) {
    if output == "json" {
        command.arg("--json");
    } else {
        command.args(["--output", output]);
    }
}

/// Add ICP CLI debug logging when requested.
pub fn add_debug_arg(command: &mut Command, debug: bool) {
    if debug {
        command.arg("--debug");
    }
}

fn run_local_replica_start_command(
    command: &mut Command,
    background: bool,
    debug: bool,
) -> Result<String, IcpCommandError> {
    add_debug_arg(command, debug);
    if background {
        command.arg("--background");
        return run_output_with_stderr(command);
    }
    run_status_inherit(command)?;
    Ok(String::new())
}

/// Execute a command and capture trimmed stdout.
pub fn run_output(command: &mut Command) -> Result<String, IcpCommandError> {
    let display = command_display(command);
    let output = command.output()?;
    if output.status.success() {
        Ok(String::from_utf8_lossy(&output.stdout).trim().to_string())
    } else {
        Err(IcpCommandError::Failed {
            command: display,
            stderr: command_stderr(&output),
        })
    }
}

/// Execute a command and capture stdout plus stderr on success.
pub fn run_output_with_stderr(command: &mut Command) -> Result<String, IcpCommandError> {
    let display = command_display(command);
    let output = command.output()?;
    if output.status.success() {
        let mut text = String::from_utf8_lossy(&output.stdout).to_string();
        text.push_str(&String::from_utf8_lossy(&output.stderr));
        Ok(text.trim().to_string())
    } else {
        Err(IcpCommandError::Failed {
            command: display,
            stderr: command_stderr(&output),
        })
    }
}

/// Execute a command and parse successful stdout as JSON.
pub fn run_json<T>(command: &mut Command) -> Result<T, IcpCommandError>
where
    T: serde::de::DeserializeOwned,
{
    let display = command_display(command);
    let output = command.output()?;
    if output.status.success() {
        let stdout = String::from_utf8_lossy(&output.stdout).trim().to_string();
        serde_json::from_str(&stdout).map_err(|source| IcpCommandError::Json {
            command: display,
            output: stdout,
            source,
        })
    } else {
        Err(IcpCommandError::Failed {
            command: display,
            stderr: command_stderr(&output),
        })
    }
}

/// Execute a command and require a successful status.
pub fn run_status(command: &mut Command) -> Result<(), IcpCommandError> {
    let display = command_display(command);
    let output = command.output()?;
    if output.status.success() {
        Ok(())
    } else {
        Err(IcpCommandError::Failed {
            command: display,
            stderr: command_stderr(&output),
        })
    }
}

/// Execute a command with inherited terminal I/O and require a successful status.
pub fn run_status_inherit(command: &mut Command) -> Result<(), IcpCommandError> {
    let display = command_display(command);
    let mut child = command
        .stdout(Stdio::inherit())
        .stderr(Stdio::piped())
        .spawn()?;
    let stderr_handle = child
        .stderr
        .take()
        .map(|stderr| thread::spawn(move || stream_and_capture_stderr(stderr)));
    let status = child.wait()?;
    let stderr = match stderr_handle {
        Some(handle) => match handle.join() {
            Ok(result) => result?,
            Err(_) => Vec::new(),
        },
        None => Vec::new(),
    };
    if status.success() {
        Ok(())
    } else {
        let stderr = if stderr.is_empty() {
            format!("command exited with status {}", exit_status_label(status))
        } else {
            String::from_utf8_lossy(&stderr).to_string()
        };
        Err(IcpCommandError::Failed {
            command: display,
            stderr,
        })
    }
}

fn stream_and_capture_stderr(mut stderr: impl Read) -> io::Result<Vec<u8>> {
    let mut captured = Vec::new();
    let mut buffer = [0_u8; 8192];
    let mut terminal = io::stderr().lock();
    loop {
        let read = stderr.read(&mut buffer)?;
        if read == 0 {
            break;
        }
        terminal.write_all(&buffer[..read])?;
        captured.extend_from_slice(&buffer[..read]);
    }
    terminal.flush()?;
    Ok(captured)
}

/// Execute a command and return whether it exits successfully.
pub fn run_success(command: &mut Command) -> Result<bool, IcpCommandError> {
    Ok(command.output()?.status.success())
}

/// Execute a rendered ICP CLI command and return raw process output.
pub fn run_raw_output(program: &str, args: &[String]) -> Result<IcpRawOutput, std::io::Error> {
    let output = Command::new(program).args(args).output()?;
    Ok(IcpRawOutput {
        success: output.status.success(),
        status: exit_status_label(output.status),
        stdout: output.stdout,
        stderr: output.stderr,
    })
}

/// Render a command for diagnostics and dry-run previews.
#[must_use]
pub fn command_display(command: &Command) -> String {
    let mut parts = vec![command.get_program().to_string_lossy().to_string()];
    parts.extend(
        command
            .get_args()
            .map(|arg| arg.to_string_lossy().to_string()),
    );
    parts.join(" ")
}

/// Parse a likely snapshot id from `icp canister snapshot create` output.
#[must_use]
pub fn parse_snapshot_id(output: &str) -> Option<String> {
    let trimmed = output.trim();
    if is_snapshot_id_token(trimmed) {
        return Some(trimmed.to_string());
    }

    output
        .lines()
        .flat_map(|line| {
            line.split(|c: char| c.is_whitespace() || matches!(c, '"' | '\'' | ':' | ','))
        })
        .find(|part| is_snapshot_id_token(part))
        .map(str::to_string)
}

// ICP snapshot ids are rendered as even-length hexadecimal blobs.
fn is_snapshot_id_token(value: &str) -> bool {
    !value.is_empty()
        && value.len().is_multiple_of(2)
        && value.chars().all(|c| c.is_ascii_hexdigit())
}

// Prefer stderr, but keep stdout diagnostics for CLI commands that report there.
fn command_stderr(output: &std::process::Output) -> String {
    let stderr = String::from_utf8_lossy(&output.stderr);
    if stderr.trim().is_empty() {
        String::from_utf8_lossy(&output.stdout).to_string()
    } else {
        stderr.to_string()
    }
}

// Render process exit status without relying on platform-specific internals.
fn exit_status_label(status: std::process::ExitStatus) -> String {
    status
        .code()
        .map_or_else(|| "signal".to_string(), |code| code.to_string())
}

#[cfg(test)]
mod tests {
    use super::*;

    // Keep generated commands tied to ICP CLI environments when one is selected.
    #[test]
    fn renders_environment_target() {
        let icp = IcpCli::new("icp", Some("staging".to_string()), Some("ic".to_string()));

        assert_eq!(
            icp.snapshot_download_display("root", "snap-1", Path::new("backups/root")),
            "icp canister snapshot download root snap-1 --output backups/root -e staging"
        );
    }

    // Keep direct network targeting available for local and ad hoc command contexts.
    #[test]
    fn renders_network_target() {
        let icp = IcpCli::new("icp", None, Some("ic".to_string()));

        assert_eq!(
            icp.snapshot_create_display("aaaaa-aa"),
            "icp canister snapshot create aaaaa-aa --json -n ic"
        );
    }

    // Keep local replica lifecycle commands explicit and project-scoped.
    #[test]
    fn renders_local_replica_commands() {
        let icp = IcpCli::new("icp", None, None);

        assert_eq!(
            icp.local_replica_start_display(true, false),
            "icp network start local --background"
        );
        assert_eq!(
            icp.local_replica_start_display(false, false),
            "icp network start local"
        );
        assert_eq!(
            icp.local_replica_start_display(false, true),
            "icp network start local --debug"
        );
        assert_eq!(
            icp.local_replica_status_display(false),
            "icp network status local"
        );
        assert_eq!(
            icp.local_replica_status_display(true),
            "icp network status local --debug"
        );
        assert_eq!(
            icp.local_replica_stop_display(false),
            "icp network stop local"
        );
        assert_eq!(
            icp.local_replica_stop_display(true),
            "icp network stop local --debug"
        );
    }

    // Ensure restore planning uses the ICP CLI upload/restore flow.
    #[test]
    fn renders_snapshot_restore_flow() {
        let icp = IcpCli::new("icp", Some("prod".to_string()), None);

        assert_eq!(
            icp.snapshot_upload_display("root", Path::new("artifact")),
            "icp canister snapshot upload root --input artifact --resume --json -e prod"
        );
        assert_eq!(
            icp.snapshot_restore_display("root", "uploaded-1"),
            "icp canister snapshot restore root uploaded-1 -e prod"
        );
    }

    // Ensure query helpers do not accidentally issue update calls for read-only endpoint probes.
    #[test]
    fn renders_no_argument_query_call() {
        let icp = IcpCli::new("icp", None, Some("ic".to_string()));

        assert_eq!(
            icp.canister_query_output_display("root", "canic_ready", Some("json")),
            "icp canister call root canic_ready () --query --json -n ic"
        );
    }

    // Ensure update-call previews preserve the explicit Candid argument.
    #[test]
    fn renders_argument_update_call() {
        let icp = IcpCli::new("icp", None, Some("ic".to_string()));

        assert_eq!(
            icp.canister_call_arg_output_display(
                "root",
                "canic_icp_refill",
                "(record { dry_run = true })",
                Some("json")
            ),
            "icp canister call root canic_icp_refill (record { dry_run = true }) --json -n ic"
        );
    }

    // Ensure manual top-ups use the ICP CLI top-up command and selected network.
    #[test]
    fn renders_canister_top_up() {
        let icp = IcpCli::new("icp", None, Some("ic".to_string()));

        assert_eq!(
            icp.canister_top_up_display("aaaaa-aa", 4_000_000_000_000),
            "icp canister top-up --amount 4000000000000 aaaaa-aa -n ic"
        );
    }

    // Ensure snapshot ids can be extracted from common create output.
    #[test]
    fn parses_snapshot_id_from_output() {
        let snapshot_id = parse_snapshot_id("Created snapshot: 0a0b0c0d\n");

        assert_eq!(snapshot_id.as_deref(), Some("0a0b0c0d"));
    }

    // Ensure table units are not mistaken for snapshot ids.
    #[test]
    fn parses_snapshot_id_from_table_output() {
        let output = "\
ID         SIZE       CREATED_AT
0a0b0c0d   1.37 MiB   2026-05-10T17:04:19Z
";

        let snapshot_id = parse_snapshot_id(output);

        assert_eq!(snapshot_id.as_deref(), Some("0a0b0c0d"));
    }

    // Ensure current ICP CLI snapshot JSON receipts parse into the typed host shape.
    #[test]
    fn parses_snapshot_create_receipt_json() {
        let receipt = serde_json::from_str::<IcpSnapshotCreateReceipt>(
            r#"{
  "snapshot_id": "0000000000000000ffffffffffc000020101",
  "taken_at_timestamp": 1778709681897818005,
  "total_size_bytes": 272586987
}"#,
        )
        .expect("parse snapshot receipt");

        assert_eq!(receipt.snapshot_id, "0000000000000000ffffffffffc000020101");
        assert_eq!(receipt.total_size_bytes, Some(272_586_987));
    }

    // Ensure current ICP CLI snapshot upload JSON receipts parse into the typed host shape.
    #[test]
    fn parses_snapshot_upload_receipt_json() {
        let receipt = serde_json::from_str::<IcpSnapshotUploadReceipt>(
            r#"{
  "snapshot_id": "0000000000000000ffffffffffc000020101"
}"#,
        )
        .expect("parse snapshot upload receipt");

        assert_eq!(receipt.snapshot_id, "0000000000000000ffffffffffc000020101");
    }

    // Ensure current ICP CLI status JSON parses into the typed host shape.
    #[test]
    fn parses_canister_status_report_json() {
        let report = serde_json::from_str::<IcpCanisterStatusReport>(
            r#"{
  "id": "t63gs-up777-77776-aaaba-cai",
  "name": "motoko-ex",
  "status": "Running",
  "settings": {
    "controllers": ["zbf4m-zw3nk-6owqc-qmluz-xhwxt-2pkky-xhjy2-kqxor-qzxsn-6d2bz-nae"],
    "compute_allocation": "0"
  },
  "module_hash": "0x66ce5ddcd06f1135c1a04792a2f1b7c3d9e229b977a8fc9762c71ecc5314c9eb",
  "cycles": "1_497_896_187_059"
}"#,
        )
        .expect("parse status report");

        assert_eq!(report.status, "Running");
        assert_eq!(
            report.settings.expect("settings").controllers.as_slice(),
            &["zbf4m-zw3nk-6owqc-qmluz-xhwxt-2pkky-xhjy2-kqxor-qzxsn-6d2bz-nae"]
        );
    }
}