use std::collections::HashMap;
#[cfg(target_os = "windows")]
use std::io;
use test_rpc::{meta::OsVersion, mullvad_daemon::Verbosity};

#[cfg(target_os = "windows")]
use std::{ffi::OsString, path::Path};
#[cfg(target_os = "windows")]
use windows_service::{
    service::{ServiceAccess, ServiceInfo},
    service_manager::{ServiceManager, ServiceManagerAccess},
};

#[cfg(target_os = "linux")]
const SYSTEMD_OVERRIDE_FILE: &str = "/etc/systemd/system/mullvad-daemon.service.d/override.conf";

#[cfg(target_os = "macos")]
const PLIST_OVERRIDE_FILE: &str = "/Library/LaunchDaemons/net.mullvad.daemon.plist";

#[cfg(target_os = "windows")]
const MULLVAD_WIN_REGISTRY: &str = r"SYSTEM\CurrentControlSet\Services\Mullvad VPN";

#[cfg(target_os = "windows")]
pub fn reboot() -> Result<(), test_rpc::Error> {
    use windows_sys::Win32::{
        System::Shutdown::{
            ExitWindowsEx, EWX_REBOOT, SHTDN_REASON_FLAG_PLANNED, SHTDN_REASON_MAJOR_APPLICATION,
            SHTDN_REASON_MINOR_OTHER,
        },
        UI::WindowsAndMessaging::EWX_FORCEIFHUNG,
    };

    grant_shutdown_privilege()?;

    std::thread::spawn(|| {
        std::thread::sleep(std::time::Duration::from_secs(5));

        let shutdown_result = unsafe {
            ExitWindowsEx(
                EWX_FORCEIFHUNG | EWX_REBOOT,
                SHTDN_REASON_MAJOR_APPLICATION
                    | SHTDN_REASON_MINOR_OTHER
                    | SHTDN_REASON_FLAG_PLANNED,
            )
        };

        if shutdown_result == 0 {
            log::error!(
                "Failed to restart test machine: {}",
                io::Error::last_os_error()
            );
            std::process::exit(1);
        }

        std::process::exit(0);
    });

    // NOTE: We do not bother to revoke the privilege.

    Ok(())
}

#[cfg(target_os = "windows")]
fn grant_shutdown_privilege() -> Result<(), test_rpc::Error> {
    use windows_sys::Win32::{
        Foundation::{CloseHandle, HANDLE, LUID},
        Security::{
            AdjustTokenPrivileges, LookupPrivilegeValueW, LUID_AND_ATTRIBUTES,
            SE_PRIVILEGE_ENABLED, TOKEN_ADJUST_PRIVILEGES, TOKEN_PRIVILEGES,
        },
        System::{
            SystemServices::SE_SHUTDOWN_NAME,
            Threading::{GetCurrentProcess, OpenProcessToken},
        },
    };

    let mut privileges = TOKEN_PRIVILEGES {
        PrivilegeCount: 1,
        Privileges: [LUID_AND_ATTRIBUTES {
            Luid: LUID {
                HighPart: 0,
                LowPart: 0,
            },
            Attributes: SE_PRIVILEGE_ENABLED,
        }],
    };

    if unsafe {
        LookupPrivilegeValueW(
            std::ptr::null(),
            SE_SHUTDOWN_NAME,
            &mut privileges.Privileges[0].Luid,
        )
    } == 0
    {
        log::error!(
            "Failed to lookup shutdown privilege LUID: {}",
            io::Error::last_os_error()
        );
        return Err(test_rpc::Error::Syscall);
    }

    let mut token_handle: HANDLE = 0;

    if unsafe {
        OpenProcessToken(
            GetCurrentProcess(),
            TOKEN_ADJUST_PRIVILEGES,
            &mut token_handle,
        )
    } == 0
    {
        log::error!("OpenProcessToken() failed: {}", io::Error::last_os_error());
        return Err(test_rpc::Error::Syscall);
    }

    let result = unsafe {
        AdjustTokenPrivileges(
            token_handle,
            0,
            &privileges,
            0,
            std::ptr::null_mut(),
            std::ptr::null_mut(),
        )
    };

    unsafe { CloseHandle(token_handle) };

    if result == 0 {
        log::error!(
            "Failed to enable SE_SHUTDOWN_NAME: {}",
            io::Error::last_os_error()
        );
        return Err(test_rpc::Error::Syscall);
    }

    Ok(())
}

#[cfg(unix)]
pub fn reboot() -> Result<(), test_rpc::Error> {
    log::debug!("Rebooting system");

    std::thread::spawn(|| {
        #[cfg(target_os = "linux")]
        let mut cmd = std::process::Command::new("/usr/sbin/shutdown");
        #[cfg(target_os = "macos")]
        let mut cmd = std::process::Command::new("/sbin/shutdown");
        cmd.args(["-r", "now"]);

        std::thread::sleep(std::time::Duration::from_secs(5));

        let _ = cmd.spawn().map_err(|error| {
            log::error!("Failed to spawn shutdown command: {error}");
            error
        });
    });

    Ok(())
}

#[cfg(target_os = "linux")]
pub async fn set_daemon_log_level(verbosity_level: Verbosity) -> Result<(), test_rpc::Error> {
    use tokio::io::AsyncWriteExt;
    log::debug!("Setting log level");

    let verbosity = match verbosity_level {
        Verbosity::Info => "",
        Verbosity::Debug => "-v",
        Verbosity::Trace => "-vv",
    };
    let systemd_service_file_content = format!(
        r#"[Service]
ExecStart=
ExecStart=/usr/bin/mullvad-daemon --disable-stdout-timestamps {verbosity}"#
    );

    let override_path = std::path::Path::new(SYSTEMD_OVERRIDE_FILE);
    if let Some(parent) = override_path.parent() {
        tokio::fs::create_dir_all(parent)
            .await
            .map_err(|e| test_rpc::Error::ServiceChange(e.to_string()))?;
    }

    let mut file = tokio::fs::OpenOptions::new()
        .create(true)
        .truncate(true)
        .write(true)
        .open(override_path)
        .await
        .map_err(|e| test_rpc::Error::ServiceChange(e.to_string()))?;

    file.write_all(systemd_service_file_content.as_bytes())
        .await
        .map_err(|e| test_rpc::Error::ServiceChange(e.to_string()))?;

    tokio::process::Command::new("systemctl")
        .args(["daemon-reload"])
        .status()
        .await
        .map_err(|e| test_rpc::Error::ServiceStart(e.to_string()))?;

    restart_app().await?;
    Ok(())
}

/// Restart the Mullvad VPN application.
///
/// This function waits for the app to successfully start again.
#[cfg(target_os = "linux")]
pub async fn restart_app() -> Result<(), test_rpc::Error> {
    tokio::process::Command::new("systemctl")
        .args(["restart", "mullvad-daemon"])
        .status()
        .await
        .map_err(|e| test_rpc::Error::ServiceStart(e.to_string()))?;
    wait_for_service_state(ServiceState::Running).await?;
    Ok(())
}

/// Stop the Mullvad VPN application.
///
/// This function waits for the app to successfully shut down.
#[cfg(target_os = "linux")]
pub async fn stop_app() -> Result<(), test_rpc::Error> {
    tokio::process::Command::new("systemctl")
        .args(["stop", "mullvad-daemon"])
        .status()
        .await
        .map_err(|e| test_rpc::Error::ServiceStop(e.to_string()))?;
    wait_for_service_state(ServiceState::Inactive).await?;

    Ok(())
}

/// Start the Mullvad VPN application.
///
/// This function waits for the app to successfully start again.
#[cfg(target_os = "linux")]
pub async fn start_app() -> Result<(), test_rpc::Error> {
    tokio::process::Command::new("systemctl")
        .args(["start", "mullvad-daemon"])
        .status()
        .await
        .map_err(|e| test_rpc::Error::ServiceStart(e.to_string()))?;
    wait_for_service_state(ServiceState::Running).await?;
    Ok(())
}

/// Restart the Mullvad VPN application.
///
/// This function waits for the app to successfully start again.
#[cfg(target_os = "windows")]
pub async fn restart_app() -> Result<(), test_rpc::Error> {
    stop_app().await?;
    start_app().await?;
    Ok(())
}

/// Stop the Mullvad VPN application.
///
/// This function waits for the app to successfully shut down.
#[cfg(target_os = "windows")]
pub async fn stop_app() -> Result<(), test_rpc::Error> {
    let _ = tokio::process::Command::new("net")
        .args(["stop", "mullvadvpn"])
        .status()
        .await
        .map_err(|e| test_rpc::Error::ServiceStop(e.to_string()))?;
    Ok(())
}

/// Start the Mullvad VPN application.
///
/// This function waits for the app to successfully start again.
#[cfg(target_os = "windows")]
pub async fn start_app() -> Result<(), test_rpc::Error> {
    let _ = tokio::process::Command::new("net")
        .args(["start", "mullvadvpn"])
        .status()
        .await
        .map_err(|e| test_rpc::Error::ServiceStart(e.to_string()))?;
    Ok(())
}

/// Restart the Mullvad VPN application.
///
/// This function waits for the app to successfully start again.
#[cfg(target_os = "macos")]
pub async fn restart_app() -> Result<(), test_rpc::Error> {
    stop_app().await?;
    start_app().await?;
    Ok(())
}

/// Stop the Mullvad VPN application.
///
/// This function waits for the app to successfully shut down.
#[cfg(target_os = "macos")]
pub async fn stop_app() -> Result<(), test_rpc::Error> {
    set_launch_daemon_state(false).await?;
    tokio::time::sleep(std::time::Duration::from_millis(1000)).await;
    Ok(())
}

/// Start the Mullvad VPN application.
///
/// This function waits for the app to successfully start again.
#[cfg(target_os = "macos")]
pub async fn start_app() -> Result<(), test_rpc::Error> {
    set_launch_daemon_state(true).await?;
    tokio::time::sleep(std::time::Duration::from_millis(1000)).await;
    Ok(())
}

#[cfg(target_os = "windows")]
pub async fn set_daemon_log_level(verbosity_level: Verbosity) -> Result<(), test_rpc::Error> {
    log::debug!("Setting log level");

    let verbosity = match verbosity_level {
        Verbosity::Info => "",
        Verbosity::Debug => "-v",
        Verbosity::Trace => "-vv",
    };

    let manager = ServiceManager::local_computer(None::<&str>, ServiceManagerAccess::CONNECT)
        .map_err(|e| test_rpc::Error::ServiceNotFound(e.to_string()))?;
    let service = manager
        .open_service(
            "mullvadvpn",
            ServiceAccess::QUERY_CONFIG
                | ServiceAccess::CHANGE_CONFIG
                | ServiceAccess::START
                | ServiceAccess::STOP,
        )
        .map_err(|e| test_rpc::Error::ServiceNotFound(e.to_string()))?;

    // Stop the service
    // TODO: Extract to separate function.
    service
        .stop()
        .map_err(|e| test_rpc::Error::ServiceStop(e.to_string()))?;
    tokio::process::Command::new("net")
        .args(["stop", "mullvadvpn"])
        .status()
        .await
        .map_err(|e| test_rpc::Error::ServiceStop(e.to_string()))?;

    // Get the current service configuration
    let config = service
        .query_config()
        .map_err(|e| test_rpc::Error::ServiceNotFound(e.to_string()))?;

    let executable_path = "C:\\Program Files\\Mullvad VPN\\resources\\mullvad-daemon.exe";
    let launch_arguments = vec![
        OsString::from("--run-as-service"),
        OsString::from(verbosity),
    ];

    // Update the service binary arguments
    let updated_config = ServiceInfo {
        name: config.display_name.clone(),
        display_name: config.display_name.clone(),
        service_type: config.service_type,
        start_type: config.start_type,
        error_control: config.error_control,
        executable_path: std::path::PathBuf::from(executable_path),
        launch_arguments,
        dependencies: config.dependencies.clone(),
        account_name: config.account_name.clone(),
        account_password: None,
    };

    // Apply the updated configuration
    service
        .change_config(&updated_config)
        .map_err(|e| test_rpc::Error::ServiceChange(e.to_string()))?;

    // Start the service
    // TODO: Extract to separate function.
    service
        .start::<String>(&[])
        .map_err(|e| test_rpc::Error::ServiceNotFound(e.to_string()))?;

    Ok(())
}

#[cfg(target_os = "macos")]
#[allow(clippy::unused_async)]
pub async fn set_daemon_log_level(_verbosity_level: Verbosity) -> Result<(), test_rpc::Error> {
    // TODO: Not implemented
    log::warn!("Setting log level is not implemented on macOS");
    Ok(())
}

#[cfg(target_os = "linux")]
#[derive(Debug)]
struct EnvVar {
    var: String,
    value: String,
}

#[cfg(target_os = "linux")]
impl EnvVar {
    fn from_systemd_string(s: &str) -> Result<Self, &'static str> {
        // Here, we are only concerned with parsing a line that starts with "Environment".
        let error = "Failed to parse systemd env-config";
        let mut input = s.trim().split('=');
        let pre = input.next().ok_or(error)?;
        match pre {
            "Environment" => {
                // Proccess the input just a bit more - remove the leading and trailing quote (").
                let var = input
                    .next()
                    .ok_or(error)?
                    .trim_start_matches('"')
                    .to_string();
                let value = input.next().ok_or(error)?.trim_end_matches('"').to_string();
                Ok(EnvVar { var, value })
            }
            _ => Err(error),
        }
    }

    fn to_systemd_string(&self) -> String {
        format!(
            "Environment=\"{key}={value}\"",
            key = self.var,
            value = self.value
        )
    }
}

#[cfg(target_os = "linux")]
pub async fn set_daemon_environment(env: HashMap<String, String>) -> Result<(), test_rpc::Error> {
    use std::{fmt::Write, ops::Not};

    let mut override_content = String::new();
    override_content.push_str("[Service]\n");

    for env_var in env
        .into_iter()
        .map(|(var, value)| EnvVar { var, value })
        .map(|env_var| env_var.to_systemd_string())
    {
        writeln!(&mut override_content, "{env_var}")
            .map_err(|err| test_rpc::Error::ServiceChange(err.to_string()))?;
    }

    let override_path = std::path::Path::new(SYSTEMD_OVERRIDE_FILE);
    if let Some(parent) = override_path.parent() {
        tokio::fs::create_dir_all(parent)
            .await
            .map_err(|e| test_rpc::Error::ServiceChange(e.to_string()))?;
    }

    tokio::fs::write(override_path, override_content)
        .await
        .map_err(|e| test_rpc::Error::ServiceChange(e.to_string()))?;

    if tokio::process::Command::new("systemctl")
        .args(["daemon-reload"])
        .status()
        .await
        .map_err(|e| test_rpc::Error::Io(e.to_string()))?
        .success()
        .not()
    {
        return Err(test_rpc::Error::ServiceChange(
            "Daemon service could not be reloaded".to_owned(),
        ));
    };

    if tokio::process::Command::new("systemctl")
        .args(["restart", "mullvad-daemon"])
        .status()
        .await
        .map_err(|e| test_rpc::Error::Io(e.to_string()))?
        .success()
        .not()
    {
        return Err(test_rpc::Error::ServiceStart(
            "Daemon service could not be restarted".to_owned(),
        ));
    };

    wait_for_service_state(ServiceState::Running).await?;
    Ok(())
}

#[cfg(target_os = "windows")]
pub async fn set_daemon_environment(env: HashMap<String, String>) -> Result<(), test_rpc::Error> {
    // Set environment globally (not for service) to prevent it from being lost on upgrade
    for (k, v) in env.clone() {
        tokio::process::Command::new("setx")
            .arg("/m")
            .args([k, v])
            .status()
            .await
            .map_err(|e| test_rpc::Error::Registry(e.to_string()))?;
    }
    // Persist the changed environment variables, such that we can retrieve them at will.
    use winreg::{enums::*, RegKey};
    let hklm = RegKey::predef(HKEY_LOCAL_MACHINE);
    let path = Path::new(MULLVAD_WIN_REGISTRY).join("Environment");
    let (registry, _) = hklm.create_subkey(&path).map_err(|error| {
        test_rpc::Error::Registry(format!("Failed to open Mullvad VPN subkey: {}", error))
    })?;
    for (k, v) in env {
        registry.set_value(k, &v).map_err(|error| {
            test_rpc::Error::Registry(format!("Failed to set Environment var: {}", error))
        })?;
    }

    // Restart service
    stop_app().await?;
    start_app().await?;

    Ok(())
}

#[cfg(target_os = "windows")]
pub fn get_system_path_var() -> Result<String, test_rpc::Error> {
    use winreg::{enums::*, *};

    let hklm = RegKey::predef(HKEY_LOCAL_MACHINE);
    let key = hklm
        .open_subkey("SYSTEM\\CurrentControlSet\\Control\\Session Manager\\Environment")
        .map_err(|error| {
            test_rpc::Error::Registry(format!("Failed to open Environment subkey: {}", error))
        })?;

    let path: String = key
        .get_value("Path")
        .map_err(|error| test_rpc::Error::Registry(format!("Failed to get PATH: {}", error)))?;

    Ok(path)
}

#[cfg(target_os = "macos")]
pub async fn set_daemon_environment(env: HashMap<String, String>) -> Result<(), test_rpc::Error> {
    tokio::task::spawn_blocking(|| {
        let mut parsed_plist = plist::Value::from_file(PLIST_OVERRIDE_FILE).map_err(|error| {
            test_rpc::Error::ServiceNotFound(format!("failed to parse plist: {error}"))
        })?;

        let mut vars = plist::Dictionary::new();
        for (k, v) in env {
            // Set environment globally (not for service) to prevent it from being lost on upgrade
            std::process::Command::new("launchctl")
                .arg("setenv")
                .args([&k, &v])
                .status()
                .map_err(|e| test_rpc::Error::ServiceChange(e.to_string()))?;
            vars.insert(k, plist::Value::String(v));
        }

        // Add permanent env var
        parsed_plist
            .as_dictionary_mut()
            .ok_or_else(|| test_rpc::Error::ServiceChange("plist missing dict".to_owned()))?
            .insert(
                "EnvironmentVariables".to_owned(),
                plist::Value::Dictionary(vars),
            );

        let daemon_plist = std::fs::File::create(PLIST_OVERRIDE_FILE)
            .map_err(|e| test_rpc::Error::ServiceChange(format!("failed to open plist: {e}")))?;

        parsed_plist
            .to_writer_xml(daemon_plist)
            .map_err(|e| test_rpc::Error::ServiceChange(format!("failed to replace plist: {e}")))?;

        Ok::<(), test_rpc::Error>(())
    })
    .await
    .unwrap()?;

    // Restart service
    set_launch_daemon_state(false).await?;
    tokio::time::sleep(std::time::Duration::from_millis(1000)).await;
    set_launch_daemon_state(true).await?;
    tokio::time::sleep(std::time::Duration::from_millis(1000)).await;
    Ok(())
}

#[cfg(target_os = "macos")]
async fn set_launch_daemon_state(on: bool) -> Result<(), test_rpc::Error> {
    let mut launchctl = tokio::process::Command::new("launchctl");
    if on {
        launchctl
            .args(["load", "-w", PLIST_OVERRIDE_FILE])
            .status()
            .await
            .map_err(|e| test_rpc::Error::ServiceStart(e.to_string()))?;
    } else {
        launchctl
            .args(["unload", "-w", PLIST_OVERRIDE_FILE])
            .status()
            .await
            .map_err(|e| test_rpc::Error::ServiceStop(e.to_string()))?;
    }
    Ok(())
}

#[cfg(target_os = "linux")]
pub async fn get_daemon_environment() -> Result<HashMap<String, String>, test_rpc::Error> {
    let text = tokio::fs::read_to_string(SYSTEMD_OVERRIDE_FILE)
        .await
        .map_err(|err| test_rpc::Error::FileSystem(err.to_string()))?;

    let env: HashMap<String, String> = parse_systemd_env_file(&text)
        .map(|EnvVar { var, value }| (var, value))
        .collect();
    Ok(env)
}

/// Parse a systemd env-file. `input` is assumed to be the entire text content of a systemd-env
/// file.
///
/// Example systemd-env file:
/// ```
/// [Service]
/// Environment="VAR1=pGNqduRFkB4K9C2vijOmUDa2kPtUhArN"
/// Environment="VAR2=JP8YLOc2bsNlrGuD6LVTq7L36obpjzxd"
/// ```
#[cfg(target_os = "linux")]
fn parse_systemd_env_file(input: &str) -> impl Iterator<Item = EnvVar> + '_ {
    input
        .lines()
        .map(EnvVar::from_systemd_string)
        .filter_map(|env_var| env_var.ok())
        .inspect(|env_var| log::trace!("Parsed {env_var:?}"))
}

#[cfg(target_os = "windows")]
pub async fn get_daemon_environment() -> Result<HashMap<String, String>, test_rpc::Error> {
    use winreg::{enums::*, RegKey};

    let env =
        tokio::task::spawn_blocking(|| -> Result<HashMap<String, String>, test_rpc::Error> {
            let hklm = RegKey::predef(HKEY_LOCAL_MACHINE);
            let key = hklm.open_subkey(MULLVAD_WIN_REGISTRY).map_err(|error| {
                test_rpc::Error::Registry(format!("Failed to open Mullvad VPN subkey: {}", error))
            })?;

            // The Strings will be quoted (surrounded by ") when read from the registry - we should
            // trim that!
            let trim = |string: String| string.trim_matches('"').to_owned();
            let env = key
                .open_subkey("Environment")
                .map_err(|error| {
                    test_rpc::Error::Registry(format!(
                        "Failed to open Environment subkey: {}",
                        error
                    ))
                })?
                .enum_values()
                .filter_map(|x| x.inspect_err(|err| log::trace!("{err}")).ok())
                .map(|(k, v)| (trim(k), trim(v.to_string())))
                .collect();
            Ok(env)
        })
        .await
        .map_err(test_rpc::Error::from_tokio_join_error)??;

    Ok(env)
}

#[cfg(target_os = "macos")]
pub async fn get_daemon_environment() -> Result<HashMap<String, String>, test_rpc::Error> {
    let plist = tokio::task::spawn_blocking(|| {
        let parsed_plist = plist::Value::from_file(PLIST_OVERRIDE_FILE).map_err(|error| {
            test_rpc::Error::ServiceNotFound(format!("failed to parse plist: {error}"))
        })?;

        Ok::<plist::Value, test_rpc::Error>(parsed_plist)
    })
    .await
    .map_err(test_rpc::Error::from_tokio_join_error)??;

    let plist_tree = plist
        .as_dictionary()
        .ok_or_else(|| test_rpc::Error::ServiceNotFound("plist missing dict".to_owned()))?;
    let Some(env_vars) = plist_tree.get("EnvironmentVariables") else {
        // `EnvironmentVariables` does not exist in plist file, so there are no env variables to
        // parse.
        return Ok(HashMap::new());
    };
    let env_vars = env_vars.as_dictionary().ok_or_else(|| {
        test_rpc::Error::ServiceNotFound("`EnvironmentVariables` is not a dict".to_owned())
    })?;

    let env = env_vars
        .clone()
        .into_iter()
        .filter_map(|(key, value)| Some((key, value.into_string()?)))
        .collect();

    Ok(env)
}

#[cfg(target_os = "linux")]
enum ServiceState {
    Running,
    Inactive,
}

#[cfg(target_os = "linux")]
async fn wait_for_service_state(awaited_state: ServiceState) -> Result<(), test_rpc::Error> {
    const RETRY_ATTEMPTS: usize = 10;
    let mut attempt = 0;
    loop {
        attempt += 1;
        if attempt > RETRY_ATTEMPTS {
            return Err(test_rpc::Error::ServiceStart(String::from(
                "Awaiting new service state timed out",
            )));
        }

        let output = tokio::process::Command::new("systemctl")
            .args(["status", "mullvad-daemon"])
            .output()
            .await
            .map_err(|e| test_rpc::Error::ServiceNotFound(e.to_string()))?
            .stdout;
        let output = String::from_utf8_lossy(&output);

        match awaited_state {
            ServiceState::Running => {
                if output.contains("active (running)") {
                    break;
                }
            }
            ServiceState::Inactive => {
                if output.contains("inactive (dead)") {
                    break;
                }
            }
        }

        tokio::time::sleep(std::time::Duration::from_millis(1000)).await;
    }
    Ok(())
}

#[cfg(target_os = "macos")]
pub fn get_os_version() -> Result<OsVersion, test_rpc::Error> {
    use test_rpc::meta::MacosVersion;

    let version = talpid_platform_metadata::MacosVersion::new()
        .inspect_err(|error| {
            log::error!("Failed to obtain OS version: {error}");
        })
        .map_err(|_| test_rpc::Error::Syscall)?;

    Ok(OsVersion::Macos(MacosVersion {
        major: version.major_version(),
    }))
}

#[cfg(target_os = "windows")]
pub fn get_os_version() -> Result<OsVersion, test_rpc::Error> {
    use test_rpc::meta::WindowsVersion;

    let version = talpid_platform_metadata::WindowsVersion::new()
        .inspect_err(|error| {
            log::error!("Failed to obtain OS version: {error}");
        })
        .map_err(|_| test_rpc::Error::Syscall)?;

    Ok(OsVersion::Windows(WindowsVersion {
        major: version.release_version().0,
    }))
}

#[cfg(target_os = "linux")]
pub fn get_os_version() -> Result<OsVersion, test_rpc::Error> {
    Ok(OsVersion::Linux)
}

#[cfg(test)]
mod test {

    #[cfg(target_os = "linux")]
    #[test]
    fn parse_systemd_environment_variables() {
        use super::parse_systemd_env_file;
        // Define an example systemd environment file
        let systemd_file = "
        [Service]
        Environment=\"var1=value1\"
        Environment=\"var2=value2\"
        ";

        // Parse the "file"
        let env_vars: Vec<_> = parse_systemd_env_file(systemd_file).collect();

        // Assert that the environment variables it defines are parsed as expected.
        assert_eq!(env_vars.len(), 2);
        let first = env_vars.first().unwrap();
        assert_eq!(first.var, "var1");
        assert_eq!(first.value, "value1");
        let second = env_vars.get(1).unwrap();
        assert_eq!(second.var, "var2");
        assert_eq!(second.value, "value2");
    }
}