use failure::*;

use crate::tools;
use crate::api::schema::*;
use crate::api::router::*;
use serde_json::{json, Value};

use std::sync::Arc;
use std::process::{Command, Stdio};

static SERVICE_NAME_LIST: [&str; 6] = [
    "proxmox-backup",
    "sshd",
    "syslog",
    "cron",
    "postfix",
    "systemd-timesyncd",
];

fn real_service_name(service: &str) -> &str {

    // since postfix package 3.1.0-3.1 the postfix unit is only here
    // to manage subinstances, of which the default is called "-".
    // This is where we look for the daemon status

    if service == "postfix" {
        "postfix@-"
    } else {
        service
    }
}

fn get_full_service_state(service: &str) -> Result<Value, Error> {

    let real_service_name = real_service_name(service);

    let mut child = Command::new("/bin/systemctl")
        .args(&["show", real_service_name])
        .stdout(Stdio::piped())
        .spawn()?;

    use std::io::{BufRead,BufReader};

    let mut result = json!({});

    if let Some(ref mut stdout) = child.stdout {
        for line in BufReader::new(stdout).lines() {
            match line {
                Ok(line) => {
                    let mut iter = line.splitn(2, '=');
                    let key = iter.next();
                    let value = iter.next();
                    if let (Some(key), Some(value)) = (key, value) {
                        result[key] = Value::from(value);
                    }
                }
                Err(err) => {
                    log::error!("reading service config failed: {}", err);
                    let _ = child.kill();
                    break;
                }
            }
        }
    }

    let status = child.wait().unwrap();
    if !status.success() {
        bail!("systemctl show failed with {}", status);
    }

    Ok(result)
}

fn json_service_state(service: &str, status: Value) -> Value {

    if let Some(desc) = status["Description"].as_str() {
        let name = status["Name"].as_str().unwrap_or(service);
        let state = status["SubState"].as_str().unwrap_or("unknown");
        return json!({
            "service": service,
            "name": name,
            "desc": desc,
            "state": state,
        });
    }

    Value::Null
}


fn list_services(
    _param: Value,
    _info: &ApiMethod,
    _rpcenv: &mut RpcEnvironment,
) -> Result<Value, Error> {

    let mut list = vec![];

    for service in &SERVICE_NAME_LIST {
        match get_full_service_state(service) {
            Ok(status) => {
                let state = json_service_state(service, status);
                if state != Value::Null {
                    list.push(state);
                }
            }
            Err(err) => log::error!("{}", err),
        }
    }

    Ok(Value::from(list))
}

fn get_service_state(
    param: Value,
    _info: &ApiMethod,
    _rpcenv: &mut RpcEnvironment,
) -> Result<Value, Error> {

    let service = tools::required_string_param(&param, "service")?;

    if !SERVICE_NAME_LIST.contains(&service) {
        bail!("unknown service name '{}'", service);
    }

    let status = get_full_service_state(service)?;

    Ok(json_service_state(service, status))
}

fn run_service_command(service: &str, cmd: &str) -> Result<Value, Error> {

    // fixme: run background worker (fork_worker) ???

    match cmd {
        "start"|"stop"|"restart"|"reload" => {},
        _ => bail!("unknown service command '{}'", cmd),
    }

    if service == "proxmox-backup" {
        if cmd != "restart" {
	    bail!("invalid service cmd '{} {}'", service, cmd);
        }
    }

    let real_service_name = real_service_name(service);

    let status = Command::new("/bin/systemctl")
        .args(&[cmd, real_service_name])
        .status()?;

    if !status.success() {
        bail!("systemctl {} failed with {}", cmd, status);
    }

    Ok(Value::Null)
}

fn start_service(
    param: Value,
    _info: &ApiMethod,
    _rpcenv: &mut RpcEnvironment,
) -> Result<Value, Error> {

    let service = tools::required_string_param(&param, "service")?;

    log::info!("starting service {}", service);

    run_service_command(service, "start")
}

fn stop_service(
    param: Value,
    _info: &ApiMethod,
    _rpcenv: &mut RpcEnvironment,
) -> Result<Value, Error> {

    let service = tools::required_string_param(&param, "service")?;

    log::info!("stoping service {}", service);

    run_service_command(service, "stop")
}

fn restart_service(
    param: Value,
    _info: &ApiMethod,
    _rpcenv: &mut RpcEnvironment,
) -> Result<Value, Error> {

    let service = tools::required_string_param(&param, "service")?;

    log::info!("re-starting service {}", service);

    run_service_command(service, "restart")
}

fn reload_service(
    param: Value,
    _info: &ApiMethod,
    _rpcenv: &mut RpcEnvironment,
) -> Result<Value, Error> {

    let service = tools::required_string_param(&param, "service")?;

    log::info!("reloading service {}", service);

    run_service_command(service, "reload")
}

pub fn router() -> Router {

    let service_id_schema : Arc<Schema> = Arc::new(
        StringSchema::new("Service ID.")
            .max_length(256)
            .into()
    );

    let service_api = Router::new()
        .get(ApiMethod::new(
            |_,_,_| {
                let mut result = vec![];
                for cmd in &["state", "start", "stop", "restart", "reload"] {
                    result.push(json!({"subdir": cmd }));
                }
                Ok(Value::from(result))
            },
            ObjectSchema::new("Directory index.")
                .required("service", service_id_schema.clone()))
        )
        .subdir(
            "state",
            Router::new()
                .get(ApiMethod::new(
                    get_service_state,
                    ObjectSchema::new("Read service properties.")
                        .required("service", service_id_schema.clone()))
                )
        )
        .subdir(
            "start",
            Router::new()
                .post(
                    ApiMethod::new(
                        start_service,
                        ObjectSchema::new("Start service.")
                            .required("service", service_id_schema.clone())
                    ).protected(true)
                )
        )
        .subdir(
            "stop",
            Router::new()
                .post(
                    ApiMethod::new(
                        stop_service,
                        ObjectSchema::new("Stop service.")
                            .required("service", service_id_schema.clone())
                    ).protected(true)
                )
        )
        .subdir(
            "restart",
            Router::new()
                .post(
                    ApiMethod::new(
                        restart_service,
                        ObjectSchema::new("Restart service.")
                            .required("service", service_id_schema.clone())
                    ).protected(true)
                )
        )
        .subdir(
            "reload",
            Router::new()
                .post(
                    ApiMethod::new(
                        reload_service,
                        ObjectSchema::new("Reload service.")
                            .required("service", service_id_schema.clone())
                    ).protected(true)
                )
        )
        ;

    let route = Router::new()
        .get(
            ApiMethod::new(
                list_services,
                ObjectSchema::new("Service list.")
            ).returns(
                ArraySchema::new(
                    "Returns a list of systemd services.",
                    ObjectSchema::new("Service details.")
                        .required("service", service_id_schema.clone())
                        .required("name", StringSchema::new("systemd service name."))
                        .required("desc", StringSchema::new("systemd service description."))
                        .required("state", StringSchema::new("systemd service 'SubState'."))
                        .into()
                )
            )
        )
        .match_all("service", service_api);

    route
}