regent-sdk 0.8.1

//! Cron job management attribute
//!
//! This module provides the `CronBlockExpectedState` type for managing cron jobs
//! on Unix-like systems, supporting both user crontabs and system cron.d files.
//!
//! # Examples
//!
//! ## Rust API
//!
//! ```no_run
//! use regent_sdk::state::attribute::system::cron::{CronBlockExpectedState, CronExpectedState, CronSpecialTime};
//! use regent_sdk::{Attribute, ExpectedState, Privilege};
//!
//! // Schedule a daily backup job
//! let backup = CronBlockExpectedState::builder("backup")
//!     .with_job("/usr/local/bin/backup.sh")
//!     .with_special_time(CronSpecialTime::Daily)
//!     .build()
//!     .unwrap();
//!
//! let expected_state = ExpectedState::new()
//!     .with_attribute(Attribute::cron(backup, Privilege::WithSudo, None))
//!     .build();
//! ```
//!
//! ## YAML API
//!
//! ```yaml
//! Attributes:
//!   - Detail: !Cron
//!       Name: backup
//!       Job: /usr/local/bin/backup.sh
//!       SpecialTime: !Daily
//!       Privilege: !WithSudo
//! ```

use crate::error::RegentError;
use crate::hosts::managed_host::InternalApiCallOutcome;
use crate::hosts::managed_host::{AssessCompliance, ReachCompliance, Timeout};
use crate::hosts::properties::HostProperties;
use crate::secrets::SecretProvidersPool;
use crate::state::Check;
use crate::state::attribute::HostHandler;
use crate::state::attribute::Privilege;
use crate::state::attribute::Remediation;
use crate::state::compliance::AttributeComplianceAssessment;
use serde::{Deserialize, Serialize};
use std::time::Duration;

const REGENT_MARKER_PREFIX: &str = "# regent: ";

/// Desired state of a cron job
#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
#[serde(rename_all = "PascalCase")]
pub enum CronExpectedState {
    /// Cron job should exist
    Present,
    /// Cron job should not exist
    Absent,
}

/// Special time strings for cron schedules
///
/// These are shortcuts for common scheduling patterns like @daily, @weekly, etc.
#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
#[serde(rename_all = "PascalCase")]
pub enum CronSpecialTime {
    /// Run at boot time
    Reboot,
    /// Run once a year at midnight on Jan 1
    Yearly,
    /// Run once a year at midnight on Jan 1 (alias for Yearly)
    Annually,
    /// Run once a month at midnight on the first day
    Monthly,
    /// Run once a week at midnight on Sunday
    Weekly,
    /// Run once a day at midnight
    Daily,
    /// Run once an hour at the beginning of the hour
    Hourly,
}

impl std::fmt::Display for CronSpecialTime {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        let s = match self {
            CronSpecialTime::Reboot => "reboot",
            CronSpecialTime::Yearly => "yearly",
            CronSpecialTime::Annually => "annually",
            CronSpecialTime::Monthly => "monthly",
            CronSpecialTime::Weekly => "weekly",
            CronSpecialTime::Daily => "daily",
            CronSpecialTime::Hourly => "hourly",
        };
        write!(f, "{}", s)
    }
}

/// Configuration for a cron job
///
/// Use the builder pattern to create cron jobs with various scheduling options.
/// Each cron job must have a unique name and a job command when state is Present.
/// You can specify timing using either individual time fields (minute, hour, day, month, weekday)
/// or special_time shortcuts like Daily, Weekly, etc.
///
/// For system-wide cron jobs, use cron_file to specify a file in /etc/cron.d/.
/// For user-specific jobs, use user to specify the username.
#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
#[serde(deny_unknown_fields)]
#[serde(rename_all = "PascalCase")]
pub struct CronBlockExpectedState {
    /// Unique identifier for this cron job (used in marker comment)
    name: String,
    /// Desired state of the cron job (defaults to Present if not specified)
    state: Option<CronExpectedState>,
    /// Command to execute
    job: Option<String>,
    /// Minute field (0-59, or * for any)
    minute: Option<String>,
    /// Hour field (0-23, or * for any)
    hour: Option<String>,
    /// Day of month field (1-31, or * for any)
    day: Option<String>,
    /// Month field (1-12, or * for any)
    month: Option<String>,
    /// Weekday field (0-6, where 0 is Sunday, or * for any)
    weekday: Option<String>,
    /// User to run the cron job as (for user crontabs)
    user: Option<String>,
    /// Specific cron.d file to use (for system cron jobs)
    cron_file: Option<String>,
    /// Special time shortcut (replaces minute, hour, day, month, weekday)
    special_time: Option<CronSpecialTime>,
    /// Whether this cron job is disabled (commented out)
    disabled: Option<bool>,
}

impl Timeout for CronBlockExpectedState {
    fn default_timeout(&self) -> Duration {
        Duration::from_secs(5)
    }
}

impl CronBlockExpectedState {
    pub fn builder(name: &str) -> CronBlockExpectedState {
        CronBlockExpectedState {
            name: name.to_string(),
            state: None,
            job: None,
            minute: None,
            hour: None,
            day: None,
            month: None,
            weekday: None,
            user: None,
            cron_file: None,
            special_time: None,
            disabled: None,
        }
    }

    pub fn with_state(&mut self, state: CronExpectedState) -> &mut Self {
        self.state = Some(state);
        self
    }

    pub fn with_job(&mut self, job: &str) -> &mut Self {
        self.job = Some(job.to_string());
        self
    }

    pub fn with_minute(&mut self, minute: &str) -> &mut Self {
        self.minute = Some(minute.to_string());
        self
    }

    pub fn with_hour(&mut self, hour: &str) -> &mut Self {
        self.hour = Some(hour.to_string());
        self
    }

    pub fn with_day(&mut self, day: &str) -> &mut Self {
        self.day = Some(day.to_string());
        self
    }

    pub fn with_month(&mut self, month: &str) -> &mut Self {
        self.month = Some(month.to_string());
        self
    }

    pub fn with_weekday(&mut self, weekday: &str) -> &mut Self {
        self.weekday = Some(weekday.to_string());
        self
    }

    pub fn with_user(&mut self, user: &str) -> &mut Self {
        self.user = Some(user.to_string());
        self
    }

    pub fn with_cron_file(&mut self, cron_file: &str) -> &mut Self {
        self.cron_file = Some(cron_file.to_string());
        self
    }

    pub fn with_special_time(&mut self, special_time: CronSpecialTime) -> &mut Self {
        self.special_time = Some(special_time);
        self
    }

    pub fn with_disabled(&mut self, disabled: bool) -> &mut Self {
        self.disabled = Some(disabled);
        self
    }

    pub fn build(&self) -> Result<CronBlockExpectedState, RegentError> {
        self.check()?;
        Ok(self.clone())
    }
}

impl Check for CronBlockExpectedState {
    fn check(&self) -> Result<(), RegentError> {
        let state = self.state.as_ref().unwrap_or(&CronExpectedState::Present);
        if let CronExpectedState::Present = state {
            if self.job.is_none() {
                return Err(RegentError::IncoherentExpectedState(
                    "Job is required when state is Present.".to_string(),
                ));
            }
        }
        if self.special_time.is_some() {
            let has_time_fields = self.minute.is_some()
                || self.hour.is_some()
                || self.day.is_some()
                || self.month.is_some()
                || self.weekday.is_some();
            if has_time_fields {
                return Err(RegentError::IncoherentExpectedState(
                    "Minute, Hour, Day, Month, Weekday are incompatible with SpecialTime."
                        .to_string(),
                ));
            }
        }
        Ok(())
    }
}

impl<Handler: HostHandler> AssessCompliance<Handler> for CronBlockExpectedState {
    async fn assess_compliance(
        &self,
        host_handler: &mut Handler,
        _host_properties: &Option<HostProperties>,
        privilege: &Privilege,
        _optional_secret_provider: &Option<SecretProvidersPool>,
    ) -> Result<AttributeComplianceAssessment, RegentError> {
        let expected_state = self.state.as_ref().unwrap_or(&CronExpectedState::Present);
        let is_cron_d = self.cron_file.is_some();

        if !is_cron_d
            && !host_handler
                .is_this_command_available("crontab", privilege)
                .await
                .unwrap()
        {
            return Err(RegentError::FailedDryRunEvaluation(
                "crontab not available on this host".to_string(),
            ));
        }

        let content = match get_cron_content(host_handler, &self.user, &self.cron_file).await {
            Ok(c) => c,
            Err(e) => return Err(RegentError::FailedDryRunEvaluation(e)),
        };

        let existing_entry = find_cron_entry(&content, &self.name);

        match expected_state {
            CronExpectedState::Absent => {
                if existing_entry.is_none() {
                    return Ok(AttributeComplianceAssessment::Compliant);
                }
                Ok(AttributeComplianceAssessment::NonCompliant(vec![
                    Remediation::Cron(CronApiCall::from(
                        CronModuleInternalApiCall::Remove {
                            name: self.name.clone(),
                            user: self.user.clone(),
                            cron_file: self.cron_file.clone(),
                        },
                        privilege.clone(),
                    )),
                ]))
            }
            CronExpectedState::Present => {
                let expected_line = build_cron_line(self, is_cron_d);
                let needs_upsert = match existing_entry {
                    None => true,
                    Some(ref current) => current != &expected_line,
                };

                if needs_upsert {
                    return Ok(AttributeComplianceAssessment::NonCompliant(vec![
                        Remediation::Cron(CronApiCall::from(
                            CronModuleInternalApiCall::Upsert {
                                name: self.name.clone(),
                                cron_line: expected_line,
                                user: self.user.clone(),
                                cron_file: self.cron_file.clone(),
                            },
                            privilege.clone(),
                        )),
                    ]));
                }

                Ok(AttributeComplianceAssessment::Compliant)
            }
        }
    }
}

#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
#[serde(rename_all = "PascalCase")]
pub enum CronModuleInternalApiCall {
    // Creates or updates a named cron entry (identified by its regent marker comment)
    Upsert {
        name: String,
        cron_line: String,
        user: Option<String>,
        cron_file: Option<String>,
    },
    Remove {
        name: String,
        user: Option<String>,
        cron_file: Option<String>,
    },
}

impl std::fmt::Display for CronModuleInternalApiCall {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            CronModuleInternalApiCall::Upsert { name, .. } => {
                write!(f, "upsert cron entry '{}'", name)
            }
            CronModuleInternalApiCall::Remove { name, .. } => {
                write!(f, "remove cron entry '{}'", name)
            }
        }
    }
}

#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
pub struct CronApiCall {
    pub api_call: CronModuleInternalApiCall,
    privilege: Privilege,
}

impl CronApiCall {
    pub fn display(&self) -> String {
        match &self.api_call {
            CronModuleInternalApiCall::Upsert { name, .. } => {
                format!("Upsert cron entry '{}'", name)
            }
            CronModuleInternalApiCall::Remove { name, .. } => {
                format!("Remove cron entry '{}'", name)
            }
        }
    }

    fn from(api_call: CronModuleInternalApiCall, privilege: Privilege) -> CronApiCall {
        CronApiCall {
            api_call,
            privilege,
        }
    }
}

impl<Handler: HostHandler> ReachCompliance<Handler> for CronApiCall {
    async fn call(
        &self,
        host_handler: &mut Handler,
        _host_properties: &Option<HostProperties>,
        _optional_secret_provider: &Option<SecretProvidersPool>,
    ) -> Result<InternalApiCallOutcome, RegentError> {
        let (cmd, privilege) = match &self.api_call {
            CronModuleInternalApiCall::Upsert {
                name,
                cron_line,
                user,
                cron_file,
            } => {
                let cmd = if let Some(file) = cron_file {
                    // /etc/cron.d/ approach: remove existing entry (if any) then append
                    format!(
                        "touch /etc/cron.d/{f} && sed -i '/^# regent: {n}$/{{N;d;}}' /etc/cron.d/{f} && printf '# regent: {n}\\n{l}\\n' >> /etc/cron.d/{f}",
                        f = file,
                        n = name,
                        l = cron_line
                    )
                } else {
                    // User crontab approach: rebuild crontab minus old entry, then append new one
                    let uf = user_flag(user);
                    format!(
                        "(crontab -l {uf}2>/dev/null | sed '/^# regent: {n}$/{{N;d;}}'; printf '# regent: {n}\\n{l}\\n') | crontab {uf}-",
                        uf = uf,
                        n = name,
                        l = cron_line
                    )
                };
                (cmd, &self.privilege)
            }
            CronModuleInternalApiCall::Remove {
                name,
                user,
                cron_file,
            } => {
                let cmd = if let Some(file) = cron_file {
                    format!(
                        "sed -i '/^# regent: {n}$/{{N;d;}}' /etc/cron.d/{f}",
                        n = name,
                        f = file
                    )
                } else {
                    let uf = user_flag(user);
                    format!(
                        "crontab -l {uf}2>/dev/null | sed '/^# regent: {n}$/{{N;d;}}' | crontab {uf}-",
                        uf = uf,
                        n = name
                    )
                };
                (cmd, &self.privilege)
            }
        };

        let cmd_result = host_handler
            .run_command(cmd.as_str(), privilege)
            .await
            .unwrap();

        if cmd_result.return_code == 0 {
            Ok(InternalApiCallOutcome::Success(None))
        } else {
            Ok(InternalApiCallOutcome::Failure(format!(
                "RC: {}, STDOUT: {}, STDERR: {}",
                cmd_result.return_code, cmd_result.stdout, cmd_result.stderr
            )))
        }
    }
}

fn user_flag(user: &Option<String>) -> String {
    match user {
        Some(u) => format!("-u {} ", u),
        None => String::new(),
    }
}

async fn get_cron_content<Handler: HostHandler>(
    host_handler: &mut Handler,
    user: &Option<String>,
    cron_file: &Option<String>,
) -> Result<String, String> {
    if let Some(file) = cron_file {
        let result = host_handler
            .run_command(&format!("cat /etc/cron.d/{}", file), &Privilege::None)
            .await
            .map_err(|e| format!("Failed to read cron file: {:?}", e))?;
        Ok(if result.return_code == 0 {
            result.stdout
        } else {
            String::new()
        })
    } else {
        let cmd = match user {
            Some(u) => format!("crontab -l -u {}", u),
            None => "crontab -l".to_string(),
        };
        let result = host_handler
            .run_command(&cmd, &Privilege::None)
            .await
            .map_err(|e| format!("Failed to read crontab: {:?}", e))?;
        // rc=1 means "no crontab for user" — treat as empty
        Ok(if result.return_code == 0 {
            result.stdout
        } else {
            String::new()
        })
    }
}

fn find_cron_entry(content: &str, name: &str) -> Option<String> {
    let marker = format!("{}{}", REGENT_MARKER_PREFIX, name);
    let mut lines = content.lines();
    while let Some(line) = lines.next() {
        if line == marker {
            return lines.next().map(|l| l.to_string());
        }
    }
    None
}

fn build_cron_line(block: &CronBlockExpectedState, is_cron_d: bool) -> String {
    let timing = if let Some(ref st) = block.special_time {
        format!("@{}", st)
    } else {
        format!(
            "{} {} {} {} {}",
            block.minute.as_deref().unwrap_or("*"),
            block.hour.as_deref().unwrap_or("*"),
            block.day.as_deref().unwrap_or("*"),
            block.month.as_deref().unwrap_or("*"),
            block.weekday.as_deref().unwrap_or("*"),
        )
    };

    let job = block.job.as_deref().unwrap_or("");

    let body = if is_cron_d {
        // /etc/cron.d/ entries require an explicit username field
        format!(
            "{} {} {}",
            timing,
            block.user.as_deref().unwrap_or("root"),
            job
        )
    } else {
        format!("{} {}", timing, job)
    };

    if block.disabled.unwrap_or(false) {
        format!("# {}", body)
    } else {
        body
    }
}

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

    #[test]
    fn parsing_cron_module_block_from_yaml_str() {
        let raw_attributes = "---
- Name: backup
  Job: /usr/local/bin/backup.sh
  Minute: '0'
  Hour: '2'

- Name: cleanup
  State: !Present
  Job: /usr/local/bin/cleanup.sh
  SpecialTime: !Daily

- Name: oldtask
  State: !Absent
        ";

        let _attributes: Vec<CronBlockExpectedState> =
            yaml_serde::from_str(raw_attributes).unwrap();
    }

    #[test]
    fn check_rejects_present_without_job() {
        let result = CronBlockExpectedState::builder("test")
            .with_state(CronExpectedState::Present)
            .build();
        assert!(result.is_err());
    }

    #[test]
    fn check_rejects_special_time_with_time_fields() {
        let result = CronBlockExpectedState::builder("test")
            .with_job("/bin/true")
            .with_special_time(CronSpecialTime::Daily)
            .with_minute("0")
            .build();
        assert!(result.is_err());
    }

    #[test]
    fn check_accepts_absent_without_job() {
        let result = CronBlockExpectedState::builder("test")
            .with_state(CronExpectedState::Absent)
            .build();
        assert!(result.is_ok());
    }

    #[test]
    fn build_cron_line_standard() {
        let block = CronBlockExpectedState::builder("test")
            .with_job("/usr/bin/backup.sh")
            .with_minute("0")
            .with_hour("2")
            .build()
            .unwrap();
        assert_eq!(
            build_cron_line(&block, false),
            "0 2 * * * /usr/bin/backup.sh"
        );
    }

    #[test]
    fn build_cron_line_special_time() {
        let block = CronBlockExpectedState::builder("test")
            .with_job("/usr/bin/backup.sh")
            .with_special_time(CronSpecialTime::Daily)
            .build()
            .unwrap();
        assert_eq!(build_cron_line(&block, false), "@daily /usr/bin/backup.sh");
    }

    #[test]
    fn build_cron_line_cron_d_with_user() {
        let block = CronBlockExpectedState::builder("test")
            .with_job("/usr/bin/backup.sh")
            .with_minute("30")
            .with_hour("3")
            .with_user("backup")
            .build()
            .unwrap();
        assert_eq!(
            build_cron_line(&block, true),
            "30 3 * * * backup /usr/bin/backup.sh"
        );
    }

    #[test]
    fn build_cron_line_disabled() {
        let block = CronBlockExpectedState::builder("test")
            .with_job("/usr/bin/backup.sh")
            .with_minute("0")
            .with_hour("1")
            .with_disabled(true)
            .build()
            .unwrap();
        assert_eq!(
            build_cron_line(&block, false),
            "# 0 1 * * * /usr/bin/backup.sh"
        );
    }

    #[test]
    fn find_cron_entry_found() {
        let content = "# regent: backup\n0 2 * * * /usr/local/bin/backup.sh\n";
        assert_eq!(
            find_cron_entry(content, "backup"),
            Some("0 2 * * * /usr/local/bin/backup.sh".to_string())
        );
    }

    #[test]
    fn find_cron_entry_not_found() {
        let content = "# regent: other\n0 2 * * * /usr/local/bin/other.sh\n";
        assert!(find_cron_entry(content, "backup").is_none());
    }
}