backbone-mail 0.2.32

//! State machine for MailHooks workflow
//!
//! Generated by metaphor-schema

use serde::{Deserialize, Serialize};
use std::str::FromStr;

/// States for MailHooks workflow
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Serialize, Deserialize)]
#[serde(rename_all = "snake_case")]
pub enum MailHooksState {
    /// Initial state
    Outgoing,
    /// Final state
    Sent,
    /// Final state
    Received,
    Exception,
    /// Final state
    Cancel,
}

impl Default for MailHooksState {
    fn default() -> Self {
        Self::Outgoing
    }
}

impl std::fmt::Display for MailHooksState {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            Self::Outgoing => write!(f, "outgoing"),
            Self::Sent => write!(f, "sent"),
            Self::Received => write!(f, "received"),
            Self::Exception => write!(f, "exception"),
            Self::Cancel => write!(f, "cancel"),
        }
    }
}

impl FromStr for MailHooksState {
    type Err = StateMachineError;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        match s.to_lowercase().as_str() {
            "outgoing" => Ok(Self::Outgoing),
            "sent" => Ok(Self::Sent),
            "received" => Ok(Self::Received),
            "exception" => Ok(Self::Exception),
            "cancel" => Ok(Self::Cancel),
            _ => Err(StateMachineError::InvalidState(s.to_string())),
        }
    }
}

impl MailHooksState {
    /// Check if this is the initial state
    pub fn is_initial(&self) -> bool {
        matches!(self, Self::Outgoing)
    }

    /// Check if this is a final state
    pub fn is_final(&self) -> bool {
        matches!(self, Self::Sent | Self::Received | Self::Cancel)
    }

    /// Get all possible states
    pub fn all() -> Vec<Self> {
        vec![
            Self::Outgoing,
            Self::Sent,
            Self::Received,
            Self::Exception,
            Self::Cancel,
        ]
    }
}

/// Transitions for MailHooks workflow
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Serialize, Deserialize)]
#[serde(rename_all = "snake_case")]
pub enum MailHooksTransition {
    /// outgoing -> sent
    SmtpAccepted,
    /// outgoing -> exception
    SmtpFailed,
    /// sent -> received
    InboundAcknowledged,
    /// exception -> outgoing
    Requeued,
    /// outgoing, exception -> cancel
    Cancelled,
}

impl std::fmt::Display for MailHooksTransition {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            Self::SmtpAccepted => write!(f, "smtp_accepted"),
            Self::SmtpFailed => write!(f, "smtp_failed"),
            Self::InboundAcknowledged => write!(f, "inbound_acknowledged"),
            Self::Requeued => write!(f, "requeued"),
            Self::Cancelled => write!(f, "cancelled"),
        }
    }
}

impl FromStr for MailHooksTransition {
    type Err = StateMachineError;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        match s.to_lowercase().as_str() {
            "smtp_accepted" => Ok(Self::SmtpAccepted),
            "smtp_failed" => Ok(Self::SmtpFailed),
            "inbound_acknowledged" => Ok(Self::InboundAcknowledged),
            "requeued" => Ok(Self::Requeued),
            "cancelled" => Ok(Self::Cancelled),
            _ => Err(StateMachineError::InvalidTransition(s.to_string())),
        }
    }
}

impl MailHooksTransition {
    /// Get the target state of this transition
    pub fn target_state(&self) -> MailHooksState {
        match self {
            Self::SmtpAccepted => MailHooksState::Sent,
            Self::SmtpFailed => MailHooksState::Exception,
            Self::InboundAcknowledged => MailHooksState::Received,
            Self::Requeued => MailHooksState::Outgoing,
            Self::Cancelled => MailHooksState::Cancel,
        }
    }

    /// Get all transitions
    pub fn all() -> Vec<Self> {
        vec![
            Self::SmtpAccepted,
            Self::SmtpFailed,
            Self::InboundAcknowledged,
            Self::Requeued,
            Self::Cancelled,
        ]
    }

    /// Get allowed roles for this transition
    pub fn allowed_roles(&self) -> &'static [&'static str] {
        match self {
            Self::SmtpAccepted => &[],
            Self::SmtpFailed => &[],
            Self::InboundAcknowledged => &[],
            Self::Requeued => &[],
            Self::Cancelled => &[],
        }
    }
}

use super::StateMachineError;

/// State machine for MailHooks workflow
#[derive(Debug, Clone)]
pub struct MailHooksStateMachine {
    current_state: MailHooksState,
}

impl MailHooksStateMachine {
    /// Create a new state machine with initial state
    pub fn new() -> Self {
        Self {
            current_state: MailHooksState::default(),
        }
    }

    /// Create from an existing state
    pub fn from_state(state: MailHooksState) -> Self {
        Self { current_state: state }
    }

    /// Get the current state
    pub fn current_state(&self) -> MailHooksState {
        self.current_state
    }

    /// Check if a transition is allowed from the current state
    pub fn can_transition(&self, transition: MailHooksTransition) -> bool {
        if matches!(self.current_state, MailHooksState::Received | MailHooksState::Cancel) {
            return false;
        }

        match (self.current_state, transition) {
            (MailHooksState::Outgoing, MailHooksTransition::SmtpAccepted) => true,
            (MailHooksState::Outgoing, MailHooksTransition::SmtpFailed) => true,
            (MailHooksState::Sent, MailHooksTransition::InboundAcknowledged) => true,
            (MailHooksState::Exception, MailHooksTransition::Requeued) => true,
            (MailHooksState::Outgoing, MailHooksTransition::Cancelled) => true,
            (MailHooksState::Exception, MailHooksTransition::Cancelled) => true,
            _ => false,
        }
    }

    /// Check if a transition is allowed for a given role
    pub fn can_transition_with_role(&self, transition: MailHooksTransition, role: &str) -> bool {
        if !self.can_transition(transition) {
            return false;
        }

        let allowed_roles = transition.allowed_roles();
        if allowed_roles.is_empty() {
            return true; // No role restriction
        }

        allowed_roles.iter().any(|r| *r == role || *r == "*")
    }

    /// Apply a transition, returning the new state
    pub fn transition(&mut self, transition: MailHooksTransition) -> Result<MailHooksState, StateMachineError> {
        if !self.can_transition(transition) {
            return Err(StateMachineError::TransitionNotAllowed {
                transition: transition.to_string(),
                from: self.current_state.to_string(),
            });
        }

        self.current_state = transition.target_state();
        Ok(self.current_state)
    }

    /// Apply a transition with role check
    pub fn transition_with_role(&mut self, transition: MailHooksTransition, role: &str) -> Result<MailHooksState, StateMachineError> {
        // Check basic transition validity first
        if !self.can_transition(transition) {
            return Err(StateMachineError::TransitionNotAllowed {
                transition: transition.to_string(),
                from: self.current_state.to_string(),
            });
        }

        // Check role authorization
        if !self.can_transition_with_role(transition, role) {
            return Err(StateMachineError::RoleNotAuthorized {
                role: role.to_string(),
                transition: transition.to_string(),
            });
        }

        self.current_state = transition.target_state();
        Ok(self.current_state)
    }

    /// Get all available transitions from the current state
    pub fn available_transitions(&self) -> Vec<MailHooksTransition> {
        MailHooksTransition::all()
            .into_iter()
            .filter(|t| self.can_transition(*t))
            .collect()
    }

    /// Get all available transitions for a given role
    pub fn available_transitions_for_role(&self, role: &str) -> Vec<MailHooksTransition> {
        MailHooksTransition::all()
            .into_iter()
            .filter(|t| self.can_transition_with_role(*t, role))
            .collect()
    }

    /// Attempt to transition directly to a target state.
    ///
    /// Finds any transition that leads to the target state and applies it.
    /// Returns Err if no valid transition leads from current state to target.
    pub fn transition_to_state(&mut self, target: MailHooksState) -> Result<MailHooksState, StateMachineError> {
        let valid = MailHooksTransition::all().into_iter()
            .filter(|t| self.can_transition(*t))
            .find(|t| t.target_state() == target);
        match valid {
            Some(t) => self.transition(t),
            None => Err(StateMachineError::TransitionNotAllowed {
                transition: target.to_string(),
                from: self.current_state.to_string(),
            }),
        }
    }
}

impl Default for MailHooksStateMachine {
    fn default() -> Self {
        Self::new()
    }
}

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

    #[test]
    fn test_initial_state() {
        let sm = MailHooksStateMachine::new();
        assert_eq!(sm.current_state(), MailHooksState::Outgoing);
        assert!(sm.current_state().is_initial());
    }

    #[test]
    fn test_valid_transition() {
        let mut sm = MailHooksStateMachine::from_state(MailHooksState::Outgoing);
        assert!(sm.can_transition(MailHooksTransition::SmtpAccepted));
        let result = sm.transition(MailHooksTransition::SmtpAccepted);
        assert!(result.is_ok());
        assert_eq!(sm.current_state(), MailHooksState::Sent);
    }

    #[test]
    fn test_invalid_transition() {
        let mut sm = MailHooksStateMachine::from_state(MailHooksState::Outgoing);
        // InboundAcknowledged is not valid from Outgoing state
        let result = sm.transition(MailHooksTransition::InboundAcknowledged);
        assert!(result.is_err());
    }

    #[test]
    fn test_state_parsing() {
        let state: MailHooksState = "outgoing".parse().unwrap();
        assert_eq!(state, MailHooksState::Outgoing);
    }

    #[test]
    fn test_available_transitions() {
        let sm = MailHooksStateMachine::new();
        let available = sm.available_transitions();
        // Should have at least some transitions available from initial state
        assert!(!available.is_empty() || sm.current_state().is_final());
    }
}