backbone-bucket 0.3.0

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

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

/// States for ConversionJob workflow
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Serialize, Deserialize)]
#[serde(rename_all = "snake_case")]
pub enum ConversionJobState {
    /// Initial state
    Pending,
    Processing,
    /// Final state
    Completed,
    /// Final state
    Failed,
    /// Final state
    Cancelled,
}

impl Default for ConversionJobState {
    fn default() -> Self {
        Self::Pending
    }
}

impl std::fmt::Display for ConversionJobState {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            Self::Pending => write!(f, "pending"),
            Self::Processing => write!(f, "processing"),
            Self::Completed => write!(f, "completed"),
            Self::Failed => write!(f, "failed"),
            Self::Cancelled => write!(f, "cancelled"),
        }
    }
}

impl FromStr for ConversionJobState {
    type Err = StateMachineError;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        match s.to_lowercase().as_str() {
            "pending" => Ok(Self::Pending),
            "processing" => Ok(Self::Processing),
            "completed" => Ok(Self::Completed),
            "failed" => Ok(Self::Failed),
            "cancelled" => Ok(Self::Cancelled),
            _ => Err(StateMachineError::InvalidState(s.to_string())),
        }
    }
}

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

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

    /// Get all possible states
    pub fn all() -> Vec<Self> {
        vec![
            Self::Pending,
            Self::Processing,
            Self::Completed,
            Self::Failed,
            Self::Cancelled,
        ]
    }
}

/// Transitions for ConversionJob workflow
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Serialize, Deserialize)]
#[serde(rename_all = "snake_case")]
pub enum ConversionJobTransition {
    /// pending -> processing
    Start,
    /// processing -> processing
    UpdateProgress,
    /// processing -> completed
    Complete,
    /// processing -> failed
    Fail,
    /// pending -> cancelled
    CancelPending,
    /// processing -> cancelled
    CancelRunning,
    /// failed -> pending
    Retry,
    /// completed -> pending
    Reconvert,
}

impl std::fmt::Display for ConversionJobTransition {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            Self::Start => write!(f, "start"),
            Self::UpdateProgress => write!(f, "update_progress"),
            Self::Complete => write!(f, "complete"),
            Self::Fail => write!(f, "fail"),
            Self::CancelPending => write!(f, "cancel_pending"),
            Self::CancelRunning => write!(f, "cancel_running"),
            Self::Retry => write!(f, "retry"),
            Self::Reconvert => write!(f, "reconvert"),
        }
    }
}

impl FromStr for ConversionJobTransition {
    type Err = StateMachineError;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        match s.to_lowercase().as_str() {
            "start" => Ok(Self::Start),
            "update_progress" => Ok(Self::UpdateProgress),
            "complete" => Ok(Self::Complete),
            "fail" => Ok(Self::Fail),
            "cancel_pending" => Ok(Self::CancelPending),
            "cancel_running" => Ok(Self::CancelRunning),
            "retry" => Ok(Self::Retry),
            "reconvert" => Ok(Self::Reconvert),
            _ => Err(StateMachineError::InvalidTransition(s.to_string())),
        }
    }
}

impl ConversionJobTransition {
    /// Get the target state of this transition
    pub fn target_state(&self) -> ConversionJobState {
        match self {
            Self::Start => ConversionJobState::Processing,
            Self::UpdateProgress => ConversionJobState::Processing,
            Self::Complete => ConversionJobState::Completed,
            Self::Fail => ConversionJobState::Failed,
            Self::CancelPending => ConversionJobState::Cancelled,
            Self::CancelRunning => ConversionJobState::Cancelled,
            Self::Retry => ConversionJobState::Pending,
            Self::Reconvert => ConversionJobState::Pending,
        }
    }

    /// Get all transitions
    pub fn all() -> Vec<Self> {
        vec![
            Self::Start,
            Self::UpdateProgress,
            Self::Complete,
            Self::Fail,
            Self::CancelPending,
            Self::CancelRunning,
            Self::Retry,
            Self::Reconvert,
        ]
    }

    /// Get allowed roles for this transition
    pub fn allowed_roles(&self) -> &'static [&'static str] {
        match self {
            Self::Start => &["system"],
            Self::UpdateProgress => &["system"],
            Self::Complete => &["system"],
            Self::Fail => &["system"],
            Self::CancelPending => &["owner", "admin"],
            Self::CancelRunning => &["owner", "admin"],
            Self::Retry => &["system", "owner"],
            Self::Reconvert => &["owner", "admin"],
        }
    }
}

use super::StateMachineError;

/// State machine for ConversionJob workflow
#[derive(Debug, Clone)]
pub struct ConversionJobStateMachine {
    current_state: ConversionJobState,
}

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

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

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

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

        match (self.current_state, transition) {
            (ConversionJobState::Pending, ConversionJobTransition::Start) => true,
            (ConversionJobState::Processing, ConversionJobTransition::UpdateProgress) => true,
            (ConversionJobState::Processing, ConversionJobTransition::Complete) => true,
            (ConversionJobState::Processing, ConversionJobTransition::Fail) => true,
            (ConversionJobState::Pending, ConversionJobTransition::CancelPending) => true,
            (ConversionJobState::Processing, ConversionJobTransition::CancelRunning) => true,
            (ConversionJobState::Failed, ConversionJobTransition::Retry) => true,
            (ConversionJobState::Completed, ConversionJobTransition::Reconvert) => true,
            _ => false,
        }
    }

    /// Check if a transition is allowed for a given role
    pub fn can_transition_with_role(&self, transition: ConversionJobTransition, 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: ConversionJobTransition) -> Result<ConversionJobState, 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: ConversionJobTransition, role: &str) -> Result<ConversionJobState, 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<ConversionJobTransition> {
        ConversionJobTransition::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<ConversionJobTransition> {
        ConversionJobTransition::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: ConversionJobState) -> Result<ConversionJobState, StateMachineError> {
        let valid = ConversionJobTransition::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 ConversionJobStateMachine {
    fn default() -> Self {
        Self::new()
    }
}

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

    #[test]
    fn test_initial_state() {
        let sm = ConversionJobStateMachine::new();
        assert_eq!(sm.current_state(), ConversionJobState::Pending);
        assert!(sm.current_state().is_initial());
    }

    #[test]
    fn test_valid_transition() {
        let mut sm = ConversionJobStateMachine::from_state(ConversionJobState::Pending);
        assert!(sm.can_transition(ConversionJobTransition::Start));
        let result = sm.transition(ConversionJobTransition::Start);
        assert!(result.is_ok());
        assert_eq!(sm.current_state(), ConversionJobState::Processing);
    }

    #[test]
    fn test_invalid_transition() {
        let mut sm = ConversionJobStateMachine::from_state(ConversionJobState::Pending);
        // UpdateProgress is not valid from Pending state
        let result = sm.transition(ConversionJobTransition::UpdateProgress);
        assert!(result.is_err());
    }

    #[test]
    fn test_state_parsing() {
        let state: ConversionJobState = "pending".parse().unwrap();
        assert_eq!(state, ConversionJobState::Pending);
    }

    #[test]
    fn test_available_transitions() {
        let sm = ConversionJobStateMachine::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());
    }
}