backbone-bucket 0.3.0

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

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

/// States for Bucket workflow
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Serialize, Deserialize)]
#[serde(rename_all = "snake_case")]
pub enum BucketState {
    /// Initial state
    Active,
    Readonly,
    Archived,
    /// Final state
    Deleted,
}

impl Default for BucketState {
    fn default() -> Self {
        Self::Active
    }
}

impl std::fmt::Display for BucketState {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            Self::Active => write!(f, "active"),
            Self::Readonly => write!(f, "readonly"),
            Self::Archived => write!(f, "archived"),
            Self::Deleted => write!(f, "deleted"),
        }
    }
}

impl FromStr for BucketState {
    type Err = StateMachineError;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        match s.to_lowercase().as_str() {
            "active" => Ok(Self::Active),
            "readonly" => Ok(Self::Readonly),
            "archived" => Ok(Self::Archived),
            "deleted" => Ok(Self::Deleted),
            _ => Err(StateMachineError::InvalidState(s.to_string())),
        }
    }
}

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

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

    /// Get all possible states
    pub fn all() -> Vec<Self> {
        vec![
            Self::Active,
            Self::Readonly,
            Self::Archived,
            Self::Deleted,
        ]
    }
}

/// Transitions for Bucket workflow
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Serialize, Deserialize)]
#[serde(rename_all = "snake_case")]
pub enum BucketTransition {
    /// active -> readonly
    Lock,
    /// readonly -> active
    Unlock,
    /// active, readonly -> archived
    Archive,
    /// archived -> active
    Restore,
    /// active, readonly, archived -> deleted
    Delete,
}

impl std::fmt::Display for BucketTransition {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            Self::Lock => write!(f, "lock"),
            Self::Unlock => write!(f, "unlock"),
            Self::Archive => write!(f, "archive"),
            Self::Restore => write!(f, "restore"),
            Self::Delete => write!(f, "delete"),
        }
    }
}

impl FromStr for BucketTransition {
    type Err = StateMachineError;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        match s.to_lowercase().as_str() {
            "lock" => Ok(Self::Lock),
            "unlock" => Ok(Self::Unlock),
            "archive" => Ok(Self::Archive),
            "restore" => Ok(Self::Restore),
            "delete" => Ok(Self::Delete),
            _ => Err(StateMachineError::InvalidTransition(s.to_string())),
        }
    }
}

impl BucketTransition {
    /// Get the target state of this transition
    pub fn target_state(&self) -> BucketState {
        match self {
            Self::Lock => BucketState::Readonly,
            Self::Unlock => BucketState::Active,
            Self::Archive => BucketState::Archived,
            Self::Restore => BucketState::Active,
            Self::Delete => BucketState::Deleted,
        }
    }

    /// Get all transitions
    pub fn all() -> Vec<Self> {
        vec![
            Self::Lock,
            Self::Unlock,
            Self::Archive,
            Self::Restore,
            Self::Delete,
        ]
    }

    /// Get allowed roles for this transition
    pub fn allowed_roles(&self) -> &'static [&'static str] {
        match self {
            Self::Lock => &["admin", "owner"],
            Self::Unlock => &["admin", "owner"],
            Self::Archive => &["admin", "owner"],
            Self::Restore => &["admin", "owner"],
            Self::Delete => &["admin", "owner"],
        }
    }
}

use super::StateMachineError;

/// State machine for Bucket workflow
#[derive(Debug, Clone)]
pub struct BucketStateMachine {
    current_state: BucketState,
}

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

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

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

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

        match (self.current_state, transition) {
            (BucketState::Active, BucketTransition::Lock) => true,
            (BucketState::Readonly, BucketTransition::Unlock) => true,
            (BucketState::Active, BucketTransition::Archive) => true,
            (BucketState::Readonly, BucketTransition::Archive) => true,
            (BucketState::Archived, BucketTransition::Restore) => true,
            (BucketState::Active, BucketTransition::Delete) => true,
            (BucketState::Readonly, BucketTransition::Delete) => true,
            (BucketState::Archived, BucketTransition::Delete) => true,
            _ => false,
        }
    }

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

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

    #[test]
    fn test_initial_state() {
        let sm = BucketStateMachine::new();
        assert_eq!(sm.current_state(), BucketState::Active);
        assert!(sm.current_state().is_initial());
    }

    #[test]
    fn test_valid_transition() {
        let mut sm = BucketStateMachine::from_state(BucketState::Active);
        assert!(sm.can_transition(BucketTransition::Lock));
        let result = sm.transition(BucketTransition::Lock);
        assert!(result.is_ok());
        assert_eq!(sm.current_state(), BucketState::Readonly);
    }

    #[test]
    fn test_invalid_transition() {
        let mut sm = BucketStateMachine::from_state(BucketState::Active);
        // Unlock is not valid from Active state
        let result = sm.transition(BucketTransition::Unlock);
        assert!(result.is_err());
    }

    #[test]
    fn test_state_parsing() {
        let state: BucketState = "active".parse().unwrap();
        assert_eq!(state, BucketState::Active);
    }

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