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use arc::Arc;
use fst_traits::{CoreFst, ExpandedFst};
use std::collections::HashMap;
use Result;
use StateId;
/// Trait defining the methods to modify a wFST
pub trait MutableFst: CoreFst + for<'a> MutableArcIterator<'a> {
/// Creates an empty wFST
fn new() -> Self;
/// The state with identifier `state_id` is now the start state.
/// Note that only one start state is allowed in this implementation. Calling this function twice
/// will mean losing the first start state.
/// If the `state_id` doesn't exist an error is raised.
///
/// ```
/// use rustfst::fst_traits::{CoreFst, MutableFst, ExpandedFst};
/// use rustfst::fst_impls::VectorFst;
/// use rustfst::semirings::{BooleanWeight, Semiring};
/// use rustfst::arc::Arc;
///
/// let mut fst = VectorFst::<BooleanWeight>::new();
/// let s1 = fst.add_state();
/// let s2 = fst.add_state();
///
/// assert_eq!(fst.start(), None);
///
/// fst.set_start(&s1);
/// assert_eq!(fst.start(), Some(s1));
///
/// fst.set_start(&s2);
/// assert_eq!(fst.start(), Some(s2));
/// ```
fn set_start(&mut self, state_id: &StateId) -> Result<()>;
/// The state with identifier `state_id` is now a final state with a weight `final_weight`.
/// If the `state_id` doesn't exist an error is raised.
///
/// ```
/// use rustfst::fst_traits::{CoreFst, MutableFst, ExpandedFst};
/// use rustfst::fst_impls::VectorFst;
/// use rustfst::semirings::{BooleanWeight, Semiring};
/// use rustfst::arc::Arc;
///
/// let mut fst = VectorFst::<BooleanWeight>::new();
/// let s1 = fst.add_state();
/// let s2 = fst.add_state();
///
/// assert_eq!(fst.final_weight(&s1), None);
/// assert_eq!(fst.final_weight(&s2), None);
///
/// fst.set_final(&s1, BooleanWeight::one());
/// assert_eq!(fst.final_weight(&s1), Some(BooleanWeight::one()));
/// assert_eq!(fst.final_weight(&s2), None);
///
/// fst.set_final(&s2, BooleanWeight::one());
/// assert_eq!(fst.final_weight(&s1), Some(BooleanWeight::one()));
/// assert_eq!(fst.final_weight(&s2), Some(BooleanWeight::one()));
/// ```
fn set_final(&mut self, state_id: &StateId, final_weight: <Self as CoreFst>::W) -> Result<()>;
/// Adds a new state to the current FST. The identifier of the new state is returned
///
/// # Example
///
/// ```
/// use rustfst::fst_traits::{CoreFst, MutableFst, ExpandedFst};
/// use rustfst::fst_impls::VectorFst;
/// use rustfst::semirings::{BooleanWeight, Semiring};
///
/// let mut fst = VectorFst::<BooleanWeight>::new();
///
/// assert_eq!(fst.num_states(), 0);
///
/// fst.add_state();
/// assert_eq!(fst.num_states(), 1);
///
/// fst.add_state();
/// assert_eq!(fst.num_states(), 2);
///
/// ```
fn add_state(&mut self) -> StateId;
/// Removes a state from an FST. It also removes all the arcs starting from another state and
/// reaching this state. An error is raised if the state `state_id` doesn't exist.
///
/// # Example
///
/// ```
/// use rustfst::fst_traits::{CoreFst, MutableFst, ExpandedFst, StateIterator};
/// use rustfst::fst_impls::VectorFst;
/// use rustfst::semirings::{BooleanWeight, Semiring};
///
/// let mut fst = VectorFst::<BooleanWeight>::new();
///
/// assert_eq!(fst.states_iter().count(), 0);
///
/// let s1 = fst.add_state();
///
/// assert_eq!(fst.states_iter().count(), 1);
///
/// fst.del_state(&s1);
///
/// assert_eq!(fst.states_iter().count(), 0);
///
/// ```
fn del_state(&mut self, state_id: &StateId) -> Result<()>;
/// Removes multiple states from an FST. If one of the states doesn't exist, an error is raised.
///
/// # Warning
///
/// This method modifies the id of the states that are left in the FST. Id that were used before
/// calling this function should no longer be used.
///
/// # Example
///
/// ```
/// use rustfst::fst_traits::{CoreFst, MutableFst, ExpandedFst, StateIterator};
/// use rustfst::fst_impls::VectorFst;
/// use rustfst::semirings::{BooleanWeight, Semiring};
///
/// let mut fst = VectorFst::<BooleanWeight>::new();
///
/// assert_eq!(fst.states_iter().count(), 0);
///
/// let s1 = fst.add_state();
/// let s2 = fst.add_state();
///
/// assert_eq!(fst.states_iter().count(), 2);
///
/// let states_to_remove = vec![s1, s2];
/// fst.del_states(states_to_remove.into_iter());
///
/// assert_eq!(fst.states_iter().count(), 0);
///
/// ```
fn del_states<T: IntoIterator<Item = StateId>>(&mut self, states: T) -> Result<()>;
/// Adds an arc to the FST. The arc will start in the state `source`.
/// An error is raised if the state `source` doesn't exist.
///
/// # Warning
///
/// This method modifies the id of the states that are left in the FST. Id that were used before
/// calling this function should no longer be used.
///
/// # Example
///
/// ```
/// use rustfst::fst_traits::{CoreFst, MutableFst, ExpandedFst};
/// use rustfst::fst_impls::VectorFst;
/// use rustfst::semirings::{BooleanWeight, Semiring};
/// use rustfst::arc::Arc;
///
/// let mut fst = VectorFst::<BooleanWeight>::new();
/// let s1 = fst.add_state();
/// let s2 = fst.add_state();
///
/// assert_eq!(fst.num_arcs(), 0);
/// fst.add_arc(&s1, Arc::new(3, 5, BooleanWeight::new(true), s2));
/// assert_eq!(fst.num_arcs(), 1);
/// ```
fn add_arc(&mut self, source: &StateId, arc: Arc<<Self as CoreFst>::W>) -> Result<()>;
// fn set_isyms<T: IntoIterator<Item=String>>(&mut self, symtab: T);
// fn set_osyms<T: IntoIterator<Item=String>>(&mut self, symtab: T);
fn add_fst<F: ExpandedFst<W = Self::W>>(
&mut self,
fst_to_add: &F,
) -> Result<HashMap<StateId, StateId>> {
// Map old states id to new ones
let mut mapping_states = HashMap::new();
// First pass to add the necessary states
for old_state_id in fst_to_add.states_iter() {
let new_state_id = self.add_state();
mapping_states.insert(old_state_id, new_state_id);
}
// Second pass to add the arcs
for old_state_id in fst_to_add.states_iter() {
for old_arc in fst_to_add.arcs_iter(&old_state_id)? {
self.add_arc(
&mapping_states[&old_state_id],
Arc::new(
old_arc.ilabel,
old_arc.olabel,
old_arc.weight.clone(),
mapping_states[&old_arc.nextstate],
),
)?;
}
}
Ok(mapping_states)
}
}
pub trait MutableArcIterator<'a>: CoreFst
where
Self::W: 'a,
{
type IterMut: Iterator<Item = &'a mut Arc<Self::W>>;
fn arcs_iter_mut(&'a mut self, &StateId) -> Result<Self::IterMut>;
}