use std::ops::{Deref, Index, IndexMut};

use graph::Graph;
use super::Frozen;
use graph::{IndexType, GraphIndex};
use {
    Direction,
    EdgeType,
};
use visit::{Data, IntoNodeIdentifiers, GraphProp, NodeIndexable, IntoNeighborsDirected};
use visit::{IntoNeighbors, IntoNodeReferences, IntoEdgeReferences, Visitable};
use visit::{NodeCompactIndexable, GetAdjacencyMatrix, NodeCount, IntoEdges, IntoEdgesDirected};
use data::{DataMap, DataMapMut};


impl<'a, G> Frozen<'a, G> {
    /// Create a new `Frozen` from a mutable reference to a graph.
    pub fn new(gr: &'a mut G) -> Self {
        Frozen(gr)
    }
}

/// Deref allows transparent access to all shared reference (read-only)
/// functionality in the underlying graph.
impl<'a, G> Deref for Frozen<'a, G> {
    type Target = G;
    fn deref(&self) -> &G { self.0 }
}

impl<'a, G, I> Index<I> for Frozen<'a, G>
    where G: Index<I>
{
    type Output = G::Output;
    fn index(&self, i: I) -> &G::Output { self.0.index(i) }
}

impl<'a, G, I> IndexMut<I> for Frozen<'a, G>
    where G: IndexMut<I>
{
    fn index_mut(&mut self, i: I) -> &mut G::Output { self.0.index_mut(i) }
}

impl<'a, N, E, Ty, Ix> Frozen<'a, Graph<N, E, Ty, Ix>>
    where Ty: EdgeType,
          Ix: IndexType,
{
    /// Index the `Graph` by two indices, any combination of
    /// node or edge indices is fine.
    ///
    /// **Panics** if the indices are equal or if they are out of bounds.
    pub fn index_twice_mut<T, U>(&mut self, i: T, j: U)
        -> (&mut <Graph<N, E, Ty, Ix> as Index<T>>::Output,
            &mut <Graph<N, E, Ty, Ix> as Index<U>>::Output)
        where Graph<N, E, Ty, Ix>: IndexMut<T> + IndexMut<U>,
              T: GraphIndex,
              U: GraphIndex,
    {
        self.0.index_twice_mut(i, j)
    }
}

macro_rules! access0 {
    ($e:expr) => ($e.0);
}

Data!{delegate_impl [['a, G], G, Frozen<'a, G>, deref_twice]}
DataMap!{delegate_impl [['a, G], G, Frozen<'a, G>, deref_twice]}
DataMapMut!{delegate_impl [['a, G], G, Frozen<'a, G>, access0]}
GetAdjacencyMatrix!{delegate_impl [['a, G], G, Frozen<'a, G>, deref_twice]}
IntoEdgeReferences!{delegate_impl [['a, 'b, G], G, &'b Frozen<'a, G>, deref_twice]}
IntoEdges!{delegate_impl [['a, 'b, G], G, &'b Frozen<'a, G>, deref_twice]}
IntoEdgesDirected!{delegate_impl [['a, 'b, G], G, &'b Frozen<'a, G>, deref_twice]}
IntoNeighbors!{delegate_impl [['a, 'b, G], G, &'b Frozen<'a, G>, deref_twice]}
IntoNeighborsDirected!{delegate_impl [['a, 'b, G], G, &'b Frozen<'a, G>, deref_twice]}
IntoNodeIdentifiers!{delegate_impl [['a, 'b, G], G, &'b Frozen<'a, G>, deref_twice]}
IntoNodeReferences!{delegate_impl [['a, 'b, G], G, &'b Frozen<'a, G>, deref_twice]}
NodeCompactIndexable!{delegate_impl [['a, G], G, Frozen<'a, G>, deref_twice]}
NodeCount!{delegate_impl [['a, G], G, Frozen<'a, G>, deref_twice]}
NodeIndexable!{delegate_impl [['a, G], G, Frozen<'a, G>, deref_twice]}
GraphProp!{delegate_impl [['a, G], G, Frozen<'a, G>, deref_twice]}
Visitable!{delegate_impl [['a, G], G, Frozen<'a, G>, deref_twice]}