#include <iostream>
#include <cmath>

#include "IMeshEdge.hxx"
#include "IMeshPoint.hxx"

COMET::IMeshEdge::IMeshEdge(COMET::IMeshPoint* a, COMET::IMeshPoint* b) {
    if (*a < *b) {
        fHead = a;
        fTail = b;
    }
    else {
        fHead = b;
        fTail = a;
    }
    // The edge is not added into the two end points by the constructor.  It
    // will be added to the points by COMET::IMesh::AddEdge, iff they don't already
    // exist.
}

COMET::IMeshEdge::~IMeshEdge() {
    // Remove the edge from the end points so that we don't have any dangling
    // pointers.  Notice that this makes deleting a COMET::IMesh object rather
    // interesting since a COMET::IMeshPoint will delete it's associated edges when
    // it is deleted.
    if (fHead) fHead->RemoveEdge(this);
    if (fTail) fTail->RemoveEdge(this);
}

COMET::IMeshPoint* COMET::IMeshEdge::GetOther(const COMET::IMeshPoint* a) const {
    if (a == fHead) return fTail;
    if (a == fTail) return fHead;
    return NULL;
}

double COMET::IMeshEdge::GetLength(void) const {
    return GetLength(1.0,1.0);
}

double COMET::IMeshEdge::GetLength(double xScale, double yScale) const {
    return std::sqrt(std::pow(xScale*(GetTail()->X() - GetHead()->X()),2)
                     + std::pow(yScale*(GetTail()->Y() - GetHead()->Y()),2));
}

bool COMET::IMeshEdge::operator == (const COMET::IMeshEdge& rhs) const {
    if (fHead != rhs.GetHead()) return false;
    if (fTail != rhs.GetTail()) return false;
    return true;
}

bool COMET::IMeshEdge::operator < (const COMET::IMeshEdge& rhs) const {
    if (*fHead < *rhs.fHead) return true;
    if (*rhs.fHead < *fHead) return false;
    if (*fTail < *rhs.fTail) return true;
    return false;
}

std::ostream& operator << (std::ostream& s, COMET::IMeshEdge& e) {
    s << &e << "->(" << e.GetHead() << ", " << e.GetTail() << ")";
    return s;
}