// File: BaselineGraph.h
//
// CMSC 341 Spring 2019
//
// Header file for Baseline::Graph class
//

#ifndef _BASELINEGRAPH_H_
#define _BASELINEGRAPH_H_

#include <stdexcept>  // For throwing out_of_range exceptions
#include <tuple>      // Edges are represented as tuple<int,int,int>
#include <vector>     // m_nz, m_ci, and m_re are of type vector<int>

class Grader;  // Forward declaration needed for 'friend'

namespace Baseline {
  
  class Graph {

  public:

    friend Grader;   // Allows Grader class to access private variables
    
    // Graph constructor; must give number of vertices
    Graph(int n);

    // return number of vertices
    int numVert();

    // return number of edges
    int numEdge();

    // add edge between u and v with weight x
    void addEdge(int u, int v, int x);

    // print out data structure for debugging
    void dump();

    // Edge Iterator inner class
    class EgIterator {

    public: 
      // Edge Iterator constructor; indx can be used to
      // set m_indx for begin and end iterators.
      EgIterator(Graph *Gptr = nullptr, int indx = 0);

      // Compare iterators; only makes sense to compare with
      // end iterator
      bool operator!= (const EgIterator& rhs);
	 
      // Move iterator to next printable edge
      void operator++(int dummy);   // post increment

      // return edge at iterator location
      std::tuple<int,int,int> operator*();

    private:
      Graph *m_Gptr;    // pointer to associated Graph
      int m_indx;       // index of current edge in m_nz
      int m_row;        // corresponding row of m_nz[m_indx]
    };

    // Make an initial edge Iterator
    EgIterator egBegin();

    // Make an end iterator for edge iterator
    EgIterator egEnd();

    // Neighbor Iterator inner class
    class NbIterator {
    
    public: 
      // Constructor for iterator for vertices adjacent to vertex v;
      // indx can be used to set m_indx for begin and end iterators
      NbIterator(Graph *Gptr = nullptr, int v = 0, int indx = 0);

      // Compare iterators; only makes sense to compare with
      // end iterator
      bool operator!=(const NbIterator& rhs);

      // Move iterator to next neighbor
      void operator++(int dummy);

      // Return neighbor at current iterator position
      int operator*();

    private:
      Graph *m_Gptr;  // pointer to the associated Graph
      int m_row;      // row (source) for which to find neighbors
      int m_indx;     // current index into m_nz of Graph
    };

    // Make an initial neighbor iterator
    NbIterator nbBegin(int v);

    // Make an end neighbor iterator
    NbIterator nbEnd(int v);

  private:
    std::vector<int> m_nz;  // non-zero elements array
    std::vector<int> m_ci;  // column index array
    std::vector<int> m_re;  // row extent array
    
    int m_numVert;  // number of vertices
    int m_numEdge;  // number of edges
  };
}

#endif