// lightsys.cpp - TRAFFIC LIGHT SYSTEM SIMULATOR
//
// MODULE INDEX
// NAME                 CONTENTS
// ColourStr            Colour string
// Display              Set traffic light colours
// main                 Main line
//
// MAINTENANCE HISTORY
// DATE         PROGRAMMER AND DETAILS
// 09-11-02     JS      Original
//
//-----------------------------------------------------------------------------

#include <stdio.h>              // Standard input/output
#include <string.h>             // String manipulation
#include <stdlib.h>             // Standard library
#include <errno.h>              // Error codes
#include "lightsys.h"           // Traffic light system declarations

//-----------------------------------------------------------------------------

// GLOBAL DATA

static Colour   northState;     // Current traffic light states
static Colour   eastState;
static Colour   southState;
static Colour   westState;
static int      tickCnt;        // Tick count
static int      northWait;      // Vehicle waiting flags
static int      eastWait;
static int      southWait;
static int      westWait;

//-----------------------------------------------------------------------------

// COLOUR STRING

char *
ColourStr (
        Colour          colour)         // Colour to convert to string
{
        char            *str;           // String value

        switch (colour) {
        case RED:       str = "R";              break;
        case AMBER:     str = "A";              break;
        case GREEN:     str = "G";              break;
        default:        str = "?";              break;
        }
        return str;
}

//-----------------------------------------------------------------------------

// SET TRAFFIC LIGHT COLOURS

void
Display (
        Colour          northColour,    // New traffic light settings
        Colour          eastColour,
        Colour          southColour,
        Colour          westColour)
{
        printf ("%3d\n%d %d %d %d  %s %s %s %s ",
                tickCnt,
                northWait,
                eastWait,
                southWait,
                westWait,
                ColourStr(northColour),
                ColourStr(eastColour),
                ColourStr(southColour),
                ColourStr(westColour)
        );
        tickCnt = 0;

        northState = northColour;
        eastState = eastColour;
        southState = southColour;
        westState = westColour;
}

//-----------------------------------------------------------------------------

// MAIN LINE

int
main ()
{
        int             northNewWait;   // Vehicle waiting flags
        int             eastNewWait;
        int             southNewWait;
        int             westNewWait;

        northWait = 0;
        eastWait = 0;
        southWait = 0;
        westWait = 0;

        srand48 (2031960);

        InitApp ();
        for (;;) {

                // Set the new waiting states

                northNewWait = northWait;
                eastNewWait = eastWait;
                southNewWait = southWait;
                westNewWait = westWait;
                if (northState == GREEN || northState == AMBER)
                        northNewWait = 0;
                else if (lrand48() % 120 == 7)
                        northNewWait = 1;
                if (eastState == GREEN || eastState == AMBER)
                        eastNewWait = 0;
                else if (lrand48() % 120 == 7)
                        eastNewWait = 1;
                if (southState == GREEN || southState == AMBER)
                        southNewWait = 0;
                else if (lrand48() % 120 == 7)
                        southNewWait = 1;
                if (westState == GREEN || westState == AMBER)
                        westNewWait = 0;
                else if (lrand48() % 120 == 7)
                        westNewWait = 1;

                // If the waiting states have changed, notify the
                // application.

                if (
                        northNewWait != northWait ||
                        eastNewWait != eastWait ||
                        southNewWait != southWait ||
                        westNewWait != westWait
                ) {
                        northWait = northNewWait;
                        eastWait = eastNewWait;
                        southWait = southNewWait;
                        westWait = westNewWait;
                        VehicleWaiting (northWait, eastWait,
                                southWait, westWait);
                }

                // Increment the tick count

                tickCnt ++ ;

                // Process a clock tick

                Tick ();
        }
        return 0;
}