// DIDN'T DO IN LECTURE, BUT PRETTY COOL IF YOU WANT TO EXAMINE
// THE CODE AND/OR GIVE IT A TRY! Of particplar interest is the
// graphCities method.

// Tyler Rigsby, CSE 142
// Plots cities with population greater than or equal to
// a value specified by the user

import java.awt.*; // For Graphics
import java.io.*; // For File, FileNotFoundException
import java.util.*; // For Scanner

public class Cities {
    // The width and height of the overall DrawingPanel
    public static final int WIDTH = 800;
    public static final int HEIGHT = 515;
    // The thickness of the gray border
    public static final int BORDER = 100;
    
    // The minimum and maximum latitude and longitude.
    // I wrote code to find these in the input file rather than
    // manually checking.
    public static final int MIN_LAT = 24562841;
    public static final int MAX_LAT = 48996136;
    public static final int MIN_LON = -124610967;
    public static final int MAX_LON = -67012040;

    public static void main(String[] args) throws FileNotFoundException {
        Scanner console = new Scanner(System.in);
        Scanner cityScan = new Scanner(new File("cities.txt"));

        printIntro();
        
        System.out.print("Plot all cities with population at least: ");
        int minPop = console.nextInt();
        
        DrawingPanel panel = new DrawingPanel(WIDTH, HEIGHT);
        Graphics g = panel.getGraphics();

        int cities = graphCities(g, cityScan, minPop);

        graphStatic(g, minPop, cities);
    }
    
    // Plots the cities with population greater than or equal to
    // minPop and returns the number of cities plotted.
    public static int graphCities(Graphics g, Scanner cityScan, int minPop) {
        int count = 0;
        while (cityScan.hasNextLine()) {
            String line = cityScan.nextLine();
            Scanner lineScan = new Scanner(line);
            String city = lineScan.next();
            String state = lineScan.next();
            int pop = lineScan.nextInt();
            if (pop >= minPop) {
                int lat = lineScan.nextInt();
                int lon = lineScan.nextInt();
                
                plotCity(g, lat, lon);
                count++;
            }
        }
        return count;
    }
        
    // plots a city with the specified latitude and longitude on the map
    public static void plotCity(Graphics g, int lat, int lon) {
        // Use convertRange to convert the latitude or longitude
        // to screen coordinates.
        int y = HEIGHT - BORDER - convertRange(lat, MIN_LAT, MAX_LAT, HEIGHT - 2 * BORDER);
        int x = BORDER + convertRange(lon, MIN_LON, MAX_LON, WIDTH - 2 * BORDER);
        g.fillOval(x, y, 2, 2);
    }
    
    // Takes a value, a range that it is within, and the size of a new
    // range. Converts the value to the new range. For example, if the
    // value is halfway between the rangeMin and rangeMax, it will be
    // converted to half of the size of the new range.
    public static int convertRange(int value, int rangeMin, int rangeMax, int newRange) {
        return (int)((value - rangeMin) * 1.0 / (rangeMax - rangeMin) * newRange);
    }
        
    // Draws the border and stats about how many cities were plotted.
    public static void graphStatic(Graphics g, int minPop, int cities) {
        g.setColor(Color.LIGHT_GRAY);
        g.fillRect(0, 0, WIDTH, BORDER);
        g.fillRect(0, HEIGHT - BORDER, WIDTH, BORDER);
        g.fillRect(0, 0, BORDER, HEIGHT);
        g.fillRect(WIDTH - BORDER, 0, BORDER, HEIGHT);
        
        g.setColor(Color.BLACK);
        g.drawString("Cities with at least " + minPop + " people", 10, 20);
        g.drawString(cities + " cities plotted", 10, HEIGHT - 10);
    }
    
    // Introduces the program.
    public static void printIntro() {
        System.out.println("This program allows you to search through");
        System.out.println("United States census data from the year 2009");
        System.out.println("and plot cities depending on their population");
        System.out.println();
    }
}