// CSE 373 Homework 8: Six Degrees of Kevin Bacon
// YOU DO NOT NEED TO MODIFY THIS INSTRUCTOR-PROVIDED FILE.
// Your code should work properly with an unmodified version of this file.

import java.util.*;
import java.io.*;

/**
 * This is the main client program to run your Kevin Bacon simulation.
 * It uses your BaconNumberFinder.
 */
public class MainKevinBacon {
	// input file to use if user does not type one
	private static final String DEFAULT_INPUT_FILENAME = "movies.txt";
	
	// % of movies in file to add to graph
	private static final double DEFAULT_PERCENT = 100.0;
	
	/**
	 * Runs the program.
	 */
	public static void main(String[] args) throws IOException {
		// console input
		printIntro();
		Scanner console = new Scanner(System.in);
		File file = openFile(console);
		System.out.print("Show runtimes of each search (Y/N, Enter for N)? ");
		boolean showTimes = console.nextLine().trim().toLowerCase().startsWith("y");
		double percent = getPercent(console);
		
		// create and fill the graph
		Graph<String, String> graph = buildGraph(console, file, percent);
		BaconNumberFinder finder = new BaconNumberFinder(graph);
		
		// prompt for actors and show their Bacon numbers/paths
		String actor = getActorName(console);
		while (actor.length() > 0) {
			long startTime = System.currentTimeMillis();
			finder.findBaconNumber(actor);
			long endTime = System.currentTimeMillis();
			if (showTimes && endTime != startTime) {
				System.out.println("(took " + (endTime - startTime) + " ms)");
			}
			actor = getActorName(console);
		}
		System.out.println("Exiting.");
	}
	
	/**
	 * Displays an introductory message explaining the program to the user.
	 */
	public static void printIntro() {
		System.out.println("Welcome to the Six Degrees of Kevin Bacon.");
		System.out.println("If you tell me an actor's name, I'll connect them to Kevin Bacon");
		System.out.println("through the movies they've appeared in.  I bet your actor has");
		System.out.println("a Kevin Bacon number of six or less!");
		System.out.println();
	}
	
	/**
	 * Prompts the user to enter a file name containing movie input data.
	 * Defaults to "movies.txt".
	 * If the user types a partial file name, ".txt" suffix will be added.
	 */
	public static File openFile(Scanner console) {
		System.out.print("Movies file name to open (Enter for " + DEFAULT_INPUT_FILENAME + ")? ");
		String filename = console.nextLine().trim();
		if (filename.length() > 0 && !filename.contains(".")) {
			filename = filename + ".txt";   // shorthand, can type "foo" -> "foo.txt"
		}
		if (filename.length() == 0) {
			filename = DEFAULT_INPUT_FILENAME;
		}
		return new File(filename);
	}
	
	/**
	 * Reads the given input file data and uses it to construct and return a
	 * graph of actors and the movies they have appeared in.
	 * Throws a FileNotFoundException if the input file is not found.
	 * @precondition 0 < percent <= 100.0
	 */
	public static Graph<String, String> buildGraph(Scanner console, File file, double percent)
			throws IOException {
		Graph<String, String> graph = new SearchableGraph<String, String>();
		int everyNth = (int) Math.max(1, (int) (100.0 / percent));
		BufferedReader reader = new BufferedReader(new FileReader(file));
		int count = 0;
		while (reader.ready()) {
			count++;
			String line = reader.readLine();
			if (everyNth != 1 && count % everyNth != 0) {
				// keep all lines that relate to Kevin Bacon
				if (!line.contains("Kevin Bacon")) {
					continue;
				}
			}
			
			int colons = line.indexOf(";;;");
			if (colons < 0) {
				continue;
			}
			String movie = line.substring(0, colons);
			String[] actors = line.substring(colons + 3).split(", ");
			for (String actor : actors) {
				graph.addVertex(actor);
			}
			
			// connect all of the actors
			for (int i = 0; i < actors.length; i++) {
				for (int j = i + 1; j < actors.length; j++) {
					if (!actors[i].equals(actors[j])) {
						graph.addEdge(actors[i], actors[j], movie);
					}
				}
			}
			
			if (count > 0 && count % 10000 == 0) {
				System.out.println("  movie #" + count + " ...");
			}
		}
		
		return graph;
	}
	
	/**
	 * Prompts the user to type an actor's name and returns the name typed.
	 */
	public static String getActorName(Scanner console) {
		System.out.println();
		System.out.print("Actor's name (Enter to quit)? ");
		String actor = console.nextLine().trim();
		return actor;
	}
	
	/**
	 * Prompts the user to type a percentage of movies in the input file to use,
	 * and returns the percentage typed, defaulting to 100.0.
	 */
	public static double getPercent(Scanner console) {
		System.out.printf("Percentage of movies to include (Enter for %.0f)? ", DEFAULT_PERCENT);
		String percentStr = console.nextLine().trim();
		double percent = DEFAULT_PERCENT;
		try {
			if (percentStr.length() > 0) {
				percent = Math.max(0.00001, Math.min(100.0, Double.parseDouble(percentStr)));
			}
		} catch (NumberFormatException nfe) {
			percent = DEFAULT_PERCENT;
		}
		if (percent == 100.0) {
			System.out.println("Reading input file ...");
		} else {
			System.out.println("Reading input file (" + percent + "% of elements) ...");
		}
		return percent;
	}
}