/*
    PlayDungeon2.java
    CIS 250
    2014-03-11
    David Klick

    Modified 2017-02-11
      - added ITEM as a valid data input for dungeon
      - added ability for rooms to hold objects
      - added ability for player to carry objects
      - added additional commands to parser: inv, take, drop, help
      - revamped parser to handle two word commands
      - added code to support an actual goal
      - added a considerable amount of debugging information
      
    This is the driver to play a simple text-based dungeon
    game. The coding may be a bit rough since this was originally
    a conversion from a C++ version.
*/

import java.io.BufferedReader;
import java.io.File;
import java.io.IOException;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.FileSystem;
import java.nio.file.FileSystems;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.List;
import java.util.NoSuchElementException;
import java.util.Scanner;

public class PlayDungeon2 {
    public static void main(String[] args) {
        Room room;
        Path path;
        LinkedList<Item> inv = new LinkedList<Item>();
        boolean done = false;
        String fileName = "dungeon.txt";
        int datafileCount = 0;
        int i;
        boolean debug = false;
        boolean error = false;
        String action, object;
        
        // create dungeon
        Dungeon dungeon = new Dungeon();
        
        // parse options and arguments to program
        for (i=0; i<args.length; i++) {
            if (args[i].equalsIgnoreCase("-d")) {
                debug = true;
            } else if ((args[i].length() > 0) && (args[i].charAt(0) == '-')) {
                System.err.println("Unrecognized option: " + args[i]);
                error = true;
            } else {
                if (datafileCount > 1) {
                    System.err.println("Error: Multiple data files specified");
                    System.err.println("Usage: java PlayDungeon datafileName");
                    error = true;
                } else {
                    fileName = args[i];
                    datafileCount++;
                }
            }
        }
        
        // end program if error encountered
        if (error) System.exit(1);
        
        // read in data file to populate dungeon
        readFile(dungeon, fileName);
    
        // initialize dungeon
        if (dungeon.rooms.length() == 0) {
            System.err.println("Error: No rooms in dungeon");
            System.exit(4);
        }
        if (dungeon.currentRoom.length() == 0) {
            dungeon.currentRoom = dungeon.rooms.get(0).id;
        }

        // display debugging info if requested
        if (debug) {
            System.out.println("Debugging information:");
            System.out.println("Number of rooms: " + dungeon.rooms.length());
            System.out.println("List of rooms:");
            for (int j=0; j<dungeon.rooms.length(); j++) {
                room = dungeon.rooms.get(j);
                System.out.println("  Room #" + j + ": " + room.id);
                if (room.paths.length() > 0) System.out.println("    Paths:");
                for (int k=0; k<room.paths.length(); k++) {
                    System.out.println("      " + room.paths.get(k));
                }
                if (room.items.length() > 0) System.out.println("    Items:");
                for (int m=0; m<room.items.length(); m++) {
                    System.out.println("      " + room.items.get(m));
                }
                
            }
            System.out.println("Starting room: " + dungeon.currentRoom);
            System.out.println("And now... on to the game\n\n");
        }
    
        // play the game
        Scanner kbd = new Scanner(System.in);
        while (!done) {
            Room current = dungeon.getRoom(dungeon.currentRoom);
            if (current == null) throw new NoSuchElementException("Error: Current room is unknown.\n");
            describeRoom(current);
            if (current.id.equalsIgnoreCase("outside")) {
                System.out.println("Congratulations! You have won the game.");
                done = true;
                break;
            }
            System.out.print("\nEnter command: ");
            String command = kbd.nextLine().toLowerCase();
            String[] commands = command.split(" ");
            
            if (commands.length == 0 || commands.length > 2) System.out.println("Command not understood");
            else { // command is one or two tokens long
                action = commands[0];
                object = (commands.length > 1) ? commands[1] : null;
                if (action.equals("go")) {
                    action = object;
                    object = null;
                }
                switch (action) {
                    case "drop":
                        if (object == null) System.out.println("You must specify an object to drop");
                        else {
                            for (i=inv.length()-1; i>=0; i--) {
                                Item item = inv.get(i);
                                if (item.name.equals(object) || object.equals("all")) {
                                    current.items.add(item);
                                    inv.remove(item);
                                    if (!object.equals("all")) break;
                                }
                            }
                            Item item1 = findItem(current, "bike");
                            Item item2 = findItem(current, "instructor");
                            if (item1 != null && item2 != null) {
                                current.items.remove(item1);
                                current.items.remove(item2);
                                System.out.println("The instructor wakes up and gets on the bike.");
                                System.out.println("Before you can ask him what's happening, he pedals off");
                                System.out.println("and leaves the building going south from the east hall.");
                                Path p = new Path("s", "outside");
                                Room r = dungeon.getRoom("east hall south");
                                r.paths.add(p);
                                r.description = r.description.replace(" locked", " now unlocked");
                                r.visited = false;
                            }
                        }
                        break;
                    case "take":
                        if (object == null) System.out.println("You must specify an object to take");
                        else {
                            for (i=current.items.length()-1; i>=0; i--) {
                                Item item = current.items.get(i);
                                if (item.name.equals(object) || object.equals("all")) {
                                    inv.add(item);
                                    current.items.remove(item);
                                    break;
                                }
                            }
                        }
                    case "inv":
                        StringBuilder sb = new StringBuilder("You are carrying: ");
                        if (inv.length() == 0) sb.append("nothing");
                        else {
                            for (i=0; i<inv.length(); i++) {
                                if (i > 0) sb.append(", ");
                                sb.append(inv.get(i).name);
                            }
                        }
                        System.out.println(sb.toString());
                        break;
                    case "quit":
                        done = true;
                        break;
                    case "exit":
                        System.out.println("Use 'quit' to end the game.");
                        break;
                    case "help":
                        System.out.println("Commands are: help, quit, look, drop, take, go, inv, and the exit directions");
                        break;
                    case "look":
                        current.visited = false;
                        break;
                    default:
                        path = current.getPath(action);
                        if (path == null) {
                            System.out.println("Unknown command. Try again.");
                        } else {
                            room = dungeon.getRoom(path.to);
                            if (room == null) {
                                System.out.println("Path doesn't lead to a known room.");
                            } else {
                                dungeon.currentRoom = room.id;
                            }
                        }
                } 
            }
        }
        System.out.println("Thanks for playing. Visit again soon.");
    }

    private static Item findItem(Room room, String itemName) {
        for (int i=0; i<room.items.length(); i++) {
            if (room.items.get(i).name.equalsIgnoreCase(itemName)) return room.items.get(i);
        }
        return null;
    }
    
    // routine to process a dungeon data file
    // this will throw an exception if it has any problems
    private static void readFile(Dungeon dungeon, String filename) {
        List<String> dataLines = new ArrayList<>();
        
        File dataFile = new File(filename);
        if (!dataFile.exists() || !dataFile.canRead()) {
            System.err.println("Error: Could not open/read data file");
            System.exit(1);
        }
        try {
            java.nio.file.Path dataPath = FileSystems.getDefault().getPath(filename);
            dataLines = Files.readAllLines(dataPath, StandardCharsets.UTF_8);
        } catch (IOException e) {
            System.err.println("Error: I/O error while processing data file");
            System.exit(2);
        }

        String previousLine = "";
        for (String linein : dataLines) {
            if (linein.length() == 0) continue;
            if (linein.startsWith("ROOM:") || linein.startsWith("PATH:") 
                || linein.startsWith("ITEM:") || linein.startsWith("INIT:")) {
                processLine(dungeon, previousLine);
                previousLine = "";
            }
            if (previousLine.length() > 0) previousLine = previousLine + " ";
            previousLine = previousLine + trim$(linein);
        }
        processLine(dungeon, previousLine);

    }

    // routine to process one line of a dungeon data file
    // this will throw an exception if it has any problems
    private static void processLine(Dungeon dungeon, String line) {
        String[] fields;
        if (line.startsWith("ROOM:") || line.startsWith("PATH:") || line.startsWith("ITEM:")) {
            fields = line.split(":");
            if (fields.length < 4) {
                System.err.println("Error: Problem parsing data file");
                System.err.println("    " + line);
                System.exit(3);
            }
            fields[0] = trim$(fields[0]);
            fields[1] = trim$(fields[1]);
            fields[2] = trim$(fields[2]);
            fields[3] = trim$(fields[3]);
            if (line.startsWith("ROOM:")) {
                if (dungeon.getRoom(fields[1]) != null) {
                    System.err.println("Error: Duplicate room ID found in data file");
                    System.exit(3);
                }
                dungeon.rooms.add(new Room(fields[1], fields[2], fields[3]));
            } else if (line.startsWith("PATH")) {
                Room roomSrc = dungeon.getRoom(fields[2]);
                Room roomDest = dungeon.getRoom(fields[3]);
                if (roomSrc == null) {
                    System.err.printf("Error: Path from unknown room (%s) encountered in data file%n", fields[2]);
                    System.err.println("    " + line);
                    System.exit(3);
                }
                if (roomDest == null) {
                    System.err.printf("Error: Path to unknown room (%s) encountered in data file%n", fields[3]);
                    System.err.println("    " + line);
                    System.exit(3);
                }
                Path path = roomSrc.getPath(fields[1]);
                if (path != null) {
                    System.err.printf("Error: Duplicate path from room (%s) encountered in data file%n", fields[2]);
                    System.err.println("    " + line);
                    System.exit(3);
                }
                roomSrc.paths.add(new Path(fields[1], fields[3]));
            } else {  // must be an ITEM
                Room room = dungeon.getRoom(fields[3]);
                if (room == null) {
                    System.out.println("Room for item not found (" + room.id + ")");
                } else {
                    room.items.add(new Item(fields[1], fields[2], fields[3]));
                }
            }
        } else if (line.startsWith("INIT:")) {
            fields = line.split(":");
            dungeon.currentRoom = trim$(fields[1]);
        }
        return;
    }

    private static String ltrim$(String s) {
        if (s == null) return "";
        StringBuilder sb = new StringBuilder(s);
        while (sb.length() > 0 && Character.isWhitespace(sb.charAt(0)))
            sb.deleteCharAt(0);
        return sb.toString();
    }

    private static String rtrim$(String s) {
        if (s == null) return "";
        StringBuilder sb = new StringBuilder(s);
        while (sb.length() > 0 && Character.isWhitespace(sb.charAt(sb.length()-1)))
            sb.deleteCharAt(sb.length()-1);
        return sb.toString();
    }

    private static String trim$(String s) {
        return s==null ? "" : ltrim$(rtrim$(s));
    }

    // prints room description
    // diplays short description if room is marked as
    //     visited and long description otherwise
    private static void describeRoom(Room room) {
        int i;
        System.out.println("You are in " + room.name);
        if (!room.visited) System.out.println(room.description);
        if (room.paths.length() == 0) {
            System.out.println("There are no exits");
        } else {
            for (i=0; i<room.items.length(); i++) {
                System.out.println(room.items.get(i).description);
            }
            System.out.print("Exits are: ");
            for (i=0; i<room.paths.length(); i++) {
                if (i > 0) System.out.print(", ");
                System.out.print(room.paths.get(i).direction);
            }
            System.out.println();
        }
        room.visited = true;
    }
}