import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.io.InputStreamReader;
import java.util.HashMap;

public class RandomShell implements Runnable {

	protected transient HashMap<String, RandomWrapper> rnds;
	protected BufferedReader reader;
	protected PrintWriter writer;
	protected InputStream in;
	protected OutputStream out;
	protected ExitFunction exitFunc;
	
	public RandomShell() {
		rnds = new HashMap<String, RandomWrapper>();
		reader = null;
	}
	
	public void setInputStream(InputStream in) {
		this.in = in;
		reader = new BufferedReader(new InputStreamReader(this.in));
	}
	
	public void setOutputStream(OutputStream out) {
		this.out = out;
		writer = new PrintWriter(out);
	}
	
	public void setExitFunction(ExitFunction efunc) {
		this.exitFunc = efunc;
	}
	
	public boolean ExecCmd(String cmd) {
		String[] splitedCmd = cmd.split(" ");
		switch(splitedCmd[0]) {
		case "exit":
			if(splitedCmd.length > 1) {
				try {
					this.exitFunc.exit(Integer.parseInt(splitedCmd[1]));
				} catch (NumberFormatException e) {
					writer.println("The exit code could not be parsed: " + e.getMessage());
					return false;
				}
			} else {
				this.exitFunc.exit(0);
			}
			break;
		case "new":
			if(splitedCmd.length < 3) {
				writer.println("The command was not used correctly: new [CLASS] [NAME]");
				writer.println("Example: new generator generator");
				return false;
			} else {
				switch(splitedCmd[1]) {
				case "generator":
				case "g":
					rnds.put(splitedCmd[2], new RandomWrapper());
					break;
				default:
					writer.println("The specified class could not be found.");
					return false;
				}
			}
			break;
		case "generate":
			if(splitedCmd.length < 2) {
				writer.println("The command was not used correctly: generate [GENERATOR]");
				return false;
			} else if(! rnds.containsKey(splitedCmd[1])) {
				writer.println("The name of the generator was not found.");
				return false;
			} else {
				rnds.get(splitedCmd[1]).generate();
			}
			break;
		case "next":
			if(splitedCmd.length < 2) {
				writer.println("The command was not used correctly: next [GENERATOR]");
				return false;
			} else if(! rnds.containsKey(splitedCmd[1])) {
				writer.println("The random integer generator was not found.");
				return false;
			} else {
				try {
					writer.println(rnds.get(splitedCmd[1]).next());
				} catch (NoRandomIntegerGenerated e) {
					writer.println("No random integer was previously generated: " + e.getMessage());
					return false;
				}
			}
			break;
		case "reshape":
			if(splitedCmd.length < 4) {
				writer.println("The command was not used correctly: reshape [ID] [FROM] [TO]");
				return false;
			} else if(! rnds.containsKey(splitedCmd[1])) {
				writer.println("The random integer generator was not found.");
				return false;
			} else {
				try {
					int from = Integer.parseInt(splitedCmd[2]);
					int to = Integer.parseInt(splitedCmd[3]) + 1;
					int num = Math.abs(rnds.get(splitedCmd[1]).next());
					writer.println(num % (to - from) + from);
				} catch (NoRandomIntegerGenerated e) {
					writer.println("No random integer was previously generated: " + e.getMessage());
					return false;
				} catch (NumberFormatException e) {
					writer.println("No random integer was previously generated: " + e.getMessage());
					return false;
				}
			}
			break;
		case "loop":
			try {
				int cnt = Integer.parseInt(splitedCmd[1]);
				int beg = cmd.indexOf(' ', cmd.indexOf(' ') + 1) + 1;
				if(beg == -1 || beg == 0) {
					writer.println("The command was not used correctly: loop [COUNT] [COMMAND]");
					return false;
				}
				for(int i = 0; i < cnt; i++) {
					if(! ExecCmd(cmd.substring(beg)))
						break;
				}
			} catch (NumberFormatException e) {
				writer.println("The number could not be parsed: " + e.getMessage());
				return false;
			}
			break;
		case "echo":
			writer.println(cmd.substring(cmd.indexOf(' ') + 1));
			break;
		default:
			writer.println("The specified command could not be found.");
			return false;
		}
		return true;
	}
	
	@Override
	public void run() {
		while(true) {
			this.writer.print("> ");
			this.writer.flush();
			try {
				String readedCmd = this.reader.readLine().trim();
				ExecCmd(readedCmd);
			} catch (IOException e) {
				this.writer.println("Error: Couldn't read the command.");
				this.writer.println(e.getMessage());
			}
		}
	}

	public static void main(String[] args) {
		RandomShell shell = new RandomShell();
		shell.setInputStream(System.in);
		shell.setOutputStream(System.out);
		shell.setExitFunction((code) -> { System.exit(code); });
		
		Thread tr = new Thread(shell);
		tr.start();
		try {
			tr.join();
		} catch (InterruptedException e) {
			System.out.println("Interrupted: " + e.getMessage());
		}
	}
	
}