/*
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 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */

package main;

import java.io.IOException;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Arrays;
import java.util.NoSuchElementException;
import java.util.Scanner;
import java.util.Set;

/**
 *
 * @author s123188
 */
public class FarmShell {
    
    private final Scanner scanner = new Scanner(System.in);
    
    Analyzor analyzor;
    
    /*
    private void printPrompt() {
        if (stream_cached == null) {
            // "dollars are worthless"
            System.out.print("$ ");
        } else if (stream_cached.isValid()) {
            // "we make money now by receiving tweets"
            System.out.print("€ ");
        } else {
            // "we previously made money, but not anymore"
            System.out.print("ƒ ");
        }
    }
*/
    /**
     * Processes commands from stdin until the exit command is received or EOF.
     */
    public void process_forever() {
        System.err.println("Entering interactive shell, type 'help' for help "
                + "or 'exit' to leave. '.' repeats the previous interactive "
                + "command.");
        // print prompt for reading first command
        //printPrompt();
        String lastLine = "";
        while (scanner.hasNextLine()) {
            String line = scanner.nextLine().trim();
            // repeat last command
            if (line.equals(".")) {
                line = lastLine;
            }
            if (!execute(line)) {
                // requested to terminate
                break;
            }
            if (!line.isEmpty()) {
                lastLine = line;
            }
            // print prompt for reading next line
            //printPrompt();
        }
        // prevent corrupted compressed files when exiting without a command
        throw new NoSuchElementException();
    }

    public boolean execute(String cmd) {
        String[] args = cmd.trim().split("\\s+", 2);
        if (!args[0].isEmpty()) {
            // non-empty command, let's see whether it makes sense?
            return execute(args);
        }
        return true;
    }

    /**
     * Executes a command with optional parameters.
     *
     * @param args An array with the first argument containing the command with
     * optional parameters in following arguments.
     * @return true if more commands are allowed to be executed, false
     * otherwise.
     */
    public boolean execute(String[] args) {
        //make a new Analyzor
        analyzor = new Analyzor();
        
        try {
            Command command = Command.fromString(args[0]);
            String[] params = Arrays.copyOfRange(args, 1, args.length);
            execute(command, params);
        } catch (IllegalArgumentException ex) {
            System.err.println(ex.getMessage());
        } catch (IOException ex) {
            System.err.println("Command " + args[0] + " failed with " + ex);
            ex.printStackTrace();
        } catch (NoSuchElementException ex) {
            // thrown by the "exit" command to signal exit
            return false;
        }
        // another satisfied customer, next!
        return true;
    }

    enum Command {
        
        query("make a query to the database; needed to do analysis", 1),
        filterbots("marks all users as bot or not"),
        sentiment("analyzes all tweets on positivity (about a brand)"),
        exit("Returns to shell"),
        help("Get help");

        private final String description;
        private final int paramCount;

        Command(String description) {
            this.description = description;
            this.paramCount = 0;
        }

        Command(String description, int paramCount) {
            this.description = description;
            this.paramCount = paramCount;
        }

        public String getDescription() {
            return description;
        }

        public int getParamCount() {
            return paramCount;
        }

        public static Command fromString(String command) {
            for (Command cmd : values()) {
                if (cmd.name().equals(command)) {
                    return cmd;
                }
            }
            throw new IllegalArgumentException("Unrecognized command. Hint: help");
        }
    };

    private final String[] HELP = new String[]{
        "Interactive TweetShell",
        "",
        "Available commands:"
    };

    private void execute(Command command, String[] params) throws IOException {
        if (params.length < command.getParamCount()) {
            throw new IllegalArgumentException("Expected "
                    + command.getParamCount() + " parameters, got only "
                    + params.length);
        }
        switch (command) {
            case query:
                analyzor.Query(params[0]);
                break;
            case filterbots:
                System.out.println("not yet implemented");
                break;
            case sentiment:
                analyzor.sentimentAnalysis();
                break;
            case help:
                for (String line : HELP) {
                    System.out.println(line);
                }
                for (Command cmd : Command.values()) {
                    System.out.printf("  %-10s", cmd.name());
                    if (!cmd.getDescription().isEmpty()) {
                        System.out.print(" " + cmd.getDescription());
                    }
                    if (cmd.getParamCount() == 1) {
                        System.out.print(" (1 arg)");
                    } else if (cmd.getParamCount() > 1) {
                        System.out.printf(" (%d args)", cmd.getParamCount());
                    }
                    System.out.println();
                }
                break;
            case exit:
                throw new NoSuchElementException();
            default:
                throw new AssertionError(command.name());
        }
    }
}