package net.tuschhcm.routercontrol;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;

/**
 * Class to represent a router preset.
 */
public class Preset {
    private static final String UNNAMED = "<Unnamed Preset>";

    /**
     * Name of the preset.
     */
    private String mName;

    /**
     * List of inputs for outputs.
     * List index corresponds with the output.
     */
    private final ArrayList<Integer> mInputs;

    /**
     * Load a preset from the given file.
     *
     * @param file The file to load.
     * @return the Preset object
     * @throws IllegalArgumentException if the preset can't be loaded.
     */
    public static Preset loadPresetFile(File file) throws IllegalArgumentException {
        try {
            Preset preset = new Preset();

            BufferedReader in = new BufferedReader(new FileReader(file));
            int lineno = 1;

            String line = in.readLine();
            if (line == null) {
                throw new IllegalArgumentException("Empty preset file: " + file);
            }

            // The name is optional and starts with a #
            if (line.charAt(0) == '#') {
                preset.mName = line.substring(1).trim();
                line = in.readLine();
                lineno++;
            }

            // Read the inputs.
            int output = 1;
            while (line != null && !line.equals("")) {
                try {
                    final Integer input = Integer.valueOf(line.trim());
                    preset.mInputs.add(input);
                    output++;

                } catch (final NumberFormatException nfe) {
                    throw new IllegalArgumentException(
                        String.format("%s: Input set for output %d on line %d is not a number.",
                                file, output, lineno));
                }

                line = in.readLine();
                lineno++;
            }

            in.close();

            return preset;

        } catch (final IOException e) {
            throw new IllegalArgumentException("Could not read " + file, e);
        }
    }

    /**
     * Constructor for Preset.
     */
    public Preset() {
        mName = UNNAMED;
        mInputs = new ArrayList<Integer>();
    }

    /**
     * Get the name of the preset.
     *
     * @return The preset name
     */
    public String getName() {
        return mName;
    }

    /**
     * Get an input for the given output.
     *
     * @param output
     * @return Input number, or 0 if no change.
     * @throws IllegalArgumentException if the output isn't defined.
     */
    public int getInputForOutput(final int output) {
        final int index = output - 1;
        if (index < 0 || index > mInputs.size()) {
            throw new IllegalArgumentException("Output out of range.");
        }

        return mInputs.get(output);
    }

    /**
     * @return The number of outputs defined in this preset.
     */
    public int getNumberOfOutputs() {
        return mInputs.size();
    }

    /**
     * Return a string representation of this preset.
     */
    public String toString() {
        String str = "";
        if (!mName.equals(UNNAMED)) {
            str = "# " + mName + "\n";
        }

        for (Integer in : mInputs) {
            str += in + "\n";
        }

        return str;
    }
}