package ui.tui;

import model.asn1.exceptions.ParseException;
import model.ca.Template;
import model.x501.Name;

/**
 * The screen that modifies the properties of a single template and add it to the store.
 */
public class TemplateSetScreen implements UIHandler {
    private final JCA session;

    /**
     * EFFECTS: Init with session.
     */
    public TemplateSetScreen(JCA session) {
        this.session = session;
    }

    private Template template;

    /**
     * EFFECTS: Print help
     */
    @Override
    public void help() {
        System.out.println("show\tView the current template settings\n"
                + "set\tSet key value\n"
                + "commit\tSave the template\n"
                + "exit\tDiscard changes\n"
                + "help\tPrint this help message\n");
    }

    /**
     * EFFECTS: Parse and set / unset the subject of the template
     * MODIFIES: this
     */
    private void handleSetSubject(String val) {
        try {
            if (val == null) {
                template = new Template(template.getName(), template.isEnabled(), (Name) null, template.getValidity());
            } else {
                template = new Template(template.getName(), template.isEnabled(), val, template.getValidity());
            }
        } catch (ParseException e) {
            System.out.println(e.getMessage());
        }
    }

    /**
     * EFFECTS: Set the validity of the template to the given integer
     * MODIFIES: this
     */
    private void handleSetValidity(String val) {
        if (val == null) {
            System.out.println("Cannot unset validity");
            return;
        }
        try {
            long i = Long.parseLong(val);
            if (i <= 0) {
                System.out.println("Invalid validity days");
                return;
            }
            template = new Template(template.getName(), template.isEnabled(), template.getSubject(), i);
        } catch (NumberFormatException ignored) {
            System.out.println("Invalid validity days");
        }
    }

    /**
     * EFFECTS: Handle the `set` command.
     * MODIFIES: this
     */
    private void handleSet(String... args) {
        if (args.length != 2 && args.length != 3) {
            System.out.println("Usage: set <key> <value>");
            System.out.println("Supported keys: subject validity");
            return;
        }
        String val = args.length == 3 ? args[2] : null;
        switch (args[1]) {
            case "subject":
                handleSetSubject(val);
                break;
            case "validity":
                handleSetValidity(val);
                break;
            default:
                System.out.println("Unknown key");
                break;
        }
    }

    /**
     * EFFECTS: Add the template to store and switch to templates screen.
     * MODIFIES: session
     */
    @Override
    public void commit() {
        session.getCa().addTemplate(template);
        session.setUnsaved(true);
        session.setScreen(Screen.TEMPLATES);
    }

    /**
     * EFFECTS: Show template info.
     */
    @Override
    public void show() {
        System.out.println("Subject:\t" + template.getSubject());
        System.out.println("Validity:\t" + template.getValidity() + " days");
    }

    /**
     * EFFECTS: Handle commands
     */
    @Override
    public void command(String... args) {
        switch (args[0]) {
            case "set":
                handleSet(args);
                break;
            default:
            case "help":
                help();
                break;
        }
    }

    /**
     * EFFECTS: Return to templates list and clear the current template in editing.
     */
    @Override
    public Screen exit() {
        template = null;
        return Screen.TEMPLATES;
    }

    /**
     * EFFECTS: yuuta@JCA /templates/name/ %
     */
    @Override
    public String getPS1() {
        return String.format("/templates/%s/ %%", template.getName());
    }

    /**
     * EFFECT: Edit args[0].
     * REQUIRES: args.length = 1; args[0] instanceof Template
     * MODIFIES: args[0]
     */
    @Override
    public void enter(Object... args) {
        template = (Template) args[0];
    }
}