package com.dexels.oauth.web;

import java.util.HashSet;
import java.util.Set;
import java.util.regex.Pattern;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.dexels.oauth.api.Client;
import com.dexels.oauth.api.ClientStoreFactory;
import com.dexels.oauth.api.Scope;
import com.dexels.oauth.api.ScopeStoreFactory;
import com.dexels.oauth.web.exceptions.OAuthClientException;
import com.dexels.oauth.web.exceptions.OAuthServerException;

public abstract class OAuthCommandBase {

    private static final Pattern VALID_EMAIL_ADDRESS_REGEX = Pattern
            .compile("^[A-Z0-9._%+-]+@[A-Z0-9.-]+\\.[A-Z]{2,6}$", Pattern.CASE_INSENSITIVE);

    protected HttpServletRequest request;
    protected HttpServletResponse response;
    protected Client client;
    protected String tenant;
    protected Set<Scope> scopes = new HashSet<>();

    public OAuthCommandBase(HttpServletRequest request, HttpServletResponse response) throws OAuthClientException {
        this.request = request;
        this.response = response;

        tenant = request.getParameter("tenant");
        if (tenant == null) {
            throw new OAuthClientException("Missing tenant parameter");
        }

        String clientId = request.getParameter("client_id");
        if (clientId == null) {
            throw new OAuthClientException("Missing client_id parameter");
        }
        client = ClientStoreFactory.getInstance().find(tenant, clientId);
        if (client == null) {
            throw new OAuthClientException("Invalid client_id");
        }

        String scopesString = request.getParameter("scope");
        if (scopesString != null && !scopesString.trim().equals("")) {
            String splitter = " ";
            if (scopesString.contains(",")) {
                splitter = ",";
            }

            for (String scopeString : scopesString.split(splitter)) {
                // check if the requested scope exists in the scopestore
                Scope scope = ScopeStoreFactory.getInstance().getScope(tenant, scopeString);
                if (scope != null) {
                    // check if we don't have this scope already and if it's part of this client
                    // optional scopes
                    if (!scopes.contains(scope) && client.getOptionalScopes().contains(scope)) {
                        scopes.add(scope);
                    }
                } else {
                    throw new OAuthClientException("The requested scope is invalid, unknown, or malformed.");
                }
            }
        }
    }

    public abstract void execute() throws OAuthServerException;

    protected String createAbsolute(String relative) {
        String forwardedProto = request.getHeader("X-Forwarded-Proto");
        String host = request.getHeader("Host");

        if (forwardedProto == null) {
            forwardedProto = "http";
        }

        return String.format("%s://%s%s", forwardedProto, host, relative);
    }

    protected boolean isValidPassword(String password) {
        return password != null && password.length() >= 8;
    }

    protected boolean isValidUsername(String username) {
        return username != null && VALID_EMAIL_ADDRESS_REGEX.matcher(username).find() && username.length() < 64;
    }

}