package org.gitlab4j.api;

import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.Stream;

import javax.ws.rs.core.GenericType;
import javax.ws.rs.core.Response;

import org.gitlab4j.api.models.Application;

/**
 * This class implements the client side API for the GitLab Applications API.
 * See <a href="https://docs.gitlab.com/ce/api/applications.html">Applications API at GitLab</a> for more information.
 */
public class ApplicationsApi extends AbstractApi {

    public ApplicationsApi(GitLabApi gitLabApi) {
        super(gitLabApi);
    }

    /**
     * Get all OATH applications.
     *
     * <pre><code>GitLab Endpoint: GET /api/v4/applications</code></pre>
     *
     * @return a List of OAUTH Application instances
     * @throws GitLabApiException if any exception occurs
     */
    public List<Application> getApplications() throws GitLabApiException {
        return (getApplications(getDefaultPerPage()).all());
    }

    /**
     * Get all OAUTH applications using the specified page and per page setting
     *
     * <pre><code>GitLab Endpoint: GET /api/v4/applications</code></pre>
     *
     * @param page the page to get
     * @param perPage the number of items per page
     * @return a list of OAUTH Applications in the specified range
     * @throws GitLabApiException if any exception occurs
     */
    public List<Application> getApplications(int page, int perPage) throws GitLabApiException {
        Response response = get(javax.ws.rs.core.Response.Status.OK, getPageQueryParams(page, perPage), "applications");
        return (response.readEntity(new GenericType<List<Application>>() {}));
    }

    /**
     * Get a Pager of all OAUTH applications.
     *
     * <pre><code>GitLab Endpoint: GET /api/v4/applications</code></pre>
     *
     * @param itemsPerPage the number of items per page
     * @return a Pager of Application instances in the specified range
     * @throws GitLabApiException if any exception occurs
     */
    public Pager<Application> getApplications(int itemsPerPage) throws GitLabApiException {
        return (new Pager<Application>(this, Application.class, itemsPerPage, null, "applications"));
    }

    /**
     * Get a Stream of all OAUTH Application instances.
     *
     * <pre><code>GitLab Endpoint: GET /api/v4/applications</code></pre>
     *
     * @return a Stream of OAUTH Application instances
     * @throws GitLabApiException if any exception occurs
     */
    public Stream<Application> getApplicationsStream() throws GitLabApiException {
        return (getApplications(getDefaultPerPage()).stream());
    }

    /**
     * Create an OAUTH Application.
     *
     * <pre><code>GitLab Endpoint: POST /api/v4/applications</code></pre>
     *
     * @param name the name for the OAUTH Application
     * @param redirectUri the redirect URI for the OAUTH Application
     * @param scopes the scopes of the application (api, read_user, sudo, read_repository, openid, profile, email)
     * @return the created Application instance
     * @throws GitLabApiException if any exception occurs
     */
    public Application createApplication(String name, String redirectUri, ApplicationScope[] scopes) throws GitLabApiException {

        if (scopes == null || scopes.length == 0) {
            throw new GitLabApiException("scopes cannot be null or empty");
        }

        return (createApplication(name, redirectUri, Arrays.asList(scopes)));
    }

    /**
     * Create an OAUTH Application.
     *
     * <pre><code>GitLab Endpoint: POST /api/v4/applications</code></pre>
     *
     * @param name the name for the OAUTH Application
     * @param redirectUri the redirect URI for the OAUTH Application
     * @param scopes the scopes of the application (api, read_user, sudo, read_repository, openid, profile, email)
     * @return the created Application instance
     * @throws GitLabApiException if any exception occurs
     */
    public Application createApplication(String name, String redirectUri, List<ApplicationScope> scopes) throws GitLabApiException {

        if (scopes == null || scopes.isEmpty()) {
            throw new GitLabApiException("scopes cannot be null or empty");
        }

        String scopesString = scopes.stream().map(ApplicationScope::toString).collect(Collectors.joining(","));
        GitLabApiForm formData = new GitLabApiForm()
                .withParam("name", name, true)
                .withParam("redirect_uri", redirectUri, true)
                .withParam("scopes",  scopesString, true);
        Response response = post(Response.Status.CREATED, formData, "applications");
        return (response.readEntity(Application.class));
    }

    /**
     * Delete the specified OAUTH Application.
     *
     * <pre><code>GitLab Endpoint: DELETE /api/v4/applications/:applicationId</code></pre>
     *
     * @param applicationId the ID of the OUAUTH Application to delete
     * @throws GitLabApiException if any exception occurs
     */
    public void deleteApplication(Integer applicationId) throws GitLabApiException {
        delete(Response.Status.NO_CONTENT, null, "applications", applicationId);
    }
}