package com.box.sdk;

import java.net.URL;
import java.text.ParseException;
import java.util.Date;

import com.eclipsesource.json.JsonObject;
import com.eclipsesource.json.JsonValue;

/**
 * Represents a file version retention.
 * A retention policy blocks permanent deletion of content for a specified amount of time.
 * Admins can apply policies to specified folders, or an entire enterprise.
 * A file version retention is a record for a retained file version.
 *
 * @see <a href="https://docs.box.com/reference#file-version-retention-object">Box file version retention</a>
 *
 * <p>Unless otherwise noted, the methods in this class can throw an unchecked {@link BoxAPIException} (unchecked
 * meaning that the compiler won't force you to handle it) if an error occurs. If you wish to implement custom error
 * handling for errors related to the Box REST API, you should capture this exception explicitly.</p>
 */
@BoxResourceType("file_version_retention")
public class BoxFileVersionRetention extends BoxResource {

    /**
     * @see #getInfo(String...)
     */
    private static final URLTemplate RETENTION_URL_TEMPLATE = new URLTemplate("file_version_retentions/%s");

    /**
     * The URL template used for operation with file version retentions.
     */
    private static final URLTemplate ALL_RETENTIONS_URL_TEMPLATE = new URLTemplate("file_version_retentions");

    /**
     * The default limit of entries per response.
     */
    private static final int DEFAULT_LIMIT = 100;

    /**
     * Constructs a BoxFileVersionRetention for a resource with a given ID.
     *
     * @param api the API connection to be used by the resource.
     * @param id  the ID of the resource.
     */
    public BoxFileVersionRetention(BoxAPIConnection api, String id) {
        super(api, id);
    }

    /**
     * @param fields the fields to retrieve.
     * @return information about this retention policy.
     */
    public BoxFileVersionRetention.Info getInfo(String ... fields) {
        QueryStringBuilder builder = new QueryStringBuilder();
        if (fields.length > 0) {
            builder.appendParam("fields", fields);
        }
        URL url = RETENTION_URL_TEMPLATE.buildWithQuery(this.getAPI().getBaseURL(), builder.toString(), this.getID());
        BoxAPIRequest request = new BoxAPIRequest(this.getAPI(), url, "GET");
        BoxJSONResponse response = (BoxJSONResponse) request.send();
        JsonObject responseJSON = JsonObject.readFrom(response.getJSON());
        return new Info(responseJSON);
    }

    /**
     * Retrieves all file version retentions.
     * @param api the API connection to be used by the resource.
     * @param fields the fields to retrieve.
     * @return an iterable contains information about all file version retentions.
     */
    public static Iterable<BoxFileVersionRetention.Info> getAll(BoxAPIConnection api, String ... fields) {
        return getRetentions(api, new QueryFilter(), fields);
    }

    /**
     * Retrieves all file version retentions matching given filters as an Iterable.
     * @param api the API connection to be used by the resource.
     * @param filter filters for the query stored in QueryFilter object.
     * @param fields the fields to retrieve.
     * @return an iterable contains information about all file version retentions matching given filter.
     */
    public static Iterable<BoxFileVersionRetention.Info> getRetentions(
            final BoxAPIConnection api, QueryFilter filter, String ... fields) {
        filter.addFields(fields);
        return new BoxResourceIterable<BoxFileVersionRetention.Info>(api,
                ALL_RETENTIONS_URL_TEMPLATE.buildWithQuery(api.getBaseURL(), filter.toString()),
                DEFAULT_LIMIT) {

            @Override
            protected BoxFileVersionRetention.Info factory(JsonObject jsonObject) {
                BoxFileVersionRetention retention = new BoxFileVersionRetention(api, jsonObject.get("id").asString());
                return retention.new Info(jsonObject);
            }
        };
    }

    /**
     * Contains information about the retention policy.
     */
    public class Info extends BoxResource.Info {

        /**
         * @see #getFileVersion()
         */
        private BoxFileVersion fileVersion;

        /**
         * @see #getFile()
         */
        private BoxFile.Info file;

        /**
         * @see #getAppliedAt()
         */
        private Date appliedAt;

        /**
         * @see #getDispositionAt()
         */
        private Date dispositionAt;

        /**
         * @see #getWinningPolicy()
         */
        private BoxRetentionPolicy.Info winningPolicy;

        /**
         * Constructs an empty Info object.
         */
        public Info() {
            super();
        }

        /**
         * Constructs an Info object by parsing information from a JSON string.
         * @param  json the JSON string to parse.
         */
        public Info(String json) {
            super(json);
        }

        /**
         * Constructs an Info object using an already parsed JSON object.
         * @param  jsonObject the parsed JSON object.
         */
        Info(JsonObject jsonObject) {
            super(jsonObject);
        }

        /**
         * {@inheritDoc}
         */
        @Override
        public BoxResource getResource() {
            return BoxFileVersionRetention.this;
        }

        /**
         * @return the file version this file version retention was applied to.
         */
        public BoxFileVersion getFileVersion() {
            return this.fileVersion;
        }

        /**
         * @return the file this file version retention was applied to.
         */
        public BoxFile.Info getFile() {
            return this.file;
        }

        /**
         * @return the time that this file version retention was created.
         */
        public Date getAppliedAt() {
            return this.appliedAt;
        }

        /**
         * @return the time that the retention period expires on this file version retention.
         */
        public Date getDispositionAt() {
            return this.dispositionAt;
        }

        /**
         * @return the winning retention policy applied to this file version retention.
         */
        public BoxRetentionPolicy.Info getWinningPolicy() {
            return this.winningPolicy;
        }

        /**
         * {@inheritDoc}
         */
        @Override
        void parseJSONMember(JsonObject.Member member) {
            super.parseJSONMember(member);
            String memberName = member.getName();
            JsonValue value = member.getValue();
            try {
                if (memberName.equals("winning_retention_policy")) {
                    JsonObject policyJSON = value.asObject();
                    if (this.winningPolicy == null) {
                        String policyID = policyJSON.get("id").asString();
                        BoxRetentionPolicy policy = new BoxRetentionPolicy(getAPI(), policyID);
                        this.winningPolicy = policy.new Info(policyJSON);
                    } else {
                        this.winningPolicy.update(policyJSON);
                    }
                } else if (memberName.equals("file")) {
                    JsonObject fileJSON = value.asObject();
                    if (this.file == null) {
                        String fileID = fileJSON.get("id").asString();
                        BoxFile file = new BoxFile(getAPI(), fileID);
                        this.file = file.new Info(fileJSON);
                    } else {
                        this.file.update(fileJSON);
                    }
                } else if (memberName.equals("file_version")) {
                    JsonObject versionJSON = value.asObject();
                    String fileVersionID = versionJSON.get("id").asString();
                    this.fileVersion = new BoxFileVersion(getAPI(), versionJSON, fileVersionID);
                } else if (memberName.equals("applied_at")) {
                    this.appliedAt = BoxDateFormat.parse(value.asString());
                } else if (memberName.equals("disposition_at")) {
                    this.dispositionAt = BoxDateFormat.parse(value.asString());
                }
            } catch (ParseException e) {
                assert false : "A ParseException indicates a bug in the SDK.";
            }
        }
    }

    /**
     * Represents possible query filters for "Get File Version Retentions" function.
     */
    public static class QueryFilter extends QueryStringBuilder {

        /**
         * Param name for the file id to filter the file version retentions by.
         */
        private static final String PARAM_FILE_ID = "file_id";

        /**
         * Param name for the file version id to filter the file version retentions by.
         */
        private static final String PARAM_FILE_VERSION_ID = "file_version_id";

        /**
         * Param name for the policy id to filter the file version retentions by.
         */
        private static final String PARAM_POLICY_ID = "policy_id";

        /**
         * Param name for the disposition action of the retention policy.
         */
        private static final String PARAM_DISPOSITION_ACTION = "disposition_action";

        /**
         * Param name for the datetime to filter file version retentions.
         */
        private static final String PARAM_DISPOSITION_BEFORE = "disposition_before";

        /**
         * Param name for the datetime to filter file version retentions.
         */
        private static final String PARAM_DISPOSITION_AFTER = "disposition_after";

        /**
         * Param name for the the fields to retrieve.
         */
        private static final String PARAM_FIELDS = "fields";

        /**
         * Constructs empty query filter.
         */
        public QueryFilter() {
            super();
        }

        /**
         * @param id a file id to filter the file version retentions by.
         * @return modified query filter.
         */
        public QueryFilter addFileID(String id) {
            this.appendParam(PARAM_FILE_ID, id);
            return this;
        }

        /**
         * @param id a file version id to filter the file version retentions by.
         * @return modified query filter.
         */
        public QueryFilter addFileVersionID(String id) {
            this.appendParam(PARAM_FILE_VERSION_ID, id);
            return this;
        }

        /**
         * @param id a policy id to filter the file version retentions by.
         * @return modified query filter.
         */
        public QueryFilter addPolicyID(String id) {
            this.appendParam(PARAM_POLICY_ID, id);
            return this;
        }

        /**
         * The action can be "permanently_delete" or "remove_retention".
         * @param action the disposition action of the retention policy.
         * @return modified query filter.
         */
        public QueryFilter addDispositionAction(String action) {
            this.appendParam(PARAM_DISPOSITION_ACTION, action);
            return this;
        }

        /**
         * @param date the datetime to filter file version retentions.
         * @return modified query filter.
         */
        public QueryFilter addDispositionBefore(Date date) {
            this.appendParam(PARAM_DISPOSITION_BEFORE, BoxDateFormat.format(date));
            return this;
        }

        /**
         * @param date the datetime to filter file version retentions.
         * @return modified query filter.
         */
        public QueryFilter addDispositionAfter(Date date) {
            this.appendParam(PARAM_DISPOSITION_AFTER, BoxDateFormat.format(date));
            return this;
        }

        /**
         * @param fields the fields to retrieve.
         * @return modified query filter.
         */
        public QueryFilter addFields(String ... fields) {
            if (fields.length > 0) {
                this.appendParam(PARAM_FIELDS, fields);
            }
            return this;
        }
    }
}