/*
 *   Copyright 2024 Vonage
 *
 *   Licensed under the Apache License, Version 2.0 (the "License");
 *   you may not use this file except in compliance with the License.
 *   You may obtain a copy of the License at
 *
 *        http://www.apache.org/licenses/LICENSE-2.0
 *
 *   Unless required by applicable law or agreed to in writing, software
 *   distributed under the License is distributed on an "AS IS" BASIS,
 *   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *   See the License for the specific language governing permissions and
 *   limitations under the License.
 */
package com.vonage.client.conversations;

import com.fasterxml.jackson.annotation.JsonProperty;
import com.vonage.client.users.channels.Channel;
import com.vonage.client.users.channels.Pstn;
import java.net.URI;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;

/**
 * Represents a Conversation (request and response).
 */
public class Conversation extends BaseConversation {
        private ConversationStatus state;
        private Integer sequenceNumber;
        private ConversationProperties properties;
        private Collection<? extends Channel> numbers;
        private Callback callback;

        protected Conversation() {
        }

        Conversation(Builder builder) {
                if ((name = builder.name) != null && (name.length() > 100 || name.trim().isEmpty())) {
                        throw new IllegalArgumentException("Name must be between 1 and 100 characters.");
                }
                if ((displayName = builder.displayName) != null && (displayName.length() > 50 || displayName.trim().isEmpty())) {
                        throw new IllegalArgumentException("Display name must be between 1 and 50 characters.");
                }
                imageUrl = builder.imageUrl;
                properties = builder.properties;
                callback = builder.callback;
                if ((numbers = builder.numbers) != null) {
                        numbers.forEach(Channel::setTypeField);
                }
        }

        /**
         * The state the conversation is in.
         *
         * @return The conversation state as an enum, or {@code null} if unknown.
         */
        @JsonProperty("state")
        public ConversationStatus getState() {
                return state;
        }

        /**
         * The last Event ID in this conversation. This ID can be used to retrieve a specific event.
         *
         * @return The last event ID as an integer, or {@code null} if unknown.
         */
        @JsonProperty("sequence_number")
        public Integer getSequenceNumber() {
                return sequenceNumber;
        }

        /**
         * Properties for this conversation.
         *
         * @return The conversation properties object, or {@code null} if not applicable.
         */
        @JsonProperty("properties")
        public ConversationProperties getProperties() {
                return properties;
        }

        /**
         * Channels containing the contact numbers for this conversation.
         * Currently, only {@link Pstn} (Phone) type is supported.
         *
         * @return The channels associated with this conversation, or {@code null} if unspecified.
         */
        @JsonProperty("numbers")
        public Collection<? extends Channel> getNumbers() {
                return numbers;
        }

        /**
         * Specifies callback parameters for webhooks.
         *
         * @return The callback properties, or {@code null} if unspecified.
         */
        @JsonProperty("callback")
        public Callback getCallback() {
                return callback;
        }

        /**
         * Entry point for constructing an instance of this class.
         * 
         * @return A new Builder.
         */
        public static Builder builder() {
                return new Builder();
        }

        /**
         * Builder for creating or updating a Conversation. All fields are optional.
         */
        public static class Builder {
                private String name, displayName;
                private URI imageUrl;
                private ConversationProperties properties;
                private Collection<? extends Channel> numbers;
                private Callback callback;
        
                Builder() {}

                /**
                 * Internal conversation name. Must be unique.
                 *
                 * @param name The conversation name.
                 *
                 * @return This builder.
                 */
                public Builder name(String name) {
                        this.name = name;
                        return this;
                }

                /**
                 * The public facing name of the conversation.
                 *
                 * @param displayName The display name.
                 *
                 * @return This builder.
                 */
                public Builder displayName(String displayName) {
                        this.displayName = displayName;
                        return this;
                }

                /**
                 * An image URL that you associate with the conversation.
                 *
                 * @param imageUrl The image URL as a string.
                 *
                 * @return This builder.
                 */
                public Builder imageUrl(String imageUrl) {
                        this.imageUrl = URI.create(imageUrl);
                        return this;
                }

                /**
                 * Properties for this conversation.
                 *
                 * @param properties The conversation properties object.
                 *
                 * @return This builder.
                 */
                public Builder properties(ConversationProperties properties) {
                        this.properties = properties;
                        return this;
                }

                /**
                 * Sets the PSTN numbers for this conversation.
                 *
                 * @param phoneNumber The telephone or mobile number(s) for this conversation in E.164 format.
                 *
                 * @return This builder.
                 */
                public Builder phone(String... phoneNumber) {
                        return numbers(Arrays.stream(phoneNumber).map(Pstn::new).toArray(Channel[]::new));
                }

                /**
                 * Channels containing the contact numbers for this conversation.
                 *
                 * @param numbers The channels associated with this conversation.
                 *
                 * @return This builder.
                 */
                Builder numbers(Channel... numbers) {
                        return numbers(Arrays.asList(numbers));
                }

                /**
                 * Channels containing the contact numbers for this conversation.
                 *
                 * @param numbers The channels associated with this conversation.
                 *
                 * @return This builder.
                 */
                Builder numbers(Collection<? extends Channel> numbers) {
                        this.numbers = new ArrayList<>(numbers);
                        return this;
                }

                /**
                 * Specifies callback parameters for webhooks.
                 *
                 * @param callback The callback properties, or {@code null} if unspecified.
                 *
                 * @return This builder.
                 */
                public Builder callback(Callback callback) {
                        this.callback = callback;
                        return this;
                }

                /**
                 * Builds the {@linkplain Conversation}.
                 *
                 * @return An instance of Conversation, populated with all fields from this builder.
                 */
                public Conversation build() {
                        return new Conversation(this);
                }
        }
}