Utilities for JDA discord bots created with the kotlin programming language

KotlinMessageUtils.kt

package com.github.johnnyjayjay.titanbot.utils

import net.dv8tion.jda.core.EmbedBuilder
import net.dv8tion.jda.core.MessageBuilder
import net.dv8tion.jda.core.entities.Message
import net.dv8tion.jda.core.entities.MessageEmbed
import net.dv8tion.jda.core.entities.MessageEmbed.*
import java.awt.Color
import java.time.Instant
import java.time.temporal.TemporalAccessor
import java.util.*

const val ZERO_WIDTH_SPACE = EmbedBuilder.ZERO_WIDTH_SPACE

fun messages(vararg policy: MessageBuilder.SplitPolicy, body: KotlinMessageBuilder.() -> Unit) = 
    KotlinMessageBuilder().buildAll(policy = *policy, body = body)

fun message(body: KotlinMessageBuilder.() -> Unit) = KotlinMessageBuilder().build(body)

fun embed(body: KotlinEmbedBuilder.() -> Unit) = KotlinEmbedBuilder().build(body)

fun fields(body: Fields.() -> Unit) = Fields().apply(body)

fun field(body: FieldBuilder.() -> Unit) = FieldBuilder().build(body)

class KotlinMessageBuilder {
    lateinit var content: String
    var embed: MessageEmbed? = null
    var tts: Boolean = false

    fun build(body: KotlinMessageBuilder.() -> Unit): Message {
        body()
        return build()
    }
    
    fun buildAll(vararg policy: MessageBuilder.SplitPolicy, body: KotlinMessageBuilder.() -> Unit): Queue<Message> {
        body()
        return buildAll(*policy)
    }

    fun build() = makeBuilder().build()

    fun buildAll(vararg policy: MessageBuilder.SplitPolicy) =
        makeBuilder().buildAll(*policy)

    private fun makeBuilder() =
        MessageBuilder()
        .setContent(content)
        .setEmbed(embed)
        .setTTS(tts)
}

class KotlinEmbedBuilder {
    lateinit var description: String
    var thumbnail: String? = null
    var image: String? = null
    var title: String? = null
    var avatar: String? = null
    var author: String? = null
    var authorURL: String? = null
    var titleURL: String? = null
    var footer: String? = null
    var icon: String? = null
    var timestamp: TemporalAccessor? = null
    var color: Color? = null
    var fields: Fields = Fields()

    fun build(): MessageEmbed {
        return EmbedBuilder().setDescription(description)
            .setThumbnail(thumbnail)
            .setImage(image)
            .setTitle(title, titleURL)
            .setAuthor(author, authorURL, avatar)
            .setFooter(footer, icon)
            .setTimestamp(timestamp)
            .setColor(color)
            .also {
                for (field in fields)
                    it.addField(field)
            }
            .build()
    }

    fun build(body: KotlinEmbedBuilder.() -> Unit): MessageEmbed {
        body()
        return build()
    }
    
    fun now(): TemporalAccessor = Instant.now()
}

class Fields {
    private val list: MutableList<Field> = ArrayList()

    fun blank(inline: Boolean = false) =
        add(Field(ZERO_WIDTH_SPACE, ZERO_WIDTH_SPACE, inline))

    fun add(field: Field) = list.add(field)

    fun add(body: FieldBuilder.() -> Unit) = add(FieldBuilder().build(body))

    operator fun iterator() = list.iterator()
}

class FieldBuilder {
    lateinit var name: String
    lateinit var value: String
    var inline = false

    fun build() = Field(name, value, inline)

    fun build(body: FieldBuilder.() -> Unit): Field {
        body()
        return build()
    }
}