Add ask command (#205)

* Add slash and prefix commands

* Add command cooldown

* Repeat question in slash commands because it's hard to see

* Sanitize outgoing text

* Make cooldown response ephemeral

* Add option to use imperial measurements

* Make cooldown timer relative

* Missed a 'new'

* Use choice between imperial and metric instead of bool

src/commands/ask.ts

@@ -0,0 +1,139 @@
+import { ApplicationCommandOptionType, CommandInteraction, InteractionResponse, escapeMarkdown } from 'discord.js'
+import {
+  Discord,
+  SimpleCommand,
+  SimpleCommandMessage,
+  SimpleCommandOption,
+  SimpleCommandOptionType,
+  Slash,
+  SlashChoice,
+  SlashOption,
+} from 'discordx'
+
+const COMMAND_NAME = 'ask'
+const COMMAND_DESC = 'Ask a question to Wolfram Alpha'
+
+const COOLDOWN_MILLISECONDS = 3 * 60 * 1000
+
+@Discord()
+class Ask {
+  private apiToken: string
+  private lastUsage: number
+
+  constructor() {
+    this.apiToken = process.env.WOLFRAM_APP_ID ?? ''
+    this.lastUsage = 0
+
+    if (this.apiToken == '') {
+      throw new Error('WOLFRAM_APP_ID needs to be set')
+    }
+  }
+
+  @SimpleCommand({ name: COMMAND_NAME, description: COMMAND_DESC, argSplitter: '\n' })
+  async simple(
+    @SimpleCommandOption({ name: 'question', type: SimpleCommandOptionType.String })
+    question: string | undefined,
+    @SimpleCommandOption({ name: 'units of measurement', type: SimpleCommandOptionType.Boolean })
+    units: string | undefined,
+    command: SimpleCommandMessage
+  ) {
+    if (!question) {
+      return await command.message.reply({
+        content: 'Usage: >ask <question>\n<units?> (metric or imperial)',
+        allowedMentions: { repliedUser: false },
+      })
+    }
+
+    if (this.isOnCooldown()) {
+      return
+    }
+
+    try {
+      const answer = await this.fetchAnswer(question, units)
+      return command.message.reply({ content: answer, allowedMentions: { repliedUser: false } })
+    } catch (err) {
+      console.error(err)
+      return command.message.reply({
+        content: 'There was a problem communicating with Wolfram Alpha.',
+        allowedMentions: { repliedUser: false },
+      })
+    }
+  }
+
+  @Slash({ name: COMMAND_NAME, description: COMMAND_DESC })
+  private async slash(
+    @SlashOption({
+      name: 'question',
+      type: ApplicationCommandOptionType.String,
+      description: 'The question you want to ask',
+      required: true,
+    })
+    question: string,
+    @SlashChoice({ name: 'Metric', value: 'metric' })
+    @SlashChoice({ name: 'Imperial', value: 'imperial' })
+    @SlashOption({
+      name: 'units_of_measurement',
+      description: 'Which units of measurements you want to use',
+      type: ApplicationCommandOptionType.String,
+      required: false,
+    })
+    units: string,
+    interaction: CommandInteraction
+  ): Promise<InteractionResponse<boolean>> {
+    const cooldownMessage = this.isOnCooldown()
+    if (cooldownMessage) {
+      return interaction.reply({ content: cooldownMessage, ephemeral: true })
+    }
+
+    try {
+      const answer = await this.fetchAnswer(question, units)
+      return interaction.reply(`[${escapeMarkdown(question)}] ${answer}`)
+    } catch (err) {
+      console.error(err)
+      return interaction.reply('There was a problem communicating with Wolfram Alpha.')
+    }
+  }
+
+  private async fetchAnswer(question: string, units: string | undefined): Promise<string> {
+    if (units?.toLowerCase() !== 'imperial') {
+      units = 'metric'
+    }
+
+    const url = new URL('https://api.wolframalpha.com/v1/result')
+    url.searchParams.append('appid', this.apiToken)
+    url.searchParams.append('i', question)
+    url.searchParams.append('units', units.toLowerCase())
+
+    console.log(url)
+
+    const response = await fetch(url)
+
+    if (response.ok) {
+      return escapeMarkdown(await response.text())
+    }
+
+    switch (response.status) {
+      case 501: {
+        return 'The bot was not able to answer.'
+      }
+      case 400: {
+        return 'Something was wrong with that input. Did Tip try to break bot again?'
+      }
+      default: {
+        throw new Error(`Something went wrong while asking Wolfram Alpha a question. Status Code: ${response.status}`)
+      }
+    }
+  }
+
+  private isOnCooldown(): string | null {
+    const now = Date.now()
+    const cooldownEnd = this.lastUsage + COOLDOWN_MILLISECONDS
+
+    if (cooldownEnd > now) {
+      return `Command will be off cooldown <t:${Math.floor(cooldownEnd / 1000)}:R>.`
+    }
+
+    this.lastUsage = now
+    return null
+  }
+}