cordelia-taryne/src/modules/alt.ts

/**
 * @copyright nhcarrigan
 * @license Naomi's Public License
 * @author Naomi Carrigan
 */
import { MessageFlags, type ChatInputCommandInteraction } from "discord.js";
import { personality } from "../config/personality.js";
import { ai } from "../utils/ai.js";
import { calculateCost } from "../utils/calculateCost.js";
import { isSubscribed } from "../utils/isSubscribed.js";
import { logger } from "../utils/logger.js";
import { replyToError } from "../utils/replyToError.js";
import type { Base64ImageSource } from "@anthropic-ai/sdk/resources/index.js";

const isValidContentType = (
  type: string,
): type is Base64ImageSource["media_type"] => {
  return [
    "image/jpg",
    "image/jpeg",
    "image/png",
    "image/gif",
    "image/webp",
  ].includes(type);
};

/**
 * Validates the attachment is an image in the correct format, then downloads
 * it and sends it to Claude to generate alt-text.
 * @param interaction -- The interaction payload from Discord.
 */
// eslint-disable-next-line max-lines-per-function, complexity, max-statements -- This function is large but necessary.
export const alt = async(
  interaction: ChatInputCommandInteraction,
): Promise<void> => {
  try {
    await interaction.deferReply({ flags: [ MessageFlags.Ephemeral ] });
    const sub = await isSubscribed(interaction);
    if (!sub) {
      return;
    }

    const image = interaction.options.getAttachment("image", true);
    const { contentType, height, width, size, url } = image;

    // Claude supports JPG, PNG, GIF, WEBP
    if (
      contentType === null
    || !isValidContentType(contentType)
    || height === null
    || width === null
    ) {
      await interaction.editReply({
        content: "That does not appear to be a valid image.",
      });
      return;
    }

    // Max file size is 5MB
    if (size > 5 * 1024 * 1024) {
      await interaction.editReply({
        content:
        // eslint-disable-next-line stylistic/max-len -- It's a long string.
        "That image is too large. Please provide an image that is less than 5MB.",
      });
      return;
    }

    // Max dimensions are 8000px
    if (height > 8000 || width > 8000) {
      await interaction.editReply({
        content:
        // eslint-disable-next-line stylistic/max-len -- It's a long string.
        "That image is too large. Please provide an image that is less than 8000 pixels high or wide.",
      });
      return;
    }

    const downloadRequest = await fetch(url);

    const blob = await downloadRequest.arrayBuffer();
    const base64 = Buffer.from(blob).toString("base64");

    const messages = await ai.messages.create({
    // eslint-disable-next-line @typescript-eslint/naming-convention -- Required key format for SDK.
      max_tokens: 2000,
      messages:   [
        {
          content: [
            {
              source: {
                data:       base64,
                // eslint-disable-next-line @typescript-eslint/naming-convention -- Required property syntax for SDK.
                media_type: contentType,
                type:       "base64",
              },
              type: "image",
            },
          ],
          role: "user",
        },
      ],
      model:       "claude-sonnet-4-20250514",
      system:      `${personality} Your role in this conversation is to generate descriptive and accessible alt-text for the user's image. Be as descriptive as possible. Do not include ANYTHING in your response EXCEPT the actual alt-text. Wrap the text in a multi-line code block for easy copying.`,
      temperature: 1,
    });

    const response = messages.content.find((message) => {
      return message.type === "text";
    });

    await interaction.editReply(
      response?.text
      ?? "I'm sorry, I don't have an answer for that. Please try again later.",
    );

    const { usage } = messages;
    await calculateCost(usage, interaction.user.username, "alt-text");
  } catch (error) {
    await replyToError(interaction);
    if (error instanceof Error) {
      await logger.error("alt-text command", error);
    }
  }
};