import { SlashCommandBuilder, PermissionFlagsBits, ModalBuilder, TextInputBuilder, TextInputStyle, ActionRowBuilder } from 'discord.js';
import fs from 'fs';
import path from 'path';
import fetch from 'node-fetch';
// Modal text input limits
const MAX_LEN = 4000;
const MAX_FIELDS = 5;

/**
 * responsesPrompt module
 * Provides a /prompt command to view or update the AI response prompt
 * Stored in PocketBase collection 'responses_prompts' with fields:
 *   clientId (string), prompt (text), updatedBy (string), created/updated timestamps
 */
export const commands = [
  {
    data: new SlashCommandBuilder()
      .setName('prompt')
      .setDescription('View or update the AI response prompt')
      .setDefaultMemberPermissions(PermissionFlagsBits.Administrator)
      .setDMPermission(false)
      .addStringOption(opt =>
        opt.setName('url')
          .setDescription('URL to a .txt file containing the prompt')
          .setRequired(false)
      ),
    async execute(interaction, client) {
      const url = interaction.options.getString('url');
      const clientId = client.config.id;
      // URL-based update
      if (url) {
        client.logger.info(`[cmd:prompt] URL update requested for client ${clientId}: ${url}`);
        await interaction.deferReply({ ephemeral: true });
        if (!url.toLowerCase().endsWith('.txt')) {
          client.logger.warn(`[cmd:prompt] Invalid URL extension, must end .txt: ${url}`);
          return interaction.editReply({ content: 'URL must point to a .txt file.', ephemeral: true });
        }
        try {
          const res = await fetch(url);
          if (!res.ok) throw new Error(`HTTP ${res.status}`);
          const text = await res.text();
          // Upsert into PocketBase
          const existing = await client.pb.getFirst('responses_prompts', `clientId="${clientId}"`);
          const recId = existing?.id;
          await client.pb.upsert('responses_prompts', recId, {
            clientId,
            prompt: text,
            updatedBy: interaction.user.id
          });
          client.responsesPrompt = text;
          return interaction.editReply({ content: 'Prompt updated from URL.', ephemeral: true });
        } catch (err) {
          client.logger.error(`[cmd:prompt] URL update failed: ${err.message}`);
          return interaction.editReply({ content: `Error fetching URL: ${err.message}`, ephemeral: true });
        }
      }
      // Modal-based edit
      const existingPrompt = client.responsesPrompt || '';
      // Prevent modal if prompt exceeds capacity
      if (existingPrompt.length > MAX_LEN * MAX_FIELDS) {
        return interaction.reply({
          content: 'Current prompt too large for modal editing (exceeds 20000 chars); please use URL.',
          ephemeral: true
        });
      }
      // Prepare chunks
      const chunks = [];
      for (let offset = 0; offset < existingPrompt.length; offset += MAX_LEN) {
        chunks.push(existingPrompt.slice(offset, offset + MAX_LEN));
      }
      // Build modal
      const modal = new ModalBuilder()
        .setCustomId(`promptModal-${clientId}`)
        .setTitle('Edit AI Prompt');
      // Add text inputs for existing chunks
      chunks.forEach((chunk, idx) => {
        const input = new TextInputBuilder()
          .setCustomId(`prompt_${idx}`)
          .setLabel(`Part ${idx + 1}`)
          .setStyle(TextInputStyle.Paragraph)
          .setRequired(idx === 0)
          .setMaxLength(MAX_LEN)
          .setValue(chunk);
        modal.addComponents(new ActionRowBuilder().addComponents(input));
      });
      // Add one extra empty field to allow expansion (up to MAX_FIELDS)
      if (chunks.length < MAX_FIELDS) {
        const i = chunks.length;
        const input = new TextInputBuilder()
          .setCustomId(`prompt_${i}`)
          .setLabel(`Part ${i + 1}`)
          .setStyle(TextInputStyle.Paragraph)
          .setRequired(false)
          .setMaxLength(MAX_LEN);
        modal.addComponents(new ActionRowBuilder().addComponents(input));
      }
      client.logger.info(`[cmd:prompt] Showing modal editor for client ${clientId} with ${chunks.length} parts`);
      await interaction.showModal(modal);
    }
  }
];

/** track clients for modal handling */
const _clients = [];

/**
 * init hook: load existing prompt and register modal submit handler
 */
export async function init(client, clientConfig) {
  client.logger.info('[module:responsesPrompt] Module loaded');
  const clientId = clientConfig.id;
  // Load prompt from PocketBase or fallback to file
  let prompt = '';
  try {
    const record = await client.pb.getFirst('responses_prompts', `clientId="${clientId}"`);
    if (record && record.prompt) {
      prompt = record.prompt;
    } else if (clientConfig.responses?.systemPromptPath) {
      const filePath = path.isAbsolute(clientConfig.responses.systemPromptPath)
        ? clientConfig.responses.systemPromptPath
        : path.join(process.cwd(), clientConfig.responses.systemPromptPath);
      prompt = fs.readFileSync(filePath, 'utf8');
    }
  } catch (err) {
    client.logger.error(`responsesPrompt init error: ${err.message}`);
  }
  client.responsesPrompt = prompt;
  _clients.push({ client, clientConfig });
  // Modal submit listener
  client.on('interactionCreate', async interaction => {
    if (!interaction.isModalSubmit()) return;
    if (interaction.customId !== `promptModal-${clientId}`) return;
    // Reassemble prompt from modal fields, inserting line breaks between parts
    client.logger.info(`[cmd:prompt] Modal submission received for client ${clientId}`);
    const parts = [];
    for (let i = 0; i < MAX_FIELDS; i++) {
      try {
        const value = interaction.fields.getTextInputValue(`prompt_${i}`) || '';
        if (value.trim().length > 0) parts.push(value);
      } catch {}
    }
    const newPrompt = parts.join('\n');
    // Save to PocketBase
    try {
      client.logger.debug(`[cmd:prompt] Saving new prompt for client ${clientId}, length=${newPrompt.length}`);
      const existing = await client.pb.getFirst('responses_prompts', `clientId="${clientId}"`);
      const recId = existing?.id;
      await client.pb.upsert('responses_prompts', recId, {
        clientId,
        prompt: newPrompt,
        updatedBy: interaction.user.id
      });
      client.responsesPrompt = newPrompt;
      await interaction.reply({ content: 'Prompt updated!', ephemeral: true });
    } catch (err) {
      client.logger.error(`responsesPrompt modal submit error: ${err.message}`);
      await interaction.reply({ content: `Error saving prompt: ${err.message}`, ephemeral: true });
    }
  });
}