import { pipe, each, cmd, assignMeta, glob, read, branchGen, type PipelineOp } from "./task.ts";

/**
 * Extracts the channel ID from the filename, e.g.
 * "GuildName - Text Channels - ChannelName [0000000000000000].json" → "0000000000000000"
 */
function chatExporterChannelId(t: { path: string }): string {
  const match = t.path.match(/\[([^\]]+)\]\.json$/);
  return match?.[1] ?? t.path.split('/').pop()!;
}

/**
 * Channel metadata aggregate + messages table, one pair per exported JSON file.
 * Unlike the native Discord export, DiscordChatExporter captures ALL authors' messages.
 */
function discord_chat_exporter_messages(): PipelineOp {
  return branchGen(function* () {
    // Channel-level metadata aggregated into a single table
    yield pipe(
      glob(`*.json`),
      assignMeta({ idValue: t => `DiscordCE - Channel ${chatExporterChannelId(t)}` }),
      read(),
      each(t => t.clone().cmd(["jq", "-r", `
        ["${t.id}", .guild.name, .channel.name, .channel.type, (.channel.category // ""), (.channel.topic // ""), .messageCount]
        | @csv
      `])),
      assignMeta({
        aggregate: true,
        aggregateColumns: ["id", "guild_name", "channel_name", "channel_type", "channel_category", "channel_topic", "message_count"],
        idValue: "DiscordCE - Messages Meta",
      })
    );

    // The messages — one table per exported file
    yield pipe(
      glob(`*.json`),
      assignMeta({ idValue: t => `DiscordCE - Messages ${chatExporterChannelId(t)}` }),
      read(),
      cmd(["jq", "-r", `
        ["id", "timestamp", "author", "discriminator", "content", "attachment"],
        (
          .messages[]
          | [
              .id,
              .timestamp,
              .author.name,
              (.author.discriminator // ""),
              .content,
              (.attachments[0].url // "")
            ]
        )
        | @csv
      `]),
      assignMeta({
        metaIdValue: "DiscordCE - Messages Meta",
        columnMeta: ["any", "isodatetime", "sender", "any", "text", "url"],
        perRowDescription: '"{4}" from {2} at {1}',
        perRowTags: "discord,message",
      })
    );
  });
}

export function discord_chat_exporter(): PipelineOp {
  return pipe(
    assignMeta({ idValue: t => `DiscordCE - ${t.basename}` }),
    discord_chat_exporter_messages()
  );
}