import {
  createInterface,
  type Interface as ReadlineInterface,
} from "node:readline/promises";

import type { Extension } from "../../kernel";
import { Event, ExtensionId, Hook } from "../catalog";
import type { AgentService } from "../shared/agent";
import type { WorkspaceService } from "../shared/workspace";
import { parseInput } from "./input";

export function createCliExtension(): Extension {
  let terminal: ReadlineInterface | undefined;
  let loop: Promise<void> | undefined;
  let currentRequest: AbortController | undefined;

  return {
    setup() {},

    start(context) {
      const agent = context.get<AgentService>(Hook.Agent);
      const workspace = context.get<WorkspaceService>(Hook.Workspace);
      const roleNames = {
        user: "用户",
        assistant: "助手",
        system: "系统",
      };
      terminal = createInterface({
        input: process.stdin,
        output: process.stdout,
      });

      terminal.on("SIGINT", () => {
        if (currentRequest) {
          currentRequest.abort();
        } else {
          terminal?.close();
        }
      });

      loop = (async () => {
        try {
          process.stdout.write(
            `llm-to-agent\nWorkspace: ${process.cwd()}\n当前对话: ${workspace.conversationId}\n命令: /new、/switch <id>、/history、/exit，Ctrl+C 取消当前回复。\n\n`,
          );
          terminal?.setPrompt("> ");
          terminal?.prompt();

          for await (const line of terminal!) {
            const input = parseInput(line);

            if (!input) {
              terminal?.prompt();
              continue;
            }

            if (input.type === "command") {
              if (input.name === "exit") break;

              if (input.name === "new") {
                const conversationId = await workspace.newConversation();
                process.stdout.write(`已新建对话: ${conversationId}\n\n`);
              } else if (input.name === "switch") {
                if (!input.argument) {
                  process.stdout.write("用法: /switch <conversation-id>\n\n");
                } else if (await workspace.switchConversation(input.argument)) {
                  process.stdout.write(`已切换到对话: ${workspace.conversationId}\n\n`);
                } else {
                  process.stdout.write(`对话不存在: ${input.argument}\n\n`);
                }
              } else if (input.name === "history") {
                const messages = await workspace.messages();

                if (messages.length === 0) {
                  process.stdout.write("当前对话暂无消息。\n\n");
                } else {
                  process.stdout.write(`对话 ${workspace.conversationId}\n`);
                  for (const message of messages) {
                    process.stdout.write(
                      `${roleNames[message.role]}: ${message.content}\n`,
                    );
                  }
                  process.stdout.write("\n");
                }
              } else {
                process.stdout.write(`未知命令: /${input.name}\n\n`);
              }

              terminal?.prompt();
              continue;
            }

            currentRequest = new AbortController();

            try {
              for await (const chunk of agent.chat(input.content, currentRequest.signal)) {
                process.stdout.write(chunk);
              }
              process.stdout.write("\n\n");
            } catch (error) {
              if (currentRequest.signal.aborted) {
                process.stdout.write("\n[已取消]\n\n");
              } else {
                process.stderr.write(`\n${String(error)}\n\n`);
              }
            } finally {
              currentRequest = undefined;
            }

            terminal?.prompt();
          }
        } finally {
          terminal?.close();
          await context.emit(Event.RuntimeStopRequested, { source: "cli" });
        }
      })();
    },

    async stop() {
      currentRequest?.abort();
      terminal?.close();
      await loop;
    },
  };
}

createCliExtension.id = ExtensionId.Cli;