import type {
  ModeratorContext,
  RoleResult,
  StartStep,
  WorkflowDefinition,
  WorkflowMessage,
} from "@uncaged/nerve-core";
import { END } from "@uncaged/nerve-core";

type WorkflowMeta = {
  greeter: {
    name: string;
    error: string | null;
  };
};

const DEFAULT_NAME = "friend";

function resolveNameFromContent(content: string): { name: string; error: string | null } {
  const trimmed = content.trim();
  if (trimmed === "") {
    return { name: DEFAULT_NAME, error: "empty_input" };
  }

  let jsonParsed: unknown;
  let parseOk: boolean;
  try {
    jsonParsed = JSON.parse(trimmed);
    parseOk = true;
  } catch {
    parseOk = false;
  }

  if (parseOk) {
    if (jsonParsed !== null && typeof jsonParsed === "object" && !Array.isArray(jsonParsed)) {
      const nameField = (jsonParsed as Record<string, unknown>).name;
      if (typeof nameField === "string") {
        const n = nameField.trim();
        if (n !== "") {
          return { name: n, error: null };
        }
        return { name: DEFAULT_NAME, error: "name_empty" };
      }
      return { name: DEFAULT_NAME, error: "missing_name" };
    }
    return { name: DEFAULT_NAME, error: "invalid_json_shape" };
  }

  return { name: trimmed, error: null };
}

async function greeter(
  start: StartStep,
  _messages: WorkflowMessage[],
): Promise<RoleResult<WorkflowMeta["greeter"]>> {
  try {
    const { name, error } = resolveNameFromContent(start.content);
    return {
      content: `Hello, ${name}!`,
      meta: { name, error },
    };
  } catch (unhandled) {
    const msg = unhandled instanceof Error ? unhandled.message : String(unhandled);
    return {
      content: `Hello, ${DEFAULT_NAME}!`,
      meta: { name: DEFAULT_NAME, error: `internal_error: ${msg}` },
    };
  }
}

const workflow: WorkflowDefinition<WorkflowMeta> = {
  name: "hello-world",
  roles: { greeter },
  moderator(context: ModeratorContext<WorkflowMeta>) {
    if (context.steps.length === 0) {
      return "greeter";
    }
    const last = context.steps[context.steps.length - 1];
    if (last.role === "greeter") {
      return END;
    }
    return END;
  },
};

export default workflow;