import type { Role, RoleResult, StartStep, WorkflowMessage } from "@uncaged/nerve-core";
import type { LlmProvider } from "@uncaged/nerve-workflow-utils";
import { createCursorRole } from "@uncaged/nerve-workflow-utils";
import { z } from "zod";
import { resolveRepoCwd } from "../../lib/repo-context.js";
import { buildImplementPrompt } from "./prompt.js";

export const implementMetaSchema = z.object({
  done: z.boolean().describe("true when changes are complete and build passes this round"),
});
export type ImplementMeta = z.infer<typeof implementMetaSchema>;

export type BuildImplementDeps = {
  provider: LlmProvider;
  nerveRoot: string;
};

export function buildImplementRole({ provider, nerveRoot }: BuildImplementDeps): Role<ImplementMeta> {
  return async (start: StartStep, messages: WorkflowMessage[]): Promise<RoleResult<ImplementMeta>> => {
    const cwd = resolveRepoCwd(messages);
    if (cwd === null) {
      return {
        content: "implement cannot run: missing repo path in thread markers",
        meta: { done: false },
      };
    }

    const runRole = createCursorRole<ImplementMeta>({
      cwd,
      mode: "default",
      model: "auto",
      env: {},
      timeoutMs: 300_000,
      prompt: async () =>
        buildImplementPrompt({
          threadId: (start.meta as { threadId?: string }).threadId ?? "unknown",
          nerveRoot,
        }),
      extract: { provider, schema: implementMetaSchema },
    });

    try {
      return await runRole(start, messages);
    } catch (e) {
      const msg = e instanceof Error ? e.message : String(e);
      return {
        content: `implement failed: ${msg}`,
        meta: { done: false },
      };
    }
  };
}