import type { Role, RoleResult, StartStep, WorkflowMessage } from "@uncaged/nerve-core";
import { cursorAgent, isDryRun, llmExtract } from "@uncaged/nerve-workflow-utils";
import type { LlmProvider } from "@uncaged/nerve-workflow-utils";
import { z } from "zod";
import { resolveRepoCwd } from "../../lib/repo-context.js";
import { threadIdFromStart } from "../../lib/start-meta.js";
import { formatSpawnFailure } from "../../lib/spawn-utils.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 dry = isDryRun(start);
    const prompt = buildImplementPrompt({ threadId: threadIdFromStart(start), nerveRoot });
    const run = await cursorAgent({
      prompt,
      mode: "default",
      model: "auto",
      cwd,
      env: null,
      timeoutMs: 300_000,
      dryRun: dry,
    });

    if (!run.ok) {
      return {
        content: `implement cursor-agent failed: ${formatSpawnFailure(run.error)}`,
        meta: { done: false },
      };
    }

    const metaR = await llmExtract({
      text: run.value,
      schema: implementMetaSchema,
      provider,
      dryRun: dry,
    });
    if (!metaR.ok) {
      return {
        content: `${run.value}\n\n[meta extract failed]`,
        meta: { done: false },
      };
    }

    return { content: run.value, meta: metaR.value };
  };
}