import type { AgentFn, Role, ThreadContext, WorkflowMessage } from "@uncaged/nerve-core";
import type { LlmExtractorConfig } from "@uncaged/nerve-workflow-utils";
import { createRole } from "@uncaged/nerve-workflow-utils";
import { z } from "zod";

import { resolveWorkdir } from "../lib/workdir.js";

import type { AnswererMeta } from "./answerer.js";
import type { QuestionerMeta } from "./questioner.js";

export const explorerMetaSchema = z.object({
  patches: z.array(
    z.object({
      card: z.string(),
      section: z.string(),
    }),
  ),
  new_cards: z.array(z.string()),
});

export type ExplorerMeta = z.infer<typeof explorerMetaSchema>;

export type CreateExplorerRoleDeps = {
  extract: LlmExtractorConfig;
};

function lastMeta<M>(messages: WorkflowMessage[], role: string): M | undefined {
  for (let i = messages.length - 1; i >= 0; i--) {
    if (messages[i].role === role) {
      return messages[i].meta as M;
    }
  }
  return undefined;
}

export function explorerPrompt(ctx: ThreadContext): string {
  const messages = ctx.steps as unknown as WorkflowMessage[];
  const threadId = ctx.start.meta.threadId;
  const qm = lastMeta<QuestionerMeta>(messages, "questioner");
  const am = lastMeta<AnswererMeta>(messages, "answerer");
  const cwd = resolveWorkdir(ctx.start);

  const unanswered =
    am?.results.filter((r) => !r.found).map((r) => r.id) ?? [];

  return `You are the **explorer** in a knowledge-extraction workflow.

## Context

- Thread: \`nerve thread ${threadId}\`
- Working directory (repo root for paths): ${cwd}
- Current knowledge card (questioner): ${qm?.card ?? "(unknown)"}

## Unanswered question ids

${JSON.stringify(unanswered)}

Use the prior answerer results in the thread to map ids to full question text when you read messages above.

## Task

For each unanswered question, **read the codebase** as needed, then either:

- Add a new markdown file under \`.knowledge/\`, or
- Patch an existing card (prefer updating the card listed above when appropriate).

After any write or patch to \`.knowledge\`, run:

\`\`\`bash
nerve knowledge sync
\`\`\`

from this repo root (${cwd}), and fix failures until sync succeeds.

## Output meta

Report \`patches\` as { card, section } entries for cards you edited (section is a short heading or path hint).
Report \`new_cards\` as repo-relative paths for brand-new files you created (e.g. \`.knowledge/new-topic.md\`).

Do not claim work you did not perform.`;
}

export function createExplorerRole(
  adapter: AgentFn,
  { extract }: CreateExplorerRoleDeps,
): Role<ExplorerMeta> {
  return createRole(
    adapter,
    async (ctx: ThreadContext) => explorerPrompt(ctx),
    explorerMetaSchema,
    extract,
  );
}