import * as fs from "fs";
import * as path from "path";

const handler = async (event) => {
  if (event.type !== "agent" || event.action !== "bootstrap") return;

  const cfg = event.context?.cfg;
  const workspaceDir = event.context?.workspaceDir;
  if (!workspaceDir) return;

  // Resolve active model string
  const modelRaw: string =
    (typeof cfg?.agents?.defaults?.model === "string"
      ? cfg.agents.defaults.model
      : cfg?.agents?.defaults?.model?.primary) ?? "";

  const model = modelRaw.toLowerCase();

  // Detect model family by model name (provider-agnostic)
  let family: "anthropic" | "openai" | "generic";
  if (model.includes("claude")) {
    family = "anthropic";
  } else if (model.includes("gpt")) {
    family = "openai";
  } else {
    family = "generic";
  }

  const hintsDir = path.join(
    workspaceDir,
    "skills",
    "llm-tool-best-practices",
    "hints"
  );
  const hintsFile = path.join(hintsDir, `${family}.md`);

  let content: string;
  try {
    content = fs.readFileSync(hintsFile, "utf8");
  } catch {
    // Hints file missing — skip silently
    console.warn(
      `[model-skill-injector] Hints file not found: ${hintsFile} (family=${family}, model=${modelRaw})`
    );
    return;
  }

  // Inject as a virtual bootstrap file
  const bootstrapFiles = event.context?.bootstrapFiles;
  if (!Array.isArray(bootstrapFiles)) return;

  // Remove any previous injection (idempotent on re-runs)
  const existing = bootstrapFiles.findIndex((f) => f.name === "MODEL_HINTS.md");
  if (existing !== -1) bootstrapFiles.splice(existing, 1);

  bootstrapFiles.push({
    name: "MODEL_HINTS.md",
    content,
    // Mark virtual so it doesn't try to read from disk
    virtual: true,
  });

  console.log(
    `[model-skill-injector] Injected ${family} hints (model=${modelRaw})`
  );
};

export default handler;