import { normalizeLowercaseStringOrEmpty } from "../shared/string-coerce.js";

type OpenAIReasoningCompatModel = {
  provider?: string | null;
  id?: string | null;
  compat?: unknown;
};

const OPENAI_MEDIUM_ONLY_REASONING_MODEL_IDS = new Set(["gpt-5.1-codex-mini", "gpt-5.4-mini"]);

function readCompatReasoningEffortMap(compat: unknown): Record<string, string> {
  if (!compat || typeof compat !== "object") {
    return {};
  }
  const rawMap = (compat as { reasoningEffortMap?: unknown }).reasoningEffortMap;
  if (!rawMap || typeof rawMap !== "object") {
    return {};
  }
  return Object.fromEntries(
    Object.entries(rawMap).filter(
      (entry): entry is [string, string] =>
        typeof entry[0] === "string" && typeof entry[1] === "string",
    ),
  );
}

export function resolveOpenAIReasoningEffortMap(
  model: OpenAIReasoningCompatModel,
  fallbackMap: Record<string, string> = {},
): Record<string, string> {
  const provider = normalizeLowercaseStringOrEmpty(model.provider ?? "");
  const id = normalizeLowercaseStringOrEmpty(model.id ?? "");
  const builtinMap: Record<string, string> =
    (provider === "openai" || provider === "openai-codex") &&
    OPENAI_MEDIUM_ONLY_REASONING_MODEL_IDS.has(id)
      ? { minimal: "medium", low: "medium" }
      : {};
  return {
    ...fallbackMap,
    ...builtinMap,
    ...readCompatReasoningEffortMap(model.compat),
  };
}

export function mapOpenAIReasoningEffortForModel(params: {
  model: OpenAIReasoningCompatModel;
  effort?: string;
  fallbackMap?: Record<string, string>;
}): string | undefined {
  const { effort } = params;
  if (effort === undefined || effort === "none") {
    return effort;
  }
  const reasoningEffortMap = resolveOpenAIReasoningEffortMap(params.model, params.fallbackMap);
  return reasoningEffortMap[effort] ?? effort;
}