import * as cache from "@actions/cache";
import * as core from "@actions/core";
import { hashFiles } from "../hash/hash-files";
import {
  cacheDependencyGlob,
  cacheLocalPath,
  cachePython,
  cacheSuffix,
  pruneCache,
  pythonDir,
  restoreCache as shouldRestoreCache,
} from "../utils/inputs";
import { getArch, getOSNameVersion, getPlatform } from "../utils/platforms";

export const STATE_CACHE_KEY = "cache-key";
export const STATE_CACHE_MATCHED_KEY = "cache-matched-key";
export const STATE_PYTHON_CACHE_MATCHED_KEY = "python-cache-matched-key";

const CACHE_VERSION = "2";

export async function restoreCache(pythonVersion?: string): Promise<void> {
  const cacheKey = await computeKeys(pythonVersion);
  core.saveState(STATE_CACHE_KEY, cacheKey);
  core.setOutput("cache-key", cacheKey);

  if (!shouldRestoreCache) {
    core.info("restore-cache is false. Skipping restore cache step.");
    core.setOutput("python-cache-hit", false);
    return;
  }

  if (cacheLocalPath === undefined) {
    throw new Error(
      "cache-local-path is not set. Cannot restore cache without a valid cache path.",
    );
  }

  await restoreCacheFromKey(
    cacheKey,
    cacheLocalPath.path,
    STATE_CACHE_MATCHED_KEY,
    "cache-hit",
  );

  if (cachePython) {
    await restoreCacheFromKey(
      `${cacheKey}-python`,
      pythonDir,
      STATE_PYTHON_CACHE_MATCHED_KEY,
      "python-cache-hit",
    );
  } else {
    core.setOutput("python-cache-hit", false);
  }
}

async function restoreCacheFromKey(
  cacheKey: string,
  cachePath: string,
  stateKey: string,
  outputKey: string,
): Promise<void> {
  core.info(
    `Trying to restore cache from GitHub Actions cache with key: ${cacheKey}`,
  );
  let matchedKey: string | undefined;
  try {
    matchedKey = await cache.restoreCache([cachePath], cacheKey);
  } catch (err) {
    const message = (err as Error).message;
    core.warning(message);
    core.setOutput(outputKey, false);
    return;
  }

  handleMatchResult(matchedKey, cacheKey, stateKey, outputKey);
}

async function computeKeys(pythonVersion?: string): Promise<string> {
  let cacheDependencyPathHash = "-";
  if (cacheDependencyGlob !== "") {
    core.info(
      `Searching files using cache dependency glob: ${cacheDependencyGlob.split("\n").join(",")}`,
    );
    cacheDependencyPathHash += await hashFiles(cacheDependencyGlob, true);
    if (cacheDependencyPathHash === "-") {
      core.warning(
        `No file matched to [${cacheDependencyGlob.split("\n").join(",")}]. The cache will never get invalidated. Make sure you have checked out the target repository and configured the cache-dependency-glob input correctly.`,
      );
    }
  }
  if (cacheDependencyPathHash === "-") {
    cacheDependencyPathHash = "-no-dependency-glob";
  }
  const suffix = cacheSuffix ? `-${cacheSuffix}` : "";
  const version = pythonVersion ?? "unknown";
  const platform = await getPlatform();
  const osNameVersion = getOSNameVersion();
  const pruned = pruneCache ? "-pruned" : "";
  const python = cachePython ? "-py" : "";
  return `setup-uv-${CACHE_VERSION}-${getArch()}-${platform}-${osNameVersion}-${version}${pruned}${python}${cacheDependencyPathHash}${suffix}`;
}

function handleMatchResult(
  matchedKey: string | undefined,
  primaryKey: string,
  stateKey: string,
  outputKey: string,
): void {
  if (!matchedKey) {
    core.info(`No GitHub Actions cache found for key: ${primaryKey}`);
    core.setOutput(outputKey, false);
    return;
  }

  core.saveState(stateKey, matchedKey);
  core.info(`cache restored from GitHub Actions cache with key: ${matchedKey}`);
  core.setOutput(outputKey, true);
}