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

import * as core from "@actions/core";
import * as toolrunner from "@actions/exec/lib/toolrunner";
import * as safeWhich from "@chrisgavin/safe-which";
import { JSONSchemaForNPMPackageJsonFiles } from "@schemastore/package";

import type { Config } from "./config-utils";
import {
  doesDirectoryExist,
  getCodeQLDatabasePath,
  getRequiredEnvParam,
  UserError,
} from "./util";

// eslint-disable-next-line import/no-commonjs
const pkg = require("../package.json") as JSONSchemaForNPMPackageJsonFiles;

/**
 * Wrapper around core.getInput for inputs that always have a value.
 * Also see getOptionalInput.
 *
 * This allows us to get stronger type checking of required/optional inputs.
 */
export const getRequiredInput = function (name: string): string {
  const value = core.getInput(name);
  if (!value) {
    throw new UserError(`Input required and not supplied: ${name}`);
  }
  return value;
};

/**
 * Wrapper around core.getInput that converts empty inputs to undefined.
 * Also see getRequiredInput.
 *
 * This allows us to get stronger type checking of required/optional inputs.
 */
export const getOptionalInput = function (name: string): string | undefined {
  const value = core.getInput(name);
  return value.length > 0 ? value : undefined;
};

export function getTemporaryDirectory(): string {
  const value = process.env["CODEQL_ACTION_TEMP"];
  return value !== undefined && value !== ""
    ? value
    : getRequiredEnvParam("RUNNER_TEMP");
}

/**
 * Gets the SHA of the commit that is currently checked out.
 */
export const getCommitOid = async function (
  checkoutPath: string,
  ref = "HEAD",
): Promise<string> {
  // Try to use git to get the current commit SHA. If that fails then
  // log but otherwise silently fall back to using the SHA from the environment.
  // The only time these two values will differ is during analysis of a PR when
  // the workflow has changed the current commit to the head commit instead of
  // the merge commit, which must mean that git is available.
  // Even if this does go wrong, it's not a huge problem for the alerts to
  // reported on the merge commit.
  let stderr = "";
  try {
    let commitOid = "";
    await new toolrunner.ToolRunner(
      await safeWhich.safeWhich("git"),
      ["rev-parse", ref],
      {
        silent: true,
        listeners: {
          stdout: (data) => {
            commitOid += data.toString();
          },
          stderr: (data) => {
            stderr += data.toString();
          },
        },
        cwd: checkoutPath,
      },
    ).exec();
    return commitOid.trim();
  } catch (e) {
    if (stderr.includes("not a git repository")) {
      core.info(
        "Could not determine current commit SHA using git. Continuing with data from user input or environment. " +
          "The checkout path provided to the action does not appear to be a git repository.",
      );
    } else {
      core.info(
        `Could not determine current commit SHA using git. Continuing with data from user input or environment. ${stderr}`,
      );
    }

    return getOptionalInput("sha") || getRequiredEnvParam("GITHUB_SHA");
  }
};

/**
 * If the action was triggered by a pull request, determine the commit sha of the merge base.
 * Returns undefined if run by other triggers or the merge base cannot be determined.
 */
export const determineMergeBaseCommitOid = async function (
  checkoutPathOverride?: string,
): Promise<string | undefined> {
  if (getWorkflowEventName() !== "pull_request") {
    return undefined;
  }

  const mergeSha = getRequiredEnvParam("GITHUB_SHA");
  const checkoutPath =
    checkoutPathOverride ?? getOptionalInput("checkout_path");
  let stderr = "";

  try {
    let commitOid = "";
    let baseOid = "";
    let headOid = "";

    await new toolrunner.ToolRunner(
      await safeWhich.safeWhich("git"),
      ["show", "-s", "--format=raw", mergeSha],
      {
        silent: true,
        listeners: {
          stdline: (data) => {
            if (data.startsWith("commit ") && commitOid === "") {
              commitOid = data.substring(7);
            } else if (data.startsWith("parent ")) {
              if (baseOid === "") {
                baseOid = data.substring(7);
              } else if (headOid === "") {
                headOid = data.substring(7);
              }
            }
          },
          stderr: (data) => {
            stderr += data.toString();
          },
        },
        cwd: checkoutPath,
      },
    ).exec();

    // Let's confirm our assumptions: We had a merge commit and the parsed parent data looks correct
    if (
      commitOid === mergeSha &&
      headOid.length === 40 &&
      baseOid.length === 40
    ) {
      return baseOid;
    }
    return undefined;
  } catch (e) {
    if (stderr.includes("not a git repository")) {
      core.info(
        "The checkout path provided to the action does not appear to be a git repository. " +
          "Will calculate the merge base on the server.",
      );
    } else {
      core.info(
        `Failed to call git to determine merge base. Will calculate the merge base on ` +
          `the server. Reason: ${stderr}`,
      );
    }
    return undefined;
  }
};

/**
 * Get the ref currently being analyzed.
 */
export async function getRef(): Promise<string> {
  // Will be in the form "refs/heads/master" on a push event
  // or in the form "refs/pull/N/merge" on a pull_request event
  const refInput = getOptionalInput("ref");
  const shaInput = getOptionalInput("sha");
  const checkoutPath =
    getOptionalInput("checkout_path") ||
    getOptionalInput("source-root") ||
    getRequiredEnvParam("GITHUB_WORKSPACE");

  const hasRefInput = !!refInput;
  const hasShaInput = !!shaInput;
  // If one of 'ref' or 'sha' are provided, both are required
  if ((hasRefInput || hasShaInput) && !(hasRefInput && hasShaInput)) {
    throw new UserError(
      "Both 'ref' and 'sha' are required if one of them is provided.",
    );
  }

  const ref = refInput || getRefFromEnv();
  const sha = shaInput || getRequiredEnvParam("GITHUB_SHA");

  // If the ref is a user-provided input, we have to skip logic
  // and assume that it is really where they want to upload the results.
  if (refInput) {
    return refInput;
  }

  // For pull request refs we want to detect whether the workflow
  // has run `git checkout HEAD^2` to analyze the 'head' ref rather
  // than the 'merge' ref. If so, we want to convert the ref that
  // we report back.
  const pull_ref_regex = /refs\/pull\/(\d+)\/merge/;
  if (!pull_ref_regex.test(ref)) {
    return ref;
  }

  const head = await getCommitOid(checkoutPath, "HEAD");

  // in actions/checkout@v2+ we can check if git rev-parse HEAD == GITHUB_SHA
  // in actions/checkout@v1 this may not be true as it checks out the repository
  // using GITHUB_REF. There is a subtle race condition where
  // git rev-parse GITHUB_REF != GITHUB_SHA, so we must check
  // git rev-parse GITHUB_REF == git rev-parse HEAD instead.
  const hasChangedRef =
    sha !== head &&
    (await getCommitOid(
      checkoutPath,
      ref.replace(/^refs\/pull\//, "refs/remotes/pull/"),
    )) !== head;

  if (hasChangedRef) {
    const newRef = ref.replace(pull_ref_regex, "refs/pull/$1/head");
    core.debug(
      `No longer on merge commit, rewriting ref from ${ref} to ${newRef}.`,
    );
    return newRef;
  } else {
    return ref;
  }
}

function getRefFromEnv(): string {
  // To workaround a limitation of Actions dynamic workflows not setting
  // the GITHUB_REF in some cases, we accept also the ref within the
  // CODE_SCANNING_REF variable. When possible, however, we prefer to use
  // the GITHUB_REF as that is a protected variable and cannot be overwritten.
  let refEnv: string;
  try {
    refEnv = getRequiredEnvParam("GITHUB_REF");
  } catch (e) {
    // If the GITHUB_REF is not set, we try to rescue by getting the
    // CODE_SCANNING_REF.
    const maybeRef = process.env["CODE_SCANNING_REF"];
    if (maybeRef === undefined || maybeRef.length === 0) {
      throw e;
    }
    refEnv = maybeRef;
  }
  return refEnv;
}

export function getActionVersion(): string {
  return pkg.version!;
}

/**
 * Returns the name of the event that triggered this workflow.
 *
 * This will be "dynamic" for default setup workflow runs.
 */
export function getWorkflowEventName() {
  return getRequiredEnvParam("GITHUB_EVENT_NAME");
}

/**
 * Returns whether the current workflow is executing a local copy of the Action, e.g. we're running
 * a workflow on the codeql-action repo itself.
 */
export function isRunningLocalAction(): boolean {
  const relativeScriptPath = getRelativeScriptPath();
  return (
    relativeScriptPath.startsWith("..") || path.isAbsolute(relativeScriptPath)
  );
}

/**
 * Get the location where the Action is running from.
 *
 * This can be used to get the Action's name or tell if we're running a local Action.
 */
export function getRelativeScriptPath(): string {
  const runnerTemp = getRequiredEnvParam("RUNNER_TEMP");
  const actionsDirectory = path.join(path.dirname(runnerTemp), "_actions");
  return path.relative(actionsDirectory, __filename);
}

/** Returns the contents of `GITHUB_EVENT_PATH` as a JSON object. */
function getWorkflowEvent(): any {
  const eventJsonFile = getRequiredEnvParam("GITHUB_EVENT_PATH");
  try {
    return JSON.parse(fs.readFileSync(eventJsonFile, "utf-8"));
  } catch (e) {
    throw new Error(
      `Unable to read workflow event JSON from ${eventJsonFile}: ${e}`,
    );
  }
}

function removeRefsHeadsPrefix(ref: string): string {
  return ref.startsWith("refs/heads/") ? ref.slice("refs/heads/".length) : ref;
}

/**
 * Returns whether we are analyzing the default branch for the repository.
 *
 * This first checks the environment variable `CODE_SCANNING_IS_ANALYZING_DEFAULT_BRANCH`. This
 * environment variable can be set in cases where repository information might not be available, for
 * example dynamic workflows.
 */
export async function isAnalyzingDefaultBranch(): Promise<boolean> {
  if (process.env.CODE_SCANNING_IS_ANALYZING_DEFAULT_BRANCH === "true") {
    return true;
  }

  // Get the current ref and trim and refs/heads/ prefix
  let currentRef = await getRef();
  currentRef = removeRefsHeadsPrefix(currentRef);

  const event = getWorkflowEvent();
  let defaultBranch = event?.repository?.default_branch;

  if (getWorkflowEventName() === "schedule") {
    defaultBranch = removeRefsHeadsPrefix(getRefFromEnv());
  }

  return currentRef === defaultBranch;
}

export async function printDebugLogs(config: Config) {
  for (const language of config.languages) {
    const databaseDirectory = getCodeQLDatabasePath(config, language);
    const logsDirectory = path.join(databaseDirectory, "log");
    if (!doesDirectoryExist(logsDirectory)) {
      core.info(`Directory ${logsDirectory} does not exist.`);
      continue; // Skip this language database.
    }

    const walkLogFiles = (dir: string) => {
      const entries = fs.readdirSync(dir, { withFileTypes: true });
      if (entries.length === 0) {
        core.info(`No debug logs found at directory ${logsDirectory}.`);
      }
      for (const entry of entries) {
        if (entry.isFile()) {
          const absolutePath = path.resolve(dir, entry.name);
          core.startGroup(
            `CodeQL Debug Logs - ${language} - ${entry.name} from file at path ${absolutePath}`,
          );
          process.stdout.write(fs.readFileSync(absolutePath));
          core.endGroup();
        } else if (entry.isDirectory()) {
          walkLogFiles(path.resolve(dir, entry.name));
        }
      }
    };
    walkLogFiles(logsDirectory);
  }
}

export type UploadKind = "always" | "failure-only" | "never";

/**
 * Parses the `upload` input into an `UploadKind`, converting unspecified and deprecated upload
 * inputs appropriately.
 */
export function getUploadValue(input: string | undefined): UploadKind {
  switch (input) {
    case undefined:
    case "true":
    case "always":
      return "always";
    case "false":
    case "failure-only":
      return "failure-only";
    case "never":
      return "never";
    default:
      core.warning(
        `Unrecognized 'upload' input to 'analyze' Action: ${input}. Defaulting to 'always'.`,
      );
      return "always";
  }
}

/**
 * Get the workflow run ID.
 */
export function getWorkflowRunID(): number {
  const workflowRunIdString = getRequiredEnvParam("GITHUB_RUN_ID");
  const workflowRunID = parseInt(workflowRunIdString, 10);
  if (Number.isNaN(workflowRunID)) {
    throw new Error(
      `GITHUB_RUN_ID must define a non NaN workflow run ID. Current value is ${workflowRunIdString}`,
    );
  }
  if (workflowRunID < 0) {
    throw new Error(
      `GITHUB_RUN_ID must be a non-negative integer. Current value is ${workflowRunIdString}`,
    );
  }
  return workflowRunID;
}

/**
 * Get the workflow run attempt number.
 */
export function getWorkflowRunAttempt(): number {
  const workflowRunAttemptString = getRequiredEnvParam("GITHUB_RUN_ATTEMPT");
  const workflowRunAttempt = parseInt(workflowRunAttemptString, 10);
  if (Number.isNaN(workflowRunAttempt)) {
    throw new Error(
      `GITHUB_RUN_ATTEMPT must define a non NaN workflow run attempt. Current value is ${workflowRunAttemptString}`,
    );
  }
  if (workflowRunAttempt <= 0) {
    throw new Error(
      `GITHUB_RUN_ATTEMPT must be a positive integer. Current value is ${workflowRunAttemptString}`,
    );
  }
  return workflowRunAttempt;
}

/**
 * Tries to obtain the output of the `file` command for the file at the specified path.
 * The output will vary depending on the type of `file`, which operating system we are running on, etc.
 */
export const getFileType = async (filePath: string): Promise<string> => {
  let stderr = "";
  let stdout = "";
  try {
    // The `file` command will output information about the type of file pointed at by `filePath`.
    // For binary files, this may include e.g. whether they are static of dynamic binaries.
    // The `-L` switch instructs the command to follow symbolic links.
    await new toolrunner.ToolRunner(
      await safeWhich.safeWhich("file"),
      ["-L", filePath],
      {
        silent: true,
        listeners: {
          stdout: (data) => {
            stdout += data.toString();
          },
          stderr: (data) => {
            stderr += data.toString();
          },
        },
      },
    ).exec();
    return stdout.trim();
  } catch (e) {
    core.info(
      `Could not determine type of ${filePath} from ${stdout}. ${stderr}`,
    );

    throw e;
  }
};