import * as core from '@actions/core';
import * as exec from '@actions/exec';
import * as fs from "fs";
import * as os from 'os';
import * as path from 'path';

import * as api from './api-client';
import * as configUtils from './config-utils';
import * as sharedEnv from './shared-environment';

/**
 * Should the current action be aborted?
 *
 * This method should be called at the start of all CodeQL actions and they
 * should abort cleanly if this returns true without failing the action.
 * This method will call `core.setFailed` if necessary.
 */
export function should_abort(actionName: string, requireInitActionHasRun: boolean): boolean {

  // Check that required aspects of the environment are present
  const ref = process.env['GITHUB_REF'];
  if (ref === undefined) {
    core.setFailed('GITHUB_REF must be set.');
    return true;
  }

  // If the init action is required, then check the it completed successfully.
  if (requireInitActionHasRun && process.env[sharedEnv.CODEQL_ACTION_INIT_COMPLETED] === undefined) {
    core.setFailed('The CodeQL ' + actionName + ' action cannot be used unless the CodeQL init action is run first. Aborting.');
    return true;
  }

  return false;
}

/**
 * Get an environment parameter, but throw an error if it is not set.
 */
export function getRequiredEnvParam(paramName: string): string {
  const value = process.env[paramName];
  if (value === undefined || value.length === 0) {
    throw new Error(paramName + ' environment variable must be set');
  }
  core.debug(paramName + '=' + value);
  return value;
}

/**
 * Gets the SHA of the commit that is currently checked out.
 */
export async function getCommitOid(): 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.
  try {
    let commitOid = '';
    await exec.exec('git', ['rev-parse', 'HEAD'], {
      silent: true,
      listeners: {
        stdout: (data) => { commitOid += data.toString(); },
        stderr: (data) => { process.stderr.write(data); }
      }
    });
    return commitOid.trim();
  } catch (e) {
    core.info("Failed to call git to get current commit. Continuing with data from environment: " + e);
    return getRequiredEnvParam('GITHUB_SHA');
  }
}

/**
 * Get the path of the currently executing workflow.
 */
async function getWorkflowPath(): Promise<string> {
  const repo_nwo = getRequiredEnvParam('GITHUB_REPOSITORY').split("/");
  const owner = repo_nwo[0];
  const repo = repo_nwo[1];
  const run_id = Number(getRequiredEnvParam('GITHUB_RUN_ID'));

  const apiClient = api.getApiClient();
  const runsResponse = await apiClient.request('GET /repos/:owner/:repo/actions/runs/:run_id', {
    owner,
    repo,
    run_id
  });
  const workflowUrl = runsResponse.data.workflow_url;

  const workflowResponse = await apiClient.request('GET ' + workflowUrl);

  return workflowResponse.data.path;
}

/**
 * Get the analysis key paramter for the current job.
 *
 * This will combine the workflow path and current job name.
 * Computing this the first time requires making requests to
 * the github API, but after that the result will be cached.
 */
export async function getAnalysisKey(): Promise<string> {
  let analysisKey = process.env[sharedEnv.CODEQL_ACTION_ANALYSIS_KEY];
  if (analysisKey !== undefined) {
    return analysisKey;
  }

  const workflowPath = await getWorkflowPath();
  const jobName = getRequiredEnvParam('GITHUB_JOB');

  analysisKey = workflowPath + ':' + jobName;
  core.exportVariable(sharedEnv.CODEQL_ACTION_ANALYSIS_KEY, analysisKey);
  return analysisKey;
}

/**
 * Get the ref currently being analyzed.
 */
export function getRef(): 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 ref = getRequiredEnvParam('GITHUB_REF');

  // For pull request refs we want to convert from the 'merge' ref
  // to the 'head' ref, as that is what we want to analyse.
  // There should have been some code earlier in the workflow to do
  // the checkout, but we have no way of verifying that here.
  const pull_ref_regex = /refs\/pull\/(\d+)\/merge/;
  if (pull_ref_regex.test(ref)) {
    return ref.replace(pull_ref_regex, 'refs/pull/$1/head');
  } else {
    return ref;
  }
}

type ActionName = 'init' | 'autobuild' | 'finish' | 'upload-sarif';
type ActionStatus = 'starting' | 'aborted' | 'success' | 'failure';

interface StatusReport {
  "workflow_run_id": number;
  "workflow_name": string;
  "job_name": string;
  "analysis_key": string;
  "matrix_vars"?: string;
  "languages": string;
  "commit_oid": string;
  "ref": string;
  "action_name": ActionName;
  "action_oid": string;
  "started_at": string;
  "completed_at"?: string;
  "status": ActionStatus;
  "cause"?: string;
  "exception"?: string;
}

/**
 * Compose a StatusReport.
 *
 * @param actionName The name of the action, e.g. 'init', 'finish', 'upload-sarif'
 * @param status The status. Must be 'success', 'failure', or 'starting'
 * @param cause  Cause of failure (only supply if status is 'failure')
 * @param exception Exception (only supply if status is 'failure')
 */
async function createStatusReport(
  actionName: ActionName,
  status: ActionStatus,
  cause?: string,
  exception?: string):
  Promise<StatusReport> {

  // If this is not the init action starting up or aborting then try to load the config.
  // If it fails then carry because it's important to still send the status report.
  let config: configUtils.Config | undefined = undefined;
  if (actionName !== 'init' || (status !== 'starting' && status !== 'aborted')) {
    try {
      config = await configUtils.getConfig();
    } catch (e) {
      core.error('Unable to load config: ' + e);
    }
  }

  const commitOid = process.env['GITHUB_SHA'] || '';
  const ref = getRef();
  const workflowRunIDStr = process.env['GITHUB_RUN_ID'];
  let workflowRunID = -1;
  if (workflowRunIDStr) {
    workflowRunID = parseInt(workflowRunIDStr, 10);
  }
  const workflowName = process.env['GITHUB_WORKFLOW'] || '';
  const jobName = process.env['GITHUB_JOB'] || '';
  const analysis_key = await getAnalysisKey();
  const languages = config?.languages?.join(',') || "";
  const startedAt = process.env[sharedEnv.CODEQL_ACTION_STARTED_AT] || new Date().toISOString();
  core.exportVariable(sharedEnv.CODEQL_ACTION_STARTED_AT, startedAt);

  let statusReport: StatusReport = {
    workflow_run_id: workflowRunID,
    workflow_name: workflowName,
    job_name: jobName,
    analysis_key: analysis_key,
    languages: languages,
    commit_oid: commitOid,
    ref: ref,
    action_name: actionName,
    action_oid: "unknown", // TODO decide if it's possible to fill this in
    started_at: startedAt,
    status: status
  };

  // Add optional parameters
  if (cause) {
    statusReport.cause = cause;
  }
  if (exception) {
    statusReport.exception = exception;
  }
  if (status === 'success' || status === 'failure' || status === 'aborted') {
    statusReport.completed_at = new Date().toISOString();
  }
  let matrix: string | undefined = core.getInput('matrix');
  if (matrix) {
    statusReport.matrix_vars = matrix;
  }

  return statusReport;
}

/**
 * Send a status report to the code_scanning/analysis/status endpoint.
 *
 * Returns the status code of the response to the status request.
 */
async function sendStatusReport(statusReport: StatusReport): Promise<number> {
  const statusReportJSON = JSON.stringify(statusReport);

  core.debug('Sending status report: ' + statusReportJSON);

  const nwo = getRequiredEnvParam("GITHUB_REPOSITORY");
  const [owner, repo] = nwo.split("/");
  const statusResponse = await api.getApiClient().request('PUT /repos/:owner/:repo/code-scanning/analysis/status', {
    owner: owner,
    repo: repo,
    data: statusReportJSON,
  });
  return statusResponse.status;
}

/**
 * Send a status report that an action is starting.
 *
 * If the action is `init` then this also records the start time in the environment,
 * and ensures that the analysed languages are also recorded in the envirenment.
 *
 * Returns true unless a problem occurred and the action should abort.
 */
export async function reportActionStarting(action: ActionName): Promise<boolean> {
  const statusCode = await sendStatusReport(await createStatusReport(action, 'starting'));

  // If the status report request fails with a 403 or a 404, then this is a deliberate
  // message from the endpoint that the SARIF upload can be expected to fail too,
  // so the action should fail to avoid wasting actions minutes.
  //
  // Other failure responses (or lack thereof) could be transitory and should not
  // cause the action to fail.
  if (statusCode === 403) {
    core.setFailed('The repo on which this action is running is not opted-in to CodeQL code scanning.');
    return false;
  }
  if (statusCode === 404) {
    core.setFailed('Not authorized to used the CodeQL code scanning feature on this repo.');
    return false;
  }

  return true;
}

/**
 * Report that an action has failed.
 *
 * Note that the started_at date is always that of the `init` action, since
 * this is likely to give a more useful duration when inspecting events.
 */
export async function reportActionFailed(action: ActionName, cause?: string, exception?: string) {
  await sendStatusReport(await createStatusReport(action, 'failure', cause, exception));
}

/**
 * Report that an action has succeeded.
 *
 * Note that the started_at date is always that of the `init` action, since
 * this is likely to give a more useful duration when inspecting events.
 */
export async function reportActionSucceeded(action: ActionName) {
  await sendStatusReport(await createStatusReport(action, 'success'));
}

/**
 * Report that an action has been aborted.
 *
 * Note that the started_at date is always that of the `init` action, since
 * this is likely to give a more useful duration when inspecting events.
 */
export async function reportActionAborted(action: ActionName, cause?: string) {
  await sendStatusReport(await createStatusReport(action, 'aborted', cause));
}

/**
 * Get the array of all the tool names contained in the given sarif contents.
 *
 * Returns an array of unique string tool names.
 */
export function getToolNames(sarifContents: string): string[] {
  const sarif = JSON.parse(sarifContents);
  const toolNames = {};

  for (const run of sarif.runs || []) {
    const tool = run.tool || {};
    const driver = tool.driver || {};
    if (typeof driver.name === "string" && driver.name.length > 0) {
      toolNames[driver.name] = true;
    }
  }

  return Object.keys(toolNames);
}

// Creates a random temporary directory, runs the given body, and then deletes the directory.
// Mostly intended for use within tests.
export async function withTmpDir<T>(body: (tmpDir: string) => Promise<T>): Promise<T> {
  const tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), 'codeql-action-'));
  const realSubdir = path.join(tmpDir, 'real');
  fs.mkdirSync(realSubdir);
  const symlinkSubdir = path.join(tmpDir, 'symlink');
  fs.symlinkSync(realSubdir, symlinkSubdir, 'dir');
  const result = await body(symlinkSubdir);
  fs.rmdirSync(tmpDir, { recursive: true });
  return result;
}

/**
 * Get the codeql `--ram` flag as configured by the `ram` input. If no value was
 * specified, the total available memory will be used minus 256 MB.
 *
 * @returns string
 */
export function getMemoryFlag(): string {
  let memoryToUseMegaBytes: number;
  const memoryToUseString = core.getInput("ram");
  if (memoryToUseString) {
    memoryToUseMegaBytes = Number(memoryToUseString);
    if (Number.isNaN(memoryToUseMegaBytes) || memoryToUseMegaBytes <= 0) {
      throw new Error("Invalid RAM setting \"" + memoryToUseString + "\", specified.");
    }
  } else {
    const totalMemoryBytes = os.totalmem();
    const totalMemoryMegaBytes = totalMemoryBytes / (1024 * 1024);
    const systemReservedMemoryMegaBytes = 256;
    memoryToUseMegaBytes = totalMemoryMegaBytes - systemReservedMemoryMegaBytes;
  }
  return "--ram=" + Math.floor(memoryToUseMegaBytes);
}

/**
 * Get the codeql `--threads` value specified for the `threads` input. The value
 * defaults to 1. The value will be capped to the number of available CPUs.
 *
 * @returns string
 */
export function getThreadsFlag(): string {
  let numThreads = 1;
  const numThreadsString = core.getInput("threads");
  if (numThreadsString) {
    numThreads = Number(numThreadsString);
    if (Number.isNaN(numThreads)) {
      throw new Error(`Invalid threads setting "${numThreadsString}", specified.`);
    }
    const maxThreads = os.cpus().length;
    if (numThreads > maxThreads) {
      numThreads = maxThreads;
    }
    const minThreads = -maxThreads;
    if (numThreads < minThreads) {
      numThreads = minThreads;
    }
  }
  return `--threads=${numThreads}`;
}