var promisify = require("promisify-node");
var path = require("path");
var fs = require("fs");

var prepareForBuild = require("./prepareForBuild");

var exec = promisify(function(command, opts, callback) {
  return require("child_process").exec(command, opts, callback);
});

var fromRegistry;
try {
  fs.statSync(path.join(__dirname, "..", "include"));
  fs.statSync(path.join(__dirname, "..", "src"));
  fromRegistry = true;
}
catch(e) {
  fromRegistry = false;
}

if (!fromRegistry) {
  console.info("[nodegit] Local install, no fetching allowed.");
  return prepareAndBuild();
}
if (process.env.BUILD_DEBUG) {
  console.info("[nodegit] Doing a debug build, no fetching allowed.");
  return prepareAndBuild();
}
if (process.env.BUILD_ONLY) {
  console.info("[nodegit] BUILD_ONLY is set to true, no fetching allowed.");
  return prepareAndBuild();
}

return installPrebuilt();

function installPrebuilt() {
  console.info("[nodegit] Fetching binary from S3.");
  var npg = pathForTool("node-pre-gyp");
  return exec(npg + " install --fallback-to-build=false")
    .then(
      function() {
        console.info("[nodegit] Completed installation successfully.");
      },
      function(err) {
        console.info("[nodegit] Failed to install prebuilt binary:");
        console.error(err);
        console.info("[nodegit] Building manually. (You'll be here a while.)");
        return prepareAndBuild();
      }
    );
}

function pathForTool(name) {
  var toolPath = path.resolve(".", "node_modules", ".bin", name);
  toolPath = "\"" + toolPath + "\"";
  return toolPath;
}

function prepareAndBuild() {
  console.info("[nodegit] Regenerating and configuring code");
  return prepareForBuild()
    .then(function() {
      return build();
    });
}

function build() {
  console.info("[nodegit] Everything is ready to go, attempting compilation");

  var electronVersion = process.env.ELECTRON_VERSION;
  var nwjsVersion = process.env.NWJS_VERSION;
  var opts = {
    cwd: ".",
    maxBuffer: Number.MAX_VALUE,
    env: process.env
  };

  var builder = "node-gyp";
  var debug = (process.env.BUILD_DEBUG ? " --debug" : "");
  var target = "";
  var distUrl;

  process.argv.forEach(function(arg) {
    if (~arg.indexOf("electronVersion")) {
      electronVersion = arg.split("=")[1].trim();
    }
    else if (~arg.indexOf("nsjwVersion")) {
      nwjsVersion = arg.split("=")[1].trim();
    }
  });

  if (electronVersion) {
    target = "--target=" + electronVersion;
    distUrl = "--dist-url=https://gh-contractor-zcbenz.s3." +
      "amazonaws.com/atom-shell/dist";
  }
  else if (nwjsVersion) {
    builder = "nw-gyp";
    target = "--target=" + nwjsVersion;
  }

  var home = process.platform == "win32" ?
              process.env.USERPROFILE : process.env.HOME;

  opts.env.HOME = path.join(home, ".nodegit-gyp");

  var cmd = [
    pathForTool(builder),
    "rebuild",
    debug,
    target,
    distUrl
  ]
  .join(" ")
  .trim();

  return exec(cmd, opts)
    .then(function() {
        console.info("[nodegit] Compilation complete.");
        console.info("[nodegit] Completed installation successfully.");
        process.exitCode = 0;
      },
      function(err, stderr) {
        console.error(err);
        console.error(stderr);
        process.exitCode = 13;
      }
    );
}