import gulp from "gulp";
import cp from "child_process";
import hugoBin from "hugo-bin";
import gutil from "gulp-util";
import postcss from "gulp-postcss";
import transform from "gulp-transform";
import yaml from "yamljs";
import rename from "gulp-rename";
import cssImport from "postcss-import";
import neatgrid from "postcss-neat";
import nestedcss from "postcss-nested";
import colorfunctions from "postcss-colour-functions";
import hdBackgrounds from "postcss-at2x";
import cssvars from "postcss-simple-vars-async";
import cssextend from "postcss-simple-extend";
import styleVariables from "./config/variables";
import BrowserSync from "browser-sync";
import webpack from "webpack";
import webpackConfig from "./webpack.conf";
import url from "url";

// Always exit non-zero on unhandled promise rejection
process.on('unhandledRejection', err => { throw err });

const browserSync = BrowserSync.create();
const defaultArgs = ["-d", "../dist", "-s", "site", "-v"];

function buildSite(cb, options) {
  const args = options ? defaultArgs.concat(options) : defaultArgs;
  return cp.spawn(hugoBin, args, { stdio: "inherit" }).on("close", code => {
    if (code === 0) {
      browserSync.reload();
      cb();
    } else {
      browserSync.notify("Hugo build failed :(");
      cb("Hugo build failed");
    }
  });
}

gulp.task("hugo", ["copy"], cb => buildSite(cb));
gulp.task("hugo-preview", ["copy"], cb =>
  buildSite(cb, ["--buildDrafts", "--buildFuture"])
);

gulp.task("build", ["css", "js", "images", "hugo"]);
gulp.task("build-preview", ["css", "js", "images", "hugo-preview"]);

gulp.task("css", () =>
  gulp
    .src("./src/css/**/*.css")
    .pipe(
      postcss([
        cssImport({ from: "./src/css/main.css" }),
        neatgrid(),
        nestedcss(),
        colorfunctions(),
        hdBackgrounds(),
        cssextend(),
        cssvars({ variables: styleVariables })
      ])
    )
    .pipe(gulp.dest("./dist/css"))
    .pipe(browserSync.stream())
);

gulp.task("js", cb => {
  const myConfig = Object.assign({}, webpackConfig);

  webpack(myConfig, (err, stats) => {
    if (err) throw new gutil.PluginError("webpack", err);
    gutil.log(
      "[webpack]",
      stats.toString({
        colors: true,
        progress: true
      })
    );
    browserSync.reload();
    cb();
  });
});

gulp.task("images", () =>
  gulp
    .src("./src/img/**/*")
    .pipe(gulp.dest("./dist/img"))
    .pipe(browserSync.stream())
);

gulp.task("copy", () =>
  gulp
    .src("../.all-contributorsrc")
    .pipe(
      transform(
        "utf8",
        content =>
          new Promise((resolve, reject) => {
            const contributors = JSON.parse(content).contributors.map(c => {
              const avatar = url.parse(c['avatar_url'], true);
              avatar.search = undefined; // Override so that we can use `avatar.query`.
              if (avatar.hostname.endsWith('githubusercontent.com')) {
                // Use 32px avatars, instead of full-size.
                avatar.query['s'] = '32';
              }
              const avatar_url = url.format(avatar);
              return Object.assign({}, c, { avatar_url });
            });
            resolve(yaml.dump({ contributors }));
          })
      )
    )
    .pipe(rename("contributors.yml"))
    .pipe(gulp.dest("./site/data"))
);

gulp.task("server", ["css", "js", "images", "hugo"], () => {
  browserSync.init({
    server: {
      baseDir: "./dist"
    },
    notify: false
  });
  gulp.watch("./src/js/**/*.js", ["js"]);
  gulp.watch("./src/css/**/*.css", ["css"]);
  gulp.watch("./src/img/**/*", ["images"]);
  gulp.watch("./site/**/*", ["hugo"]);
});