import { mkdirSync, writeFileSync, promises as fsPromises } from "fs";
import { prompt } from "inquirer";
import path from "path";
import handlebars from "handlebars";
import semver from "semver";
import * as style from "../style";
import validateLicense = require("validate-npm-package-license");
import validateName = require("validate-npm-package-name");
import * as JSON from "ts-typed-json";
import gitconfig from "git-config";

const { readFile, stat } = fsPromises;

const ROOT_DIR = path.resolve(__dirname, "..", "..");
const TEMPLATES_DIR = path.resolve(ROOT_DIR, "templates");

const NEON_CLI_VERSION = JSON.asString(
  JSON.asObject(JSON.loadSync(path.resolve(ROOT_DIR, "package.json"))).version
);

async function compile(filename: string) {
  let source = await readFile(path.resolve(TEMPLATES_DIR, filename), {
    encoding: "utf8",
  });
  return handlebars.compile(source, { noEscape: true });
}

const GITIGNORE_TEMPLATE = compile(".gitignore.hbs");
const CARGO_TEMPLATE = compile("Cargo.toml.hbs");
const NPM_TEMPLATE = compile("package.json.hbs");
const INDEXJS_TEMPLATE = compile("index.js.hbs");
const LIBRS_TEMPLATE = compile("lib.rs.hbs");
const README_TEMPLATE = compile("README.md.hbs");
const BUILDRS_TEMPLATE = compile("build.rs.hbs");

type Author = {
  name?: string;
  email?: string;
};

async function guessAuthor() {
  let author: Author = {
    name: process.env.USER || process.env.USERNAME,
    email: undefined,
  };
  try {
    let config = gitconfig.sync();
    if (config.user.name) {
      author.name = config.user.name;
    }
    if (config.user.email) {
      author.email = config.user.email;
    }
    return author;
  } catch (e) {
    return author;
  }
}

type NeonVersion = {
  type: "version" | "range" | "relative" | "absolute";
  value: string;
};

async function parseNeonVersion(flag: string | null): Promise<NeonVersion> {
  if (!flag) {
    return { type: "version", value: NEON_CLI_VERSION };
  }

  if (semver.valid(flag)) {
    return { type: "version", value: flag };
  }

  if (semver.validRange(flag)) {
    return { type: "range", value: flag };
  }

  let stats = await stat(flag);

  if (!stats.isDirectory()) {
    throw new Error("Specified path to Neon is not a directory");
  }

  return { type: path.isAbsolute(flag) ? "absolute" : "relative", value: flag };
}

interface Answers {
  name: {
    npm: {
      full: string;
      scope: string | null;
      local: string;
    };
    cargo: {
      external: string;
      internal: string;
    };
  };
  description: string;
  git: string;
  author: string;
  node: string;
}

export default async function wizard(
  pwd: string,
  name: string,
  neon: string | null,
  features: string | null,
  noDefaultFeatures: boolean
) {
  let warning =
    "WARN: `neon new` is deprecated. To create a new project use `npm init neon my-project`.";
  let banner = "".padStart(warning.length + 4, "#");

  console.warn(`${banner}\n# ${warning} #\n${banner}\n`);

  let its = validateName(name);
  if (!its.validForNewPackages) {
    let errors = (its.errors || []).concat(its.warnings || []);
    throw new Error("Sorry, " + errors.join(" and ") + ".");
  }

  // check for a scoped name
  let scoped = name.match(/@([^\/]+)\/(.*)/);
  let [, scope, local] = scoped
    ? (scoped as [string, string, string])
    : [, null, name];

  console.log(
    "This utility will walk you through creating the " +
      style.project(name) +
      " Neon project."
  );
  console.log(
    "It only covers the most common items, and tries to guess sensible defaults."
  );
  console.log();
  console.log("Press ^C at any time to quit.");

  let root = path.resolve(pwd, local);
  let guess = await guessAuthor();

  let answers: Answers = await prompt([
    {
      type: "input",
      name: "version",
      message: "version",
      default: "0.1.0",
      validate: function (input) {
        if (semver.valid(input)) {
          return true;
        }
        return "Invalid version: " + input;
      },
    },
    { type: "input", name: "description", message: "description" },
    {
      type: "input",
      name: "node",
      message: "node entry point",
      default: "lib/index.js",
    },
    { type: "input", name: "git", message: "git repository" },
    { type: "input", name: "author", message: "author", default: guess.name },
    { type: "input", name: "email", message: "email", default: guess.email },
    {
      type: "input",
      name: "license",
      message: "license",
      default: "MIT",
      validate: function (input) {
        let its = validateLicense(input);
        if (its.validForNewPackages) {
          return true;
        }
        let errors = its.warnings || [];
        return "Sorry, " + errors.join(" and ") + ".";
      },
    },
  ]);

  answers.name = {
    npm: {
      full: name,
      scope: scope,
      local: local,
    },
    cargo: {
      external: local,
      internal: local.replace(/-/g, "_"),
    },
  };
  answers.description = escapeQuotes(answers.description);
  answers.git = encodeURI(answers.git);
  answers.author = escapeQuotes(answers.author);

  let neonVersion = await parseNeonVersion(neon);

  let simple =
    (neonVersion.type === "version" || neonVersion.type === "range") &&
    !features &&
    !noDefaultFeatures;

  let libs: {
    // In the common case, we can make the Cargo.toml manifest simple by just using
    // the semver specifier string for the `neon` and `neon-build` dependencies.
    simple: boolean;
    paths?: { neon: string; "neon-build": string };
    version?: string;
    features?: Array<string>;
    noDefaultFeatures: boolean;
  } = { simple, noDefaultFeatures };

  if (neonVersion.type === "relative") {
    let neon = path.relative(path.join(name, "native"), neonVersion.value);
    libs.paths = {
      neon: JSON.stringify(neon),
      "neon-build": JSON.stringify(path.join(neon, "crates", "neon-build")),
    };
  } else if (neonVersion.type === "absolute") {
    libs.paths = {
      neon: JSON.stringify(neonVersion.value),
      "neon-build": JSON.stringify(
        path.resolve(neonVersion.value, "crates", "neon-build")
      ),
    };
  } else {
    libs.version = JSON.stringify(neonVersion.value);
  }

  if (features) {
    libs.features = features.split(/\s+/).map(JSON.stringify);
  }

  let cli = JSON.stringify(
    neonVersion.type === "version"
      ? "^" + neonVersion.value
      : neonVersion.type === "relative"
      ? "file:" + path.join(path.relative(name, neonVersion.value), "cli")
      : neonVersion.type === "absolute"
      ? "file:" + path.resolve(neonVersion.value, "cli")
      : neonVersion.value
  );

  let ctx = {
    project: answers,
    neon: { cli, libs },
  };

  let lib = path.resolve(root, path.dirname(answers.node));
  let native_ = path.resolve(root, "native");
  let src = path.resolve(native_, "src");

  mkdirSync(lib, { recursive: true });
  mkdirSync(src, { recursive: true });

  writeFileSync(
    path.resolve(root, ".gitignore"),
    (await GITIGNORE_TEMPLATE)(ctx),
    { flag: "wx" }
  );
  writeFileSync(path.resolve(root, "package.json"), (await NPM_TEMPLATE)(ctx), {
    flag: "wx",
  });
  writeFileSync(
    path.resolve(native_, "Cargo.toml"),
    (await CARGO_TEMPLATE)(ctx),
    { flag: "wx" }
  );
  writeFileSync(path.resolve(root, "README.md"), (await README_TEMPLATE)(ctx), {
    flag: "wx",
  });
  writeFileSync(
    path.resolve(root, answers.node),
    (await INDEXJS_TEMPLATE)(ctx),
    { flag: "wx" }
  );
  writeFileSync(path.resolve(src, "lib.rs"), (await LIBRS_TEMPLATE)(ctx), {
    flag: "wx",
  });
  writeFileSync(
    path.resolve(native_, "build.rs"),
    (await BUILDRS_TEMPLATE)(ctx),
    { flag: "wx" }
  );

  let relativeRoot = path.relative(pwd, root);
  let relativeNode = path.relative(pwd, path.resolve(root, answers.node));
  let relativeRust = path.relative(pwd, path.resolve(src, "lib.rs"));

  console.log();
  console.log(
    "Woo-hoo! Your Neon project has been created in: " +
      style.path(relativeRoot)
  );
  console.log();
  console.log("The main Node entry point is at: " + style.path(relativeNode));
  console.log("The main Rust entry point is at: " + style.path(relativeRust));
  console.log();
  console.log(
    "To build your project, just run " +
      style.command("npm install") +
      " from within the " +
      style.path(relativeRoot) +
      " directory."
  );
  console.log(
    "Then you can test it out with " +
      style.command("node -e 'require(\"./\")'") +
      "."
  );
  console.log();
  console.log("Happy hacking!");
}

function escapeQuotes(str: string): string {
  return str.replace(/"/g, '\\"');
}