import path from 'path';
import inquirer from 'inquirer';
import boxen from 'boxen';
import chalk from 'chalk';
import fs from 'fs';
import { filesystemSync } from 'fs-filesystem';

function showMsg(msg) {
  console.log(boxen(chalk.white(msg), {
    padding: 1,
    margin: 1,
    borderStyle: 'round',
    borderColor: 'white',
    titleAlignment: 'center'
  }));
}

function getAvailableRoots() {
  const devices = filesystemSync();
  var mountPoints = [];
  Object.keys(devices).forEach(function(key) {
      var val = devices[key];
      val.volumes.forEach(function(volume) {
          mountPoints.push(volume.mountPoint);
      });
    });

  if (mountPoints.length < 1) {
    throw new Error("Failed to detect file system devices.");
  }
  return mountPoints;
}

function splitPath(str) {
  return str.replaceAll("\\", "/").split("/");
}

function dropEmptyParts(parts) {
  var result = [];
  parts.forEach(function(part) {
    if (part.length > 0) {
      result.push(part);
    }
  })
  return result;
}

function combine(parts) {
  const toJoin = dropEmptyParts(parts);
  if (toJoin.length == 1) return toJoin[0];
  return path.join(...toJoin);
}

function combineWith(parts, extra) {
  const toJoin = dropEmptyParts(parts);
  if (toJoin.length == 1) return path.join(toJoin[0], extra);
  return path.join(...toJoin, extra);
}

function showCurrent(currentPath) {
  const len = currentPath.length;
  showMsg(`Current path: [${len}]\n` + combine(currentPath));

  if (len < 2) {
    showMsg(
      'Warning - Known issue:\n' +
      'Path selection does not work in root paths on some platforms.\n' +
      'Use "Enter path" or "Create new folder" to navigate and create folders\n' +
      'if this is the case for you.'
    );
  }
}

function hasValidRoot(roots, checkPath) {
  if (checkPath.length < 1) return false;
  var result = false;
  roots.forEach(function(root) {
    if (root.toLowerCase() == checkPath[0].toLowerCase()) {
      console.log("valid root: " + combine(checkPath));
      result = true;
    }
  });
  if (!result) console.log("invalid root: " + combine(checkPath));
  return result;
}

async function showMain(currentPath) {
  showCurrent(currentPath);
  const { choice } = await inquirer.prompt([
    {
        type: 'list',
        name: 'choice',
        message: 'Select an option:',
        choices: [
            '1. Enter path',
            '2. Go up one',
            '3. Go down one',
            '4. Create new folder here',
            '5. Select this path',
            '6. Cancel'
        ],
        pageSize: 6,
        loop: true
    }
  ]).catch(() => {
    handleExit();
    return { choice: '6' };
  });

  return choice;
}

export async function showPathSelector(startingPath, pathMustExist) {
  const roots = getAvailableRoots();
  var currentPath = splitPath(startingPath);
  if (!hasValidRoot(roots, currentPath)) {
    currentPath = [roots[0]];
  }

  while (true) {
    const choice = await showMain(currentPath);

    var newCurrentPath = currentPath;
    switch (choice.split('.')[0]) {
      case '1':
          newCurrentPath = await enterPath(currentPath, pathMustExist);
          break;
      case '2':
          newCurrentPath = upOne(currentPath);
          break;
      case '3':
          newCurrentPath = await downOne(currentPath);
          break;
      case '4':
          newCurrentPath = await createSubDir(currentPath, pathMustExist);
          break;
      case '5':
        if (pathMustExist && !isDir(combine(currentPath))) {
          console.log("Current path does not exist.");
          break;
        } else {
          return combine(currentPath);
        }
      case '6':
          return combine(currentPath);
    }

    if (hasValidRoot(roots, newCurrentPath)) {
      currentPath = newCurrentPath;
    } else {
      console.log("Selected path has no valid root.");
    }
  }
}

async function enterPath(currentPath, pathMustExist) {
  const response = await inquirer.prompt([
    {
        type: 'input',
        name: 'path',
        message: 'Enter Path:'
    }]);

  const newPath = response.path;
  if (pathMustExist && !isDir(newPath)) {
    console.log("The entered path does not exist.");
    return currentPath;
  }
  return splitPath(response.path);
}

function upOne(currentPath) {
  return currentPath.slice(0, currentPath.length - 1);
}

export function isDir(dir) {
  try {
    return fs.lstatSync(dir).isDirectory();
  } catch {
    return false;
  }
}

function isSubDir(currentPath, entry) {
  const newPath = combineWith(currentPath, entry);
  return isDir(newPath);
}

function getSubDirOptions(currentPath) {
  const fullPath = combine(currentPath);
  const entries = fs.readdirSync(fullPath);
  var result = [];
  var counter = 1;
  entries.forEach(function(entry) {
    if (isSubDir(currentPath, entry)) {
      result.push(counter + '. ' + entry);
      counter = counter + 1;
    }
  });
  return result;
}

async function downOne(currentPath) {
  const options = getSubDirOptions(currentPath);
  if (options.length == 0) {
    console.log("There are no subdirectories here.");
    return currentPath;
  }

  const { choice } = await inquirer.prompt([
    {
        type: 'list',
        name: 'choice',
        message: 'Select an subdir:',
        choices: options,
        pageSize: options.length,
        loop: true
    }
  ]).catch(() => {
    return currentPath;
  });

  const subDir = choice.split('. ')[1];
  return [...currentPath, subDir];
}

async function createSubDir(currentPath, pathMustExist) {
  const response = await inquirer.prompt([
    {
        type: 'input',
        name: 'name',
        message: 'Enter name:'
    }]);

  const name = response.name;
  if (name.length < 1) return;

  const fullDir = combineWith(currentPath, name);
  if (pathMustExist && !isDir(fullDir)) {
    fs.mkdirSync(fullDir);
  }
  return [...currentPath, name];
}