#!/bin/sh
#
# This script should be run via curl:
#   sh -c "$(curl -fsSL https://raw.githubusercontent.com/ohmyzsh/ohmyzsh/master/tools/install.sh)"
# or via wget:
#   sh -c "$(wget -qO- https://raw.githubusercontent.com/ohmyzsh/ohmyzsh/master/tools/install.sh)"
# or via fetch:
#   sh -c "$(fetch -o - https://raw.githubusercontent.com/ohmyzsh/ohmyzsh/master/tools/install.sh)"
#
# As an alternative, you can first download the install script and run it afterwards:
#   wget https://raw.githubusercontent.com/ohmyzsh/ohmyzsh/master/tools/install.sh
#   sh install.sh
#
# You can tweak the install behavior by setting variables when running the script. For
# example, to change the path to the Oh My Zsh repository:
#   ZSH=~/.zsh sh install.sh
#
# Respects the following environment variables:
#   ZSH     - path to the Oh My Zsh repository folder (default: $HOME/.oh-my-zsh)
#   REPO    - name of the GitHub repo to install from (default: ohmyzsh/ohmyzsh)
#   REMOTE  - full remote URL of the git repo to install (default: GitHub via HTTPS)
#   BRANCH  - branch to check out immediately after install (default: master)
#
# Other options:
#   CHSH       - 'no' means the installer will not change the default shell (default: yes)
#   RUNZSH     - 'no' means the installer will not run zsh after the install (default: yes)
#   KEEP_ZSHRC - 'yes' means the installer will not replace an existing .zshrc (default: no)
#
# You can also pass some arguments to the install script to set some these options:
#   --skip-chsh: has the same behavior as setting CHSH to 'no'
#   --unattended: sets both CHSH and RUNZSH to 'no'
#   --keep-zshrc: sets KEEP_ZSHRC to 'yes'
# For example:
#   sh install.sh --unattended
# or:
#   sh -c "$(curl -fsSL https://raw.githubusercontent.com/ohmyzsh/ohmyzsh/master/tools/install.sh)" "" --unattended
#
set -e

# Track if $ZSH was provided
custom_zsh=${ZSH:+yes}

# Default settings
ZSH=${ZSH:-~/.oh-my-zsh}
REPO=${REPO:-ohmyzsh/ohmyzsh}
REMOTE=${REMOTE:-https://github.com/${REPO}.git}
BRANCH=${BRANCH:-master}

# Other options
CHSH=${CHSH:-yes}
RUNZSH=${RUNZSH:-yes}
KEEP_ZSHRC=${KEEP_ZSHRC:-no}


command_exists() {
  command -v "$@" >/dev/null 2>&1
}

fmt_error() {
  printf '%sError: %s%s\n' "$BOLD$RED" "$*" "$RESET" >&2
}

fmt_underline() {
  printf '\033[4m%s\033[24m\n' "$*"
}

fmt_code() {
  # shellcheck disable=SC2016 # backtick in single-quote
  printf '`\033[38;5;247m%s%s`\n' "$*" "$RESET"
}

setup_color() {
  # Only use colors if connected to a terminal
  if [ -t 1 ]; then
    RED=$(printf '\033[31m')
    GREEN=$(printf '\033[32m')
    YELLOW=$(printf '\033[33m')
    BLUE=$(printf '\033[34m')
    BOLD=$(printf '\033[1m')
    RESET=$(printf '\033[m')
  else
    RED=""
    GREEN=""
    YELLOW=""
    BLUE=""
    BOLD=""
    RESET=""
  fi
}

setup_ohmyzsh() {
  # Prevent the cloned repository from having insecure permissions. Failing to do
  # so causes compinit() calls to fail with "command not found: compdef" errors
  # for users with insecure umasks (e.g., "002", allowing group writability). Note
  # that this will be ignored under Cygwin by default, as Windows ACLs take
  # precedence over umasks except for filesystems mounted with option "noacl".
  umask g-w,o-w

  echo "${BLUE}Cloning Oh My Zsh...${RESET}"

  command_exists git || {
    fmt_error "git is not installed"
    exit 1
  }

  ostype=$(uname)
  if [ -z "${ostype%CYGWIN*}" ] && git --version | grep -q msysgit; then
    fmt_error "Windows/MSYS Git is not supported on Cygwin"
    fmt_error "Make sure the Cygwin git package is installed and is first on the \$PATH"
    exit 1
  fi

  git clone -c core.eol=lf -c core.autocrlf=false \
    -c fsck.zeroPaddedFilemode=ignore \
    -c fetch.fsck.zeroPaddedFilemode=ignore \
    -c receive.fsck.zeroPaddedFilemode=ignore \
    -c oh-my-zsh.remote=origin \
    -c oh-my-zsh.branch="$BRANCH" \
    --depth=1 --branch "$BRANCH" "$REMOTE" "$ZSH" || {
    fmt_error "git clone of oh-my-zsh repo failed"
    exit 1
  }

  echo
}

setup_zshrc() {
  # Keep most recent old .zshrc at .zshrc.pre-oh-my-zsh, and older ones
  # with datestamp of installation that moved them aside, so we never actually
  # destroy a user's original zshrc
  echo "${BLUE}Looking for an existing zsh config...${RESET}"

  # Must use this exact name so uninstall.sh can find it
  OLD_ZSHRC=~/.zshrc.pre-oh-my-zsh
  if [ -f ~/.zshrc ] || [ -h ~/.zshrc ]; then
    # Skip this if the user doesn't want to replace an existing .zshrc
    if [ "$KEEP_ZSHRC" = yes ]; then
      echo "${YELLOW}Found ~/.zshrc.${RESET} ${GREEN}Keeping...${RESET}"
      return
    fi
    if [ -e "$OLD_ZSHRC" ]; then
      OLD_OLD_ZSHRC="${OLD_ZSHRC}-$(date +%Y-%m-%d_%H-%M-%S)"
      if [ -e "$OLD_OLD_ZSHRC" ]; then
        fmt_error "$OLD_OLD_ZSHRC exists. Can't back up ${OLD_ZSHRC}"
        fmt_error "re-run the installer again in a couple of seconds"
        exit 1
      fi
      mv "$OLD_ZSHRC" "${OLD_OLD_ZSHRC}"

      echo "${YELLOW}Found old ~/.zshrc.pre-oh-my-zsh." \
        "${GREEN}Backing up to ${OLD_OLD_ZSHRC}${RESET}"
    fi
    echo "${YELLOW}Found ~/.zshrc.${RESET} ${GREEN}Backing up to ${OLD_ZSHRC}${RESET}"
    mv ~/.zshrc "$OLD_ZSHRC"
  fi

  echo "${GREEN}Using the Oh My Zsh template file and adding it to ~/.zshrc.${RESET}"

  sed "/^export ZSH=/ c\\
export ZSH=\"$ZSH\"
" "$ZSH/templates/zshrc.zsh-template" > ~/.zshrc-omztemp
  mv -f ~/.zshrc-omztemp ~/.zshrc

  echo
}

setup_shell() {
  # Skip setup if the user wants or stdin is closed (not running interactively).
  if [ "$CHSH" = no ]; then
    return
  fi

  # If this user's login shell is already "zsh", do not attempt to switch.
  if [ "$(basename -- "$SHELL")" = "zsh" ]; then
    return
  fi

  # If this platform doesn't provide a "chsh" command, bail out.
  if ! command_exists chsh; then
    cat <<EOF
I can't change your shell automatically because this system does not have chsh.
${BLUE}Please manually change your default shell to zsh${RESET}
EOF
    return
  fi

  echo "${BLUE}Time to change your default shell to zsh:${RESET}"

  # Prompt for user choice on changing the default login shell
  printf '%sDo you want to change your default shell to zsh? [Y/n]%s ' \
    "$YELLOW" "$RESET"
  read -r opt
  case $opt in
    y*|Y*|"") echo "Changing the shell..." ;;
    n*|N*) echo "Shell change skipped."; return ;;
    *) echo "Invalid choice. Shell change skipped."; return ;;
  esac

  # Check if we're running on Termux
  case "$PREFIX" in
    *com.termux*) termux=true; zsh=zsh ;;
    *) termux=false ;;
  esac

  if [ "$termux" != true ]; then
    # Test for the right location of the "shells" file
    if [ -f /etc/shells ]; then
      shells_file=/etc/shells
    elif [ -f /usr/share/defaults/etc/shells ]; then # Solus OS
      shells_file=/usr/share/defaults/etc/shells
    else
      fmt_error "could not find /etc/shells file. Change your default shell manually."
      return
    fi

    # Get the path to the right zsh binary
    # 1. Use the most preceding one based on $PATH, then check that it's in the shells file
    # 2. If that fails, get a zsh path from the shells file, then check it actually exists
    if ! zsh=$(command -v zsh) || ! grep -qx "$zsh" "$shells_file"; then
      if ! zsh=$(grep '^/.*/zsh$' "$shells_file" | tail -1) || [ ! -f "$zsh" ]; then
        fmt_error "no zsh binary found or not present in '$shells_file'"
        fmt_error "change your default shell manually."
        return
      fi
    fi
  fi

  # We're going to change the default shell, so back up the current one
  if [ -n "$SHELL" ]; then
    echo "$SHELL" > ~/.shell.pre-oh-my-zsh
  else
    grep "^$USERNAME:" /etc/passwd | awk -F: '{print $7}' > ~/.shell.pre-oh-my-zsh
  fi

  # Actually change the default shell to zsh
  if ! chsh -s "$zsh"; then
    fmt_error "chsh command unsuccessful. Change your default shell manually."
  else
    export SHELL="$zsh"
    echo "${GREEN}Shell successfully changed to '$zsh'.${RESET}"
  fi

  echo
}

main() {
  # Run as unattended if stdin is not a tty
  if [ ! -t 0 ]; then
    RUNZSH=no
    CHSH=no
  fi

  # Parse arguments
  while [ $# -gt 0 ]; do
    case $1 in
      --unattended) RUNZSH=no; CHSH=no ;;
      --skip-chsh) CHSH=no ;;
      --keep-zshrc) KEEP_ZSHRC=yes ;;
    esac
    shift
  done

  setup_color

  if ! command_exists zsh; then
    echo "${YELLOW}Zsh is not installed.${RESET} Please install zsh first."
    exit 1
  fi

  if [ -d "$ZSH" ]; then
    echo "${YELLOW}The \$ZSH folder already exists ($ZSH).${RESET}"
    if [ "$custom_zsh" = yes ]; then
      cat <<EOF

You ran the installer with the \$ZSH setting or the \$ZSH variable is
exported. You have 3 options:

1. Unset the ZSH variable when calling the installer:
   $(fmt_code "ZSH= sh install.sh")
2. Install Oh My Zsh to a directory that doesn't exist yet:
   $(fmt_code "ZSH=path/to/new/ohmyzsh/folder sh install.sh")
3. (Caution) If the folder doesn't contain important information,
   you can just remove it with $(fmt_code "rm -r $ZSH")

EOF
    else
      echo "You'll need to remove it if you want to reinstall."
    fi
    exit 1
  fi

  setup_ohmyzsh
  setup_zshrc
  setup_shell

  printf %s "$GREEN"
  cat <<'EOF'
         __                                     __
  ____  / /_     ____ ___  __  __   ____  _____/ /_
 / __ \/ __ \   / __ `__ \/ / / /  /_  / / ___/ __ \
/ /_/ / / / /  / / / / / / /_/ /    / /_(__  ) / / /
\____/_/ /_/  /_/ /_/ /_/\__, /    /___/____/_/ /_/
                        /____/                       ....is now installed!


EOF
  cat <<EOF
Before you scream Oh My Zsh! please look over the ~/.zshrc file to select plugins, themes, and options.

• Follow us on Twitter: $(fmt_underline https://twitter.com/ohmyzsh)
• Join our Discord server: $(fmt_underline https://discord.gg/ohmyzsh)
• Get stickers, shirts, coffee mugs and other swag: $(fmt_underline https://shop.planetargon.com/collections/oh-my-zsh)

EOF
  printf %s "$RESET"

  if [ $RUNZSH = no ]; then
    echo "${YELLOW}Run zsh to try it out.${RESET}"
    exit
  fi

  exec zsh -l
}

main "$@"