#!/bin/bash

# Options
#
#   -V, --verbose
#     Enable verbose output for the installer
#
#   -f, -y, --force, --yes
#     Skip the confirmation prompt during installation
#
#   -p, --platform
#     Override the platform identified by the installer
#
#   -b, --bin-dir
#     Override the bin installation directory
#
#   -a, --arch
#     Override the architecture identified by the installer
#
#   -B, --base-url
#     Override the base URL used for downloading releases

set -euo pipefail
printf "\n"

BOLD="$(tput bold 2>/dev/null || echo '')"
GREY="$(tput setaf 0 2>/dev/null || echo '')"
UNDERLINE="$(tput smul 2>/dev/null || echo '')"
RED="$(tput setaf 1 2>/dev/null || echo '')"
GREEN="$(tput setaf 2 2>/dev/null || echo '')"
YELLOW="$(tput setaf 3 2>/dev/null || echo '')"
BLUE="$(tput setaf 4 2>/dev/null || echo '')"
MAGENTA="$(tput setaf 5 2>/dev/null || echo '')"
NO_COLOR="$(tput sgr0 2>/dev/null || echo '')"

info() {
  printf "%s\n" "${BOLD}${GREY}>${NO_COLOR} $*"
}

warn() {
  printf "%s\n" "${YELLOW}! $*${NO_COLOR}"
}

error() {
  printf "%s\n" "${RED}x $*${NO_COLOR}" >&2
}

complete() {
  printf "%s\n" "${GREEN}✓${NO_COLOR} $*"
}

# Gets path to a temporary file, even if
get_tmpfile() {
  local suffix
  suffix="$1"
  if hash mktemp; then
    printf "%s.%s" "$(mktemp)" "${suffix}"
  else
    # No really good options here--let's pick a default + hope
    printf "/tmp/starship.%s" "${suffix}"
  fi
}

# Test if a location is writeable by trying to write to it. Windows does not let
# you test writeability other than by writing: https://stackoverflow.com/q/1999988
test_writeable() {
  local path
  path="${1:-}/test.txt"
  if touch "${path}" 2>/dev/null; then
    rm "${path}"
    return 0
  else
    return 1
  fi
}

fetch() {
  local command
  if hash curl 2>/dev/null; then
    set +e
    command="curl --silent --fail --location $1"
    curl --silent --fail --location "$1"
    rc=$?
    set -e
  else
    if hash wget 2>/dev/null; then
      set +e
      command="wget -O- -q $1"
      wget -O- -q "$1"
      rc=$?
      set -e
    else
      error "No HTTP download program (curl, wget) found…"
      exit 1
    fi
  fi

  if [ $rc -ne 0 ]; then
    printf "\n" >&2
    error "Command failed (exit code $rc): ${BLUE}${command}${NO_COLOR}"
    printf "\n" >&2
    info "This is likely due to Starship not yet supporting your configuration." >&2
    info "If you would like to see a build for your configuration," >&2
    info "please create an issue requesting a build for ${MAGENTA}${ARCH}-${PLATFORM}${NO_COLOR}:" >&2
    info "${BOLD}${UNDERLINE}https://github.com/starship/starship/issues/new/${NO_COLOR}\n" >&2
    exit $rc
  fi
}

fetch_and_unpack() {
  local sudo
  local tmpfile
  sudo="$1"
  # I'd like to separate this into a fetch() and unpack() function, but I can't
  # figure out how to get bash functions to read STDIN/STDOUT from pipes
  if [ "${EXT}" = "tar.gz" ]; then
    fetch "${URL}" | ${sudo} tar xz"${VERBOSE}"f - -C "${BIN_DIR}"
  elif [ "${EXT}" = "zip" ]; then
    # According to https://unix.stackexchange.com/q/2690, zip files cannot be read
    # through a pipe. We'll have to do our own file-based setup.
    tmpfile="$(get_tmpfile "${EXT}")"
    fetch "${URL}" >"${tmpfile}"
    ${sudo} unzip "${tmpfile}" -d "${BIN_DIR}"
    rm "${tmpfile}"
  else
    error "Unknown package extension."
    info "This almost certainly results from a bug in this script--please file a"
    info "bug report at https://github.com/starship/starship/issues"
    exit 1
  fi
}

elevate_priv() {
  if ! hash sudo 2>/dev/null; then
    error 'Could not find the command "sudo", needed to get permissions for install.'
    info "If you are on Windows, please run your shell as an administrator, then"
    info "rerun this script. Otherwise, please run this script as root, or install"
    info "sudo."
    exit 1
  fi
  if ! sudo -v; then
    error "Superuser not granted, aborting installation"
    exit 1
  fi
}

install() {
  local msg
  local sudo

  if test_writeable "${BIN_DIR}"; then
    sudo=""
    msg="Installing Starship, please wait…"
  else
    warn "Escalated permissions are required to install to ${BIN_DIR}"
    elevate_priv
    sudo="sudo"
    msg="Installing Starship as root, please wait…"
  fi
  info "$msg"
  fetch_and_unpack "${sudo}"
}

# Currently supporting:
#   - win (Git Bash)
#   - darwin
#   - linux
#   - linux_musl (Alpine)
detect_platform() {
  local platform
  platform="$(uname -s | tr '[:upper:]' '[:lower:]')"

  # check for MUSL
  if [ "${platform}" = "linux" ]; then
    if ldd /bin/sh | grep -i musl >/dev/null; then
      platform=unknown-linux-musl
    fi
  fi

  # mingw is Git-Bash
  if echo "${platform}" | grep -i mingw >/dev/null; then
    platform=pc-windows-msvc
  fi

  if [ "${platform}" = "linux" ]; then
    platform=unknown-linux-gnu
  fi

  if [ "${platform}" = "darwin" ]; then
    platform=apple-darwin
  fi

  echo "${platform}"
}

# Currently supporting:
#   - x86_64
#   - i386
detect_arch() {
  local arch
  arch="$(uname -m | tr '[:upper:]' '[:lower:]')"

  # `uname -m` in some cases mis-reports 32-bit OS as 64-bit, so double check
  if [ "${arch}" = "x64" ] && [ "$(getconf LONG_BIT)" -eq 32 ]; then
    arch=i386
  fi

  echo "${arch}"
}

confirm() {
  if [ -z "${FORCE-}" ]; then
    printf "%s " "${MAGENTA}?${NO_COLOR} $* ${BOLD}[y/N]${NO_COLOR}"
    set +e
    read -r yn </dev/tty
    rc=$?
    set -e
    if [ $rc -ne 0 ]; then
      error 'Error reading from prompt (please re-run with the `--yes` option)'
      exit 1
    fi
    if [ "$yn" != "y" ] && [ "$yn" != "yes" ]; then
      error 'Aborting (please answer "yes" to continue)'
      exit 1
    fi
  fi
}

check_bin_dir() {
  local bin_dir="$1"

  if [ ! -d "$BIN_DIR" ]; then
    error "Installation location $BIN_DIR does not appear to be a directory"
    info "Make sure the location exists and is a directory, then try again."
    exit 1
  fi

  # https://stackoverflow.com/a/11655875
  local good
  good=$(
    IFS=:
    for path in $PATH; do
      if [ "${path}" = "${bin_dir}" ]; then
        echo 1
        break
      fi
    done
  )

  if [ "${good}" != "1" ]; then
    warn "Bin directory ${bin_dir} is not in your \$PATH"
  fi
}

# defaults
if [ -z "${PLATFORM-}" ]; then
  PLATFORM="$(detect_platform)"
fi

if [ -z "${BIN_DIR-}" ]; then
  BIN_DIR=/usr/local/bin
fi

if [ -z "${ARCH-}" ]; then
  ARCH="$(detect_arch)"
fi

if [ -z "${BASE_URL-}" ]; then
  BASE_URL="https://github.com/starship/starship/releases"
fi

# parse argv variables
while [ "$#" -gt 0 ]; do
  case "$1" in
  -p | --platform)
    PLATFORM="$2"
    shift 2
    ;;
  -b | --bin-dir)
    BIN_DIR="$2"
    shift 2
    ;;
  -a | --arch)
    ARCH="$2"
    shift 2
    ;;
  -B | --base-url)
    BASE_URL="$2"
    shift 2
    ;;

  -V | --verbose)
    VERBOSE=1
    shift 1
    ;;
  -f | -y | --force | --yes)
    FORCE=1
    shift 1
    ;;

  -p=* | --platform=*)
    PLATFORM="${1#*=}"
    shift 1
    ;;
  -b=* | --bin-dir=*)
    BIN_DIR="${1#*=}"
    shift 1
    ;;
  -a=* | --arch=*)
    ARCH="${1#*=}"
    shift 1
    ;;
  -B=* | --base-url=*)
    BASE_URL="${1#*=}"
    shift 1
    ;;
  -V=* | --verbose=*)
    VERBOSE="${1#*=}"
    shift 1
    ;;
  -f=* | -y=* | --force=* | --yes=*)
    FORCE="${1#*=}"
    shift 1
    ;;

  *)
    error "Unknown option: $1"
    exit 1
    ;;
  esac
done

if [ "${ARCH}" = "i386" ]; then
  error "i386 builds are not yet available for Starship\n"
  info "If you would like to see a build for your configuration,"
  info "please create an issue requesting a build for ${MAGENTA}${ARCH}-${PLATFORM}${NO_COLOR}:"
  info "${BOLD}${UNDERLINE}https://github.com/starship/starship/issues/new/${NO_COLOR}\n"
  exit 1
fi

printf "  %s\n" "${UNDERLINE}Configuration${NO_COLOR}"
info "${BOLD}Bin directory${NO_COLOR}: ${GREEN}${BIN_DIR}${NO_COLOR}"
info "${BOLD}Platform${NO_COLOR}:      ${GREEN}${PLATFORM}${NO_COLOR}"
info "${BOLD}Arch${NO_COLOR}:          ${GREEN}${ARCH}${NO_COLOR}"

# non-empty VERBOSE enables verbose untarring
if [ -n "${VERBOSE-}" ]; then
  VERBOSE=v
  info "${BOLD}Verbose${NO_COLOR}: yes"
else
  VERBOSE=
fi

echo

EXT=tar.gz
if [ "${PLATFORM}" = "pc-windows-msvc" ]; then
  EXT=zip
fi

URL="${BASE_URL}/latest/download/starship-${ARCH}-${PLATFORM}.${EXT}"
info "Tarball URL: ${UNDERLINE}${BLUE}${URL}${NO_COLOR}"
confirm "Install Starship ${GREEN}latest${NO_COLOR} to ${BOLD}${GREEN}${BIN_DIR}${NO_COLOR}?"
check_bin_dir "${BIN_DIR}"

install
complete "Starship installed"

echo
info "Please follow the steps for your shell to complete the installation:

  ${BOLD}${UNDERLINE}Bash${NO_COLOR}
  Add the following to the end of ${BOLD}~/.bashrc${NO_COLOR}:

      eval \"\$(starship init bash)\"

  ${BOLD}${UNDERLINE}Fish${NO_COLOR}
  Add the following to the end of ${BOLD}~/.config/fish/config.fish${NO_COLOR}:

      starship init fish | source

  ${BOLD}${UNDERLINE}Zsh${NO_COLOR}
  Add the following to the end of ${BOLD}~/.zshrc${NO_COLOR}:

      eval \"\$(starship init zsh)\"

  ${BOLD}${UNDERLINE}Ion${NO_COLOR}
  Add the following to the end of ${BOLD}~/.config/ion/initrc${NO_COLOR}:

      eval \$(starship init ion)
"