install

#!/bin/bash -e

fail() {
  >&2 cat
  exit 1
}

if [ $# -ne 0 ]; then
  fail << EOF
Usage: ${0##*/}

Options:

  HTTPS=0|1
  AUTO_COMPLETION=1|0
  CONFIRM=0|1

Installs cppsm command by cloning its repository and appending the necessary
changes to the user's Bash startup script.
EOF
fi

if [ -e "$HOME/.cppsm" ]; then
  fail << EOF
ERROR: .cppsm already exists in your \$HOME.
EOF
fi

contains() {
  local PATTERN="$1"
  local FILE="$2"
  [ -e "$FILE" ] && grep -q -e "$PATTERN" "$FILE"
}

for SCRIPT in .bash_profile .bashrc; do
  if contains CPPSM "$HOME/$SCRIPT"; then
    fail << EOF
ERROR: CPPSM already appears in your $SCRIPT.
EOF
  fi
  if [ -e "$HOME/$SCRIPT" ]; then
    TARGET_SCRIPT="$SCRIPT"
  fi
done

if [ -z "$TARGET_SCRIPT" ]; then
  fail << EOF
ERROR: Neither .bash_profile nor .bashrc exists.
EOF
fi

COMMANDS="$(cat << EOF
CPPSM="\$HOME/.cppsm"
export PATH="\$CPPSM/bin:\$PATH"
EOF
)"

if [ "$AUTO_COMPLETION" != 0 ]; then
  COMMANDS="$(cat << EOF
$COMMANDS
. "\$CPPSM/bash_completion"
EOF
)"
fi

SNIPPET="$(cat << EOF
# CPPSM lines added by the C++ submodule manager 'install' script.
# Uninstall by deleting the CPPSM lines and the \$CPPSM directory.
$COMMANDS
EOF
)"

if [ "$HTTPS" = 1 ] || [ "$TRAVIS" = true ]; then
  URL="https://github.com/cppsm/cppsm-cli.git"
else
  URL="git@github.com:cppsm/cppsm-cli.git"
fi

# shellcheck disable=2001
cat << EOF
This will install the C++ submodule manager 'cppsm' command by running

  git clone --quiet --single-branch $URL "\$HOME/.cppsm"

and appending

$(echo "$SNIPPET" | sed 's#^#  #')

to \$HOME/$TARGET_SCRIPT.

EOF

if [ "$CONFIRM" = 1 ]; then
  read -p "Continue (y/n)? " -n 1 -r && echo
  if ! [[ $REPLY =~ ^[Yy]$ ]]; then
    fail <<EOF
Installation cancelled.
EOF
  fi
  echo
fi

if ! git clone --quiet --single-branch $URL "$HOME/.cppsm"; then
  fail << EOF
ERROR: Failed to git clone the cppsm-cli.
EOF
fi

augment-script() {
  cat << EOF >> "$HOME/$TARGET_SCRIPT"

$SNIPPET
EOF
}

if ! augment-script; then
  fail <<EOF
ERROR: Failed to append to \$HOME/$TARGET_SCRIPT.
EOF
fi

cat <<EOF
C++ submodule manager 'cppsm' command has been installed!

To use the 'cppsm' command you now need to restart the shell or execute the
following commands in this shell:

$COMMANDS
EOF