#!/bin/sh
# git has to exist before chezmoi fetches the six git-repo externals.
#
# The documented first command is
#
#     sh -c "$(curl -fsLS get.chezmoi.io)" -- init --apply <url>
#
# and on a stock box it used to fail here:
#
#     chezmoi: .config/tmux/plugins/tpm: exec: "git": executable file not found
#
# chezmoi itself is a static download and installs fine. git is a different
# matter: Ubuntu Server cloud images, the Ubuntu docker image and WSL Ubuntu all
# ship curl and none of them ship git. So the front door of the whole system
# did not open on the most ordinary kind of fresh machine there is.
#
# `run_before_` is the fix rather than a README note, because chezmoi runs these
# before every other target -- externals included. Verified, not assumed: a
# probe script printed "git ABSENT here" and the external failed immediately
# after, in that order.
#
# This exits in microseconds on every machine that already has git, which after
# the first apply is all of them.
set -eu

command -v git >/dev/null 2>&1 && exit 0

printf 'chezmoi: git is required for the shell externals and is not installed.\n' >&2

# Root needs no sudo; a non-root user without sudo cannot do this at all, and
# should be told rather than shown a package manager error.
if [ "$(id -u)" -eq 0 ]; then
	SUDO=
elif command -v sudo >/dev/null 2>&1; then
	SUDO=sudo
else
	printf 'chezmoi: cannot install it -- not root and no sudo. Install git and re-run:\n' >&2
	printf 'chezmoi:   chezmoi init --apply <url>\n' >&2
	exit 1
fi

printf 'chezmoi: installing git...\n' >&2
if   command -v apt-get >/dev/null 2>&1; then
	${SUDO} env DEBIAN_FRONTEND=noninteractive apt-get update -qq || :
	${SUDO} env DEBIAN_FRONTEND=noninteractive apt-get install -y -qq git
elif command -v dnf     >/dev/null 2>&1; then ${SUDO} dnf install -y git
elif command -v yum     >/dev/null 2>&1; then ${SUDO} yum install -y git
elif command -v pacman  >/dev/null 2>&1; then ${SUDO} pacman -Sy --noconfirm git
elif command -v zypper  >/dev/null 2>&1; then ${SUDO} zypper --non-interactive install git
elif command -v apk     >/dev/null 2>&1; then ${SUDO} apk add --no-cache git
elif command -v brew    >/dev/null 2>&1; then brew install git
elif [ "$(uname -s)" = Darwin ]; then
	# On macOS `git` is a stub that triggers the Command Line Tools installer,
	# which is a GUI dialog -- there is nothing useful to do unattended.
	printf 'chezmoi: run `xcode-select --install`, then re-run chezmoi init --apply.\n' >&2
	exit 1
else
	printf 'chezmoi: no package manager I recognise. Install git and re-run.\n' >&2
	exit 1
fi

command -v git >/dev/null 2>&1 \
	|| { printf 'chezmoi: git still not on PATH after installing it.\n' >&2; exit 1; }
printf 'chezmoi: git %s installed.\n' "$(git --version | awk '{print $3}')" >&2