install

#!/usr/bin/env bash

set -eu
set -o pipefail

EMACS_DIR="${EMACS_DIR:-$HOME/.emacs.d}"
PAIRING_EMACS_REPO="${PAIRING_EMACS_REPO:-https://github.com/totherme/pairing-emacs}"

RED='\033[0;31m'
GREEN='\033[1;32m'
YELLOW='\033[1;33m'
BLUE='\033[1;34m'
NC='\033[0m'    # No Colour


main() {
    info "Attempting to clone pairing-emacs..."
    get_git_repo "$PAIRING_EMACS_REPO" "$EMACS_DIR"
    info "Attempting to install golang tooling..."
    optionally_get_go_tools
    info "Attempting to install tmux config..."
    install_tmux_config_from "${EMACS_DIR}/tmux.conf"

    echo -e "${GREEN}DONE${NC}: See ${EMACS_DIR}/README.md for how to use this emacs setup."
}

get_git_repo() {
    local git_repo target_dir
    git_repo="${1:?Expected git_repo in get_git_repo}"
    target_dir="${2:?Expected target_dir in get_git_repo}"

    if ! which git 2>/dev/null >/dev/null ; then
	fail "You don't seem to have git in your \$PATH. You'll need it to clone the pairing-emacs repo."
    fi

    if [[ -e "$target_dir" ]] ; then
	warn "Found existing ${target_dir}. Backing it up."
	backup_and_remove "$target_dir"
    fi
    git clone --recurse-submodules -q "$git_repo" "$target_dir"
}

backup_and_remove() {
    local file backup i
    file="${1:?Expected file name in backup_and_remove}"

    shopt -s extglob		# Strip trailing '/' chars
    file="${file%%+(/)}"

    if [[ ! -e "$file" ]] ; then
	return
    fi

    backup="${file}.backup"
    i=1
    while [[ -e "$backup" ]] ; do
	backup="${file}.backup.${i}"
	(( i++ ))
    done

    mv "$file" "$backup"
}

optionally_get_go_tools() {
    if ! which go 2> /dev/null > /dev/null ; then
	warn "You don't seem to have go. Skipping installing the go tools."
	return 0
    fi

    if [[ -z "$GOPATH" ]] ; then
	warn "You don't seem to have a \$GOPATH set up. Skipping installing the go tools."
	return 0
    fi

    go get -u golang.org/x/tools/cmd/goimports \
       github.com/rogpeppe/godef \
       github.com/nsf/gocode \
       github.com/dougm/goflymake
}

install_tmux_config_from() {
    local source target
    source="${1:?Expected source path in install_tmux_config_from}"
    target="${HOME}/.tmux.conf"

    if [[ -e "$target" ]] ; then
	warn "Found an existing \$HOME/.tmux.conf. Backing it up."
	backup_and_remove "$target"
    fi

    ln -s "$source" "$target"
}

fail() {
    echo -e "${RED}FAIL${NC}:" "$@" >&2
    exit 1
}

warn() {
    echo -e "${YELLOW}WARNING${NC}:" "$@" >&2
}

info() {
    echo -e "${BLUE}INFO${NC}:" "$@"
}

if [[ ! -z "${TESTS_ONLY:-}" ]] ; then
    #  We're in a test harness. Don't do anything side-effecting. Just
    #  load the functions for unit testing.
    return 0
fi

main