#!/bin/sh
# script/bootstrap: install all dependencies needed to build and develop
# this repo. Idempotent: every install is guarded by a check so already
# installed tools are skipped. Base tooling comes from nix, apt, brew,
# or apk (detected in that order); assumes nothing is present (not git,
# make, or go). Neither the linter nor the Markdown formatter is
# installed: golangci-lint (script/lint) and prettier (script/fmt,
# script/fmt-check) run via docker only, pinned by hash, so their only
# prerequisite is a working docker — which is warned about, not
# installed, because everything except linting and formatting works
# without it.
set -eu

ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"

PKGMGR=""
SUDO=""
APT_UPDATED=""

detect_pkgmgr() {
    [ -n "$PKGMGR" ] && return 0
    if command -v nix-env >/dev/null 2>&1; then
        PKGMGR="nix"
    elif command -v apt-get >/dev/null 2>&1; then
        PKGMGR="apt"
    elif command -v brew >/dev/null 2>&1; then
        PKGMGR="brew"
    elif command -v apk >/dev/null 2>&1; then
        PKGMGR="apk"
    else
        echo "bootstrap: no supported package manager (nix, apt, brew, apk)" >&2
        exit 1
    fi
    if [ "$PKGMGR" = "apt" ]; then
        export DEBIAN_FRONTEND=noninteractive
        if [ "$(id -u)" != "0" ]; then
            SUDO="sudo"
        fi
    fi
}

# pkg_install <nix-attr> <apt-pkg> <brew-formula> <apk-pkg>
pkg_install() {
    detect_pkgmgr
    case "$PKGMGR" in
        nix) nix-env -iA "nixpkgs.$1" ;;
        apt)
            if [ -z "$APT_UPDATED" ]; then
                $SUDO env DEBIAN_FRONTEND=noninteractive apt-get update
                APT_UPDATED=1
            fi
            $SUDO env DEBIAN_FRONTEND=noninteractive apt-get install -y "$2"
            ;;
        brew) brew install "$3" ;;
        apk) apk add --no-cache "$4" ;;
    esac
}

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

main() {
    cd "$ROOT"

    # System tooling, deliberately unpinned: these come from the host
    # package manager and whatever version it ships is what the host
    # gets, so a presence check is the right check. The repo pins no
    # system toolchain versions — the Go language version is governed by
    # go.mod, and builds that must be reproducible run in the Docker
    # image, whose base images are pinned by digest.
    if missing git; then pkg_install git git git git; fi
    if missing make; then pkg_install gnumake make make make; fi
    if missing go; then pkg_install go golang go go; fi

    # Linting and Markdown formatting run via docker only, so docker is
    # their prerequisite rather than something bootstrap installs. Warn,
    # do not fail: everything except `make lint`, `make fmt` and
    # `make fmt-check` — and, through them, `make check`, `make docker`
    # and the pre-commit hook — works without it.
    if missing docker; then
        echo "bootstrap: WARNING: docker not found; make lint, make fmt," >&2
        echo "bootstrap: make fmt-check, make check and make docker" >&2
        echo "bootstrap: require it." >&2
    fi

    go mod download

    echo "bootstrap complete"
}

main "$@"