#!/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). goimports is installed with `go install` at a pinned
# version (integrity via the Go module checksum database) into
# /usr/local/bin so it is on PATH. The linter is not installed here: it
# runs only in Docker via script/lint, so docker is its sole prerequisite.
set -eu

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

# Pinned versions. Never "latest"; exact versions only.
# golang.org/x/tools goimports, 2026-08-13. v0.49.0 requires Go 1.25 (matches
# go.mod); v0.50.0 needs Go 1.26. Integrity via the Go module checksum database.
GOIMPORTS_VERSION="v0.49.0"

PKGMGR=""
SUDO=""

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) $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
}

# goimports is not packaged uniformly across nix/apt/brew/apk, so install it
# with `go install` at a pinned version and place the binary in /usr/local/bin
# so it is on PATH regardless of shell config. Requires go, which main
# installs first.
ensure_goimports() {
    if ! missing goimports; then return 0; fi
    detect_pkgmgr
    tmp="$(mktemp -d)"
    GOBIN="$tmp" go install "golang.org/x/tools/cmd/goimports@${GOIMPORTS_VERSION}"
    $SUDO install -m 0755 "$tmp/goimports" /usr/local/bin/goimports
    rm -rf "$tmp"
}

main() {
    cd "$ROOT"

    # Base tooling
    if missing git; then pkg_install git git git git; fi
    if missing make; then pkg_install gnumake make make make; fi

    # Go toolchain
    if missing go; then pkg_install go golang go go; fi
    ensure_goimports

    # The linter runs only in Docker (script/lint). Warn, don't fail: the
    # rest of the repo works without it.
    if missing docker; then
        echo "bootstrap: WARNING: docker not found; make lint and" >&2
        echo "bootstrap: make check require it. Install docker to run" >&2
        echo "bootstrap: the linter." >&2
    fi

    go mod download

    echo "bootstrap complete"
}

main "$@"