#!/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.
# goimports is installed via `go install` at a pinned commit (never
# "latest"), unless the installed one already has the pinned version.
# The linter is not installed: it runs only as the lint phase of the
# Dockerfile.
set -eu

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

# Pinned versions, 2026-10-05
# GOIMPORTS_REF is the commit tagged GOIMPORTS_VERSION.
GOIMPORTS_VERSION="v0.42.0"
GOIMPORTS_REF="golang.org/x/tools/cmd/goimports@009367f5c17a8d4c45a961a3a509277190a9a6f0"

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
}

# Print the version the goimports on PATH was built from, or nothing.
# goimports has no version flag; `go version -m` reads the binary's
# build info, whose "mod" line names the module and its version.
goimports_version() {
    if missing goimports; then return 0; fi
    go version -m "$(command -v goimports)" 2>/dev/null |
        awk '$1 == "mod" { print $3 }'
}

ensure_goimports() {
    if [ "$(goimports_version)" = "$GOIMPORTS_VERSION" ]; then
        echo "goimports $GOIMPORTS_VERSION already installed"
        return 0
    fi
    go install "$GOIMPORTS_REF"
    hash -r
    if [ "$(goimports_version)" != "$GOIMPORTS_VERSION" ]; then
        echo "bootstrap: goimports on PATH is not $GOIMPORTS_VERSION:" \
            "$(command -v goimports)" >&2
        exit 1
    fi
    echo "goimports $GOIMPORTS_VERSION installed"
}

main() {
    cd "$ROOT"

    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

    # go install writes to Go's bin directory, which need not be on PATH.
    gobin="$(go env GOBIN)"
    [ -n "$gobin" ] || gobin="$(go env GOPATH)/bin"
    PATH="$gobin:$PATH"
    ensure_goimports

    go mod download

    echo "bootstrap complete"
}

main "$@"
