#!/bin/sh
# =============================================================================
# FermiHDI HD — fetch the installer and check this host
# =============================================================================
#   curl -fsSL https://downloads.fermihdi.io/install.sh | sh
#
# Downloads the installer archive, verifies it against its published SHA-256,
# unpacks it into the current directory, and runs the read-only host inventory
# so you can see what this machine can run before anything is decided.
#
# It changes nothing on the host, needs no root, and does not install packages.
# The only step that changes a host is fermihdi-prepare --apply, which this
# does not run and will not run for you.
# =============================================================================
set -eu

VERSION="${FERMIHDI_VERSION:-2.0.2}"
BASE_URL="${FERMIHDI_BASE_URL:-https://downloads.fermihdi.io}"
ARCHIVE="fermihdi-hd-install-${VERSION}.tar.gz"
DEST="${FERMIHDI_DEST:-$(pwd)}"

say()  { printf '%s\n' "$*"; }
warn() { printf '  ! %s\n' "$*" >&2; }
die()  { printf '\nerror: %s\n' "$*" >&2; exit 1; }

# --- what this script itself needs -------------------------------------------
for tool in curl tar sha256sum; do
    command -v "$tool" >/dev/null 2>&1 || {
        [ "$tool" = sha256sum ] && command -v shasum >/dev/null 2>&1 && continue
        die "$tool is required and was not found."
    }
done
sha256() { command -v sha256sum >/dev/null 2>&1 && sha256sum "$1" | cut -d' ' -f1 || shasum -a 256 "$1" | cut -d' ' -f1; }

say ""
say "FermiHDI HD installer ${VERSION}"
say "─────────────────────────────────────────────────────────────"

# --- fetch --------------------------------------------------------------------
TMP="$(mktemp -d)"
trap 'rm -rf "$TMP"' EXIT INT TERM

say "  fetching ${ARCHIVE}"
curl -fsSL "${BASE_URL}/${ARCHIVE}" -o "${TMP}/${ARCHIVE}" \
    || die "could not download ${BASE_URL}/${ARCHIVE}"

# The checksum is published beside the archive. A download that does not match
# it is not unpacked: a truncated tarball that extracts far enough to look right
# is worse than one that fails here.
if curl -fsSL "${BASE_URL}/${ARCHIVE}.sha256" -o "${TMP}/sum" 2>/dev/null; then
    want="$(cut -d' ' -f1 < "${TMP}/sum")"
    got="$(sha256 "${TMP}/${ARCHIVE}")"
    [ "$want" = "$got" ] || die "checksum mismatch — expected ${want}, got ${got}"
    say "  checksum ok"
else
    warn "no published checksum found; continuing unverified"
fi

# --- unpack -------------------------------------------------------------------
DIR="${DEST}/fermihdi-hd-install-${VERSION}"
[ -e "$DIR" ] && die "${DIR} already exists — move it aside or set FERMIHDI_DEST"
tar xzf "${TMP}/${ARCHIVE}" -C "$DEST"
say "  unpacked into ${DIR}"

# --- check this host ----------------------------------------------------------
say ""
say "Checking this host"
say "─────────────────────────────────────────────────────────────"

missing=""
for tool in python3 docker lsblk lscpu ip findmnt; do
    command -v "$tool" >/dev/null 2>&1 || missing="${missing} ${tool}"
done
python3 -c 'import yaml' >/dev/null 2>&1 || missing="${missing} python3-yaml"

if [ -n "$missing" ]; then
    warn "not installed:${missing}"
    warn "python3 with PyYAML is needed by validate-cluster and fermihdi-prepare;"
    warn "docker by the deploy step. The inventory below runs without them."
    say ""
fi

if [ -x "${DIR}/fermihdi-discover" ]; then
    "${DIR}/fermihdi-discover" || warn "the inventory exited non-zero"
else
    die "fermihdi-discover missing from the archive"
fi

# --- what to do with that -----------------------------------------------------
say ""
say "Next"
say "─────────────────────────────────────────────────────────────"
say "  cd ${DIR}"
say ""
say "  ./fermihdi-configure                    decide what this host runs"
say "  ./validate-cluster cluster.yaml         check that decision"
say "  sudo ./fermihdi-prepare cluster.yaml    show what it would change"
say "  sudo ./fermihdi-prepare cluster.yaml --apply"
say ""
say "  ADMIN_GUIDE.md explains all of it, including what the numbers above mean"
say "  for sizing. The full manual is published rather than packaged:"
say "  ${BASE_URL}/${VERSION}/web/ , or /pdf/ for one printable file."
say ""