#!/bin/sh
# gabeforge installer.
#
#   curl -fsSL https://get.gabeforge.com | sh
#
# Signs you in by email, downloads the release for this OS, checks its sha256, and
# installs it for your user only: no sudo, nothing outside your home directory.
#
#   ~/.local/share/gabeforge/   the release (binary, pi's files, harness, companion)
#   ~/.local/bin/gabeforge      a link to the binary
#   ~/.gabeforge/               settings, sessions, and your sign-in token (0600)
#
# The token never appears in a URL, a command line or your shell history: it goes
# from the sign-in reply straight into ~/.gabeforge/token, and curl reads the
# Authorization header from a private config file.
set -eu

ACCOUNTS="${GABEFORGE_ACCOUNTS_URL:-https://accounts.gabeforge.com}"
PREFIX="${GABEFORGE_PREFIX:-$HOME/.local/share/gabeforge}"
BIN_DIR="${GABEFORGE_BIN_DIR:-$HOME/.local/bin}"
CONF="${GABEFORGE_HOME:-$HOME/.gabeforge}"

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

for tool in curl tar uname sed mktemp; do
  command -v "$tool" >/dev/null 2>&1 || die "needs $tool"
done
if command -v sha256sum >/dev/null 2>&1; then SHA="sha256sum"
elif command -v shasum >/dev/null 2>&1; then SHA="shasum -a 256"
else die "needs sha256sum or shasum"; fi

# Piped into sh, stdin is this script: questions go to the terminal instead.
[ -r /dev/tty ] || die "run it in a terminal (it asks for your email)"

case "$(uname -s)" in
  Linux) os=linux ;;
  Darwin) os=darwin ;;
  *) die "unsupported OS $(uname -s); Linux and macOS for now" ;;
esac
case "$(uname -m)" in
  x86_64|amd64) arch=x64 ;;
  aarch64|arm64) arch=arm64 ;;
  *) die "unsupported CPU $(uname -m)" ;;
esac
if [ "$os" = linux ] && ldd --version 2>&1 | grep -qi musl; then
  die "musl-based Linux (Alpine) is not supported yet"
fi
if [ "$os" = darwin ] && [ -z "${GABEFORGE_PREFIX:-}" ]; then
  PREFIX="$HOME/Library/Application Support/gabeforge"
fi
TARGET="$os-$arch"

umask 077
TMP="$(mktemp -d)"
trap 'rm -rf "$TMP"' EXIT INT TERM
mkdir -p "$CONF"

# json_get KEY FILE: the string value of a top-level key in a one-line JSON reply.
json_get() { sed -n "s/.*\"$1\":\"\\([^\"]*\\)\".*/\\1/p" "$2"; }
json_num() { sed -n "s/.*\"$1\":\\([0-9]*\\).*/\\1/p" "$2"; }

auth_conf() {
  # curl reads the header from here, so the token is never in curl's argv.
  printf 'header = "Authorization: Bearer %s"\n' "$(cat "$CONF/token")" > "$TMP/auth.conf"
}

signed_in() {
  [ -s "$CONF/token" ] || return 1
  auth_conf
  curl -fsS -K "$TMP/auth.conf" "$ACCOUNTS/v1/me" -o "$TMP/me.json" 2>/dev/null
}

sign_in() {
  printf 'Email you paid with on Ko-fi (or will sign in with): ' > /dev/tty
  read -r email < /dev/tty
  [ -n "$email" ] || die "no email given"
  printf '{"email":"%s","client":"cli","label":"%s"}' \
    "$(printf '%s' "$email" | sed 's/["\\]//g')" "$(uname -n | sed 's/["\\]//g')" > "$TMP/start.req"
  curl -fsS -H 'Content-Type: application/json' --data @"$TMP/start.req" "$ACCOUNTS/device/start" -o "$TMP/start.json" \
    || die "could not start sign-in (check the address, or try again in a few minutes)"
  code="$(json_get user_code "$TMP/start.json")"
  interval="$(json_num interval "$TMP/start.json")"; interval="${interval:-3}"
  expires="$(json_num expires_in "$TMP/start.json")"; expires="${expires:-900}"
  # The device code is a secret too: it goes in a request body read from a file.
  printf '{"device_code":"%s"}' "$(json_get device_code "$TMP/start.json")" > "$TMP/poll.req"
  say ""
  say "Sent a sign-in link to $email."
  say "Open it and check it shows this code:  $code"
  say ""
  printf 'Waiting for you to confirm'
  waited=0
  while [ "$waited" -lt "$expires" ]; do
    sleep "$interval"; waited=$((waited + interval))
    curl -fsS -H 'Content-Type: application/json' --data @"$TMP/poll.req" "$ACCOUNTS/device/poll" -o "$TMP/poll.json" || continue
    case "$(json_get status "$TMP/poll.json")" in
      ok)
        json_get token "$TMP/poll.json" > "$CONF/token.new"
        chmod 600 "$CONF/token.new" && mv "$CONF/token.new" "$CONF/token"
        rm -f "$TMP/poll.json"
        say ""
        return 0 ;;
      denied) say ""; die "sign-in was denied on the link page" ;;
      expired) break ;;
    esac
    printf '.'
  done
  say ""
  die "the sign-in link expired; run the installer again"
}

if signed_in; then
  say "Signed in as $(json_get email "$TMP/me.json")."
else
  sign_in
  auth_conf
fi

say "Fetching the $TARGET release…"
status="$(curl -sS -K "$TMP/auth.conf" -H 'Content-Type: application/json' --data "{\"target\":\"$TARGET\"}" \
  "$ACCOUNTS/v1/download" -o "$TMP/release.json" -w '%{http_code}')" || die "cannot reach $ACCOUNTS"
[ "$status" = 200 ] || die "$(json_get error "$TMP/release.json")"
url="$(json_get url "$TMP/release.json")"
want="$(json_get sha256 "$TMP/release.json")"
version="$(json_get version "$TMP/release.json")"
[ -n "$url" ] && [ -n "$want" ] || die "no release for $TARGET: $(json_get error "$TMP/release.json")"
curl -fL --progress-bar "$url" -o "$TMP/gabeforge.tar.gz" || die "download failed"
got="$($SHA "$TMP/gabeforge.tar.gz" | cut -d' ' -f1)"
[ "$got" = "$want" ] || die "checksum mismatch: got $got, expected $want"

# Unpack beside the install dir, then swap whole trees.
parent="$(dirname "$PREFIX")"
mkdir -p "$parent"
stage="$(mktemp -d "$parent/.gabeforge-new-XXXXXX")"
tar -xzf "$TMP/gabeforge.tar.gz" -C "$stage"
[ -x "$stage/gabeforge/gabeforge" ] || die "release is missing its binary"
if [ -e "$PREFIX" ]; then
  mv "$PREFIX" "$stage/old"
fi
mv "$stage/gabeforge" "$PREFIX"
rm -rf "$stage"
chmod 755 "$PREFIX"

mkdir -p "$BIN_DIR"
ln -sf "$PREFIX/gabeforge" "$BIN_DIR/gabeforge"
say "Installed gabeforge $version in $PREFIX."

# First run: which model it talks to, and whether the phone can start sessions here.
"$PREFIX/gabeforge" setup < /dev/tty || true
if [ "$os" = linux ] && command -v systemctl >/dev/null 2>&1 && systemctl --user show-environment >/dev/null 2>&1; then
  printf '\nLet your phone start sessions on this machine (runs in the background)? [Y/n] ' > /dev/tty
  read -r ans < /dev/tty || ans=n
  case "$ans" in n|N|no|No) ;; *) "$PREFIX/gabeforge" host --install || true ;; esac
fi

case ":$PATH:" in
  *":$BIN_DIR:"*) say ""; say "Run: gabeforge" ;;
  *) say ""; say "Add $BIN_DIR to your PATH, then run: gabeforge" ;;
esac