#!/usr/bin/env bash
set -euo pipefail

########################################
# Forgejo Updater
# curl | bash safe
########################################

TTY="/dev/tty"

BOLD="\033[1m"
GREEN="\033[32m"
YELLOW="\033[33m"
RED="\033[31m"
BLUE="\033[34m"
RESET="\033[0m"

section() { printf "\n${BLUE}${BOLD}==> %s${RESET}\n" "$*"; }
say()     { printf "${GREEN}✔ %s${RESET}\n" "$*"; }
warn()    { printf "${YELLOW}⚠ %s${RESET}\n" "$*"; }
err()     { printf "${RED}✖ %s${RESET}\n" "$*"; }

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

need_tty() {
  if [[ ! -r "$TTY" || ! -w "$TTY" ]]; then
    # No TTY (e.g. non-interactive CI) — that's fine as long as -y was passed.
    return 1
  fi
  return 0
}

prompt() {
  local msg="$1" out
  printf "${BOLD}%s${RESET}" "$msg" >"$TTY"
  IFS= read -r out <"$TTY"
  printf "%s" "$out"
}

confirm_default_no() {
  local msg="$1" ans
  if $ASSUME_YES; then
    return 0
  fi
  if ! need_tty; then
    err "No TTY and -y not given — refusing to guess on: $msg"
    exit 1
  fi
  ans="$(prompt "$msg [y/N]: ")"
  [[ "${ans,,}" == "y" || "${ans,,}" == "yes" ]]
}

require_root_or_sudo() {
  if [[ "${EUID:-$(id -u)}" -ne 0 ]]; then
    if have sudo; then
      SUDO="sudo"
    else
      err "Root or sudo required."
      exit 1
    fi
  else
    SUDO=""
  fi
}

run_with_spinner() {
  local label="$1"; shift
  ("$@") &
  local pid=$! spin='|/-\' i=0
  printf "\033[?25l" >"$TTY" 2>/dev/null || true
  while kill -0 "$pid" 2>/dev/null; do
    i=$(( (i + 1) % 4 ))
    printf "\r${BLUE}${BOLD}..${RESET} %s %s" "${spin:$i:1}" "$label" >"$TTY" 2>/dev/null || true
    sleep 0.12
  done
  wait "$pid"; local rc=$?
  printf "\r\033[K" >"$TTY" 2>/dev/null || true
  printf "\033[?25h" >"$TTY" 2>/dev/null || true
  return "$rc"
}

########################################
# Args
########################################
ASSUME_YES=false
INSTALL_PATH="/usr/local/bin/forgejo"
SERVICE_NAME="forgejo"
VERSION=""

usage() {
  cat <<EOF
Usage: $0 [-y] [-p install_path] [-s service_name] <version>

  -y               Assume yes to all prompts (non-interactive)
  -p PATH          Install path (default: /usr/local/bin/forgejo)
  -s NAME          systemd service name (default: forgejo)

Example: $0 11.0.10
EOF
}

while getopts ":yp:s:h" opt; do
  case "$opt" in
    y) ASSUME_YES=true ;;
    p) INSTALL_PATH="$OPTARG" ;;
    s) SERVICE_NAME="$OPTARG" ;;
    h) usage; exit 0 ;;
    *) usage; exit 1 ;;
  esac
done
shift $((OPTIND - 1))

VERSION="${1:-}"
if [[ -z "$VERSION" ]]; then
  usage
  exit 1
fi
# Strip an accidental leading "v" so both "11.0.10" and "v11.0.10" work.
VERSION="${VERSION#v}"

need_tty || true
require_root_or_sudo

########################################
# Dependency check
########################################
section "Checking dependencies"
for bin in curl systemctl sha256sum install; do
  have "$bin" || { err "Required tool '$bin' not found."; exit 1; }
done
say "All required tools present"

########################################
# Arch detection
########################################
case "$(uname -m)" in
  x86_64|amd64)   ARCH="amd64" ;;
  aarch64|arm64)  ARCH="arm64" ;;
  armv7l|armv6l)  ARCH="arm-6" ;;
  *)
    err "Unsupported architecture: $(uname -m)"
    exit 1
    ;;
esac

BINARY="forgejo-${VERSION}-linux-${ARCH}"
BASE_URL="https://codeberg.org/forgejo/forgejo/releases/download/v${VERSION}"

########################################
# Sanity checks before touching anything
########################################
if ! systemctl list-unit-files "${SERVICE_NAME}.service" >/dev/null 2>&1; then
  warn "systemd unit '${SERVICE_NAME}.service' not found — will still attempt but stop/start may fail."
fi

WORKDIR="$(mktemp -d)"
cleanup() { rm -rf "$WORKDIR"; }
trap cleanup EXIT

########################################
# Download
########################################
section "Downloading Forgejo ${VERSION} (${ARCH})"

if ! run_with_spinner "Downloading binary..." \
  curl -fL --retry 3 --retry-delay 2 -o "${WORKDIR}/${BINARY}" "${BASE_URL}/${BINARY}"; then
  err "Download failed. Check the version number and your network connection."
  exit 1
fi
say "Downloaded ${BINARY}"

########################################
# Checksum verification (best-effort; Forgejo publishes .sha256 sidecars)
########################################
section "Verifying checksum"

if curl -fsSL -o "${WORKDIR}/${BINARY}.sha256" "${BASE_URL}/${BINARY}.sha256" 2>/dev/null; then
  ( cd "$WORKDIR" && sha256sum -c "${BINARY}.sha256" ) || {
    err "Checksum verification FAILED. Refusing to install a corrupted/tampered binary."
    exit 1
  }
  say "Checksum verified"
else
  warn "No checksum file found upstream — skipping verification."
  if ! confirm_default_no "Continue without checksum verification?"; then
    err "Aborted by user."
    exit 1
  fi
fi

chmod +x "${WORKDIR}/${BINARY}"

########################################
# Validate the binary actually runs before going anywhere near the service
########################################
section "Validating binary"
if ! "${WORKDIR}/${BINARY}" --version >/dev/null 2>&1; then
  err "Downloaded binary failed to execute (--version check). Aborting before touching the running service."
  exit 1
fi
say "Binary runs OK: $("${WORKDIR}/${BINARY}" --version 2>&1 | head -n1)"

########################################
# Backup current binary
########################################
BACKUP=""
if [[ -f "$INSTALL_PATH" ]]; then
  BACKUP="${INSTALL_PATH}.bak.$(date +%Y%m%d%H%M%S)"
  $SUDO cp -a "$INSTALL_PATH" "$BACKUP"
  say "Backed up existing binary to ${BACKUP}"
fi

########################################
# Confirm before disrupting the service
########################################
section "Ready to install"
echo "  Version:  ${VERSION}"
echo "  Path:     ${INSTALL_PATH}"
echo "  Service:  ${SERVICE_NAME}"
if ! confirm_default_no "Stop '${SERVICE_NAME}', replace the binary, and restart?"; then
  err "Aborted by user. Nothing was changed."
  exit 1
fi

########################################
# Stop, swap (atomically), start
########################################
section "Installing"

$SUDO systemctl stop "${SERVICE_NAME}" || warn "Failed to stop ${SERVICE_NAME} (continuing anyway)"

# `install` does an atomic rename into place rather than an in-place copy,
# so there's never a half-written binary on disk.
$SUDO install -m 0755 "${WORKDIR}/${BINARY}" "$INSTALL_PATH"
say "Installed new binary to ${INSTALL_PATH}"

$SUDO systemctl start "${SERVICE_NAME}" || true

section "Verifying service"
sleep 2
if $SUDO systemctl is-active --quiet "${SERVICE_NAME}"; then
  say "${SERVICE_NAME} is active and running"
else
  err "${SERVICE_NAME} failed to start after update!"
  if [[ -n "$BACKUP" ]]; then
    warn "Rolling back to previous binary..."
    $SUDO install -m 0755 "$BACKUP" "$INSTALL_PATH"
    $SUDO systemctl restart "${SERVICE_NAME}" || true
    if $SUDO systemctl is-active --quiet "${SERVICE_NAME}"; then
      say "Rollback successful — service restored to previous version"
    else
      err "Rollback also failed — manual intervention required. Backup at: ${BACKUP}"
    fi
  else
    err "No backup was available to roll back to. Check 'systemctl status ${SERVICE_NAME}' and journalctl."
  fi
  exit 1
fi

section "Done"
say "Forgejo updated to ${VERSION}"