#!/usr/bin/env bash
# Install or upgrade CST-Agent on Linux, WSL or macOS. Safe to rerun: an
# existing checkout is fast-forwarded, rebuilt and reinstalled.
#
#   bootstrap_linux.sh [DIR] [--no-pull]
#   cst-agent-update            (installed by this script; same as rerunning it)
#
# Env: CST_AGENT_PREFIX (install prefix, default ~/.local), CST_AGENT_DIR
# (checkout, default: current checkout or ~/CST-agent), CST_AGENT_REPO.
set -euo pipefail

deps_hint() {
  echo "==> deps: gcc/clang make pkg-config libcurl ncursesw"
  if [[ "$(uname -s)" == Darwin ]]; then
    echo "    macOS: xcode-select --install && brew install ncurses curl pkg-config"
  elif command -v pacman >/dev/null 2>&1; then
    echo "    Arch: sudo pacman -S --needed base-devel curl ncurses"
  elif command -v apt-get >/dev/null 2>&1; then
    echo "    Debian/Ubuntu/WSL: sudo apt install build-essential pkg-config libcurl4-openssl-dev libncurses-dev"
  elif command -v dnf >/dev/null 2>&1; then
    echo "    Fedora: sudo dnf install gcc make pkgconf libcurl-devel ncurses-devel"
  elif command -v apk >/dev/null 2>&1; then
    echo "    Alpine: sudo apk add build-base pkgconf curl-dev ncurses-dev"
  fi
}

# On NixOS (outside a nix shell) build inside shell.nix.
run_make() {
  if [[ -z "${IN_NIX_SHELL:-}" ]] && command -v nix-shell >/dev/null 2>&1 &&
    [[ -f shell.nix ]]; then
    nix-shell --run "make $*"
  else
    make "$@"
  fi
}

main() {
  local repo_url="${CST_AGENT_REPO:-https://git.whcself.xyz/WHC/CST-agent.git}"
  local prefix="${CST_AGENT_PREFIX:-$HOME/.local}"
  local dir="" pull=1 changed=0 arg
  for arg in "$@"; do
    case "$arg" in
    --no-pull) pull=0 ;;
    --rebuilt) changed=1 ;; # internal: re-exec after a pull
    -h | --help)
      sed -n '2,9p' "$0"
      return 0
      ;;
    *) dir="$arg" ;;
    esac
  done
  if [[ -z "$dir" ]]; then
    if [[ -n "${CST_AGENT_DIR:-}" ]]; then
      dir="$CST_AGENT_DIR"
    elif [[ -f Makefile && -f src/main.c && -d .git ]]; then
      dir="$(pwd)"
    else
      dir="$HOME/CST-agent"
    fi
  fi

  local old="" new=""
  if [[ ! -f "$dir/Makefile" ]]; then
    echo "==> git clone $repo_url -> $dir"
    git clone "$repo_url" "$dir"
    changed=1
  elif ((pull)); then
    old="$(git -C "$dir" rev-parse HEAD)"
    if git -C "$dir" diff --quiet && git -C "$dir" diff --cached --quiet; then
      echo "==> git pull ($dir)"
      git -C "$dir" pull --ff-only
    else
      echo "warning: $dir has local changes; skipping git pull" >&2
    fi
    new="$(git -C "$dir" rev-parse HEAD)"
    if [[ "$old" != "$new" ]]; then
      echo "    $(git -C "$dir" log --oneline "$old..$new" | wc -l) new commit(s)"
      # The script itself may have changed: continue with the new version.
      exec bash "$dir/scripts/bootstrap_linux.sh" "$dir" --no-pull --rebuilt
    fi
  fi
  cd "$dir"
  dir="$(pwd)"

  local jobs
  jobs="$(nproc 2>/dev/null || sysctl -n hw.ncpu 2>/dev/null || echo 4)"
  echo "==> build"
  if ((changed)); then
    run_make clean >/dev/null 2>&1 || true
  fi
  if ! run_make -j"$jobs"; then
    deps_hint
    return 1
  fi
  run_make check >/dev/null 2>&1 || echo "warning: some tests failed (run 'make check')"

  echo "==> install to $prefix/bin"
  mkdir -p "$prefix/bin"
  run_make install PREFIX="$prefix" >/dev/null
  cat >"$prefix/bin/cst-agent-update" <<EOF
#!$(command -v bash)
export CST_AGENT_PREFIX="\${CST_AGENT_PREFIX:-$prefix}"
exec bash "$dir/scripts/bootstrap_linux.sh" "$dir" "\$@"
EOF
  chmod 0755 "$prefix/bin/cst-agent-update"

  echo
  echo "OK: $("$prefix/bin/cst-agent" --version)"
  case ":$PATH:" in
  *":$prefix/bin:"*) ;;
  *) echo "Add to PATH: export PATH=\"$prefix/bin:\$PATH\"" ;;
  esac
  echo "Run 'cst-agent' inside a project directory; upgrade later with 'cst-agent-update'."
  echo "The first start asks for the provider and its API key and saves them."
}

main "$@"