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

ROOT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
WORKSPACE_MANIFEST="$ROOT_DIR/Cargo.toml"
CRATE_MANIFEST="$ROOT_DIR/traffic_core/Cargo.toml"
TARGET_BIN="$ROOT_DIR/target/release/awg2-harness"
REBOOT_BIN="$ROOT_DIR/target/release/awg2-reboot-scheduler"
RUST_TOOLCHAIN_FILE="$ROOT_DIR/rust-toolchain.toml"
RUST_TOOLCHAIN_VERSION="1.95.0"

PREPARE_BUILD_ENV=false
PREPARE_RUNTIME_ENV=false
BOOTSTRAP_RUST=false
DO_BUILD=false
PACKAGE=false
INSTALL=false
ENABLE=false
YES=false
SKIP_FMT=false
HAS_ACTION=false

DIST_DIR="$ROOT_DIR/dist"
PACKAGE_VERSION=""

RUN_AS_ROOT=()

BUILD_PACKAGES=(
  ca-certificates
  curl
  build-essential
  pkg-config
  file
  shellcheck
  dpkg-dev
)

RUNTIME_PACKAGES=(
  iproute2
  wireguard-tools
  nftables
  kmod
  util-linux
  procps
  systemd
)

usage() {
  cat <<'EOF'
Usage:
  ./tools/build.sh
  ./tools/build.sh --prepare-build-env --yes
  ./tools/build.sh --prepare-runtime-env --yes
  ./tools/build.sh --bootstrap-rust --yes
  ./tools/build.sh --build
  ./tools/build.sh --package
  ./tools/build.sh --build --package
  ./tools/build.sh --install
  ./tools/build.sh --enable

Flags:
  --prepare-build-env   Install missing build dependencies via apt
  --prepare-runtime-env Install missing runtime dependencies via apt
  --bootstrap-rust      Install rustup/toolchain pinned by this repo
  --build               Run build gate (default when no action flags)
  --package             Build Debian package into dist/ (runs build gate by default)
  --dist-dir <path>     Output directory for package artifacts (default: ./dist)
  --version <version>   Override package version (default: read from Cargo.toml)
  --install             Install binary and systemd unit (no enable/start)
  --enable              Enable and start awg2-harness.service
  --yes                 Confirm system mutations (apt/rustup)
  --skip-fmt            Skip cargo fmt --check
  --help                Show this help
Notes:
  --install is not the production deployment path; it is for manual source-tree installs (staging/debug).
  Use generated .deb packages on production hosts: apt install ./awg2-harness_<version>_amd64.deb
EOF
}

while [[ $# -gt 0 ]]; do
  case "$1" in
    --prepare-build-env) PREPARE_BUILD_ENV=true; HAS_ACTION=true ;;
    --prepare-runtime-env) PREPARE_RUNTIME_ENV=true; HAS_ACTION=true ;;
    --bootstrap-rust) BOOTSTRAP_RUST=true; HAS_ACTION=true ;;
    --build) DO_BUILD=true; HAS_ACTION=true ;;
    --package) PACKAGE=true; HAS_ACTION=true ;;
    --dist-dir)
      [[ $# -ge 2 ]] || { echo "--dist-dir requires value"; exit 1; }
      DIST_DIR="$2"
      shift
      ;;
    --version)
      [[ $# -ge 2 ]] || { echo "--version requires value"; exit 1; }
      PACKAGE_VERSION="$2"
      shift
      ;;
    --install) INSTALL=true; HAS_ACTION=true ;;
    --enable) ENABLE=true; HAS_ACTION=true ;;
    --yes) YES=true ;;
    --skip-fmt) SKIP_FMT=true ;;
    --help|-h) usage; exit 0 ;;
    *) echo "Unknown arg: $1"; usage; exit 1 ;;
  esac
  shift
done

if [[ "$HAS_ACTION" == false ]]; then
  DO_BUILD=true
fi

require_cmd() {
  command -v "$1" >/dev/null 2>&1 || {
    echo "Missing command: $1"
    exit 1
  }
}

setup_root_runner() {
  if [[ "$(id -u)" -eq 0 ]]; then
    RUN_AS_ROOT=()
  else
    require_cmd sudo
    RUN_AS_ROOT=(sudo)
  fi
}

ensure_supported_host() {
  if [[ -f /etc/os-release ]]; then
    # shellcheck disable=SC1091
    source /etc/os-release
    case "${ID:-}" in
      debian|ubuntu) ;;
      *) echo "Unsupported OS: ${ID:-unknown}. Only Debian/Ubuntu are supported."; exit 1 ;;
    esac
  fi

  local arch
  arch="$(uname -m)"
  if [[ "$arch" != "x86_64" && "$arch" != "amd64" ]]; then
    echo "Unsupported arch: $arch. Only amd64/x86_64 is supported."
    exit 1
  fi
}

apt_install_missing() {
  local packages=("$@")
  local missing=()

  require_cmd dpkg-query
  require_cmd apt-get

  for pkg in "${packages[@]}"; do
    if ! dpkg-query -W -f='${Status}' "$pkg" 2>/dev/null | grep -q "install ok installed"; then
      missing+=("$pkg")
    fi
  done

  if [[ "${#missing[@]}" -eq 0 ]]; then
    echo "All required packages already installed"
    return 0
  fi

  echo "Missing packages: ${missing[*]}"
  if [[ "$YES" != true ]]; then
    echo "Re-run with --yes to install them"
    exit 1
  fi

  setup_root_runner
  "${RUN_AS_ROOT[@]}" apt-get update
  "${RUN_AS_ROOT[@]}" apt-get install -y --no-install-recommends "${missing[@]}"
}

bootstrap_rust() {
  require_cmd curl

  if [[ "$YES" != true ]]; then
    echo "This will install rustup and Rust toolchain $RUST_TOOLCHAIN_VERSION"
    echo "Re-run with --yes to proceed"
    exit 1
  fi

  if ! command -v rustup >/dev/null 2>&1; then
    local rustup_script
    rustup_script="$(mktemp)"
    curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs -o "$rustup_script"
    sh "$rustup_script" -y --profile minimal --default-toolchain "$RUST_TOOLCHAIN_VERSION"
    rm -f "$rustup_script"
  fi

  export PATH="$HOME/.cargo/bin:$PATH"
  require_cmd rustup
  rustup toolchain install "$RUST_TOOLCHAIN_VERSION" --profile minimal --component rustfmt --component clippy
  rustup component add rustfmt clippy --toolchain "$RUST_TOOLCHAIN_VERSION"
  rustc --version
}

prepare_build_gate() {
  require_cmd cargo
  require_cmd rustc
  require_cmd gcc
  require_cmd pkg-config
  require_cmd file
  require_cmd ldd

  if [[ ! -f "$RUST_TOOLCHAIN_FILE" ]]; then
    echo "Missing rust toolchain pin file: $RUST_TOOLCHAIN_FILE"
    exit 1
  fi

  if [[ ! -f "$ROOT_DIR/Cargo.lock" ]]; then
    echo "Missing lockfile: $ROOT_DIR/Cargo.lock"
    exit 1
  fi

  if [[ "$SKIP_FMT" != true ]]; then
    cargo fmt --manifest-path "$WORKSPACE_MANIFEST" --all --check
  fi

  if [[ ! -f "$WORKSPACE_MANIFEST" ]]; then
    echo "Missing workspace manifest: $WORKSPACE_MANIFEST"
    exit 1
  fi

  cargo clippy --locked --workspace --all-targets --manifest-path "$WORKSPACE_MANIFEST" -- -D warnings
  cargo test --locked --workspace --release --manifest-path "$WORKSPACE_MANIFEST"
  cargo build --locked --workspace --release --manifest-path "$WORKSPACE_MANIFEST"
  cargo metadata --locked --format-version 1 --manifest-path "$WORKSPACE_MANIFEST" >/dev/null

  if command -v systemd-analyze >/dev/null 2>&1; then
    local docker_unit_present=false
    if [[ -e /lib/systemd/system/docker.service || -e /usr/lib/systemd/system/docker.service || -e /etc/systemd/system/docker.service ]]; then
      docker_unit_present=true
    fi

    if [[ -x /usr/sbin/awg2-harness && -x /usr/sbin/awg2-reboot-scheduler && "$docker_unit_present" == true ]]; then
      systemd-analyze verify "$ROOT_DIR/awg2-harness.service"
      systemd-analyze verify "$ROOT_DIR/awg2-reboot-scheduler.service"
    else
      echo "Skipping source-tree systemd-analyze verify: package runtime files or docker.service are not present on this build host"
    fi
  fi

  file "$TARGET_BIN"
  file "$REBOOT_BIN"
  ldd "$TARGET_BIN" || true
  ldd "$REBOOT_BIN" || true
  "$TARGET_BIN" --help >/dev/null
  "$REBOOT_BIN" --help >/dev/null
  sha256sum "$TARGET_BIN"
  sha256sum "$REBOOT_BIN"
  ls -lh "$TARGET_BIN"
  ls -lh "$REBOOT_BIN"
}

install_artifacts() {
  require_cmd install
  require_cmd systemctl

  if [[ ! -f "$TARGET_BIN" || ! -f "$REBOOT_BIN" ]]; then
    echo "Binary not found: $TARGET_BIN or $REBOOT_BIN"
    echo "Run build first: ./tools/build.sh"
    exit 1
  fi

  if [[ ! -f /etc/awg2-harness/config.toml ]]; then
    echo "Missing /etc/awg2-harness/config.toml"
    echo "Refusing to install example config as production config"
    echo "Create config manually from $ROOT_DIR/config.example.toml and re-run with --install"
    exit 1
  fi

  setup_root_runner
  "${RUN_AS_ROOT[@]}" install -d -m 0755 /usr/sbin
  "${RUN_AS_ROOT[@]}" install -m 0755 "$TARGET_BIN" /usr/sbin/awg2-harness
  "${RUN_AS_ROOT[@]}" install -m 0755 "$REBOOT_BIN" /usr/sbin/awg2-reboot-scheduler
  "${RUN_AS_ROOT[@]}" install -d -m 0755 /lib/systemd/system
  "${RUN_AS_ROOT[@]}" install -m 0644 "$ROOT_DIR/awg2-harness.service" /lib/systemd/system/awg2-harness.service
  "${RUN_AS_ROOT[@]}" install -m 0644 "$ROOT_DIR/awg2-reboot-scheduler.service" /lib/systemd/system/awg2-reboot-scheduler.service

  if command -v systemd-analyze >/dev/null 2>&1; then
    "${RUN_AS_ROOT[@]}" systemd-analyze verify /lib/systemd/system/awg2-harness.service
    "${RUN_AS_ROOT[@]}" systemd-analyze verify /lib/systemd/system/awg2-reboot-scheduler.service
  fi
  "${RUN_AS_ROOT[@]}" systemctl daemon-reload
}

read_package_version_from_manifest() {
  awk -F '"' '/^version\s*=\s*"/ { print $2; exit }' "$CRATE_MANIFEST"
}

package_deb() {
  require_cmd dpkg-deb
  require_cmd install
  require_cmd sha256sum
  require_cmd file
  require_cmd ldd
  require_cmd mktemp

  if [[ "$DO_BUILD" != true ]]; then
    prepare_build_gate
  fi

  if [[ ! -f "$TARGET_BIN" || ! -f "$REBOOT_BIN" ]]; then
    echo "Binary not found after build: $TARGET_BIN or $REBOOT_BIN"
    exit 1
  fi

  local version
  if [[ -n "$PACKAGE_VERSION" ]]; then
    version="$PACKAGE_VERSION"
  else
    version="$(read_package_version_from_manifest)"
  fi

  if [[ -z "$version" ]]; then
    echo "Unable to determine package version"
    exit 1
  fi

  local staging
  staging="$(mktemp -d)"
  trap 'rm -rf "$staging"' RETURN

  install -d -m 0755 "$staging/DEBIAN"
  install -d -m 0755 "$staging/usr/sbin"
  install -d -m 0755 "$staging/lib/systemd/system"
  install -d -m 0755 "$staging/etc/awg2-harness"
  install -d -m 0755 "$staging/usr/share/doc/awg2-harness/repo"
  install -d -m 0755 "$staging/usr/share/doc/awg2-harness/repo/docs"
  install -d -m 0755 "$staging/usr/share/doc/awg2-harness/repo/tools"

  install -m 0755 "$TARGET_BIN" "$staging/usr/sbin/awg2-harness"
  install -m 0755 "$REBOOT_BIN" "$staging/usr/sbin/awg2-reboot-scheduler"
  install -m 0644 "$ROOT_DIR/awg2-harness.service" "$staging/lib/systemd/system/awg2-harness.service"
  install -m 0644 "$ROOT_DIR/awg2-reboot-scheduler.service" "$staging/lib/systemd/system/awg2-reboot-scheduler.service"
  install -m 0644 "$ROOT_DIR/config.example.toml" "$staging/usr/share/doc/awg2-harness/repo/config.example.toml"
  install -m 0644 "$ROOT_DIR/README.md" "$staging/usr/share/doc/awg2-harness/repo/README.md"
  install -m 0644 "$ROOT_DIR/docs/INSTALLATION.md" "$staging/usr/share/doc/awg2-harness/repo/docs/INSTALLATION.md"
  install -m 0644 "$ROOT_DIR/docs/CONFIGURATION.md" "$staging/usr/share/doc/awg2-harness/repo/docs/CONFIGURATION.md"
  install -m 0644 "$ROOT_DIR/docs/ACCEPTANCE_CHECKLIST.md" "$staging/usr/share/doc/awg2-harness/repo/docs/ACCEPTANCE_CHECKLIST.md"
  install -m 0644 "$ROOT_DIR/tools/README.md" "$staging/usr/share/doc/awg2-harness/repo/tools/README.md"

  cat >"$staging/DEBIAN/control" <<EOF
Package: awg2-harness
Version: $version
Section: net
Priority: optional
Architecture: amd64
Maintainer: AWG2 Harness
Depends: libc6, iproute2, wireguard-tools, nftables, kmod, util-linux, procps, systemd
Description: Host-side orchestrator for AmneziaWG traffic shaping and lifecycle recovery
 AWG2 Harness manages AmneziaWG traffic shaping, IFB ingress shaping,
 nftables anti-torrent guard, reboot scheduling, swap setup and daemonized
 drift recovery on dedicated Debian hosts. Includes external reboot scheduler.
EOF

  cat >"$staging/DEBIAN/postinst" <<'EOF'
#!/bin/sh
set -e

if command -v systemctl >/dev/null 2>&1; then
  systemctl daemon-reload || true
fi

exit 0
EOF

  cat >"$staging/DEBIAN/postrm" <<'EOF'
#!/bin/sh
set -e

if command -v systemctl >/dev/null 2>&1; then
  systemctl daemon-reload || true
fi

exit 0
EOF

  chmod 0755 "$staging/DEBIAN/postinst" "$staging/DEBIAN/postrm"

  mkdir -p "$DIST_DIR"
  local pkg_name
  pkg_name="awg2-harness_${version}_amd64.deb"
  local pkg_path
  pkg_path="$DIST_DIR/$pkg_name"

  dpkg-deb --build "$staging" "$pkg_path"
  dpkg-deb --info "$pkg_path"
  dpkg-deb --contents "$pkg_path" | sort

  (
    cd "$DIST_DIR"
    sha256sum "$pkg_name" > SHA256SUMS
  )

  echo "Package created: $pkg_path"
  echo "Checksums: $DIST_DIR/SHA256SUMS"
}

enable_service() {
  require_cmd systemctl
  setup_root_runner
  "${RUN_AS_ROOT[@]}" systemctl enable --now awg2-harness.service
  "${RUN_AS_ROOT[@]}" systemctl enable --now awg2-reboot-scheduler.service
}

ensure_supported_host

if [[ "$PREPARE_BUILD_ENV" == true ]]; then
  apt_install_missing "${BUILD_PACKAGES[@]}"
fi

if [[ "$PREPARE_RUNTIME_ENV" == true ]]; then
  apt_install_missing "${RUNTIME_PACKAGES[@]}"
fi

if [[ "$BOOTSTRAP_RUST" == true ]]; then
  bootstrap_rust
fi

if [[ "$DO_BUILD" == true ]]; then
  prepare_build_gate
fi

if [[ "$PACKAGE" == true ]]; then
  package_deb
fi

if [[ "$INSTALL" == true ]]; then
  install_artifacts
fi

if [[ "$ENABLE" == true ]]; then
  enable_service
fi

if [[ "$DO_BUILD" == true ]]; then
  echo "Build completed: $TARGET_BIN"
fi