#!/usr/bin/env bash
# install-git-cliff.sh – fetches the latest or specified git-cliff binary
# Usage (back-compatible):
#   sudo ./install-git-cliff.sh                          # latest version, default arch/dir
#   sudo ./install-git-cliff.sh 2.9.1                    # specific version
# Extended options:
#   sudo ./install-git-cliff.sh -a x86_64-linux-musl [<ver>]   # custom arch
#   sudo ./install-git-cliff.sh -d /opt/tools [<ver>]          # custom install dir
#   sudo ./install-git-cliff.sh -n [<ver>]                     # dry-run (no install)
#   sudo ./install-git-cliff.sh -h | --help                    # help
#
# Behaviour:
#   • If git-cliff is already in \$PATH and **no version** was requested, the script exits early.
#   • If a specific version was requested, the installed version is compared; identical → exit, different → upgrade.
set -euo pipefail

REPO="orhun/git-cliff"

# ───────────────────────────────────────────────
# Defaults (internal vs. user-facing)
ARCH_OS_DEFAULT="x86_64-unknown-linux-gnu"
DEFAULT_ARCH_DISPLAY="${ARCH_OS_DEFAULT/-unknown-/}"  # shown to user → x86_64-linux-gnu
INSTALL_DIR_DEFAULT="/usr/local/bin"
ARCH_OS="$ARCH_OS_DEFAULT"
INSTALL_DIR="$INSTALL_DIR_DEFAULT"
VERSION="latest"
DRY_RUN=false
USER_VERSION_SPECIFIED=false
# ───────────────────────────────────────────────

# 0 Help function
show_help() {
  cat <<EOF
install-git-cliff.sh – Installs the git-cliff binary

Usage:
  sudo ./install-git-cliff.sh [options] [<version>]

Options:
  -a, --arch <triplet>   Target architecture (default: ${DEFAULT_ARCH_DISPLAY})
  -d, --dir  <path>      Installation directory (default: ${INSTALL_DIR_DEFAULT})
  -n, --dry-run          Download and verify, but do NOT install
  -h, --help             Show this help message

Arguments:
  <version>              git-cliff version to install (default: latest)

Behaviour:
  • If git-cliff is already in PATH and no version was requested the script exits.
  • If a specific version was requested, the installed version is compared and
    only upgraded if it differs.

Supported architecture triplets (examples):
  aarch64-linux-gnu / musl / apple-darwin / pc-windows-msvc
  i686-linux-gnu / musl / pc-windows-msvc
  x86_64-linux-gnu / musl / apple-darwin / pc-windows-*
EOF
}

# 1 Parse options (keeps old single-arg form)
POSITIONAL=()
while [[ $# -gt 0 ]]; do
  case "$1" in
    -h|--help) show_help; exit 0 ;;
    -n|--dry-run) DRY_RUN=true; shift ;;
    -a|--arch)
      [[ $# -lt 2 ]] && { echo "❌ Option $1 requires an argument"; exit 1; }
      ARCH_OS_INPUT="$2"; shift 2 ;;
    -d|--dir)
      [[ $# -lt 2 ]] && { echo "❌ Option $1 requires an argument"; exit 1; }
      INSTALL_DIR="$2"; shift 2 ;;
    *) POSITIONAL+=("$1"); shift ;;
  esac
done
if [[ ${#POSITIONAL[@]} -gt 0 ]]; then
  VERSION="${POSITIONAL[0]}"
  USER_VERSION_SPECIFIED=true
fi

# 2 Normalize architecture (strip "unknown" for user input → add internally)
if [[ -n "${ARCH_OS_INPUT:-}" ]]; then
  ARCH_OS="$ARCH_OS_INPUT"
  if [[ "$ARCH_OS" =~ -linux- ]] && [[ ! "$ARCH_OS" =~ -unknown-linux- ]]; then
    ARCH_OS="${ARCH_OS/-linux-/-unknown-linux-}"
  fi
fi

# 3 Pre-check existing installation
if command -v git-cliff >/dev/null; then
  INSTALLED_PATH=$(command -v git-cliff)
  INSTALLED_VER=$(git-cliff -V | awk '{print $2}')
  if ! $USER_VERSION_SPECIFIED; then
    echo "✅ git-cliff already present at ${INSTALLED_PATH} (version ${INSTALLED_VER}) – nothing to do."
    exit 0
  else
    # strip leading 'v' for comparison consistency
    REQ_VER="${VERSION#v}"
    if [[ "$INSTALLED_VER" == "$REQ_VER" ]]; then
      echo "✅ git-cliff ${INSTALLED_VER} already installed – requested version matches."
      exit 0
    else
      echo "ℹ️  git-cliff ${INSTALLED_VER} installed, upgrading to ${REQ_VER}..."
    fi
  fi
fi

# 4 Check for required tools
need() { command -v "$1" >/dev/null || { echo "$1 is missing"; exit 1; }; }
need curl; need tar; need grep; need sed; need awk; need jq

# 5 Determine version → Fetch release JSON
if [[ "$VERSION" == "latest" ]]; then
  API_URL="https://api.github.com/repos/${REPO}/releases/latest"
else
  API_URL="https://api.github.com/repos/${REPO}/releases/tags/v${VERSION}"
fi

echo "🔍 Fetching release info ($API_URL)…"
JSON=$(curl -fsSL "$API_URL") || { echo "❌ Failed to fetch release info"; exit 1; }

VERSION=$(jq -r '.tag_name' <<< "$JSON") || { echo "❌ Could not extract version"; exit 1; }

ASSET_URL=$(jq -r '.assets[]?.browser_download_url' <<< "$JSON" |
  grep -E "${ARCH_OS}\.(tar\.(gz|xz)|zip)$" | head -n1)

[[ -z "$ASSET_URL" ]] && { echo "❌ Matching asset not found for architecture ${ARCH_OS}"; exit 1; }

ASSET_FILE=$(basename "$ASSET_URL")
echo "📦 Downloading git-cliff ${VERSION} (${ASSET_FILE}) …"
TMP=$(mktemp -d)
curl -#L -o "${TMP}/${ASSET_FILE}" "$ASSET_URL"

# 6 Extract based on file extension
case "$ASSET_FILE" in
  *.tar.gz|*.tgz) tar -C "$TMP" -xzf "${TMP}/${ASSET_FILE}" ;;
  *.tar.xz)       tar -C "$TMP" -xJf "${TMP}/${ASSET_FILE}" ;;
  *.zip)          need unzip; unzip -q "${TMP}/${ASSET_FILE}" -d "$TMP" ;;
  *) echo "❌ Unknown archive format: $ASSET_FILE"; exit 1 ;;
esac

# 7 Locate & (maybe) install binary
BIN_PATH=$(find "$TMP" -type f -name git-cliff -perm -u+x | head -n1)
[[ -z "$BIN_PATH" ]] && { echo "❌ Binary not found"; exit 1; }

if $DRY_RUN; then
  echo "🧪 Dry-run: verified git-cliff binary at ${BIN_PATH}"
  echo "ℹ️  Would install to: ${INSTALL_DIR}/git-cliff (sudo install -m755 …)"
  echo "✅ git-cliff $("$BIN_PATH" --version) would be installed successfully"
else
  sudo install -m755 "$BIN_PATH" "${INSTALL_DIR}/git-cliff"
  echo "✅ git-cliff $(git-cliff --version) installed in ${INSTALL_DIR}"
fi