#!/bin/bash
#Script to build ghostty from source. It automatically grabs required zig version binary.
#v1.0.4

set -euo pipefail

# === Config ===
PREFIX="${HOME}/.local"
OPTIMIZATION="ReleaseFast"
GHOSTTY_REPO="https://github.com/ghostty-org/ghostty.git"
GHOSTTY_PUBKEY="RWQlAjJC23149WL2sEpT/l0QKy7hMIFhYdQOFy0Z7z7PbneUgvlsnYcV"
BUILD_DIR="/tmp/ghostty_build"
CLEAN_BUILD=false

# === Parse arguments ===
for arg in "$@"; do
  case $arg in
    --clean)
      CLEAN_BUILD=true
      shift
      ;;
  esac
done

# === Helpers ===
command_exists() { command -v "$1" >/dev/null 2>&1; }
info() { echo "==> $*"; }
error() { echo "ERROR: $*" >&2; exit 1; }

# === Create build directory ===
mkdir -p "$BUILD_DIR"
cd "$BUILD_DIR"

# === Version selection ===
choose_version() {
  info "Fetching available Ghostty versions from GitHub..."
  local tags
  tags=$(curl -s https://api.github.com/repos/ghostty-org/ghostty/tags \
    | grep '"name":' \
    | cut -d'"' -f4)

  if [ -z "$tags" ]; then
    error "Could not fetch tags from GitHub."
  fi

  local latest
  latest=$(echo "$tags" | head -n1)

  echo
  echo "Available Ghostty versions:"
  echo " 0) $latest   (latest release)"
  echo " 1) tip       (development)"
  local i=2
  local arr=()
  while read -r tag; do
    if [ "$tag" != "$latest" ] && [ "$tag" != "tip" ]; then
      echo " $i) $tag"
      arr+=("$tag")
      i=$((i+1))
    fi
  done <<< "$tags"

  echo
  read -rp "Select a version [0-$((i-1))]: " choice

  case "$choice" in
    0) GHOSTTY_VERSION="$latest" ;;
    1) GHOSTTY_VERSION="tip" ;;
    *) local idx=$((choice-2)); GHOSTTY_VERSION="${arr[$idx]}" ;;
  esac

  info "Selected Ghostty version: $GHOSTTY_VERSION"
}

# === Zig version mapping ===
resolve_zig_version() {
  case "$GHOSTTY_VERSION" in
    1.0.*|1.1.*) echo "0.13.0" ;;
    1.2.*) echo "0.14.1" ;;
    tip) echo "0.14.1" ;;
    v*)  
      local ver="${GHOSTTY_VERSION#v}"
      case "$ver" in
        1.0.*|1.1.*) echo "0.13.0" ;;
        1.2.*) echo "0.14.1" ;;
        *) error "Unknown mapping for Ghostty version $ver";;
      esac
      ;;
    *) error "Unknown Ghostty version format: $GHOSTTY_VERSION";;
  esac
}

# === Download Zig standalone binary ===
setup_zig() {
  local zig_version="$1"
  local os=$(uname -s | tr '[:upper:]' '[:lower:]')
  local arch=$(uname -m)

  case "$os" in
    linux) os="linux" ;;
    darwin) os="macos" ;;
    *) error "Unsupported OS: $os";;
  esac

  case "$arch" in
    x86_64) arch="x86_64" ;;
    aarch64|arm64) arch="aarch64" ;;
    *) error "Unsupported arch: $arch";;
  esac

  local tarball
  local dirname

  if [[ "$zig_version" < "0.14.1" ]]; then
    tarball="zig-${os}-${arch}-${zig_version}.tar.xz"
    dirname="zig-${os}-${arch}-${zig_version}"
  else
    tarball="zig-${arch}-${os}-${zig_version}.tar.xz"
    dirname="zig-${arch}-${os}-${zig_version}"
  fi

  if [ ! -d "$dirname" ]; then
    info "Downloading Zig $zig_version from https://ziglang.org/download/$zig_version/$tarball"
    curl -fLO "https://ziglang.org/download/$zig_version/$tarball"
    tar -xf "$tarball"
  fi

  export PATH="$BUILD_DIR/$dirname:$PATH"
  info "Using Zig at $(command -v zig) ($(zig version))"
}

# === Install build dependencies ===
install_deps_linux() {
  if ! command_exists apt-get && ! command_exists pacman && ! command_exists dnf; then
    error "No supported package manager found (apt, pacman, dnf). Install dependencies manually."
  fi

  local distro=""
  if [ -f /etc/os-release ]; then
    . /etc/os-release
    distro="$ID"
  fi

  if command_exists apt-get; then
    info "Installing dependencies via apt-get..."
    sudo apt-get update

    # Base packages
    sudo apt-get install -y git libgtk-4-dev gettext libxml2-utils pkg-config curl tar xz-utils g++

    # Harfbuzz development
    sudo apt-get install -y libharfbuzz-dev libharfbuzz-gobject0

    # GTK Blueprint compiler
    sudo apt-get install -y blueprint-compiler

    # libadwaita package
    case "$distro" in
      ubuntu|debian)
        if ! sudo apt-get install -y libadwaita-1-dev; then
          sudo apt-get install -y libadwaita-dev || true
        fi
        ;;
      *)
        sudo apt-get install -y libadwaita-1-dev libadwaita-dev || true
        ;;
    esac

    # GTK layer-shell package
    case "$distro" in
      ubuntu)
        sudo apt-get install -y libgtk-layer-shell-dev || true
        ;;
      debian)
        sudo apt-get install -y libgtk4-layer-shell-dev || true
        ;;
      *)
        sudo apt-get install -y libgtk4-layer-shell-dev libgtk-layer-shell-dev || true
        ;;
    esac

    # Verify critical pkg-config dependencies
    for pkg in gtk4 libadwaita-1 gtk-layer-shell-1.0; do
      if ! pkg-config --exists "$pkg"; then
        error "Missing required development package: $pkg. Did apt-get install succeed?"
      fi
    done

  elif command_exists pacman; then
    sudo pacman -Sy --noconfirm \
      git gtk4 gtk4-layer-shell libadwaita gettext pkgconf curl tar xz g++ blueprint-compiler harfbuzz
  elif command_exists dnf; then
    sudo dnf install -y \
      git gtk4-devel gtk4-layer-shell-devel libadwaita-devel \
      gettext pkgconf curl tar xz g++ blueprint-compiler harfbuzz-devel
  fi
}

# === Clone Ghostty repo and checkout version ===
fetch_source_git() {
  if [ ! -d "ghostty" ]; then
    git clone "$GHOSTTY_REPO"
  fi
  cd ghostty
  git fetch --tags --quiet

  if [ "$GHOSTTY_VERSION" = "tip" ]; then
    git checkout main
  else
    git checkout "$GHOSTTY_VERSION"
  fi
}

# === Build and install Ghostty ===
build_install() {
  zig build -Doptimize="$OPTIMIZATION"
  zig build install -p "$PREFIX" -Doptimize="$OPTIMIZATION"
  info "Ghostty installed to $PREFIX/bin/ghostty"
}

# === Clean build directory ===
cleanup_build() {
  if $CLEAN_BUILD; then
    info "Cleaning up build directory $BUILD_DIR"
    cd ..
    rm -rf "$BUILD_DIR"
  fi
}

# === Main ===
main() {
  choose_version
  if [[ "$(uname -s)" == "Linux" ]]; then
    install_deps_linux
  fi
  local zig_ver
  zig_ver=$(resolve_zig_version)
  setup_zig "$zig_ver"
  fetch_source_git
  build_install
  cleanup_build
}

main "$@"