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

ROOT=$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")/.." && pwd)
PREFIX=${PREFIX:-"$HOME/.local"}
BUILD_DIR=${BUILD_DIR:-"$ROOT/build"}
INSTALL_DEPS=0
ACTIVATE=0
ASSUME_YES=0
MINIMUM_RUST=1.87.0

usage() {
    cat <<'EOF'
Usage: scripts/install.sh [options]

Options:
  --deps          Offer to install missing build dependencies
  --no-deps       Do not install dependencies (default)
  --activate      Activate Lumen in the running Plasma session
  --no-activate   Build and install only (default)
  --yes, -y       Assume yes for dependency installation prompts
  --help          Show this help

Environment:
  PREFIX          Installation prefix (default: ~/.local)
  BUILD_DIR       Build directory (default: ./build)
  LUMEN_STATE_DIR Activation backups and logs (default: PREFIX/share/lumen-wallpaper)
EOF
}

log() {
    printf 'Lumen installer: %s\n' "$*"
}

fail() {
    printf 'Lumen installer: %s\n' "$*" >&2
    exit 1
}

while (($#)); do
    case "$1" in
        --deps) INSTALL_DEPS=1 ;;
        --no-deps) INSTALL_DEPS=0 ;;
        --activate) ACTIVATE=1 ;;
        --no-activate) ACTIVATE=0 ;;
        --yes|-y) ASSUME_YES=1 ;;
        --help)
            usage
            exit 0
            ;;
        *) fail "Unknown option: $1" ;;
    esac
    shift
done

confirm() {
    local prompt=$1
    local answer
    if ((ASSUME_YES)); then
        return 0
    fi
    if [[ ! -t 0 ]]; then
        return 1
    fi
    read -r -p "$prompt [y/N] " answer
    [[ $answer == y || $answer == Y || $answer == yes || $answer == YES ]]
}

rust_version_ok() {
    command -v rustc >/dev/null 2>&1 || return 1
    local version
    version=$(rustc --version 2>/dev/null | awk '{print $2}')
    [[ -n $version ]] || return 1
    printf '%s\n%s\n' "$MINIMUM_RUST" "$version" | sort -V -C
}

ecm_available() {
    local probe_dir
    probe_dir=$(mktemp -d "${TMPDIR:-/tmp}/lumen-ecm-probe.XXXXXX")
    if (cd "$probe_dir" && cmake --find-package \
        -DNAME=ECM -DCOMPILER_ID=GNU -DLANGUAGE=CXX -DMODE=EXIST \
        >/dev/null 2>&1); then
        rm -rf -- "$probe_dir"
        return 0
    fi
    rm -rf -- "$probe_dir"
    return 1
}

dependencies_ready() {
    local command_name
    for command_name in cmake ninja c++ cargo rustc pkg-config; do
        command -v "$command_name" >/dev/null 2>&1 || return 1
    done
    rust_version_ok || return 1
    pkg-config --exists Qt6Core Qt6Gui Qt6Qml Qt6Quick || return 1
    ecm_available || return 1
}

run_as_root() {
    if ((EUID == 0)); then
        "$@"
    else
        command -v sudo >/dev/null 2>&1 || fail "sudo is required for system packages"
        sudo "$@"
    fi
}

install_dependencies() {
    if dependencies_ready; then
        log "Build dependencies are already available"
        return
    fi
    ((INSTALL_DEPS)) || return
    confirm "Install missing build dependencies with the system package manager?" \
        || fail "Build dependencies are required; install them manually or rerun with --deps"

    if command -v dnf >/dev/null 2>&1; then
        run_as_root dnf install -y \
            gcc-c++ cargo rustc cmake ninja-build extra-cmake-modules pkgconf-pkg-config curl \
            qt6-qtbase-devel qt6-qtdeclarative-devel vulkan-loader-devel vulkan-headers \
            kf6-kirigami plasma-workspace
    elif command -v apt-get >/dev/null 2>&1; then
        run_as_root apt-get update
        run_as_root apt-get install -y \
            build-essential cargo rustc cmake ninja-build extra-cmake-modules pkg-config curl \
            qt6-base-dev qt6-declarative-dev libvulkan-dev \
            qml6-module-org-kde-kirigami plasma-workspace
    elif command -v pacman >/dev/null 2>&1; then
        run_as_root pacman -Sy --needed --noconfirm \
            base-devel cargo cmake ninja extra-cmake-modules pkgconf curl \
            qt6-base qt6-declarative vulkan-headers kirigami plasma-workspace
    else
        fail "Unsupported package manager. Install CMake, Ninja, a C++ compiler, Rust, Qt6, ECM, Vulkan, Kirigami, and Plasma Workspace manually"
    fi
}

ensure_rust() {
    if rust_version_ok; then
        return
    fi
    ((INSTALL_DEPS)) || return
    confirm "Rust $MINIMUM_RUST or newer is required. Install/update it with rustup in your home directory?" \
        || fail "Rust $MINIMUM_RUST or newer is required"

    if command -v rustup >/dev/null 2>&1; then
        rustup toolchain install stable --profile minimal
    else
        command -v curl >/dev/null 2>&1 || fail "curl is required to download rustup"
        local rustup_script
        rustup_script=$(mktemp "${TMPDIR:-/tmp}/lumen-rustup.XXXXXX")
        curl --proto '=https' --tlsv1.2 -fsSL https://sh.rustup.rs -o "$rustup_script"
        sh "$rustup_script" -y --profile minimal --no-modify-path
        rm -f -- "$rustup_script"
    fi
    export PATH="$HOME/.cargo/bin:$PATH"
    export RUSTUP_TOOLCHAIN=stable
    rust_version_ok || fail "The Rust toolchain is still older than $MINIMUM_RUST"
}

preflight() {
    local command_name
    for command_name in cmake ninja c++ cargo rustc pkg-config; do
        command -v "$command_name" >/dev/null 2>&1 \
            || fail "Missing required command: $command_name"
    done
    rust_version_ok || fail "Rust $MINIMUM_RUST or newer is required"
    pkg-config --exists Qt6Core Qt6Gui Qt6Qml Qt6Quick \
        || fail "Qt6 development packages are required"
    ecm_available || fail "Extra CMake Modules (ECM) are required"
}

install_dependencies
ensure_rust
preflight

cmake -S "$ROOT" -B "$BUILD_DIR" -G Ninja \
    -DCMAKE_BUILD_TYPE=Release \
    -DCMAKE_INSTALL_PREFIX="$PREFIX"
cmake --build "$BUILD_DIR"
cmake --install "$BUILD_DIR"

log "Installed Lumen Wallpaper to $PREFIX"
if ((ACTIVATE)); then
    BUILD_DIR=${LUMEN_STATE_DIR:-"$PREFIX/share/lumen-wallpaper"} \
        "$ROOT/scripts/activate.sh"
else
    log "Activate it with scripts/activate.sh or choose Lumen Wallpaper in KDE settings"
fi