#!/bin/bash
#
# setup.sh — unified Fedora configuration
# Target: bare/minimal Fedora 44 and newer
#
set -uo pipefail

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
# shellcheck source=lib/common.sh
source "$SCRIPT_DIR/lib/common.sh"
# shellcheck source=lib/session.sh
source "$SCRIPT_DIR/lib/session.sh"

#------------------------------------------
# Defaults + argument parsing
#   DEBUG_MODE must be initialised before anything reads it under set -u.
#------------------------------------------
DEBUG_MODE=false
ASSUME_YES=false
DE=""
TWM=""
SELINUX_OPT=""
SNAPPER_OPT=""

usage() {
    cat <<'EOF'
setup.sh — unified Fedora configuration (Fedora 44+)

Usage:
  ./setup.sh                              interactive: pick a DE and a TWM
  ./setup.sh --de=none --twm=niri         non-interactive, explicit choices
  ./setup.sh --debug                      pause after each section

Options:
  --de=NAME     gnome | plasma | xfce | none
  --twm=NAME    chadwm | hyprland | mango | niri | none
  --selinux=X   keep | disabled   (asked, default keep)
  --snapper=X   yes | no          (asked when / is btrfs, default yes)
  -y, --yes     never prompt (requires --de and --twm)
  -d, --debug   pause after each section instead of aborting on error
  -h, --help    show this help

Valid DE/TWM combinations:
  any DE + any TWM   DE provides the session, TWM is added alongside it
  none    + any TWM  TWM-only machine, SDDM is installed as the greeter
  any DE  + none     plain desktop, no tiling window manager
  none    + none     refused: that is not a graphical system

Notes:
  * chadwm is an X11 window manager; the other three are Wayland compositors.
  * Run as your normal user, not root. sudo is used where needed.
EOF
}

for arg in "$@"; do
    case "$arg" in
        -d|--debug) DEBUG_MODE=true ;;
        -y|--yes)   ASSUME_YES=true ;;
        --de=*)     DE="${arg#*=}" ;;
        --selinux=*) SELINUX_OPT="${arg#*=}" ;;
        --snapper=*) SNAPPER_OPT="${arg#*=}" ;;
        --twm=*)    TWM="${arg#*=}" ;;
        -h|--help)  usage; exit 0 ;;
        *)
            err "Unknown argument: $arg"
            printf "\n"
            usage
            exit 2
            ;;
    esac
done
export DEBUG_MODE ASSUME_YES

if is_debug; then
    set +e   # walk through failures instead of dying on the first one
else
    set -e
fi

#------------------------------------------
# Preconditions
#------------------------------------------
# clear can fail without TERM (cron, piped install, ssh without a tty) and would
# abort the whole run under set -e.
clear 2>/dev/null || true

printf "\n"
color_yellow "----------------------------------------------------------------"
color_yellow "Fedora unified configuration"
color_yellow "----------------------------------------------------------------"

if [[ ${EUID} -eq 0 ]]; then
    err "Do not run this as root. Run it as your user; it calls sudo itself."
    exit 1
fi

if [[ "$ASSUME_YES" == "true" && ( -z "$DE" || -z "$TWM" ) ]]; then
    err "--yes requires explicit --de and --twm, so nothing is guessed on an"
    err "unattended run. Example:"
    err "    ./setup.sh --yes --de=none --twm=niri"
    exit 2
fi

if is_debug; then
    color_red "!!! DEBUG MODE ENABLED !!!"
    color_red "The script will pause after each section."
fi

#------------------------------------------
# OS gate — Fedora only, 44+
#------------------------------------------
step "OS detection"
rule

# Overridable so the script can be tested on a non-Fedora host.
OS_RELEASE_FILE="${OS_RELEASE_FILE:-/etc/os-release}"
# shellcheck source=/dev/null
source "$OS_RELEASE_FILE"

OS_ID="${ID:-unknown}"; OS_ID="${OS_ID,,}"
OS_PRETTY="${PRETTY_NAME:-unknown}"

if [[ "$OS_ID" != "fedora" ]]; then
    err "Unsupported distribution: $OS_PRETTY (ID=${OS_ID})"
    err "This repo targets Fedora only. RHEL clones are refused on purpose:"
    err "they ship no dnf5 config-manager and no RPM Fusion, so both the base"
    err "setup and every module would fail half-way."
    exit 1
fi

FEDORA_REL=$(rpm -E %fedora)
if [[ "$FEDORA_REL" =~ ^[0-9]+$ ]] && (( FEDORA_REL < 44 )); then
    err "$OS_PRETTY reports release ${FEDORA_REL}, but this setup targets Fedora 44+."
    exit 1
fi

ok "Detected: $OS_PRETTY (release ${FEDORA_REL})"
pause_if_debug

#------------------------------------------
# 1 Base settings
#------------------------------------------
step "1 Base settings"
rule

if ! command -v curl >/dev/null 2>&1; then
    info "curl missing. Installing..."
    install_packages curl
fi

# config-manager lives in dnf5-plugins; every repo step below depends on it.
if ! dnf config-manager --help >/dev/null 2>&1; then
    info "dnf config-manager missing. Installing dnf5-plugins..."
    install_packages dnf5-plugins
fi

info "Tuning DNF..."
sudo dnf config-manager setopt max_parallel_downloads=20
sudo dnf config-manager setopt defaultyes=True

info "Refreshing metadata..."
sudo dnf makecache --refresh

add_rpmfusion_repo
# Terra up front: it carries mangowc (noctalia moved into Fedora proper in
# F44). Idempotent; also kept for the standalone-mango-module case.
add_terra_repo
pause_if_debug

if ! command -v flatpak >/dev/null 2>&1; then
    info "Flatpak missing. Installing..."
    install_packages flatpak
fi
info "Ensuring Flathub is available (system-wide)..."
sudo flatpak remote-add --if-not-exists --system flathub https://dl.flathub.org/repo/flathub.flatpakrepo

info "Updating the system..."
sudo dnf update -y
pause_if_debug

#------------------------------------------
# 2 Menu helpers
#------------------------------------------
# $1 = prompt, $2 = default answer, rest = valid answers
ask_choice() {
    local prompt="$1" default="$2"; shift 2
    local answer
    if [[ "$ASSUME_YES" == "true" ]]; then
        echo "$default"
        return 0
    fi
    while true; do
        if ! read -t 60 -rp "$prompt (default: $default): " answer; then
            printf "\n"
            answer=""
        fi
        answer="${answer:-$default}"
        answer="${answer,,}"
        local v
        for v in "$@"; do
            if [[ "$answer" == "$v" ]]; then
                echo "$answer"
                return 0
            fi
        done
        err "Invalid option: '$answer'. Choose from: $*"
    done
}

# Ask a yes/no question; $2 is the default (yes|no). Honours --yes.
ask_yes_no() {
    local prompt="$1" default="$2" answer
    if [[ "$ASSUME_YES" == "true" ]]; then
        echo "$default"
        return 0
    fi
    while true; do
        read -t 60 -rp "$prompt [y/n] (default: $default): " answer || printf "\n"
        answer="${answer,,}"
        [[ -z "$answer" ]] && answer="$default"
        case "$answer" in
            y|yes) echo "yes"; return 0 ;;
            n|no)  echo "no";  return 0 ;;
        esac
        err "Please answer y or n."
    done
}

#------------------------------------------
# 3 System settings
#------------------------------------------
SELINUX_DISABLED=false
BTRFS_SNAPPER=false

if [[ -z "$SELINUX_OPT" ]]; then
    step "3 System settings"
    rule
    printf "\n"
    printf "\n"
    choice=$(ask_yes_no "Disable SELinux permanently? (not recommended)" "no")
    [[ "$choice" == "yes" ]] && SELINUX_DISABLED=true
    printf "\n"
    if findmnt -n -o FSTYPE / 2>/dev/null | grep -q btrfs; then
        ok "Root filesystem is btrfs — snapshot support is available."
        choice=$(ask_yes_no "Set up snapper + grub-btrfs snapshots and zstd compression?" "yes")
        [[ "$choice" == "yes" ]] && BTRFS_SNAPPER=true
    else
        info "Root filesystem is not btrfs; skipping snapshot setup."
    fi
fi

case "${SELINUX_OPT:-}" in
    disabled) SELINUX_DISABLED=true ;;
    keep|"")  : ;;
    *) err "Unknown --selinux value: '$SELINUX_OPT' (keep|disabled)"; exit 2 ;;
esac
case "${SNAPPER_OPT:-}" in
    yes)   BTRFS_SNAPPER=true ;;
    no|"") : ;;
    *) err "Unknown --snapper value: '$SNAPPER_OPT' (yes|no)"; exit 2 ;;
esac
pause_if_debug

#------------------------------------------
# 4 Desktop environment selection
#------------------------------------------
if [[ -z "$DE" ]]; then
    step "3 Desktop environment"
    rule
    printf "\n"
    color_gray "  This system is treated as a bare Fedora install — picking a DE"
    color_gray "  here is what gives you a graphical login."
    printf "\n"
    echo "  1) GNOME     (gdm)"
    echo "  2) Plasma    (sddm)"
    echo "  3) XFCE      (sddm)"
    echo "  4) None      (TWM only — SDDM will be installed by the TWM module)"
    printf "\n"
    choice=$(ask_choice "Select desktop environment [1/2/3/4]" "4" 1 2 3 4)
    case "$choice" in
        1) DE="gnome" ;;
        2) DE="plasma" ;;
        3) DE="xfce" ;;
        4) DE="none" ;;
    esac
fi

case "$DE" in
    gnome|plasma|xfce|none) ;;
    *) err "Unknown --de value: '$DE' (gnome|plasma|xfce|none)"; exit 2 ;;
esac
pause_if_debug

#------------------------------------------
# 5 Tiling window manager selection
#------------------------------------------
if [[ -z "$TWM" ]]; then
    step "5 Tiling window manager"
    rule
    printf "\n"
    echo "  1) Niri       (Wayland, scrollable)"
    echo "  2) Hyprland   (Wayland, dynamic)"
    echo "  3) MangoWC    (Wayland, dwl-based, Terra repo)"
    echo "  4) chadwm     (X11, dwm fork, built from source)"
    echo "  5) None"
    printf "\n"
    choice=$(ask_choice "Select tiling window manager [1/2/3/4/5]" "5" 1 2 3 4 5)
    case "$choice" in
        1) TWM="niri" ;;
        2) TWM="hyprland" ;;
        3) TWM="mango" ;;
        4) TWM="chadwm" ;;
        5) TWM="none" ;;
    esac
fi

case "$TWM" in
    niri|hyprland|mango|chadwm|none) ;;
    *) err "Unknown --twm value: '$TWM' (niri|hyprland|mango|chadwm|none)"; exit 2 ;;
esac

ok "Selection: DE=${DE} TWM=${TWM}"

# A bare install with neither is not a graphical system. Refuse rather than
# leave the user with a machine that boots to a black screen.
if [[ "$DE" == "none" && "$TWM" == "none" ]]; then
    err "DE=none with TWM=none would leave no graphical session at all."
    err "Pick a desktop environment, a tiling window manager, or both."
    exit 2
fi
pause_if_debug

#------------------------------------------
# 5 Dispatch
#------------------------------------------
export DE TWM

run_module() {
    local path="$1"
    if [[ ! -f "$path" ]]; then
        err "Module not found: $path"
        return 1
    fi
    info "Running $(basename "$path")"
    printf "\n"
    # Separate process: a module's own shell options and exit codes stay its own.
    bash "$path"
}

step "5 Installation"
rule

if [[ "$SELINUX_DISABLED" == "true" ]]; then
    disable_selinux
    pause_if_debug
fi

if [[ "$BTRFS_SNAPPER" == "true" ]]; then
    ensure_btrfs_compression
    setup_snapper
    pause_if_debug
fi

if [[ "$DE" != "none" ]]; then
    run_module "$SCRIPT_DIR/modules/de/${DE}.sh"
    pause_if_debug
fi

if [[ "$TWM" != "none" ]]; then
    run_module "$SCRIPT_DIR/modules/twm/${TWM}.sh"
    pause_if_debug
fi

#------------------------------------------
# 6 Done
#------------------------------------------
step "7 Summary"
rule
ok "DE:  $DE"
ok "TWM: $TWM"
ok "SELinux: $([[ "$SELINUX_DISABLED" == "true" ]] && echo disabled || echo keeping)"; ok "Btrfs snapshots: $([[ "$BTRFS_SNAPPER" == "true" ]] && echo yes || echo skipped)"
DM=$(detect_display_manager)
ok "Display manager: ${DM:-none}"

if [[ -z "$DM" ]]; then
    warn "No display manager is active. You will boot to a text console."
    warn "Install one, or run a TWM module which sets up SDDM."
fi

printf "\n"
color_green "Fedora setup complete. A reboot is recommended."
if [[ "$ASSUME_YES" == "true" ]]; then
    info "Unattended run: not rebooting."
    exit 0
fi

if read -t 15 -rp "Reboot now? [y/N]: " reboot_choice; then
    case "${reboot_choice,,}" in
        y|yes)
            color_red "Rebooting now."
            sudo reboot
            ;;
        *)
            color_yellow "Skipping reboot."
            exit 0
            ;;
    esac
else
    color_yellow "No input detected. Skipping reboot for safety."
    exit 0
fi