#!/bin/bash
# greetd-regreet.sh — greetd + ReGreet (cyberqueer-themed, Wayland-native greeter)
#
# The Wayland-native alternative to the lightdm module. lightdm-gtk-greeter is an
# Xorg client, which on this multi-monitor / HiDPI / Wayland box means: a monitor
# can come up blank, the greeter renders tiny, and the Xorg→Wayland VT handover
# can race so the Hyprland session starts with dead input. ReGreet runs on
# wlroots (inside a cage kiosk), so it drives every output natively and hands
# input straight to the Wayland session — none of those failure modes.
#
# The CyberQueer login look is a self-contained stylesheet (regreet.css, loaded
# by ReGreet over an Adwaita-dark base) — picked per-DE from
# desktopenvs/<de>/greetd-regreet/ (see resolve_de_dir below), so hyprdrive's
# glowy "Cosmonaut Shell" skin doesn't get applied on a hyprlua machine (or
# vice versa). The greeter background tracks the wallpaper picker's choice,
# mirrored to a greeter-readable path by the lightdm-greeter-wallpaper.path
# unit (shared, greeter-agnostic despite the name).
#
# Mutually exclusive with the lightdm and ly greeter modules: enabling greetd
# here disables the others and the tty1 getty so exactly one greeter runs.

set -euo pipefail
source "$(dirname "${BASH_SOURCE[0]}")/../../lib/logging.sh"

# apps/ → optional-Modules → modules → setup → repo root (four levels up).
DOTFILES_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/../../../.." && pwd)"
ETC_GREETD="$DOTFILES_DIR/etc-greetd"       # shared infra: config.toml, session script
ETC_LIGHTDM="$DOTFILES_DIR/etc-lightdm"   # shared wallpaper-sync helper + units

# The greeter's VISUAL skin (regreet.toml + regreet.css) is per-DE — hyprdrive's
# "Cosmonaut Shell" (translucent glass, glow, scanlines) and hyprlua's plain
# flat skin are different files under desktopenvs/<de>/greetd-regreet/. Resolve
# which DE this machine is actually running the same way sysupdate.sh's
# _de_source_dir() does: the installed config-updater's SOURCE_BASE is the
# authoritative marker (set by each DE's installer), with a running-session
# fallback for a machine that hasn't installed config-updater yet.
resolve_de_dir() {
    local conf="${XDG_CONFIG_HOME:-$HOME/.config}/config-updater/updater.conf"
    if [[ -f "$conf" ]]; then
        local src
        src=$(awk -F'[[:space:]]*=[[:space:]]*' '/^SOURCE_BASE/{print $2; exit}' "$conf")
        src="${src/#\~/$HOME}"
        [[ -d "${src:-}" ]] && { printf '%s' "$src"; return; }
    fi
    if [[ -n "${HYPRLAND_INSTANCE_SIGNATURE:-}" ]] && pgrep -x niri &>/dev/null; then
        printf '%s' "$DOTFILES_DIR/desktopenvs/niri"
    elif pgrep -x Hyprland &>/dev/null || [[ -n "${HYPRLAND_INSTANCE_SIGNATURE:-}" ]]; then
        printf '%s' "$DOTFILES_DIR/desktopenvs/hyprlua"
    fi
}

DE_DIR="$(resolve_de_dir)"
if [[ -n "$DE_DIR" && -d "$DE_DIR/greetd-regreet" ]]; then
    GREETER_SKIN="$DE_DIR/greetd-regreet"
    log "Using ${GREETER_SKIN#$DOTFILES_DIR/} for the greeter skin (detected DE: $(basename "$DE_DIR"))."
else
    # No DE-specific skin (niri/sway/legacy hyprland) — fall back to
    # hyprdrive's, the original/default look this module has always shipped.
    GREETER_SKIN="$DOTFILES_DIR/desktopenvs/hyprdrive/greetd-regreet"
    warn "No greeter skin for detected DE (${DE_DIR:-unknown}) — falling back to hyprdrive's."
fi

log "Installing greetd + ReGreet + cage..."
sudo pacman -S --noconfirm --needed greetd greetd-regreet cage

# ── cyberqueer GTK theme (optional) ───────────────────────────────────────────
# The greeter's look is driven by regreet.css over an Adwaita base, so this is no
# longer required — but we still ship it so flipping regreet.toml's theme_name
# back to "cyberqueer" works, and so the theme exists on a greeter-only install.
GTK_THEME_SRC="$DOTFILES_DIR/gtk-themes/cyberqueer"
if [[ -d "$GTK_THEME_SRC" ]]; then
    log "Installing cyberqueer GTK theme to /usr/share/themes..."
    sudo cp -r "$GTK_THEME_SRC" /usr/share/themes/
else
    warn "cyberqueer GTK theme not found at $GTK_THEME_SRC — greeter uses the default GTK theme."
fi

# ── Skull fallback background (used until a wallpaper is picked) ───────────────
SKULL_SRC="$DOTFILES_DIR/resources/bg-skull.svg"
SKULL_DST="/usr/share/backgrounds/cyberqueer-skull.png"
if [[ -f "$SKULL_SRC" ]]; then
    command -v rsvg-convert &>/dev/null || sudo pacman -S --noconfirm --needed librsvg
    TMP_BG="$(mktemp /tmp/greeter-skull.XXXXXX.png)"
    trap 'rm -f "$TMP_BG"' EXIT
    rsvg-convert -w 1920 "$SKULL_SRC" -o "$TMP_BG"
    sudo install -Dm644 "$TMP_BG" "$SKULL_DST"
fi

# ── Deploy greetd + ReGreet configuration ─────────────────────────────────────
log "Deploying greetd config, ReGreet config, and session launcher..."
sudo install -Dm644 "$ETC_GREETD/config.toml"        /etc/greetd/config.toml
sudo install -Dm644 "$GREETER_SKIN/regreet.toml"     /etc/greetd/regreet.toml
sudo install -Dm644 "$GREETER_SKIN/regreet.css"      /etc/greetd/regreet.css
sudo install -Dm755 "$ETC_GREETD/regreet-session.sh" /etc/greetd/regreet-session.sh

# ── PAM: password (system-login) + required FIDO/U2F touch ────────────────────
# Replace any pre-existing greetd stack (e.g. a tuigreet securetty+oath one that
# a graphical greeter cannot drive), keeping a timestamped backup.
U2F_HOST="$(hostnamectl --static hostname 2>/dev/null || hostname)"
if [[ -f "$ETC_GREETD/pam.d-greetd" ]]; then
    [[ -f /etc/pam.d/greetd ]] && sudo cp -a /etc/pam.d/greetd "/etc/pam.d/greetd.bak-$(date +%s)"
    log "Deploying /etc/pam.d/greetd (password + FIDO, origin pam://${U2F_HOST})..."
    tmp="$(mktemp)"
    sed "s|@HOST@|${U2F_HOST}|g" "$ETC_GREETD/pam.d-greetd" > "$tmp"
    sudo install -Dm644 "$tmp" /etc/pam.d/greetd
    rm -f "$tmp"
else
    warn "PAM template not found — leaving /etc/pam.d/greetd as-is (FIDO may not work)."
fi

# ── Greeter background tracks the user's desktop wallpaper (shared units) ──────
TARGET_USER="${SUDO_USER:-$(id -un)}"
PREF_MON="${LIGHTDM_GREETER_MONITOR:-}"
WP_HELPER_SRC="$ETC_LIGHTDM/lightdm-greeter-wallpaper"
if [[ -f "$WP_HELPER_SRC" ]]; then
    log "Installing greeter wallpaper-sync helper + units (user: $TARGET_USER)..."
    sudo install -Dm755 "$WP_HELPER_SRC" /usr/local/bin/lightdm-greeter-wallpaper
    for unit in lightdm-greeter-wallpaper.service lightdm-greeter-wallpaper.path; do
        tmp="$(mktemp)"
        sed -e "s|@USER@|${TARGET_USER}|g" -e "s|@PREFERRED_MONITOR@|${PREF_MON}|g" \
            "$ETC_LIGHTDM/$unit" > "$tmp"
        sudo install -Dm644 "$tmp" "/etc/systemd/system/$unit"
        rm -f "$tmp"
    done
    sudo systemctl daemon-reload
    enable_service lightdm-greeter-wallpaper.path
    sudo PREFERRED_MONITOR="$PREF_MON" /usr/local/bin/lightdm-greeter-wallpaper "$TARGET_USER" || true
    if [[ ! -f /usr/share/backgrounds/lightdm-greeter-bg.png && -f "$SKULL_DST" ]]; then
        sudo install -Dm644 "$SKULL_DST" /usr/share/backgrounds/lightdm-greeter-bg.png
    fi
else
    warn "Wallpaper-sync helper not found — greeter background will not track the wallpaper."
    [[ -f "$SKULL_DST" ]] && sudo install -Dm644 "$SKULL_DST" /usr/share/backgrounds/lightdm-greeter-bg.png
fi

# ── Make greetd the sole display manager ──────────────────────────────────────
sudo systemctl disable getty@tty1.service || true
disable_service lightdm.service
disable_service ly@tty1.service
enable_service greetd.service

log "greetd + ReGreet installed and enabled. The Wayland greeter starts on next boot."