#!/bin/bash
# ABOUTME: Transforms an existing Arch+Wayland system into a Moonarch system.
# ABOUTME: Backs up configs, installs packages, deploys all defaults with hard overwrite.

set -euo pipefail

source "$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)/lib.sh"

# ============================================================
# Phase 1: Prerequisites & Detection
# ============================================================

check_not_root
check_pacman

# Require active Wayland session
if [[ "${XDG_SESSION_TYPE:-}" != "wayland" ]] && [[ -z "${WAYLAND_DISPLAY:-}" ]]; then
    err "No active Wayland session detected. Transform requires Wayland."
    exit 1
fi

# Detect conflicting display managers
CONFLICTING_DMS=()
for dm in sddm gdm lightdm ly lemurs; do
    if systemctl is-enabled "${dm}.service" &>/dev/null; then
        CONFLICTING_DMS+=("$dm")
    fi
done

# Detect conflicting packages
CONFLICTING_PKGS=()
if pacman -Qq pulseaudio &>/dev/null && ! pacman -Qq pipewire-pulse &>/dev/null; then
    CONFLICTING_PKGS+=("pulseaudio")
fi

# ============================================================
# Phase 2: Pre-flight Summary
# ============================================================

echo ""
log "============================================"
log "  Moonarch Transform — Pre-flight Summary"
log "============================================"
echo ""

log "Wayland session:    detected"

if [[ ${#CONFLICTING_DMS[@]} -gt 0 ]]; then
    log "Display managers:   ${CONFLICTING_DMS[*]} (will be disabled)"
else
    log "Display managers:   none conflicting"
fi

if [[ ${#CONFLICTING_PKGS[@]} -gt 0 ]]; then
    log "Package conflicts:  ${CONFLICTING_PKGS[*]} (will be removed)"
else
    log "Package conflicts:  none"
fi

echo ""
log "Actions:"
log "  1. Backup ~/.config/, ~/.zshrc, /etc/xdg/ to ~/moonarch-backup-<ts>.tar.gz"
log "  2. Install official + AUR packages"
log "  3. Disable conflicting DMs, enable greetd"
log "  4. Overwrite ALL system configs (/etc/xdg/, /etc/greetd/, ...)"
log "  5. Overwrite ALL user configs (~/.config/)"
log "  6. Configure zsh, GTK themes, firewall, services"
echo ""
err "This will REPLACE your current desktop configuration."
echo ""

if ! confirm "Proceed?"; then
    log "Transform cancelled."
    exit 0
fi

# ============================================================
# Phase 3: Backup
# ============================================================

BACKUP_FILE="$HOME/moonarch-backup-$(date +%Y%m%d-%H%M%S).tar.gz"
log "Creating backup: $BACKUP_FILE"

# Build list of paths that actually exist
BACKUP_PATHS=()
[[ -d "$HOME/.config" ]] && BACKUP_PATHS+=(".config")
[[ -f "$HOME/.zshrc" ]] && BACKUP_PATHS+=(".zshrc")
[[ -d "$HOME/.zshrc.d" ]] && BACKUP_PATHS+=(".zshrc.d")

if [[ ${#BACKUP_PATHS[@]} -gt 0 ]]; then
    tar czf "$BACKUP_FILE" -C "$HOME" "${BACKUP_PATHS[@]}"
    log "  + User configs backed up."
fi

# Backup system XDG separately (needs sudo)
if [[ -d /etc/xdg ]]; then
    SYSTEM_BACKUP="$HOME/moonarch-backup-system-$(date +%Y%m%d-%H%M%S).tar.gz"
    sudo tar czf "$SYSTEM_BACKUP" -C / etc/xdg
    sudo chown "$USER:$USER" "$SYSTEM_BACKUP"
    log "  + System configs backed up: $SYSTEM_BACKUP"
fi

log "Backup complete: $(du -h "$BACKUP_FILE" | cut -f1)"

# ============================================================
# Phase 4: Disable Conflicting Display Managers
# ============================================================

if [[ ${#CONFLICTING_DMS[@]} -gt 0 ]]; then
    log "Disabling conflicting display managers..."
    for dm in "${CONFLICTING_DMS[@]}"; do
        sudo systemctl disable "$dm"
        log "  - $dm disabled"
    done
fi

# ============================================================
# Phase 5: Remove Conflicting Packages
# ============================================================

if pacman -Qq pulseaudio &>/dev/null; then
    log "Removing PulseAudio (replaced by PipeWire)..."
    sudo pacman -Rdd --noconfirm pulseaudio pulseaudio-alsa pulseaudio-bluetooth 2>/dev/null || true
fi

# ============================================================
# Phase 6: Install Packages
# ============================================================

log "Installing official packages..."
if [[ -f "$OFFICIAL_PACKAGES" ]]; then
    # shellcheck disable=SC2046
    sudo pacman -S --needed --noconfirm $(read_packages "$OFFICIAL_PACKAGES")
else
    err "Package list not found: $OFFICIAL_PACKAGES"
    exit 1
fi

# Install paru if not present
if ! command -v paru &>/dev/null; then
    log "Installing paru..."
    PARU_TMPDIR=$(mktemp -d)
    git clone https://aur.archlinux.org/paru.git "$PARU_TMPDIR/paru"
    (cd "$PARU_TMPDIR/paru" && makepkg -si --noconfirm)
    rm -rf "$PARU_TMPDIR"
else
    log "paru already installed."
fi

log "Installing AUR packages..."
if [[ -f "$AUR_PACKAGES" ]]; then
    # shellcheck disable=SC2046
    paru -S --needed --noconfirm $(read_packages "$AUR_PACKAGES")
else
    err "AUR package list not found: $AUR_PACKAGES"
    exit 1
fi

# Moonarch custom paru repo
log "Setting up Moonarch paru repo..."
PARU_CONF="$HOME/.config/paru/paru.conf"
mkdir -p "$(dirname "$PARU_CONF")"
if ! grep -q '\[moonarch\]' "$PARU_CONF" 2>/dev/null; then
    cat >> "$PARU_CONF" <<'EOCONF'
[moonarch]
Url = https://gitea.moonarch.de/nevaforget/moonarch-pkgbuilds.git
EOCONF
    log "  + Moonarch repo added to paru.conf."
else
    log "  ~ Moonarch repo already in paru.conf."
fi

paru -Sy --pkgbuilds --noconfirm
paru -S --needed --noconfirm moonset-git moonlock-git moongreet-git

# Themes
log "Installing themes..."
"$SCRIPT_DIR/install-themes.sh"

# ============================================================
# Phase 7: Deploy System Configs (Hard Overwrite)
# ============================================================

log "Deploying XDG defaults to /etc/xdg/..."
sudo cp -r "$DEFAULTS_DIR/xdg/"* /etc/xdg/
sudo find /etc/xdg/rofi -name "*.sh" -exec chmod +x {} \;

# GTK4 theme symlinks
THEME_NAME="Colloid-Catppuccin"
THEME_GTK4="/usr/share/themes/$THEME_NAME/gtk-4.0"
GTK4_XDG="/etc/xdg/gtk-4.0"

if [[ -d "$THEME_GTK4" ]]; then
    log "Creating system-wide GTK4 symlinks for $THEME_NAME..."
    sudo ln -sf "$THEME_GTK4/gtk-dark.css" "$GTK4_XDG/gtk.css"
    sudo ln -sf "$THEME_GTK4/gtk-dark.css" "$GTK4_XDG/gtk-dark.css"
    sudo rm -f "$GTK4_XDG/assets"
    sudo ln -s "$THEME_GTK4/assets" "$GTK4_XDG/assets"

    # libadwaita only reads user CSS from ~/.config/gtk-4.0/
    USER_GTK4="$HOME/.config/gtk-4.0"
    mkdir -p "$USER_GTK4"
    ln -sf "$THEME_GTK4/gtk-dark.css" "$USER_GTK4/gtk.css"
    ln -sf "$THEME_GTK4/gtk-dark.css" "$USER_GTK4/gtk-dark.css"
    rm -f "$USER_GTK4/assets"
    ln -s "$THEME_GTK4/assets" "$USER_GTK4/assets"
else
    err "GTK4 theme not found: $THEME_GTK4 — libadwaita apps will use fallback theme."
fi

# gsettings
log "Setting gsettings for GTK theme..."
gsettings set org.gnome.desktop.interface gtk-theme "$THEME_NAME"
gsettings set org.gnome.desktop.interface color-scheme 'prefer-dark'
gsettings set org.gnome.desktop.interface icon-theme 'Colloid-Grey-Catppuccin-Dark'
gsettings set org.gnome.desktop.interface font-name 'UbuntuSans Nerd Font 11'

# Helper scripts
log "Installing Moonarch helper scripts to /usr/local/bin/..."
sudo install -m 755 "$DEFAULTS_DIR/bin/moonarch-"* /usr/local/bin/

# awww compatibility symlinks
if command -v awww &>/dev/null && ! command -v swww &>/dev/null; then
    log "Creating swww -> awww compatibility symlinks..."
    sudo ln -s /usr/bin/awww /usr/local/bin/swww
    sudo ln -s /usr/bin/awww-daemon /usr/local/bin/swww-daemon
fi

# Zsh configuration
log "Installing Zsh default config..."
sudo cp "$DEFAULTS_DIR/shell/zshrc" /etc/zsh/zshrc.moonarch

if ! grep -q "zshrc.moonarch" /etc/zsh/zshrc 2>/dev/null; then
    echo '# Moonarch defaults (overridden by ~/.zshrc)' | sudo tee -a /etc/zsh/zshrc > /dev/null
    echo '[[ ! -f "$HOME/.zshrc" ]] && source /etc/zsh/zshrc.moonarch' | sudo tee -a /etc/zsh/zshrc > /dev/null
fi

# For transform: always create a fresh .zshrc that sources Moonarch defaults
log "Creating ~/.zshrc with Moonarch defaults..."
mkdir -p "$HOME/.zshrc.d"
echo "# Load Moonarch defaults, add custom overrides in ~/.zshrc.d/ or below" > "$HOME/.zshrc"
echo "source /etc/zsh/zshrc.moonarch" >> "$HOME/.zshrc"

# greetd / moongreet
log "Configuring greetd + moongreet..."
sudo mkdir -p /etc/greetd
sudo cp "$DEFAULTS_DIR/etc/greetd/config.toml" /etc/greetd/config.toml
sudo mkdir -p /etc/moongreet
sudo cp "$DEFAULTS_DIR/etc/moongreet/moongreet.toml" /etc/moongreet/moongreet.toml

# Niri greeter config (if present)
if [[ -f "$DEFAULTS_DIR/etc/greetd/niri-greeter.kdl" ]]; then
    sudo cp "$DEFAULTS_DIR/etc/greetd/niri-greeter.kdl" /etc/greetd/niri-greeter.kdl
fi

# Wallpaper
log "Installing default wallpaper..."
sudo mkdir -p /usr/share/moonarch
sudo cp "$DEFAULTS_DIR/backgrounds/wallpaper.jpg" /usr/share/moonarch/wallpaper.jpg

# ============================================================
# Phase 8: Deploy User Configs (Hard Overwrite)
# ============================================================

# Replace user-level XDG configs for all apps Moonarch manages
log "Deploying XDG configs to ~/.config/ (overwrite)..."
for src_dir in "$DEFAULTS_DIR/xdg/"*/; do
    app_name="$(basename "$src_dir")"
    # gtk-4.0 is handled separately with Colloid-Catppuccin theme symlinks (Phase 7)
    [[ "$app_name" == "gtk-4.0" ]] && continue
    dest_dir="$HOME/.config/$app_name"
    rm -rf "$dest_dir"
    cp -r "$src_dir" "$dest_dir"
    log "  + $app_name/"
done

# Deploy user defaults (overwrite, no existence check)
log "Deploying user config defaults to ~/.config/ (overwrite)..."
USER_DEFAULTS_DIR="$DEFAULTS_DIR/user"
if [[ -d "$USER_DEFAULTS_DIR" ]]; then
    for src_dir in "$USER_DEFAULTS_DIR"/*/; do
        app_name="$(basename "$src_dir")"
        dest_dir="$HOME/.config/$app_name"
        mkdir -p "$dest_dir"
        find "$src_dir" -type f -print0 | while IFS= read -r -d '' src_file; do
            rel_path="${src_file#"$src_dir"}"
            dest_file="$dest_dir/$rel_path"
            mkdir -p "$(dirname "$dest_file")"
            cp "$src_file" "$dest_file"
            log "  + $app_name/$rel_path"
        done
    done
fi

# ============================================================
# Phase 9: Services & Finalization
# ============================================================

log "Enabling services..."
SERVICES=(
    "NetworkManager"
    "bluetooth"
    "docker"
    "greetd"
    "systemd-timesyncd"
    "ufw"
    "auto-cpufreq"
)

for service in "${SERVICES[@]}"; do
    if systemctl list-unit-files "${service}.service" &>/dev/null; then
        sudo systemctl enable "$service"
        log "  + $service"
    else
        log "  ~ $service not found, skipped."
    fi
done

# Set shell to zsh
if [[ "$SHELL" != */zsh ]]; then
    log "Setting default shell to zsh..."
    chsh -s "$(which zsh)"
fi

# Firewall
log "Configuring UFW..."
sudo ufw default deny incoming
sudo ufw default allow outgoing
sudo ufw --force enable

# Docker group
if ! groups | grep -q docker; then
    log "Adding user to docker group..."
    sudo usermod -aG docker "$USER"
fi

# Directories
mkdir -p "$HOME/Pictures/Screenshots"
mkdir -p "$HOME/Pictures/Wallpaper"

# moonarch-update symlink
log "Creating moonarch-update command..."
sudo ln -sf "$PROJECT_DIR/scripts/update.sh" /usr/local/bin/moonarch-update

# ============================================================
# Phase 10: Done
# ============================================================

echo ""
log "============================================"
log "  Moonarch transform complete!"
log "============================================"
echo ""
log "Your previous config is backed up at:"
log "  $BACKUP_FILE"
if [[ -n "${SYSTEM_BACKUP:-}" ]]; then
    log "  $SYSTEM_BACKUP"
fi
echo ""
log "Next steps:"
log "  1. Reboot (greetd replaces your previous display manager)"
log "  2. Place wallpapers in ~/Pictures/Wallpaper/"
log "  3. rustup default stable"
log "  4. User overrides in ~/.config/ or ~/.zshrc.d/"
echo ""
err "Do NOT log out — your previous DM is disabled. Reboot instead."
echo ""