# shellcheck shell=bash
#------------------------------------------
# lib/common.sh — shared helpers
#
# Sourced by setup.sh and by every module. Modules source it directly, so a
# module can be run standalone for testing:
#     DE=none TWM=niri bash modules/twm/niri.sh
#------------------------------------------

# Guard against double-sourcing (setup.sh and a module can both pull it in)
if [[ -n "${_SB_COMMON_LOADED:-}" ]]; then
    return 0
fi
_SB_COMMON_LOADED=1

#------------------------------------------
# Colors (printf-safe, no tput)
#------------------------------------------
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[0;33m'
CYAN='\033[0;36m'
PURPLE='\033[0;35m'
BLUE='\033[0;34m'
GRAY='\033[0;37m'
BOLD='\033[1m'
RESET='\033[0m'

# Disable colors if output is not a terminal
# (PURPLE/BLUE/BOLD defined for future use; shellcheck has no way to know that)
# shellcheck disable=SC2034
if [ ! -t 1 ]; then
    RED='' GREEN='' YELLOW='' CYAN='' PURPLE='' BLUE='' GRAY='' BOLD='' RESET=''
fi

color_yellow() { printf "%b%s%b\n" "$YELLOW" "$*" "$RESET"; }
color_cyan()   { printf "%b%s%b\n" "$CYAN"   "$*" "$RESET"; }
color_red()    { printf "%b%s%b\n" "$RED"    "$*" "$RESET"; }
color_green()  { printf "%b%s%b\n" "$GREEN"  "$*" "$RESET"; }
color_gray()   { printf "%b%s%b\n" "$GRAY"   "$*" "$RESET"; }

#------------------------------------------
# Log levels
#------------------------------------------
info()  { color_cyan   "  $*"; }
ok()    { color_green  "  $*"; }
warn()  { color_yellow "  $*"; }
err()   { color_red    "  $*" >&2; }
step()  { printf "\n"; color_yellow "$*"; }
rule()  { printf "%s\n" "----------------------------------------------------------------"; }

#------------------------------------------
# Debug pausing
#------------------------------------------
is_debug() { [[ "${DEBUG_MODE:-false}" == "true" ]]; }

pause_if_debug() {
    if is_debug; then
        printf "\n"
        color_yellow "----------------------------------------------------------------"
        read -rp "Section complete. Press [Enter] to continue, or [q] to abort: " debug_choice
        if [[ "${debug_choice,,}" == "q" ]]; then
            color_red "Script aborted by user."
            exit 1
        fi
        color_yellow "----------------------------------------------------------------"
        printf "\n"
    fi
}

#------------------------------------------
# Package helpers (dnf5)
#------------------------------------------
install_packages() {
    # -y           : no prompts
    # weak deps on : keep default behaviour, stated explicitly so it is greppable
    sudo dnf install -y --setopt=install_weak_deps=True "$@"
}

# Same, but a missing/renamed package warns instead of aborting the whole run.
# Use for anything that is a nice-to-have rather than load-bearing.
install_optional() {
    sudo dnf install -y --setopt=install_weak_deps=True "$@" \
        || warn "Optional packages not installed: $*"
}

pkg_installed() {
    local p
    for p in "$@"; do
        rpm -q "$p" &>/dev/null || return 1
    done
    return 0
}

remove_packages() {
    local packages_to_remove=()
    for pkg in "$@"; do
        if pkg_installed "$pkg"; then
            packages_to_remove+=("$pkg")
        else
            color_gray "  Package '$pkg' not installed. Skipping removal."
        fi
    done

    if [ ${#packages_to_remove[@]} -gt 0 ]; then
        info "Removing packages: ${packages_to_remove[*]}"
        sudo dnf remove -y "${packages_to_remove[@]}"
    fi
}

# dnf comps group. Fail loudly with the real group list rather than letting
# dnf's generic "no match" scroll past.
install_group() {
    local group="$1"
    if ! dnf group info "$group" >/dev/null 2>&1; then
        err "No such dnf group: @$group"
        err "Available groups on this system:"
        dnf group list --hidden 2>/dev/null | sed 's/^/    /' >&2 || true
        return 1
    fi
    sudo dnf group install -y "$group"
}

# Try each candidate group/environment in turn; first one that exists wins.
install_group_any() {
    local g
    for g in "$@"; do
        if dnf group info "$g" >/dev/null 2>&1; then
            info "Using dnf group: @$g"
            sudo dnf group install -y "$g"
            return 0
        fi
    done
    err "None of these dnf groups exist: $*"
    dnf group list --hidden 2>/dev/null | sed 's/^/    /' >&2 || true
    return 1
}

#------------------------------------------
# Third-party repos
#------------------------------------------
add_terra_repo() {
    if pkg_installed terra-release; then
        ok "Terra repository already installed."
        return 0
    fi
    info "Adding Terra repository (Fyra Labs)..."
    # Terra's own instructions use --nogpgcheck for the bootstrap package;
    # once terra-release is in place the repo itself is signature-checked.
    sudo dnf install -y --nogpgcheck \
        --repofrompath 'terra,https://repos.fyralabs.com/terra$releasever' \
        terra-release
}

add_rpmfusion_repo() {
    local rel
    rel=$(rpm -E %fedora)
    if pkg_installed rpmfusion-free-release rpmfusion-nonfree-release; then
        ok "RPM Fusion already installed."
        return 0
    fi
    info "Enabling RPM Fusion (free + nonfree) for Fedora ${rel}..."
    sudo dnf install -y \
        "https://mirrors.rpmfusion.org/free/fedora/rpmfusion-free-release-${rel}.noarch.rpm" \
        "https://mirrors.rpmfusion.org/nonfree/fedora/rpmfusion-nonfree-release-${rel}.noarch.rpm"
}

#------------------------------------------
# Fonts
#------------------------------------------
# Nerd Fonts are not in the Fedora repos, so pull the release zip from GitHub
# into the user's font dir. Idempotent: skipped if the family is already there.
install_nerd_font() {
    local family="${1:-JetBrainsMono}"
    local dest="${HOME}/.local/share/fonts/NerdFonts-${family}"
    local url="https://github.com/ryanoasis/nerd-fonts/releases/latest/download/${family}.zip"

    if [[ -d "$dest" ]] && compgen -G "$dest/*.ttf" >/dev/null; then
        ok "Nerd Font ${family} already installed."
        return 0
    fi

    info "Installing Nerd Font ${family}..."
    local tmp
    tmp=$(mktemp -d)

    if ! curl -fsSL -o "$tmp/${family}.zip" "$url"; then
        warn "Could not download ${family} Nerd Font. Skipping."
        rm -rf "$tmp"
        return 0
    fi

    if ! command -v unzip >/dev/null 2>&1; then
        install_packages unzip
    fi

    mkdir -p "$dest"
    unzip -qo "$tmp/${family}.zip" -d "$dest"
    rm -rf "$tmp"

    fc-cache -f "$dest" >/dev/null 2>&1 || true
    ok "Nerd Font ${family} installed to $dest"
}


#------------------------------------------
# System: SELinux, Btrfs, snapper
#------------------------------------------
# Permanently disable SELinux. Destructive-ish: warn loudly, and remind the
# user a reboot is needed for the change to take effect.
disable_selinux() {
    # FSTAB/SELINUX file overridable for testing on non-Fedora hosts
    local cfg="${SELINUX_CONFIG:-/etc/selinux/config}"
    if [[ -f "$cfg" ]] && grep -q '^SELINUX=disabled' "$cfg"; then
        ok "SELinux already disabled in $cfg."
        return 0
    fi
    warn "Disabling SELinux permanently. This removes a significant layer of"
    warn "system protection. Only do this if you specifically need it."
    if [[ -f "$cfg" ]]; then
        sudo cp "$cfg" "${cfg}.bkp.$(date +%F)"
        sudo sed -i 's/^SELINUX=.*/SELINUX=disabled/' "$cfg"
    else
        printf 'SELINUX=disabled\nSELINUXTYPE=targeted\n' | sudo tee "$cfg" >/dev/null
    fi
    ok "SELINUX=disabled written to $cfg (backup saved). Reboot to apply."
}

# Show the btrfs layout, then make sure every btrfs fstab entry compresses
# with zstd. The sed variant from the SysGuides guide appends ,compress=zstd:1
# after the subvol= option; we guard it so re-runs cannot stack duplicates.
ensure_btrfs_compression() {
    local fstab="${FSTAB_FILE:-/etc/fstab}"
    info "Current btrfs subvolumes on /:"
    sudo btrfs subvolume list / 2>/dev/null | sed 's/^/    /' || warn "btrfs subvolume list failed (not btrfs?)"

    info "fstab btrfs entries:"
    grep ' btrfs ' "$fstab" | sed 's/^/    /' || true

    local fixed=0 line
    # Only touch btrfs lines that have a subvol= option and no compress= yet.
    while IFS= read -r line; do
        if grep -q ' btrfs ' <<<"$line" && grep -q 'subvol=' <<<"$line" && ! grep -q 'compress=' <<<"$line"; then
            fixed=$((fixed+1))
        fi
    done < "$fstab"

    if (( fixed == 0 )); then
        ok "All btrfs fstab entries already carry a compress= option (or none exist)."
        return 0
    fi

    info "Adding compress=zstd:1 to ${fixed} btrfs fstab entrie(s)..."
    # Backup once per run, then apply the SysGuides sed to every qualifying line.
    sudo cp "$fstab" "$fstab.bkp.$(date +%F-%H%M)"
    sudo sed -i '/ btrfs / s/subvol=[^ ,]*/&,compress=zstd:1/' "$fstab"
    ok "fstab updated. Remount or reboot for compression to take effect:"
    info "    sudo mount -o remount /  &&  sudo mount -o remount /home"
}

# Full snapshot setup via the SysGuides installer (snapper + grub-btrfs +
# DNF5 pre/post snapshot actions). The installer re-validates btrfs itself.
setup_snapper() {
    if pkg_installed snapper && [[ -d /.snapshots ]]; then
        ok "Snapper already configured (config for / exists)."
        return 0
    fi
    if ! findmnt -n -o FSTYPE / 2>/dev/null | grep -q btrfs; then
        warn "Root filesystem is not btrfs; skipping snapshot setup."
        return 0
    fi
    info "Setting up snapper + grub-btrfs (SysGuides installer)..."
    local tmp
    tmp=$(mktemp -d)
    git clone --depth 1 https://github.com/SysGuides/sysguides-snapper-fedora "$tmp/sysguides" \
        || { err "Could not clone the SysGuides installer."; rm -rf "$tmp"; return 1; }
    ( cd "$tmp/sysguides" && ./install.sh )
    local rc=$?
    rm -rf "$tmp"
    if (( rc == 0 )); then
        ok "Snapper + grub-btrfs installed. Every dnf transaction now gets a pre/post snapshot."
        info "Try it:  snapper ls   |   snapper status 1..2   |   sudo snapper undochange 1..2"
    fi
    return $rc
}