#!/bin/bash
# ABOUTME: Moonarch system updater — updates system, repo and defaults.
# ABOUTME: Should be run regularly to keep the system in sync.

set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
PROJECT_DIR="$(dirname "$SCRIPT_DIR")"
OFFICIAL_PACKAGES="$PROJECT_DIR/packages/official.txt"
AUR_PACKAGES="$PROJECT_DIR/packages/aur.txt"
DEFAULTS_DIR="$PROJECT_DIR/defaults"

# --- Helper functions ---

log() {
    echo -e "\e[1;34m[Moonarch]\e[0m $*"
}

err() {
    echo -e "\e[1;31m[Moonarch ERROR]\e[0m $*" >&2
}

read_packages() {
    grep -v '^\s*#' "$1" | grep -v '^\s*$'
}

confirm() {
    read -r -p "$1 [y/N] " response
    [[ "$response" =~ ^[yY]$ ]]
}

# --- Prerequisites ---

if [[ $EUID -eq 0 ]]; then
    err "Do NOT run as root."
    exit 1
fi

# --- 1. Update Moonarch repo ---

log "=== Update Moonarch repo ==="

cd "$PROJECT_DIR"
if git rev-parse --is-inside-work-tree &>/dev/null; then
    LOCAL=$(git rev-parse HEAD)
    git fetch origin
    REMOTE=$(git rev-parse @{u} 2>/dev/null || echo "$LOCAL")

    if [[ "$LOCAL" != "$REMOTE" ]]; then
        log "Updates available."
        git --no-pager log --oneline "$LOCAL".."$REMOTE"
        echo ""
        if confirm "Update repo?"; then
            git pull --ff-only
            log "Repo updated."
        else
            log "Repo update skipped."
        fi
    else
        log "Repo is up to date."
    fi
else
    log "Not a git repo — repo update skipped."
fi

# --- 2. Update system packages ---

log "=== Update system packages ==="

if confirm "Run pacman -Syu?"; then
    sudo pacman -Syu
else
    log "System update skipped."
fi

if command -v paru &>/dev/null; then
    if confirm "Update AUR packages (paru -Sua)?"; then
        paru -Sua
    else
        log "AUR update skipped."
    fi
fi

# --- 3. Install missing packages ---

log "=== Reconcile package lists ==="

if [[ -f "$OFFICIAL_PACKAGES" ]]; then
    MISSING_OFFICIAL=$(comm -23 <(read_packages "$OFFICIAL_PACKAGES" | sort) <(pacman -Qqe | sort) || true)
    if [[ -n "$MISSING_OFFICIAL" ]]; then
        log "Missing official packages:"
        echo "$MISSING_OFFICIAL"
        if confirm "Install?"; then
            # shellcheck disable=SC2086
            sudo pacman -S --needed --noconfirm $MISSING_OFFICIAL
        fi
    else
        log "All official packages installed."
    fi
fi

if [[ -f "$AUR_PACKAGES" ]] && command -v paru &>/dev/null; then
    MISSING_AUR=$(comm -23 <(read_packages "$AUR_PACKAGES" | sort) <(pacman -Qqe | sort) || true)
    if [[ -n "$MISSING_AUR" ]]; then
        log "Missing AUR packages:"
        echo "$MISSING_AUR"
        if confirm "Install?"; then
            # shellcheck disable=SC2086
            paru -S --needed --noconfirm $MISSING_AUR
        fi
    else
        log "All AUR packages installed."
    fi
fi

# --- 4. Update defaults ---

log "=== Update defaults ==="

# XDG Defaults
CHANGED_XDG=false
if ! diff -rq "$DEFAULTS_DIR/xdg/" /etc/xdg/ --exclude='*.pyc' &>/dev/null 2>&1; then
    CHANGED_XDG=true
fi

if $CHANGED_XDG; then
    log "XDG defaults have changed."
    diff -rq "$DEFAULTS_DIR/xdg/" /etc/xdg/ --exclude='*.pyc' 2>/dev/null | head -20 || true
    echo ""
    if confirm "Deploy XDG defaults to /etc/xdg/?"; then
        sudo cp -r "$DEFAULTS_DIR/xdg/"* /etc/xdg/
        log "XDG defaults updated."
    fi
else
    log "XDG defaults are up to date."
fi

# Binaries
CHANGED_BIN=false
for bin in "$DEFAULTS_DIR/bin/moonarch-"*; do
    name=$(basename "$bin")
    if ! cmp -s "$bin" "/usr/local/bin/$name" 2>/dev/null; then
        CHANGED_BIN=true
        break
    fi
done

if $CHANGED_BIN; then
    log "Moonarch binaries have changed."
    for bin in "$DEFAULTS_DIR/bin/moonarch-"*; do
        name=$(basename "$bin")
        if ! cmp -s "$bin" "/usr/local/bin/$name" 2>/dev/null; then
            log "  ~ $name"
        fi
    done
    if confirm "Deploy binaries to /usr/local/bin/?"; then
        sudo install -m 755 "$DEFAULTS_DIR/bin/moonarch-"* /usr/local/bin/
        log "Binaries updated."
    fi
else
    log "Binaries are up to date."
fi

# Zsh
if ! cmp -s "$DEFAULTS_DIR/shell/zshrc" /etc/zsh/zshrc.moonarch 2>/dev/null; then
    log "Zsh defaults have changed."
    if confirm "Update Zsh defaults?"; then
        sudo cp "$DEFAULTS_DIR/shell/zshrc" /etc/zsh/zshrc.moonarch
        log "Zsh defaults updated."
    fi
else
    log "Zsh defaults are up to date."
fi

# --- 5. Orphaned packages ---

log "=== Orphaned packages ==="

ORPHANS=$(pacman -Qdtq 2>/dev/null || true)
if [[ -n "$ORPHANS" ]]; then
    log "Orphaned packages found:"
    echo "$ORPHANS"
    if confirm "Remove?"; then
        # shellcheck disable=SC2086
        sudo pacman -Rsn --noconfirm $ORPHANS
    fi
else
    log "No orphaned packages."
fi

# --- Done ---

log ""
log "============================================"
log "  Moonarch update complete!"
log "============================================"