#!/bin/bash
set -u

# ---------------------------------------------------------------------------
# Config
# ---------------------------------------------------------------------------
threshold=${1:-30}
AUR_REPO="aur-local"
# stock kernel package -> your custom build of it. Add or remove entries freely.
declare -A KERNELS=(
    [linux]="linux-custom"
    [linux-lts]="linux-lts-custom"
    [linux-zen]="linux-zen-custom"
)
state_dir="${XDG_STATE_HOME:-$HOME/.local/state}/update-notify"

[[ $threshold =~ ^[0-9]+$ ]] || { echo "Threshold must be a number" >&2; exit 1; }
mkdir -p "$state_dir"

# notify-send from cron/systemd needs the session bus address
export DBUS_SESSION_BUS_ADDRESS="${DBUS_SESSION_BUS_ADDRESS:-unix:path=/run/user/$(id -u)/bus}"

# ---------------------------------------------------------------------------
# Helpers
# ---------------------------------------------------------------------------

# Send a notification only if its body changed since last time for this key.
notify_once() {
    local key=$1 title=$2 body=$3
    local file="$state_dir/$key"
    if [[ -f $file && $(<"$file") == "$body" ]]; then
        return 0
    fi
    printf '%s' "$body" > "$file"
    notify-send "$title" "$body"
}

# Forget a key so the next occurrence notifies again.
clear_state() {
    rm -f "$state_dir/$1"
}

# If $1 has a pending update, print its new version and return 0.
# checkupdates lines look like: "pkgname oldver -> newver"
pending_version() {
    local pkg=$1 item new
    for item in "${arch_list[@]}"; do
        if [[ $item == "$pkg "* ]]; then
            read -r _ _ _ new <<< "$item"
            printf '%s\n' "$new"
            return 0
        fi
    done
    return 1
}

# ---------------------------------------------------------------------------
# Gather updates
# ---------------------------------------------------------------------------

# Fetch checkupdates once. Exit codes: 0 = updates, 2 = none, 1 = error.
checkupdates_out=$(checkupdates 2>/dev/null)
checkupdates_rc=$?
if (( checkupdates_rc == 1 )); then
    echo "checkupdates failed (network or sync problem?)" >&2
fi

arch_list=()
if [[ -n $checkupdates_out ]]; then
    mapfile -t arch_list <<< "$checkupdates_out"
fi
arch_updates=${#arch_list[@]}

aur_updates=0
if command -v aur >/dev/null 2>&1; then
    aur_updates=$(aur repo -u -d "$AUR_REPO" 2>/dev/null | wc -l)
fi
updates=$((arch_updates + aur_updates))

# ---------------------------------------------------------------------------
# Kernel check: the stock kernel updated, but your custom build didn't
# ---------------------------------------------------------------------------
for stock_pkg in "${!KERNELS[@]}"; do
    custom_pkg=${KERNELS[$stock_pkg]}

    # Only relevant if the custom kernel is installed and has no pending update itself
    if pacman -Q "$custom_pkg" >/dev/null 2>&1 && ! pending_version "$custom_pkg" >/dev/null; then
        if stock_ver=$(pending_version "$stock_pkg"); then
            notify_once "kernel-$stock_pkg" "Kernel update available: $stock_pkg" \
                "Rebuild $custom_pkg ($stock_pkg $stock_ver)"
            continue
        fi
    fi
    clear_state "kernel-$stock_pkg"
done

# ---------------------------------------------------------------------------
# General updates threshold
# ---------------------------------------------------------------------------
if (( updates >= threshold )); then
    notify_once "updates" "Updates available" "Arch: $arch_updates, AUR: $aur_updates"

    hints=(
        "git-monitor|Check git packages|Use git-monitor for git packages updates"
        "fwupdmgr|Check firmware|Use fwupdmgr to check for firmware updates"
    )
    for hint in "${hints[@]}"; do
        IFS='|' read -r cmd title body <<< "$hint"
        if command -v "$cmd" >/dev/null 2>&1; then
            notify_once "hint-$cmd" "$title" "$body"
        fi
    done
else
    clear_state "updates"
    clear_state "hint-git-monitor"
    clear_state "hint-fwupdmgr"
fi
