#!/bin/env bash

# Strict mode: exit on errors, undefined variables, and pipe failures
set -euo pipefail

# --- Configuration ---
APP_ID="com.github.th_ch.youtube_music"
REPO_OWNER="th-ch"
REPO_NAME="youtube-music"
DOWNLOAD_DIR="$HOME/.local/share/youtube-music-updater"
ARCH="x86_64" # Assuming x86_64, adjust if needed
SCRIPT_NAME="update-youtube-music" # Base name for service/timer files
SYSTEMD_USER_DIR="$HOME/.config/systemd/user"
SERVICE_FILE="$SYSTEMD_USER_DIR/$SCRIPT_NAME.service"
TIMER_FILE="$SYSTEMD_USER_DIR/$SCRIPT_NAME.timer"


# --- Helper Functions ---
info() {
    echo "[INFO] $1"
}

warn() {
    echo "[WARN] $1" >&2
}

error() {
    echo "[ERROR] $1" >&2
    exit 1
}

check_command() {
    command -v "$1" >/dev/null 2>&1
}

# --- Systemd Timer Setup Function ---
setup_timer() {
    info "Starting systemd timer setup..."

    # Check if systemctl --user is available
    if ! check_command "systemctl"; then
        error "systemctl command not found. Cannot manage systemd user units."
    fi
    # Attempt a basic user command to ensure user instance is running
    if ! systemctl --user list-units > /dev/null 2>&1; then
         error "Cannot connect to systemd user instance. Ensure it's running (loginctl enable-linger $USER may be needed if you're not logged in graphically)."
    fi


    # Check if files already exist
    if [[ -f "$SERVICE_FILE" && -f "$TIMER_FILE" ]]; then
        info "Systemd service ($SERVICE_FILE) and timer ($TIMER_FILE) files already exist."
        info "To apply changes or restart, you can use:"
        info "  systemctl --user daemon-reload"
        info "  systemctl --user restart $SCRIPT_NAME.timer"
        exit 0
    fi

    # Get the absolute path to this script
    # Using BASH_SOURCE is generally reliable when the script is executed directly
    # realpath might not be installed, so try BASH_SOURCE first
    local script_path
    if [[ -n "${BASH_SOURCE[0]}" ]]; then
        script_path=$(realpath "${BASH_SOURCE[0]}")
    else
        # Fallback attempt if BASH_SOURCE is empty (less common)
        script_path=$(realpath "$0") || error "Could not determine the absolute path of this script. Cannot create systemd service."
    fi

    info "Script absolute path determined as: $script_path"
    info "Creating systemd user directory: $SYSTEMD_USER_DIR"
    mkdir -p "$SYSTEMD_USER_DIR"

    # Create Service File
    info "Creating service file: $SERVICE_FILE"
    # Quoting 'EOF' prevents variable expansion inside the heredoc
    cat << 'EOF' > "$SERVICE_FILE"
[Unit]
Description=Update YouTube Music Flatpak
After=network-online.target
Wants=network-online.target

[Service]
Type=oneshot
# Note: %f in ExecStart will be replaced by the script path
ExecStart=%f
EOF
    # Replace placeholder %f with the actual script path (escape slashes for sed)
    local escaped_script_path
    escaped_script_path=$(echo "$script_path" | sed 's/\//\\\//g')
    sed -i "s/%f/$escaped_script_path/" "$SERVICE_FILE"


    # Create Timer File
    info "Creating timer file: $TIMER_FILE"
    cat << 'EOF' > "$TIMER_FILE"
[Unit]
Description=Run YouTube Music Flatpak updater daily
# Ensures the timer unit itself is correctly tracked
RefuseManualStart=no
RefuseManualStop=no

[Timer]
# Run daily at 3 AM; adjust as needed (e.g., '*-*-* 03:00:00')
# Or simply 'daily' for midnight
OnCalendar=daily
# Run shortly after boot if missed, and randomized delay to avoid thundering herd
RandomizedDelaySec=10m
Persistent=true

[Install]
WantedBy=timers.target
EOF

    info "Reloading systemd user daemon..."
    if systemctl --user daemon-reload; then
        info "Daemon reloaded successfully."
    else
        warn "systemctl daemon-reload failed. Manual reload might be needed."
    fi

    info "Enabling and starting the timer ($SCRIPT_NAME.timer)..."
    # Use enable --now to both enable on boot and start immediately
    if systemctl --user enable --now "$SCRIPT_NAME.timer"; then
        info "Timer enabled and started successfully."
        info "Update check will run daily (check timer file for exact schedule)."
        info "Check status with: systemctl --user status $SCRIPT_NAME.timer"
    else
        error "Failed to enable or start the timer. Check systemctl/journalctl logs for errors."
    fi

    exit 0 # Exit after successful setup
}


# --- Argument Parsing ---
if [[ "${1:-}" == "--setup-timer" ]]; then
    setup_timer
    # setup_timer exits on its own, but added exit here for clarity
    exit 0
fi

# --- Main Script ---
info "Starting YouTube Music update check..."

# --- Offer Timer Setup ---
# Check if timer exists during a normal run and suggest setup if not
if ! [[ -f "$TIMER_FILE" ]]; then
    # Check if we are in an interactive terminal before suggesting
    if [[ -t 1 ]]; then
         # Try to get script name robustly
         current_script_name="${BASH_SOURCE[0]:-$0}"
         info "Systemd timer file ($TIMER_FILE) not found."
         info "To set up automatic daily updates, run this script with the --setup-timer flag:"
         info "  $current_script_name --setup-timer"
         # Add a small pause so the user sees the message
         sleep 1
    fi
fi

# Create download directory
mkdir -p "$DOWNLOAD_DIR"
info "Using download directory: $DOWNLOAD_DIR"

# Fetch latest version info from GitHub releases
LATEST_YML_URL="https://github.com/$REPO_OWNER/$REPO_NAME/releases/latest/download/latest-linux.yml"
info "Fetching latest version info from $LATEST_YML_URL"
latest_yml_content=$(curl -sL "$LATEST_YML_URL") || error "Failed to fetch latest version info. Check network or URL."

latest_version=$(echo "$latest_yml_content" | grep 'version:' | awk '{ print $2 }')
if [ -z "$latest_version" ]; then
    error "Could not parse latest version from the yml file."
fi
info "Latest available version: $latest_version"

# Check currently installed version
installed_version=$(flatpak info "$APP_ID" 2>/dev/null | grep Version | awk '{print $2}' || echo "none")

if [[ "$installed_version" == "$latest_version" ]]; then
    info "YouTube Music is already up to date (version $installed_version)."
    exit 0
elif [[ "$installed_version" == "none" ]]; then
    info "YouTube Music is not currently installed."
else
    info "Installed version ($installed_version) differs from latest ($latest_version). Proceeding with update."
fi

# Determine downloader (prefer aria2c)
downloader=""
if check_command "aria2c"; then
    info "Using aria2c for download."
    downloader="aria2c"
else
    warn "aria2c not found. Attempting to install or find fallback..."
    # (Installation attempt/recommendation logic remains the same)
    if check_command "brew"; then
        info "Detected Homebrew. Trying 'brew install aria2'..."
        if brew install aria2; then
            if check_command "aria2c"; then
                 info "Successfully installed aria2c via Homebrew."
                 downloader="aria2c"
            else
                 warn "Homebrew install command succeeded but aria2c still not found."
            fi
        else
            warn "Failed to install aria2 via Homebrew."
        fi
    elif check_command "apt"; then
        warn "Detected apt. Recommend installing aria2 manually: sudo apt update && sudo apt install aria2"
    elif check_command "dnf"; then
        warn "Detected dnf. Recommend installing aria2 manually: sudo dnf install aria2"
    elif check_command "pacman"; then
        warn "Detected pacman. Recommend installing aria2 manually: sudo pacman -S aria2"
    elif check_command "zypper"; then
        warn "Detected zypper. Recommend installing aria2 manually: sudo zypper install aria2"
    else
        warn "Could not find brew or common Linux package managers to install aria2."
    fi

    if [[ -z "$downloader" ]]; then
        if check_command "wget"; then
            warn "Falling back to wget for download."
            downloader="wget"
        else
            error "Neither aria2c nor wget found. Cannot download the file."
        fi
    fi
fi

# Prepare download URL and filename
FILENAME="YouTube-Music-$latest_version-$ARCH.flatpak"
DOWNLOAD_URL="https://github.com/$REPO_OWNER/$REPO_NAME/releases/latest/download/$FILENAME"
OUTPUT_PATH="$DOWNLOAD_DIR/$FILENAME"

info "Downloading YouTube Music version $latest_version..."

# Download using the selected tool
download_success=false
if [[ "$downloader" == "aria2c" ]]; then
    if aria2c -c -x 1 -s 1 --dir="$DOWNLOAD_DIR" -o "$FILENAME" "$DOWNLOAD_URL"; then
        download_success=true
    else
        warn "aria2c download failed."
    fi
elif [[ "$downloader" == "wget" ]]; then
    # Using -nv (non-verbose) instead of --show-progress for better timer logs
    if wget -c -nv -O "$OUTPUT_PATH" "$DOWNLOAD_URL"; then
        download_success=true
    else
        warn "wget download failed."
    fi
fi

if ! $download_success; then
     error "Download failed. Please check network connection or logs."
fi

info "Download complete: $OUTPUT_PATH"

# Install the Flatpak
info "Removing previous version (if exists)..."
flatpak remove --user --assumeyes --noninteractive "$APP_ID" || true

info "Installing new version $latest_version..."
if flatpak install --user --assumeyes --noninteractive "$OUTPUT_PATH"; then
    info "Successfully installed YouTube Music version $latest_version."
else
    error "Flatpak installation failed."
fi

# Cleanup old downloads
info "Cleaning up old downloads..."
find "$DOWNLOAD_DIR" -maxdepth 1 -name "YouTube-Music-*.flatpak" -not -name "$FILENAME" -delete

info "Update process finished successfully."
exit 0

strings ~/.local/share/flatpak/app/com.github.th_ch.youtube_music/current/active/files/lib/com.github.th_ch.youtube_music/resources/app.asar | rg -o -U '"name":\s*"youtube-music"(?:.|\n)+"version":\s*"(.+)"'