#!/bin/bash
# Music Parallelism Prevention Script
# Prevents listening to music while doing focus work (coding, gaming)
#
# When a focus application (VS Code, Steam games, etc.) is detected alongside
# a music streaming service (YouTube Music, Spotify, etc.), the music is stopped.
#
# Music is fine when running alone - only killed when combined with focus apps.

set -euo pipefail

# Source common library for shared functions
SCRIPT_DIR="$(dirname "$(readlink -f "$0")")"
if [[ -f "$SCRIPT_DIR/../../lib/common.sh" ]]; then
	# shellcheck source=../../lib/common.sh
	source "$SCRIPT_DIR/../../lib/common.sh"
elif [[ -f "/usr/local/lib/common.sh" ]]; then
	# shellcheck source=/usr/local/lib/common.sh
	# Deployed to /usr/local/lib at install time; no in-repo copy exists at that
	# absolute path for the linter to follow.
	# shellcheck disable=SC1091
	source "/usr/local/lib/common.sh"
else
	echo "ERROR: common.sh library not found"
	exit 1
fi

# Configuration
LOG_DIR="${XDG_STATE_HOME:-$HOME/.local/state}/music-parallelism"
mkdir -p "$LOG_DIR" 2>/dev/null || true
export LOG_FILE="$LOG_DIR/music-parallelism.log"
CHECK_INTERVAL=15
FAST_CHECK_INTERVAL=5
IDLE_CHECK_INTERVAL=30
ENFORCEMENT_COOLDOWN=20
PROC_ROOT="${PROC_ROOT:-/proc}"

MUSIC_PROCESS_NAMES=(
	"youtube-music"
	"spotify"
	"tidal"
	"deezer"
	"amazon music"
)

# Override focus apps with extended list for this script
FOCUS_APPS_WINDOWS=(
	# IDEs and code editors - match window titles
	"Visual Studio Code"
	"VSCodium"
	"Cursor"
	"IntelliJ IDEA"
	"PyCharm"
	"WebStorm"
	"CLion"
	"Rider"
	"Sublime Text"
	"Atom"
	"Neovide"
	# Gaming
	"Steam"
	# Creative apps
	"Blender"
	"Godot"
	"Unity"
	"Unreal Editor"
)

# Music streaming services - browser tabs or electron apps
# These will be killed when focus apps are detected
MUSIC_SERVICES=(
	# YouTube Music specific patterns (NOT regular YouTube)
	"music.youtube.com"
	"youtube-music" # Electron app
	"YouTube Music" # Window title
	# Spotify
	"spotify"
	"Spotify"
	# Tidal
	"tidal"
	"TIDAL"
	# Deezer
	"deezer"
	# Amazon Music
	"Amazon Music"
	"amazon music"
	# Apple Music (web)
	"music.apple.com"
	# SoundCloud
	"soundcloud.com"
	# Pandora
	"pandora.com"
)

readonly MUSIC_WINDOWS_PATTERN='YouTube Music|music\.youtube\.com|music\.apple\.com|soundcloud\.com|pandora\.com|deezer\.com|tidal\.com'
readonly ACTIVE_NO_MUSIC_INTERVAL=15
readonly ACTIVE_AFTER_KILL_INTERVAL=5
readonly IDLE_CHECK_INTERVAL=30
MUSIC_FOUND_PROCESS=0
MUSIC_FOUND_WINDOW=0

wait_seconds() {
	local timeout_s=$1
	local start_ts end_ts elapsed_s remaining_s

	if [[ -n ${MUSIC_PARALLELISM_TEST_WAIT_LOG:-} ]]; then
		printf '%s\n' "$timeout_s" >>"$MUSIC_PARALLELISM_TEST_WAIT_LOG"
		if [[ ${MUSIC_PARALLELISM_TEST_EXIT_AFTER_WAIT:-0} -eq 1 ]]; then
			exit 99
		fi
		return 0
	fi

	printf -v start_ts '%(%s)T' -1
	IFS= read -r -t "$timeout_s" || true
	printf -v end_ts '%(%s)T' -1

	elapsed_s=$((end_ts - start_ts))
	if ((elapsed_s < timeout_s)); then
		remaining_s=$((timeout_s - elapsed_s))
		sleep "$remaining_s"
	fi
}

contains_music_process() {
	local comm_file comm_lower token_lower

	for comm_file in "$PROC_ROOT"/[0-9]*/comm; do
		[[ -r $comm_file ]] || continue
		read -r comm_lower <"$comm_file" || continue
		comm_lower=${comm_lower,,}

		for token_lower in "${MUSIC_PROCESS_NAMES[@]}"; do
			if [[ $comm_lower == *"${token_lower,,}"* ]]; then
				return 0
			fi
		done
	done

	return 1
}

# Check if any music service is running and return its details (OPTIMIZED: batch pgrep calls)
find_music_services() {
	local found_services=()
	MUSIC_FOUND_PROCESS=0
	MUSIC_FOUND_WINDOW=0

	# Check processes using /proc (fork-free)
	if contains_music_process; then
		MUSIC_FOUND_PROCESS=1
		found_services+=("music process")
	fi

	# Check windows (use optimized is_focus_app_running logic: single xdotool regex call)
	if command -v xdotool &>/dev/null && [[ ${#MUSIC_SERVICES[@]} -gt 0 ]]; then
		if xdotool search --name "$MUSIC_WINDOWS_PATTERN" &>/dev/null 2>&1; then
			MUSIC_FOUND_WINDOW=1
			found_services+=("music service (window)")
		fi
	fi

	if [[ ${#found_services[@]} -gt 0 ]]; then
		printf '%s\n' "${found_services[@]}"
		return 0
	fi
	return 1
}

# Kill music services
kill_music_services() {
	local use_cached_detection="${1:-0}"
	local killed=false
	local window_pattern='YouTube Music|music\.youtube\.com|music\.apple\.com|soundcloud\.com|pandora\.com|deezer\.com|tidal\.com'
	local should_check_windows=1
	local should_check_processes=1

	if [[ $use_cached_detection -eq 1 ]]; then
		should_check_windows=$MUSIC_FOUND_WINDOW
		should_check_processes=$MUSIC_FOUND_PROCESS
	fi

	# Close browser tabs for web-based music services via one xdotool search
	if [[ $should_check_windows -eq 1 ]] && command -v xdotool &>/dev/null; then
		local windows wid
		windows=$(xdotool search --name "$window_pattern" 2>/dev/null || true)
		for wid in $windows; do
			[[ -n $wid ]] || continue
			xdotool windowclose "$wid" 2>/dev/null || true
			killed=true
		done
	fi

	# Kill app processes with /proc scan + builtin kill (fork-free in hot path)
	if [[ $should_check_processes -eq 1 ]]; then
		local comm_file pid comm_lower token_lower
		for comm_file in "$PROC_ROOT"/[0-9]*/comm; do
			[[ -r $comm_file ]] || continue
			read -r comm_lower <"$comm_file" || continue
			comm_lower=${comm_lower,,}
			pid=${comm_file#"$PROC_ROOT"/}
			pid=${pid%%/*}

			for token_lower in "${MUSIC_PROCESS_NAMES[@]}"; do
				if [[ $comm_lower == *"${token_lower,,}"* ]]; then
					if [[ $PROC_ROOT != "/proc" ]]; then
						# Test mode (fake proc tree): mark as killed without signaling host PIDs.
						killed=true
					elif kill -9 "$pid" 2>/dev/null; then
						killed=true
					fi
					break
				fi
			done
		done
	fi

	if $killed; then
		return 0
	fi
	return 1
}

# Send notification to user
notify_user() {
	local focus_app="$1"
	local message="Music stopped - focus mode active ($focus_app detected)"

	# Try to send desktop notification
	if command -v notify-send &>/dev/null; then
		notify-send -u normal -t 5000 "🎵 Music Parallelism" "$message" 2>/dev/null || true
	fi

	log_message "$message"
}

# Instant monitoring loop - uses polling at high frequency ONLY when focus app is detected
# When focus app active: checks every 0.5s. When idle: checks every 3s. Reduces fork overhead.
# OPTIMIZATION: Single batched pgrep call instead of multiple separate calls
instant_monitor_loop() {
	local next_enforcement_ts=0
	local current_ts=0
	local focus_app=""
	local sleep_interval="$IDLE_CHECK_INTERVAL"

	log_message "=== Music Parallelism INSTANT Monitor Started ==="
	log_message "Focus apps (windows): ${FOCUS_APPS_WINDOWS[*]}"
	log_message "Focus apps (processes): ${FOCUS_APPS_PROCESSES[*]}"
	log_message "Polling: ${FAST_CHECK_INTERVAL}s active, ${ACTIVE_NO_MUSIC_INTERVAL}s stable-focus, ${IDLE_CHECK_INTERVAL}s idle, ${ENFORCEMENT_COOLDOWN}s enforcement cooldown"

	while true; do
		if focus_app=$(is_focus_app_running 2>/dev/null); then
			current_ts=$(get_timestamp)
			if ((current_ts >= next_enforcement_ts)); then
				if find_music_services >/dev/null 2>&1; then
					if kill_music_services 1; then
						notify_user "$focus_app"
						log_message "INSTANT KILL: Music services terminated"
						sleep_interval="$ACTIVE_AFTER_KILL_INTERVAL"
					fi
				else
					sleep_interval="$ACTIVE_NO_MUSIC_INTERVAL"
				fi
				next_enforcement_ts=$((current_ts + ENFORCEMENT_COOLDOWN))
			else
				sleep_interval="$ACTIVE_NO_MUSIC_INTERVAL"
			fi
		else
			next_enforcement_ts=0
			sleep_interval="$IDLE_CHECK_INTERVAL"
		fi

		wait_seconds "$sleep_interval"
	done
}

# Main monitoring loop
monitor_loop() {
	log_message "=== Music Parallelism Monitor Started ==="
	log_message "Focus apps (windows): ${FOCUS_APPS_WINDOWS[*]}"
	log_message "Focus apps (processes): ${FOCUS_APPS_PROCESSES[*]}"
	log_message "Music services monitored: ${MUSIC_SERVICES[*]}"
	log_message "Check interval: ${CHECK_INTERVAL}s"

	while true; do
		# Check if a focus app is running
		local focus_app
		if focus_app=$(is_focus_app_running); then
			# Focus app detected, check for music services
			local music_services
			if music_services=$(find_music_services); then
				log_message "Conflict detected: Focus app '$focus_app' running with music services"
				log_message "Active music services: $music_services"

				# Kill the music services
				if kill_music_services 1; then
					notify_user "$focus_app"
				fi
			fi
		fi

		wait_seconds "$CHECK_INTERVAL"
	done
}

# Show status
show_status() {
	echo "Music Parallelism Monitor Status"
	echo "================================="
	echo ""

	echo "Focus Applications (window-based detection):"
	local focus_running=false

	# Check windows (OPTIMIZED: single xdotool call with combined regex)
	if command -v xdotool &>/dev/null && [[ ${#FOCUS_APPS_WINDOWS[@]} -gt 0 ]]; then
		local regex
		printf -v regex '%s|' "${FOCUS_APPS_WINDOWS[@]}"
		regex="${regex%|}" # strip trailing |
		if xdotool search --name "$regex" &>/dev/null 2>&1; then
			echo "  ✓ Focus window detected"
			focus_running=true
		fi
	fi

	# Check processes using shared /proc-based helper (fork-free)
	if is_focus_app_running >/dev/null 2>&1; then
		echo "  ✓ Focus process running"
		focus_running=true
	fi

	if ! $focus_running; then
		echo "  (none detected)"
	fi

	echo ""
	echo "Music Services:"
	local music_running=false
	if music_services=$(find_music_services 2>/dev/null); then
		echo "$music_services" | while read -r svc; do
			echo "  ♪ $svc (RUNNING)"
		done
		music_running=true
	fi
	if ! $music_running; then
		echo "  (none detected)"
	fi

	echo ""
	if $focus_running && $music_running; then
		echo "⚠️  CONFLICT: Focus app and music running together!"
		echo "   Music would be killed in monitoring mode."
	elif $focus_running; then
		echo "✓ Focus mode active (no music playing)"
	elif $music_running; then
		echo "✓ Music playing (no focus app detected - this is fine)"
	else
		echo "✓ Idle (nothing detected)"
	fi
}

# Show usage
show_usage() {
	echo "Music Parallelism Prevention Script"
	echo "===================================="
	echo ""
	echo "Usage: $0 [command]"
	echo ""
	echo "Commands:"
	echo "  monitor  - Start monitoring (default, checks every ${CHECK_INTERVAL}s)"
	echo "  instant  - Instant monitoring (${FAST_CHECK_INTERVAL}s active / ${IDLE_CHECK_INTERVAL}s idle)"
	echo "  status   - Show current status of focus apps and music services"
	echo "  kill     - Immediately kill all music services"
	echo "  help     - Show this help message"
	echo ""
	echo "Description:"
	echo "  This script prevents multitasking between focus work and music."
	echo "  When a focus application (VS Code, Steam, etc.) is detected"
	echo "  alongside a music streaming service, the music is stopped."
	echo ""
	echo "  Music is allowed when no focus apps are running."
	echo ""
}

# Main
case "${1:-instant}" in
monitor | start | run)
	monitor_loop
	;;
instant | fast)
	instant_monitor_loop
	;;
status)
	show_status
	;;
kill)
	log_message "Manual kill requested"
	if kill_music_services; then
		echo "Music services killed"
	else
		echo "No music services found to kill"
	fi
	;;
help | -h | --help)
	show_usage
	;;
*)
	echo "Unknown command: $1"
	show_usage
	exit 1
	;;
esac