#!/bin/bash

# ==============================================================================
# FFmpeg Wrapper Script for Volume Detection
#
# This script acts as a wrapper for the real ffmpeg binary.
# It's designed to handle cases where 'ffmpeg -filter:a volumedetect'
# doesn't output 'mean_volume:' (e.g., for image files or videos without audio).
#
# If 'mean_volume:' is not found in the real ffmpeg's stderr output,
# it injects 'mean_volume: 0 dB' into the stderr stream.
#
# Setup:
# 1. Rename your original ffmpeg binary.
#    Example: mv /usr/bin/ffmpeg /usr/bin/ffmpeg.bin
# 2. Place this script at the original ffmpeg's path.
#    Example: cp this_script.sh /usr/bin/ffmpeg
# 3. Make this script executable.
#    Example: chmod +x /usr/bin/ffmpeg
# 4. Ensure REAL_FFMPEG_BINARY points to your renamed ffmpeg binary.
# ==============================================================================

# --- Configuration ---
# Point this to the actual ffmpeg binary after you've renamed it.
# For example: /usr/bin/ffmpeg.bin or /usr/local/bin/ffmpeg.bin
REAL_FFMPEG_BINARY="/usr/bin/ffmpeg.bin" 
# ---------------------

# Check if the real ffmpeg binary exists
if [ ! -f "$REAL_FFMPEG_BINARY" ]; then
    echo "Error: Real ffmpeg binary not found at $REAL_FFMPEG_BINARY" >&2
    echo "Please ensure you've renamed your original ffmpeg (e.g., to ffmpeg.bin)" >&2
    echo "and updated the REAL_FFMPEG_BINARY path in this script." >&2
    exit 1
fi

# Create a temporary file to capture stderr from the real ffmpeg command
TEMP_ERR_FILE=$(mktemp)

# Ensure the temporary file is deleted when the script exits
trap "rm -f $TEMP_ERR_FILE" EXIT

# Execute the real ffmpeg with all arguments passed to this script.
# Redirect its stdout to /dev/null as volumedetect output is on stderr.
# Redirect its stderr to our temporary file.
"$REAL_FFMPEG_BINARY" "$@" >/dev/null 2>"$TEMP_ERR_FILE"

# Capture the exit code of the real ffmpeg command
REAL_FFMPEG_EXIT_CODE=$?

# Read the content of the temporary stderr file
FFMPEG_STDERR_CONTENT=$(cat "$TEMP_ERR_FILE")

# Check if "mean_volume:" is present in the captured stderr content
if echo "$FFMPEG_STDERR_CONTENT" | grep -q "mean_volume:"; then
    # If found, print the original stderr content to our stderr
    echo "$FFMPEG_STDERR_CONTENT" >&2
else
    # If not found, print the original stderr content
    echo "$FFMPEG_STDERR_CONTENT" >&2
    # Then inject the default mean_volume line
    echo "[ffmpeg-wrapper] Injected: mean_volume: 0 dB (original output lacked volume info)" >&2 # For debugging
    echo "mean_volume: 0 dB" >&2
fi

# Exit with the same exit code as the real ffmpeg command
exit $REAL_FFMPEG_EXIT_CODE