#!/usr/bin/env bash

set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
DEFAULT_FFMPEG="$SCRIPT_DIR/ffmpeg"

FFMPEG=""
QUALITY="2"
ENCLIB="libmp3lame"
DELETE_ORIG=1
DRY_RUN=0
EXTRA_ARGS=()

print_help() {
    cat <<'EOF'
Usage: ogg_to_mp3 [OPTIONS] [-- EXTRA_FFMPEG_ARGS]

Converts all .ogg files in the current directory to .mp3 using ffmpeg.

Options:
  -q, --quality <0-9>    Set VBR quality (default: 2)
  -l, --enclib <encoder> Specify MP3 encoder (default: libmp3lame)
  -b, --binary <path>    Use a specific ffmpeg binary instead of ./ffmpeg or $PATH
  -d, --no-delete        Keep original .ogg files after conversion
  -r, --dry-run          Show what would be done without executing
  -h, --help             Display this help message

Extra ffmpeg options:
  Anything after '--' is passed directly to ffmpeg before the output filename.

Examples:
  Convert with default settings:
    ./ogg_to_mp3

  Dry run, showing commands without executing:
    ./ogg_to_mp3 -r

  Use custom encoder and quality:
    ./ogg_to_mp3 -q 0 -l libmp3lame

  Pass extra ffmpeg flags:
    ./ogg_to_mp3 -- -loglevel info -map_metadata 0
EOF
}

# Parse arguments
while [[ $# -gt 0 ]]; do
    case "$1" in
        -h|--help)
            print_help
            exit 0
            ;;
        -q|--quality)
            [[ $# -lt 2 ]] && { echo "Error: $1 requires a value."; exit 1; }
            QUALITY="$2"
            shift 2
            ;;
        -l|--enclib)
            [[ $# -lt 2 ]] && { echo "Error: $1 requires a value."; exit 1; }
            ENCLIB="$2"
            shift 2
            ;;
        -b|--binary)
            [[ $# -lt 2 ]] && { echo "Error: $1 requires a value."; exit 1; }
            FFMPEG="$2"
            shift 2
            ;;
        -d|--no-delete)
            DELETE_ORIG=0
            shift
            ;;
        -r|--dry-run)
            DRY_RUN=1
            shift
            ;;
        --)
            shift
            EXTRA_ARGS=("$@")
            break
            ;;
        *)
            echo "Unknown option: '$1'."
            print_help
            exit 1
            ;;
    esac
done

# Resolve ffmpeg binary
if [[ -n "$FFMPEG" ]]; then
    if [[ ! -x "$FFMPEG" ]]; then
        echo "Error: specified ffmpeg binary '$FFMPEG' not executable"
        exit 1
    fi
else
    if [[ -x "$DEFAULT_FFMPEG" ]]; then
        FFMPEG="$DEFAULT_FFMPEG"
    elif command -v ffmpeg >/dev/null 2>&1; then
        FFMPEG="$(command -v ffmpeg)"
    else
        echo "Error: ffmpeg not found (no ./ffmpeg, no --binary, nothing in PATH)"
        exit 1
    fi
fi

shopt -s nullglob
OGG_FILES=(*.ogg)

if [[ ${#OGG_FILES[@]} -eq 0 ]]; then
    echo "No .ogg files found in current directory."
    exit 0
fi

if [[ $DRY_RUN -eq 1 ]]; then
  echo "DRY RUN:"
fi

for f in "${OGG_FILES[@]}"; do
    out="${f%.ogg}.mp3"

    cmd=(
        "$FFMPEG" -y
        -loglevel error
        -i "$f"
        -c:a "$ENCLIB"
        -q:a "$QUALITY"
        "${EXTRA_ARGS[@]}"
        "$out"
    )

    echo "Converting: '$f' -> '$out'"

    if [[ $DRY_RUN -eq 1 ]]; then
        printf '  ffmpeg '
        for arg in "${cmd[@]:1}"; do
            printf '%q ' "$arg"
        done
        echo
        if [[ $DELETE_ORIG -eq 1 ]]; then
            echo "Script would delete original file ('$f')."
        fi
        continue
    fi

    "${cmd[@]}"

    if [[ $DELETE_ORIG -eq 1 ]]; then
        rm -f "$f"
        echo "Deleted: $f"
    fi
done

echo "Done."