#!/usr/bin/env bash
set -euo pipefail

# any2av1mkv - Convert provided files to MKV with AV1 video (VAAPI on AMD),
# keeping ALL audio tracks, subtitles (including PGS), and attachments.
#
# Default is bitrate-controlled VBR, tuned for 1080p and "not inflating".
#
# Usage:
#   any2av1mkv input1.mkv input2.mp4 "weird name.avi"
#   any2av1mkv *                  # skips directories
#
# Options:
#   -d, --dry-run        print ffmpeg command(s) only
#   --no-skip            overwrite output if it already exists
#   --cqp                use constant-quality mode instead of VBR
#   --audio-encode aac   re-encode ALL audio tracks to AAC (default: copy)
#   -h, --help
#
# Env vars:
#   DEV=/dev/dri/renderD128
#
# VBR mode (default):
#   B=3500k              target video bitrate (1080p 10-bit starting point)
#   MAX=5000k            max video bitrate
#   BUF=10000k           VBV buffer
#
# CQP mode (with --cqp):
#   QP=42                higher = smaller / lower quality (try 40-46 for 1080p)

DEV="${DEV:-/dev/dri/renderD128}"

B="${B:-1500k}"
MAX="${MAX:-2200k}"
BUF="${BUF:-4400k}"

QP="${QP:-46}"

dry_run=0
skip_existing=1
audio_mode="acc" # or "copy"
use_cqp=0

args=()
while [[ $# -gt 0 ]]; do
    case "$1" in
    -d | --dry-run)
        dry_run=1
        shift
        ;;
    --no-skip)
        skip_existing=0
        shift
        ;;
    --cqp)
        use_cqp=1
        shift
        ;;
    --audio-encode)
        [[ "${2:-}" == "aac" ]] || {
            echo "Error: --audio-encode only supports: aac" >&2
            exit 1
        }
        audio_mode="aac"
        shift 2
        ;;
    -h | --help)
        sed -n '1,220p' "$0"
        exit 0
        ;;
    --)
        shift
        args+=("$@")
        break
        ;;
    *)
        args+=("$1")
        shift
        ;;
    esac
done

command -v ffmpeg >/dev/null 2>&1 || {
    echo "Error: ffmpeg not found." >&2
    exit 1
}

if [[ ${#args[@]} -eq 0 ]]; then
    echo "No input files. Provide file names/globs (e.g. *.mkv, *)."
    exit 2
fi

for f in "${args[@]}"; do
    [[ -e "$f" ]] || {
        echo "Skip (missing): $f"
        continue
    }
    [[ -f "$f" ]] || {
        echo "Skip (not a file): $f"
        continue
    }

    base="${f##*/}"
    stem="${base%.*}"
    out_dir="$(dirname -- "$f")"
    out="${out_dir}/${stem}.av1.mkv"

    if [[ $skip_existing -eq 1 && -e "$out" ]]; then
        echo "Skip (exists): $out"
        continue
    fi

    echo "Transcoding: $f -> $out"

    if [[ "$audio_mode" == "aac" ]]; then
        aopts=(-c:a aac -b:a 192k)
    else
        aopts=(-c:a copy)
    fi

    # Video options:
    # - Use p010le to preserve 10-bit sources (and avoid 8-bit nv12 forcing).
    # - If your source is 8-bit, VAAPI will still handle it; p010le is generally safe.
    if [[ $use_cqp -eq 1 ]]; then
        vopts=(-c:v av1_vaapi -rc_mode CQP -qp "$QP")
    else
        vopts=(-c:v av1_vaapi -rc_mode VBR -b:v "$B" -maxrate "$MAX" -bufsize "$BUF")
    fi

    cmd=(
        ffmpeg -hide_banner -nostdin -y
        -vaapi_device "$DEV"
        -i "$f"
        -map 0
        -vf 'format=p010le,hwupload'
        "${vopts[@]}"
        "${aopts[@]}"
        -c:s copy
        -c:t copy
        -c:d copy
        "$out"
    )

    if [[ $dry_run -eq 1 ]]; then
        printf '%q ' "${cmd[@]}"
        printf '\n'
    else
        "${cmd[@]}"
    fi
done