#!/usr/bin/env bash

set -Eeuo pipefail

OUTPUT_DIR="video_result"
FAILED_LIST="$OUTPUT_DIR/failed.txt"
JOBS=2

mkdir -p "$OUTPUT_DIR"
: > "$FAILED_LIST"

#############################################
# 인코딩
#############################################

encode() {
    local input="$1"
    local filename name output
    local abr abr_k

    filename=$(basename "$input")
    name="${filename%.*}"
    output="$OUTPUT_DIR/$name.mp4"

    echo
    echo "▶ $filename"

    # 이미 존재
    if [[ -f "$output" ]]; then
        echo "  이미 존재 -> 건너뜀"
        return
    fi

    #########################################
    # 오디오 확인 및 옵션 구성
    #########################################

    local -a AUDIO_ARGS=()
    local -a MAP_ARGS=(-map 0:v:0)

    if ffprobe -v error \
        -select_streams a:0 \
        -show_entries stream=index \
        -of csv=p=0 "$input" | grep -q .; then

        echo "  오디오 : 있음"

        abr=$(ffprobe -v error \
            -select_streams a:0 \
            -show_entries stream=bit_rate \
            -of default=noprint_wrappers=1:nokey=1 \
            "$input" || true)

        if [[ -z "$abr" || "$abr" == "N/A" ]]; then
            abr_k=112
        else
            abr_k=$((abr / 1000))
            (( abr_k < 1 )) && abr_k=112
            (( abr_k > 112 )) && abr_k=112
        fi

        AUDIO_ARGS=(-c:a aac -b:a "${abr_k}k")
        MAP_ARGS+=(-map 0:a:0)

        echo "  오디오 bitrate : ${abr_k}k"

    else
        echo "  오디오 : 없음"
    fi

    #########################################
    # FFmpeg
    #########################################

    if ffmpeg \
        -hide_banner \
        -loglevel warning \
        -stats \
        -y \
        -i "$input" \
        "${MAP_ARGS[@]}" \
        -map_metadata 0 \
        -map_metadata:s:v 0:s:v \
        -vf "scale=1280:1280:force_original_aspect_ratio=decrease:force_divisible_by=2,fps=30" \
        -c:v libx265 \
        -preset fast \
        -crf 32 \
        -pix_fmt yuv420p \
        -threads 0 \
        -tag:v hvc1 \
        "${AUDIO_ARGS[@]}" \
        -movflags +faststart+use_metadata_tags \
        "$output"
    then

        #####################################
        # 원본 메타데이터 복사
        #####################################

        if exiftool \
            -overwrite_original \
            -tagsFromFile "$input" \
            -all:all \
            --unsafe \
            "$output"; then

            # 파일 시간 보존
            touch -r "$input" "$output"

            echo "✔ 완료"

        else
            rm -f "$output"
            echo "$filename" >> "$FAILED_LIST"
            echo "✖ 메타데이터 복사 실패"
        fi

    else
        rm -f "$output"
        echo "$filename" >> "$FAILED_LIST"
        echo "✖ FFmpeg 실패"
    fi
}

export -f encode
export OUTPUT_DIR FAILED_LIST

#############################################
# Ctrl+C
#############################################

trap '
    echo
    echo "중단됨"
    pkill -P $$ ffmpeg 2>/dev/null || true
    exit 1
' INT

#############################################
# 병렬 인코딩
#############################################

find . -maxdepth 1 -type f \
    \( -iname "*.mp4" -o \
       -iname "*.mov" -o \
       -iname "*.mkv" -o \
       -iname "*.avi" -o \
       -iname "*.wmv" -o \
       -iname "*.flv" -o \
       -iname "*.webm" -o \
       -iname "*.m4v" \) \
    -print0 |
xargs -0 -n1 -P "$JOBS" bash -c 'encode "$0"'

#############################################
# 결과
#############################################

echo
echo "========================================"

SUCCESS=$(find "$OUTPUT_DIR" -maxdepth 1 -type f -name "*.mp4" | wc -l | tr -d ' ')
echo "성공 : $SUCCESS"

if [[ -s "$FAILED_LIST" ]]; then
    echo "실패 : $(wc -l < "$FAILED_LIST")"
    cat "$FAILED_LIST"
else
    echo "실패 : 0"
    rm -f "$FAILED_LIST"
fi

echo "========================================"