# renderer.py

import subprocess
from pathlib import Path

from config import (
    TEMP_DIR,
    OUTPUT_DIR,
)


# =====================================================
# BUILD CONCAT FILE
# =====================================================

def build_concat_file(
    timeline,
    concat_file=None
):
    """
    timeline:
    [
        {
            "path": "clips/1_A.mp4",
            "duration": 7.1,
            ...
        }
    ]
    """

    if concat_file is None:
        concat_file = (
            TEMP_DIR / "concat.txt"
        )

    concat_file = Path(concat_file)

    with open(
        concat_file,
        "w",
        encoding="utf-8"
    ) as f:

        for scene in timeline:

            clip_path = (
                Path(scene["path"])
                .resolve()
                .as_posix()
            )

            f.write(
                f"file '{clip_path}'\n"
            )

    return str(concat_file)


# =====================================================
# ESTIMATE TIMELINE DURATION
# =====================================================

def estimate_duration(
    timeline
):

    total = 0

    for scene in timeline:
        total += scene["duration"]

    return round(total, 2)


# =====================================================
# RENDER TIMELINE (FAST)
# =====================================================

def render_timeline(
    timeline,
    output_file=None
):
    """
    Fast concat mode.

    Semua clip HARUS:
    - 1280x720
    - 30fps
    - h264
    - yuv420p
    - no audio
    """

    if not timeline:
        raise ValueError(
            "Timeline is empty"
        )

    if output_file is None:

        output_file = (
            OUTPUT_DIR
            / "video_only.mp4"
        )

    output_file = Path(output_file)

    concat_file = build_concat_file(
        timeline
    )

    cmd = [
        "ffmpeg",
        "-y",

        "-f",
        "concat",

        "-safe",
        "0",

        "-i",
        concat_file,

        "-c",
        "copy",

        str(output_file)
    ]

    subprocess.run(
        cmd,
        check=True,
        capture_output=True
    )

    return str(output_file)


# =====================================================
# SAFE RENDER (RE-ENCODE)
# =====================================================

def render_timeline_safe(
    timeline,
    output_file=None
):
    """
    Gunakan jika concat copy gagal.

    Lebih lambat,
    tetapi paling kompatibel.
    """

    if not timeline:
        raise ValueError(
            "Timeline is empty"
        )

    if output_file is None:

        output_file = (
            OUTPUT_DIR
            / "video_only.mp4"
        )

    output_file = Path(output_file)

    concat_file = build_concat_file(
        timeline
    )

    cmd = [
        "ffmpeg",
        "-y",

        "-f",
        "concat",

        "-safe",
        "0",

        "-i",
        concat_file,

        "-c:v",
        "libx264",

        "-preset",
        "ultrafast",

        "-crf",
        "28",

        "-pix_fmt",
        "yuv420p",

        str(output_file)
    ]

    subprocess.run(
        cmd,
        check=True,
        capture_output=True
    )

    return str(output_file)


# =====================================================
# AUTO RENDER
# =====================================================

def render(
    timeline,
    output_file=None
):
    """
    Coba fast mode dulu.
    Jika gagal, fallback ke safe mode.
    """

    try:

        return render_timeline(
            timeline,
            output_file
        )

    except Exception as e:

        print(
            "[Renderer] Fast concat failed:"
        )

        print(e)

        print(
            "[Renderer] Falling back to re-encode..."
        )

        return render_timeline_safe(
            timeline,
            output_file
        )


# =====================================================
# TEST
# =====================================================

if __name__ == "__main__":

    timeline = [

        {
            "path": "clips/1_A.mp4",
            "duration": 7.0
        },

        {
            "path": "clips/2_A.mp4",
            "duration": 7.0
        },

        {
            "path": "clips/3_A.mp4",
            "duration": 7.0
        },

    ]

    print(
        "Estimated:",
        estimate_duration(
            timeline
        )
    )

    result = render(
        timeline
    )

    print(
        "Output:",
        result
    )