"""Encodes a PNG frame sequence (Godot movie writer output) into an H.264 MP4 with Blender's
bundled FFmpeg, so no separate FFmpeg installation is needed.

Run: blender -b --python-exit-code 1 --python tools/luneraria/encode_video.py -- <frame_dir> <out.mp4> [fps] [scale]
     scale (default 1.0) shrinks the output, e.g. 0.5 for 960x540.
"""
import sys
from pathlib import Path
import bpy

args = sys.argv[sys.argv.index('--') + 1:]
frames_dir, out = Path(args[0]), Path(args[1])
fps = int(args[2]) if len(args) > 2 else 30
scale = float(args[3]) if len(args) > 3 else 1.0
files = sorted(p for p in frames_dir.iterdir() if p.suffix.lower() == '.png')
if not files:
    raise SystemExit('ENCODE_FAILED: no frames in %s' % frames_dir)

bpy.ops.wm.read_factory_settings(use_empty=True)
scene = bpy.context.scene
scene.sequence_editor_create()
strips = scene.sequence_editor.strips if hasattr(scene.sequence_editor, 'strips') else scene.sequence_editor.sequences
strip = strips.new_image(name='frames', filepath=str(files[0]), channel=1, frame_start=1)
for f in files[1:]:
    strip.elements.append(f.name)
image = bpy.data.images.load(str(files[0]))
width, height = image.size
scene.render.resolution_x = int(width * scale) // 2 * 2
scene.render.resolution_y = int(height * scale) // 2 * 2
scene.render.resolution_percentage = 100
scene.render.fps = fps
scene.frame_start = 1
scene.frame_end = len(files)
scene.render.image_settings.media_type = 'VIDEO' if hasattr(scene.render.image_settings, 'media_type') else scene.render.image_settings.file_format
scene.render.image_settings.file_format = 'FFMPEG'
scene.render.ffmpeg.format = 'MPEG4'
scene.render.ffmpeg.codec = 'H264'
scene.render.ffmpeg.constant_rate_factor = 'MEDIUM'
scene.render.ffmpeg.ffmpeg_preset = 'GOOD'
scene.render.ffmpeg.audio_codec = 'NONE'
scene.render.use_sequencer = True
scene.render.filepath = str(out)
out.parent.mkdir(parents=True, exist_ok=True)
bpy.ops.render.render(animation=True)
print('ENCODE_DONE', out, len(files), 'frames', '%dx%d' % (scene.render.resolution_x, scene.render.resolution_y), '%d fps' % fps, flush=True)