app/services/video_service.py

import os, uuid, requests
from gtts import gTTS
from mutagen.mp3 import MP3
from moviepy.editor import ImageClip, concatenate_videoclips, AudioFileClip
from moviepy.config import change_settings

# ✅ Force MoviePy temp directory to /tmp
change_settings({"FFMPEG_BINARY": "ffmpeg"})
os.environ["TMPDIR"] = "/tmp"

def generate_video_file(script: str, duration: int = None) -> str:
    base_tmp = "/tmp/video"
    audio_tmp = "/tmp/audio"
    tmp_images = "/tmp/video_tmp"

    os.makedirs(base_tmp, exist_ok=True)
    os.makedirs(audio_tmp, exist_ok=True)
    os.makedirs(tmp_images, exist_ok=True)

    video_filename = f"video_{uuid.uuid4().hex}.mp4"
    video_path = os.path.join(base_tmp, video_filename)
    audio_path = os.path.join(audio_tmp, f"audio_{uuid.uuid4().hex}.mp3")

    # Step 1: Generate TTS audio
    tts = gTTS(text=script, lang='en')
    tts.save(audio_path)

    # Step 2: Get audio duration
    audio = MP3(audio_path)
    audio_duration = max(audio.info.length, 3.0)

    # Step 3: Fetch Unsplash images
    images = fetch_unsplash_images(script, count=3)
    if not images:
        raise Exception("No images found from Unsplash for the prompt")

    clips, tmp_files = [], []
    per_image_duration = audio_duration / len(images)

    for url in images:
        img_data = requests.get(url).content
        tmp_file = os.path.join(tmp_images, f"tmp_{uuid.uuid4().hex}.jpg")
        tmp_files.append(tmp_file)
        with open(tmp_file, "wb") as f:
            f.write(img_data)

        clip = ImageClip(tmp_file).resize(height=720).set_duration(per_image_duration)
        clips.append(clip)

    # Step 4: Build final video
    final_clip = concatenate_videoclips(clips, method="compose").set_duration(audio_duration)
    final_clip = final_clip.set_audio(AudioFileClip(audio_path))

    # ✅ Step 5: Export video with all temp files in /tmp
    final_clip.write_videofile(
        video_path,
        fps=24,
        codec="libx264",
        audio_codec="aac",
        threads=4,
        preset="ultrafast",
        temp_audiofile="/tmp/temp-audio.m4a",
        remove_temp=True,
        ffmpeg_params=["-avoid_negative_ts", "make_zero"]
    )

    # Cleanup images
    for file in tmp_files:
        try:
            os.remove(file)
        except:
            pass

    return video_filename