"""
File serving utilities for FastAPI app.
"""
from fastapi.responses import FileResponse, HTMLResponse, StreamingResponse

HTML_EXTS = [".html", ".htm"]
HTML_GZ_EXT = ".html.gz"
IMAGE_EXTS = [".png", ".jpg", ".jpeg", ".gif", ".bmp", ".webp", ".svg"]
PDF_EXT = ".pdf"

def serve_html_file(file_resp, file_path):
    content = file_resp.read() if hasattr(file_resp, "read") else file_resp
    if isinstance(content, bytes):
        content = content.decode("utf-8", errors="replace")
    return HTMLResponse(content, media_type="text/html; charset=utf-8")

def serve_html_gz_file(file_resp, file_path):
    import io
    import unicodedata
    content = file_resp.read() if hasattr(file_resp, "read") else file_resp
    if not isinstance(content, bytes):
        content = bytes(content)
    safe_filename = file_path[:-3]
    try:
        safe_filename.encode('ascii')
    except UnicodeEncodeError:
        safe_filename = unicodedata.normalize('NFKD', safe_filename).encode('ascii', 'ignore').decode('ascii')
        if not safe_filename:
            safe_filename = 'file.html'
    headers = {
        "Content-Encoding": "gzip",
        "Content-Disposition": f"inline; filename={safe_filename}"
    }
    return StreamingResponse(io.BytesIO(content), media_type="text/html", headers=headers)

def serve_image_file(file_resp, file_path):
    import tempfile, os
    from starlette.background import BackgroundTask
    def get_image_bytes(file_resp):
        if hasattr(file_resp, "read"):
            return file_resp.read()
        return file_resp if isinstance(file_resp, bytes) else bytes(file_resp)
    image_bytes = get_image_bytes(file_resp)
    ext = file_path.split(".")[-1].lower()
    media_type = f"image/{'jpeg' if ext == 'jpg' else ext}"
    with tempfile.NamedTemporaryFile(delete=False, suffix=f'.{ext}') as tmp:
        tmp.write(image_bytes)
        tmp_path = tmp.name
    def cleanup():
        try:
            os.remove(tmp_path)
        except Exception:
            pass
    return FileResponse(tmp_path, media_type=media_type, filename=file_path, background=BackgroundTask(cleanup))

def serve_binary_file(file_resp, file_path, media_type=None):
    return FileResponse(file_resp, filename=file_path, media_type=media_type)