"""gzip JSON responses, leaving streamed exports uncompressed.

flask-compress 1.24 has no per-view exempt API; instead ``COMPRESS_STREAMS=False`` leaves
streamed responses (the contract and contract_term ``stream_with_context`` exports) uncompressed
so they are not buffered into memory before being sent.
"""

from flask import Flask
from flask_compress import Compress

from core.config import Config

compress = Compress()


def setup_compression(app: Flask, config: type[Config]) -> None:
    """Enable Accept-Encoding-negotiated gzip on ``app`` for sizable JSON/text responses.

    Always on: gzip is harmless and only applied when the client advertises gzip support.
    Streamed responses are excluded so the chunked exports are never buffered for compression.
    """
    app.config.setdefault(
        'COMPRESS_MIMETYPES', ['application/json', 'text/html', 'text/plain']
    )
    app.config.setdefault('COMPRESS_MIN_SIZE', 500)
    app.config.setdefault('COMPRESS_LEVEL', 5)
    app.config.setdefault('COMPRESS_STREAMS', False)
    compress.init_app(app)