"""
HTTP Connection Pool Manager.
Optimized for 150 concurrent users.
Reuses TCP connections to external APIs.
"""

import requests
from requests.adapters import HTTPAdapter
from urllib3.util.retry import Retry
from config import (
    GPT_POOL_SIZE, TTS_POOL_SIZE, MISTRAL_POOL_SIZE,
    TRANSCRIPT_POOL_SIZE, CLOUDINARY_POOL_SIZE, BOARD_PROCESSOR_POOL_SIZE
)


def _create_session(pool_size, pool_block=True, retries=2):
    """
    Create a requests.Session with connection pooling.
    pool_block=True prevents overwhelming external APIs.
    """
    session = requests.Session()

    retry_strategy = Retry(
        total=retries,
        backoff_factor=0.5,
        status_forcelist=[502, 503, 504],
        allowed_methods=["POST", "GET"],
    )

    adapter = HTTPAdapter(
        pool_connections=pool_size,
        pool_maxsize=pool_size,
        pool_block=pool_block,
        max_retries=retry_strategy,
    )

    session.mount("https://", adapter)
    session.mount("http://", adapter)

    return session


# ─── Pre-built sessions for each external service ───

gpt_session = _create_session(GPT_POOL_SIZE)
tts_session = _create_session(TTS_POOL_SIZE)
mistral_session = _create_session(MISTRAL_POOL_SIZE)
transcript_session = _create_session(TRANSCRIPT_POOL_SIZE)
cloudinary_session = _create_session(CLOUDINARY_POOL_SIZE)
icons8_session = _create_session(10)
board_processor_session = _create_session(BOARD_PROCESSOR_POOL_SIZE)

print("✅ HTTP Connection Pools initialized:")
print(f"   GPT:             {GPT_POOL_SIZE} connections")
print(f"   TTS:             {TTS_POOL_SIZE} connections")
print(f"   Mistral:         {MISTRAL_POOL_SIZE} connections")
print(f"   Transcript:      {TRANSCRIPT_POOL_SIZE} connections")
print(f"   Cloudinary:      {CLOUDINARY_POOL_SIZE} connections")
print(f"   Board Processor: {BOARD_PROCESSOR_POOL_SIZE} connections")