"""Unified optional external-model call; no changes to HF inference routing."""
import os
import time
from .agent_prompts import build_agent_messages, prompt_sha256, PROMPT_VERSION
from .llm_usage import usage_summary

def generate(messages, *, provider='azure', model=None, max_completion_tokens=1200):
    if os.getenv("ENABLE_EXTERNAL_LLM", "false").lower() not in {"1", "true", "yes"}:
        raise RuntimeError("External LLM calls are disabled (ENABLE_EXTERNAL_LLM=false)")
    if provider == "azure":
        from .providers.azure import complete
    elif provider == "deepseek":
        from .providers.deepseek import complete
    else:
        raise ValueError(f"Unsupported provider: {provider}")
    started = time.monotonic()
    result = complete(messages, model=model, max_completion_tokens=max_completion_tokens)
    result['elapsed_s'] = round(time.monotonic() - started, 3)
    result['metering'] = usage_summary(result)
    return result

def run_application(*, application, context, question, provider='azure', model=None, max_completion_tokens=1200):
    messages = build_agent_messages(application, context, question)
    result = generate(messages, provider=provider, model=model, max_completion_tokens=max_completion_tokens)
    result['application'] = application
    result['prompt_version'] = PROMPT_VERSION
    result['prompt_sha256'] = prompt_sha256(messages)
    return result