#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""Environment config helpers with light validation and normalization."""

import os
import warnings
from dataclasses import dataclass
from typing import Optional

FALSEY_ENV_VALUES = {"0", "false", "no", "off"}
PROVIDER_ALIASES = {
    "openai_compatible": "OPENAI",
    "openai_compat": "OPENAI",
    "claude": "ANTHROPIC",
    "google": "GEMINI",
    "vertex": "GEMINI",
    "vertexai": "GEMINI",
}

# Default dev CORS origins (localhost variants used by common dev servers)
_LOCALHOST_ORIGINS = [
    "http://localhost:5173",
    "http://localhost:3000",
    "http://localhost:8000",
    "http://127.0.0.1:5173",
    "http://127.0.0.1:3000",
    "http://127.0.0.1:8000",
]


def get_cors_origins() -> list[str]:
    """Get CORS allowed origins from environment.

    Reads CORS_ALLOWED_ORIGINS env var (comma-separated).
    Falls back to localhost dev origins if not set.
    Warns if "*" is configured (only acceptable for local dev).
    """
    origins = get_env_list("CORS_ALLOWED_ORIGINS", default=[])
    if origins:
        if "*" in origins:
            warnings.warn(
                "CORS_ALLOWED_ORIGINS contains '*' — this allows any origin. "
                "Only use in local development, never in production.",
                UserWarning,
            )
        return origins
    # Fallback: local dev only
    return _LOCALHOST_ORIGINS


@dataclass(frozen=True)
class AgentModelConfig:
    """Resolved model config for one agent."""

    model_name: str
    provider: str


def _get_env_raw(key: str) -> Optional[str]:
    value = os.getenv(key)
    if value is None:
        return None
    value = value.strip()
    return value or None


def get_env_str(key: str, default: str = "") -> str:
    """Get trimmed string from env."""
    value = _get_env_raw(key)
    return value if value is not None else default


def get_env_list(key: str, default: list = None) -> list:
    """Get comma-separated list from env."""
    value = _get_env_raw(key)
    if not value:
        return default or []
    return [item.strip() for item in value.split(",") if item.strip()]


def get_env_float(key: str, default: float = 0.0) -> float:
    """Get float from env."""
    value = _get_env_raw(key)
    if value is None:
        return default
    try:
        return float(value)
    except ValueError:
        return default


def get_env_int(key: str, default: int = 0) -> int:
    """Get int from env."""
    value = _get_env_raw(key)
    if value is None:
        return default
    try:
        return int(value)
    except ValueError:
        return default


def get_env_bool(key: str, default: bool = False) -> bool:
    """Parse common truthy/falsey env values."""
    value = _get_env_raw(key)
    if value is None:
        return default
    return value.lower() not in FALSEY_ENV_VALUES


def canonicalize_model_provider(provider: Optional[str]) -> str:
    """Normalize provider labels to stable uppercase names."""
    if not provider:
        return "OPENAI"
    normalized = provider.strip().lower().replace("-", "_")
    normalized = PROVIDER_ALIASES.get(normalized, normalized)
    return normalized.upper()


def get_agent_model_config(agent_id: str) -> AgentModelConfig:
    """Resolve model config with agent-specific override and global fallback."""
    agent_key = agent_id.upper().replace("-", "_")
    model_name = get_env_str(f"AGENT_{agent_key}_MODEL_NAME")
    provider = get_env_str(f"AGENT_{agent_key}_MODEL_PROVIDER")

    if not model_name:
        model_name = get_env_str("MODEL_NAME", "gpt-4o")
    if not provider:
        provider = get_env_str("MODEL_PROVIDER", "OPENAI")

    return AgentModelConfig(
        model_name=model_name,
        provider=canonicalize_model_provider(provider),
    )