"""Factory for creating orchestrators.

Implements the Factory Pattern (GoF) for creating the appropriate
orchestrator based on configuration and available credentials.

Design Principles:
- Open/Closed: Easy to add new orchestrator types without modifying existing code
- Dependency Inversion: Returns protocol-compatible objects, not concrete types
- Single Responsibility: Only handles orchestrator creation logic
"""

from typing import TYPE_CHECKING, Literal

import structlog

from src.orchestrators.base import (
    JudgeHandlerProtocol,
    OrchestratorProtocol,
    SearchHandlerProtocol,
)
from src.orchestrators.simple import Orchestrator
from src.utils.config import settings
from src.utils.models import OrchestratorConfig

if TYPE_CHECKING:
    from src.orchestrators.advanced import AdvancedOrchestrator

logger = structlog.get_logger()


def _get_advanced_orchestrator_class() -> type["AdvancedOrchestrator"]:
    """Import AdvancedOrchestrator lazily to avoid hard dependency.

    This allows the simple mode to work without agent-framework-core installed.

    Returns:
        The AdvancedOrchestrator class

    Raises:
        ValueError: If agent-framework-core is not installed
    """
    try:
        from src.orchestrators.advanced import AdvancedOrchestrator

        return AdvancedOrchestrator
    except ImportError as e:
        logger.error("Failed to import AdvancedOrchestrator", error=str(e))
        raise ValueError(
            "Advanced mode requires agent-framework-core. "
            "Install with: pip install agent-framework-core. "
            "Or use mode='simple' instead."
        ) from e


def create_orchestrator(
    search_handler: SearchHandlerProtocol | None = None,
    judge_handler: JudgeHandlerProtocol | None = None,
    config: OrchestratorConfig | None = None,
    mode: Literal["simple", "magentic", "advanced", "hierarchical"] | None = None,
    api_key: str | None = None,
) -> OrchestratorProtocol:
    """
    Create an orchestrator instance.

    This factory automatically selects the appropriate orchestrator based on:
    1. Explicit mode parameter (if provided)
    2. Available API keys (auto-detection)

    Args:
        search_handler: The search handler (required for simple mode)
        judge_handler: The judge handler (required for simple mode)
        config: Optional configuration (max_iterations, timeouts, etc.)
        mode: "simple", "magentic", "advanced", or "hierarchical"
              Note: "magentic" is an alias for "advanced" (kept for backwards compatibility)
        api_key: Optional API key for advanced mode (OpenAI)

    Returns:
        Orchestrator instance implementing OrchestratorProtocol

    Raises:
        ValueError: If required handlers are missing for simple mode
        ValueError: If advanced mode is requested but dependencies are missing
    """
    effective_config = config or OrchestratorConfig()
    effective_mode = _determine_mode(mode, api_key)
    logger.info("Creating orchestrator", mode=effective_mode)

    if effective_mode == "advanced":
        orchestrator_cls = _get_advanced_orchestrator_class()
        return orchestrator_cls(
            max_rounds=effective_config.max_iterations,
            api_key=api_key,
        )

    if effective_mode == "hierarchical":
        from src.orchestrators.hierarchical import HierarchicalOrchestrator

        return HierarchicalOrchestrator(config=effective_config)

    # Simple mode requires handlers
    if search_handler is None or judge_handler is None:
        raise ValueError("Simple mode requires search_handler and judge_handler")

    return Orchestrator(
        search_handler=search_handler,
        judge_handler=judge_handler,
        config=effective_config,
    )


def _determine_mode(explicit_mode: str | None, api_key: str | None) -> str:
    """Determine which mode to use.

    Priority:
    1. Explicit mode parameter
    2. Auto-detect based on available API keys

    Args:
        explicit_mode: Mode explicitly requested by caller
        api_key: API key provided by caller

    Returns:
        Effective mode string: "simple", "advanced", or "hierarchical"
    """
    if explicit_mode:
        if explicit_mode in ("magentic", "advanced"):
            return "advanced"
        if explicit_mode == "hierarchical":
            return "hierarchical"
        return "simple"

    # Auto-detect: advanced if paid API key available
    if settings.has_openai_key or (api_key and api_key.startswith("sk-")):
        return "advanced"

    return "simple"