"""Core configuration management."""

from __future__ import annotations

from pathlib import Path

from pydantic import Field
from pydantic_settings import BaseSettings


class MCPConfig(BaseSettings):
    """MCP server configuration."""

    model_config = {"env_prefix": "MCP_", "env_file": ".env", "extra": "ignore"}

    host: str = "0.0.0.0"
    port: int = 3100
    log_level: str = "info"
    max_connections: int = 100
    tool_timeout: float = 30.0


class DatabaseConfig(BaseSettings):
    """Database configuration.

    Environment variable prefix: DB_
    All fields map to DB_* env vars (e.g. DB_POSTGRES_URL).
    """

    model_config = {"env_prefix": "DB_", "env_file": ".env", "extra": "ignore"}

    postgres_url: str = ""
    postgres_sync_url: str = ""
    redis_url: str = ""
    qdrant_url: str = ""
    qdrant_collection: str = "hermes_memory"

    # Async connection pool settings
    pool_size: int = 5
    max_overflow: int = 10
    pool_timeout: int = 30
    pool_recycle: int = 1800
    pool_pre_ping: bool = True
    echo_sql: bool = False


class ModelConfig(BaseSettings):
    """LLM model configuration."""

    model_config = {"env_prefix": "MODEL_", "env_file": ".env", "extra": "ignore"}

    provider: str = "openai"
    name: str = "gpt-4o"
    api_key: str = ""
    base_url: str = ""
    temperature: float = 0.1
    max_tokens: int = 4096
    embedding_model: str = "BAAI/bge-small-en-v1.5"
    embedding_dimension: int = 384

    openrouter_api_key: str = ""
    openrouter_base_url: str = "https://openrouter.ai/api/v1"
    openrouter_site_url: str = "https://github.com/mysterious75/VGTC"
    openrouter_app_name: str = "VGTC Platform"


class ObservabilityConfig(BaseSettings):
    """Observability configuration."""

    model_config = {"env_prefix": "OBS_", "env_file": ".env", "extra": "ignore"}

    enabled: bool = True
    langsmith_api_key: str = ""
    langsmith_project: str = "hermes-platform"
    langsmith_endpoint: str = "https://api.smith.langchain.com"
    otel_endpoint: str = "http://localhost:4317"
    otel_service_name: str = "hermes-platform"
    trace_prompts: bool = True
    trace_tool_calls: bool = True


class WorkflowConfig(BaseSettings):
    """Workflow engine configuration."""

    model_config = {"env_prefix": "WORKFLOW_", "env_file": ".env", "extra": "ignore"}

    engine: str = "temporal"
    temporal_host: str = "localhost:7233"
    temporal_namespace: str = "default"
    checkpoint_interval: int = 300
    max_retries: int = 3
    timeout_seconds: int = 3600
    airflow_username: str = ""
    airflow_password: str = ""


class SecurityConfig(BaseSettings):
    """Security configuration."""

    model_config = {"env_prefix": "SECURITY_", "env_file": ".env", "extra": "ignore"}

    secret_key: str = ""
    algorithm: str = "HS256"
    access_token_expire_minutes: int = 30
    allowed_origins: list[str] = ["http://localhost:3000"]
    api_key: str = ""
    enable_auth: bool = True
    rate_limit_per_minute: int = 60


class ResearchConfig(BaseSettings):
    """Research agent configuration."""

    model_config = {"env_prefix": "RESEARCH_", "env_file": ".env", "extra": "ignore"}

    max_search_results: int = 10
    max_repos_to_analyze: int = 5
    report_max_tokens: int = 8192
    analysis_depth: str = "thorough"
    brave_api_key: str = ""


class Settings(BaseSettings):
    """Main application settings."""

    model_config = {"env_prefix": "HERMES_", "env_file": ".env", "extra": "ignore"}

    app_name: str = "Hermes Platform"
    debug: bool = False
    environment: str = "development"
    log_level: str = "INFO"
    base_dir: Path = Field(default_factory=lambda: Path(__file__).parent.parent.parent)

    mcp: MCPConfig = Field(default_factory=MCPConfig)
    database: DatabaseConfig = Field(default_factory=DatabaseConfig)
    model: ModelConfig = Field(default_factory=ModelConfig)
    observability: ObservabilityConfig = Field(default_factory=ObservabilityConfig)
    workflow: WorkflowConfig = Field(default_factory=WorkflowConfig)
    security: SecurityConfig = Field(default_factory=SecurityConfig)
    research: ResearchConfig = Field(default_factory=ResearchConfig)


_settings: Settings | None = None


def get_settings() -> Settings:
    """Get singleton settings instance."""
    global _settings
    if _settings is None:
        _settings = Settings()
    return _settings


def reset_settings() -> None:
    """Reset settings (useful for testing)."""
    global _settings
    _settings = None