"""
Tests for configuration system.
"""

import pytest
import tempfile
import os
from pathlib import Path

from src.core.config import Config, BackendConfig, ConfigLoader, get_config, reload_config


class TestConfigLoader:
    """Test configuration loading."""
    
    def test_load_default_config(self):
        """Test loading with no config files (uses defaults)."""
        config = ConfigLoader.load(
            config_path=Path("nonexistent.yaml"),
            env_file=Path("nonexistent.env")
        )
        
        assert isinstance(config, Config)
        assert config.active_backend == "wan_t2v_14b"
        assert len(config.backends) == 0  # No YAML loaded
    
    def test_load_yaml_config(self):
        """Test loading from YAML file."""
        yaml_content = """
backends:
  test_backend:
    name: "Test Backend"
    class: "test.TestBackend"
    model_id: "test/model"
    vram_gb: 8
    dtype: "fp16"
    enable_vae_slicing: true
    enable_vae_tiling: false
    chunking:
      enabled: true
      mode: "sequential"
      max_chunk_seconds: 4
      overlap_seconds: 1

active_backend: "test_backend"
defaults:
  fps: 30
checkpoint_db: "test.db"
model_cache_dir: "~/test_cache"
"""
        
        with tempfile.NamedTemporaryFile(mode='w', suffix='.yaml', delete=False) as f:
            f.write(yaml_content)
            yaml_path = f.name
        
        try:
            config = ConfigLoader.load(config_path=Path(yaml_path))
            
            assert config.active_backend == "test_backend"
            assert "test_backend" in config.backends
            
            backend = config.get_backend("test_backend")
            assert backend.name == "Test Backend"
            assert backend.vram_gb == 8
            assert backend.chunking_mode == "sequential"
            assert config.defaults["fps"] == 30
        finally:
            os.unlink(yaml_path)
    
    def test_load_env_file(self, monkeypatch):
        """Test loading from .env file."""
        # Clear any existing env vars first
        for key in ['ACTIVE_BACKEND', 'MODEL_CACHE_DIR', 'LOG_LEVEL']:
            monkeypatch.delenv(key, raising=False)
        
        env_content = """
ACTIVE_BACKEND=env_backend
MODEL_CACHE_DIR=/env/cache
LOG_LEVEL=DEBUG
"""
        
        with tempfile.NamedTemporaryFile(mode='w', suffix='.env', delete=False) as f:
            f.write(env_content)
            env_path = f.name
        
        try:
            config = ConfigLoader.load(
                config_path=Path("nonexistent.yaml"),
                env_file=Path(env_path)
            )
            
            assert config.active_backend == "env_backend"
            assert "/env/cache" in config.model_cache_dir or "\\env\\cache" in config.model_cache_dir
            assert config.log_level == "DEBUG"
        finally:
            os.unlink(env_path)
            # Clean up env vars
            for key in ['ACTIVE_BACKEND', 'MODEL_CACHE_DIR', 'LOG_LEVEL']:
                monkeypatch.delenv(key, raising=False)
    
    def test_env_variable_override(self, monkeypatch):
        """Test that environment variables override config files."""
        # Clear env var first
        monkeypatch.delenv("ACTIVE_BACKEND", raising=False)
        
        yaml_content = """
active_backend: yaml_backend
model_cache_dir: ~/yaml_cache
"""
        
        with tempfile.NamedTemporaryFile(mode='w', suffix='.yaml', delete=False) as f:
            f.write(yaml_content)
            yaml_path = f.name
        
        try:
            monkeypatch.setenv("ACTIVE_BACKEND", "env_override")
            
            config = ConfigLoader.load(config_path=Path(yaml_path))
            
            # Environment variable should override
            assert config.active_backend == "env_override"
            # But other settings from YAML should remain
            assert "yaml_cache" in config.model_cache_dir
        finally:
            os.unlink(yaml_path)
            monkeypatch.delenv("ACTIVE_BACKEND", raising=False)
    
    def test_path_expansion(self):
        """Test that paths are properly expanded."""
        config = ConfigLoader.load(
            config_path=Path("nonexistent.yaml"),
            env_file=Path("nonexistent.env")
        )
        
        # Default paths should be expanded
        assert not config.model_cache_dir.startswith("~")
        assert not config.checkpoint_db.startswith("~")
    
    def test_get_backend_not_found(self):
        """Test getting a non-existent backend."""
        config = Config()
        
        with pytest.raises(ValueError, match="not found"):
            config.get_backend("nonexistent")


class TestBackendConfig:
    """Test backend configuration."""
    
    def test_backend_config_defaults(self):
        """Test backend config with defaults."""
        config = BackendConfig(
            name="Test",
            model_class="test.Test",
            model_id="test/model",
            vram_gb=12,
            dtype="fp16"
        )
        
        assert config.enable_vae_slicing is True
        assert config.enable_vae_tiling is False
        assert config.chunking_enabled is True
        assert config.chunking_mode == "sequential"