"""Configuration management for CAD-Documenter."""

import os
from pathlib import Path
from dataclasses import dataclass, field
from typing import Literal

try:
    import tomllib
except ImportError:
    import tomli as tomllib


@dataclass
class FrameExtractionConfig:
    """Frame extraction configuration."""
    mode: Literal["interval", "scene", "hybrid"] = "hybrid"
    interval_seconds: float = 2.0
    scene_threshold: float = 0.3
    min_frames: int = 5
    max_frames: int = 15
    blur_threshold: float = 100.0  # Laplacian variance threshold


@dataclass
class TranscriptionConfig:
    """Transcription configuration."""
    model: str = "base"  # tiny, base, small, medium, large
    language: str | None = None  # None = auto-detect


@dataclass
class APIConfig:
    """API configuration."""
    provider: Literal["openai", "anthropic"] = "openai"
    api_key: str | None = None
    vision_model: str | None = None  # None = use provider default
    text_model: str | None = None


@dataclass
class ProcessingConfig:
    """Video/audio processing configuration."""
    whisper_model: str = "base"
    frame_interval: float = 2.0
    use_scene_detection: bool = True
    max_frames: int = 15
    scene_threshold: float = 0.3


@dataclass
class OutputConfig:
    """Output configuration."""
    include_bom: bool = True
    include_atomizer_hints: bool = True
    include_raw_transcript: bool = True
    include_frames: bool = True
    pdf_template: str = "default"


@dataclass
class Config:
    """Main configuration."""
    api: APIConfig = field(default_factory=APIConfig)
    processing: ProcessingConfig = field(default_factory=ProcessingConfig)
    output: OutputConfig = field(default_factory=OutputConfig)


def load_config(config_path: Path | None = None) -> Config:
    """
    Load configuration from file and environment variables.
    
    Priority (highest to lowest):
    1. Environment variables
    2. Config file
    3. Defaults
    """
    config = Config()
    
    # Try to load config file
    if config_path is None:
        # Check common locations
        locations = [
            Path.cwd() / "cad-documenter.toml",
            Path.cwd() / ".cad-documenter.toml",
            Path.home() / ".cad-documenter.toml",
            Path.home() / ".config" / "cad-documenter" / "config.toml",
        ]
        for loc in locations:
            if loc.exists():
                config_path = loc
                break
    
    if config_path and config_path.exists():
        with open(config_path, "rb") as f:
            data = tomllib.load(f)
        
        # API config
        if "api" in data:
            api_data = data["api"]
            config.api.provider = api_data.get("provider", config.api.provider)
            config.api.api_key = api_data.get("api_key", config.api.api_key)
            config.api.vision_model = api_data.get("vision_model", config.api.vision_model)
            config.api.text_model = api_data.get("text_model", config.api.text_model)
        
        # Processing config
        if "processing" in data:
            proc_data = data["processing"]
            config.processing.whisper_model = proc_data.get("whisper_model", config.processing.whisper_model)
            config.processing.frame_interval = proc_data.get("frame_interval", config.processing.frame_interval)
            config.processing.use_scene_detection = proc_data.get("use_scene_detection", config.processing.use_scene_detection)
            config.processing.max_frames = proc_data.get("max_frames", config.processing.max_frames)
            config.processing.scene_threshold = proc_data.get("scene_threshold", config.processing.scene_threshold)
        
        # Output config
        if "output" in data:
            out_data = data["output"]
            config.output.include_bom = out_data.get("include_bom", config.output.include_bom)
            config.output.include_atomizer_hints = out_data.get("include_atomizer_hints", config.output.include_atomizer_hints)
            config.output.include_raw_transcript = out_data.get("include_raw_transcript", config.output.include_raw_transcript)
            config.output.include_frames = out_data.get("include_frames", config.output.include_frames)
            config.output.pdf_template = out_data.get("pdf_template", config.output.pdf_template)
    
    # Override with environment variables
    if os.environ.get("CAD_DOC_PROVIDER"):
        config.api.provider = os.environ["CAD_DOC_PROVIDER"]
    
    if os.environ.get("OPENAI_API_KEY"):
        if config.api.provider == "openai" and not config.api.api_key:
            config.api.api_key = os.environ["OPENAI_API_KEY"]
    
    if os.environ.get("ANTHROPIC_API_KEY"):
        if config.api.provider == "anthropic" and not config.api.api_key:
            config.api.api_key = os.environ["ANTHROPIC_API_KEY"]
    
    if os.environ.get("CAD_DOC_WHISPER_MODEL"):
        config.processing.whisper_model = os.environ["CAD_DOC_WHISPER_MODEL"]
    
    return config


def create_default_config(path: Path) -> None:
    """Create a default config file."""
    content = '''# CAD-Documenter Configuration

[api]
# Vision API provider: "openai" or "anthropic"
provider = "openai"

# API key (or set OPENAI_API_KEY / ANTHROPIC_API_KEY environment variable)
# api_key = "sk-..."

# Model overrides (optional - uses provider defaults if not set)
# vision_model = "gpt-4o"
# text_model = "gpt-4o-mini"

[processing]
# Whisper model for transcription: tiny, base, small, medium, large
whisper_model = "base"

# Seconds between frame extractions (if not using scene detection)
frame_interval = 2.0

# Use scene change detection for smarter frame selection
use_scene_detection = true

# Maximum frames to send to vision API
max_frames = 15

# Scene detection sensitivity (0.0-1.0, lower = more sensitive)
scene_threshold = 0.3

[output]
# Include Bill of Materials in documentation
include_bom = true

# Include Atomizer FEA hints
include_atomizer_hints = true

# Include raw transcript at end of documentation
include_raw_transcript = true

# Include extracted frames in output directory
include_frames = true

# PDF template name (for --pdf option)
pdf_template = "default"
'''
    path.parent.mkdir(parents=True, exist_ok=True)
    path.write_text(content)