config.py

import os
import yaml
from dataclasses import dataclass, field
from pathlib import Path


@dataclass
class VisionConfig:
    base_url: str = "https://api.openai.com/v1"
    api_key: str = ""
    model: str = "gpt-4o"
    max_tokens: int = 512
    image_max_size: int = 1920
    timeout: float = 600.0


@dataclass
class PromptsConfig:
    system: str = (
        "You are an expert photo metadata specialist. Analyze images carefully "
        "and return accurate, descriptive tags and captions. Always respond with valid JSON only."
    )
    user: str = (
        'Analyze this image and return a JSON object with exactly two fields: '
        '"tags" (array of concise keyword strings) and "caption" (one sentence description).'
    )


@dataclass
class ServerConfig:
    host: str = "0.0.0.0"
    port: int = 8000


@dataclass
class Config:
    vision: VisionConfig = field(default_factory=VisionConfig)
    prompts: PromptsConfig = field(default_factory=PromptsConfig)
    server: ServerConfig = field(default_factory=ServerConfig)


def load_config(path: str = "config.yaml") -> Config:
    cfg = Config()

    if Path(path).exists():
        with open(path) as f:
            data = yaml.safe_load(f) or {}

        if v := data.get("vision"):
            cfg.vision = VisionConfig(**{k: val for k, val in v.items() if hasattr(VisionConfig, k)})

        if p := data.get("prompts"):
            cfg.prompts = PromptsConfig(**{k: val for k, val in p.items() if hasattr(PromptsConfig, k)})

        if s := data.get("server"):
            cfg.server = ServerConfig(**{k: val for k, val in s.items() if hasattr(ServerConfig, k)})

    # Environment variable overrides (useful for secrets)
    if key := os.environ.get("VISION_API_KEY"):
        cfg.vision.api_key = key
    if url := os.environ.get("VISION_BASE_URL"):
        cfg.vision.base_url = url
    if model := os.environ.get("VISION_MODEL"):
        cfg.vision.model = model

    return cfg