import os
import sys
import tomllib
from dataclasses import dataclass, field
from pathlib import Path

from dotenv import load_dotenv


@dataclass
class HotkeyCfg:
    capture: str = "<ctrl>+<shift>+a"
    toggle: str = "<ctrl>+<shift>+h"


@dataclass
class OverlayCfg:
    width: int = 460
    height: int = 360
    margin_right: int = 20
    margin_bottom: int = 40
    alpha: float = 0.93
    font_size: int = 13
    font_family: str = "Courier"
    bg_color: str = "#0f0f1a"
    fg_color: str = "#e2e2e2"
    accent_color: str = "#4ade80"


@dataclass
class ScreenshotCfg:
    delay_ms: int = 200
    tmp_path: str = "/tmp/support_agent_screenshot.png"


@dataclass
class AICfg:
    api_key: str = ""
    base_url: str = ""
    model: str = "gpt-4o"
    max_tokens: int = 1500
    system_prompt: str = "你是一个答题助手，请分析截图中的题目，给出答案和解析。"


@dataclass
class Config:
    hotkeys: HotkeyCfg = field(default_factory=HotkeyCfg)
    overlay: OverlayCfg = field(default_factory=OverlayCfg)
    screenshot: ScreenshotCfg = field(default_factory=ScreenshotCfg)
    ai: AICfg = field(default_factory=AICfg)


def _find_config_toml() -> Path | None:
    candidates = [
        Path.cwd() / "config.toml",
        Path(__file__).parent.parent / "config.toml",
        Path.home() / ".config" / "support-agent" / "config.toml",
    ]
    for p in candidates:
        if p.exists():
            return p
    return None


def load_config() -> Config:
    load_dotenv()

    cfg = Config()

    toml_path = _find_config_toml()
    if toml_path:
        with open(toml_path, "rb") as f:
            data = tomllib.load(f)

        if "hotkeys" in data:
            h = data["hotkeys"]
            cfg.hotkeys.capture = h.get("capture", cfg.hotkeys.capture)
            cfg.hotkeys.toggle = h.get("toggle", cfg.hotkeys.toggle)

        if "overlay" in data:
            o = data["overlay"]
            cfg.overlay.width = o.get("width", cfg.overlay.width)
            cfg.overlay.height = o.get("height", cfg.overlay.height)
            cfg.overlay.margin_right = o.get("margin_right", cfg.overlay.margin_right)
            cfg.overlay.margin_bottom = o.get("margin_bottom", cfg.overlay.margin_bottom)
            cfg.overlay.alpha = o.get("alpha", cfg.overlay.alpha)
            cfg.overlay.font_size = o.get("font_size", cfg.overlay.font_size)
            cfg.overlay.font_family = o.get("font_family", cfg.overlay.font_family)
            cfg.overlay.bg_color = o.get("bg_color", cfg.overlay.bg_color)
            cfg.overlay.fg_color = o.get("fg_color", cfg.overlay.fg_color)
            cfg.overlay.accent_color = o.get("accent_color", cfg.overlay.accent_color)

        if "screenshot" in data:
            s = data["screenshot"]
            cfg.screenshot.delay_ms = s.get("delay_ms", cfg.screenshot.delay_ms)
            cfg.screenshot.tmp_path = s.get("tmp_path", cfg.screenshot.tmp_path)

        if "ai" in data:
            a = data["ai"]
            cfg.ai.base_url = a.get("base_url", cfg.ai.base_url)
            cfg.ai.model = a.get("model", cfg.ai.model)
            cfg.ai.max_tokens = a.get("max_tokens", cfg.ai.max_tokens)
            cfg.ai.system_prompt = a.get("system_prompt", cfg.ai.system_prompt)

    # 环境变量优先级高于 config.toml
    cfg.ai.api_key = os.environ.get("OPENAI_API_KEY", "")
    env_base_url = os.environ.get("OPENAI_BASE_URL", "")
    if env_base_url:
        cfg.ai.base_url = env_base_url

    if not cfg.ai.api_key:
        print("警告：未设置 OPENAI_API_KEY，请在 .env 文件中配置", file=sys.stderr)

    return cfg