package config

import (
	"os"

	"gopkg.in/yaml.v3"
)

// DisplayConfig configures the independent kiosk canvas process.
type DisplayConfig struct {
	Enabled    bool   `yaml:"enabled"`
	Command    string `yaml:"command"`
	User       string `yaml:"user"`
	Display    string `yaml:"display"`
	Xauthority string `yaml:"xauthority"`
}

type Config struct {
	Display DisplayConfig `yaml:"display"`
	Serial  struct {
		Path string `yaml:"path"`
	} `yaml:"serial"`
	Video struct {
		Enabled   bool   `yaml:"enabled"`
		AuxIndex  int    `yaml:"aux_index"`
		Threshold int16  `yaml:"threshold"`
		Command   string `yaml:"command"`
	} `yaml:"video"`
	Logging struct {
		Enabled bool   `yaml:"enabled"`
		Path    string `yaml:"path"`
	} `yaml:"logging"`
}

func Default() Config {
	var c Config
	c.Display = DefaultDisplay()
	c.Serial.Path = "/dev/ttyS0"
	c.Video.Enabled = true
	c.Video.AuxIndex = 5 // AUX2, zero-based
	c.Video.Threshold = -512
	c.Video.Command = "fpv-video"
	c.Logging.Enabled = true
	return c
}

// DefaultDisplay starts the kiosk canvas before video on the desktop X
// server owned by the unprivileged display user.
func DefaultDisplay() DisplayConfig {
	return DisplayConfig{
		Enabled:    true,
		Command:    "/usr/local/bin/groundstation-display",
		User:       "orangepi",
		Display:    ":0",
		Xauthority: "/home/orangepi/.Xauthority",
	}
}

func Load(path string) (Config, error) {
	config := Default()
	data, err := os.ReadFile(path)
	if err != nil {
		if os.IsNotExist(err) {
			return config, nil
		}
		return config, err
	}
	if err := yaml.Unmarshal(data, &config); err != nil {
		return config, err
	}
	return config, nil
}