package main

import (
	"encoding/json"
	"os"
	"path/filepath"

	"fyne.io/fyne/v2"
)

const (
	DefaultWindowWidth  = 800.0
	DefaultWindowHeight = 600.0

	ConfigFileName = "secure-editor-go-config.json"
)

// windowConfig is persisted to ~/.cache/secure-editor-go-config.json so the
// editor remembers its window size across runs.
type windowConfig struct {
	Width  float32 `json:"width"`
	Height float32 `json:"height"`
}

func configPath() (string, error) {
	home, err := os.UserHomeDir()
	if err != nil {
		return "", err
	}
	return filepath.Join(home, ".cache", ConfigFileName), nil
}

func defaultConfig() windowConfig {
	return windowConfig{Width: DefaultWindowWidth, Height: DefaultWindowHeight}
}

func loadConfig() windowConfig {
	p, err := configPath()
	if err != nil {
		return defaultConfig()
	}
	data, err := os.ReadFile(p)
	if err != nil {
		return defaultConfig()
	}
	var c windowConfig
	if err := json.Unmarshal(data, &c); err != nil {
		return defaultConfig()
	}
	if c.Width <= 0 || c.Height <= 0 {
		return defaultConfig()
	}
	return c
}

func saveConfig(size fyne.Size) {
	p, err := configPath()
	if err != nil {
		return
	}
	if err := os.MkdirAll(filepath.Dir(p), 0755); err != nil {
		return
	}
	c := windowConfig{Width: size.Width, Height: size.Height}
	data, err := json.MarshalIndent(c, "", "  ")
	if err != nil {
		return
	}
	_ = os.WriteFile(p, data, 0644)
}

// clampToScreen shrinks size so it never exceeds the visible desktop area.
// When the desktop size can't be determined it returns size unchanged.
func clampToScreen(size fyne.Size) fyne.Size {
	sw, sh := desktopSize()
	if sw <= 0 || sh <= 0 {
		return size
	}
	w, h := size.Width, size.Height
	if w > sw {
		w = sw
	}
	if h > sh {
		h = sh
	}
	return fyne.NewSize(w, h)
}