// src/main/win-state.ts
import { app, screen, BrowserWindow } from 'electron'
import { join } from 'path'
import { readFileSync, writeFile } from 'fs'

interface WinState {
  x: number | null
  y: number | null
  width: number
  height: number
  maximized: boolean
}

const STATE_FILE = join(app.getPath('userData'), 'jrdm-win-state.json')
const MIN_WIDTH = 900
const MIN_HEIGHT = 600
const DEFAULT_WIDTH = 1200
const DEFAULT_HEIGHT = 800

function parseJson(str: string): WinState | null {
  try { return JSON.parse(str) }
  catch { return null }
}

function getLastState(): WinState {
  try {
    const raw = readFileSync(STATE_FILE, 'utf-8')
    const state = parseJson(raw)
    if (state) {
      const display = screen.getPrimaryDisplay().workArea
      if (state.x != null && (state.x < 0 || state.x > display.width - 100)) {
        state.x = null; state.y = null
      }
      if (state.y != null && (state.y < 0 || state.y > display.height - 100)) {
        state.x = null; state.y = null
      }
      state.width = Math.max(state.width || DEFAULT_WIDTH, MIN_WIDTH)
      state.height = Math.max(state.height || DEFAULT_HEIGHT, MIN_HEIGHT)
      return state
    }
  } catch { /* file doesn't exist yet */ }
  return { x: null, y: null, width: DEFAULT_WIDTH, height: DEFAULT_HEIGHT, maximized: false }
}

function saveState(win: BrowserWindow): void {
  const bounds = win.getBounds()
  const state = { ...bounds, maximized: win.isMaximized() }
  writeFile(STATE_FILE, JSON.stringify(state), 'utf-8', () => {})
}

export function restoreAndTrack(win: BrowserWindow): void {
  const lastState = getLastState()
  if (lastState.x != null && lastState.y != null) {
    win.setBounds({ x: lastState.x, y: lastState.y, width: lastState.width, height: lastState.height })
  }
  if (lastState.maximized) {
    win.maximize()
  }
  win.on('close', () => saveState(win))
}