import { powerMonitor, BrowserWindow } from 'electron'
import { IPC } from '@shared/ipc'
import type { Tick } from '@shared/types'
import { isQuietAt } from '@shared/types'
import { getExercises, getSettings, updateExercise } from './store'
import { fireReminder } from './notifications'

const TICK_MS = 1000
const CHECK_MS = 5000
let tickHandle: NodeJS.Timeout | null = null
let lastCheckAt = 0
let paused = false

function checkDueExercises(): void {
  if (paused) return
  const settings = getSettings()
  if (!settings.globalEnabled) return

  // Inside the quiet window: defer all due fires to the next minute boundary.
  // The next tick after the window closes will pick them up.
  if (isQuietAt(settings.quietHours, new Date())) return

  const now = Date.now()
  const exercises = getExercises()
  for (const ex of exercises) {
    if (!ex.enabled) continue
    if (ex.nextFireAt <= now) {
      const updated = updateExercise(ex.id, {
        nextFireAt: now + ex.intervalMinutes * 60_000
      })
      if (updated) fireReminder(updated, settings.notificationMode)
    }
  }
}

function broadcastTicks(): void {
  const now = Date.now()
  const ticks: Tick[] = getExercises().map((e) => ({
    exerciseId: e.id,
    msUntilFire: Math.max(0, e.nextFireAt - now),
    enabled: e.enabled
  }))
  for (const win of BrowserWindow.getAllWindows()) {
    if (!win.isDestroyed()) win.webContents.send(IPC.evtTick, ticks)
  }
}

function tick(): void {
  broadcastTicks()
  const now = Date.now()
  if (now - lastCheckAt >= CHECK_MS) {
    lastCheckAt = now
    checkDueExercises()
  }
}

export function startScheduler(): void {
  if (tickHandle) return
  lastCheckAt = 0
  tickHandle = setInterval(tick, TICK_MS)
  // Run an immediate tick so renderer hydrates quickly.
  tick()

  powerMonitor.on('resume', () => {
    lastCheckAt = 0
    tick()
  })
  powerMonitor.on('unlock-screen', () => {
    lastCheckAt = 0
    tick()
  })
}

export function stopScheduler(): void {
  if (tickHandle) {
    clearInterval(tickHandle)
    tickHandle = null
  }
}

export function setPaused(value: boolean): void {
  paused = value
}

export function isPaused(): boolean {
  return paused
}

export function forceCheck(): void {
  lastCheckAt = 0
  tick()
}