import { loadState, saveState, sumMonthUsages, projectedMonthEnd } from './storage'

const ALARM_NAME = 'costdev_budget_check'

chrome.runtime.onInstalled.addListener(async () => {
  await chrome.alarms.create(ALARM_NAME, { periodInMinutes: 60 })
})

chrome.alarms.onAlarm.addListener(async (alarm) => {
  if (alarm.name !== ALARM_NAME) return
  const state = await loadState()
  if (!state.budget.enabled || state.budget.monthlyLimit <= 0) return

  const spent = sumMonthUsages(state.usages)
  const limit = state.budget.monthlyLimit
  const threshold = limit * state.budget.alertThreshold

  if (spent >= threshold && spent < limit) {
    const last = state.lastAlertAt ?? 0
    if (Date.now() - last > 24 * 60 * 60 * 1000) {
      chrome.notifications.create('costdev-warning', {
        type: 'basic',
        iconUrl: 'icons/icon128.png',
        title: 'Cost.dev — Budget Alert',
        message: `You've spent $${spent.toFixed(2)} of your $${limit.toFixed(2)} monthly budget.`,
        priority: 1,
      })
      state.lastAlertAt = Date.now()
      await saveState(state)
    }
  }

  if (spent >= limit) {
    const last = state.lastAlertAt ?? 0
    if (Date.now() - last > 24 * 60 * 60 * 1000) {
      chrome.notifications.create('costdev-over', {
        type: 'basic',
        iconUrl: 'icons/icon128.png',
        title: 'Cost.dev — Budget Overrun',
        message: `You've exceeded your $${limit.toFixed(2)} monthly budget! Current spend: $${spent.toFixed(2)}.`,
        priority: 2,
      })
      state.lastAlertAt = Date.now()
      await saveState(state)
    }
  }
})

chrome.runtime.onMessage.addListener((message, _sender, sendResponse) => {
  ;(async () => {
    if (message.type === 'budget-check') {
      const state = await loadState()
      const spent = sumMonthUsages(state.usages)
      const limit = state.budget.monthlyLimit
      const projected = projectedMonthEnd(spent)
      sendResponse({ spent, limit, projected, enabled: state.budget.enabled })
    } else {
      sendResponse({ ok: false })
    }
  })()
  return true
})