package com.peachpasswords.sync

import android.content.Context
import android.content.Intent
import android.net.Uri
import android.os.PowerManager
import android.provider.Settings

/**
 * Asks once to be left out of Doze / App Standby.
 *
 * Without it, a phone that has been idle for a while stops answering, and the
 * failure is invisible: a browser dialing a cached address just times out, which
 * is indistinguishable from the phone being off the network. The foreground
 * service keeps the process alive but does not by itself stop Doze from
 * deferring network work.
 *
 * Deliberately only offered once and never nagged — the system dialog is
 * alarming ("let this app run in the background all the time?"), and a user who
 * says no should get a phone that syncs when they open the app rather than one
 * that keeps asking. [isExempt] lets settings show the real state instead of
 * assuming the request worked.
 */
object BatteryExemption {

    private const val PREFS = "peach_sync_battery"
    private const val ASKED_KEY = "asked_exemption"

    fun isExempt(context: Context): Boolean {
        val pm = context.getSystemService(Context.POWER_SERVICE) as? PowerManager ?: return false
        return pm.isIgnoringBatteryOptimizations(context.packageName)
    }

    fun shouldAsk(context: Context): Boolean =
        !isExempt(context) && !context.getSharedPreferences(PREFS, Context.MODE_PRIVATE)
            .getBoolean(ASKED_KEY, false)

    /**
     * Returns the intent to launch, or null when there is nothing to ask for.
     * The caller launches it so the result lands on a real Activity.
     */
    fun requestIntent(context: Context): Intent? {
        if (!shouldAsk(context)) return null
        context.getSharedPreferences(PREFS, Context.MODE_PRIVATE)
            .edit().putBoolean(ASKED_KEY, true).apply()
        return Intent(
            Settings.ACTION_REQUEST_IGNORE_BATTERY_OPTIMIZATIONS,
            Uri.parse("package:${context.packageName}"),
        )
    }
}