package id.pribadi.qrisnotifier

import android.content.Context
import android.content.SharedPreferences
import org.json.JSONArray
import org.json.JSONObject
import java.net.HttpURLConnection
import java.net.URL
import java.util.concurrent.atomic.AtomicBoolean

/** Antrean kirim ke server: notifikasi disimpan dulu, dikirim ulang sampai server menjawab. */
object Sender {
    private const val PREF = "qris_notifier"
    private const val MAX_QUEUE = 500
    private val lock = Any()
    private val flushing = AtomicBoolean(false)

    // Paket aplikasi umum. Periksa & sesuaikan dengan aplikasi yang kamu pakai menerima uang.
    const val DEFAULT_PACKAGES =
        "com.gojek.gopaymerchant,com.gojek.app,id.dana,ovo.id,com.shopee.id," +
        "com.telkom.mwallet,com.bca,id.co.bri.brimo,id.bmri.livin,src.com.bni"

    fun prefs(c: Context): SharedPreferences = c.getSharedPreferences(PREF, Context.MODE_PRIVATE)

    /** Mode diagnosa: selama belum lewat batas waktu, SEMUA notifikasi (selain milik aplikasi ini) dikirim. */
    fun diagnosticLeftMs(c: Context): Long =
        maxOf(0L, prefs(c).getLong("diag_until", 0L) - System.currentTimeMillis())

    fun startDiagnostic(c: Context, minutes: Int = 10) {
        prefs(c).edit().putLong("diag_until", System.currentTimeMillis() + minutes * 60_000L).apply()
    }

    fun stopDiagnostic(c: Context) {
        prefs(c).edit().putLong("diag_until", 0L).apply()
    }

    /** Paket ada di daftar pantauan (pembayaran sungguhan, diproses normal oleh server). */
    fun inList(c: Context, pkg: String): Boolean {
        val list = prefs(c).getString("packages", DEFAULT_PACKAGES).orEmpty()
            .split(",").map { it.trim().lowercase() }.filter { it.isNotEmpty() }
        return pkg.lowercase() in list
    }

    fun allowed(c: Context, pkg: String): Boolean =
        inList(c, pkg) || (diagnosticLeftMs(c) > 0 && pkg != c.packageName)

    fun enqueue(c: Context, pkg: String, title: String, text: String, postedAt: Long, diag: Boolean = false) {
        synchronized(lock) {
            val old = JSONArray(prefs(c).getString("queue", "[]"))
            val arr = JSONArray()
            val start = maxOf(0, old.length() - (MAX_QUEUE - 1))
            for (i in start until old.length()) arr.put(old.get(i))
            arr.put(
                JSONObject()
                    .put("package", pkg)
                    .put("title", title)
                    .put("text", text)
                    .put("posted_at", postedAt)
                    .put("diag", diag) // true = hanya untuk dilihat, server tidak mencocokkan dengan order
            )
            prefs(c).edit().putString("queue", arr.toString()).apply()
        }
    }

    fun queueSize(c: Context): Int = synchronized(lock) {
        JSONArray(prefs(c).getString("queue", "[]")).length()
    }

    private fun peek(c: Context): JSONObject? = synchronized(lock) {
        val arr = JSONArray(prefs(c).getString("queue", "[]"))
        if (arr.length() == 0) null else arr.getJSONObject(0)
    }

    private fun pop(c: Context) = synchronized(lock) {
        val arr = JSONArray(prefs(c).getString("queue", "[]"))
        if (arr.length() > 0) {
            arr.remove(0)
            prefs(c).edit().putString("queue", arr.toString()).apply()
        }
    }

    /** Kirim semua isi antrean di thread terpisah. Berhenti pada kegagalan pertama (dicoba lagi nanti). */
    fun flush(c: Context) {
        val app = c.applicationContext
        if (!flushing.compareAndSet(false, true)) return
        Thread {
            try {
                while (true) {
                    val item = peek(app) ?: break
                    if (!post(app, item)) break
                    pop(app)
                }
            } finally {
                flushing.set(false)
            }
        }.start()
    }

    /** true = item selesai (sukses, atau ditolak permanen karena datanya salah) dan boleh dibuang. */
    private fun post(c: Context, item: JSONObject): Boolean {
        val p = prefs(c)
        val base = p.getString("server", "").orEmpty().trim().trimEnd('/')
        val key = p.getString("device_key", "").orEmpty().trim()
        if (base.isEmpty() || key.isEmpty()) return false
        return try {
            val conn = (URL("$base/api/notify.php").openConnection() as HttpURLConnection).apply {
                requestMethod = "POST"
                connectTimeout = 10_000
                readTimeout = 15_000
                doOutput = true
                setRequestProperty("Content-Type", "application/json")
                setRequestProperty("X-Device-Key", key)
            }
            conn.outputStream.use { it.write(item.toString().toByteArray(Charsets.UTF_8)) }
            val code = conn.responseCode
            conn.disconnect()
            p.edit().putString("last", "HTTP $code · ${java.text.SimpleDateFormat("HH:mm:ss").format(java.util.Date())}").apply()
            code in 200..299 || (code in 400..499 && code !in listOf(401, 403, 404, 408, 429))
        } catch (e: Exception) {
            p.edit().putString("last", "Gagal: ${e.javaClass.simpleName}").apply()
            false
        }
    }
}