package com.xuqm.sdk.bugcollect

import android.content.Context
import android.util.Log
import com.xuqm.sdk.bugcollect.internal.LogUploader
import com.xuqm.sdk.bugcollect.internal.LogStorage
import kotlinx.coroutines.CoroutineScope
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.SupervisorJob
import kotlinx.coroutines.delay
import kotlinx.coroutines.launch
import org.json.JSONArray
import org.json.JSONObject
import java.io.File

/** [JSONObject.optString] returns non-null on newer Android; this returns null when the key is absent or the value is null. */
private fun JSONObject.optNullableString(key: String): String? =
    if (has(key) && !isNull(key)) optString(key) else null

internal class LogQueue(
    private val logApiUrl: String,
    private val appKey: String,
    private val appContext: Context,
) {

    companion object {
        private const val TAG = "BugCollect"
        private const val MAX_QUEUE_SIZE = 500
        private const val BATCH_SIZE = 30
        private const val FLUSH_INTERVAL_MS = 10_000L
        private const val PREFS_NAME = "xuqm_log_queue"
        private const val KEY_ISSUES = "issues"
        private const val KEY_EVENTS = "events"
    }

    private val scope = CoroutineScope(SupervisorJob() + Dispatchers.IO)
    private val pendingIssues = mutableListOf<IssueEvent>()
    private val pendingEvents = mutableListOf<LogEvent>()
    private val lock = Any()

    init {
        loadFromDisk()
        scope.launch {
            while (true) {
                delay(FLUSH_INTERVAL_MS)
                flush()
            }
        }
    }

    fun push(event: Any) {
        synchronized(lock) {
            when (event) {
                is IssueEvent -> {
                    if (pendingIssues.size >= MAX_QUEUE_SIZE) pendingIssues.removeAt(0)
                    pendingIssues.add(event)
                }
                is LogEvent -> {
                    if (pendingEvents.size >= MAX_QUEUE_SIZE) pendingEvents.removeAt(0)
                    pendingEvents.add(event)
                }
            }
        }
        if (shouldFlush()) scope.launch { flush() }
    }

    fun uploadPendingCrashes() {
        if (logApiUrl.isBlank()) return
        scope.launch {
            val crashDir = LogStorage.crashDir(appContext)
            val files = crashDir.listFiles() ?: return@launch
            for (file in files) {
                runCatching {
                    val json = file.readText()
                    val obj = JSONObject(json)
                    val event = IssueEvent(
                        type = obj.optString("type", "native_crash"),
                        message = obj.optString("message", ""),
                        stack = obj.optString("stack", ""),
                        fingerprint = Fingerprint.compute("native_crash", obj.optString("message", ""), obj.optString("stack", "")),
                        appKey = obj.optString("appKey", appKey),
                        userId = obj.optNullableString("userId"),
                        platform = "android",
                        appVersion = runCatching {
                            appContext.packageManager.getPackageInfo(appContext.packageName, 0).versionName ?: "unknown"
                        }.getOrDefault("unknown"),
                        metadata = emptyMap(),
                        environment = "production",
                        timestamp = obj.optLong("timestamp", System.currentTimeMillis()),
                    )
                    LogUploader.uploadIssue(logApiUrl, event)
                    file.delete()
                }.onFailure { e ->
                    Log.e(TAG, "Failed to upload crash: ${file.name}", e)
                }
            }
        }
    }

    private fun shouldFlush(): Boolean = synchronized(lock) {
        pendingIssues.size >= BATCH_SIZE || pendingEvents.size >= BATCH_SIZE
    }

    private fun flush() {
        val issues: List<IssueEvent>
        val events: List<LogEvent>
        synchronized(lock) {
            if (pendingIssues.isEmpty() && pendingEvents.isEmpty()) return
            issues = pendingIssues.toList()
            events = pendingEvents.toList()
            pendingIssues.clear()
            pendingEvents.clear()
        }
        if (issues.isNotEmpty()) {
            scope.launch {
                runCatching { LogUploader.uploadIssues(logApiUrl, issues) }
                    .onFailure { e ->
                        Log.e(TAG, "Failed to upload issues batch, re-queuing", e)
                        synchronized(lock) {
                            val remaining = MAX_QUEUE_SIZE - pendingIssues.size
                            if (remaining > 0) pendingIssues.addAll(0, issues.take(remaining))
                        }
                    }
            }
        }
        if (events.isNotEmpty()) {
            scope.launch {
                runCatching { LogUploader.uploadEvents(logApiUrl, events) }
                    .onFailure { e ->
                        Log.e(TAG, "Failed to upload events batch, re-queuing", e)
                        synchronized(lock) {
                            val remaining = MAX_QUEUE_SIZE - pendingEvents.size
                            if (remaining > 0) pendingEvents.addAll(0, events.take(remaining))
                        }
                    }
            }
        }
    }

    private fun loadFromDisk() {
        runCatching {
            val prefs = appContext.getSharedPreferences(PREFS_NAME, Context.MODE_PRIVATE)
            prefs.getString(KEY_ISSUES, null)?.let { json ->
                val arr = JSONArray(json)
                synchronized(lock) {
                    for (i in 0 until arr.length()) {
                        val obj = arr.getJSONObject(i)
                        pendingIssues.add(IssueEvent(
                            type = obj.optString("type", ""),
                            message = obj.optString("message", ""),
                            stack = obj.optString("stack", ""),
                            fingerprint = obj.optString("fingerprint", ""),
                            appKey = obj.optString("appKey", appKey),
                            userId = obj.optNullableString("userId"),
                            platform = obj.optString("platform", "android"),
                            appVersion = obj.optString("appVersion", ""),
                            metadata = emptyMap(),
                            environment = obj.optString("environment", "production"),
                            timestamp = obj.optLong("timestamp", 0),
                        ))
                    }
                }
            }
            prefs.getString(KEY_EVENTS, null)?.let { json ->
                val arr = JSONArray(json)
                synchronized(lock) {
                    for (i in 0 until arr.length()) {
                        val obj = arr.getJSONObject(i)
                        pendingEvents.add(LogEvent(
                            name = obj.optString("name", ""),
                            appKey = obj.optString("appKey", appKey),
                            userId = obj.optNullableString("userId"),
                            platform = obj.optString("platform", "android"),
                            appVersion = obj.optString("appVersion", ""),
                            environment = obj.optString("environment", "production"),
                            timestamp = obj.optLong("timestamp", 0),
                        ))
                    }
                }
            }
            prefs.edit().remove(KEY_ISSUES).remove(KEY_EVENTS).apply()
        }
    }
}