// Copyright 2015-present 650 Industries. All rights reserved.
package host.exp.exponent.di

import android.app.Application
import android.content.Context
import android.os.Handler
import android.os.Looper
import com.facebook.proguard.annotations.DoNotStrip
import expo.modules.updates.db.DatabaseHolder
import expo.modules.updates.db.UpdatesDatabase
import host.exp.exponent.ExpoHandler
import host.exp.exponent.ExponentManifest
import host.exp.exponent.analytics.EXL
import host.exp.exponent.kernel.Crypto
import host.exp.exponent.kernel.services.ExpoKernelServiceRegistry
import host.exp.exponent.network.ExponentNetwork
import host.exp.exponent.storage.ExponentSharedPreferences
import java.lang.reflect.Field
import javax.inject.Inject

class NativeModuleDepsProvider(application: Application) {
  @Inject
  @DoNotStrip
  val mContext: Context = application

  @Inject
  @DoNotStrip
  val mApplicationContext: Application = application

  @Inject
  @DoNotStrip
  val mExpoHandler: ExpoHandler = ExpoHandler(Handler(Looper.getMainLooper()))

  @Inject
  @DoNotStrip
  val mExponentSharedPreferences: ExponentSharedPreferences = ExponentSharedPreferences(mContext)

  @Inject
  @DoNotStrip
  val mExponentNetwork: ExponentNetwork = ExponentNetwork(mContext, mExponentSharedPreferences)

  @Inject
  @DoNotStrip
  val mCrypto: Crypto = Crypto(mExponentNetwork)

  @Inject
  @DoNotStrip
  var mExponentManifest: ExponentManifest = ExponentManifest(mContext, mExponentNetwork, mCrypto, mExponentSharedPreferences)

  @Inject
  @DoNotStrip
  var mKernelServiceRegistry: ExpoKernelServiceRegistry = ExpoKernelServiceRegistry(mContext, mExponentSharedPreferences)

  @Inject
  @DoNotStrip
  val mUpdatesDatabaseHolder: DatabaseHolder = DatabaseHolder(UpdatesDatabase.getInstance(mContext))

  private val classToInstanceMap = mutableMapOf<Class<*>, Any>()

  fun add(clazz: Class<*>, instance: Any) {
    classToInstanceMap[clazz] = instance
  }

  fun inject(clazz: Class<*>, target: Any) {
    for (field in clazz.declaredFields) {
      injectFieldInTarget(target, field)
    }
  }

  private fun injectFieldInTarget(target: Any, field: Field) {
    if (field.isAnnotationPresent(Inject::class.java)) {
      val fieldClazz = field.type
      if (!classToInstanceMap.containsKey(fieldClazz)) {
        throw RuntimeException("NativeModuleDepsProvider could not find object for class $fieldClazz")
      }
      val instance = classToInstanceMap[fieldClazz]
      try {
        field.isAccessible = true
        field[target] = instance
      } catch (e: IllegalAccessException) {
        EXL.e(TAG, e.toString())
      }
    }
  }

  companion object {
    private val TAG = NativeModuleDepsProvider::class.java.simpleName

    @JvmStatic lateinit var instance: NativeModuleDepsProvider
      private set

    private var useTestInstance = false

    fun initialize(application: Application) {
      if (!useTestInstance) {
        instance = NativeModuleDepsProvider(application)
      }
    }

    // Only for testing!
    fun setTestInstance(instance: NativeModuleDepsProvider) {
      Companion.instance = instance
      useTestInstance = true
    }
  }

  init {
    for (field in NativeModuleDepsProvider::class.java.declaredFields) {
      if (field.isAnnotationPresent(Inject::class.java)) {
        try {
          classToInstanceMap[field.type] = field[this]
        } catch (e: IllegalAccessException) {
          EXL.e(TAG, e.toString())
        }
      }
    }
  }
}