/*
 * Copyright (C) 2025 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.android.settings.supervision

import android.app.Activity
import android.app.settings.SettingsEnums.ACTION_SUPERVISION_MAIN_TOGGLE_OFF
import android.app.settings.SettingsEnums.ACTION_SUPERVISION_MAIN_TOGGLE_ON
import android.app.supervision.SupervisionManager
import android.content.Context
import android.content.Intent
import android.os.UserHandle
import android.os.UserManager
import android.util.Log
import androidx.annotation.VisibleForTesting
import androidx.appcompat.app.AlertDialog
import androidx.preference.Preference
import com.android.settings.R
import com.android.settings.overlay.FeatureFactory
import com.android.settings.supervision.ipc.PreferenceData
import com.android.settingslib.HelpUtils
import com.android.settingslib.datastore.KeyValueStore
import com.android.settingslib.datastore.NoOpKeyedObservable
import com.android.settingslib.metadata.BooleanValuePreference
import com.android.settingslib.metadata.PreferenceLifecycleContext
import com.android.settingslib.metadata.PreferenceLifecycleProvider
import com.android.settingslib.metadata.PreferenceMetadata
import com.android.settingslib.metadata.PreferenceSummaryProvider
import com.android.settingslib.metadata.ReadWritePermit
import com.android.settingslib.metadata.SensitivityLevel
import com.android.settingslib.preference.forEachRecursively
import com.android.settingslib.supervision.SupervisionLog.TAG
import com.android.settingslib.widget.MainSwitchPreference
import com.android.settingslib.widget.MainSwitchPreferenceBinding
import kotlinx.coroutines.CoroutineDispatcher
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.launch
import kotlinx.coroutines.withContext

/** Main toggle to enable or disable device supervision. */
class SupervisionMainSwitchPreference(
    context: Context,
    private val preferenceDataProvider: PreferenceDataProvider,
    private val coroutineDispatcher: CoroutineDispatcher = Dispatchers.IO,
) :
    BooleanValuePreference,
    MainSwitchPreferenceBinding,
    PreferenceSummaryProvider,
    Preference.OnPreferenceChangeListener,
    PreferenceLifecycleProvider {

    private val supervisionMainSwitchStorage = SupervisionMainSwitchStorage(context)
    private var preferenceDataMap: Map<String, PreferenceData>? = null
    private lateinit var lifeCycleContext: PreferenceLifecycleContext
    private var pendingNewValue: Boolean? = null

    override val key
        get() = KEY

    override val title
        get() = R.string.device_supervision_switch_title

    override fun getSummary(context: Context): CharSequence? =
        if (!context.isSupervisingCredentialSet) {
            context.getString(R.string.device_supervision_switch_no_pin_summary)
        } else {
            null
        }

    override fun storage(context: Context): KeyValueStore = supervisionMainSwitchStorage

    override fun getReadPermit(context: Context, callingPid: Int, callingUid: Int) =
        ReadWritePermit.DISALLOW

    override fun getWritePermit(context: Context, callingPid: Int, callingUid: Int) =
        ReadWritePermit.DISALLOW

    override val sensitivityLevel: Int
        get() = SensitivityLevel.HIGH_SENSITIVITY

    override fun onCreate(context: PreferenceLifecycleContext) {
        lifeCycleContext = context
    }

    override fun onResume(context: PreferenceLifecycleContext) {
        val mainSwitchPreference = context.findPreference<Preference>(KEY)
        updateDependentPreferencesEnabledState(
            mainSwitchPreference,
            supervisionMainSwitchStorage.getBoolean(KEY)!!,
        )

        val preferenceKeys =
            buildList<String> {
                mainSwitchPreference?.parent?.forEachRecursively {
                    if (it.parent?.key == SupervisionDashboardScreen.SUPERVISION_DYNAMIC_GROUP_1) {
                        add(it.key)
                    }
                }
            }

        context.lifecycleScope.launch {
            val cachedData = preferenceDataProvider.getCachedPreferenceData(preferenceKeys)

            if (cachedData.isNotEmpty()) {
                preferenceDataMap = cachedData
                updateDependentPreferenceSummary(mainSwitchPreference)
            }

            // TODO(b/426048474): when navigating from supervision app back to dashboard, the
            // settings injection often overrides the first preference data update, here we
            // are always updating the preference again after fetching fresh data to mitigate the
            // issue.
            preferenceDataMap =
                withContext(coroutineDispatcher) {
                    preferenceDataProvider.getPreferenceData(preferenceKeys)
                }
            updateDependentPreferenceSummary(mainSwitchPreference)
        }
    }

    override fun onActivityResult(
        unused: PreferenceLifecycleContext,
        requestCode: Int,
        resultCode: Int,
        data: Intent?,
    ): Boolean {
        if (
            requestCode != REQUEST_CODE_SET_UP_SUPERVISION &&
                requestCode != REQUEST_CODE_CONFIRM_SUPERVISION_CREDENTIALS
        ) {
            return false
        }
        if (resultCode == Activity.RESULT_OK) {
            val mainSwitchPreference = lifeCycleContext.requirePreference<MainSwitchPreference>(KEY)

            // Determine the new switch value based on the request code.
            // For setup, as setup activity will always set the value to true,
            // we need to use the pending value.
            // For confirmation, toggle the current value.
            val newValue =
                if (requestCode == REQUEST_CODE_SET_UP_SUPERVISION) {
                    pendingNewValue ?: false
                } else {
                    !supervisionMainSwitchStorage.getBoolean(KEY)!!
                }
            pendingNewValue = null
            mainSwitchPreference.setChecked(newValue)
            lifeCycleContext.notifyPreferenceChange(KEY)
            updateDependentPreferencesEnabledState(mainSwitchPreference, newValue)
            updateDependentPreferenceSummary(mainSwitchPreference)
            lifeCycleContext.notifyPreferenceChange(SupervisionPinManagementScreen.KEY)

            FeatureFactory.featureFactory.metricsFeatureProvider.action(
                lifeCycleContext,
                if (newValue) ACTION_SUPERVISION_MAIN_TOGGLE_ON
                else ACTION_SUPERVISION_MAIN_TOGGLE_OFF,
            )
        }

        return true
    }

    override fun bind(preference: Preference, metadata: PreferenceMetadata) {
        super.bind(preference, metadata)
        preference.onPreferenceChangeListener = this
    }

    override fun onPreferenceChange(preference: Preference, newValue: Any?): Boolean {
        if (newValue !is Boolean) return true

        // Only perform these checks when the user is turning supervision ON.
        if (newValue) {
            val userManager = preference.context.getSystemService(UserManager::class.java)
            if (userManager != null) {
                val supervisingProfileHandle: UserHandle? = preference.context.supervisingUserHandle
                val nonSupervisingProfiles =
                    userManager.userProfiles.filter { it != supervisingProfileHandle }

                // If more than one profile remains (the main user + another), block enabling
                // supervision.
                if (nonSupervisingProfiles.size > 1) {
                    AlertDialog.Builder(preference.context)
                        .setTitle(R.string.supervision_multi_profile_error_title)
                        .setMessage(R.string.supervision_multi_profile_error_message)
                        .setPositiveButton(android.R.string.ok, null)
                        .setNeutralButton(R.string.learn_more, { _, _ -> onLearnMore() })
                        .show()
                    return false
                }
            }
        }

        // If supervision is being toggled but either the supervising profile hasn't been
        // created or the credentials aren't set, launch SetupSupervisionActivity.
        if (!preference.context.isSupervisingCredentialSet) {
            pendingNewValue = newValue
            val intent = Intent(lifeCycleContext, SetupSupervisionActivity::class.java)
            lifeCycleContext.startActivityForResult(intent, REQUEST_CODE_SET_UP_SUPERVISION, null)
            return false
        }

        // If supervision is already set up, confirm credentials before any change.
        val intent =
            Intent(lifeCycleContext, ConfirmSupervisionCredentialsActivity::class.java).apply {
                putExtra(ConfirmSupervisionCredentialsActivity.EXTRA_FORCE_CONFIRMATION, true)
            }
        lifeCycleContext.startActivityForResult(
            intent,
            REQUEST_CODE_CONFIRM_SUPERVISION_CREDENTIALS,
            null,
        )
        return false
    }

    private fun updateDependentPreferencesEnabledState(
        preference: Preference?,
        isChecked: Boolean,
    ) {
        preference?.parent?.forEachRecursively {
            if (it.parent?.key == SupervisionDashboardScreen.SUPERVISION_DYNAMIC_GROUP_1) {
                it.isEnabled = isChecked
            }
        }
    }

    private fun updateDependentPreferenceSummary(preference: Preference?) {
        preference?.parent?.forEachRecursively {
            if (it.parent?.key == SupervisionDashboardScreen.SUPERVISION_DYNAMIC_GROUP_1) {
                val newSummary = preferenceDataMap?.get(it.key)?.summary
                if (newSummary != null) {
                    it.summary = newSummary
                }
            }
        }
    }

    private fun onLearnMore() {
        val intent =
            HelpUtils.getHelpIntent(
                lifeCycleContext,
                lifeCycleContext.getString(R.string.supervision_unavailable_learn_more_link),
                lifeCycleContext::class.java.name,
            )
        if (intent != null) {
            lifeCycleContext.startActivity(intent)
        } else {
            Log.w(TAG, "HelpIntent is null")
        }
    }

    @Suppress("UNCHECKED_CAST")
    private class SupervisionMainSwitchStorage(private val context: Context) :
        NoOpKeyedObservable<String>(), KeyValueStore {
        override fun contains(key: String) = key == KEY

        override fun <T : Any> getValue(key: String, valueType: Class<T>) =
            (context.getSystemService(SupervisionManager::class.java)?.isSupervisionEnabled() ==
                true)
                as T

        override fun <T : Any> setValue(key: String, valueType: Class<T>, value: T?) {
            if (key == KEY && value is Boolean) {
                val supervisionManager = context.getSystemService(SupervisionManager::class.java)
                supervisionManager?.setSupervisionEnabled(value)
            }
        }
    }

    companion object {
        const val KEY = "device_supervision_switch"
        @VisibleForTesting const val REQUEST_CODE_CONFIRM_SUPERVISION_CREDENTIALS = 0
        @VisibleForTesting const val REQUEST_CODE_SET_UP_SUPERVISION = 1
    }
}