package com.example.mycrib.cache

import com.example.mycrib.models.*
import kotlinx.coroutines.flow.MutableStateFlow
import kotlinx.coroutines.flow.StateFlow
import kotlinx.coroutines.flow.asStateFlow
import kotlin.time.Clock
import kotlin.time.ExperimentalTime

//import kotlinx.datetime.Clock
//import kotlinx.datetime.Instant

/**
 * Centralized data cache for the application.
 * This singleton holds all frequently accessed data in memory to avoid redundant API calls.
 */
object DataCache {

    // User & Authentication
    private val _currentUser = MutableStateFlow<User?>(null)
    val currentUser: StateFlow<User?> = _currentUser.asStateFlow()

    // Residences
    private val _residences = MutableStateFlow<List<Residence>>(emptyList())
    val residences: StateFlow<List<Residence>> = _residences.asStateFlow()

    private val _myResidences = MutableStateFlow<MyResidencesResponse?>(null)
    val myResidences: StateFlow<MyResidencesResponse?> = _myResidences.asStateFlow()

    private val _residenceSummaries = MutableStateFlow<Map<Int, ResidenceSummaryResponse>>(emptyMap())
    val residenceSummaries: StateFlow<Map<Int, ResidenceSummaryResponse>> = _residenceSummaries.asStateFlow()

    // Tasks
    private val _allTasks = MutableStateFlow<TaskColumnsResponse?>(null)
    val allTasks: StateFlow<TaskColumnsResponse?> = _allTasks.asStateFlow()

    private val _tasksByResidence = MutableStateFlow<Map<Int, TaskColumnsResponse>>(emptyMap())
    val tasksByResidence: StateFlow<Map<Int, TaskColumnsResponse>> = _tasksByResidence.asStateFlow()

    // Documents
    private val _documents = MutableStateFlow<List<Document>>(emptyList())
    val documents: StateFlow<List<Document>> = _documents.asStateFlow()

    private val _documentsByResidence = MutableStateFlow<Map<Int, List<Document>>>(emptyMap())
    val documentsByResidence: StateFlow<Map<Int, List<Document>>> = _documentsByResidence.asStateFlow()

    // Contractors
    private val _contractors = MutableStateFlow<List<Contractor>>(emptyList())
    val contractors: StateFlow<List<Contractor>> = _contractors.asStateFlow()

    // Lookups/Reference Data
    private val _residenceTypes = MutableStateFlow<List<ResidenceType>>(emptyList())
    val residenceTypes: StateFlow<List<ResidenceType>> = _residenceTypes.asStateFlow()

    private val _taskFrequencies = MutableStateFlow<List<TaskFrequency>>(emptyList())
    val taskFrequencies: StateFlow<List<TaskFrequency>> = _taskFrequencies.asStateFlow()

    private val _taskPriorities = MutableStateFlow<List<TaskPriority>>(emptyList())
    val taskPriorities: StateFlow<List<TaskPriority>> = _taskPriorities.asStateFlow()

    private val _taskStatuses = MutableStateFlow<List<TaskStatus>>(emptyList())
    val taskStatuses: StateFlow<List<TaskStatus>> = _taskStatuses.asStateFlow()

    private val _taskCategories = MutableStateFlow<List<TaskCategory>>(emptyList())
    val taskCategories: StateFlow<List<TaskCategory>> = _taskCategories.asStateFlow()

    private val _contractorSpecialties = MutableStateFlow<List<ContractorSpecialty>>(emptyList())
    val contractorSpecialties: StateFlow<List<ContractorSpecialty>> = _contractorSpecialties.asStateFlow()

    private val _lookupsInitialized = MutableStateFlow(false)
    val lookupsInitialized: StateFlow<Boolean> = _lookupsInitialized.asStateFlow()

    // Cache metadata
    private val _lastRefreshTime = MutableStateFlow<Long>(0L)
    val lastRefreshTime: StateFlow<Long> = _lastRefreshTime.asStateFlow()

    private val _isCacheInitialized = MutableStateFlow(false)
    val isCacheInitialized: StateFlow<Boolean> = _isCacheInitialized.asStateFlow()

    // Update methods
    fun updateCurrentUser(user: User?) {
        _currentUser.value = user
    }

    fun updateResidences(residences: List<Residence>) {
        _residences.value = residences
        updateLastRefreshTime()
    }

    fun updateMyResidences(myResidences: MyResidencesResponse) {
        _myResidences.value = myResidences
        updateLastRefreshTime()
    }

    fun updateResidenceSummary(residenceId: Int, summary: ResidenceSummaryResponse) {
        _residenceSummaries.value = _residenceSummaries.value + (residenceId to summary)
    }

    fun updateAllTasks(tasks: TaskColumnsResponse) {
        _allTasks.value = tasks
        updateLastRefreshTime()
    }

    fun updateTasksByResidence(residenceId: Int, tasks: TaskColumnsResponse) {
        _tasksByResidence.value = _tasksByResidence.value + (residenceId to tasks)
    }

    fun updateDocuments(documents: List<Document>) {
        _documents.value = documents
        updateLastRefreshTime()
    }

    fun updateDocumentsByResidence(residenceId: Int, documents: List<Document>) {
        _documentsByResidence.value = _documentsByResidence.value + (residenceId to documents)
    }

    fun updateContractors(contractors: List<Contractor>) {
        _contractors.value = contractors
        updateLastRefreshTime()
    }

    // Lookup update methods removed - lookups are handled by LookupsViewModel

    fun setCacheInitialized(initialized: Boolean) {
        _isCacheInitialized.value = initialized
    }

    @OptIn(ExperimentalTime::class)
    private fun updateLastRefreshTime() {
        _lastRefreshTime.value = Clock.System.now().toEpochMilliseconds()
    }

    // Helper methods to add/update/remove individual items
    fun addResidence(residence: Residence) {
        _residences.value = _residences.value + residence
    }

    fun updateResidence(residence: Residence) {
        _residences.value = _residences.value.map {
            if (it.id == residence.id) residence else it
        }
    }

    fun removeResidence(residenceId: Int) {
        _residences.value = _residences.value.filter { it.id != residenceId }
        // Also clear related caches
        _tasksByResidence.value = _tasksByResidence.value - residenceId
        _documentsByResidence.value = _documentsByResidence.value - residenceId
        _residenceSummaries.value = _residenceSummaries.value - residenceId
    }

    fun addDocument(document: Document) {
        _documents.value = _documents.value + document
    }

    fun updateDocument(document: Document) {
        _documents.value = _documents.value.map {
            if (it.id == document.id) document else it
        }
    }

    fun removeDocument(documentId: Int) {
        _documents.value = _documents.value.filter { it.id != documentId }
    }

    fun addContractor(contractor: Contractor) {
        _contractors.value = _contractors.value + contractor
    }

    fun updateContractor(contractor: Contractor) {
        _contractors.value = _contractors.value.map {
            if (it.id == contractor.id) contractor else it
        }
    }

    fun removeContractor(contractorId: Int) {
        _contractors.value = _contractors.value.filter { it.id != contractorId }
    }

    // Lookup update methods
    fun updateResidenceTypes(types: List<ResidenceType>) {
        _residenceTypes.value = types
    }

    fun updateTaskFrequencies(frequencies: List<TaskFrequency>) {
        _taskFrequencies.value = frequencies
    }

    fun updateTaskPriorities(priorities: List<TaskPriority>) {
        _taskPriorities.value = priorities
    }

    fun updateTaskStatuses(statuses: List<TaskStatus>) {
        _taskStatuses.value = statuses
    }

    fun updateTaskCategories(categories: List<TaskCategory>) {
        _taskCategories.value = categories
    }

    fun updateContractorSpecialties(specialties: List<ContractorSpecialty>) {
        _contractorSpecialties.value = specialties
    }

    fun updateAllLookups(staticData: StaticDataResponse) {
        _residenceTypes.value = staticData.residenceTypes
        _taskFrequencies.value = staticData.taskFrequencies
        _taskPriorities.value = staticData.taskPriorities
        _taskStatuses.value = staticData.taskStatuses
        _taskCategories.value = staticData.taskCategories
        _contractorSpecialties.value = staticData.contractorSpecialties
    }

    fun markLookupsInitialized() {
        _lookupsInitialized.value = true
    }

    // Clear methods
    fun clearAll() {
        _currentUser.value = null
        _residences.value = emptyList()
        _myResidences.value = null
        _residenceSummaries.value = emptyMap()
        _allTasks.value = null
        _tasksByResidence.value = emptyMap()
        _documents.value = emptyList()
        _documentsByResidence.value = emptyMap()
        _contractors.value = emptyList()
        clearLookups()
        _lastRefreshTime.value = 0L
        _isCacheInitialized.value = false
    }

    fun clearLookups() {
        _residenceTypes.value = emptyList()
        _taskFrequencies.value = emptyList()
        _taskPriorities.value = emptyList()
        _taskStatuses.value = emptyList()
        _taskCategories.value = emptyList()
        _contractorSpecialties.value = emptyList()
        _lookupsInitialized.value = false
    }

    fun clearUserData() {
        _currentUser.value = null
        _residences.value = emptyList()
        _myResidences.value = null
        _residenceSummaries.value = emptyMap()
        _allTasks.value = null
        _tasksByResidence.value = emptyMap()
        _documents.value = emptyList()
        _documentsByResidence.value = emptyMap()
        _contractors.value = emptyList()
        _isCacheInitialized.value = false
    }
}