package com.rizoma.orbita.ui

import android.app.Application
import android.content.BroadcastReceiver
import android.content.ComponentName
import android.content.Context
import android.content.Intent
import android.content.IntentFilter
import android.net.Uri
import android.provider.Settings
import androidx.lifecycle.AndroidViewModel
import androidx.lifecycle.viewModelScope
import com.rizoma.orbita.data.AppRepository
import com.rizoma.orbita.data.SkyRepository
import com.rizoma.orbita.data.UsageStore
import com.rizoma.orbita.data.Weather
import com.rizoma.orbita.model.AppNode
import com.rizoma.orbita.model.Buckets
import com.rizoma.orbita.model.ExpelledNode
import com.rizoma.orbita.model.SearchSort
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.delay
import kotlinx.coroutines.flow.MutableStateFlow
import kotlinx.coroutines.flow.SharingStarted
import kotlinx.coroutines.flow.StateFlow
import kotlinx.coroutines.flow.asStateFlow
import kotlinx.coroutines.flow.combine
import kotlinx.coroutines.flow.flow
import kotlinx.coroutines.flow.map
import kotlinx.coroutines.flow.stateIn
import kotlinx.coroutines.launch
import java.util.Calendar

class OrbitaViewModel(app: Application) : AndroidViewModel(app) {

    private val repo = AppRepository(app)
    private val usage = UsageStore(app)

    private val rawApps = MutableStateFlow<List<AppNode>>(emptyList())

    /** Todas las apps ya ponderadas y ordenadas (fijados, calor, alfabético). Para la búsqueda. */
    val allNodes: StateFlow<List<AppNode>> = combine(rawApps, usage.snapshot()) { apps, u ->
        apps.map { node ->
            node.copy(
                score = (u.counts[node.key] ?: 0).toFloat(),
                pinned = node.key in u.pinned,
                penalty = u.penalties[node.key] ?: 0,
                hidden = node.key in u.hidden,
                hiddenAt = u.hiddenAt[node.key] ?: 0L,
            )
        }.sortedWith(
            compareByDescending<AppNode> { it.pinned }
                .thenByDescending { it.score - (u.penalties[it.key] ?: 0).toFloat() }
                .thenBy { it.label.lowercase() }
        )
    }.stateIn(viewModelScope, SharingStarted.WhileSubscribed(5_000), emptyList())

    /** Las apps repartidas en las cuatro zonas (átomo, nuevas, expulsadas, desterradas). */
    val buckets: StateFlow<Buckets> = allNodes
        .map { classify(it) }
        .stateIn(viewModelScope, SharingStarted.WhileSubscribed(5_000), Buckets(emptyList(), emptyList(), emptyList(), emptyList()))

    private fun classify(nodes: List<AppNode>): Buckets {
        val now = System.currentTimeMillis()
        val nuevas = nodes.filter {
            !it.hidden && it.score == 0f &&
                it.firstInstallTime > 0L && now - it.firstInstallTime < NEW_WINDOW
        }.sortedByDescending { it.firstInstallTime }
        val nuevasKeys = nuevas.mapTo(HashSet()) { it.key }

        val atom = nodes.filter { !it.hidden && it.key !in nuevasKeys }

        val expulsadas = ArrayList<ExpelledNode>()
        val desterradas = ArrayList<AppNode>()
        for (n in nodes.filter { it.hidden }) {
            val age = now - n.hiddenAt
            if (n.hiddenAt > 0L && age < CALM_WINDOW) {
                expulsadas.add(ExpelledNode(n, (1f - age.toFloat() / CALM_WINDOW).coerceIn(0f, 1f)))
            } else {
                desterradas.add(n)
            }
        }
        return Buckets(atom, nuevas, expulsadas, desterradas.sortedBy { it.label.lowercase() })
    }

    // --- Búsqueda: criterio de orden (se recuerda entre sesiones). ---

    /** Cómo se ordena la lista de la búsqueda. Por defecto, por frecuencia de uso. */
    val searchSort: StateFlow<SearchSort> = usage.sortMode()
        .map { SearchSort.from(it) }
        .stateIn(viewModelScope, SharingStarted.WhileSubscribed(5_000), SearchSort.FRECUENCIA)

    fun setSearchSort(sort: SearchSort) {
        viewModelScope.launch { usage.setSortMode(sort.name) }
    }

    // --- Cielo del fondo: hora del día + clima local (perezoso). ---

    private val _weather = MutableStateFlow<Weather?>(null)
    /** Clima actual (null hasta que se visita la página de clima). */
    val weather: StateFlow<Weather?> = _weather.asStateFlow()

    /** Marca la hora actual (con fracción) y se reemite cada minuto. */
    private val clock = flow {
        while (true) {
            emit(currentHourFraction())
            delay(60_000L)
        }
    }

    val sky: StateFlow<SkyPalette> = combine(clock, _weather) { hour, w ->
        skyPaletteFor(hour, w)
    }.stateIn(
        viewModelScope,
        SharingStarted.WhileSubscribed(5_000),
        skyPaletteFor(currentHourFraction(), null),
    )

    /**
     * Refresca el clima local (best-effort, una sola vez salvo que se fuerce).
     * Se llama al acercarse a la página de clima: mientras no se abra, no se carga.
     */
    fun ensureWeather() {
        if (_weather.value != null) return
        refreshWeather()
    }

    fun refreshWeather() {
        viewModelScope.launch(Dispatchers.IO) {
            SkyRepository(getApplication()).fetch()?.let { _weather.value = it }
        }
    }

    private fun currentHourFraction(): Float {
        val c = Calendar.getInstance()
        return c.get(Calendar.HOUR_OF_DAY) + c.get(Calendar.MINUTE) / 60f
    }

    private val pkgReceiver = object : BroadcastReceiver() {
        override fun onReceive(context: Context?, intent: Intent?) = refresh()
    }

    init {
        refresh()
        val filter = IntentFilter().apply {
            addAction(Intent.ACTION_PACKAGE_ADDED)
            addAction(Intent.ACTION_PACKAGE_REMOVED)
            addAction(Intent.ACTION_PACKAGE_CHANGED)
            addDataScheme("package")
        }
        getApplication<Application>().registerReceiver(pkgReceiver, filter)
    }

    fun refresh() {
        viewModelScope.launch(Dispatchers.IO) {
            rawApps.value = repo.loadApps()
        }
    }

    fun launch(node: AppNode) {
        val intent = Intent(Intent.ACTION_MAIN)
            .addCategory(Intent.CATEGORY_LAUNCHER)
            .setComponent(ComponentName(node.packageName, node.activityName))
            .addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)
        runCatching { getApplication<Application>().startActivity(intent) }
        viewModelScope.launch { usage.record(node.key) }
    }

    /** Abre una app por nombre de paquete (p.ej. Nimbo desde la página de clima). */
    fun launchPackage(pkg: String): Boolean {
        val intent = getApplication<Application>().packageManager.getLaunchIntentForPackage(pkg)
            ?.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK) ?: return false
        return runCatching { getApplication<Application>().startActivity(intent); true }.getOrDefault(false)
    }

    fun togglePin(node: AppNode) {
        viewModelScope.launch { usage.setPinned(node.key, !node.pinned) }
    }

    /** Expulsa el nodo del átomo (o lo devuelve). No desinstala: la app sigue ahí. */
    fun toggleHidden(node: AppNode) {
        viewModelScope.launch { usage.setHidden(node.key, !node.hidden, System.currentTimeMillis()) }
    }

    /** Aleja el nodo a órbitas externas (usa su calor actual como referencia). */
    fun pushAway(node: AppNode) {
        viewModelScope.launch { usage.pushAway(node.key, node.score.toInt()) }
    }

    fun openInfo(node: AppNode) {
        val intent = Intent(Settings.ACTION_APPLICATION_DETAILS_SETTINGS)
            .setData(Uri.fromParts("package", node.packageName, null))
            .addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)
        runCatching { getApplication<Application>().startActivity(intent) }
    }

    fun uninstall(node: AppNode) {
        @Suppress("DEPRECATION")
        val intent = Intent(Intent.ACTION_DELETE)
            .setData(Uri.fromParts("package", node.packageName, null))
            .addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)
        runCatching { getApplication<Application>().startActivity(intent) }
    }

    override fun onCleared() {
        runCatching { getApplication<Application>().unregisterReceiver(pkgReceiver) }
    }

    private companion object {
        const val NEW_WINDOW = 3L * 24 * 3600 * 1000   // "nueva" durante 3 días
        const val CALM_WINDOW = 7L * 24 * 3600 * 1000  // se calma/destierra en 7 días
    }
}