package com.estateunified.panel

import com.google.gson.Gson
import com.google.gson.reflect.TypeToken
import java.nio.charset.StandardCharsets
import java.nio.file.Files
import java.nio.file.Path
import java.util.UUID

internal data class SavedSearchDto(
    val id: String = "ss-${UUID.randomUUID().toString().take(8)}",
    val ownerUserId: String,
    val name: String,
    val dealType: String = "",
    val segment: String = "",
    val marz: String = "",
    val priceMin: Long? = null,
    val priceMax: Long? = null,
    val rooms: Int? = null,
    val query: String = "",

    val seenSnapshot: Int = 0,

    val seenListingIds: List<String> = emptyList(),
    val notifyEnabled: Boolean = true,
    val createdAtIso: String =
        java.time.format.DateTimeFormatter.ISO_LOCAL_DATE_TIME.format(java.time.LocalDateTime.now()),
)

internal class SavedSearchesStore(
    private val gson: Gson,
    private val file: Path,
) {
    private val lock = Any()

    fun listForUser(userId: String): List<SavedSearchDto> =
        synchronized(lock) { load().filter { it.ownerUserId == userId } }

    fun add(dto: SavedSearchDto): SavedSearchDto =
        synchronized(lock) {
            val list = load().toMutableList()
            list.add(0, dto)
            persist(list)
            dto
        }

    fun delete(id: String, userId: String): Boolean =
        synchronized(lock) {
            val list = load().toMutableList()
            val removed = list.removeIf { it.id == id && it.ownerUserId == userId }
            if (removed) persist(list)
            removed
        }

    fun markSeen(id: String, userId: String, currentIds: List<String>): SavedSearchDto? =
        synchronized(lock) {
            val list = load().toMutableList()
            val idx = list.indexOfFirst { it.id == id && it.ownerUserId == userId }
            if (idx < 0) return@synchronized null
            val updated = list[idx].copy(seenSnapshot = currentIds.size, seenListingIds = currentIds)
            list[idx] = updated
            persist(list)
            updated
        }

    private fun load(): MutableList<SavedSearchDto> {
        if (!Files.isRegularFile(file)) return mutableListOf()
        val text = Files.readString(file, StandardCharsets.UTF_8)
        if (text.isBlank()) return mutableListOf()
        return runCatching {
            gson.fromJson<MutableList<SavedSearchDto>>(text, listType) ?: mutableListOf()
        }.getOrElse { mutableListOf() }
    }

    private fun persist(list: List<SavedSearchDto>) {
        Files.createDirectories(file.toAbsolutePath().parent)
        Files.writeString(file, gson.toJson(list), StandardCharsets.UTF_8)
    }

    companion object {
        private val listType = object : TypeToken<MutableList<SavedSearchDto>>() {}.type
    }
}