package chats.data.local.mappers

import chats.data.local.database.ChatEntity
import chats.domain.model.Chat
import com.google.gson.Gson

private val gson = Gson()

/**
 * Преобразует Domain Chat в Entity
 */
fun Chat.toEntity(): ChatEntity {
    val timestamp = this.lastMessage?.createdAt?.let { parseTimestamp(it) }
    return ChatEntity(
        localId = this.id.takeIf { it.isNotBlank() } ?: java.util.UUID.randomUUID().toString(),
        remoteId = this.id,
        type = this.type,
        name = this.name,
        avatar = this.avatar,
        unreadCount = this.unreadCount,
        lastMessageText = this.lastMessage?.content,
        lastMessageTimestamp = timestamp,
        lastMessageJson = this.lastMessage?.let { gson.toJson(it) }
    )
}

/**
 * Преобразует Entity в Domain Chat
 */
fun ChatEntity.toDomain(): Chat {
    val lastMessage = this.lastMessageJson?.let { json ->
        try {
            gson.fromJson(json, chats.domain.model.Message::class.java)
        } catch (e: Exception) {
            null
        }
    }
    return Chat(
        id = this.remoteId ?: this.localId,
        type = this.type,
        name = this.name,
        avatar = this.avatar,
        unreadCount = this.unreadCount,
        lastMessage = lastMessage
    )
}

/**
 * Парсит ISO-8601 timestamp в Long (millis)
 */
private fun parseTimestamp(isoTimestamp: String): Long? {
    return try {
        java.time.ZonedDateTime.parse(isoTimestamp).toInstant().toEpochMilli()
    } catch (e: Exception) {
        null
    }
}