package com.socialapp.presentation.viewmodel

import androidx.compose.runtime.State
import androidx.compose.runtime.mutableStateOf
import androidx.lifecycle.ViewModel
import androidx.lifecycle.viewModelScope
import com.socialapp.data.api.ApiService
import com.socialapp.data.api.Post
import dagger.hilt.android.lifecycle.HiltViewModel
import kotlinx.coroutines.launch
import javax.inject.Inject

@HiltViewModel
class PostViewModel @Inject constructor(
    private val apiService: ApiService
) : ViewModel() {

    private val _posts = mutableStateOf<List<Post>>(emptyList())
    val posts: State<List<Post>> = _posts

    private val _isLoading = mutableStateOf(false)
    val isLoading: State<Boolean> = _isLoading

    private val _errorMessage = mutableStateOf<String?>(null)
    val errorMessage: State<String?> = _errorMessage

    private var currentPage = 1

    fun loadPosts(page: Int = 1) {
        viewModelScope.launch {
            _isLoading.value = true
            _errorMessage.value = null

            try {
                val response = apiService.getPosts(page = page)
                if (response.isSuccessful && response.body() != null) {
                    val paginatedData = response.body()!!
                    _posts.value = if (page == 1) {
                        paginatedData.data
                    } else {
                        _posts.value + paginatedData.data
                    }
                    currentPage = page
                } else {
                    _errorMessage.value = response.message() ?: "Failed to load posts"
                }
            } catch (e: Exception) {
                _errorMessage.value = e.message ?: "Network error"
            } finally {
                _isLoading.value = false
            }
        }
    }

    fun likePost(postId: Int) {
        viewModelScope.launch {
            try {
                val response = apiService.likePost(postId)
                if (response.isSuccessful) {
                    // Update local state
                    _posts.value = _posts.value.map { post ->
                        if (post.id == postId) {
                            post.copy(
                                isLiked = true,
                                likesCount = post.likesCount + 1
                            )
                        } else {
                            post
                        }
                    }
                }
            } catch (e: Exception) {
                _errorMessage.value = e.message ?: "Failed to like post"
            }
        }
    }

    fun unlikePost(postId: Int) {
        viewModelScope.launch {
            try {
                val response = apiService.unlikePost(postId)
                if (response.isSuccessful) {
                    // Update local state
                    _posts.value = _posts.value.map { post ->
                        if (post.id == postId) {
                            post.copy(
                                isLiked = false,
                                likesCount = maxOf(0, post.likesCount - 1)
                            )
                        } else {
                            post
                        }
                    }
                }
            } catch (e: Exception) {
                _errorMessage.value = e.message ?: "Failed to unlike post"
            }
        }
    }

    fun loadMorePosts() {
        loadPosts(page = currentPage + 1)
    }

    fun clearError() {
        _errorMessage.value = null
    }
}