// MainActivity.kt
package com.example.towhed

import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import androidx.recyclerview.widget.LinearLayoutManager
import com.example.towhed.databinding.ActivityMainBinding
import com.google.firebase.auth.FirebaseAuth
import com.google.firebase.firestore.FirebaseFirestore

class MainActivity : AppCompatActivity() {
    private lateinit var binding: ActivityMainBinding
    private lateinit var auth: FirebaseAuth
    private lateinit var db: FirebaseFirestore
    private lateinit var adapter: MessageAdapter
    private val messages = mutableListOf<Message>()

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        binding = ActivityMainBinding.inflate(layoutInflater)
        setContentView(binding.root)

        auth = FirebaseAuth.getInstance()
        db = FirebaseFirestore.getInstance()

        // Check if user is logged in with admin code
        if (auth.currentUser == null) {
            startActivity(Intent(this, LoginActivity::class.java))
            finish()
            return
        }

        setupRecyclerView()
        setupListeners()
        loadMessages()
    }

    private fun setupRecyclerView() {
        adapter = MessageAdapter(messages)
        binding.recyclerView.apply {
            layoutManager = LinearLayoutManager(this@MainActivity)
            adapter = this@MainActivity.adapter
        }
    }

    private fun setupListeners() {
        binding.sendButton.setOnClickListener {
            val messageText = binding.messageInput.text.toString().trim()
            if (messageText.isNotEmpty()) {
                sendMessage(messageText)
                binding.messageInput.text.clear()
            }
        }
    }

    private fun sendMessage(text: String) {
        val message = Message(
            text = text,
            senderId = auth.currentUser?.uid ?: "",
            timestamp = System.currentTimeMillis()
        )

        db.collection("messages")
            .add(message)
            .addOnSuccessListener {
                // Message sent successfully
            }
            .addOnFailureListener {
                // Handle error
            }
    }

    private fun loadMessages() {
        db.collection("messages")
            .orderBy("timestamp")
            .addSnapshotListener { snapshot, error ->
                if (error != null) return@addSnapshotListener

                messages.clear()
                snapshot?.documents?.forEach { doc ->
                    val message = doc.toObject(Message::class.java)
                    message?.let { messages.add(it) }
                }
                adapter.notifyDataSetChanged()
                binding.recyclerView.scrollToPosition(messages.size - 1)
            }
    }
}

// LoginActivity.kt
package com.example.towhed

import android.content.Intent
import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import com.example.towhed.databinding.ActivityLoginBinding
import com.google.firebase.auth.FirebaseAuth
import com.google.firebase.firestore.FirebaseFirestore

class LoginActivity : AppCompatActivity() {
    private lateinit var binding: ActivityLoginBinding
    private lateinit var auth: FirebaseAuth
    private lateinit var db: FirebaseFirestore

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        binding = ActivityLoginBinding.inflate(layoutInflater)
        setContentView(binding.root)

        auth = FirebaseAuth.getInstance()
        db = FirebaseFirestore.getInstance()

        binding.loginButton.setOnClickListener {
            val phone = binding.phoneInput.text.toString().trim()
            val code = binding.codeInput.text.toString().trim()

            if (phone.isEmpty() || code.isEmpty()) {
                // Show error
                return@setOnClickListener
            }

            verifyAdminCode(phone, code)
        }

        binding.adminLink.setOnClickListener {
            startActivity(Intent(this, AdminActivity::class.java))
        }
    }

    private fun verifyAdminCode(code: String) {
        db.collection("admin_codes")
            .whereEqualTo("code", code)
            .limit(1)
            .get()
            .addOnSuccessListener { doc ->
                if (doc.exists() && doc.getString("code") == code) {
                    // Code is valid, proceed with authentication
                    authenticateUser(phone)
                } else {
                    // Show invalid code error
                }
            }
            .addOnFailureListener {
                // Handle error
            }
    }

    private fun authenticateUser(phone: String) {
        // Implement phone authentication with Firebase
        // On success:
        startActivity(Intent(this, MainActivity::class.java))
        finish()
    }
}

// AdminActivity.kt
package com.example.towhed

import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import com.example.towhed.databinding.ActivityAdminBinding
import com.google.firebase.firestore.FirebaseFirestore
import java.util.*

class AdminActivity : AppCompatActivity() {
    private lateinit var binding: ActivityAdminBinding
    private lateinit var db: FirebaseFirestore

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        binding = ActivityAdminBinding.inflate(layoutInflater)
        setContentView(binding.root)

        db = FirebaseFirestore.getInstance()

        binding.generateButton.setOnClickListener {
            val phone = binding.phoneInput.text.toString().trim()
            if (phone.isEmpty()) return@setOnClickListener

            val code = generateRandomCode()
            binding.codeOutput.setText(code)

            saveAdminCode(phone, code)
        }
    }

    private fun generateRandomCode(): String {
        return (100000..999999).random().toString()
    }

    private fun saveAdminCode(phone: String, code: String) {
        val data = hashMapOf(
            "phone" to phone,
            "code" to code,
            "generatedAt" to System.currentTimeMillis()
        )

        db.collection("admin_codes")
            .document(phone)
            .set(data)
            .addOnSuccessListener {
                // Code saved successfully
            }
            .addOnFailureListener {
                // Handle error
            }
    }
}

// Message.kt
data class Message(
    val text: String = "",
    val senderId: String = "",
    val timestamp: Long = 0L
)

// MessageAdapter.kt
class MessageAdapter(private val messages: List<Message>) : 
    RecyclerView.Adapter<MessageAdapter.MessageViewHolder>() {
    
    inner class MessageViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
        fun bind(message: Message) {
            // Bind message data to views
        }
    }

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): MessageViewHolder {
        val view = LayoutInflater.from(parent.context)
            .inflate(R.layout.item_message, parent, false)
        return MessageViewHolder(view)
    }

    override fun onBindViewHolder(holder: MessageViewHolder, position: Int) {
        holder.bind(messages[position])
    }

    override fun getItemCount(): Int = messages.size
}