package com.example.firebaseproject

import android.annotation.SuppressLint
import android.content.Context
import android.os.Bundle
import android.text.TextUtils
import android.util.Log
import android.widget.Toast
import androidx.activity.ComponentActivity
import androidx.activity.compose.setContent
import androidx.compose.foundation.background
import androidx.compose.foundation.layout.*
import androidx.compose.material.*
import androidx.compose.runtime.Composable
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.platform.LocalContext
import androidx.compose.ui.text.TextStyle
import androidx.compose.ui.text.style.TextAlign
import androidx.compose.ui.unit.dp
import androidx.compose.ui.unit.sp
import com.example.firebaseproject.ui.theme.FirebaseProjectTheme
import com.example.firebaseproject.ui.theme.greenColor
import com.google.firebase.firestore.CollectionReference
import com.google.firebase.firestore.FirebaseFirestore

class MainActivity : ComponentActivity() {
    @SuppressLint("UnrememberedMutableState")
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent {
            FirebaseProjectTheme {
                // A surface container using the 'background' color from the theme
                Surface(
                    // on below line we are specifying modifier and color for our app
                    modifier = Modifier.fillMaxSize(), color = MaterialTheme.colors.background
                ) {
                    // on the below line we are specifying the theme as the scaffold.
                    Scaffold(
                        // in scaffold we are specifying the top bar.
                        topBar = {
                            // inside top bar we are specifying background color.
                            TopAppBar(backgroundColor = greenColor,
                                // along with that we are specifying
                                // title for our top bar.
                                title = {
                                    // in the top bar we are
                                    // specifying tile as a text
                                    Text(
                                        // on below line we are specifying
                                        // text to display in top app bar
                                        text = "GFG",
                                        // on below line we are specifying
                                        // modifier to fill max width
                                        modifier = Modifier.fillMaxWidth(),
                                        // on below line we are
                                        // specifying text alignment
                                        textAlign = TextAlign.Center,
                                        // on below line we are specifying
                                        // color for our text.
                                        color = Color.White
                                    )
                                })
                        }) {
                        // on below line we are calling
                        // method to display UI
                        firebaseUI(LocalContext.current)
                    }
                }
            }
        }
    }
}

@Composable
fun firebaseUI(context: Context) {

    // on below line creating variable for course name,
    // course duration and course description.
    val courseName = remember {
        mutableStateOf("")
    }

    val courseDuration = remember {
        mutableStateOf("")
    }

    val courseDescription = remember {
        mutableStateOf("")
    }

    // on below line creating a column
    // to display our retrieved image view.
    Column(
        // adding modifier for our column
        modifier = Modifier
            .fillMaxHeight()
            .fillMaxWidth()
            .background(Color.White),
        // on below line adding vertical and
        // horizontal alignment for column.
        verticalArrangement = Arrangement.Center, horizontalAlignment = Alignment.CenterHorizontally
    ) {


        TextField(
            // on below line we are specifying
            // value for our course name text field.
            value = courseName.value,

            // on below line we are adding on
            // value change for text field.
            onValueChange = { courseName.value = it },

            // on below line we are adding place holder
            // as text as "Enter your course name"
            placeholder = { Text(text = "Enter your course name") },

            // on below line we are adding modifier to it
            // and adding padding to it and filling max width
            modifier = Modifier
                .padding(16.dp)
                .fillMaxWidth(),

            // on below line we are adding text style
            // specifying color and font size to it.
            textStyle = TextStyle(color = Color.Black, fontSize = 15.sp),

            // on below line we are adding
            // single line to it.
            singleLine = true,
        )

        Spacer(modifier = Modifier.height(10.dp))

        TextField(
            // on below line we are specifying
            // value for our course duration text field.
            value = courseDuration.value,

            // on below line we are adding on
            // value change for text field.
            onValueChange = { courseDuration.value = it },

            // on below line we are adding place holder
            // as text as "Enter your course duration"
            placeholder = { Text(text = "Enter your course duration") },

            // on below line we are adding modifier to it
            // and adding padding to it and filling max width
            modifier = Modifier
                .padding(16.dp)
                .fillMaxWidth(),

            // on below line we are adding text style
            // specifying color and font size to it.
            textStyle = TextStyle(color = Color.Black, fontSize = 15.sp),

            // on below line we are adding
            // single line to it.
            singleLine = true,
        )

        Spacer(modifier = Modifier.height(10.dp))

        TextField(
            // on below line we are specifying
            // value for our course description text field.
            value = courseDescription.value,

            // on below line we are adding on
            // value change for text field.
            onValueChange = { courseDescription.value = it },

            // on below line we are adding place holder
            // as text as "Enter your course description"
            placeholder = { Text(text = "Enter your course description") },

            // on below line we are adding modifier to it
            // and adding padding to it and filling max width
            modifier = Modifier
                .padding(16.dp)
                .fillMaxWidth(),

            // on below line we are adding text style
            // specifying color and font size to it.
            textStyle = TextStyle(color = Color.Black, fontSize = 15.sp),

            // on below line we are adding
            // single line to it.
            singleLine = true,
        )

        Spacer(modifier = Modifier.height(10.dp))

        // on below line creating button to
        // add data to firebase firestore database.
        Button(
            onClick = {
                // on below line we are validating user input parameters.
                if (TextUtils.isEmpty(courseName.value.toString())) {
                    Toast.makeText(context, "Please enter course name", Toast.LENGTH_SHORT).show()
                } else if (TextUtils.isEmpty(courseDuration.value.toString())) {
                    Toast.makeText(context, "Please enter course Duration", Toast.LENGTH_SHORT)
                        .show()
                } else if (TextUtils.isEmpty(courseDescription.value.toString())) {
                    Toast.makeText(context, "Please enter course descritpion", Toast.LENGTH_SHORT)
                        .show()
                } else {
                    // on below line adding data to
                    // firebase firestore database.
                    addDataToFirebase(
                        courseName.value,
                        courseDuration.value,
                        courseDescription.value, context
                    )
                }
            },
            // on below line we are
            // adding modifier to our button.
            modifier = Modifier
                .fillMaxWidth()
                .padding(16.dp)
        ) {
            // on below line we are adding text for our button
            Text(text = "Add Data", modifier = Modifier.padding(8.dp))
        }
    }
}

fun addDataToFirebase(
    courseName: String,
    courseDuration: String,
    courseDescription: String,
    context: Context
) {
    // on below line creating an instance of firebase firestore.
    val db: FirebaseFirestore = FirebaseFirestore.getInstance()
    //creating a collection reference for our Firebase Firestore database.
    val dbCourses: CollectionReference = db.collection("Courses")
    //adding our data to our courses object class.
    val courses = Course(courseName, courseDescription, courseDuration)

    //below method is use to add data to Firebase Firestore.
    dbCourses.add(courses).addOnSuccessListener {
       // after the data addition is successful
       // we are displaying a success toast message.
        Toast.makeText(
            context,
            "Your Course has been added to Firebase Firestore",
            Toast.LENGTH_SHORT
        ).show()

    }.addOnFailureListener { e ->
        // this method is called when the data addition process is failed.
        // displaying a toast message when data addition is failed.
        Toast.makeText(context, "Fail to add course \n$e", Toast.LENGTH_SHORT).show()
    }

}