amethyst/app/src/main/java/com/vitorpamplona/amethyst/ui/actions/UploadFromGallery.kt

package com.vitorpamplona.amethyst.ui.navigation

import android.net.Uri
import androidx.activity.compose.rememberLauncherForActivityResult
import androidx.activity.result.contract.ActivityResultContracts
import androidx.compose.foundation.layout.Box
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.padding
import androidx.compose.material.Button
import androidx.compose.material.Text
import androidx.compose.runtime.Composable
import androidx.compose.runtime.SideEffect
import androidx.compose.runtime.getValue
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.runtime.setValue
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.unit.dp
import com.google.accompanist.permissions.ExperimentalPermissionsApi
import com.google.accompanist.permissions.isGranted
import com.google.accompanist.permissions.rememberPermissionState
import com.google.accompanist.permissions.shouldShowRationale

@OptIn(ExperimentalPermissionsApi::class)
@Composable
fun UploadFromGallery(onImageChosen: (Uri) -> Unit) {
    val cameraPermissionState = rememberPermissionState(
        android.Manifest.permission.READ_MEDIA_IMAGES
    )

    if (cameraPermissionState.status.isGranted) {
        var showGallerySelect by remember { mutableStateOf(false) }
        if (showGallerySelect) {
            GallerySelect(
                onImageUri = { uri ->
                    showGallerySelect = false
                    if (uri != null)
                        onImageChosen(uri)
                }
            )
        } else {
            Box() {
                Button(
                    modifier = Modifier
                        .align(Alignment.TopCenter)
                        .padding(4.dp),
                    onClick = {
                        showGallerySelect = true
                    }
                ) {
                    Text("Add Image from Gallery")
                }
            }
        }
    } else {
        Column {
            val textToShow = if (cameraPermissionState.status.shouldShowRationale) {
                // If the user has denied the permission but the rationale can be shown,
                // then gently explain why the app requires this permission
                "Grant access to quickly upload pictures before posting"
            } else {
                // If it's the first time the user lands on this feature, or the user
                // doesn't want to be asked again for this permission, explain that the
                // permission is required
                "Grant access to quickly upload pictures before posting"
            }
            Text(textToShow)
            Button(onClick = { cameraPermissionState.launchPermissionRequest() }) {
                Text("Request permission")
            }
        }
    }
}


@Composable
fun GallerySelect(
    onImageUri: (Uri?) -> Unit = { }
) {
    val launcher = rememberLauncherForActivityResult(
        contract = ActivityResultContracts.GetContent(),
        onResult = { uri: Uri? ->
            onImageUri(uri)
        }
    )

    @Composable
    fun LaunchGallery() {
        SideEffect {
            launcher.launch("image/*")
        }
    }

    LaunchGallery()
}