ShowkaseBrowserActivity.kt

package com.airbnb.android.showkase.ui

import android.content.Context
import android.content.Intent
import android.os.Bundle
import androidx.activity.compose.setContent
import androidx.appcompat.app.AppCompatActivity
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import com.airbnb.android.showkase.exceptions.ShowkaseException
import com.airbnb.android.showkase.models.ShowkaseBrowserScreenMetadata
import com.airbnb.android.showkase.models.ShowkaseProvider
import com.airbnb.android.showkase.models.ShowkaseElementsMetadata

/**
 * The activity that's responsible for showing all the UI elements that were annotated
 * with the Showkase related annotations.
 */
class ShowkaseBrowserActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        val classKey = intent.extras?.getString(SHOWKASE_ROOT_MODULE_KEY) ?: throw ShowkaseException(
            "Missing key in bundle. Please start this activity by using the intent returned by " +
                    "the ShowkaseBrowserActivity.getIntent() method."
        )
        setContent {
            val (
                groupedComponentsList,
                groupedColorsList,
                groupedTypographyList
            ) = getShowkaseProviderElements(classKey)
            
            val showkaseBrowserScreenMetadata = 
                remember { mutableStateOf(ShowkaseBrowserScreenMetadata()) }
            when {
                groupedComponentsList.isNotEmpty() || groupedColorsList.isNotEmpty() || 
                        groupedTypographyList.isNotEmpty() -> {
                    ShowkaseBrowserApp(
                        groupedComponentsList.groupBy { it.group }, 
                        groupedColorsList.groupBy { it.colorGroup }, 
                        groupedTypographyList.groupBy { it.typographyGroup },
                        showkaseBrowserScreenMetadata)
                }
                else -> {
                    ShowkaseErrorScreen(
                        errorText = "There were no elements that were annotated with either " +
                                "@ShowkaseComposable, @ShowkaseTypography or @ShowkaseColor. If " +
                                "you think this is a mistake, file an issue at " +
                                "https://github.com/airbnb/Showkase/issues"
                    )
                }
            }
        }
    }

    private fun getShowkaseProviderElements(
        classKey: String
    ): ShowkaseElementsMetadata {
        return try {
            val showkaseComponentProvider =
                Class.forName("$classKey$AUTOGEN_CLASS_NAME").getDeclaredConstructor().newInstance()
            
            val showkaseMetadata = (showkaseComponentProvider as ShowkaseProvider).metadata()

            ShowkaseElementsMetadata(
                componentList = showkaseMetadata.componentList,
                colorList = showkaseMetadata.colorList,
                typographyList = showkaseMetadata.typographyList
            )
        } catch (exception: ClassNotFoundException) {
            ShowkaseElementsMetadata()
        }
    }

    companion object {
        private const val SHOWKASE_ROOT_MODULE_KEY = "SHOWKASE_ROOT_MODULE"
        private const val AUTOGEN_CLASS_NAME = "Codegen"

        /**
         * Returns the intent that the users of this library need to use for starting the
         * Showkase browser activity. Please make sure to use this instead of starting the
         * activity directly as it sets the right value in the bundle in order for the activity
         * to start correctly.
         * 
         * @param context Android context
         * @param rootModuleCanonicalName The canonical name of the implementation of 
         * ShowkaseRootModule.
         */
        fun getIntent(context: Context, rootModuleCanonicalName: String) =
            Intent(context, ShowkaseBrowserActivity::class.java).apply {
                putExtra(SHOWKASE_ROOT_MODULE_KEY, rootModuleCanonicalName)
            }
    }
}