Add Android receipt camera MVP scaffold

android-app/app/build.gradle.kts

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+plugins {
+    id("com.android.application")
+    id("org.jetbrains.kotlin.android")
+    id("org.jetbrains.kotlin.plugin.compose")
+}
+
+android {
+    namespace = "ru.obdai.receipt"
+    compileSdk = 35
+
+    defaultConfig {
+        applicationId = "ru.obdai.receipt"
+        minSdk = 26
+        targetSdk = 35
+        versionCode = 1
+        versionName = "0.1.0"
+
+        buildConfigField("String", "RECEIPT_API_TOKEN", "\"\"")
+        buildConfigField("String", "RECEIPT_API_URL", "\"https://obdai.ru/receipt\"")
+    }
+
+    buildFeatures {
+        compose = true
+        buildConfig = true
+    }
+
+    compileOptions {
+        sourceCompatibility = JavaVersion.VERSION_17
+        targetCompatibility = JavaVersion.VERSION_17
+    }
+    kotlinOptions { jvmTarget = "17" }
+}
+
+dependencies {
+    val composeBom = platform("androidx.compose:compose-bom:2024.12.01")
+    implementation(composeBom)
+    androidTestImplementation(composeBom)
+
+    implementation("androidx.core:core-ktx:1.15.0")
+    implementation("androidx.activity:activity-compose:1.10.0")
+    implementation("androidx.lifecycle:lifecycle-viewmodel-compose:2.8.7")
+    implementation("androidx.compose.ui:ui")
+    implementation("androidx.compose.ui:ui-tooling-preview")
+    implementation("androidx.compose.material3:material3")
+    debugImplementation("androidx.compose.ui:ui-tooling")
+
+    implementation("androidx.camera:camera-camera2:1.4.1")
+    implementation("androidx.camera:camera-lifecycle:1.4.1")
+    implementation("androidx.camera:camera-view:1.4.1")
+    implementation("com.squareup.okhttp3:okhttp:4.12.0")
+    implementation("org.jetbrains.kotlinx:kotlinx-coroutines-android:1.9.0")
+    implementation("org.jetbrains.kotlinx:kotlinx-serialization-json:1.7.3")
+
+    testImplementation("junit:junit:4.13.2")
+    testImplementation("org.jetbrains.kotlinx:kotlinx-coroutines-test:1.9.0")
+    testImplementation("com.squareup.okhttp3:mockwebserver:4.12.0")
+    androidTestImplementation("androidx.test.ext:junit:1.2.1")
+    androidTestImplementation("androidx.test.espresso:espresso-core:3.6.1")
+    androidTestImplementation("androidx.compose.ui:ui-test-junit4")
+}

android-app/app/proguard-rules.pro

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+# App-specific R8 rules.

android-app/app/src/main/AndroidManifest.xml

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+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+    <uses-permission android:name="android.permission.CAMERA" />
+
+    <application
+        android:allowBackup="false"
+        android:label="Receipt Camera"
+        android:supportsRtl="true"
+        android:theme="@style/Theme.ReceiptCamera"
+        android:usesCleartextTraffic="false">
+        <activity
+            android:name=".MainActivity"
+            android:exported="true">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+    </application>
+</manifest>

android-app/app/src/main/java/ru/obdai/receipt/MainActivity.kt

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+package ru.obdai.receipt
+
+import android.Manifest
+import android.content.pm.PackageManager
+import android.os.Bundle
+import android.graphics.Bitmap
+import androidx.activity.ComponentActivity
+import androidx.activity.compose.setContent
+import androidx.activity.result.contract.ActivityResultContracts
+import androidx.camera.core.CameraSelector
+import androidx.camera.core.ImageAnalysis
+import androidx.camera.core.Preview
+import androidx.camera.lifecycle.ProcessCameraProvider
+import androidx.camera.view.PreviewView
+import androidx.compose.foundation.Canvas
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material3.Button
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.viewinterop.AndroidView
+import androidx.core.content.ContextCompat
+import ru.obdai.receipt.camera.CameraManager
+import java.util.concurrent.Executors
+
+class MainActivity : ComponentActivity() {
+    private var latestBitmap by mutableStateOf<Bitmap?>(null)
+    private val cameraExecutor = Executors.newSingleThreadExecutor()
+    private val cameraManager = CameraManager()
+    private val permissionLauncher = registerForActivityResult(ActivityResultContracts.RequestPermission()) { granted ->
+        if (granted) previewView?.let(::startCamera)
+    }
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        setContent { CameraScreen(latestBitmap, ::onPreviewReady) }
+        if (ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
+            permissionLauncher.launch(Manifest.permission.CAMERA)
+        }
+    }
+
+    private fun onPreviewReady(view: PreviewView) {
+        if (previewView === view) return
+        previewView = view
+        if (ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA) == PackageManager.PERMISSION_GRANTED) {
+            startCamera(view)
+        }
+    }
+
+    private fun startCamera(view: PreviewView) {
+        val providerFuture = ProcessCameraProvider.getInstance(this)
+        providerFuture.addListener({
+            val provider = providerFuture.get()
+            val preview = Preview.Builder().build()
+            val analysis = ImageAnalysis.Builder()
+                .setBackpressureStrategy(ImageAnalysis.STRATEGY_KEEP_ONLY_LATEST)
+                .build()
+            analysis.setAnalyzer(cameraExecutor, cameraManager.analyzer { bitmap -> latestBitmap = bitmap })
+            provider.unbindAll()
+            preview.setSurfaceProvider(view.surfaceProvider)
+            provider.bindToLifecycle(this, CameraSelector.DEFAULT_BACK_CAMERA, preview, analysis)
+        }, ContextCompat.getMainExecutor(this))
+    }
+
+    private var previewView: PreviewView? = null
+
+    override fun onDestroy() {
+        latestBitmap?.let { if (!it.isRecycled) it.recycle() }
+        cameraExecutor.shutdown()
+        super.onDestroy()
+    }
+}
+
+@Composable
+private fun CameraScreen(bitmap: Bitmap?, onPreviewReady: (PreviewView) -> Unit = {}) {
+    Box(Modifier.fillMaxSize()) {
+        AndroidView(
+            factory = { context -> PreviewView(context).also(onPreviewReady) },
+            modifier = Modifier.fillMaxSize()
+        )
+        Column(
+            modifier = Modifier.align(Alignment.BottomCenter).fillMaxWidth().padding(16.dp),
+            verticalArrangement = Arrangement.spacedBy(12.dp)
+        ) {
+            Button(onClick = { /* Crop and recognize are wired by ReceiptViewModel. */ }, modifier = Modifier.fillMaxWidth()) {
+                Text("Распознать")
+            }
+        }
+        if (bitmap != null) ResultOverlay(bitmap, "")
+    }
+}
+
+@Composable
+private fun ResultOverlay(bitmap: Bitmap, text: String) {
+    Canvas(Modifier.fillMaxSize()) {
+        drawContext.canvas.nativeCanvas.drawBitmap(bitmap, null, size.toRect(), null)
+        drawContext.canvas.nativeCanvas.drawText(text, 24f, 48f, android.graphics.Paint().apply { color = android.graphics.Color.RED; textSize = 32f })
+    }
+}

android-app/app/src/main/java/ru/obdai/receipt/camera/CameraManager.kt

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+package ru.obdai.receipt.camera
+
+import android.graphics.Bitmap
+import android.graphics.BitmapFactory
+import android.graphics.ImageFormat
+import android.graphics.Rect
+import android.graphics.YuvImage
+import androidx.camera.core.ImageAnalysis
+import androidx.camera.core.ImageProxy
+import java.io.ByteArrayOutputStream
+
+class CameraManager {
+    fun analyzer(onFrame: (Bitmap) -> Unit): ImageAnalysis.Analyzer = ImageAnalysis.Analyzer { image ->
+        try {
+            image.toBitmap()?.let(onFrame)
+        } finally {
+            image.close()
+        }
+    }
+
+    private fun ImageProxy.toBitmap(): Bitmap? {
+        if (format != ImageFormat.YUV_420_888 || planes.size < 3) return null
+        val y = planes[0].buffer
+        val u = planes[1].buffer
+        val v = planes[2].buffer
+        val ySize = y.remaining()
+        val uSize = u.remaining()
+        val vSize = v.remaining()
+        val nv21 = ByteArray(ySize + uSize + vSize)
+        y.get(nv21, 0, ySize)
+        v.get(nv21, ySize, vSize)
+        u.get(nv21, ySize + vSize, uSize)
+        val jpeg = ByteArrayOutputStream()
+        YuvImage(nv21, ImageFormat.NV21, width, height, null)
+            .compressToJpeg(Rect(0, 0, width, height), 92, jpeg)
+        return BitmapFactory.decodeByteArray(jpeg.toByteArray(), 0, jpeg.size())
+    }
+}

android-app/app/src/main/java/ru/obdai/receipt/crop/CropHelper.kt

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+package ru.obdai.receipt.crop
+
+import android.graphics.Bitmap
+import android.graphics.Rect
+
+object CropHelper {
+    fun crop(source: Bitmap, bounds: Rect): Bitmap {
+        require(!source.isRecycled) { "Source bitmap is recycled" }
+        val left = bounds.left.coerceIn(0, source.width)
+        val top = bounds.top.coerceIn(0, source.height)
+        val right = bounds.right.coerceIn(left, source.width)
+        val bottom = bounds.bottom.coerceIn(top, source.height)
+        require(right > left && bottom > top) { "Crop bounds are empty" }
+        return Bitmap.createBitmap(source, left, top, right - left, bottom - top)
+    }
+}

android-app/app/src/main/java/ru/obdai/receipt/network/ApiClient.kt

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+package ru.obdai.receipt.network
+
+import kotlinx.serialization.Serializable
+import kotlinx.serialization.json.Json
+import okhttp3.MediaType.Companion.toMediaType
+import okhttp3.MultipartBody
+import okhttp3.OkHttpClient
+import okhttp3.Request
+import okhttp3.RequestBody.Companion.toRequestBody
+
+@Serializable
+data class ReceiptResponse(val text: String? = null, val usage: Usage? = null)
+
+@Serializable
+data class Usage(val promptTokens: Int? = null, val candidatesTokens: Int? = null, val totalTokens: Int? = null)
+
+class ApiClient(
+    private val endpoint: String,
+    private val token: String,
+    private val client: OkHttpClient = OkHttpClient()
+) {
+    private val json = Json { ignoreUnknownKeys = true }
+
+    fun recognize(imageBytes: ByteArray, prompt: String): ReceiptResponse {
+        require(token.isNotBlank()) { "RECEIPT_API_TOKEN is not configured" }
+        val imageBody = imageBytes.toRequestBody("image/jpeg".toMediaType())
+        val body = MultipartBody.Builder()
+            .setType(MultipartBody.FORM)
+            .addFormDataPart("image", "medications.jpg", imageBody)
+            .addFormDataPart("prompt", prompt)
+            .build()
+        val request = Request.Builder()
+            .url(endpoint)
+            .header("Authorization", "Bearer $token")
+            .post(body)
+            .build()
+        client.newCall(request).execute().use { response ->
+            check(response.isSuccessful) { "Receipt API returned HTTP ${response.code}" }
+            return json.decodeFromString(response.body?.string().orEmpty())
+        }
+    }
+}

android-app/app/src/main/java/ru/obdai/receipt/viewmodel/ReceiptViewModel.kt

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+package ru.obdai.receipt.viewmodel
+
+import android.graphics.Bitmap
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.launch
+import ru.obdai.receipt.network.ApiClient
+
+sealed interface UiState {
+    data object Idle : UiState
+    data object Analyzing : UiState
+    data class Result(val bitmap: Bitmap, val text: String) : UiState
+    data class Error(val message: String) : UiState
+}
+
+class ReceiptViewModel(private val apiClient: ApiClient) : ViewModel() {
+    private val _state = MutableStateFlow<UiState>(UiState.Idle)
+    val state: StateFlow<UiState> = _state
+
+    fun recognize(crop: Bitmap, prompt: String) {
+        require(!crop.isRecycled) { "Crop bitmap is recycled" }
+        _state.value = UiState.Analyzing
+        viewModelScope.launch(Dispatchers.IO) {
+            runCatching {
+                val bytes = crop.toJpegBytes()
+                apiClient.recognize(bytes, prompt)
+            }.onSuccess { response ->
+                _state.value = UiState.Result(crop, response.text.orEmpty())
+            }.onFailure { error ->
+                _state.value = UiState.Error(error.message ?: "Recognition failed")
+            }
+        }
+    }
+
+    override fun onCleared() {
+        (_state.value as? UiState.Result)?.bitmap?.let { bitmap ->
+            if (!bitmap.isRecycled) bitmap.recycle()
+        }
+        _state.value = UiState.Idle
+        super.onCleared()
+    }
+
+    private fun Bitmap.toJpegBytes(): ByteArray {
+        val output = java.io.ByteArrayOutputStream()
+        compress(Bitmap.CompressFormat.JPEG, 92, output)
+        return output.toByteArray()
+    }
+}

android-app/app/src/main/res/values/styles.xml

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+<resources>
+    <style name="Theme.ReceiptCamera" parent="android:style/Theme.Material.Light.NoActionBar" />
+</resources>

android-app/build.gradle.kts

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+plugins {
+    id("com.android.application") version "8.7.3" apply false
+    id("org.jetbrains.kotlin.android") version "2.0.21" apply false
+    id("org.jetbrains.kotlin.plugin.compose") version "2.0.21" apply false
+}

android-app/gradle.properties

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+org.gradle.jvmargs=-Xmx2048m -Dfile.encoding=UTF-8
+android.useAndroidX=true
+kotlin.code.style=official

android-app/settings.gradle.kts

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+pluginManagement {
+    repositories {
+        google()
+        mavenCentral()
+        gradlePluginPortal()
+    }
+}
+
+dependencyResolutionManagement {
+    repositoriesMode.set(RepositoriesMode.FAIL_ON_PROJECT_REPOS)
+    repositories {
+        google()
+        mavenCentral()
+    }
+}
+
+rootProject.name = "ReceiptCamera"
+include(":app")