How to Solve Captcha in Browser4 with CapSolver Integration

<dependencies>
    <!-- Browser4/PulsarRPA -->
    <dependency>
        <groupId>ai.platon.pulsar</groupId>
        <artifactId>pulsar-boot</artifactId>
        <version>2.2.0</version>
    </dependency>

    <!-- HTTP Client for CapSolver -->
    <dependency>
        <groupId>com.squareup.okhttp3</groupId>
        <artifactId>okhttp</artifactId>
        <version>4.12.0</version>
    </dependency>

    <!-- JSON Parsing -->
    <dependency>
        <groupId>com.google.code.gson</groupId>
        <artifactId>gson</artifactId>
        <version>2.10.1</version>
    </dependency>

    <!-- Kotlin Coroutines -->
    <dependency>
        <groupId>org.jetbrains.kotlinx</groupId>
        <artifactId>kotlinx-coroutines-core</artifactId>
        <version>1.8.0</version>
    </dependency>
</dependencies>

dependencies {
    implementation("ai.platon.pulsar:pulsar-boot:2.2.0")
    implementation("com.squareup.okhttp3:okhttp:4.12.0")
    implementation("com.google.code.gson:gson:2.10.1")
    implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core:1.8.0")
}

# CapSolver Configuration
CAPSOLVER_API_KEY=your_capsolver_api_key

# LLM Configuration (optional, for AI extraction)
OPENROUTER_API_KEY=your_openrouter_api_key

# Proxy Configuration (optional)
PROXY_ROTATION_URL=your_proxy_url

import com.google.gson.Gson
import com.google.gson.JsonObject
import okhttp3.MediaType.Companion.toMediaType
import okhttp3.OkHttpClient
import okhttp3.Request
import okhttp3.RequestBody.Companion.toRequestBody
import kotlinx.coroutines.delay
import java.util.concurrent.TimeUnit

data class TaskResult(
    val gRecaptchaResponse: String? = null,
    val token: String? = null,
    val cookies: List<Map<String, String>>? = null,
    val userAgent: String? = null
)

class CapSolverService(private val apiKey: String) {
    private val client = OkHttpClient.Builder()
        .connectTimeout(30, TimeUnit.SECONDS)
        .readTimeout(30, TimeUnit.SECONDS)
        .build()

    private val gson = Gson()
    private val baseUrl = "https://api.capsolver.com"
    private val jsonMediaType = "application/json".toMediaType()

    private suspend fun createTask(taskData: Map<String, Any>): String {
        val payload = mapOf(
            "clientKey" to apiKey,
            "task" to taskData
        )

        val request = Request.Builder()
            .url("$baseUrl/createTask")
            .post(gson.toJson(payload).toRequestBody(jsonMediaType))
            .build()

        val response = client.newCall(request).execute()
        val result = gson.fromJson(response.body?.string(), JsonObject::class.java)

        if (result.get("errorId").asInt != 0) {
            throw Exception("CapSolver error: ${result.get("errorDescription").asString}")
        }

        return result.get("taskId").asString
    }

    private suspend fun getTaskResult(taskId: String, maxAttempts: Int = 60): TaskResult {
        val payload = mapOf(
            "clientKey" to apiKey,
            "taskId" to taskId
        )

        repeat(maxAttempts) {
            delay(2000)

            val request = Request.Builder()
                .url("$baseUrl/getTaskResult")
                .post(gson.toJson(payload).toRequestBody(jsonMediaType))
                .build()

            val response = client.newCall(request).execute()
            val result = gson.fromJson(response.body?.string(), JsonObject::class.java)

            when (result.get("status")?.asString) {
                "ready" -> {
                    val solution = result.getAsJsonObject("solution")
                    return TaskResult(
                        gRecaptchaResponse = solution.get("gRecaptchaResponse")?.asString,
                        token = solution.get("token")?.asString,
                        userAgent = solution.get("userAgent")?.asString
                    )
                }
                "failed" -> throw Exception("Task failed: ${result.get("errorDescription")?.asString}")
            }
        }

        throw Exception("Timeout waiting for CAPTCHA solution")
    }

    suspend fun solveReCaptchaV2(websiteUrl: String, websiteKey: String): String {
        val taskId = createTask(mapOf(
            "type" to "ReCaptchaV2TaskProxyLess",
            "websiteURL" to websiteUrl,
            "websiteKey" to websiteKey
        ))

        val result = getTaskResult(taskId)
        return result.gRecaptchaResponse ?: throw Exception("No gRecaptchaResponse in solution")
    }

    suspend fun solveReCaptchaV3(
        websiteUrl: String,
        websiteKey: String,
        pageAction: String = "submit"
    ): String {
        val taskId = createTask(mapOf(
            "type" to "ReCaptchaV3TaskProxyLess",
            "websiteURL" to websiteUrl,
            "websiteKey" to websiteKey,
            "pageAction" to pageAction
        ))

        val result = getTaskResult(taskId)
        return result.gRecaptchaResponse ?: throw Exception("No gRecaptchaResponse in solution")
    }

    suspend fun solveTurnstile(
        websiteUrl: String,
        websiteKey: String,
        action: String? = null,
        cdata: String? = null
    ): String {
        val taskData = mutableMapOf(
            "type" to "AntiTurnstileTaskProxyLess",
            "websiteURL" to websiteUrl,
            "websiteKey" to websiteKey
        )

        // Add optional metadata
        if (action != null || cdata != null) {
            val metadata = mutableMapOf<String, String>()
            action?.let { metadata["action"] = it }
            cdata?.let { metadata["cdata"] = it }
            taskData["metadata"] = metadata
        }

        val taskId = createTask(taskData)
        val result = getTaskResult(taskId)
        return result.token ?: throw Exception("No token in solution")
    }

    suspend fun checkBalance(): Double {
        val payload = mapOf("clientKey" to apiKey)

        val request = Request.Builder()
            .url("$baseUrl/getBalance")
            .post(gson.toJson(payload).toRequestBody(jsonMediaType))
            .build()

        val response = client.newCall(request).execute()
        val result = gson.fromJson(response.body?.string(), JsonObject::class.java)

        return result.get("balance")?.asDouble ?: 0.0
    }
}

import ai.platon.pulsar.context.PulsarContexts
import ai.platon.pulsar.skeleton.session.PulsarSession
import kotlinx.coroutines.runBlocking

class ReCaptchaV2Extractor(
    private val capSolver: CapSolverService
) {
    suspend fun extractWithCaptcha(targetUrl: String, siteKey: String): Map<String, Any?> {
        println("Solving reCAPTCHA v2...")

        // Solve the CAPTCHA first
        val token = capSolver.solveReCaptchaV2(targetUrl, siteKey)
        println("CAPTCHA solved, token length: ${token.length}")

        // Create session and open the page
        val session = PulsarContexts.createSession()
        val page = session.open(targetUrl)
        val driver = session.getOrCreateBoundDriver()

        // Inject the token into the hidden textarea using value property (safe)
        driver?.evaluate("""
            (function() {
                var el = document.querySelector('#g-recaptcha-response');
                if (el) el.value = arguments[0];
            })('$token');
        """)

        // Submit the form
        driver?.evaluate("document.querySelector('form').submit();")

        // Wait for navigation
        Thread.sleep(3000)

        // Extract data from the result page
        val document = session.parse(page)

        mapOf(
            "title" to document.selectFirstTextOrNull("h1"),
            "content" to document.selectFirstTextOrNull(".content"),
            "success" to (document.body().text().contains("success", ignoreCase = true))
        )
    }
}

fun main() = runBlocking {
    val apiKey = System.getenv("CAPSOLVER_API_KEY") ?: "your_api_key"
    val capSolver = CapSolverService(apiKey)

    val extractor = ReCaptchaV2Extractor(capSolver)

    val result = extractor.extractWithCaptcha(
        targetUrl = "https://example.com/protected-page",
        siteKey = "6LcxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxABC"
    )

    println("Extraction result: $result")
}

class ReCaptchaV3Extractor(
    private val capSolver: CapSolverService
) {
    suspend fun extractWithCaptchaV3(
        targetUrl: String,
        siteKey: String,
        action: String = "submit"
    ): Map<String, Any?> {
        println("Solving reCAPTCHA v3 with action: $action")

        // Solve reCAPTCHA v3 with custom page action
        val token = capSolver.solveReCaptchaV3(
            websiteUrl = targetUrl,
            websiteKey = siteKey,
            pageAction = action
        )

        println("Token obtained successfully")

        // Create session and open the page
        val session = PulsarContexts.createSession()
        val page = session.open(targetUrl)
        val driver = session.getOrCreateBoundDriver()

        // Inject token into hidden input (using safe value assignment)
        driver?.evaluate("""
            (function(tokenValue) {
                var input = document.querySelector('input[name="g-recaptcha-response"]');
                if (input) {
                    input.value = tokenValue;
                } else {
                    var hidden = document.createElement('input');
                    hidden.type = 'hidden';
                    hidden.name = 'g-recaptcha-response';
                    hidden.value = tokenValue;
                    var form = document.querySelector('form');
                    if (form) form.appendChild(hidden);
                }
            })('$token');
        """)

        // Click submit button
        driver?.evaluate("document.querySelector('#submit-btn').click();")

        Thread.sleep(3000)

        val document = session.parse(page)

        mapOf(
            "result" to document.selectFirstTextOrNull(".result-data"),
            "status" to "success"
        )
    }
}

class TurnstileExtractor(
    private val capSolver: CapSolverService
) {
    suspend fun extractWithTurnstile(targetUrl: String, siteKey: String): Map<String, Any?> {
        println("Solving Cloudflare Turnstile...")

        // Solve with optional metadata (action and cdata)
        val token = capSolver.solveTurnstile(
            targetUrl,
            siteKey,
            action = "login",  // optional
            cdata = "0000-1111-2222-3333-example"  // optional
        )
        println("Turnstile solved!")

        val session = PulsarContexts.createSession()
        val page = session.open(targetUrl)
        val driver = session.getOrCreateBoundDriver()

        // Inject Turnstile token (using safe value assignment)
        driver?.evaluate("""
            (function(tokenValue) {
                var input = document.querySelector('input[name="cf-turnstile-response"]');
                if (input) input.value = tokenValue;
            })('$token');
        """)

        // Submit
        driver?.evaluate("document.querySelector('form').submit();")

        Thread.sleep(3000)

        val document = session.parse(page)

        mapOf(
            "title" to document.selectFirstTextOrNull("title"),
            "content" to document.selectFirstTextOrNull("body")?.take(500)
        )
    }
}

class XSqlCaptchaExtractor(
    private val capSolver: CapSolverService
) {
    suspend fun extractProductsWithCaptcha(
        targetUrl: String,
        siteKey: String
    ): List<Map<String, Any?>> {
        // Pre-solve CAPTCHA
        val token = capSolver.solveReCaptchaV2(targetUrl, siteKey)

        // Create session and establish authenticated session
        val session = PulsarContexts.createSession()
        val page = session.open(targetUrl)
        val driver = session.getOrCreateBoundDriver()

        driver?.evaluate("""
            (function(tokenValue) {
                var el = document.querySelector('#g-recaptcha-response');
                if (el) el.value = tokenValue;
                document.querySelector('form').submit();
            })('$token');
        """)

        Thread.sleep(3000)

        // Now parse the page and extract product data
        val document = session.parse(page)

        // Extract product data using built-in session methods
        val products = mutableListOf<Map<String, Any?>>()
        val productElements = document.select(".product-item")

        for ((index, element) in productElements.withIndex()) {
            if (index >= 50) break // LIMIT 50
            products.add(mapOf(
                "name" to element.selectFirstTextOrNull(".product-name"),
                "price" to element.selectFirstTextOrNull(".price")?.let {
                    """(\d+\.?\d*)""".toRegex().find(it)?.groupValues?.get(1)?.toDoubleOrNull() ?: 0.0
                },
                "rating" to element.selectFirstTextOrNull(".rating")
            ))
        }

        return products.map { row ->
            mapOf(
                "name" to row["name"],
                "price" to row["price"],
                "rating" to row["rating"],
                "image_url" to row["image_url"]
            )
        }
    }
}

import okhttp3.Cookie
import okhttp3.CookieJar
import okhttp3.HttpUrl

class PreAuthenticator(
    private val capSolver: CapSolverService
) {
    data class AuthSession(
        val cookies: Map<String, String>,
        val userAgent: String?
    )

    suspend fun authenticateWithCaptcha(
        loginUrl: String,
        siteKey: String
    ): AuthSession {
        // Solve CAPTCHA
        val captchaToken = capSolver.solveReCaptchaV2(loginUrl, siteKey)

        // Submit CAPTCHA to get session cookies
        val client = OkHttpClient.Builder()
            .cookieJar(object : CookieJar {
                private val cookies = mutableListOf<Cookie>()

                override fun saveFromResponse(url: HttpUrl, cookieList: List<Cookie>) {
                    cookies.addAll(cookieList)
                }

                override fun loadForRequest(url: HttpUrl): List<Cookie> = cookies
            })
            .build()

        val formBody = okhttp3.FormBody.Builder()
            .add("g-recaptcha-response", captchaToken)
            .build()

        val request = Request.Builder()
            .url(loginUrl)
            .post(formBody)
            .build()

        val response = client.newCall(request).execute()

        // Extract cookies from response
        val responseCookies = response.headers("Set-Cookie")
            .associate { cookie ->
                val parts = cookie.split(";")[0].split("=", limit = 2)
                parts[0] to (parts.getOrNull(1) ?: "")
            }

        return AuthSession(
            cookies = responseCookies,
            userAgent = response.request.header("User-Agent")
        )
    }
}

class AuthenticatedExtractor(
    private val preAuth: PreAuthenticator,
    private val capSolver: CapSolverService
) {
    suspend fun extractWithAuth(
        loginUrl: String,
        targetUrl: String,
        siteKey: String
    ): Map<String, Any?> {
        // Pre-authenticate
        val authSession = preAuth.authenticateWithCaptcha(loginUrl, siteKey)
        println("Session established with ${authSession.cookies.size} cookies")

        // Create Browser4 session
        val session = PulsarContexts.createSession()

        // Configure session with cookies
        val cookieScript = authSession.cookies.entries.joinToString(";") { (k, v) ->
            "$k=$v"
        }

        val page = session.open(targetUrl)
        val driver = session.getOrCreateBoundDriver()

        // Set cookies
        driver?.evaluate("document.cookie = '$cookieScript';")

        // Reload with authenticated session
        driver?.evaluate("location.reload();")
        Thread.sleep(2000)

        // Extract data
        val document = session.parse(page)

        return mapOf(
            "authenticated" to true,
            "content" to document.selectFirstTextOrNull(".protected-content"),
            "userData" to document.selectFirstTextOrNull(".user-profile")
        )
    }
}

import com.google.gson.Gson
import com.google.gson.JsonObject
import okhttp3.MediaType.Companion.toMediaType
import okhttp3.OkHttpClient
import okhttp3.Request
import okhttp3.RequestBody.Companion.toRequestBody
import java.util.concurrent.TimeUnit

data class ChatMessage(val role: String, val content: String)
data class ChatCompletion(val content: String, val model: String, val usage: TokenUsage)
data class TokenUsage(val promptTokens: Int, val completionTokens: Int, val totalTokens: Int)

class OpenRouterService(private val apiKey: String) {
    private val client = OkHttpClient.Builder()
        .connectTimeout(60, TimeUnit.SECONDS)
        .readTimeout(60, TimeUnit.SECONDS)
        .build()

    private val gson = Gson()
    private val baseUrl = "https://openrouter.ai/api/v1"
    private val jsonMediaType = "application/json".toMediaType()

    fun chat(
        messages: List<ChatMessage>,
        model: String = "openai/gpt-4o-mini"
    ): ChatCompletion {
        val payload = mapOf(
            "model" to model,
            "messages" to messages.map { mapOf("role" to it.role, "content" to it.content) }
        )

        val request = Request.Builder()
            .url("$baseUrl/chat/completions")
            .header("Authorization", "Bearer $apiKey")
            .post(gson.toJson(payload).toRequestBody(jsonMediaType))
            .build()

        val response = client.newCall(request).execute()
        val result = gson.fromJson(response.body?.string(), JsonObject::class.java)

        val choice = result.getAsJsonArray("choices")?.get(0)?.asJsonObject
        val content = choice?.getAsJsonObject("message")?.get("content")?.asString ?: ""

        val usage = result.getAsJsonObject("usage")

        return ChatCompletion(
            content = content,
            model = result.get("model")?.asString ?: model,
            usage = TokenUsage(
                promptTokens = usage?.get("prompt_tokens")?.asInt ?: 0,
                completionTokens = usage?.get("completion_tokens")?.asInt ?: 0,
                totalTokens = usage?.get("total_tokens")?.asInt ?: 0
            )
        )
    }

    fun extractStructuredData(html: String, schema: String): String {
        val prompt = """
            Extract the following data from this HTML content.
            Return ONLY valid JSON matching this schema: $schema

            HTML:
            ${html.take(4000)}
        """.trimIndent()

        return chat(listOf(ChatMessage("user", prompt))).content
    }

    fun listModels(): List<String> {
        val request = Request.Builder()
            .url("$baseUrl/models")
            .header("Authorization", "Bearer $apiKey")
            .build()

        val response = client.newCall(request).execute()
        val result = gson.fromJson(response.body?.string(), JsonObject::class.java)

        return result.getAsJsonArray("data")?.mapNotNull {
            it.asJsonObject.get("id")?.asString
        } ?: emptyList()
    }
}

class SmartExtractor(
    private val capSolver: CapSolverService,
    private val openRouter: OpenRouterService
) {
    suspend fun extractWithAI(
        targetUrl: String,
        siteKey: String?,
        extractionPrompt: String
    ): Map<String, Any?> {
        // Step 1: Solve CAPTCHA if needed
        val captchaToken = siteKey?.let {
            println("Solving CAPTCHA...")
            capSolver.solveReCaptchaV2(targetUrl, it)
        }

        // Step 2: Create session and open page
        val session = PulsarContexts.createSession()
        val page = session.open(targetUrl)
        val driver = session.getOrCreateBoundDriver()

        captchaToken?.let { token ->
            driver?.evaluate("""
                (function(tokenValue) {
                    var el = document.querySelector('#g-recaptcha-response');
                    if (el) el.value = tokenValue;
                    var form = document.querySelector('form');
                    if (form) form.submit();
                })('$token');
            """)
            Thread.sleep(3000)
        }

        // Step 3: Extract page content
        val document = session.parse(page)
        val pageContent = document.body().text().take(8000)

        // Step 4: Use LLM to extract structured data
        val llmResponse = openRouter.chat(listOf(
            ChatMessage("system", "You are a data extraction assistant. Extract structured data from web pages."),
            ChatMessage("user", """
                $extractionPrompt

                Page content:
                $pageContent
            """.trimIndent())
        ))

        println("LLM used ${llmResponse.usage.totalTokens} tokens")

        return mapOf(
            "url" to targetUrl,
            "captchaSolved" to (captchaToken != null),
            "extractedData" to llmResponse.content,
            "tokensUsed" to llmResponse.usage.totalTokens
        )
    }
}

// Usage
fun main() = runBlocking {
    val capSolver = CapSolverService(System.getenv("CAPSOLVER_API_KEY")!!)
    val openRouter = OpenRouterService(System.getenv("OPENROUTER_API_KEY")!!)

    val extractor = SmartExtractor(capSolver, openRouter)

    val result = extractor.extractWithAI(
        targetUrl = "https://example.com/products",
        siteKey = "6LcxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxABC",
        extractionPrompt = """
            Extract all products with:
            - name
            - price (as number)
            - availability (in_stock/out_of_stock)
            - rating (1-5)
            Return as JSON array.
        """.trimIndent()
    )

    println("Extraction result: ${result["extractedData"]}")
}

class AdaptiveExtractor(
    private val capSolver: CapSolverService,
    private val openRouter: OpenRouterService
) {
    suspend fun extractWithAdaptiveSelectors(
        targetUrl: String,
        siteKey: String?,
        dataFields: List<String>
    ): Map<String, Any?> {
        // Solve CAPTCHA first
        val token = siteKey?.let { capSolver.solveReCaptchaV2(targetUrl, it) }

        val session = PulsarContexts.createSession()
        val page = session.open(targetUrl)
        val driver = session.getOrCreateBoundDriver()

        token?.let { t ->
            driver?.evaluate("""
                (function(tokenValue) {
                    var el = document.querySelector('#g-recaptcha-response');
                    if (el) el.value = tokenValue;
                })('$t');
            """)
        }

        // Get page HTML structure
        val htmlSample = driver?.evaluate("document.body.innerHTML")?.toString()?.take(5000) ?: ""

        // Ask LLM to generate selectors
        val selectorPrompt = """
            Analyze this HTML and provide CSS selectors for these fields: ${dataFields.joinToString(", ")}

            HTML sample:
            $htmlSample

            Return JSON like: {"fieldName": "css-selector", ...}
        """.trimIndent()

        val selectorsJson = openRouter.chat(listOf(ChatMessage("user", selectorPrompt))).content
        val selectors = Gson().fromJson(selectorsJson, Map::class.java) as Map<String, String>

        // Extract using generated selectors
        val document = session.parse(page)
        val extractedData = selectors.mapValues { (_, selector) ->
            document.selectFirstTextOrNull(selector)
        }

        return mapOf(
            "url" to targetUrl,
            "selectors" to selectors,
            "data" to extractedData
        )
    }
}

import kotlinx.coroutines.*
import kotlinx.coroutines.channels.Channel

data class ExtractionJob(
    val url: String,
    val siteKey: String?
)

data class ExtractionResult(
    val url: String,
    val data: Map<String, Any?>?,
    val captchaSolved: Boolean,
    val error: String?,
    val duration: Long
)

class ParallelExtractor(
    private val capSolver: CapSolverService,
    private val concurrency: Int = 5
) {
    suspend fun extractAll(jobs: List<ExtractionJob>): List<ExtractionResult> = coroutineScope {
        val channel = Channel<ExtractionJob>(Channel.UNLIMITED)
        val results = mutableListOf<ExtractionResult>()

        // Send all jobs to channel
        jobs.forEach { channel.send(it) }
        channel.close()

        // Process with limited concurrency
        val workers = (1..concurrency).map { workerId ->
            async {
                val workerResults = mutableListOf<ExtractionResult>()
                // Each worker creates its own session for thread safety
                val workerSession = PulsarContexts.createSession()

                for (job in channel) {
                    val startTime = System.currentTimeMillis()
                    var captchaSolved = false

                    try {
                        // Solve CAPTCHA if site key provided
                        val token = job.siteKey?.let {
                            captchaSolved = true
                            capSolver.solveReCaptchaV2(job.url, it)
                        }

                        // Extract data
                        val page = workerSession.open(job.url)

                        token?.let { t ->
                            val driver = workerSession.getOrCreateBoundDriver()
                            driver?.evaluate("""
                                (function(tokenValue) {
                                    var el = document.querySelector('#g-recaptcha-response');
                                    if (el) el.value = tokenValue;
                                })('$t');
                            """)
                        }

                        val document = workerSession.parse(page)

                        workerResults.add(ExtractionResult(
                            url = job.url,
                            data = mapOf(
                                "title" to document.selectFirstTextOrNull("title"),
                                "h1" to document.selectFirstTextOrNull("h1")
                            ),
                            captchaSolved = captchaSolved,
                            error = null,
                            duration = System.currentTimeMillis() - startTime
                        ))
                    } catch (e: Exception) {
                        workerResults.add(ExtractionResult(
                            url = job.url,
                            data = null,
                            captchaSolved = captchaSolved,
                            error = e.message,
                            duration = System.currentTimeMillis() - startTime
                        ))
                    }
                }

                workerResults
            }
        }

        workers.awaitAll().flatten()
    }
}

// Usage
fun main() = runBlocking {
    val capSolver = CapSolverService(System.getenv("CAPSOLVER_API_KEY")!!)

    val extractor = ParallelExtractor(capSolver, concurrency = 5)

    val jobs = listOf(
        ExtractionJob("https://site1.com/data", "6Lc..."),
        ExtractionJob("https://site2.com/data", null),
        ExtractionJob("https://site3.com/data", "6Lc..."),
    )

    val results = extractor.extractAll(jobs)

    val solved = results.count { it.captchaSolved }
    println("Completed ${results.size} extractions, solved $solved CAPTCHAs")

    results.forEach { r ->
        println("${r.url}: ${r.duration}ms - ${r.error ?: "success"}")
    }
}

suspend fun <T> withRetry(
    maxRetries: Int = 3,
    initialDelay: Long = 1000,
    block: suspend () -> T
): T {
    var lastException: Exception? = null

    repeat(maxRetries) { attempt ->
        try {
            return block()
        } catch (e: Exception) {
            lastException = e
            println("Attempt ${attempt + 1} failed: ${e.message}")
            delay(initialDelay * (attempt + 1))
        }
    }

    throw lastException ?: Exception("Max retries exceeded")
}

// Usage
val token = withRetry(maxRetries = 3) {
    capSolver.solveReCaptchaV2(url, siteKey)
}

suspend fun ensureSufficientBalance(
    capSolver: CapSolverService,
    minBalance: Double = 1.0
) {
    val balance = capSolver.checkBalance()

    if (balance < minBalance) {
        throw Exception("Insufficient CapSolver balance: $${"%.2f".format(balance)}. Please recharge.")
    }

    println("CapSolver balance: $${"%.2f".format(balance)}")
}

class TokenCache(private val ttlMs: Long = 90_000) {
    private data class CachedToken(val token: String, val timestamp: Long)

    private val cache = mutableMapOf<String, CachedToken>()

    private fun getKey(domain: String, siteKey: String) = "$domain:$siteKey"

    fun get(domain: String, siteKey: String): String? {
        val key = getKey(domain, siteKey)
        val cached = cache[key] ?: return null

        if (System.currentTimeMillis() - cached.timestamp > ttlMs) {
            cache.remove(key)
            return null
        }

        return cached.token
    }

    fun set(domain: String, siteKey: String, token: String) {
        val key = getKey(domain, siteKey)
        cache[key] = CachedToken(token, System.currentTimeMillis())
    }
}

// Usage with caching
class CachedCapSolver(
    private val capSolver: CapSolverService,
    private val cache: TokenCache = TokenCache()
) {
    suspend fun solveReCaptchaV2Cached(websiteUrl: String, websiteKey: String): String {
        val domain = java.net.URL(websiteUrl).host

        cache.get(domain, websiteKey)?.let {
            println("Using cached token")
            return it
        }

        val token = capSolver.solveReCaptchaV2(websiteUrl, websiteKey)
        cache.set(domain, websiteKey, token)

        return token
    }
}