tachiyomi/app/src/main/java/eu/kanade/presentation/webview/WebViewScreenContent.kt

package eu.kanade.presentation.webview

import android.content.pm.ApplicationInfo
import android.graphics.Bitmap
import android.webkit.WebResourceRequest
import android.webkit.WebView
import androidx.compose.foundation.clickable
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.material.icons.Icons
import androidx.compose.material.icons.outlined.ArrowBack
import androidx.compose.material.icons.outlined.ArrowForward
import androidx.compose.material.icons.outlined.Close
import androidx.compose.material3.LinearProgressIndicator
import androidx.compose.material3.MaterialTheme
import androidx.compose.material3.Surface
import androidx.compose.runtime.Composable
import androidx.compose.runtime.getValue
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.runtime.rememberCoroutineScope
import androidx.compose.runtime.setValue
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.draw.clip
import androidx.compose.ui.platform.LocalUriHandler
import androidx.compose.ui.res.stringResource
import androidx.compose.ui.unit.dp
import com.google.accompanist.web.AccompanistWebViewClient
import com.google.accompanist.web.LoadingState
import com.google.accompanist.web.WebView
import com.google.accompanist.web.rememberWebViewNavigator
import com.google.accompanist.web.rememberWebViewState
import eu.kanade.presentation.components.AppBar
import eu.kanade.presentation.components.AppBarActions
import eu.kanade.presentation.components.WarningBanner
import eu.kanade.tachiyomi.BuildConfig
import eu.kanade.tachiyomi.R
import eu.kanade.tachiyomi.util.system.getHtml
import eu.kanade.tachiyomi.util.system.setDefaultSettings
import kotlinx.coroutines.launch
import tachiyomi.presentation.core.components.material.Scaffold

@Composable
fun WebViewScreenContent(
    onNavigateUp: () -> Unit,
    initialTitle: String?,
    url: String,
    headers: Map<String, String> = emptyMap(),
    onUrlChange: (String) -> Unit = {},
    onShare: (String) -> Unit,
    onOpenInBrowser: (String) -> Unit,
    onClearCookies: (String) -> Unit,
) {
    val state = rememberWebViewState(url = url, additionalHttpHeaders = headers)
    val navigator = rememberWebViewNavigator()
    val uriHandler = LocalUriHandler.current
    val scope = rememberCoroutineScope()

    var currentUrl by remember { mutableStateOf(url) }
    var showCloudflareHelp by remember { mutableStateOf(false) }

    val webClient = remember {
        object : AccompanistWebViewClient() {
            override fun onPageStarted(view: WebView, url: String?, favicon: Bitmap?) {
                super.onPageStarted(view, url, favicon)
                url?.let {
                    currentUrl = it
                    onUrlChange(it)
                }
            }

            override fun onPageFinished(view: WebView, url: String?) {
                super.onPageFinished(view, url)
                scope.launch {
                    val html = view.getHtml()
                    showCloudflareHelp = "window._cf_chl_opt" in html || "Ray ID is" in html
                }
            }

            override fun doUpdateVisitedHistory(
                view: WebView,
                url: String?,
                isReload: Boolean,
            ) {
                super.doUpdateVisitedHistory(view, url, isReload)
                url?.let {
                    currentUrl = it
                    onUrlChange(it)
                }
            }

            override fun shouldOverrideUrlLoading(
                view: WebView?,
                request: WebResourceRequest?,
            ): Boolean {
                request?.let {
                    // Don't attempt to open blobs as webpages
                    if (it.url.toString().startsWith("blob:http")) {
                        return false
                    }

                    // Continue with request, but with custom headers
                    view?.loadUrl(it.url.toString(), headers)
                }
                return super.shouldOverrideUrlLoading(view, request)
            }
        }
    }

    Scaffold(
        topBar = {
            Box {
                Column {
                    AppBar(
                        title = state.pageTitle ?: initialTitle,
                        subtitle = currentUrl,
                        navigateUp = onNavigateUp,
                        navigationIcon = Icons.Outlined.Close,
                        actions = {
                            AppBarActions(
                                listOf(
                                    AppBar.Action(
                                        title = stringResource(R.string.action_webview_back),
                                        icon = Icons.Outlined.ArrowBack,
                                        onClick = {
                                            if (navigator.canGoBack) {
                                                navigator.navigateBack()
                                            }
                                        },
                                        enabled = navigator.canGoBack,
                                    ),
                                    AppBar.Action(
                                        title = stringResource(R.string.action_webview_forward),
                                        icon = Icons.Outlined.ArrowForward,
                                        onClick = {
                                            if (navigator.canGoForward) {
                                                navigator.navigateForward()
                                            }
                                        },
                                        enabled = navigator.canGoForward,
                                    ),
                                    AppBar.OverflowAction(
                                        title = stringResource(R.string.action_webview_refresh),
                                        onClick = { navigator.reload() },
                                    ),
                                    AppBar.OverflowAction(
                                        title = stringResource(R.string.action_share),
                                        onClick = { onShare(currentUrl) },
                                    ),
                                    AppBar.OverflowAction(
                                        title = stringResource(R.string.action_open_in_browser),
                                        onClick = { onOpenInBrowser(currentUrl) },
                                    ),
                                    AppBar.OverflowAction(
                                        title = stringResource(R.string.pref_clear_cookies),
                                        onClick = { onClearCookies(currentUrl) },
                                    ),
                                ),
                            )
                        },
                    )

                    if (showCloudflareHelp) {
                        Surface(
                            modifier = Modifier.padding(8.dp),
                        ) {
                            WarningBanner(
                                textRes = R.string.information_cloudflare_help,
                                modifier = Modifier
                                    .clip(MaterialTheme.shapes.small)
                                    .clickable {
                                        uriHandler.openUri(
                                            "https://tachiyomi.org/docs/guides/troubleshooting/#cloudflare",
                                        )
                                    },
                            )
                        }
                    }
                }
                when (val loadingState = state.loadingState) {
                    is LoadingState.Initializing -> LinearProgressIndicator(
                        modifier = Modifier
                            .fillMaxWidth()
                            .align(Alignment.BottomCenter),
                    )
                    is LoadingState.Loading -> LinearProgressIndicator(
                        progress = (loadingState as? LoadingState.Loading)?.progress ?: 1f,
                        modifier = Modifier
                            .fillMaxWidth()
                            .align(Alignment.BottomCenter),
                    )
                    else -> {}
                }
            }
        },
    ) { contentPadding ->
        WebView(
            state = state,
            modifier = Modifier
                .fillMaxSize()
                .padding(contentPadding),
            navigator = navigator,
            onCreated = { webView ->
                webView.setDefaultSettings()

                // Debug mode (chrome://inspect/#devices)
                if (BuildConfig.DEBUG &&
                    0 != webView.context.applicationInfo.flags and ApplicationInfo.FLAG_DEBUGGABLE
                ) {
                    WebView.setWebContentsDebuggingEnabled(true)
                }

                headers["user-agent"]?.let {
                    webView.settings.userAgentString = it
                }
            },
            client = webClient,
        )
    }
}