lint/libs/lint-checks/src/main/java/com/android/tools/lint/checks/HardcodedValuesDetector.kt

/*
 * Copyright (C) 2011 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.tools.lint.checks

import com.android.SdkConstants.ANDROID_URI
import com.android.SdkConstants.ATTR_CONTENT_DESCRIPTION
import com.android.SdkConstants.ATTR_HINT
import com.android.SdkConstants.ATTR_LABEL
import com.android.SdkConstants.ATTR_PROMPT
import com.android.SdkConstants.ATTR_TEXT
import com.android.SdkConstants.ATTR_TITLE
import com.android.resources.ResourceFolderType
import com.android.tools.lint.checks.RestrictionsDetector.Companion.ATTR_DESCRIPTION
import com.android.tools.lint.checks.RestrictionsDetector.Companion.TAG_RESTRICTIONS
import com.android.tools.lint.detector.api.Category
import com.android.tools.lint.detector.api.Implementation
import com.android.tools.lint.detector.api.Issue
import com.android.tools.lint.detector.api.LayoutDetector
import com.android.tools.lint.detector.api.Scope
import com.android.tools.lint.detector.api.Severity
import com.android.tools.lint.detector.api.XmlContext
import org.w3c.dom.Attr
import java.util.Arrays

/**
 * Check which looks at the children of ScrollViews and ensures that they fill/match the parent
 * width instead of setting wrap_content.
 *
 *
 * TODO: Consider looking at the localization="suggested" attribute in the platform attrs.xml to
 * catch future recommended attributes.
 */
class HardcodedValuesDetector : LayoutDetector() {

    override fun getApplicableAttributes(): Collection<String>? {
        return Arrays.asList(
            // Layouts
            ATTR_TEXT,
            ATTR_CONTENT_DESCRIPTION,
            ATTR_HINT,
            ATTR_LABEL,
            ATTR_PROMPT,
            "textOn",
            "textOff",

            // Menus
            ATTR_TITLE,

            // App restrictions
            ATTR_DESCRIPTION
        )
    }

    override fun appliesTo(folderType: ResourceFolderType): Boolean {
        return (folderType == ResourceFolderType.LAYOUT ||
                folderType == ResourceFolderType.MENU ||
                folderType == ResourceFolderType.XML)
    }

    override fun visitAttribute(context: XmlContext, attribute: Attr) {
        val value = attribute.value
        if (!value.isEmpty() && value[0] != '@' && value[0] != '?') {
            // Make sure this is really one of the android: attributes
            if (ANDROID_URI != attribute.namespaceURI) {
                return
            }

            // Filter out a few special cases:

            if (value == "Hello World!") {
                // This is the default text in new templates. Users are unlikely to
                // leave this in, so let's not add warnings in the editor as their
                // welcome to Android development greeting.
                return
            }
            if (value == "Large Text" ||
                value == "Medium Text" ||
                value == "Small Text" ||
                value.startsWith("New ") && (value == "New Text" || value == "New " + attribute.ownerElement.tagName)
            ) {
                // The layout editor initially places the label "New Button", "New TextView",
                // etc on widgets dropped on the layout editor. Again, users are unlikely
                // to leave it that way, so let's not flag it until they change it.
                return
            }

            // In XML folders, currently only checking application restriction files
            // (since in general the res/xml folder can contain arbitrary XML content
            // interpreted by the app)
            if (context.resourceFolderType == ResourceFolderType.XML) {
                val tagName = attribute.ownerDocument.documentElement.tagName
                if (tagName != TAG_RESTRICTIONS) {
                    return
                }
            }

            context.report(
                ISSUE,
                attribute,
                context.getLocation(attribute),
                String.format(
                    "Hardcoded string \"%1\$s\", should use `@string` resource", value
                )
            )
        }
    }

    companion object {
        // TODO: Add additional issues here, such as hardcoded colors, hardcoded sizes, etc

        /** The main issue discovered by this detector  */
        @JvmField
        val ISSUE = Issue.create(
            id = "HardcodedText",
            briefDescription = "Hardcoded text",
            explanation = """
                Hardcoding text attributes directly in layout files is bad for several reasons:

                * When creating configuration variations (for example for landscape or \
                portrait) you have to repeat the actual text (and keep it up to date when \
                making changes)

                * The application cannot be translated to other languages by just adding new \
                translations for existing string resources.

                There are quickfixes to automatically extract this hardcoded string into a \
                resource lookup.
                """,
            category = Category.I18N,
            priority = 5,
            severity = Severity.WARNING,
            implementation = Implementation(
                HardcodedValuesDetector::class.java,
                Scope.RESOURCE_FILE_SCOPE
            )
        )
    }
}