/*
 * Copyright (C) 2022 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.internal.systemui.lint

import com.android.SdkConstants.CLASS_CONTEXT
import com.android.tools.lint.detector.api.Category
import com.android.tools.lint.detector.api.Detector
import com.android.tools.lint.detector.api.Implementation
import com.android.tools.lint.detector.api.Issue
import com.android.tools.lint.detector.api.JavaContext
import com.android.tools.lint.detector.api.Scope
import com.android.tools.lint.detector.api.Severity
import com.android.tools.lint.detector.api.SourceCodeScanner
import com.intellij.psi.PsiMethod
import org.jetbrains.uast.UCallExpression

/** Detects usage of Context.getSystemService() and suggests to use an injected instance instead. */
@Suppress("UnstableApiUsage")
class NonInjectedServiceDetector : Detector(), SourceCodeScanner {

    override fun getApplicableMethodNames(): List<String> {
        return listOf("getSystemService", "get")
    }

    override fun visitMethodCall(context: JavaContext, node: UCallExpression, method: PsiMethod) {
        val evaluator = context.evaluator
        if (
            !evaluator.isStatic(method) &&
                method.name == "getSystemService" &&
                method.containingClass?.qualifiedName == CLASS_CONTEXT
        ) {
            context.report(
                issue = ISSUE,
                location = context.getNameLocation(node),
                message =
                    "Use `@Inject` to get system-level service handles instead of " +
                        "`Context.getSystemService()`"
            )
        } else if (
            evaluator.isStatic(method) &&
                method.name == "get" &&
                method.containingClass?.qualifiedName == "android.accounts.AccountManager"
        ) {
            context.report(
                issue = ISSUE,
                location = context.getNameLocation(node),
                message =
                    "Replace `AccountManager.get()` with an injected instance of `AccountManager`"
            )
        }
    }

    companion object {
        @JvmField
        val ISSUE: Issue =
            Issue.create(
                id = "NonInjectedService",
                briefDescription = "System service not injected",
                explanation =
                    """
                    `Context.getSystemService()` should be avoided because it makes testing \
                    difficult. Instead, use an injected service. For example, instead of calling \
                    `Context.getSystemService(UserManager.class)` in a class, annotate the class' \
                    constructor with `@Inject` and add `UserManager` to the parameters.
                    """,
                category = Category.CORRECTNESS,
                priority = 8,
                severity = Severity.WARNING,
                implementation =
                    Implementation(NonInjectedServiceDetector::class.java, Scope.JAVA_FILE_SCOPE)
            )
    }
}