TrailingCommaOnCallSiteRule.kt

package com.pinterest.ktlint.ruleset.standard

import com.pinterest.ktlint.core.Rule
import com.pinterest.ktlint.core.api.EditorConfigProperties
import com.pinterest.ktlint.core.api.UsesEditorConfigProperties
import com.pinterest.ktlint.core.ast.ElementType
import com.pinterest.ktlint.core.ast.children
import com.pinterest.ktlint.ruleset.standard.internal.trailingcomma.reportAndCorrectTrailingCommaNodeBefore
import kotlin.properties.Delegates
import org.ec4j.core.model.PropertyType
import org.ec4j.core.model.PropertyType.PropertyValueParser
import org.jetbrains.kotlin.com.intellij.lang.ASTNode
import org.jetbrains.kotlin.com.intellij.psi.tree.TokenSet

/**
 * Linting trailing comma for call site.
 *
 * @see [Kotlin Style Guide](https://kotlinlang.org/docs/coding-conventions.html#trailing-commas)
 */
public class TrailingCommaOnCallSiteRule :
    Rule(
        id = "trailing-comma-on-call-site",
        visitorModifiers = setOf(
            VisitorModifier.RunAfterRule(
                ruleId = "standard:indent",
                loadOnlyWhenOtherRuleIsLoaded = true,
                runOnlyWhenOtherRuleIsEnabled = true
            ),
            VisitorModifier.RunAsLateAsPossible
        )
    ),
    UsesEditorConfigProperties {

    override val editorConfigProperties: List<UsesEditorConfigProperties.EditorConfigProperty<*>> = listOf(
        allowTrailingCommaOnCallSiteProperty
    )

    private var allowTrailingCommaOnCallSite by Delegates.notNull<Boolean>()

    private fun ASTNode.isTrailingCommaAllowed() =
        elementType in TYPES_ON_CALL_SITE && allowTrailingCommaOnCallSite

    override fun beforeFirstNode(editorConfigProperties: EditorConfigProperties) {
        allowTrailingCommaOnCallSite = editorConfigProperties.getEditorConfigValue(allowTrailingCommaOnCallSiteProperty)
    }

    override fun beforeVisitChildNodes(
        node: ASTNode,
        autoCorrect: Boolean,
        emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> Unit
    ) {
        // Keep processing of element types in sync with Intellij Kotlin formatting settings.
        // https://github.com/JetBrains/intellij-kotlin/blob/master/formatter/src/org/jetbrains/kotlin/idea/formatter/trailingComma/util.kt
        when (node.elementType) {
            ElementType.COLLECTION_LITERAL_EXPRESSION -> visitCollectionLiteralExpression(node, autoCorrect, emit)
            ElementType.INDICES -> visitIndices(node, autoCorrect, emit)
            ElementType.TYPE_ARGUMENT_LIST -> visitTypeList(node, autoCorrect, emit)
            ElementType.VALUE_ARGUMENT_LIST -> visitValueList(node, autoCorrect, emit)
            else -> Unit
        }
    }

    private fun visitCollectionLiteralExpression(
        node: ASTNode,
        autoCorrect: Boolean,
        emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> Unit
    ) {
        val inspectNode = node
            .children()
            .last { it.elementType == ElementType.RBRACKET }
        node.reportAndCorrectTrailingCommaNodeBefore(
            inspectNode = inspectNode,
            emit = emit,
            isTrailingCommaAllowed = node.isTrailingCommaAllowed(),
            autoCorrect = autoCorrect
        )
    }

    private fun visitIndices(
        node: ASTNode,
        autoCorrect: Boolean,
        emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> Unit
    ) {
        val inspectNode = node
            .children()
            .last { it.elementType == ElementType.RBRACKET }
        node.reportAndCorrectTrailingCommaNodeBefore(
            inspectNode = inspectNode,
            emit = emit,
            isTrailingCommaAllowed = node.isTrailingCommaAllowed(),
            autoCorrect = autoCorrect
        )
    }

    private fun visitValueList(
        node: ASTNode,
        autoCorrect: Boolean,
        emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> Unit
    ) {
        if (node.treeParent.elementType != ElementType.FUNCTION_LITERAL) {
            node
                .children()
                .lastOrNull { it.elementType == ElementType.RPAR }
                ?.let { inspectNode ->
                    node.reportAndCorrectTrailingCommaNodeBefore(
                        inspectNode = inspectNode,
                        emit = emit,
                        isTrailingCommaAllowed = node.isTrailingCommaAllowed(),
                        autoCorrect = autoCorrect
                    )
                }
        }
    }

    private fun visitTypeList(
        node: ASTNode,
        autoCorrect: Boolean,
        emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> Unit
    ) {
        val inspectNode = node
            .children()
            .first { it.elementType == ElementType.GT }
        node.reportAndCorrectTrailingCommaNodeBefore(
            inspectNode = inspectNode,
            emit = emit,
            isTrailingCommaAllowed = node.isTrailingCommaAllowed(),
            autoCorrect = autoCorrect
        )
    }

    public companion object {

        internal const val ALLOW_TRAILING_COMMA_ON_CALL_SITE_NAME = "ij_kotlin_allow_trailing_comma_on_call_site"
        private const val ALLOW_TRAILING_COMMA_ON_CALL_SITE_DESCRIPTION =
            "Defines whether a trailing comma (or no trailing comma)" +
                "should be enforced on the calling side," +
                "e.g. argument-list, when-entries, lambda-arguments, indices, etc."
        private val BOOLEAN_VALUES_SET = setOf("true", "false")

        // TODO: Rename property to trailingCommaOnCallSite. The word 'allow' is misleading as the comma is
        //       enforced when the property is enabled and prohibited when disabled.
        public val allowTrailingCommaOnCallSiteProperty: UsesEditorConfigProperties.EditorConfigProperty<Boolean> =
            UsesEditorConfigProperties.EditorConfigProperty(
                type = PropertyType.LowerCasingPropertyType(
                    ALLOW_TRAILING_COMMA_ON_CALL_SITE_NAME,
                    ALLOW_TRAILING_COMMA_ON_CALL_SITE_DESCRIPTION,
                    PropertyValueParser.BOOLEAN_VALUE_PARSER,
                    BOOLEAN_VALUES_SET
                ),
                defaultValue = false
            )

        private val TYPES_ON_CALL_SITE = TokenSet.create(
            ElementType.COLLECTION_LITERAL_EXPRESSION,
            ElementType.INDICES,
            ElementType.TYPE_ARGUMENT_LIST,
            ElementType.VALUE_ARGUMENT_LIST
        )
    }
}