package static_analysis.linters

import io.gitlab.arturbosch.detekt.Detekt
import org.gradle.api.Project
import org.gradle.api.file.FileTree
import static_analysis.errors.DetektError
import static_analysis.errors.StaticAnalysisError
import static_analysis.plugins.StaticAnalysisExtension
import static_analysis.utils.getSources
import static_analysis.utils.runCommand
import static_analysis.utils.typedChildren
import static_analysis.utils.xmlParser
import java.io.File

class DetektLinter : Linter {

    private companion object {
        const val ONLY_DIFFS_FLAG = "only-diffs"
        const val GET_GIT_DIFFS_COMMAND = "git diff --name-only --ignore-submodules"
    }

    override val name: String = "Detekt"

    override fun getErrors(project: Project): List<StaticAnalysisError> = xmlParser(project.getDetektReportFile())
            .typedChildren()
            .filter { fileNode -> fileNode.name() == "file" }
            .map { fileNode ->
                fileNode
                        .typedChildren()
                        .filter { it.name() == "error" }
                        .map { errorNode ->
                            DetektError(
                                    filePath = fileNode.attribute("name") as String,
                                    fileLine = errorNode.attribute("line") as String,
                                    errorId = errorNode.attribute("source") as String,
                                    description = errorNode.attribute("message") as String
                            )
                        }
            }
            .flatten()

    override fun setupForProject(project: Project, extension: StaticAnalysisExtension) {
        project.afterEvaluate {
            tasks.withType(Detekt::class.java) {
                exclude("**/test/**")
                exclude("resources/")
                exclude("build/")
                exclude("tmp/")
                jvmTarget = "1.8"

                config.setFrom(files("${extension.buildScriptDir!!}/static_analysis_configs/detekt-config.yml"))
                reports {
                    txt.enabled = false
                    html.enabled = false
                    xml {
                        enabled = true
                        destination = getDetektReportFile()
                    }
                }

                val isOnlyDiffs = properties["args"] == ONLY_DIFFS_FLAG // example: ./gradlew detektAnalysis -Pargs="only-diffs"

                source = getSources(extension.excludes, isOnlyDiffs, project)
            }
        }
    }

    private fun getSources(excludes: String, isOnlyDiffs: Boolean, project: Project): FileTree = when {
        isOnlyDiffs -> getGitDiffFiles(excludes, project)
        else -> project.getSources(excludes)
    }

    private fun getGitDiffFiles(excludes: String, project: Project): FileTree {
        val gitDiffs = GET_GIT_DIFFS_COMMAND.runCommand() ?: return project.files().asFileTree

        val diffFiles = gitDiffs.lines()
                .map { File(it) }
                .filter { (it.extension == "kt" || it.extension == "java") && !excludes.contains(it.path) }
                .toList()

        return project.files(diffFiles).asFileTree
    }

    override fun getTaskNames(project: Project, buildType: String?): List<String> = listOf(":detekt")

    private fun Project.getDetektReportFile() = file("${rootProject.buildDir}/reports/detekt.xml")

}