app/ansible/RoleParser.scala

package ansible

import java.nio.file.{Files, Path}

import com.fasterxml.jackson.databind.ObjectMapper
import com.fasterxml.jackson.dataformat.yaml.YAMLFactory
import models.{Markdown, RoleId, RoleSummary, Yaml}

import scala.jdk.CollectionConverters._
import scala.util.Try

object RoleParser {

  private val yamlFactory = new YAMLFactory()

  def createRoleSummary(roleDir: Path): Option[RoleSummary] = {
    val roleId = RoleId(roleDir.getFileName.toString)
    val dependsOn = parseDependencies(roleDir.resolve("meta/main.yml"))
    val tasksMain = readYamlFile(roleDir.resolve("tasks/main.yml"))
    val readme = readReadme(roleDir.resolve("README.md"))

    for {
      yaml <- tasksMain
    } yield {
      RoleSummary(roleId, dependsOn, yaml, readme)
    }
  }

  def readReadme(path: Path): Option[Markdown] = {
    if (Files.isRegularFile(path)) {
      Try(Files.readAllLines(path)).toOption
        .map(lines => Markdown(lines.asScala.mkString("\n")))
    } else None
  }

  def parseDependencies(metaMainYaml: Path): Set[RoleId] = {
    readYamlFile(metaMainYaml)
      .map(parseDependenciesFromYaml)
      .getOrElse(Set.empty)
  }

  /** Extracts the role IDs from YAML that looks like this:
    *
    * {{{
    * ---
    * dependencies:
    *   - foo
    *   - { role: bar, baz: wow }
    * }}}
    */
  def parseDependenciesFromYaml(yaml: Yaml): Set[RoleId] = {
    val mapper = new ObjectMapper(yamlFactory)
    val jmap =
      mapper.readValue(yaml.content, classOf[java.util.Map[String, Any]])
    val deps = jmap.asScala
      .get("dependencies")
      .map(_.asInstanceOf[java.util.List[Any]].asScala)
      .getOrElse(Nil)
    deps
      .collect {
        case roleId: String => Some(RoleId(roleId))
        case customisedRole: java.util.Map[String, String] @unchecked =>
          customisedRole.asScala.get("role").map(RoleId(_))
      }
      .flatten
      .toSet
  }

  private def readYamlFile(path: Path): Option[Yaml] = {
    if (Files.isRegularFile(path)) {
      Try(Files.readAllLines(path)).toOption
        .map(lines => Yaml(lines.asScala.mkString("\n")))
    } else None
  }

}