package gitbucket.core.service

import gitbucket.core.model.{Issue, PullRequest, CommitStatus, CommitState, CommitComment}
import gitbucket.core.model.Profile._
import gitbucket.core.model.Profile.profile.blockingApi._
import difflib.{Delta, DiffUtils}
import gitbucket.core.util.SyntaxSugars._
import gitbucket.core.util.Directory._
import gitbucket.core.util.Implicits._
import gitbucket.core.util.JGitUtil
import gitbucket.core.util.JGitUtil.{CommitInfo, DiffInfo}
import gitbucket.core.view
import gitbucket.core.view.helpers
import org.eclipse.jgit.api.Git
import scala.collection.JavaConverters._

trait PullRequestService { self: IssuesService with CommitsService =>
  import PullRequestService._

  def getPullRequest(owner: String, repository: String, issueId: Int)(
    implicit s: Session
  ): Option[(Issue, PullRequest)] =
    getIssue(owner, repository, issueId.toString).flatMap { issue =>
      PullRequests.filter(_.byPrimaryKey(owner, repository, issueId)).firstOption.map { pullreq =>
        (issue, pullreq)
      }
    }

  def updateCommitId(owner: String, repository: String, issueId: Int, commitIdTo: String, commitIdFrom: String)(
    implicit s: Session
  ): Unit =
    PullRequests
      .filter(_.byPrimaryKey(owner, repository, issueId))
      .map(pr => pr.commitIdTo -> pr.commitIdFrom)
      .update((commitIdTo, commitIdFrom))

  def getPullRequestCountGroupByUser(closed: Boolean, owner: Option[String], repository: Option[String])(
    implicit s: Session
  ): List[PullRequestCount] =
    PullRequests
      .join(Issues)
      .on { (t1, t2) =>
        t1.byPrimaryKey(t2.userName, t2.repositoryName, t2.issueId)
      }
      .filter {
        case (t1, t2) =>
          (t2.closed === closed.bind) &&
            (t1.userName === owner.get.bind, owner.isDefined) &&
            (t1.repositoryName === repository.get.bind, repository.isDefined)
      }
      .groupBy { case (t1, t2) => t2.openedUserName }
      .map { case (userName, t) => userName -> t.length }
      .sortBy(_._2 desc)
      .list
      .map { x =>
        PullRequestCount(x._1, x._2)
      }

//  def getAllPullRequestCountGroupByUser(closed: Boolean, userName: String)(implicit s: Session): List[PullRequestCount] =
//    PullRequests
//      .innerJoin(Issues).on { (t1, t2) => t1.byPrimaryKey(t2.userName, t2.repositoryName, t2.issueId) }
//      .innerJoin(Repositories).on { case ((t1, t2), t3) => t2.byRepository(t3.userName, t3.repositoryName) }
//      .filter { case ((t1, t2), t3) =>
//        (t2.closed === closed.bind) &&
//          (
//            (t3.isPrivate === false.bind) ||
//            (t3.userName  === userName.bind) ||
//            (Collaborators.filter { t4 => t4.byRepository(t3.userName, t3.repositoryName) && (t4.collaboratorName === userName.bind)} exists)
//          )
//      }
//      .groupBy { case ((t1, t2), t3) => t2.openedUserName }
//      .map { case (userName, t) => userName -> t.length }
//      .sortBy(_._2 desc)
//      .list
//      .map { x => PullRequestCount(x._1, x._2) }

  def createPullRequest(
    originUserName: String,
    originRepositoryName: String,
    issueId: Int,
    originBranch: String,
    requestUserName: String,
    requestRepositoryName: String,
    requestBranch: String,
    commitIdFrom: String,
    commitIdTo: String
  )(implicit s: Session): Unit =
    PullRequests insert PullRequest(
      originUserName,
      originRepositoryName,
      issueId,
      originBranch,
      requestUserName,
      requestRepositoryName,
      requestBranch,
      commitIdFrom,
      commitIdTo
    )

  def getPullRequestsByRequest(userName: String, repositoryName: String, branch: String, closed: Option[Boolean])(
    implicit s: Session
  ): List[PullRequest] =
    PullRequests
      .join(Issues)
      .on { (t1, t2) =>
        t1.byPrimaryKey(t2.userName, t2.repositoryName, t2.issueId)
      }
      .filter {
        case (t1, t2) =>
          (t1.requestUserName === userName.bind) &&
            (t1.requestRepositoryName === repositoryName.bind) &&
            (t1.requestBranch === branch.bind) &&
            (t2.closed === closed.get.bind, closed.isDefined)
      }
      .map { case (t1, t2) => t1 }
      .list

  /**
   * for repository viewer.
   * 1. find pull request from `branch` to other branch on same repository
   *   1. return if exists pull request to `defaultBranch`
   *   2. return if exists pull request to other branch
   * 2. return None
   */
  def getPullRequestFromBranch(userName: String, repositoryName: String, branch: String, defaultBranch: String)(
    implicit s: Session
  ): Option[(PullRequest, Issue)] =
    PullRequests
      .join(Issues)
      .on { (t1, t2) =>
        t1.byPrimaryKey(t2.userName, t2.repositoryName, t2.issueId)
      }
      .filter {
        case (t1, t2) =>
          (t1.requestUserName === userName.bind) &&
            (t1.requestRepositoryName === repositoryName.bind) &&
            (t1.requestBranch === branch.bind) &&
            (t1.userName === userName.bind) &&
            (t1.repositoryName === repositoryName.bind) &&
            (t2.closed === false.bind)
      }
      .sortBy { case (t1, t2) => t1.branch =!= defaultBranch.bind }
      .firstOption

  /**
   * Fetch pull request contents into refs/pull/${issueId}/head and update pull request table.
   */
  def updatePullRequests(owner: String, repository: String, branch: String)(implicit s: Session): Unit =
    getPullRequestsByRequest(owner, repository, branch, Some(false)).foreach { pullreq =>
      if (Repositories.filter(_.byRepository(pullreq.userName, pullreq.repositoryName)).exists.run) {
        // Update the git repository
        val (commitIdTo, commitIdFrom) = JGitUtil.updatePullRequest(
          pullreq.userName,
          pullreq.repositoryName,
          pullreq.branch,
          pullreq.issueId,
          pullreq.requestUserName,
          pullreq.requestRepositoryName,
          pullreq.requestBranch
        )

        // Collect comment positions
        val positions = getCommitComments(pullreq.userName, pullreq.repositoryName, pullreq.commitIdTo, true)
          .collect {
            case CommitComment(_, _, _, commentId, _, _, Some(file), None, Some(newLine), _, _, _) =>
              (file, commentId, Right(newLine))
            case CommitComment(_, _, _, commentId, _, _, Some(file), Some(oldLine), None, _, _, _) =>
              (file, commentId, Left(oldLine))
          }
          .groupBy { case (file, _, _) => file }
          .map {
            case (file, comments) =>
              file ->
                comments.map { case (_, commentId, lineNumber) => (commentId, lineNumber) }
          }

        // Update comments position
        updatePullRequestCommentPositions(
          positions,
          pullreq.requestUserName,
          pullreq.requestRepositoryName,
          pullreq.commitIdTo,
          commitIdTo
        )

        // Update commit id in the PULL_REQUEST table
        updateCommitId(pullreq.userName, pullreq.repositoryName, pullreq.issueId, commitIdTo, commitIdFrom)
      }
    }

  def getPullRequestByRequestCommit(
    userName: String,
    repositoryName: String,
    toBranch: String,
    fromBranch: String,
    commitId: String
  )(implicit s: Session): Option[(PullRequest, Issue)] = {
    if (toBranch == fromBranch) {
      None
    } else {
      PullRequests
        .join(Issues)
        .on { (t1, t2) =>
          t1.byPrimaryKey(t2.userName, t2.repositoryName, t2.issueId)
        }
        .filter {
          case (t1, t2) =>
            (t1.userName === userName.bind) &&
              (t1.repositoryName === repositoryName.bind) &&
              (t1.branch === toBranch.bind) &&
              (t1.requestUserName === userName.bind) &&
              (t1.requestRepositoryName === repositoryName.bind) &&
              (t1.requestBranch === fromBranch.bind) &&
              (t1.commitIdTo === commitId.bind)
        }
        .firstOption
    }
  }

  private def updatePullRequestCommentPositions(
    positions: Map[String, Seq[(Int, Either[Int, Int])]],
    userName: String,
    repositoryName: String,
    oldCommitId: String,
    newCommitId: String
  )(implicit s: Session): Unit = {

    val (_, diffs) = getRequestCompareInfo(userName, repositoryName, oldCommitId, userName, repositoryName, newCommitId)

    val patchs = positions.map {
      case (file, _) =>
        diffs
          .find(x => x.oldPath == file)
          .map { diff =>
            (diff.oldContent, diff.newContent) match {
              case (Some(oldContent), Some(newContent)) => {
                val oldLines = oldContent.replace("\r\n", "\n").split("\n")
                val newLines = newContent.replace("\r\n", "\n").split("\n")
                file -> Option(DiffUtils.diff(oldLines.toList.asJava, newLines.toList.asJava))
              }
              case _ =>
                file -> None
            }
          }
          .getOrElse {
            file -> None
          }
    }

    positions.foreach {
      case (file, comments) =>
        patchs(file) match {
          case Some(patch) =>
            file -> comments.foreach {
              case (commentId, lineNumber) =>
                lineNumber match {
                  case Left(oldLine) => updateCommitCommentPosition(commentId, newCommitId, Some(oldLine), None)
                  case Right(newLine) =>
                    var counter = newLine
                    patch.getDeltas.asScala.filter(_.getOriginal.getPosition < newLine).foreach { delta =>
                      delta.getType match {
                        case Delta.TYPE.CHANGE =>
                          if (delta.getOriginal.getPosition <= newLine - 1 && newLine <= delta.getOriginal.getPosition + delta.getRevised.getLines.size) {
                            counter = -1
                          } else {
                            counter = counter + (delta.getRevised.getLines.size - delta.getOriginal.getLines.size)
                          }
                        case Delta.TYPE.INSERT => counter = counter + delta.getRevised.getLines.size
                        case Delta.TYPE.DELETE => counter = counter - delta.getOriginal.getLines.size
                      }
                    }
                    if (counter >= 0) {
                      updateCommitCommentPosition(commentId, newCommitId, None, Some(counter))
                    }
                }
            }
          case _ =>
            comments.foreach {
              case (commentId, lineNumber) =>
                lineNumber match {
                  case Right(oldLine) => updateCommitCommentPosition(commentId, newCommitId, Some(oldLine), None)
                  case Left(newLine)  => updateCommitCommentPosition(commentId, newCommitId, None, Some(newLine))
                }
            }
        }
    }
  }

  def getRequestCompareInfo(
    userName: String,
    repositoryName: String,
    branch: String,
    requestUserName: String,
    requestRepositoryName: String,
    requestCommitId: String
  ): (Seq[Seq[CommitInfo]], Seq[DiffInfo]) =
    using(
      Git.open(getRepositoryDir(userName, repositoryName)),
      Git.open(getRepositoryDir(requestUserName, requestRepositoryName))
    ) { (oldGit, newGit) =>
      val oldId = oldGit.getRepository.resolve(branch)
      val newId = newGit.getRepository.resolve(requestCommitId)

      val commits = newGit.log
        .addRange(oldId, newId)
        .call
        .iterator
        .asScala
        .map { revCommit =>
          new CommitInfo(revCommit)
        }
        .toList
        .splitWith { (commit1, commit2) =>
          helpers.date(commit1.commitTime) == view.helpers.date(commit2.commitTime)
        }

      val diffs = JGitUtil.getDiffs(newGit, Some(oldId.getName), newId.getName, true, false)

      (commits, diffs)
    }

}

object PullRequestService {

  val PullRequestLimit = 25

  case class PullRequestCount(userName: String, count: Int)

  case class MergeStatus(
    conflictMessage: Option[String],
    commitStatues: List[CommitStatus],
    branchProtection: ProtectedBranchService.ProtectedBranchInfo,
    branchIsOutOfDate: Boolean,
    hasUpdatePermission: Boolean,
    needStatusCheck: Boolean,
    hasMergePermission: Boolean,
    commitIdTo: String
  ) {

    val hasConflict = conflictMessage.isDefined
    val statuses: List[CommitStatus] =
      commitStatues ++ (branchProtection.contexts.toSet -- commitStatues.map(_.context).toSet)
        .map(CommitStatus.pending(branchProtection.owner, branchProtection.repository, _))
    val hasRequiredStatusProblem = needStatusCheck && branchProtection.contexts.exists(
      context => statuses.find(_.context == context).map(_.state) != Some(CommitState.SUCCESS)
    )
    val hasProblem = hasRequiredStatusProblem || hasConflict || (statuses.nonEmpty && CommitState.combine(
      statuses.map(_.state).toSet
    ) != CommitState.SUCCESS)
    val canUpdate = branchIsOutOfDate && !hasConflict
    val canMerge = hasMergePermission && !hasConflict && !hasRequiredStatusProblem
    lazy val commitStateSummary: (CommitState, String) = {
      val stateMap = statuses.groupBy(_.state)
      val state = CommitState.combine(stateMap.keySet)
      val summary = stateMap.map { case (keyState, states) => states.size + " " + keyState.name }.mkString(", ")
      state -> summary
    }
    lazy val statusesAndRequired: List[(CommitStatus, Boolean)] = statuses.map { s =>
      s -> branchProtection.contexts.contains(s.context)
    }
    lazy val isAllSuccess = commitStateSummary._1 == CommitState.SUCCESS
  }
}