package app

import util._
import util.Directory._
import util.Implicits._
import util.ControlUtil._
import service._
import org.eclipse.jgit.api.Git
import jp.sf.amateras.scalatra.forms._
import org.eclipse.jgit.transport.RefSpec
import scala.collection.JavaConverters._
import org.eclipse.jgit.lib.{ObjectId, CommitBuilder, PersonIdent}
import service.IssuesService._
import service.PullRequestService._
import org.slf4j.LoggerFactory
import org.eclipse.jgit.merge.MergeStrategy
import org.eclipse.jgit.errors.NoMergeBaseException
import service.WebHookService._
import util.JGitUtil.DiffInfo
import util.JGitUtil.CommitInfo
import model.{PullRequest, Issue}


class PullRequestsController extends PullRequestsControllerBase
  with RepositoryService with AccountService with IssuesService with PullRequestService with MilestonesService with LabelsService
  with CommitsService with ActivityService with WebHookPullRequestService with ReferrerAuthenticator with CollaboratorsAuthenticator

trait PullRequestsControllerBase extends ControllerBase {
  self: RepositoryService with AccountService with IssuesService with MilestonesService with LabelsService
    with CommitsService with ActivityService with PullRequestService with WebHookPullRequestService with ReferrerAuthenticator with CollaboratorsAuthenticator =>

  private val logger = LoggerFactory.getLogger(classOf[PullRequestsControllerBase])

  val pullRequestForm = mapping(
    "title"                 -> trim(label("Title"  , text(required, maxlength(100)))),
    "content"               -> trim(label("Content", optional(text()))),
    "targetUserName"        -> trim(text(required, maxlength(100))),
    "targetBranch"          -> trim(text(required, maxlength(100))),
    "requestUserName"       -> trim(text(required, maxlength(100))),
    "requestRepositoryName" -> trim(text(required, maxlength(100))),
    "requestBranch"         -> trim(text(required, maxlength(100))),
    "commitIdFrom"          -> trim(text(required, maxlength(40))),
    "commitIdTo"            -> trim(text(required, maxlength(40)))
  )(PullRequestForm.apply)

  val mergeForm = mapping(
    "message" -> trim(label("Message", text(required)))
  )(MergeForm.apply)

  case class PullRequestForm(
    title: String,
    content: Option[String],
    targetUserName: String,
    targetBranch: String,
    requestUserName: String,
    requestRepositoryName: String,
    requestBranch: String,
    commitIdFrom: String,
    commitIdTo: String)

  case class MergeForm(message: String)

  get("/:owner/:repository/pulls")(referrersOnly { repository =>
    val q = request.getParameter("q")
    if(Option(q).exists(_.contains("is:issue"))){
      redirect(s"/${repository.owner}/${repository.name}/issues?q=" + StringUtil.urlEncode(q))
    } else {
      searchPullRequests(None, repository)
    }
  })

  /**
   * https://developer.github.com/v3/pulls/#list-pull-requests
   */
  get("/api/v3/repos/:owner/:repository/pulls")(referrersOnly { repository =>
    val page       = IssueSearchCondition.page(request)
    // TODO: more api spec condition
    val condition = IssueSearchCondition(request)
    val baseOwner = getAccountByUserName(repository.owner).get
    val issues:List[(model.Issue, model.Account, Int, model.PullRequest, model.Repository, model.Account)] = searchPullRequestByApi(condition, (page - 1) * PullRequestLimit, PullRequestLimit, repository.owner -> repository.name)
    apiJson(issues.map{case (issue, issueUser, commentCount, pullRequest, headRepo, headOwner) =>
      WebHookPullRequest(
        issue,
        pullRequest,
        WebHookRepository(headRepo, WebHookApiUser(headOwner)),
        WebHookRepository(repository, WebHookApiUser(baseOwner)),
        WebHookApiUser(issueUser)) })
  })

  get("/:owner/:repository/pull/:id")(referrersOnly { repository =>
    params("id").toIntOpt.flatMap{ issueId =>
      val owner = repository.owner
      val name = repository.name
      getPullRequest(owner, name, issueId) map { case(issue, pullreq) =>
        using(Git.open(getRepositoryDir(owner, name))){ git =>
          val (commits, diffs) =
            getRequestCompareInfo(owner, name, pullreq.commitIdFrom, owner, name, pullreq.commitIdTo)

          pulls.html.pullreq(
            issue, pullreq,
            (commits.flatten.map(commit => getCommitComments(owner, name, commit.id, true)).flatten.toList ::: getComments(owner, name, issueId))
              .sortWith((a, b) => a.registeredDate before b.registeredDate),
            getIssueLabels(owner, name, issueId),
            (getCollaborators(owner, name) ::: (if(getAccountByUserName(owner).get.isGroupAccount) Nil else List(owner))).sorted,
            getMilestonesWithIssueCount(owner, name),
            getLabels(owner, name),
            commits,
            diffs,
            hasWritePermission(owner, name, context.loginAccount),
            repository)
        }
      }
    } getOrElse NotFound
  })

  /**
   * https://developer.github.com/v3/pulls/#get-a-single-pull-request
   */
  get("/api/v3/repos/:owner/:repository/pulls/:id")(referrersOnly { repository =>
    (for{
      issueId <- params("id").toIntOpt
      (issue, pullRequest) <- getPullRequest(repository.owner, repository.name, issueId)
      users = getAccountsByUserNames(Set(repository.owner, pullRequest.requestUserName, issue.userName), Set())
      baseOwner <- users.get(repository.owner)
      headOwner <- users.get(pullRequest.requestUserName)
      issueUser <- users.get(issue.userName)
      headRepo  <- getRepository(pullRequest.requestUserName, pullRequest.requestRepositoryName, baseUrl)
    } yield {
      apiJson(WebHookPullRequest(
        issue,
        pullRequest,
        WebHookRepository(headRepo, WebHookApiUser(headOwner)),
        WebHookRepository(repository, WebHookApiUser(baseOwner)),
        WebHookApiUser(issueUser)))
    }).getOrElse(NotFound)
  })

  /**
   * https://developer.github.com/v3/pulls/#list-commits-on-a-pull-request
   */
  get("/api/v3/repos/:owner/:repository/pulls/:id/commits")(referrersOnly { repository =>
    val owner = repository.owner
    val name = repository.name
    params("id").toIntOpt.flatMap{ issueId =>
      getPullRequest(owner, name, issueId) map { case(issue, pullreq) =>
        using(Git.open(getRepositoryDir(owner, name))){ git =>
          val oldId = git.getRepository.resolve(pullreq.commitIdFrom)
          val newId = git.getRepository.resolve(pullreq.commitIdTo)
          val repoFullName = s"${owner}/${name}"
          val commits = git.log.addRange(oldId, newId).call.iterator.asScala.map(c => WebHookCommitListItem(new CommitInfo(c), repoFullName)).toList
          apiJson(commits)
        }
      }
    } getOrElse NotFound
  })

  ajaxGet("/:owner/:repository/pull/:id/mergeguide")(collaboratorsOnly { repository =>
    params("id").toIntOpt.flatMap{ issueId =>
      val owner = repository.owner
      val name  = repository.name
      getPullRequest(owner, name, issueId) map { case(issue, pullreq) =>
        pulls.html.mergeguide(
          checkConflictInPullRequest(owner, name, pullreq.branch, pullreq.requestUserName, name, pullreq.requestBranch, issueId),
          pullreq,
          s"${context.baseUrl}/git/${pullreq.requestUserName}/${pullreq.requestRepositoryName}.git")
      }
    } getOrElse NotFound
  })

  get("/:owner/:repository/pull/:id/delete/*")(collaboratorsOnly { repository =>
    params("id").toIntOpt.map { issueId =>
      val branchName = multiParams("splat").head
      val userName   = context.loginAccount.get.userName
      if(repository.repository.defaultBranch != branchName){
        using(Git.open(getRepositoryDir(repository.owner, repository.name))){ git =>
          git.branchDelete().setForce(true).setBranchNames(branchName).call()
          recordDeleteBranchActivity(repository.owner, repository.name, userName, branchName)
        }
      }
      createComment(repository.owner, repository.name, userName, issueId, branchName, "delete_branch")
      redirect(s"/${repository.owner}/${repository.name}/pull/${issueId}")
    } getOrElse NotFound
  })

  post("/:owner/:repository/pull/:id/merge", mergeForm)(collaboratorsOnly { (form, repository) =>
    params("id").toIntOpt.flatMap { issueId =>
      val owner = repository.owner
      val name  = repository.name
      LockUtil.lock(s"${owner}/${name}"){
        getPullRequest(owner, name, issueId).map { case (issue, pullreq) =>
          using(Git.open(getRepositoryDir(owner, name))) { git =>
            // mark issue as merged and close.
            val loginAccount = context.loginAccount.get
            createComment(owner, name, loginAccount.userName, issueId, form.message, "merge")
            createComment(owner, name, loginAccount.userName, issueId, "Close", "close")
            updateClosed(owner, name, issueId, true)

            // record activity
            recordMergeActivity(owner, name, loginAccount.userName, issueId, form.message)

            // merge
            val mergeBaseRefName = s"refs/heads/${pullreq.branch}"
            val merger = MergeStrategy.RECURSIVE.newMerger(git.getRepository, true)
            val mergeBaseTip = git.getRepository.resolve(mergeBaseRefName)
            val mergeTip = git.getRepository.resolve(s"refs/pull/${issueId}/head")
            val conflicted = try {
              !merger.merge(mergeBaseTip, mergeTip)
            } catch {
              case e: NoMergeBaseException => true
            }
            if (conflicted) {
              throw new RuntimeException("This pull request can't merge automatically.")
            }

            // creates merge commit
            val mergeCommit = new CommitBuilder()
            mergeCommit.setTreeId(merger.getResultTreeId)
            mergeCommit.setParentIds(Array[ObjectId](mergeBaseTip, mergeTip): _*)
            val personIdent = new PersonIdent(loginAccount.fullName, loginAccount.mailAddress)
            mergeCommit.setAuthor(personIdent)
            mergeCommit.setCommitter(personIdent)
            mergeCommit.setMessage(s"Merge pull request #${issueId} from ${pullreq.requestUserName}/${pullreq.requestBranch}\n\n" +
                                   form.message)

            // insertObject and got mergeCommit Object Id
            val inserter = git.getRepository.newObjectInserter
            val mergeCommitId = inserter.insert(mergeCommit)
            inserter.flush()
            inserter.release()

            // update refs
            val refUpdate = git.getRepository.updateRef(mergeBaseRefName)
            refUpdate.setNewObjectId(mergeCommitId)
            refUpdate.setForceUpdate(false)
            refUpdate.setRefLogIdent(personIdent)
            refUpdate.setRefLogMessage("merged", true)
            refUpdate.update()

            val (commits, _) = getRequestCompareInfo(owner, name, pullreq.commitIdFrom,
              pullreq.requestUserName, pullreq.requestRepositoryName, pullreq.commitIdTo)

            // close issue by content of pull request
            val defaultBranch = getRepository(owner, name, context.baseUrl).get.repository.defaultBranch
            if(pullreq.branch == defaultBranch){
              commits.flatten.foreach { commit =>
                closeIssuesFromMessage(commit.fullMessage, loginAccount.userName, owner, name)
              }
              issue.content match {
                case Some(content) => closeIssuesFromMessage(content, loginAccount.userName, owner, name)
                case _ =>
              }
              closeIssuesFromMessage(form.message, loginAccount.userName, owner, name)
            }
            // call web hook
            callPullRequestWebHook("closed", repository, issueId, context.baseUrl, context.loginAccount.get)

            // notifications
            Notifier().toNotify(repository, issueId, "merge"){
              Notifier.msgStatus(s"${context.baseUrl}/${owner}/${name}/pull/${issueId}")
            }

            redirect(s"/${owner}/${name}/pull/${issueId}")
          }
        }
      }
    } getOrElse NotFound
  })

  get("/:owner/:repository/compare")(referrersOnly { forkedRepository =>
    (forkedRepository.repository.originUserName, forkedRepository.repository.originRepositoryName) match {
      case (Some(originUserName), Some(originRepositoryName)) => {
        getRepository(originUserName, originRepositoryName, context.baseUrl).map { originRepository =>
          using(
            Git.open(getRepositoryDir(originUserName, originRepositoryName)),
            Git.open(getRepositoryDir(forkedRepository.owner, forkedRepository.name))
          ){ (oldGit, newGit) =>
            val oldBranch = JGitUtil.getDefaultBranch(oldGit, originRepository).get._2
            val newBranch = JGitUtil.getDefaultBranch(newGit, forkedRepository).get._2

            redirect(s"/${forkedRepository.owner}/${forkedRepository.name}/compare/${originUserName}:${oldBranch}...${newBranch}")
          }
        } getOrElse NotFound
      }
      case _ => {
        using(Git.open(getRepositoryDir(forkedRepository.owner, forkedRepository.name))){ git =>
          JGitUtil.getDefaultBranch(git, forkedRepository).map { case (_, defaultBranch) =>
            redirect(s"/${forkedRepository.owner}/${forkedRepository.name}/compare/${defaultBranch}...${defaultBranch}")
          } getOrElse {
            redirect(s"/${forkedRepository.owner}/${forkedRepository.name}")
          }
        }
      }
    }
  })

  get("/:owner/:repository/compare/*...*")(referrersOnly { forkedRepository =>
    val Seq(origin, forked) = multiParams("splat")
    val (originOwner, tmpOriginBranch) = parseCompareIdentifie(origin, forkedRepository.owner)
    val (forkedOwner, tmpForkedBranch) = parseCompareIdentifie(forked, forkedRepository.owner)

    (for(
      originRepositoryName <- if(originOwner == forkedOwner){
        Some(forkedRepository.name)
      } else {
        forkedRepository.repository.originRepositoryName.orElse {
          getForkedRepositories(forkedRepository.owner, forkedRepository.name).find(_._1 == originOwner).map(_._2)
        }
      };
      originRepository <- getRepository(originOwner, originRepositoryName, context.baseUrl)
    ) yield {
      using(
        Git.open(getRepositoryDir(originRepository.owner, originRepository.name)),
        Git.open(getRepositoryDir(forkedRepository.owner, forkedRepository.name))
      ){ case (oldGit, newGit) =>
        val originBranch = JGitUtil.getDefaultBranch(oldGit, originRepository, tmpOriginBranch).get._2
        val forkedBranch = JGitUtil.getDefaultBranch(newGit, forkedRepository, tmpForkedBranch).get._2

        val forkedId = JGitUtil.getForkedCommitId(oldGit, newGit,
          originRepository.owner, originRepository.name, originBranch,
          forkedRepository.owner, forkedRepository.name, forkedBranch)

        val oldId = oldGit.getRepository.resolve(forkedId)
        val newId = newGit.getRepository.resolve(forkedBranch)

        val (commits, diffs) = getRequestCompareInfo(
          originRepository.owner, originRepository.name, oldId.getName,
          forkedRepository.owner, forkedRepository.name, newId.getName)

        pulls.html.compare(
          commits,
          diffs,
          (forkedRepository.repository.originUserName, forkedRepository.repository.originRepositoryName) match {
            case (Some(userName), Some(repositoryName)) => (userName, repositoryName) :: getForkedRepositories(userName, repositoryName)
            case _ => (forkedRepository.owner, forkedRepository.name) :: getForkedRepositories(forkedRepository.owner, forkedRepository.name)
          },
          commits.flatten.map(commit => getCommitComments(forkedRepository.owner, forkedRepository.name, commit.id, false)).flatten.toList,
          originBranch,
          forkedBranch,
          oldId.getName,
          newId.getName,
          forkedRepository,
          originRepository,
          forkedRepository,
          hasWritePermission(forkedRepository.owner, forkedRepository.name, context.loginAccount))
      }
    }) getOrElse NotFound
  })

  ajaxGet("/:owner/:repository/compare/*...*/mergecheck")(collaboratorsOnly { forkedRepository =>
    val Seq(origin, forked) = multiParams("splat")
    val (originOwner, tmpOriginBranch) = parseCompareIdentifie(origin, forkedRepository.owner)
    val (forkedOwner, tmpForkedBranch) = parseCompareIdentifie(forked, forkedRepository.owner)

    (for(
      originRepositoryName <- if(originOwner == forkedOwner){
        Some(forkedRepository.name)
      } else {
        forkedRepository.repository.originRepositoryName.orElse {
          getForkedRepositories(forkedRepository.owner, forkedRepository.name).find(_._1 == originOwner).map(_._2)
        }
      };
      originRepository <- getRepository(originOwner, originRepositoryName, context.baseUrl)
    ) yield {
      using(
        Git.open(getRepositoryDir(originRepository.owner, originRepository.name)),
        Git.open(getRepositoryDir(forkedRepository.owner, forkedRepository.name))
      ){ case (oldGit, newGit) =>
        val originBranch = JGitUtil.getDefaultBranch(oldGit, originRepository, tmpOriginBranch).get._2
        val forkedBranch = JGitUtil.getDefaultBranch(newGit, forkedRepository, tmpForkedBranch).get._2

        pulls.html.mergecheck(
          checkConflict(originRepository.owner, originRepository.name, originBranch,
                        forkedRepository.owner, forkedRepository.name, forkedBranch))
      }
    }) getOrElse NotFound
  })

  post("/:owner/:repository/pulls/new", pullRequestForm)(referrersOnly { (form, repository) =>
    val loginUserName = context.loginAccount.get.userName

    val issueId = createIssue(
      owner            = repository.owner,
      repository       = repository.name,
      loginUser        = loginUserName,
      title            = form.title,
      content          = form.content,
      assignedUserName = None,
      milestoneId      = None,
      isPullRequest    = true)

    createPullRequest(
      originUserName        = repository.owner,
      originRepositoryName  = repository.name,
      issueId               = issueId,
      originBranch          = form.targetBranch,
      requestUserName       = form.requestUserName,
      requestRepositoryName = form.requestRepositoryName,
      requestBranch         = form.requestBranch,
      commitIdFrom          = form.commitIdFrom,
      commitIdTo            = form.commitIdTo)

    // fetch requested branch
    using(Git.open(getRepositoryDir(repository.owner, repository.name))){ git =>
      git.fetch
        .setRemote(getRepositoryDir(form.requestUserName, form.requestRepositoryName).toURI.toString)
        .setRefSpecs(new RefSpec(s"refs/heads/${form.requestBranch}:refs/pull/${issueId}/head"))
        .call
    }

    // record activity
    recordPullRequestActivity(repository.owner, repository.name, loginUserName, issueId, form.title)

    // call web hook
    callPullRequestWebHook("opened", repository, issueId, context.baseUrl, context.loginAccount.get)

    // notifications
    Notifier().toNotify(repository, issueId, form.content.getOrElse("")){
      Notifier.msgPullRequest(s"${context.baseUrl}/${repository.owner}/${repository.name}/pull/${issueId}")
    }

    redirect(s"/${repository.owner}/${repository.name}/pull/${issueId}")
  })

  /**
   * Checks whether conflict will be caused in merging. Returns true if conflict will be caused.
   */
  private def checkConflict(userName: String, repositoryName: String, branch: String,
                            requestUserName: String, requestRepositoryName: String, requestBranch: String): Boolean = {
    LockUtil.lock(s"${userName}/${repositoryName}"){
      using(Git.open(getRepositoryDir(requestUserName, requestRepositoryName))) { git =>
        val remoteRefName = s"refs/heads/${branch}"
        val tmpRefName = s"refs/merge-check/${userName}/${branch}"
        val refSpec = new RefSpec(s"${remoteRefName}:${tmpRefName}").setForceUpdate(true)
        try {
          // fetch objects from origin repository branch
          git.fetch
             .setRemote(getRepositoryDir(userName, repositoryName).toURI.toString)
             .setRefSpecs(refSpec)
             .call

          // merge conflict check
          val merger = MergeStrategy.RECURSIVE.newMerger(git.getRepository, true)
          val mergeBaseTip = git.getRepository.resolve(s"refs/heads/${requestBranch}")
          val mergeTip = git.getRepository.resolve(tmpRefName)
          try {
            !merger.merge(mergeBaseTip, mergeTip)
          } catch {
            case e: NoMergeBaseException =>  true
          }
        } finally {
          val refUpdate = git.getRepository.updateRef(refSpec.getDestination)
          refUpdate.setForceUpdate(true)
          refUpdate.delete()
        }
      }
    }
  }

  /**
   * Checks whether conflict will be caused in merging within pull request. Returns true if conflict will be caused.
   */
  private def checkConflictInPullRequest(userName: String, repositoryName: String, branch: String,
                                         requestUserName: String, requestRepositoryName: String, requestBranch: String,
                                         issueId: Int): Boolean = {
    LockUtil.lock(s"${userName}/${repositoryName}") {
      using(Git.open(getRepositoryDir(userName, repositoryName))) { git =>
        // merge
        val merger = MergeStrategy.RECURSIVE.newMerger(git.getRepository, true)
        val mergeBaseTip = git.getRepository.resolve(s"refs/heads/${branch}")
        val mergeTip = git.getRepository.resolve(s"refs/pull/${issueId}/head")
        try {
          !merger.merge(mergeBaseTip, mergeTip)
        } catch {
          case e: NoMergeBaseException => true
        }
      }
    }
  }

  /**
   * Parses branch identifier and extracts owner and branch name as tuple.
   *
   * - "owner:branch" to ("owner", "branch")
   * - "branch" to ("defaultOwner", "branch")
   */
  private def parseCompareIdentifie(value: String, defaultOwner: String): (String, String) =
    if(value.contains(':')){
      val array = value.split(":")
      (array(0), array(1))
    } else {
      (defaultOwner, value)
    }

  private 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) =>
        view.helpers.date(commit1.commitTime) == view.helpers.date(commit2.commitTime)
      }

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

      (commits, diffs)
    }

  private def searchPullRequests(userName: Option[String], repository: RepositoryService.RepositoryInfo) =
    defining(repository.owner, repository.name){ case (owner, repoName) =>
      val page       = IssueSearchCondition.page(request)
      val sessionKey = Keys.Session.Pulls(owner, repoName)

      // retrieve search condition
      val condition = session.putAndGet(sessionKey,
        if(request.hasQueryString) IssueSearchCondition(request)
        else session.getAs[IssueSearchCondition](sessionKey).getOrElse(IssueSearchCondition())
      )

      issues.html.list(
        "pulls",
        searchIssue(condition, true, (page - 1) * PullRequestLimit, PullRequestLimit, owner -> repoName),
        page,
        (getCollaborators(owner, repoName) :+ owner).sorted,
        getMilestones(owner, repoName),
        getLabels(owner, repoName),
        countIssue(condition.copy(state = "open"  ), true, owner -> repoName),
        countIssue(condition.copy(state = "closed"), true, owner -> repoName),
        condition,
        repository,
        hasWritePermission(owner, repoName, context.loginAccount))
    }
}