package main

import (
	"fmt"
	"path"

	"src.opensuse.org/autogits/common"
	"src.opensuse.org/autogits/common/gitea-generated/models"
)

const (
	ListenAddr = "[::1]:8001"

	GitAuthor = "GiteaBot - AutoStaging"
	PrReview  = "pr-review"
)

func processPullRequestClosed(h *common.RequestHandler) error {
	return nil
}

func processPrjGitPullRequestSync(h *common.RequestHandler) error {
	//	req := h.Data.(*common.PullRequestAction)

	return nil
}

func prGitBranchNameForPR(req *common.PullRequestAction) string {
	return fmt.Sprintf("PR_%s#%d", req.Repository.Name, req.Pull_Request.Number)
}

func updateOrCreatePRBranch(h *common.RequestHandler, prjGit *models.Repository, commitMsg, branchName string) {
	req := h.Data.(*common.PullRequestAction)

	h.GitExec("", "clone", "--depth", "1", prjGit.SSHURL, common.DefaultGitPrj)
	h.GitExec(common.DefaultGitPrj, "checkout", "-B", branchName, prjGit.DefaultBranch)
	h.GitExec(common.DefaultGitPrj, "submodule", "update", "--init", "--checkout", "--depth", "1", req.Repository.Name)
	h.GitExec(path.Join(common.DefaultGitPrj, req.Repository.Name), "fetch", "--depth", "1", "origin", req.Pull_Request.Head.Sha)
	h.GitExec(path.Join(common.DefaultGitPrj, req.Repository.Name), "checkout", req.Pull_Request.Head.Sha)
	h.GitExec(common.DefaultGitPrj, "commit", "-a", "-m", commitMsg)
	h.GitExec(common.DefaultGitPrj, "push", "-f", "origin", branchName)
}

func processPullRequestSync(h *common.RequestHandler) error {
	req := h.Data.(*common.PullRequestAction)

	if req.Repository.Name == common.DefaultGitPrj {
		return processPrjGitPullRequestSync(h)
	}

	// need to verify that submodule in the PR for prjgit
	// is still pointing to the HEAD of the PR
	prjPr := h.GetAssociatedPrjGitPR(req)

	h.GitExec("", "clone", "--branch", prjPr.Head.Name, "--depth", "1", prjPr.Head.Repo.SSHURL, common.DefaultGitPrj)
	commitId, ok := h.GitSubmoduleCommitId(common.DefaultGitPrj, req.Repository.Name, prjPr.Head.Ref)

	if !ok {
		return fmt.Errorf("Cannot fetch submodule commit id in prjgit for '%s'", req.Repository.Name)
	}

	// nothing changed, still in sync
	if commitId == req.Pull_Request.Head.Ref {
		return nil
	}

	commitMsg := fmt.Sprintf(`Sync PR

Update to %s`, req.Pull_Request.Head.Sha)

	// we need to update prjgit PR with the new head hash
	branchName := prGitBranchNameForPR(req)
	updateOrCreatePRBranch(h, prjPr.Base.Repo, commitMsg, branchName)

	return h.Error
}

func processPullRequestOpened(h *common.RequestHandler) error {
	req := h.Data.(*common.PullRequestAction)

	// requests against project are not handled here
	if req.Repository.Name == common.DefaultGitPrj {
		return nil
	}

	// create PrjGit branch for buidling the pull request
	branchName := prGitBranchNameForPR(req)
	commitMsg := fmt.Sprintf(`auto-created for %s

This commit was autocreated by %s
referencing

PullRequest: %s/%s#%d`, req.Repository.Owner.Username,
		req.Repository.Name, GitAuthor, req.Repository.Name, req.Pull_Request.Number)

	prjGit := h.CreateRepositoryIfNotExist(*req.Repository.Owner, common.DefaultGitPrj)
	if h.HasError() {
		return h.Error
	}

	updateOrCreatePRBranch(h, prjGit, commitMsg, branchName)

	PR := h.CreatePullRequest(prjGit, branchName, prjGit.DefaultBranch,
		fmt.Sprintf("Forwarded PR: %s", req.Repository.Name),
		fmt.Sprintf(`This is a forwarded pull request by %s
referencing the following pull request:

`+common.PrPattern,
			GitAuthor, req.Repository.Owner.Username, req.Repository.Name, req.Pull_Request.Number),
	)

	if h.HasError() {
		return h.Error
	}

	// request build review
	h.RequestReviews(PR, common.Bot_BuildReview)

	return h.Error
}

func processPullRequest(h *common.RequestHandler) error {
	req := h.Data.(*common.PullRequestAction)

	switch req.Action {
	case "opened":
		return processPullRequestOpened(h)
	case "synchronized":
		return processPullRequestSync(h)
	case "edited":
		// not need to be handled??
		return nil
	case "closed":
		return processPullRequestClosed(h)
	}

	return fmt.Errorf("Unhandled pull request action: %s", req.Action)
}

func main() {
	var defs common.ListenDefinitions

	defs.Url = PrReview
	defs.GitAuthor = GitAuthor

	defs.Handlers = make(map[string]common.RequestProcessor)
	defs.Handlers[common.RequestType_PR] = processPullRequest
	defs.Handlers[common.RequestType_PR_sync] = processPullRequest

	common.RequireGiteaSecretToken()
	common.RequireObsSecretToken()
	common.StartServerWithAddress(defs, ListenAddr)
}