WIP

1 files changed, 227 insertions, 0 deletions

diff --git a/entity/dag/entity_actions.go b/entity/dag/entity_actions.go
new file mode 100644
index 00000000..8dcf91e6
--- /dev/null
+++ b/entity/dag/entity_actions.go
@@ -0,0 +1,227 @@
+package dag
+
+import (
+	"fmt"
+
+	"github.com/pkg/errors"
+
+	"github.com/MichaelMure/git-bug/entity"
+	"github.com/MichaelMure/git-bug/repository"
+)
+
+func ListLocalIds(typename string, repo repository.RepoData) ([]entity.Id, error) {
+	refs, err := repo.ListRefs(fmt.Sprintf("refs/%s/", typename))
+	if err != nil {
+		return nil, err
+	}
+	return entity.RefsToIds(refs), nil
+}
+
+// Fetch retrieve updates from a remote
+// This does not change the local entity state
+func Fetch(def Definition, repo repository.Repo, remote string) (string, error) {
+	// "refs/<entity>/*:refs/remotes/<remote>/<entity>/*"
+	fetchRefSpec := fmt.Sprintf("refs/%s/*:refs/remotes/%s/%s/*",
+		def.namespace, remote, def.namespace)
+
+	return repo.FetchRefs(remote, fetchRefSpec)
+}
+
+// Push update a remote with the local changes
+func Push(def Definition, repo repository.Repo, remote string) (string, error) {
+	// "refs/<entity>/*:refs/<entity>/*"
+	refspec := fmt.Sprintf("refs/%s/*:refs/%s/*",
+		def.namespace, def.namespace)
+
+	return repo.PushRefs(remote, refspec)
+}
+
+// Pull will do a Fetch + MergeAll
+// Contrary to MergeAll, this function will return an error if a merge fail.
+func Pull(def Definition, repo repository.ClockedRepo, remote string) error {
+	_, err := Fetch(def, repo, remote)
+	if err != nil {
+		return err
+	}
+
+	for merge := range MergeAll(def, repo, remote) {
+		if merge.Err != nil {
+			return merge.Err
+		}
+		if merge.Status == entity.MergeStatusInvalid {
+			return errors.Errorf("merge failure: %s", merge.Reason)
+		}
+	}
+
+	return nil
+}
+
+func MergeAll(def Definition, repo repository.ClockedRepo, remote string) <-chan entity.MergeResult {
+	out := make(chan entity.MergeResult)
+
+	// no caching for the merge, we load everything from git even if that means multiple
+	// copy of the same entity in memory. The cache layer will intercept the results to
+	// invalidate entities if necessary.
+
+	go func() {
+		defer close(out)
+
+		remoteRefSpec := fmt.Sprintf("refs/remotes/%s/%s/", remote, def.namespace)
+		remoteRefs, err := repo.ListRefs(remoteRefSpec)
+		if err != nil {
+			out <- entity.MergeResult{Err: err}
+			return
+		}
+
+		for _, remoteRef := range remoteRefs {
+			out <- merge(def, repo, remoteRef)
+		}
+	}()
+
+	return out
+}
+
+func merge(def Definition, repo repository.ClockedRepo, remoteRef string) entity.MergeResult {
+	id := entity.RefToId(remoteRef)
+
+	if err := id.Validate(); err != nil {
+		return entity.NewMergeInvalidStatus(id, errors.Wrap(err, "invalid ref").Error())
+	}
+
+	remoteEntity, err := read(def, repo, remoteRef)
+	if err != nil {
+		return entity.NewMergeInvalidStatus(id,
+			errors.Wrapf(err, "remote %s is not readable", def.typename).Error())
+	}
+
+	// Check for error in remote data
+	if err := remoteEntity.Validate(); err != nil {
+		return entity.NewMergeInvalidStatus(id,
+			errors.Wrapf(err, "remote %s data is invalid", def.typename).Error())
+	}
+
+	localRef := fmt.Sprintf("refs/%s/%s", def.namespace, id.String())
+
+	localExist, err := repo.RefExist(localRef)
+	if err != nil {
+		return entity.NewMergeError(err, id)
+	}
+
+	// the bug is not local yet, simply create the reference
+	if !localExist {
+		err := repo.CopyRef(remoteRef, localRef)
+		if err != nil {
+			return entity.NewMergeError(err, id)
+		}
+
+		return entity.NewMergeStatus(entity.MergeStatusNew, id, remoteEntity)
+	}
+
+	// var updated bool
+	// err = repo.MergeRef(localRef, remoteRef, func() repository.Hash {
+	// 	updated = true
+	//
+	// })
+	// if err != nil {
+	// 	return entity.NewMergeError(err, id)
+	// }
+	//
+	// if updated {
+	// 	return entity.NewMergeStatus(entity.MergeStatusUpdated, id, )
+	// } else {
+	// 	return entity.NewMergeStatus(entity.MergeStatusNothing, id, )
+	// }
+
+	localCommit, err := repo.ResolveRef(localRef)
+	if err != nil {
+		return entity.NewMergeError(err, id)
+	}
+
+	remoteCommit, err := repo.ResolveRef(remoteRef)
+	if err != nil {
+		return entity.NewMergeError(err, id)
+	}
+
+	if localCommit == remoteCommit {
+		// nothing to merge
+		return entity.NewMergeStatus(entity.MergeStatusNothing, id, remoteEntity)
+	}
+
+	// fast-forward is possible if otherRef include ref
+
+	remoteCommits, err := repo.ListCommits(remoteRef)
+	if err != nil {
+		return entity.NewMergeError(err, id)
+	}
+
+	fastForwardPossible := false
+	for _, hash := range remoteCommits {
+		if hash == localCommit {
+			fastForwardPossible = true
+			break
+		}
+	}
+
+	if fastForwardPossible {
+		err = repo.UpdateRef(localRef, remoteCommit)
+		if err != nil {
+			return entity.NewMergeError(err, id)
+		}
+		return entity.NewMergeStatus(entity.MergeStatusUpdated, id, remoteEntity)
+	}
+
+	// fast-forward is not possible, we need to create a merge commit
+	// For simplicity when reading and to have clocks that record this change, we store
+	// an empty operationPack.
+	// First step is to collect those clocks.
+
+	localEntity, err := read(def, repo, localRef)
+	if err != nil {
+		return entity.NewMergeError(err, id)
+	}
+
+	// err = localEntity.packClock.Witness(remoteEntity.packClock.Time())
+	// if err != nil {
+	// 	return entity.NewMergeError(err, id)
+	// }
+	//
+	// packTime, err := localEntity.packClock.Increment()
+	// if err != nil {
+	// 	return entity.NewMergeError(err, id)
+	// }
+
+	editTime, err := repo.Increment(fmt.Sprintf(editClockPattern, def.namespace))
+	if err != nil {
+		return entity.NewMergeError(err, id)
+	}
+
+	opp := &operationPack{
+		Operations: nil,
+		CreateTime: 0,
+		EditTime:   editTime,
+		// PackTime:   packTime,
+	}
+
+	treeHash, err := opp.Write(def, repo)
+	if err != nil {
+		return entity.NewMergeError(err, id)
+	}
+
+	// Create the merge commit with two parents
+	newHash, err := repo.StoreCommit(treeHash, localCommit, remoteCommit)
+	if err != nil {
+		return entity.NewMergeError(err, id)
+	}
+
+	// finally update the ref
+	err = repo.UpdateRef(localRef, newHash)
+	if err != nil {
+		return entity.NewMergeError(err, id)
+	}
+
+	return entity.NewMergeStatus(entity.MergeStatusUpdated, id, localEntity)
+}
+
+func Remove() error {
+	panic("")
+}