package uploads

import (
	"context"
	"time"

	"github.com/sourcegraph/sourcegraph/internal/api"
	"github.com/sourcegraph/sourcegraph/internal/codeintel/uploads/internal/commitgraph"
	"github.com/sourcegraph/sourcegraph/internal/codeintel/uploads/internal/lsifstore"
	"github.com/sourcegraph/sourcegraph/internal/codeintel/uploads/internal/store"
	"github.com/sourcegraph/sourcegraph/internal/codeintel/uploads/shared"
	uploadsshared "github.com/sourcegraph/sourcegraph/internal/codeintel/uploads/shared"
	"github.com/sourcegraph/sourcegraph/internal/gitserver"
	"github.com/sourcegraph/sourcegraph/internal/observation"
	"github.com/sourcegraph/sourcegraph/lib/codeintel/precise"
	"github.com/sourcegraph/sourcegraph/lib/errors"
)

type Service struct {
	store           store.Store
	repoStore       RepoStore
	lsifstore       lsifstore.Store
	gitserverClient gitserver.Client
	operations      *operations
}

func newService(
	observationCtx *observation.Context,
	store store.Store,
	repoStore RepoStore,
	lsifstore lsifstore.Store,
	gsc gitserver.Client,
) *Service {
	return &Service{
		store:           store,
		repoStore:       repoStore,
		lsifstore:       lsifstore,
		gitserverClient: gsc,
		operations:      newOperations(observationCtx),
	}
}

func (s *Service) GetCommitsVisibleToUpload(ctx context.Context, uploadID, limit int, token *string) ([]string, *string, error) {
	return s.store.GetCommitsVisibleToUpload(ctx, uploadID, limit, token)
}

func (s *Service) GetCommitGraphMetadata(ctx context.Context, repositoryID int) (bool, *time.Time, error) {
	return s.store.GetCommitGraphMetadata(ctx, repositoryID)
}

func (s *Service) GetDirtyRepositories(ctx context.Context) (_ []shared.DirtyRepository, err error) {
	return s.store.GetDirtyRepositories(ctx)
}

func (s *Service) GetIndexers(ctx context.Context, opts shared.GetIndexersOptions) ([]string, error) {
	return s.store.GetIndexers(ctx, opts)
}

func (s *Service) GetUploads(ctx context.Context, opts shared.GetUploadsOptions) ([]shared.Upload, int, error) {
	return s.store.GetUploads(ctx, opts)
}

func (s *Service) GetUploadByID(ctx context.Context, id int) (shared.Upload, bool, error) {
	return s.store.GetUploadByID(ctx, id)
}

func (s *Service) GetUploadsByIDs(ctx context.Context, ids ...int) ([]shared.Upload, error) {
	return s.store.GetUploadsByIDs(ctx, ids...)
}

func (s *Service) GetUploadIDsWithReferences(ctx context.Context, orderedMonikers []precise.QualifiedMonikerData, ignoreIDs []int, repositoryID int, commit string, limit int, offset int) ([]int, int, int, error) {
	return s.store.GetUploadIDsWithReferences(ctx, orderedMonikers, ignoreIDs, repositoryID, commit, limit, offset, nil)
}

func (s *Service) DeleteUploadByID(ctx context.Context, id int) (bool, error) {
	return s.store.DeleteUploadByID(ctx, id)
}

func (s *Service) DeleteUploads(ctx context.Context, opts shared.DeleteUploadsOptions) error {
	return s.store.DeleteUploads(ctx, opts)
}

func (s *Service) GetRepositoriesMaxStaleAge(ctx context.Context) (_ time.Duration, err error) {
	return s.store.GetRepositoriesMaxStaleAge(ctx)
}

// numAncestors is the number of ancestors to query from gitserver when trying to find the closest
// ancestor we have data for. Setting this value too low (relative to a repository's commit rate)
// will cause requests for an unknown commit return too few results; setting this value too high
// will raise the latency of requests for an unknown commit.
//
// TODO(efritz) - make adjustable via site configuration
const numAncestors = 100

// InferClosestUploads will return the set of visible uploads for the given commit. If this commit is
// newer than our last refresh of the lsif_nearest_uploads table for this repository, then we will mark
// the repository as dirty and quickly approximate the correct set of visible uploads.
//
// Because updating the entire commit graph is a blocking, expensive, and lock-guarded process, we  want
// to only do that in the background and do something chearp in latency-sensitive paths. To construct an
// approximate result, we query gitserver for a (relatively small) set of ancestors for the given commit,
// correlate that with the upload data we have for those commits, and re-run the visibility algorithm over
// the graph. This will not always produce the full set of visible commits - some responses may not contain
// all results while a subsequent request made after the lsif_nearest_uploads has been updated to include
// this commit will.
func (s *Service) InferClosestUploads(ctx context.Context, opts shared.UploadMatchingOptions) (_ []shared.CompletedUpload, err error) {
	ctx, _, endObservation := s.operations.inferClosestUploads.With(ctx, &err, observation.Args{Attrs: opts.Attrs()})
	defer endObservation(1, observation.Args{})

	repo, err := s.repoStore.Get(ctx, api.RepoID(opts.RepositoryID))
	if err != nil {
		return nil, err
	}

	// The parameters exactPath and rootMustEnclosePath align here: if we're looking for completed uploads
	// that can answer queries for a directory (e.g. diagnostics), we want any completed upload that happens
	// to intersect the target directory. If we're looking for completed uploads that can answer queries for
	// a single file, then we need a completed upload with a root that properly encloses that file.
	if uploads, err := s.store.FindClosestCompletedUploads(ctx, opts); err != nil {
		return nil, errors.Wrap(err, "store.FindClosestCompletedUploads")
	} else if len(uploads) != 0 {
		return uploads, nil
	}

	// Repository has no LSIF data at all
	if repositoryExists, err := s.store.HasRepository(ctx, opts.RepositoryID); err != nil {
		return nil, errors.Wrap(err, "dbstore.HasRepository")
	} else if !repositoryExists {
		return nil, nil
	}

	// Commit is known and the empty completed uploads list explicitly means nothing is visible
	if commitExists, err := s.store.HasCommit(ctx, opts.RepositoryID, opts.Commit); err != nil {
		return nil, errors.Wrap(err, "dbstore.HasCommit")
	} else if commitExists {
		return nil, nil
	}

	// Otherwise, the repository has LSIF data but we don't know about the commit. This commit
	// is probably newer than our last upload. Pull back a portion of the updated commit graph
	// and try to link it with what we have in the database. Then mark the repository's commit
	// graph as dirty so it's updated for subsequent requests.

	commits, err := s.gitserverClient.Commits(ctx, repo.Name, gitserver.CommitsOptions{
		Ranges: []string{string(opts.Commit)},
		N:      numAncestors,
		Order:  gitserver.CommitsOrderTopoDate,
	})
	if err != nil {
		return nil, errors.Wrap(err, "gitserverClient.Commits")
	}

	graph := commitgraph.ParseCommitGraph(commits)

	uploads, err := s.store.FindClosestCompletedUploadsFromGraphFragment(ctx, opts, graph)
	if err != nil {
		return nil, errors.Wrap(err, "dbstore.FindClosestCompletedUploadsFromGraphFragment")
	}

	if err := s.store.SetRepositoryAsDirty(ctx, int(opts.RepositoryID)); err != nil {
		return nil, errors.Wrap(err, "dbstore.MarkRepositoryAsDirty")
	}

	return uploads, nil
}

func (s *Service) GetCompletedUploadsWithDefinitionsForMonikers(ctx context.Context, monikers []precise.QualifiedMonikerData) ([]shared.CompletedUpload, error) {
	return s.store.GetCompletedUploadsWithDefinitionsForMonikers(ctx, monikers)
}

func (s *Service) GetCompletedUploadsByIDs(ctx context.Context, ids []int) ([]shared.CompletedUpload, error) {
	return s.store.GetCompletedUploadsByIDs(ctx, ids)
}

func (s *Service) ReferencesForUpload(ctx context.Context, uploadID int) (shared.PackageReferenceScanner, error) {
	return s.store.ReferencesForUpload(ctx, uploadID)
}

func (s *Service) GetAuditLogsForUpload(ctx context.Context, uploadID int) ([]shared.UploadLog, error) {
	return s.store.GetAuditLogsForUpload(ctx, uploadID)
}

// func (s *Service) GetUploadDocumentsForPath(ctx context.Context, bundleID int, pathPattern string) ([]string, int, error) {
// 	return s.lsifstore.GetUploadDocumentsForPath(ctx, bundleID, pathPattern)
// }

func (s *Service) GetRecentUploadsSummary(ctx context.Context, repositoryID int) ([]shared.UploadsWithRepositoryNamespace, error) {
	return s.store.GetRecentUploadsSummary(ctx, repositoryID)
}

func (s *Service) GetLastUploadRetentionScanForRepository(ctx context.Context, repositoryID int) (*time.Time, error) {
	return s.store.GetLastUploadRetentionScanForRepository(ctx, repositoryID)
}

func (s *Service) ReindexUploads(ctx context.Context, opts shared.ReindexUploadsOptions) error {
	return s.store.ReindexUploads(ctx, opts)
}

func (s *Service) ReindexUploadByID(ctx context.Context, id int) error {
	return s.store.ReindexUploadByID(ctx, id)
}

func (s *Service) GetIndexes(ctx context.Context, opts shared.GetIndexesOptions) ([]uploadsshared.AutoIndexJob, int, error) {
	return s.store.GetAutoIndexJobs(ctx, opts)
}

func (s *Service) GetAutoIndexJobByID(ctx context.Context, id int) (uploadsshared.AutoIndexJob, bool, error) {
	return s.store.GetAutoIndexJobByID(ctx, id)
}

func (s *Service) GetAutoIndexJobsByIDs(ctx context.Context, ids ...int) ([]uploadsshared.AutoIndexJob, error) {
	return s.store.GetAutoIndexJobsByIDs(ctx, ids...)
}

func (s *Service) DeleteAutoIndexJobByID(ctx context.Context, id int) (bool, error) {
	return s.store.DeleteAutoIndexJobByID(ctx, id)
}

func (s *Service) DeleteAutoIndexJobs(ctx context.Context, opts shared.DeleteAutoIndexJobsOptions) error {
	return s.store.DeleteAutoIndexJobs(ctx, opts)
}

func (s *Service) SetRerunAutoIndexJobByID(ctx context.Context, id int) error {
	return s.store.SetRerunAutoIndexJobByID(ctx, id)
}

func (s *Service) SetRerunAutoIndexJobs(ctx context.Context, opts shared.SetRerunAutoIndexJobsOptions) error {
	return s.store.SetRerunAutoIndexJobs(ctx, opts)
}

func (s *Service) GetRecentIndexesSummary(ctx context.Context, repositoryID int) ([]uploadsshared.IndexesWithRepositoryNamespace, error) {
	return s.store.GetRecentIndexesSummary(ctx, repositoryID)
}

func (s *Service) NumRepositoriesWithCodeIntelligence(ctx context.Context) (int, error) {
	return s.store.NumRepositoriesWithCodeIntelligence(ctx)
}

func (s *Service) RepositoryIDsWithErrors(ctx context.Context, offset, limit int) ([]uploadsshared.RepositoryWithCount, int, error) {
	return s.store.RepositoryIDsWithErrors(ctx, offset, limit)
}