package diffstore

import (
	context "golang.org/x/net/context"

	"go.skia.org/infra/golden/go/diff"
)

// Generate the go code from the protocol buffer definitions.
//go:generate protoc --go_out=plugins=grpc:. diffservice.proto

const MAX_MESSAGE_SIZE = 100 * 1024 * 1024

// DiffServiceImpl implements DiffServiceServer.
type DiffServiceImpl struct {
	diffStore diff.DiffStore
}

// NewDiffServiceServer implements the server side of the diff service by
// wrapping around a DiffStore, most likely an instance of MemDiffStore.
func NewDiffServiceServer(diffStore diff.DiffStore) DiffServiceServer {
	return &DiffServiceImpl{
		diffStore: diffStore,
	}
}

// GetDiffs wraps around the Get method of the underlying DiffStore.
func (d *DiffServiceImpl) GetDiffs(ctx context.Context, req *GetDiffsRequest) (*GetDiffsResponse, error) {
	diffs, err := d.diffStore.Get(req.Priority, req.MainDigest, req.RightDigests)
	if err != nil {
		return nil, err
	}

	resp := make(map[string]*DiffMetricsResponse, len(diffs))
	for k, metrics := range diffs {
		resp[k] = toDiffMetricsResponse(metrics)
	}

	return &GetDiffsResponse{
		Diffs: resp,
	}, nil
}

// WarmDigests wraps around the WarmDigests method of the underlying DiffStore.
func (d *DiffServiceImpl) WarmDigests(ctx context.Context, req *WarmDigestsRequest) (*Empty, error) {
	d.diffStore.WarmDigests(req.Priority, req.Digests, req.Sync)
	return &Empty{}, nil
}

// WarmDiffs wraps around the WarmDiffs method of the underlying DiffStore.
func (d *DiffServiceImpl) WarmDiffs(ctx context.Context, req *WarmDiffsRequest) (*Empty, error) {
	d.diffStore.WarmDiffs(req.Priority, req.LeftDigests, req.RightDigests)
	return &Empty{}, nil
}

// UnavailableDigests wraps around the UnavailableDigests method of the underlying DiffStore.
func (d *DiffServiceImpl) UnavailableDigests(ctx context.Context, req *Empty) (*UnavailableDigestsResponse, error) {
	unavailable := d.diffStore.UnavailableDigests()
	ret := make(map[string]*DigestFailureResponse, len(unavailable))
	for k, failure := range unavailable {
		ret[k] = &DigestFailureResponse{
			Digest: failure.Digest,
			Reason: string(failure.Reason),
			TS:     failure.TS,
		}
	}
	return &UnavailableDigestsResponse{DigestFailures: ret}, nil
}

// PurgeDigests wraps around the PurgeDigests method of the underlying DiffStore.
func (d *DiffServiceImpl) PurgeDigests(ctx context.Context, req *PurgeDigestsRequest) (*Empty, error) {
	return &Empty{}, d.diffStore.PurgeDigests(req.Digests, req.PurgeGCS)
}

// Ping returns an empty message, used to test the connection.
func (d *DiffServiceImpl) Ping(context.Context, *Empty) (*Empty, error) {
	return &Empty{}, nil
}

// toDiffMetricsResponse converts a diff.DiffMetrics instance to an
// instance of DiffMetricsResponse.
func toDiffMetricsResponse(d *diff.DiffMetrics) *DiffMetricsResponse {
	return &DiffMetricsResponse{
		NumDiffPixels:    int32(d.NumDiffPixels),
		PixelDiffPercent: d.PixelDiffPercent,
		MaxRGBADiffs:     toInt32Slice(d.MaxRGBADiffs),
		DimDiffer:        d.DimDiffer,
		Diffs:            d.Diffs,
	}
}

func toInt32Slice(arr []int) []int32 {
	ret := make([]int32, len(arr))
	for idx, val := range arr {
		ret[idx] = int32(val)
	}
	return ret
}