package solver

import (
	"encoding/json"
	"strings"
	"sync"

	"github.com/moby/buildkit/solver/pb"
	"github.com/moby/buildkit/source"
	digest "github.com/opencontainers/go-digest"
	"golang.org/x/net/context"
)

const sourceCacheType = "buildkit.source.v0"

type sourceOp struct {
	mu  sync.Mutex
	op  *pb.Op_Source
	sm  *source.Manager
	src source.SourceInstance
}

func newSourceOp(_ Vertex, op *pb.Op_Source, sm *source.Manager) (Op, error) {
	return &sourceOp{
		op: op,
		sm: sm,
	}, nil
}

func (s *sourceOp) instance(ctx context.Context) (source.SourceInstance, error) {
	s.mu.Lock()
	defer s.mu.Unlock()
	if s.src != nil {
		return s.src, nil
	}
	id, err := source.FromString(s.op.Source.Identifier)
	if err != nil {
		return nil, err
	}
	if id, ok := id.(*source.GitIdentifier); ok {
		for k, v := range s.op.Source.Attrs {
			switch k {
			case pb.AttrKeepGitDir:
				if v == "true" {
					id.KeepGitDir = true
				}
			}
		}
	}
	if id, ok := id.(*source.LocalIdentifier); ok {
		for k, v := range s.op.Source.Attrs {
			switch k {
			case pb.AttrLocalSessionID:
				id.SessionID = v
				if p := strings.SplitN(v, ":", 2); len(p) == 2 {
					id.Name = p[0] + "-" + id.Name
					id.SessionID = p[1]
				}
			case pb.AttrIncludePatterns:
				var patterns []string
				if err := json.Unmarshal([]byte(v), &patterns); err != nil {
					return nil, err
				}
				id.IncludePatterns = patterns
			}
		}
	}
	src, err := s.sm.Resolve(ctx, id)
	if err != nil {
		return nil, err
	}
	s.src = src
	return s.src, nil
}

func (s *sourceOp) CacheKey(ctx context.Context) (digest.Digest, error) {
	src, err := s.instance(ctx)
	if err != nil {
		return "", err
	}
	k, err := src.CacheKey(ctx)
	if err != nil {
		return "", err
	}
	return digest.FromBytes([]byte(sourceCacheType + ":" + k)), nil
}

func (s *sourceOp) Run(ctx context.Context, _ []Reference) ([]Reference, error) {
	src, err := s.instance(ctx)
	if err != nil {
		return nil, err
	}
	ref, err := src.Snapshot(ctx)
	if err != nil {
		return nil, err
	}
	return []Reference{ref}, nil
}

func (s *sourceOp) ContentMask(context.Context) (digest.Digest, [][]string, error) {
	return "", nil, nil
}