package source

import (
	"context"
	"fmt"
	"strconv"
	"strings"

	dvpb "code.hackerspace.pl/hscloud/devtools/depotview/proto"
)

type DepotViewSourceProvider struct {
	stub dvpb.DepotViewClient
}

func NewDepotView(stub dvpb.DepotViewClient) SourceProvider {
	return &DepotViewSourceProvider{
		stub: stub,
	}
}

func changeRef(ref string) int64 {
	ref = strings.ToLower(ref)
	if !strings.HasPrefix(ref, "change/") && !strings.HasPrefix(ref, "cr/") {
		return 0
	}
	n, err := strconv.ParseInt(strings.SplitN(ref, "/", 2)[1], 10, 64)
	if err != nil {
		return 0
	}

	return n
}

func (s *DepotViewSourceProvider) Source(ctx context.Context, ref string) (Source, error) {
	var hash string
	n := changeRef(ref)
	if n != 0 {
		res, err := s.stub.ResolveGerritChange(ctx, &dvpb.ResolveGerritChangeRequest{Change: n})
		if err != nil {
			return nil, err
		}
		hash = res.Hash
	} else {
		res, err := s.stub.Resolve(ctx, &dvpb.ResolveRequest{Ref: ref})
		if err != nil {
			return nil, err
		}
		hash = res.Hash
	}

	if hash == "" {
		return nil, nil
	}

	return &depotViewSource{
		stub:   s.stub,
		hash:   hash,
		change: n,
	}, nil
}

type depotViewSource struct {
	stub   dvpb.DepotViewClient
	hash   string
	change int64
}

func (s *depotViewSource) IsFile(ctx context.Context, path string) (bool, error) {
	res, err := s.stub.Stat(ctx, &dvpb.StatRequest{
		Hash: s.hash,
		Path: path,
	})
	if err != nil {
		return false, err
	}
	return res.Type == dvpb.StatResponse_TYPE_FILE, nil
}

func (s *depotViewSource) IsDirectory(ctx context.Context, path string) (bool, error) {
	res, err := s.stub.Stat(ctx, &dvpb.StatRequest{
		Hash: s.hash,
		Path: path,
	})
	if err != nil {
		return false, err
	}
	return res.Type == dvpb.StatResponse_TYPE_DIRECTORY, nil
}

func (s *depotViewSource) ReadFile(ctx context.Context, path string) ([]byte, error) {
	var data []byte
	srv, err := s.stub.Read(ctx, &dvpb.ReadRequest{
		Hash: s.hash,
		Path: path,
	})
	if err != nil {
		return nil, err
	}
	for {
		res, err := srv.Recv()
		if err != nil {
			return nil, err
		}
		if len(res.Data) == 0 {
			break
		}
		data = append(data, res.Data...)
	}
	return data, nil
}

func (s *depotViewSource) WebLinks(fpath string) []WebLink {
	gitURL := fmt.Sprintf(FlagGitwebURLPattern, s.hash, fpath)
	links := []WebLink{
		WebLink{Kind: "source", LinkLabel: s.hash[:16], LinkURL: gitURL},
	}

	if s.change != 0 {
		gerritLabel := fmt.Sprintf("change %d", s.change)
		gerritLink := fmt.Sprintf("https://gerrit.hackerspace.pl/%d", s.change)
		links = append(links, WebLink{Kind: "gerrit", LinkLabel: gerritLabel, LinkURL: gerritLink})
	}

	return links
}