// Copyright 2017 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package main

import (
	"context"
	"errors"

	"golang.org/x/build/maintner"
	"golang.org/x/build/maintner/maintnerd/apipb"
)

// apiService implements apipb.MaintnerServiceServer using the Corpus c.
type apiService struct {
	c *maintner.Corpus
}

func (s apiService) HasAncestor(ctx context.Context, req *apipb.HasAncestorRequest) (*apipb.HasAncestorResponse, error) {
	if len(req.Commit) != 40 {
		return nil, errors.New("invalid Commit")
	}
	if len(req.Ancestor) != 40 {
		return nil, errors.New("invalid Ancestor")
	}
	s.c.RLock()
	defer s.c.RUnlock()

	commit := s.c.GitCommit(req.Commit)
	res := new(apipb.HasAncestorResponse)
	if commit == nil {
		// TODO: wait for it? kick off a fetch of it and then answer?
		// optional?
		res.UnknownCommit = true
		return res, nil
	}
	if a := s.c.GitCommit(req.Ancestor); a != nil {
		res.HasAncestor = commit.HasAncestor(a)
	}
	return res, nil
}