~repos /gromer

package collection

import (
  "context"
  "fmt"
  "io"
  "reflect"

  "github.com/rotisserie/eris"
  "github.com/rs/zerolog/log"
  "gocloud.dev/docstore"
  _ "gocloud.dev/docstore/gcpfirestore"
)

type Collection[S any] struct {
  *docstore.Collection
  Type reflect.Type
}

func (c *Collection[S]) Query() *Query[S] {
  return &Query[S]{c.Collection.Query(), c}
}

type Query[S any] struct {
  *docstore.Query
  Parent *Collection[S]
}

func (q *Query[S]) Where(fp docstore.FieldPath, op string, value interface{}) *Query[S] {
  return &Query[S]{q.Query.Where(fp, op, value), q.Parent}
}

func (q *Query[S]) Limit(n int) *Query[S] {
  return &Query[S]{q.Query.Limit(n), q.Parent}
}

func (q *Query[S]) OrderBy(field, direction string) *Query[S] {
  return &Query[S]{q.Query.OrderBy(field, direction), q.Parent}
}

func (q *Query[S]) One(ctx context.Context) (S, int, error) {
  results, err := q.All(ctx)
  if err != nil {
    return *new(S), 500, err
  }
  arr := reflect.ValueOf(results)
  if arr.Len() == 0 {
    return *new(S), 404, eris.Errorf("%s not found", q.Parent.Type.Name())
  }
  return arr.Index(0).Interface().(S), 200, nil
}

func (q *Query[S]) All(ctx context.Context) ([]S, error) {
  iter := q.Get(ctx)
  defer iter.Stop()
  results := reflect.New(reflect.SliceOf(reflect.PtrTo(q.Parent.Type))).Elem()
  for {
    v := reflect.New(q.Parent.Type)
    err := iter.Next(ctx, v.Interface())
    if err == io.EOF {
      break
    } else if err != nil {
      return nil, err
    } else {
      results.Set(reflect.Append(results, v))
    }
  }
  return results.Interface().([]S), nil
}

func NewCollection[S any](project, name string, t interface{}) *Collection[S] {
  coll, err := docstore.OpenCollection(context.Background(), fmt.Sprintf("firestore://projects/%s/databases/(default)/documents/%s-%s?name_field=ID", project, project, name))
  if err != nil {
    log.Fatal().Stack().Err(err).Msgf("failed to getTable %s", name)
  }
  return &Collection[S]{coll, reflect.TypeOf(t)}
}