// skate-conv converts various schemas into releases. This should replace the
// very specific skate-ref-to-release and the like.
//
// $ skate-conv -f ref < FILE > FILE
//
// Currently source schemas: "ref", "ol", "rg"
package main

import (
	"flag"
	"log"
	"os"
	"runtime"
	"strings"

	"git.archive.org/martin/cgraph/skate"
	"git.archive.org/martin/cgraph/skate/parallel"
	json "github.com/segmentio/encoding/json"
)

var (
	numWorkers = flag.Int("w", runtime.NumCPU(), "number of workers")
	batchSize  = flag.Int("b", 100000, "batch size")
	fromFormat = flag.String("f", "ref", "import schema: ref, rg, ol")

	f func([]byte) ([]byte, error) // our converter function
)

func main() {
	flag.Parse()
	switch *fromFormat {
	case "ref":
		f = refToRelease
	case "rg":
		f = rgSitemapToRelease
	case "ol":
		f = openLibraryToRelease
	default:
		log.Fatalf("unsupported input schema: %v", *fromFormat)
	}
	pp := parallel.NewProcessor(os.Stdin, os.Stdout, f)
	pp.NumWorkers = *numWorkers
	pp.BatchSize = *batchSize
	if err := pp.Run(); err != nil {
		log.Fatal(err)
	}
}

// refToRelease converts a ref document to a release. The standard conversion
// plus some extra fields.
func refToRelease(p []byte) ([]byte, error) {
	var (
		ref     skate.Ref
		release *skate.Release
		err     error
	)
	if err = json.Unmarshal(p, &ref); err != nil {
		return nil, err
	}
	if release, err = skate.RefToRelease(&ref); err != nil {
		return nil, err
	}
	release.Extra.Skate.Status = "ref" // means: converted from ref
	release.Extra.Skate.Ref.Index = ref.Index
	release.Extra.Skate.Ref.Key = ref.Key
	return skate.JsonMarshalNewline(release)
}

// rgSitemapToRelease converts a simple sitemap to a release entity, e.g. from
// https://archive.org/download/rg_sitemap_2021_02_23/rg_sitemap_2021_02_23.ndj.zst.
func rgSitemapToRelease(p []byte) ([]byte, error) {
	var (
		s       skate.Sitemap
		release skate.Release
		err     error
	)
	if err = json.Unmarshal(p, &s); err != nil {
		return nil, err
	}
	release.Title = s.Title
	if len(s.URL) > 41 {
		// A pseudo ident, maybe irritating; we want the "321885388".
		// https://www.researchgate.net/publication/321885388_We_came_here_on_dif
		release.Ident = strings.Split(s.URL[41:], "_")[0]
	}
	release.Extra.Skate.Status = "rg"
	release.Extra.Skate.ResearchGate.URL = s.URL
	return skate.JsonMarshalNewline(release)
}

// openLibraryToRelease converts an Open Library work item to a release.
func openLibraryToRelease(p []byte) ([]byte, error) {
	var (
		w       skate.OpenLibraryWork
		release *skate.Release
		err     error
	)
	if err = json.Unmarshal(p, &w); err != nil {
		return nil, err
	}
	if release, err = skate.OpenLibraryWorkToRelease(&w); err != nil {
		return nil, err
	}
	release.Extra.Skate.Status = "ol"
	return skate.JsonMarshalNewline(release)
}