package skate

import (
	"fmt"
	"regexp"
	"strconv"
	"strings"
	"sync"

	"git.archive.org/martin/cgraph/skate/isbn"
	"git.archive.org/martin/cgraph/skate/set"
)

var (
	isbn10Regex = regexp.MustCompile(`[O0-9xX -]{10,18}`)
	isbn13Regex = regexp.MustCompile(`9[O0-9xX -]{12,20}`)

	rune16pool = sync.Pool{
		New: func() interface{} {
			return make([]rune, 0, 16)
		},
	}
	setPool = sync.Pool{
		New: func() interface{} {
			return set.New()
		},
	}
)

// RefToRelease converts a ref to a release. Set a extra.skate.status flag to
// be able to distinguish converted entities later.
func RefToRelease(ref *Ref) (*Release, error) {
	var (
		release  Release
		b        = ref.Biblio
		contribs = make([]struct {
			Index   int    `json:"index,omitempty"`
			RawName string `json:"raw_name,omitempty"`
			Role    string `json:"role,omitempty"`
		}, len(b.ContribRawNames))
	)
	release.Ident = ref.ReleaseIdent
	release.WorkID = ref.WorkIdent
	release.ExtIDs.Arxiv = b.ArxivId
	release.ExtIDs.DOI = b.DOI
	release.ExtIDs.PMID = b.PMID
	release.ExtIDs.PMCID = b.PMCID
	release.Title = b.Title
	release.Publisher = b.Publisher
	release.ContainerName = b.ContainerName
	release.Volume = b.Volume
	release.Issue = b.Issue
	release.Pages = b.Pages
	if ref.ReleaseYear > 1000 {
		release.ReleaseYearValue = fmt.Sprintf("%d", ref.ReleaseYear)
	}
	for i, name := range b.ContribRawNames {
		contribs[i].Index = i
		contribs[i].RawName = name
	}
	release.Contribs = contribs
	if strings.Contains(strings.ToLower(ref.Biblio.Unstructured), "isbn") {
		release.ExtIDs.ISBN = parseIsbn(ref.Biblio.Unstructured)
	}
	return &release, nil
}

// parseIsbn tries to find and validate ISBN from unstructured data.
func parseIsbn(s string) []string {
	// ISBN: 10: 0137822693, pp: 373
	// Robotec, E. (1996). Scorbot ER VII, User's Manual, Eshed Robotec,
	// ISBN9652910333. Shannon, C. (1948). A Mathematical Theory of
	// Communication. The Bell System Technical Journal. July; October,
	// Vol. 27, pp. 379-423; 623-656.
	// Artech House, ISBN: 978-1-60807-201-9, 2011.
	// ...
	var (
		candidates10 = isbn10Regex.FindAllString(s, -1)
		candidates13 = isbn13Regex.FindAllString(s, -1)
		u            []rune
		z            string
	)
	valid := setPool.Get().(set.Set)
	valid.Clear()
	defer setPool.Put(valid)
	for _, v := range append(candidates10, candidates13...) {
		u = rune16pool.Get().([]rune)
		u = u[:0]
		for _, c := range v {
			if c == 'O' {
				c = '0'
			}
			if c >= '0' && c <= '9' || c == 'x' || c == 'X' {
				u = append(u, c)
			}
		}
		z = string(u)
		rune16pool.Put(u)
		if !isbn.Validate(z) {
			continue
		}
		if len(z) < 12 {
			w, err := isbn.To13(z)
			if err != nil {
				continue
			}
			valid.Add(w)
		} else {
			valid.Add(z)
		}
	}
	return valid.Slice()
}

// Ref is a reference document, can be very partial.
type Ref struct {
	Biblio struct {
		ArxivId         string   `json:"arxiv_id,omitempty"`
		ContainerName   string   `json:"container_name,omitempty"`
		ContribRawNames []string `json:"contrib_raw_names,omitempty"`
		DOI             string   `json:"doi,omitempty"`
		Issue           string   `json:"issue,omitempty"`
		PMCID           string   `json:"pmcid,omitempty"`
		PMID            string   `json:"pmid,omitempty"`
		Pages           string   `json:"pages,omitempty"`
		Publisher       string   `json:"publisher,omitempty"`
		Title           string   `json:"title,omitempty"`
		Unstructured    string   `json:"unstructured,omitempty"`
		Url             string   `json:"url,omitempty"`
		Volume          string   `json:"volume,omitempty"`
		Year            int64    `json:"year,omitempty"`
	} `json:"biblio"`
	Index        int64  `json:"index,omitempty"`
	Key          string `json:"key,omitempty"`
	RefSource    string `json:"ref_source,omitempty"`
	ReleaseYear  int    `json:"release_year,omitempty"`
	ReleaseIdent string `json:"release_ident,omitempty"`
	ReleaseStage string `json:"release_stage,omitempty"`
	WorkIdent    string `json:"work_ident,omitempty"`
}

// Release document. Note that we may have varying types for some fields.
// Mitigation for now is to make the field an interface{}, name the field
// "...Value" and to add a method with the field name, doing type assertion.
// Example: ReleaseYearValue interface{}, ReleaseYear() int, etc.
type Release struct {
	ContainerID   string `json:"container_id,omitempty"`
	ContainerName string `json:"container_name,omitempty"`
	Contribs      []struct {
		Index   int    `json:"index,omitempty"`
		RawName string `json:"raw_name,omitempty"`
		Role    string `json:"role,omitempty"`
	} `json:"contribs,omitempty"`
	ExtIDs struct {
		Arxiv       string   `json:"arxiv,omitempty"`
		Core        string   `json:"core,omitempty"`
		DOI         string   `json:"doi,omitempty"`
		ISBN        []string `json:"isbn,omitempty"` // should be isbn13
		Jstor       string   `json:"jstor,omitempty"`
		OLID        string   `json:"olid,omitempty"`
		PMCID       string   `json:"pmcid,omitempty"`
		PMID        string   `json:"pmid,omitempty"`
		WikidataQID string   `json:"wikidata_qid,omitempty"`
	} `json:"ext_ids,omitempty"`
	Ident     string `json:"ident,omitempty"`
	Publisher string `json:"publisher,omitempty"`
	Refs      []struct {
		ContainerName string `json:"container_name,omitempty"`
		Extra         struct {
			DOI     string   `json:"doi,omitempty"`
			Authors []string `json:"authors,omitempty"`
			Key     string   `json:"key,omitempty"`
			Year    string   `json:"year,omitempty"`
			Locator string   `json:"locator,omitempty"`
			Volume  string   `json:"volume,omitempty"`
		} `json:"extra"`
		Index   int64  `json:"index,omitempty"`
		Key     string `json:"key,omitempty"`
		Locator string `json:"locator,omitempty"`
		Year    int64  `json:"year,omitempty"`
	} `json:"refs,omitempty"`
	ReleaseDate      string      `json:"release_date,omitempty"`
	ReleaseYearValue interface{} `json:"release_year,omitempty"` // might be int or str
	ReleaseStage     string      `json:"release_stage,omitempty"`
	ReleaseType      string      `json:"release_type,omitempty"`
	Issue            string      `json:"issue,omitempty"`
	Volume           string      `json:"volume,omitempty"`
	Pages            string      `json:"pages,omitempty"`
	Title            string      `json:"title,omitempty"`
	WorkID           string      `json:"work_id,omitempty"`
	Extra            struct {
		ContainerName string      `json:"container_name,omitempty"`
		SubtitleValue interface{} `json:"subtitle,omitempty"` // []str or str
		Crossref      struct {
			Type string `json:"type,omitempty"`
		} `json:"crossref,omitempty"`
		DataCite struct {
			MetadataVersion int                `json:"metadataVersion,omitempty"`
			Relations       []DataCiteRelation `json:"relations,omitempty"`
		} `json:"datacite,omitempty"`
		Skate struct {
			// Mark as converted (e.g. by setting status to "ref")
			Status string `json:"status,omitempty"`
			// Carry the ref index and key around.
			Ref struct {
				Index   int64  `json:"index,omitempty"`
				Key     string `json:"key,omitempty"`
				Locator string `json:"locator,omitempty"`
			} `json:"ref,omitempty"`
			ResearchGate struct {
				URL string `json:"url,omitempty"`
			} `json:"rg,omitempty"`
		} `json:"skate,omitempty"`
		OpenLibrary struct {
			HasFulltext bool `json:"has_fulltext,omitempty"`
		} `json:"ol,omitempty"`
	} `json:"extra,omitempty"`
}

// Subtitle returns a slice of subtitle strings.
func (r *Release) Subtitle() (result []string) {
	switch v := r.Extra.SubtitleValue.(type) {
	case []interface{}:
		for _, e := range v {
			result = append(result, fmt.Sprintf("%v", e))
		}
		return result
	case []string:
		return v
	case string:
		return []string{v}
	}
	return []string{}
}

// ReleaseYearString returns release year as string.
func (r *Release) ReleaseYearString() string {
	return fmt.Sprintf("%d", r.ReleaseYear())
}

// ReleaseYear returns year as int, no further validity checks.
func (r *Release) ReleaseYear() int {
	switch v := r.ReleaseYearValue.(type) {
	case int:
		return v
	case float64:
		return int(v)
	case string:
		w, err := strconv.Atoi(v)
		if err != nil {
			return 0
		}
		return w
	default:
		return 0
	}
}

// DataCiteRelation as it appears in the release extra field.
type DataCiteRelation struct {
	RelatedIdentifierType  string      `json:"relatedIdentifierType,omitempty"`
	RelatedIdentifierValue interface{} `json:"relatedIdentifier,omitempty"`
}

// RelatedIdentifier returns the identifier as string.
func (r *DataCiteRelation) RelatedIdentifier() string {
	switch v := r.RelatedIdentifierValue.(type) {
	case string:
		return v
	default:
		return fmt.Sprintf("%v", v)
	}
}

// Sitemap basic JSON style, e.g. for https://archive.org/details/rg_sitemap_2021_02_23.
type Sitemap struct {
	Lastmod string `json:"lastmod,omitempty"`
	Title   string `json:"title,omitempty"`
	URL     string `json:"url,omitempty"`
}

// BiblioRef as a prototype for indexing, https://is.gd/yicTom.
type BiblioRef struct {
	Key                    string `json:"_id,omitempty"`
	IndexedTs              string `json:"indexed_ts,omitempty"` // https://www.elastic.co/guide/en/elasticsearch/reference/current/date.html
	SourceReleaseIdent     string `json:"source_release_ident,omitempty"`
	SourceWorkIdent        string `json:"source_work_ident,omitempty"`
	SourceWikipediaArticle string `json:"source_wikipedia_article,omitempty"`
	SourceReleaseStage     string `json:"source_release_stage,omitempty"`
	SourceYear             string `json:"source_year,omitempty"`
	RefIndex               int64  `json:"ref_index,omitempty"` // 1-based
	RefKey                 string `json:"ref_key,omitempty"`
	RefLocator             string `json:"ref_locator,omitempty"`
	TargetReleaseIdent     string `json:"target_release_ident,omitempty"`
	TargetWorkIdent        string `json:"target_work_ident,omitempty"`
	TargetOpenLibraryWork  string `json:"target_openlibrary_work,omitempty"`
	TargetURLSurt          string `json:"target_url_surt,omitempty"`
	TargetURL              string `json:"target_url,omitempty"`
	MatchProvenance        string `json:"match_provenance,omitempty"`
	MatchStatus            string `json:"match_status,omitempty"`
	MatchReason            string `json:"match_reason,omitempty"`
	TargetUnstructured     string `json:"target_unstructured,omitempty"`
	TargetCSL              string `json:"target_csl,omitempty"`
}

// ReleaseCluster, a list of match candidates. This is typically serialized as a
// single JSON line.
type ReleaseCluster struct {
	Key    string     `json:"k"`
	Values []*Release `json:"v"`
}

// OneNonRef returns the first non-reference release found in a cluster, or an
// error, if none has been found. This depends on converted references setting
// extra.skate.status to "ref" - we use this in mixed clusters (catalog entries
// and references converted into releases).
func (rc *ReleaseCluster) OneNonRef() (*Release, error) {
	for _, re := range rc.Values {
		if re.Extra.Skate.Status != "ref" {
			return re, nil
		}
	}
	return nil, fmt.Errorf("no reference/release found for cluster key: %v", rc.Key)
}

// MinimalCitations variant from archive.org/details/wikipedia_citations_2020-07-14.
type MinimalCitations struct {
	IDList         string `json:"ID_list"`
	PageTitle      string `json:"page_title"`
	Title          string `json:"Title"`
	TypeOfCitation string `json:"type_of_citation"`
}

// IDList with commonly used identifier from wikipedia citations.
type IDList struct {
	ISBN  string `json:"isbn,omitempty"`
	DOI   string `json:"doi,omitempty"`
	PMID  string `json:"pmid,omitempty"`
	ISSN  string `json:"issn,omitempty"`
	JSTOR string `json:"jstor,omitempty"`
	PMC   string `json:"pmc,omitempty"`
	ARXIV string `json:"arxiv,omitempty"`
	OL    string `json:"ol,omitempty"`
}

// IsZero returns true, if none of the identifiers is defined.
func (l *IDList) IsZero() bool {
	return *l == IDList{}
}

// ParseIDList parses out the identifiers from a citation document, the IDList
// values look something like this: "{BIBCODE=1992ApJ...399L..31C,
// DOI=10.1086/186599}".
func (c *MinimalCitations) ParseIDList() (result IDList) {
	if len(c.IDList) < 3 {
		return result
	}
	var (
		s     = c.IDList[1 : len(c.IDList)-1] // get rid of "{" and "}"
		parts = strings.Split(s, ",")
		pair  []string
	)
	for _, part := range parts {
		pair = strings.Split(part, "=")
		if len(pair) != 2 {
			continue
		}
		pair[0] = strings.TrimSpace(pair[0])
		pair[1] = strings.TrimSpace(pair[1])
		switch pair[0] {
		case "ISBN":
			result.ISBN = pair[1]
		case "DOI":
			result.DOI = pair[1]
		case "PMID":
			result.PMID = pair[1]
		case "ISSN":
			result.ISSN = pair[1]
		case "PMC":
			result.PMC = pair[1]
		case "JSTOR":
			result.JSTOR = pair[1]
		case "ARXIV":
			result.ARXIV = pair[1]
		case "OL":
			result.OL = pair[1]
		default:
			continue
		}
	}
	return result
}

// OpenLibraryWork from data dump (solr).
type OpenLibraryWork struct {
	AuthorFacet      []string `json:"author_facet"`
	AuthorKey        []string `json:"author_key"`
	AuthorName       []string `json:"author_name"`
	CoverEditionKey  string   `json:"cover_edition_key"`
	CoverI           int64    `json:"cover_i"`
	EbookCountI      int64    `json:"ebook_count_i"`
	EditionCount     int64    `json:"edition_count"`
	EditionKey       []string `json:"edition_key"`
	FirstPublishYear int64    `json:"first_publish_year"`
	HasFulltext      bool     `json:"has_fulltext"`
	IdGoodreads      []string `json:"id_goodreads"`
	IdLibrarything   []string `json:"id_librarything"`
	Isbn             []string `json:"isbn"`
	Key              string   `json:"key"`
	Language         []string `json:"language"`
	LastModifiedI    int64    `json:"last_modified_i"`
	PublishDate      []string `json:"publish_date"`
	PublishYear      []int64  `json:"publish_year"`
	Publisher        []string `json:"publisher"`
	PublisherFacet   []string `json:"publisher_facet"`
	Seed             []string `json:"seed"`
	Text             []string `json:"text"`
	Title            string   `json:"title"`
	TitleSuggest     []string `json:"title_suggest"`
	Type             string   `json:"type"`
	Version          int64    `json:"_version_"`
}

// OpenLibraryToRelease convert OL data into a release. XXX: release/work?
func OpenLibraryToRelease(w *OpenLibraryWork) (*Release, error) {
	var (
		release  Release
		contribs = make([]struct {
			Index   int    `json:"index,omitempty"`
			RawName string `json:"raw_name,omitempty"`
			Role    string `json:"role,omitempty"`
		}, len(w.AuthorName))
		s = set.New()
	)
	for i, author := range w.AuthorName {
		contribs[i].RawName = author
	}
	release.Title = w.Title
	if len(w.PublishYear) > 0 {
		release.ReleaseYearValue = w.FirstPublishYear
	}
	for _, v := range w.Isbn {
		switch {
		case len(v) < 13:
			if w, err := isbn.To13(v); err == nil {
				s.Add(w)
			}
		default:
			s.Add(v)
		}
	}
	if len(w.Publisher) > 0 {
		release.Publisher = w.Publisher[0]
	}
	release.ExtIDs.ISBN = s.Slice()
	release.ExtIDs.OLID = strings.Replace(w.Key, "/works/", "", 1)
	release.Extra.OpenLibrary.HasFulltext = w.HasFulltext
	return &release, nil
}