text

type Chunk struct {
	Page    int    // from 1
	Ordinal int    // position in the paper, from 0
	Section string // SectionReferences, or "" for the body
	// Start and End are byte offsets of Text in its page's cleaned text, so
	// a passage can be found again in its page and its neighbours stitched
	// back on.
	Start, End int
	Text       string
}

type Clue struct {
	ID    identity.ID
	Where string // in words: "the arXiv stamp", "a DOI label on page 1", …
}

type Extractor interface {
	Extract(ctx context.Context, pdf []byte) ([]string, error)
}

type Front struct {
	// Pages is the cleaned text of the first pages, at most frontPages.
	Pages []string
	// Meta is the document information dictionary, where present: Title,
	// Subject, Keywords, and the doi key some publishers add. Templates
	// reuse old values, so it is a clue, never an answer.
	Meta map[string]string
	// Title is the largest text near the top of page 1 — the title, usually,
	// but a journal's name or a running head sometimes. A candidate only.
	Title string
}

type FrontReader interface {
	Front(ctx context.Context, pdf []byte) (Front, error)
}

type Mention struct {
	Ref        string // Ref.ID
	Page       int    // from 1
	Start, End int    // byte offsets of Sentence in its page's cleaned text
	Sentence   string
	Section    string // a heading's name above it, or ""
	Marker     string // as printed
	Method     string // MethodNumeric or MethodAuthorYear
	Confidence float64
}

type PDFium struct {
	// contains filtered or unexported fields
}

type Ref struct {
	ID      string // the cited work's fil ID
	Title   string
	Year    int
	DOI     string
	Surname string // first author's
	Authors int    // how many authors; 0 when not known
}

type Result struct {
	Verdict
	Pages  int
	Chars  int     // visible characters, all pages
	Chunks []Chunk // only when Status is ok: gibberish would pollute search
	// Text is the cleaned pages, when Status is ok: what citation context is
	// found in (Contexts), while the PDF is read.
	Text []string
}

type Status string

type Verdict struct {
	Status Status
	Reason string // why, in words, when Status is not ok
}