method.go

package getdoc

import (
	"fmt"
	"io"
	"strconv"
	"strings"

	"github.com/PuerkitoBio/goquery"
)

// Method represents method documentation.
type Method struct {
	Name        string                      `json:"name"`
	Description []string                    `json:"description,omitempty"`
	Links       []string                    `json:"links,omitempty"`
	Parameters  map[string]ParamDescription `json:"parameters,omitempty"`
	Errors      []Error                     `json:"errors,omitempty"`
	BotCanUse   bool                        `json:"bot_can_use,omitempty"`
}

// Error represent possible error documentation.
type Error struct {
	Code        int    `json:"code"`
	Type        string `json:"type"`
	Description string `json:"description,omitempty"`
}

func docBotCanUser(doc *goquery.Document) bool {
	return doc.Find("#bots-can-use-this-method").Length() > 0
}

// docErrors extract error code documentation from document.
func docErrors(doc *goquery.Document) []Error {
	var output []Error

	docTableAfterFunc(doc, func(s *goquery.Selection) bool {
		return s.Find("#possible-errors").Length() > 0 ||
			// Some pages have no such selector, so we try to detect "Possible errors" header by text.
			//
			// TODO(tdakkota): try to parse attributes
			strings.HasPrefix(s.Text(), "Possible errors")
	}).Each(func(i int, row *goquery.Selection) {
		var rowContents []string
		row.Find("td").Each(func(i int, column *goquery.Selection) {
			rowContents = append(rowContents, column.Text())
		})
		if len(rowContents) != 3 {
			return
		}
		code, err := strconv.Atoi(rowContents[0])
		if err != nil {
			return
		}
		e := Error{
			Code:        code,
			Type:        strings.TrimSpace(rowContents[1]),
			Description: strings.TrimSpace(rowContents[2]),
		}
		output = append(output, e)
	})
	return output
}

// ParseMethod extracts method documentation from reader.
func ParseMethod(reader io.Reader) (*Method, error) {
	doc, err := goquery.NewDocumentFromReader(reader)
	if err != nil {
		return nil, fmt.Errorf("failed to parse document: %w", err)
	}

	desc, links := docDescription(doc)
	return &Method{
		Name:        docTitle(doc),
		Description: desc,
		Links:       links,
		Parameters:  docParams(doc),
		Errors:      docErrors(doc),
		BotCanUse:   docBotCanUser(doc),
	}, nil
}