package hocr

// TODO: Parse line name to zero pad line numbers, so they can
//       be sorted easily
// TODO: have same filename format as .prob uses, so include base
//       dirname, and don't include line numbers if there's only
//       one line in the hocr

import (
	"encoding/xml"
	"image"
	"image/png"
	"io/ioutil"
	"os"
	"path/filepath"
	"regexp"
	"strconv"
	"strings"

	"git.rescribe.xyz/testingtools/parse"
)

type Hocr struct {
	Lines []OcrLine `xml:"body>div>div>p>span"`
}

type OcrLine struct {
	Class string `xml:"class,attr"`
	Id string `xml:"id,attr"`
	Title string `xml:"title,attr"`
	Words []OcrWord `xml:"span"`
	Text string `xml:",chardata"`
}

type OcrWord struct {
	Class string `xml:"class,attr"`
	Id string `xml:"id,attr"`
	Title string `xml:"title,attr"`
	Chars []OcrChar `xml:"span"`
	Text string `xml:",chardata"`
}

type OcrChar struct {
	Class string `xml:"class,attr"`
	Id string `xml:"id,attr"`
	Title string `xml:"title,attr"`
	Chars []OcrChar `xml:"span"`
	Text string `xml:",chardata"`
}

// Returns the confidence for a word based on its x_wconf value
func wordConf(s string) (float64, error) {
	re, err := regexp.Compile(`x_wconf ([0-9.]+)`)
	if err != nil {
		return 0.0, err
	}
	conf := re.FindStringSubmatch(s)
	return strconv.ParseFloat(conf[1], 64)
}

func boxCoords(s string) ([4]int, error) {
	var coords [4]int
	re, err := regexp.Compile(`bbox ([0-9]+) ([0-9]+) ([0-9]+) ([0-9]+)`)
	if err != nil {
		return coords, err
	}
	coordstr := re.FindStringSubmatch(s)
	for i := range coords {
		c, err := strconv.Atoi(coordstr[i+1])
		if err != nil {
			return coords, err
		}
		coords[i] = c
	}
	return coords, nil
}

func noText(s string) bool {
	t := strings.Trim(s, " \n")
	return len(t) == 0
}

func Parse(b []byte) (Hocr, error) {
	var hocr Hocr

	err := xml.Unmarshal(b, &hocr)
	if err != nil {
		return hocr, err
	}

	return hocr, nil
}

func parseLineDetails(h Hocr, i image.Image, name string) (parse.LineDetails, error) {
	lines := make(parse.LineDetails, 0)

	for _, l := range h.Lines {
		totalconf := float64(0)
		num := 0
		for _, w := range l.Words {
			c, err := wordConf(w.Title)
			if err != nil {
				return lines, err
			}
			num++
			totalconf += c
		}

		coords, err := boxCoords(l.Title)
		if err != nil {
			return lines, err
		}

		var line parse.LineDetail
		line.Name = l.Id
		line.Avgconf = (totalconf/float64(num)) / 100
		linetext := ""

		linetext = l.Text
		if(noText(linetext)) {
			linetext = ""
			for _, w := range l.Words {
				if(w.Class != "ocrx_word") {
					continue
				}
				linetext += w.Text + " "
			}
		}
		if(noText(linetext)) {
			linetext = ""
			for _, w := range l.Words {
				if(w.Class != "ocrx_word") {
					continue
				}
				for _, c := range w.Chars {
					if(c.Class != "ocrx_cinfo") {
						continue
					}
					linetext += c.Text
				}
				linetext += " "
			}
		}
		line.Text = strings.TrimRight(linetext, " ")
		line.Text += "\n"
		line.OcrName = name
		var imgd parse.ImgDirect
		imgd.Img = i.(*image.Gray).SubImage(image.Rect(coords[0], coords[1], coords[2], coords[3]))
		line.Img = imgd
		lines = append(lines, line)
	}
	return lines, nil
}

func GetLineDetails(hocrfn string) (parse.LineDetails, error) {
	var newlines parse.LineDetails

	file, err := ioutil.ReadFile(hocrfn)
	if err != nil {
		return newlines, err
	}

	h, err := Parse(file)
	if err != nil {
		return newlines, err
	}

	pngfn := strings.Replace(hocrfn, ".hocr", ".png", 1)
	pngf, err := os.Open(pngfn)
	if err != nil {
		return newlines, err
	}
	defer pngf.Close()
	img, err := png.Decode(pngf)
	if err != nil {
		return newlines, err
	}

	n := strings.Replace(filepath.Base(hocrfn), ".hocr", "", 1)
	return parseLineDetails(h, img, n)
}