package tools

import (
	"github.com/xuri/excelize/v2"
	_ "image/gif"
	_ "image/jpeg"
	_ "image/png"
	"io"
	"io/ioutil"
	"net/http"
	"net/url"
	"path/filepath"
	"penahub.gitlab.yandexcloud.net/backend/quiz/common.git/model"
	"regexp"
	"sort"
	"strconv"
	"strings"
)

const (
	bucketImages  = "squizimages"
	bucketFonts   = "squizfonts"
	bucketScripts = "squizscript"
	bucketStyle   = "squizstyle"
	bucketAnswers = "squizanswer"
)

func WriteDataToExcel(buffer io.Writer, questions []model.Question, answers []model.Answer) error {
	file := excelize.NewFile()
	sheet := "Sheet1"

	_, err := file.NewSheet(sheet)
	if err != nil {
		return err
	}

	sort.Slice(questions, func(i, j int) bool {
		return questions[i].Page > questions[j].Page
	})

	headers := []string{"Данные респондента"}
	mapQueRes := make(map[uint64]string)

	for _, q := range questions {
		if !q.Deleted {
			if q.Type == model.TypeResult {
				mapQueRes[q.Id] = q.Title + "\n" + q.Description
			} else {
				headers = append(headers, q.Title)
			}
		}
	}

	headers = append(headers, "Результат")

	// добавляем заголовки в первую строку
	for col, header := range headers {
		cell := ToAlphaString(col+1) + "1"
		if err := file.SetCellValue(sheet, cell, header); err != nil {
			return err
		}
	}

	// мапа для хранения обычных ответов респондентов
	standart := make(map[string][]model.Answer)

	// мапа для хранения данных респондентов
	results := make(map[string]model.Answer)

	// заполняем мапу ответами и данными респондентов
	for _, answer := range answers {
		if answer.Result {
			results[answer.Session] = answer
		} else {
			standart[answer.Session] = append(standart[answer.Session], answer)
		}
	}

	// записываем данные в файл
	row := 2
	for session, _ := range results {
		response := standart[session]
		if err := file.SetCellValue(sheet, "A"+strconv.Itoa(row), results[session].Content); err != nil {
			return err
		}
		count := 2
		for _, q := range questions {
			if !q.Deleted && q.Type != model.TypeResult {
				sort.Slice(response, func(i, j int) bool {
					return response[i].QuestionId < response[j].QuestionId
				})
				index := binarySearch(response, q.Id)
				if index != -1 {
					cell := ToAlphaString(count) + strconv.Itoa(row)
					typeMap := FileSearch(response[index].Content)
					noAccept := make(map[string]struct{})
					todoMap := make(map[string]string)
					for _, tipe := range typeMap {
						if tipe != "Text" && q.Type == model.TypeImages || q.Type == model.TypeVarImages {
							urle := ExtractImageURL(response[index].Content)
							urlData := strings.Split(urle, " ")
							for _, k := range urlData {
								u, err := url.Parse(k)
								if err == nil && u.Scheme != "" && u.Host != "" {
									picture, err := downloadImage(k)
									if err != nil {
										return err
									}
									file.SetColWidth(sheet, ToAlphaString(count), ToAlphaString(count), 50)
									file.SetRowHeight(sheet, row, 150)
									if err := file.AddPictureFromBytes(sheet, cell, picture); err != nil {
										return err
									}
									noAccept[response[index].Content] = struct{}{}
								}
							}
						} else if tipe != "Text" && q.Type == model.TypeFile {
							urle := ExtractImageURL(response[index].Content)
							display, tooltip := urle, urle
							if err := file.SetCellValue(sheet, cell, response[index].Content); err != nil {
								return err
							}
							if err := file.SetCellHyperLink(sheet, cell, urle, "External", excelize.HyperlinkOpts{
								Display: &display,
								Tooltip: &tooltip,
							}); err != nil {
								return err
							}
							noAccept[response[index].Content] = struct{}{}
						} else {
							todoMap[response[index].Content] = cell
						}
					}
					for cnt, cel := range todoMap {
						if _, ok := noAccept[cnt]; !ok {
							if err := file.SetCellValue(sheet, cel, cnt); err != nil {
								return err
							}
						}
					}

				} else {
					cell := ToAlphaString(count) + strconv.Itoa(row)
					if err := file.SetCellValue(sheet, cell, "-"); err != nil {
						return err
					}
				}
				count++
			}
		}
		cell := ToAlphaString(len(headers)) + strconv.Itoa(row)
		if err := file.SetCellValue(sheet, cell, mapQueRes[results[session].QuestionId]); err != nil {
			return err
		}
		row++
	}

	// cохраняем данные в буфер
	if err := file.Write(buffer); err != nil {
		return err
	}

	return nil
}

func binarySearch(answers []model.Answer, questionID uint64) int {
	left := 0
	right := len(answers) - 1
	for left <= right {
		mid := left + (right-left)/2
		if answers[mid].QuestionId == questionID {
			return mid
		} else if answers[mid].QuestionId < questionID {
			left = mid + 1
		} else {
			right = mid - 1
		}
	}
	return -1
}

func FileSearch(content string) map[string]string {
	types := make(map[string]string)

	words := strings.Fields(content)
	for _, word := range words {
		if strings.Contains(word, bucketImages) {
			types[word] = FileType(word)
		} else if strings.Contains(word, bucketFonts) {
			types[word] = FileType(word)
		} else if strings.Contains(word, bucketScripts) {
			types[word] = FileType(word)
		} else if strings.Contains(word, bucketStyle) {
			types[word] = FileType(word)
		} else if strings.Contains(word, bucketAnswers) {
			types[word] = FileType(word)
		} else {
			types[word] = "Text"
		}
	}

	return types
}

func FileType(filename string) string {
	parts := strings.Split(filename, ".")
	extension := parts[len(parts)-1]

	switch extension {
	case "png", "jpg", "jpeg", "gif", "bmp", "svg", "webp", "tiff", "ico":
		return "Image"
	default:
		return "File"
	}
}

func downloadImage(url string) (*excelize.Picture, error) {
	resp, err := http.Get(url)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()

	imgData, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		return nil, err
	}

	ext := filepath.Ext(url)
	if ext == "" {
		contentType := resp.Header.Get("Content-Type")
		switch {
		case strings.HasPrefix(contentType, "image/jpeg"):
			ext = ".jpg"
		case strings.HasPrefix(contentType, "image/png"):
			ext = ".png"
		default:
			ext = ".png"
		}
	}

	pic := &excelize.Picture{
		Extension: ext,
		File:      imgData,
		Format: &excelize.GraphicOptions{
			AutoFit:     true,
			Positioning: "oneCell",
		},
	}
	return pic, nil
}

func ToAlphaString(col int) string {
	var result string
	for col > 0 {
		col--
		result = string(rune('A'+col%26)) + result
		col /= 26
	}
	return result
}

func ExtractImageURL(htmlContent string) string {
	re := regexp.MustCompile(`(?:<img[^>]*src="([^"]+)"[^>]*>)|(?:<td[^>]*>.*?<img[^>]*src="([^"]+)"[^>]*>.*?</td>)|(?:<tr[^>]*>.*?<td[^>]*>.*?<img[^>]*src="([^"]+)"[^>]*>.*?</td>.*?</tr>)|(?:<a[^>]*\s+download[^>]*>([^<]+)<\/a>)`)
	matches := re.FindAllStringSubmatch(htmlContent, -1)

	for _, match := range matches {
		for i := 1; i < len(match); i++ {
			if match[i] != "" {
				return strings.TrimSpace(match[i])
			}
		}
	}
	return htmlContent
}