package main

import (
	"bufio"
	"bytes"
	"encoding/json"
	"errors"
	"fmt"
	"io/ioutil"
	"math/rand"
	"net/http"
	"net/url"
	"strings"
	"time"
)

type Entry struct {
	content        string
	title          string
	date           string
	lastmod        string
	section        string
	tags           []string
	link           string
	slug           string
	replyLink      string
	replyTitle     string
	likeLink       string
	likeTitle      string
	syndicate      []string
	language       string
	translationKey string
	images         []Image
	audio          string
	filename       string
	location       string
	token          string
}

type Image struct {
	url string
	alt string
}

func CreateEntry(contentType ContentType, r *http.Request) (*Entry, error) {
	if contentType == WwwForm {
		bodyString, err := parseRequestBody(r)
		if err != nil {
			return nil, err
		}
		bodyValues, err := url.ParseQuery(bodyString)
		if err != nil {
			return nil, errors.New("failed to parse query")
		}
		return createEntryFromValueMap(bodyValues)
	} else if contentType == Multipart {
		err := r.ParseMultipartForm(1024 * 1024 * 16)
		if err != nil {
			return nil, errors.New("failed to parse Multipart")
		}
		return createEntryFromValueMap(r.MultipartForm.Value)
	} else if contentType == Json {
		bodyString, err := parseRequestBody(r)
		if err != nil {
			return nil, err
		}
		parsedMfItem := &MicroformatItem{}
		err = json.Unmarshal([]byte(bodyString), &parsedMfItem)
		if err != nil {
			return nil, errors.New("failed to parse Json")
		}
		return createEntryFromMicroformat(parsedMfItem)
	} else {
		return nil, errors.New("unsupported content-type")
	}
}

func parseRequestBody(r *http.Request) (string, error) {
	defer r.Body.Close()
	bodyBytes, err := ioutil.ReadAll(r.Body)
	if err != nil {
		return "", errors.New("failed to read body")
	}
	return string(bodyBytes), nil
}

func createEntryFromValueMap(values map[string][]string) (*Entry, error) {
	if h, ok := values["h"]; ok && (len(h) != 1 || h[0] != "entry") {
		return nil, errors.New("only entry type is supported so far")
	}
	entry := &Entry{}
	if content, ok := values["content"]; ok {
		entry.content = content[0]
	}
	if name, ok := values["name"]; ok {
		entry.title = name[0]
	}
	if category, ok := values["category"]; ok {
		entry.tags = category
	} else if categories, ok := values["category[]"]; ok {
		entry.tags = categories
	}
	if slug, ok := values["mp-slug"]; ok && len(slug) > 0 && slug[0] != "" {
		entry.slug = slug[0]
	}
	if inReplyTo, ok := values["in-reply-to"]; ok {
		entry.replyLink = inReplyTo[0]
	}
	if likeOf, ok := values["like-of"]; ok {
		entry.likeLink = likeOf[0]
	}
	if bookmarkOf, ok := values["bookmark-of"]; ok {
		entry.link = bookmarkOf[0]
	}
	if syndicate, ok := values["mp-syndicate-to"]; ok {
		entry.syndicate = syndicate
	} else if syndicates, ok := values["mp-syndicate-to[]"]; ok {
		entry.syndicate = syndicates
	}
	if photo, ok := values["photo"]; ok {
		entry.images = append(entry.images, Image{url: photo[0]})
	} else if photos, ok := values["photo[]"]; ok {
		for _, photo := range photos {
			entry.images = append(entry.images, Image{url: photo})
		}
	}
	if photoAlt, ok := values["mp-photo-alt"]; ok {
		if len(entry.images) > 0 {
			entry.images[0].alt = photoAlt[0]
		}
	} else if photoAlts, ok := values["mp-photo-alt[]"]; ok {
		for i, photoAlt := range photoAlts {
			if len(entry.images) > i {
				entry.images[i].alt = photoAlt
			}
		}
	}
	if audio, ok := values["audio"]; ok {
		entry.audio = audio[0]
	} else if audio, ok := values["audio[]"]; ok {
		entry.audio = audio[0]
	}
	if token, ok := values["access_token"]; ok {
		entry.token = "Bearer " + token[0]
	}
	err := computeExtraSettings(entry)
	if err != nil {
		return nil, err
	}
	return entry, nil
}

func createEntryFromMicroformat(mfEntry *MicroformatItem) (*Entry, error) {
	if len(mfEntry.Type) != 1 || mfEntry.Type[0] != "h-entry" {
		return nil, errors.New("only entry type is supported so far")
	}
	entry := &Entry{}
	if mfEntry.Properties != nil && len(mfEntry.Properties.Content) == 1 && len(mfEntry.Properties.Content[0]) > 0 {
		entry.content = mfEntry.Properties.Content[0]
	}
	if len(mfEntry.Properties.Name) == 1 {
		entry.title = mfEntry.Properties.Name[0]
	}
	if len(mfEntry.Properties.Category) > 0 {
		entry.tags = mfEntry.Properties.Category
	}
	if len(mfEntry.Properties.MpSlug) == 1 && len(mfEntry.Properties.MpSlug[0]) > 0 {
		entry.slug = mfEntry.Properties.MpSlug[0]
	}
	if len(mfEntry.Properties.InReplyTo) == 1 {
		entry.replyLink = mfEntry.Properties.InReplyTo[0]
	}
	if len(mfEntry.Properties.LikeOf) == 1 {
		entry.likeLink = mfEntry.Properties.LikeOf[0]
	}
	if len(mfEntry.Properties.BookmarkOf) == 1 {
		entry.link = mfEntry.Properties.BookmarkOf[0]
	}
	if len(mfEntry.Properties.MpSyndicateTo) > 0 {
		entry.syndicate = mfEntry.Properties.MpSyndicateTo
	}
	if len(mfEntry.Properties.Photo) > 0 {
		for _, photo := range mfEntry.Properties.Photo {
			if theString, justString := photo.(string); justString {
				entry.images = append(entry.images, Image{url: theString})
			} else if thePhoto, isPhoto := photo.(map[string]interface{}); isPhoto {
				image := Image{}
				// Micropub spec says "value" is correct, but not sure about that
				if photoUrl, ok := thePhoto["value"].(string); ok {
					image.url = photoUrl
				}
				if alt, ok := thePhoto["alt"].(string); ok {
					image.alt = alt
				}
				entry.images = append(entry.images, image)
			}
		}
	}
	if len(mfEntry.Properties.Audio) > 0 {
		entry.audio = mfEntry.Properties.Audio[0]
	}
	err := computeExtraSettings(entry)
	if err != nil {
		return nil, err
	}
	return entry, nil
}

func computeExtraSettings(entry *Entry) error {
	now := time.Now()
	// Set date
	entry.date = now.Format(time.RFC3339)
	// Find settings hidden in content
	var filteredContent bytes.Buffer
	contentScanner := bufio.NewScanner(strings.NewReader(entry.content))
	for contentScanner.Scan() {
		text := contentScanner.Text()
		if strings.HasPrefix(text, "section: ") {
			// Section
			entry.section = strings.TrimPrefix(text, "section: ")
		} else if strings.HasPrefix(text, "title: ") {
			// Title
			entry.title = strings.TrimPrefix(text, "title: ")
		} else if strings.HasPrefix(text, "slug: ") {
			// Slug
			entry.slug = strings.TrimPrefix(text, "slug: ")
		} else if strings.HasPrefix(text, "tags: ") {
			// Tags
			entry.tags = strings.Split(strings.TrimPrefix(text, "tags: "), ",")
		} else if strings.HasPrefix(text, "link: ") {
			// Link
			entry.link = strings.TrimPrefix(text, "link: ")
		} else if strings.HasPrefix(text, "reply-link: ") {
			// Reply link
			entry.replyLink = strings.TrimPrefix(text, "reply-link: ")
		} else if strings.HasPrefix(text, "reply-title: ") {
			// Reply title
			entry.replyTitle = strings.TrimPrefix(text, "reply-title: ")
		} else if strings.HasPrefix(text, "like-link: ") {
			// Like link
			entry.likeLink = strings.TrimPrefix(text, "like-link: ")
		} else if strings.HasPrefix(text, "like-title: ") {
			// Like title
			entry.likeTitle = strings.TrimPrefix(text, "like-title: ")
		} else if strings.HasPrefix(text, "language: ") {
			// Language
			entry.language = strings.TrimPrefix(text, "language: ")
		} else if strings.HasPrefix(text, "translationkey: ") {
			// Translation key
			entry.translationKey = strings.TrimPrefix(text, "translationkey: ")
		} else if strings.HasPrefix(text, "images: ") {
			// Images
			for _, image := range strings.Split(strings.TrimPrefix(text, "images: "), ",") {
				entry.images = append(entry.images, Image{url: image})
			}
		} else if strings.HasPrefix(text, "audio: ") {
			// Audio
			entry.audio = strings.TrimPrefix(text, "audio: ")
		} else {
			_, _ = fmt.Fprintln(&filteredContent, text)
		}
	}
	entry.content = filteredContent.String()
	// Check if content contains images or add them
	for _, image := range entry.images {
		if !strings.Contains(entry.content, image.url) {
			if len(image.alt) > 0 {
				entry.content += "\n![" + image.alt + "](" + image.url + " \"" + image.alt + "\")\n"
			} else {
				entry.content += "\n![](" + image.url + ")\n"
			}
		}
	}
	// Compute slug if empty
	if len(entry.slug) == 0 || entry.slug == "" {
		random := generateRandomString(now, 5)
		entry.slug = fmt.Sprintf("%v-%02d-%02d-%v", now.Year(), int(now.Month()), now.Day(), random)
	}
	// Compute filename and location
	contentFolder := "content"
	localizedBlogUrl := BlogUrl
	if len(entry.language) > 0 && entry.language != "en" {
		// Append language to content folder: "content-de" for language "de"
		contentFolder += "-" + entry.language
		// Append language to BlogUrl
		localizedBlogUrl += entry.language + "/"
	}
	if len(entry.section) < 1 {
		entry.section = "micro"
	}
	entry.section = strings.ToLower(entry.section)
	if entry.section == "thoughts" || entry.section == "links" || entry.section == "micro" {
		entry.filename = fmt.Sprintf("%v/%v/%02d/%02d/%v.md", contentFolder, entry.section, now.Year(), int(now.Month()), entry.slug)
		entry.location = fmt.Sprintf("%v%v/%02d/%02d/%v/", localizedBlogUrl, entry.section, now.Year(), int(now.Month()), entry.slug)
	} else {
		entry.filename = fmt.Sprintf("%v/%v/%v.md", contentFolder, entry.section, entry.slug)
		entry.location = fmt.Sprintf("%v%v/%v/", localizedBlogUrl, entry.section, entry.slug)
	}
	return nil
}

func generateRandomString(now time.Time, n int) string {
	rand.Seed(now.UnixNano())
	letters := []rune("abcdefghijklmnopqrstuvwxyz")
	b := make([]rune, n)
	for i := range b {
		b[i] = letters[rand.Intn(len(letters))]
	}
	return string(b)
}

func WriteEntry(entry *Entry) (location string, err error) {
	file, err := WriteHugoPost(entry)
	if err != nil {
		return
	}
	err = SelectedStorage.CreateFile(entry.filename, file, entry.title)
	if err != nil {
		return
	}
	location = entry.location
	return
}

func analyzeURL(url string) (filePath string, section string, slug string, lang string, err error) {
	if !strings.HasPrefix(url, BlogUrl) {
		return
	}
	contentFolder := "content"
	path := ""
	if strings.HasPrefix(url, BlogUrl+"de/") {
		lang = "de"
		// German content folder
		contentFolder += "-" + lang
		path = strings.TrimSuffix(strings.TrimPrefix(url, BlogUrl+lang+"/"), "/")
	} else {
		path = strings.TrimSuffix(strings.TrimPrefix(url, BlogUrl), "/")
	}
	pathParts := strings.Split(path, "/")
	filePath = contentFolder + "/" + path + ".md"
	section = pathParts[0]
	slug = pathParts[len(pathParts)-1]
	return
}

func ReadEntry(url string) (entry *Entry, err error) {
	filePath, section, slug, lang, err := analyzeURL(url)
	if err != nil {
		return
	}
	fileContent, exists, err := SelectedStorage.ReadFile(filePath)
	if err != nil || !exists {
		err = errors.New("failed to read file or entry doesn't exist")
		return
	}
	entry, err = ReadHugoPost(fileContent)
	if entry != nil {
		entry.location = url
		entry.filename = filePath
		entry.section = section
		entry.slug = slug
		entry.language = lang
	}
	return
}