package main

import (
	"bufio"
	"bytes"
	"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
	filename   string
	location   string
	token      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 {
		return nil, errors.New("json content-type is not implemented yet")
	} 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")
	}
	if _, ok := values["content"]; ok {
		entry := new(Entry)
		entry.content = values["content"][0]
		if name, ok := values["title"]; ok {
			entry.title = name[0]
		}
		if category, ok := values["category"]; ok {
			entry.tags = category
		} else if categories, ok := values["category[]"]; ok {
			entry.tags = categories
		} else {
			entry.tags = nil
		}
		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 token, ok := values["access_token"]; ok {
			entry.token = "Bearer " + token[0]
		}
		err := computeExtraSettings(entry)
		if err != nil {
			return nil, err
		}
		return entry, nil
	}
	return nil, errors.New("error parsing the entry")
}

func computeExtraSettings(entry *Entry) error {
	// 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 {
			_, _ = fmt.Fprintln(&filteredContent, text)
		}
	}
	entry.content = filteredContent.String()
	now := time.Now()
	// 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
	blogURL, err := GetBlogURL()
	if err != nil {
		return err
	}
	if len(entry.section) < 1 {
		entry.section = "micro"
	}
	entry.section = strings.ToLower(entry.section)
	if entry.section == "posts" {
		entry.filename = "content/" + entry.section + "/" + entry.slug + ".md"
		entry.location = blogURL + entry.section + "/" + entry.slug
	} else if entry.section == "thoughts" || entry.section == "links" || entry.section == "micro" {
		entry.filename = fmt.Sprintf("content/%v/%02d/%02d/%v.md", entry.section, now.Year(), int(now.Month()), entry.slug)
		entry.location = fmt.Sprintf("%v%v/%02d/%02d/%v", blogURL, entry.section, now.Year(), int(now.Month()), entry.slug)
	} else {
		entry.filename = "content/" + entry.section + "/" + entry.slug + ".md"
		entry.location = blogURL + 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) (string, error) {
	file := WriteHugoPost(entry)
	err := CreateFile(entry.filename, file, entry.title)
	if err != nil {
		return "", err
	}
	return entry.location, nil
}

func analyzeURL(url string) (filePath string, section string, slug string, err error) {
	blogUrl, err := GetBlogURL()
	if err != nil || !strings.HasPrefix(url, blogUrl) {
		return
	}
	path := strings.TrimSuffix(strings.TrimPrefix(url, blogUrl), "/")
	pathParts := strings.Split(path, "/")
	filePath = "content/" + path + ".md"
	section = pathParts[0]
	slug = pathParts[len(pathParts)-1]
	return
}

func ReadEntry(url string) (entry *Entry, err error) {
	filePath, section, slug, err := analyzeURL(url)
	if err != nil {
		return
	}
	fileContent, err := ReadFile(filePath)
	if err != nil {
		return
	}
	entry, err = ReadHugoPost(fileContent)
	if entry != nil {
		entry.location = url
		entry.filename = filePath
		entry.section = section
		entry.slug = slug
	}
	return
}