package main

import (
	"encoding/json"
	"errors"
	"io/ioutil"
	"net/http"
)

type ItemList struct {
	Items []*Item `json:"items"`
}

type Item struct {
	Type       []string    `json:"type"`
	Properties *Properties `json:"properties"`
}

type Properties struct {
	Name      []string `json:"name"`
	Published []string `json:"published"`
	Updated   []string `json:"updated"`
	Category  []string `json:"category"`
	Content   []string `json:"content"`
	Url       []string `json:"url"`
}

func QueryURL(url string, limit int) ([]byte, error) {
	if len(url) == 0 {
		url = BlogUrl
	}
	if url == BlogUrl {
		allPosts, err := allPosts(url)
		if err != nil {
			return nil, err
		}
		itemList := &ItemList{}
		for i, postURL := range allPosts {
			if limit != 0 && i == limit {
				break
			}
			item, _ := getItem(postURL)
			itemList.Items = append(itemList.Items, item)
		}
		jsonBytes, err := json.Marshal(itemList)
		if err != nil {
			err = errors.New("failed to marshal json")
			return nil, err
		}
		return jsonBytes, err
	} else {
		item, err := getItem(url)
		if err != nil {
			return nil, err
		}
		jsonBytes, err := json.Marshal(item)
		if err != nil {
			err = errors.New("failed to marshal json")
			return nil, err
		}
		return jsonBytes, err
	}
}

func getItem(url string) (item *Item, err error) {
	entry, err := ReadEntry(url)
	if err != nil {
		return
	}
	item = &Item{
		Type: []string{"h-entry"},
		Properties: &Properties{
			Name:      []string{entry.title},
			Published: []string{entry.date},
			Updated:   []string{entry.lastmod},
			Category:  entry.tags,
			Content:   []string{entry.content},
			Url:       []string{entry.location},
		},
	}
	return
}

func allPosts(url string) ([]string, error) {
	jsonFeed := &struct {
		Items []struct {
			Url string `json:"url"`
		} `json:"items"`
	}{}
	resp, err := http.Get(url + "feed.json")
	if err != nil {
		return nil, errors.New("failed to get json feed")
	}
	defer resp.Body.Close()
	body, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		return nil, errors.New("failed to read json feed")
	}
	err = json.Unmarshal(body, &jsonFeed)
	if err != nil {
		return nil, errors.New("failed to parse json feed")
	}
	var allUrls []string
	for _, item := range jsonFeed.Items {
		allUrls = append(allUrls, item.Url)
	}
	return allUrls, nil
}