/*
This contains our functions used for image searches
*/

package main

import (
	"io/ioutil"
	"net/http"
	"time"
	"math/rand"
	"fmt"
	"strconv"
	"os"

	"github.com/buger/jsonparser"
)

// get the length of array for our parser
func getArrayLen(value []byte) (int, error) {
	ret := 0
	arrayCallback := func(value []byte, dataType jsonparser.ValueType, offset int, err error) {
		ret++
	}

	if _, err := jsonparser.ArrayEach(value, arrayCallback); err != nil {
		return 0, fmt.Errorf("getArrayLen ArrayEach error: %v", err)
	}
	return ret, nil
}

//  get the length of object for our parser
func getObjectLen(value []byte) (int, error) {
	ret := 0
	objectCallback := func(key []byte, value []byte, dataType jsonparser.ValueType, offset int) error {
		ret++
		return nil
	}

	if err := jsonparser.ObjectEach(value, objectCallback); err != nil {
		return 0, fmt.Errorf("getObjectLen ObjectEach error: %v", err)
	}

	return ret, nil
}

// search based on the most appropriate location
func get_image(sub string) <-chan string {
	// make the channell
	ret := make(chan string)

	go func() {
		defer close(ret)

		// setup variable
		var image string
		var cache_exists bool = false

		// check if a cached version exists
		file, err := os.Stat(cache_location + sub)
		
		// if it exists, check it's timestamp
		if !os.IsNotExist(err) {
			// get the current time
			currenttime := time.Now()

			// get the file's last modified time
			modifiedtime := file.ModTime()

			// get the difference in time
			difftime := currenttime.Sub(modifiedtime)

			// check if it meets our cutoff time
			if difftime > cache_time {
				// too old, delete the old file
				os.Remove(cache_location + sub)
			} else {
				// else it's new enough, let it be used later
				cache_exists = true
			}
		}

		// check reddit
		image = <-get_subreddit_image(sub, cache_exists)
		ret <- image
		return


		// nothing found
		ret <- ""

	}()

	return ret
}

// imgur request
func get_imgur_image(sub string) <-chan string {
	// make channel
	ret := make(chan string)

	go func() {
		defer close(ret)

		// create the proper url with the subreddit
		url := "https://api.imgur.com/3/gallery/r/" + sub + "/time/1"

		// set 5 second timeout on request
		client := http.Client {
			Timeout: 5 * time.Second,
		}

		// create the request
		req, err := http.NewRequest("GET", url, nil)
		req.Header.Add("Authorization", "Client-ID " + auth.imgur)

		// get the content of the page
		resp, err := client.Do(req)
		defer resp.Body.Close()

		// read response
		out, err := ioutil.ReadAll(resp.Body)
		if err != nil {
			fmt.Println("Error reading response from imgur, ", err)
			return
		}

		// get a random number for the image
		//outlen, _ := getArrayLen(out)
		//random_img := rand.Intn(outlen)

		// parse the data (fix this)
		img_url, _ := jsonparser.GetString(out, "[0]", "[0]", "link")
		fmt.Println(string(img_url))

		ret <- ""
	}()

	return ret
}

// subreddit request
func get_subreddit_image(sub string, cache bool) <-chan string {
	ret := make(chan string)

	go func() {
		defer close(ret)

		// information variable
		var out []byte

		// if a cached version exists, use that instead
		if cache == true {
			// read our cached file
			outdata, err := ioutil.ReadFile(cache_location + sub)
			if err != nil {
				fmt.Println("Error reading from cached reddit file, ", err)
				return
			}

			// copy to our info var
			out = outdata
			
		} else { // else pull it from the web
			// create the proper url with the subreddit
			url := "https://www.reddit.com/r/" + sub + "/.json?show=all&limit=100"

			// set 5 second timeout on request
			client := http.Client {
				Timeout: 5 * time.Second,
			}

			req, err := http.NewRequest("GET", url, nil)
			req.Header.Add("User-Agent", "BunnyBot")

			// get the content of the page
			resp, err := client.Do(req)
			defer resp.Body.Close()

			// read response
			outdata, err := ioutil.ReadAll(resp.Body)
			if err != nil {
				fmt.Println("Error reading response from reddit, ", err)
				return
			}

			// copy to our info var
			out = outdata

			// attempt to make a cache file, don't do anything if it doesn't get created (who cares?)
			os.Create(cache_location + sub)
			var file, _ = os.OpenFile(cache_location + sub, os.O_RDWR, 0777)
			defer file.Close()
			file.Write(outdata)
		}

		

		// make sure we aren't grabbing a text post by cylcing through looking for an image
		limit64, _ := jsonparser.GetInt(out, "data", "dist")
		limit := int(limit64) // convert from int64 to int

		// loop through and try to find a post that isn't a text post
		for i := 0; i < limit; i++ {
			// get a random number
			random_img := rand.Intn(limit)

			// check the post hint to see what type of post it is
			hint, _ := jsonparser.GetString(out, "data", "children", "[" + strconv.Itoa(random_img) + "]", "data", "post_hint")

			// get the domain to also check againist
			domain, _ := jsonparser.GetString(out, "data", "children", "[" + strconv.Itoa(random_img) + "]", "data", "domain")

			// make sure that it is an image, or at least a gif
			if hint == "image" || hint == "link" || hint == "rich:video" || domain == "i.redd.it" || domain == "i.imgur.com" {
				image, _ := jsonparser.GetString(out, "data", "children", "[" + strconv.Itoa(random_img) + "]", "data", "url")
				ret <- image
				return
			}
		}
	}()

	return ret
}