// Require iso-639-1 to convert language codes into human readable names
const ISO6391 = require('iso-639-1')

// Require lodash to help extract values from intermittent fields in the Tweet object
const _ = require('lodash') 

// Function to return a friendly language name (or "Unknown") for ISO language codes
function getLanguageName(isocode) {
  try { return ISO6391.getName(isocode) } 
	catch (err) { return 'Unknown' }
}

// Function to format numbers over 1000 from Stack Overflow https://stackoverflow.com/questions/9461621/format-a-number-as-2-5k-if-a-thousand-or-more-otherwise-900
function kFormatter(num) {
    return Math.abs(num) > 999 ? Math.sign(num)*((Math.abs(num)/1000).toFixed(1)) + 'k' : Math.sign(num)*Math.abs(num)
}

// Format the Tweet (including line breaks) as a quoted Slack message
const quotedMessage = steps.trigger.event.full_text
	.split('\n')
	.map(line => `> ${line}`)
	.join('\n')

// Construct URLs to reference in the formatted message
const tweetUrl = `https://twitter.com/${steps.trigger.event.user.screen_name}/statuses/${steps.trigger.event.id_str}`
const userUrl = `https://twitter.com/${steps.trigger.event.user.screen_name}/`

/* 
Use lodash to get the URL for an image representing the media since 
this object is not always present; `trigger.event.entities` will be present
when media — photos, animated GIFs or videos — are attached to the Tweet. 
This object should always containt a photo, "even in cases of a video 
and GIF being attached to Tweet."
https://developer.twitter.com/en/docs/twitter-api/v1/data-dictionary/object-model/entities
*/
const mediaUrl = _.get(steps, 'trigger.event.entities.media[0].media_url_https')
const mediaType = _.get(steps, 'trigger.event.entities.media[0].type')

// Format the message as Slack blocks - https://api.slack.com/block-kit
const blocks = []
blocks.push({
	"type": "section",
	"text": {
		"type": "mrkdwn",
		"text": `*<${tweetUrl}|New Mention> by <${userUrl}|${steps.trigger.event.user.screen_name}> (${steps.trigger.event.created_at}):*\n${quotedMessage}`
	},
		"accessory": {
			"type": "image",
			"image_url": steps.trigger.event.user.profile_image_url_https,
			"alt_text": "Profile picture"
		}
})

console.log(mediaType)

// If the Tweet contains a photo add it to the message
if(mediaUrl && mediaType === 'photo') {
	blocks.push({
		"type": "image",
		"image_url": mediaUrl,
		"alt_text": "Tweet Image"
	})
}

// Populate the context elements, button and footer
blocks.push({
	"type": "context",
	"elements": [
		{
			"type": "mrkdwn",
			"text": `*User:* ${steps.trigger.event.user.screen_name}`
		},
		{
			"type": "mrkdwn",
			"text": `*Followers:* ${kFormatter(steps.trigger.event.user.followers_count)}`
		},
		{
			"type": "mrkdwn",
			"text": `*Location:* ${steps.trigger.event.user.location}`
		},
		{
			"type": "mrkdwn",
			"text": `*Language:* ${getLanguageName(steps.trigger.event.lang)} (${steps.trigger.event.lang})`
		},
		{
			"type": "mrkdwn",
			"text": `*Description:* ${steps.trigger.event.user.description}`
		}
	]
},
{
	"type": "actions",
	"elements": [
		{
			"type": "button",
			"text": {
				"type": "plain_text",
				"text": "View on Twitter",
				"emoji": true
			},
			"url": tweetUrl
		}
	]
},
{
	"type": "context",
	"elements": [
		{
			"type": "mrkdwn",
			"text": `Sent via <https://pipedream.com/@/${steps.trigger.context.workflow_id}|Pipedream>`
		}
	]
},
{
	"type": "divider"
})

return blocks