const { spawn, exec } = require('child_process')
const fs = require('fs')
const youtubedl = require('youtube-dl-exec')
const tmp = require('tmp')
const playlist = require('./playlist-search')

const STREAM_URL = "https://www.youtube.com/henrikomagnifico/live"
const DURATION_REGEX = /(\d{1,2}:\d{2})\/(\d{1,2}:\d{2})/
const EXPIRATION_REGEX = /.+\/expire\/([0-9]{10})\/.+/

let currentTrack = {}
let nextTrackTimestamp = 0

let resolvedUrl = {
	url: '',
	expires: 0
}


function readText(tmpfile, charWhitelist) {
	return new Promise((resolve, reject) => {
	    let command = `tesseract ${tmpfile.name} -`
		if (charWhitelist) {
			command += ` -c tessedit_char_whitelist="${charWhitelist}"`
		}
		exec(command, ((error, stdout, stderr) => {
			tmpfile.removeCallback()
			if (error) {
				console.error(stderr)
				reject(error)
			} else {
				resolve(stdout)
			}
		}))
	})
}

function thresholdImage(image, threshold) {
    return new Promise(((resolve, reject) => {
    	const tmpFile = tmp.fileSync()
        exec(`convert png:${image.name} -white-threshold ${threshold}% -colorspace HSB -channel B -separate ${tmpFile.name}`, ((error, stdout, stderr) => {
        	if (error) {
        		console.error(stderr)
				tmpFile.removeCallback()
				reject(error)
			} else {
        		resolve(tmpFile)
			}
		}))
	}))

}

function getRegion(frame, x, y, width, height) { // Returns Promise<Buffer>
	return new Promise(function (resolve, reject) {
		const tmpFile = tmp.fileSync()
		exec(`convert png:${frame.name} -negate -crop ${width}x${height}+${x}+${y} png:${tmpFile.name}`, ((error, stdout, stderr) => {
			if (error) {
				console.error(stderr)
				tmpFile.removeCallback()
				reject(error)
			} else {
				resolve(tmpFile)
			}
		}))
	});
}

function getFrame(url) {
	return new Promise((resolve, reject) => {
	    const frameFile = tmp.fileSync()
		exec(`ffmpeg -i ${url} -y -f image2 -c:v png -frames:v 1 ${frameFile.name}`, (err, stdout, stderr) => {
			if (err) {
				console.log(stderr)
				frameFile.removeCallback()
				reject(err)
			} else {
				resolve(frameFile)
			}
		})
	});
}

function getYoutubeStream() {
	return new Promise((resolve, reject) => {
		youtubedl(STREAM_URL, {
			dumpJson: true,
			format: "best"
		}).then(output => resolve(output.url))
			.catch(err => reject(err))
	})
}

function getYoutubeAudioUrl() {

}

function getVotes(ocrResults) {
	return ocrResults.map((text, index, arr) => { // Actually perform the search. Map returns array of search results, result.refIndex is of interest
		const title = text[0].trim()
		const album = text[1].trim()
		const position_duration = text[2].trim()
		let capturedDuration = DURATION_REGEX.test(position_duration) ? position_duration.match(DURATION_REGEX) : ['', '', '']
		const retval = {
			result: playlist.search(album, title, capturedDuration[2]),
			position: capturedDuration[1]
		}

		return retval
	})
}

function tallyVotes(votes) {
	const trackResults = {}
	const positionResults = {}
	votes.forEach(vote => {
		if (vote.result != null) {
			if (trackResults.hasOwnProperty(vote.result.refIndex)) {
				trackResults[`${vote.result.refIndex}`] = trackResults[`${vote.result.refIndex}`] + 1
			} else {
				trackResults[`${vote.result.refIndex}`] = 1
			}
		}
		if (vote.position) {
			if (positionResults.hasOwnProperty(vote.position)) {
				positionResults[`${vote.position}`] = positionResults[`${vote.position}`] + 1
			} else {
				positionResults[`${vote.position}`] = 1
			}
		}
	})
	if (trackResults.length === 0) {
		console.log("votes resulted in no results!")
		return {
			position: null,
			positionConfidence: 0,
			result: null,
			resultConfidence: 0
		}
	}

	// Retrieve votes
	let trackIndex = Object.keys(trackResults)[0]
	let trackMaxVotes = trackResults[trackIndex]
	let position = Object.keys(positionResults)[0]
	let positionMaxVotes = positionResults[position]
	for (const index in trackResults) {
		if (trackResults[index] > trackMaxVotes) {
			trackIndex = index
			trackMaxVotes = trackResults[index]
		}
	}
	for (const positionKey in positionResults) {
		if (positionResults[positionKey] > positionMaxVotes) {
			position = positionKey
			positionMaxVotes = positionResults[positionKey]
		}
	}

	// console.log(JSON.stringify(votes))
	console.debug(`Vote was index ${trackIndex}`)
	const actualResult = votes.find(v => v.result != null && `${v.result.refIndex}` === trackIndex).result.item
	return {
		position: position,
		positionConfidence: positionMaxVotes / votes.length,
		result: actualResult,
		resultConfidence: trackMaxVotes / votes.length
	}
}

function timeUntilNextTrack(position, duration) {
	const timeRegex = /(\d{1,2}):(\d{2})/
	const durationValues = duration.match(timeRegex)
	const positionValues = position.match(timeRegex)
	const durationInSeconds = (parseInt(durationValues[1]) * 60) + parseInt(durationValues[2])
	const positionInSeconds = (parseInt(positionValues[1]) * 60) + parseInt(positionValues[2])
	return durationInSeconds - positionInSeconds
}

function performQuorumProcessing(titleCroppedPromise, albumCroppedPromise, durationCroppedPromise) {
	return new Promise(((resolve, reject) => {
		Promise.all([titleCroppedPromise, albumCroppedPromise, durationCroppedPromise]) // Wait for all promises to be resolved, returns paths to cropped segments of frame
			.then(images => {
				const thresholds = [15, 12.5, 10, 7.5, 5]
				Promise.all(thresholds.map(t => { // Threshold all segments at determined levels, returns text determined by each threshold level as [title, album, position/duration]
					return Promise.all([
						thresholdImage(images[0], t).then(file => readText(file)),
						thresholdImage(images[1], t).then(file => readText(file)),
						thresholdImage(images[2], t).then(file => readText(file, "1234567890:/"))
					])
				})).then(allOcrResults => { // Perform search based on resolved text. Perform voting here between thresholds
				    // console.debug(allOcrResults)
					// Cast votes
					const votes = getVotes(allOcrResults) // Actually perform the search. Map returns array of search results, result.refIndex is of interest
					// console.debug(JSON.stringify(votes))

					// Tally votes
					const winner = tallyVotes(votes)

					console.debug(`Position confidence: ${winner.positionConfidence}`)
					console.debug(`Result confidence: ${winner.resultConfidence}`)

					resolve(winner)
				})
			}).catch(error => reject(error))
	}))
}

async function updateStreamUrl() {
	const ytStreamUrl = await getYoutubeStream()
	resolvedUrl.url = ytStreamUrl
	resolvedUrl.expires = parseInt(ytStreamUrl.match(EXPIRATION_REGEX)[1]) * 1000
}

async function updateTrackInfo() {
	const urlExpiresSoon = resolvedUrl.expires < (Date.now() + (30 * 60 * 1000))
	if (resolvedUrl.expires < Date.now()) {
		await updateStreamUrl()
        console.log("Got stream info")
	} else if (urlExpiresSoon) {
		updateStreamUrl().then(() => console.log("Updated stream info in the background"))
	}
	console.log(`Now: ${Date.now()}\tExpiration: ${resolvedUrl.expires}`)
	const frame = await getFrame(resolvedUrl.url)
    const frameTime = Date.now()

	const titlePromise = getRegion(frame, 432, 906, 1487, 54)
	const albumPromise = getRegion(frame, 440, 957, 1487, 32)
	const durationPromise = getRegion(frame, 0, 1028, 235, 34)

	const result = await performQuorumProcessing(titlePromise, albumPromise, durationPromise)
	if (result.resultConfidence < 0.5) {
		setTimeout(() => updateTrackInfo(), 250)
		return;
	}
	currentTrack = result.result
	console.log(`${currentTrack.album}: ${currentTrack.track} (${result.position}/${currentTrack.duration})`)
	const secondsUntilNext = timeUntilNextTrack(result.position, currentTrack.duration)
	const processingTime = Date.now() - frameTime
	nextTrackTimestamp = frameTime + (secondsUntilNext * 1000)
	setTimeout(() => updateTrackInfo(), (secondsUntilNext * 1000) - processingTime + 500)
	console.log(`Frame processing took ${processingTime}ms`)
	console.log(`Next track should be at: ${new Date(nextTrackTimestamp).toLocaleString()}`)
}

// getYoutubeStream()
// 	.then(url => getFrame(url))
// 	.then(frame => {
// 		const titlePromise = getRegion(frame, 432, 906, 1487, 54)
// 		const albumPromise = getRegion(frame, 440, 957, 1487, 32)
// 		const durationPromise = getRegion(frame, 0, 1028, 235, 34)
//
// 		return performQuorumProcessing(titlePromise, albumPromise, durationPromise)
// 	})
// 	.then(value => {
// 		console.log('Processing complete, voted result was:')
// 		console.log(`${value.result.album}: ${value.result.track} (${value.position}/${value.result.duration})`)
// 		console.log(`Time until next track: ${timeUntilNextTrack(value.position, value.result.duration)}`)
// 	})
// 	.catch(err => console.error(err))

updateTrackInfo()