#!/bin/bash

###
# Consumes a given image to convert it to ICO
# @param Path to the input file
###
function convertToIco {
	imageWidth=$(identify -ping -format '%w ' "${1}" | awk -F' ' '{ print $NF }')
	imageHeight=$(identify -ping -format '%h ' "${1}" | awk -F' ' '{ print $NF }')

	if [ ${imageWidth} -lt 64 ] || [ ${imageHeight} -lt 64 ]; then
		echo "Warning: Favicon is only ${imageWidth}x${imageHeight}, it'll probably look pixely"
	fi

	mimeType=$(file -bi "${1}")
	if [ $? -eq 0 ] && ! grep -qE "^image/vnd.microsoft.icon" <<< "${mimeType}"; then
		if convert "${1}" -resize "64x64" "$(dirname "${1}")/$(basename "${1}" ".${1##*.}").ico"; then
			rm "${1}"
		else
			return 1
		fi
	fi
}

###
# Tries to download the favicon of a website
# @param URL of the website
# @param Filename of the downloaded ico file
###
function fetchFavicon {
	domain=$(awk -F'/' '{ print $3 }' <<< "${1}")
	protoAndDomain=$(awk -F'/' '{ print $1"//"$3 }' <<< "${1}")

	echo "Fetching favicon for ${protoAndDomain}"

	faviconUrl=$(curl -s -L "${1}" | grep -E '<link.*rel="icon"' | sed 's/.*href="\([^"]*\)".*/\1/' 2>/dev/null)
	if [ $? -eq 0 ] && [ "${faviconUrl}" != "" ]; then
		if ! grep -E "https?://" <<< "${faviconUrl}"; then
			faviconUrl="${protoAndDomain}${faviconUrl}"
		fi

		mimeType=$(curl -Lso "${2}" -w "%{content_type}" "${faviconUrl}")
		if [ $? -eq 0 ] && grep -E '^image/' <<< "${mimeType}"; then
			echo "Success using link tag method"
			convertToIco "${2}"
			return 0
		fi
	fi

	curlOut=($(curl -Lso "${2}" -w '%{http_code} %{content_type}' "${protoAndDomain}/favicon.ico"))
	if [ $? -eq 0 ] && [ "${curlOut[0]}" = "200" ] && grep -qE '^image/' <<< "${curlOut[1]}"; then
		echo "Success using /favicon.ico method"
		convertToIco "${2}"
		return 0
	fi

	curlOut=($(curl -Lso "${2}" -w '%{http_code} %{content_type}' "https://www.google.com/s2/favicons?domain=${domain}&sz=64"))
	if [ $? -eq 0 ] && [ "${curlOut[0]}" = "200" ] && grep -qE '^image/' <<< "${curlOut[1]}"; then
		echo "Success using Google Favicons API"
		convertToIco "${2}"
		return 0
	fi

	echo "Failed. You'll have to supply your own icon file at:"
	echo "  ${2}"
}