helpers.lua

----- Debug -----------
----- Debug -----------

local LrDate = import( 'LrDate' )


------------ helper functions for LR to WP Plugin --------------------------------------------

-- Returns the baseFilename, and Extension as 2 values
function SplitFilename(strFilename)
    if strFilename ~= nil then
        return string.match(strFilename, "(.-)%.(%a+)")
    else
        return nil
    end
end

---------------------- shorted if expressions ----------------------------------------------------------
function ifnil(str, subst)
	return ((str == nil) and subst) or str
end 

function iif(condition, thenExpr, elseExpr)
	if condition then
		return thenExpr
	else
		return elseExpr
	end
end 

-- iso8601ToTime(dateTimeISO8601) : returns Cocoa timestamp as used all through out Lr  
function iso8601ToTime(dateTimeISO8601)
    -- ISO8601: YYYY-MM-DD{THH:mm:{ss{Zssss}}
    -- date is mandatory, time as whole, seconds and timezone may or may not be present, e.g.:
        --	srcDateTimeISO8601 = '2016-07-06T17:16:15Z-3600'
        --	srcDateTimeISO8601 = '2016-07-06T17:16:15Z'
        --	srcDateTimeISO8601 = '2016-07-06T17:16:15'
        --	srcDateTimeISO8601 = '2016-07-06T17:16'
        --	srcDateTimeISO8601 = '2016-07-06'

	local year, month, day, hour, minute, second, tzone = string.match(dateTimeISO8601, '(%d%d%d%d)%-(%d%d)%-(%d%d)T*(%d*):*(%d*):*(%d*)Z*([%-%+]*%d*)')
	return LrDate.timeFromComponents(tonumber(ifnil(year, "2001")), tonumber(ifnil(month,"1")), tonumber(ifnil(day, "1")), 
									 tonumber(ifnil(hour, "0")), tonumber(ifnil(minute, "0")), tonumber(ifnil(second, "0")),
									 iif(ifnil(tzone, '') == '', "local", tzone))
end

-- write csv-file data to path with given seperator sep
function csvwrite(path, data, sep)
	  sep = sep or ';'
	  local file = assert(io.open(path, "w"))
	  for i=1,#data do
		  local j = 1
		  for key,coll in pairs(data[i]) do
			  if j>1 then file:write(sep) end
			  if type(coll) == 'table' then
				coll = tostring(coll[1])
			  end
			  file:write(coll)
			  j = j +1
		  end
		  file:write('\n')
	  end
	  file:close()
end

-- get filename of Path (the value after the last '/')  
function getfile(path, sep)
	local n
	path, n = path:gsub('\\','/')
	sep = sep or '/'
	path = path:reverse()
	local index = 0

	for i = 1, path:len() do
	local letter = path:sub(i,i ) 
		if (letter == sep) then
			--print (index)
			index = i
			--print (index)
			break
		end
	end
	path = path:sub(1,index-1)
	path = path:reverse()
	--outputToLog(path)
	return path
end

-- get the mime_type of a file
-- assuming only jpg or png files used for export and the real mime-type and file-extension match
--  @param string file : the complete path or filename with extension
--  @return string mime-type of the file 'mime/jpeg' or 'mime/png'
function getMime(file)
    local base = ''
    local mime = 'image/jpeg'
    base = getfile(file)
    base, ext = SplitFilename(base)
    ext = string.lower( ext )

    if ext == 'png' then
        mime = 'image/png'
    elseif ext == 'webp'  then
        mime = 'image/webp'
    end

    return mime
end

-- split string by given seperator
function strsplit(string, sSeparator, nMax, bRegexp)
	
    if sSeparator == '' then
        sSeparator = ','
    end

    if nMax and nMax < 1 then
        nMax = nil
    end

    local aRecord = {}

    if string == nil or string == 'nil' then
        return aRecord
    end

    if string:len() > 0 then
        local bPlain = not bRegexp
        nMax = nMax or -1

        local nField, nStart = 1, 1
        local nFirst,nLast = string:find(sSeparator, nStart, bPlain)
        while nFirst and nMax ~= 0 do
            aRecord[nField] = string:sub(nStart, nFirst-1)
            nField = nField+1
            nStart = nLast+1
            nFirst,nLast = string:find(sSeparator, nStart, bPlain)
            nMax = nMax-1
        end
        aRecord[nField] = string:sub(nStart)
    end

    return aRecord
end

---------------------------------------------------------------------
-- read sqlite3.exe result to table, result stored in *.txt, seperated by '|'
function sqlread(path, sep, tonum, null)
	tonum = tonum or true
    sep = sep or ','
    null = null or ''
    local csvFile = {}
    local fields = {}
    local file = assert(io.open(path, "r"))
    for line in file:lines() do
        fields = strsplit(line, sep)
        if tonum then -- convert numeric fields to numbers
            for i=1,#fields do
                local field = fields[i]
                if field == '' then
                    field = null
                end
                fields[i] = tonumber(field) or field
            end
        end
        table.insert(csvFile, fields)
    end
    file:close()
    return csvFile
end

-- source: https://stackoverflow.com/questions/34618946/lua-base64-encode
-- encoding
function encb64(data)
    local b='ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/' -- You will need this for encoding/decoding
    return ((data:gsub('.', function(x) 
        local r,b='',x:byte()
        for i=8,1,-1 do r=r..(b%2^i-b%2^(i-1)>0 and '1' or '0') end
        return r;
    end)..'0000'):gsub('%d%d%d?%d?%d?%d?', function(x)
        if (#x < 6) then return '' end
        local c=0
        for i=1,6 do c=c+(x:sub(i,i)=='1' and 2^(6-i) or 0) end
        return b:sub(c+1,c+1)
    end)..({ '', '==', '=' })[#data%3+1])
end

-- decoding
function decb64(data)
    local b='ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/' -- You will need this for encoding/decoding
    data = string.gsub(data, '[^'..b..'=]', '')
    return (data:gsub('.', function(x)
        if (x == '=') then return '' end
        local r,f='',(b:find(x)-1)
        for i=6,1,-1 do r=r..(f%2^i-f%2^(i-1)>0 and '1' or '0') end
        return r;
    end):gsub('%d%d%d?%d?%d?%d?%d?%d?', function(x)
        if (#x ~= 8) then return '' end
        local c=0
        for i=1,8 do c=c+(x:sub(i,i)=='1' and 2^(8-i) or 0) end
            return string.char(c)
    end))
end

function mytonumber( value )
    if type(value) == 'number' then
        return tonumber( value )
    else
        return 'nil'
    end
end

-- wird nach dem Aufrufen einer neuen Collection aufgerufen
-- check wether new Collection name is OK or fullfills the requirements
function checkfolder( proposedName )
    -- WP-StandardFolder nicht erlauben 
    -- WP erlaubt das: [a-zA-Z0-9\\/\\-_]*
    local first = string.sub(proposedName,1,1)
    local last = string.sub(proposedName, #proposedName, #proposedName)
    local wpcatsub = string.match(proposedName, '%d%d%d%d/%d%d')
    if wpcatsub ~= nil then
        proposedName = string.gsub(proposedName,wpcatsub,'')
    end

    local b='ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_/'
    
    local count = 0
    for i=1, #proposedName do
        local letter = string.sub(proposedName,i,i)
        local k,l = string.find(b,letter)
        if k == l and mytonumber(k) ~= 'nil' then 
            count = count + 1 
        end
    end

    if count ~= #proposedName then
        return false, 'Dont use other characters than a-z, A-Z, 0-9, / - _'
    elseif first == '/' or first == '\\' or last == '/' or last == '\\'  then
      return false, 'No limiting slashes allowed'
    elseif proposedName == '' or wpcatsub ~=nil then
      return false, 'Dont use WP Standard-Folder-Name'
    else 
      return true
    end
  
  end

  -- array ist einfache Tabelle als liste mit Stringwerten, wie von strsplit gelifert
  -- Annahme, dass der Wert nur einmal vorhanden ist
  function findValueInArray (array, key, depth)
    local result = 0
    
    if depth == '' or depth == nil then
        for i=1, #array do
            if array[i] == key then
                result = i
                break
            end
        end
    end

    if depth ==1 then
        for i=1, #array do
            if array[i] == key then
                result = i
                break
            end
        end
    end

    return result
end

-- suffix für url bestimmen je nach anzahl metadaten '?' oder '&'
function pre(n)
    
    local str = ''
    if n == 0 then
        str = '?'
    else
        str = '&'
    end
    return str
end

-- url encode bzw. sanitize für korrekten code im http-request
function urlencode(url)
    
    local char_to_hex = function(c)
        return string.format("%%%02X", string.byte(c))
    end

    if url == nil then
        return
    end

    url = url:gsub("\n", "\r\n")
    url = url:gsub("([^%w ])", char_to_hex)
    url = url:gsub(" ", "+")

    return url

end

function tableHasKey(table,key)
    return table[key] ~= nil
end

function round(value)
    if value % 1 < 0.5 then
        return math.floor(value)
    else
        return math.floor(value) + 1
    end
end

function isJSON(str)
    --local status = pcall(function() LrJson.decode(str) end)
    local status = pcall(function() json.decode(str) end)
    return status
end