local mf = require('Module:Mapframe')

-- Defaults
local DEFAULT_FRAME_WIDTH = "270"
local DEFAULT_FRAME_HEIGHT = "200"
local DEFAULT_ZOOM = 10
local DEFAULT_GEOMASK_STROKE_WIDTH = "1"
local DEFAULT_GEOMASK_STROKE_COLOR = "#777777"
local DEFAULT_GEOMASK_FILL = "#888888"
local DEFAULT_SHAPE_STROKE_WIDTH = "3"
local DEFAULT_SHAPE_STROKE_COLOR = "#FF0000"
local DEFAULT_SHAPE_FILL = "#606060"
local DEFAULT_LINE_STROKE_WIDTH = "5"
local DEFAULT_LINE_STROKE_COLOR = "#FF0000"
local DEFAULT_MARKER_COLOR = "#5E74F3"


-- Trim whitespace from args, and remove empty args
function trimArgs(argsTable)
	local cleanArgs = {}
	for key, val in pairs(argsTable) do
		if type(val) == 'string' then
			val = val:match('^%s*(.-)%s*$')
			if val ~= '' then
				cleanArgs[key] = val
			end
		else
			cleanArgs[key] = val
		end
	end
	return cleanArgs
end

function getBestStatement(item_id, property_id)
	if not(item_id) or not(mw.wikibase.isValidEntityId(item_id)) or not(mw.wikibase.entityExists(item_id)) then
		return false
	end
	local statements = mw.wikibase.getBestStatements(item_id, property_id)
	if not statements or #statements == 0 then
		return false
	end
	local hasNoValue = ( statements[1].mainsnak and statements[1].mainsnak.snaktype == 'novalue' )
	if hasNoValue then
		return false
	end
	return statements[1]
end

function hasWikidataProperty(item_id, property_id)
	return getBestStatement(item_id, property_id) and true or false
end

function getStatementValue(statement)
	return statement and statement.mainsnak and statement.mainsnak.datavalue and statement.mainsnak.datavalue.value or nil
end

function relatedEntity(item_id, property_id)
	local value = getStatementValue( getBestStatement(item_id, property_id) )
	return value and value.id or false
end

function idType(id)
	if not id then 
		return nil
	elseif mw.ustring.match(id, "[Pp]%d+") then
		return "property"
	elseif mw.ustring.match(id, "[Qq]%d+") then
		return "item"
	else
		return nil
	end
end

function getZoom(value, unit)
	local length_km
	if unit == 'km' then
		length_km = tonumber(value)
	elseif unit == 'mi' then
		length_km = tonumber(value)*1.609344
	elseif unit == 'km2' then
		length_km = math.sqrt(tonumber(value))
	elseif unit == 'mi2' then
		length_km = math.sqrt(tonumber(value))*1.609344
	end
	-- max for zoom 2 is 6400km, for zoom 3 is 3200km, for zoom 4 is 1600km, etc
	local zoom = math.floor(8 - (math.log10(length_km) - 2)/(math.log10(2)))
	-- limit to values below 17
	zoom = math.min(17, zoom)
	-- take off 1 when calculated from area, to account for unusual shapes
	if unit == 'km2' or unit == 'mi2' then
		zoom = zoom - 1
	end
	-- minimum value is 1
	return math.max(1, zoom)
end

local p = {}

p.main = function(frame)
	local parent = frame.getParent(frame)
	local parentArgs = parent.args
	local mapframe = p._main(parentArgs)
	return frame:preprocess(mapframe)
end

p._main = function(_config)
	-- `config` is the args passed to this module
	local config = trimArgs(_config)
	
	-- Use wikidata by default
	local useWikidata = true
	-- Do not use wikidata when coords are specified, unless explicitly set
	if config.coord then
		useWikidata = config.wikidata and true or false
	end
	
	-- Require wikidata item, or specified coords
	local wikidataId = config.id or mw.wikibase.getEntityIdForCurrentPage()
	if not(wikidataId) and not(config.coord) then
		return ''
	end

	-- Require coords (specified or from wikidata), so that map will be centred somewhere
	-- (P625 = coordinate location)
	local hasCoordinates = hasWikidataProperty(wikidataId, 'P625') or config.coordinates or config.coord
	if not hasCoordinates then  
		return ''
	end

	-- `args` is the arguments which will be passed to the mapframe module
	local args = {}

	-- Some defaults/overrides for infobox presentation
	args.display = "inline"
	args.frame = "yes"
	args.plain = "yes"
	args["frame-width"]  = config["frame-width"] or DEFAULT_FRAME_WIDTH
	args["frame-height"] = config["frame-height"] or DEFAULT_FRAME_HEIGHT
	args["frame-align"]  = "center"

	args["frame-coord"] = config["frame-coordinates"] or config["frame-coord"] or ""
	-- Note: config["coordinates"] or config["coord"] should not be used for the alignment of the frame;
	-- see talk page ( https://en.wikipedia.org/wiki/Special:Diff/876492931 )

	-- deprecated lat and long parameters
	args["frame-lat"]    = config["frame-lat"] or config["frame-latitude"] or ""
	args["frame-long"]   = config["frame-long"] or config["frame-longitude"] or ""

	-- Calculate zoom from length or area (converted to km or km2)
	if config.length_km then
		args.zoom = getZoom(config.length_km, 'km')
	elseif config.length_mi then
		args.zoom = getZoom(config.length_mi, 'mi')
	elseif config.area_km2 then
		args.zoom = getZoom(config.area_km2, 'km2')
	elseif config.area_mi2 then
		args.zoom = getZoom(config.area_mi2, 'mi2')
	else
		args.zoom = config.zoom or DEFAULT_ZOOM
	end
	
	-- Conditionals: whether point, geomask should be shown
	local hasOsmRelationId = hasWikidataProperty(wikidataId, 'P402') -- P402 is OSM relation ID
	local shouldShowPointMarker = not(hasOsmRelationId) or (config.marker and config.marker ~= 'none') or (config.coordinates or config.coord)
	local maskItem
	local maskType = idType(config.geomask)
	if maskType == 'item' then
		maskItem = config.geomask
	elseif maskType == "property" then
		maskItem = relatedEntity(wikidataId, config.geomask)
	end
	
	-- Keep track of arg numbering
	local argNumber = ''
	local function incrementArgNumber()
		if argNumber == '' then
			argNumber = 2
		else
			argNumber = argNumber + 1
		end
	end
	
	-- Geomask
	if maskItem then
		args["type"..argNumber] = "shape-inverse"
		args["id"..argNumber] = maskItem
		args["stroke-width"..argNumber] = config["geomask-stroke-width"] or DEFAULT_GEOMASK_STROKE_WIDTH
		args["stroke-color"..argNumber] = config["geomask-stroke-color"] or config["geomask-stroke-colour"] or DEFAULT_GEOMASK_STROKE_COLOR
		args["fill"..argNumber] = config["geomask-fill"] or DEFAULT_GEOMASK_FILL
		-- Recalculate zoom based on mask area, if available, and not set in config
		if not config.zoom then
			local maskArea = getStatementValue( getBestStatement(maskItem, 'P2046') )
			if maskArea and maskArea.amount then
				if maskArea.unit == 'http://www.wikidata.org/entity/Q712226' then -- square kilometre
					args.zoom = getZoom(maskArea.amount, 'km2')
				elseif maskArea.unit == 'http://www.wikidata.org/entity/Q232291' then -- square mile
					args.zoom = getZoom(maskArea.amount, 'mi2')
				end
			end
		end
		incrementArgNumber()
	end
	
	-- Shape
	if useWikidata then
		args["type"..argNumber] = "shape"
		if config.id then args["id"..argNumber] = config.id end
		args["stroke-width"..argNumber] = config["shape-stroke-width"] or config["stroke-width"] or DEFAULT_SHAPE_STROKE_WIDTH
		args["stroke-color"..argNumber] = config["shape-stroke-color"] or config["shape-stroke-colour"] or config["stroke-color"] or config["stroke-colour"] or DEFAULT_SHAPE_STROKE_COLOR
		args["fill"..argNumber] = config["shape-fill"] or DEFAULT_SHAPE_FILL
		incrementArgNumber()
	end
	
	-- Line
	if useWikidata then
		args["type"..argNumber] = "line"
		if config.id then args["id"..argNumber] = config.id end
		args["stroke-width"..argNumber] = config["line-stroke-width"] or config["stroke-width"] or DEFAULT_LINE_STROKE_WIDTH
		args["stroke-color"..argNumber] = config["line-stroke-color"] or config["line-stroke-colour"] or config["stroke-color"] or config["stroke-colour"] or DEFAULT_LINE_STROKE_COLOR
		incrementArgNumber()
	end

	-- Point
	if shouldShowPointMarker then
		args["type"..argNumber] = "point"
		if config.id then args["id"..argNumber] = config.id end
		if config.coord then args["coord"..argNumber] = config.coord end
		if config.marker then args["marker"..argNumber] = config.marker end
		args["marker-color"..argNumber] = config["marker-color"] or config["marker-colour"] or DEFAULT_MARKER_COLOR
		incrementArgNumber()
	end

	local mapframe = mf._main(args)
	local tracking = hasOsmRelationId and '' or '[[Category:Infobox mapframe withoot OSM relation ID on Wikidata]]'
	return mapframe .. tracking
end

return p