local getArgs = require('Module:Arguments').getArgs
local p = {}

function dbg(v, msg)
    mw.log((msg or '') .. mw.text.jsonEncode(v))
end

-- Parse all unnamed string parameters in a form of "latitude, longitude" into the real number pairs
function getSequence(args)
    local coords = {}
    for ind, val in pairs( args ) do
        if type(ind) == "number" then
            local valid = false
            local val2 = mw.text.split( val, ',', true )
            -- allow for elevation
            if #val2 >= 2 and #val2 <= 3 then
                local lat = tonumber(val2[1])
                local lon = tonumber(val2[2])
                if lat ~= nil and lon ~= nil then
                    table.insert(coords, { lon, lat } )
                    valid = true
                end
            end
            if not valid then error('Unnamed parameter #' .. ind .. ' "' .. val .. '" is not recognized as a valid "latitude,longitude" value') end
        end
    end
    return coords
end

--   See http://geojson.org/geojson-spec.html
-- Convert a comma and semicolon separated numbers into geojson coordinate arrays
-- Each geotype expects a certain array depth:
--   Point           - [ lon, lat ]  All other types use point as the basic type
--   MultiPoint      - array of points: [ point, ... ]
--   LineString      - array of 2 or more points: [ point, point, ... ]
--   MultiLineString - array of LineStrings: [ [ point, point, ... ], ... ]
--   Polygon         - [ [ point, point, point, point, ... ], ... ]
--                     each LinearRing is an array of 4 or more points, where first and last must be the same
--                     first LinearRing is the exterior ring, subsequent rings are holes in it
--   MultiPolygon    - array of Polygons: [ [ [ point, point, point, point, ... ], ... ], ... ]
--
-- For example, for the LineString, data "p1;p2;p3" would be converted to [p1,p2,p3] (each "p" is a [lon,lat] value)
-- LineString has the depth of "1" -- array of points (each point being a two value array)
-- For Polygon, the same sequence "p1;p2;p3" would be converted to [[p1,p2,p3]]
-- Which is an array of array of points. But sometimes we need to specify two subarrays of points:
-- [[p1,p2],[p3]] (last point is in a separate array), and we do it with "p1;p2;;p3"
-- Similarly, for MultiPolygon, "p1;p2;;;p3" would generate [[[p1,p2]],[[p3]]]
--
function p.parseGeoSequence(args)
    local result = p._parseGeoSequence(args)
    if type(result) == 'string' then error(result) end
    return result
end

function p._parseGeoSequence(args)
    local allTypes = {
        -- how many nested array levels until we get to the Point,
        -- second is the minimum number of values each Points array must have
        Point           = { 1, 1 },
        MultiPoint      = { 1, 0 },
        LineString      = { 1, 2 },
        MultiLineString = { 2, 2 },
        Polygon         = { 2, 4 },
        MultiPolygon    = { 3, 4 },
    }

    if not allTypes[args.geotype] then return ('Unknown geotype ' .. args.geotype) end
    local levels, min = unpack(allTypes[args.geotype])

    local result
    result = {}
    for i = 1, levels do result[i] = {} end
    local gap = 0

    -- Example for levels==3, converting "p1 ; p2 ; ; ; p3 ; ; p4" => [[[p1, p2]], [[p3],[p4]]]
    -- This function will be called after each gap, and all values are done, so the above will call:
    -- before p3:  gap=2, [],[],[p1,p2]            => [[[p1,p2]]],[],[]
    -- before p4:  gap=1, [[[p1,p2]]],[],[p3]      => [[[p1,p2]]],[[p3]]],[]
    -- the end,    gap=2, [[[p1,p2]]],[[p3]]],[p4] => [[[p1,p2]],[[p3],[p4]]],[],[]
    -- Here, convert at "p1 ; ; " from [[],[p1]]
    local closeArrays = function (gap)
        if #result[levels] < min then
            error('Each points array must be at least ' .. min .. ' values')
        elseif min == 1 and #result[levels] ~= 1 then
            -- Point
            error('Point must have exactly one data point')
        end
        -- attach arrays in reverse order to the higher order ones
        for i = levels, levels-gap+1, -1 do
            table.insert(result[i-1], result[i])
            result[i] = {}
        end
        return 0
    end

    local usedSequence = false
    for val in mw.text.gsplit(args.data, ';', true) do
        local val2 = mw.text.split(val, ',', true)
        -- allow for elevation
        if #val2 >= 2 and #val2 <= 3 and not usedSequence then
            if gap > 0 then gap = closeArrays(gap) end
            local lat = tonumber(val2[1])
            local lon = tonumber(val2[2])
            if lat == nil or lon == nil then return ('Bad data value "' .. val .. '"') end
            table.insert(result[levels], { lon, lat } )
        else
            val = mw.text.trim(val)
            if val == '' then
                usedSequence = false
                gap = gap + 1
                if (gap >= levels) then return ('Data must not skip more than ' .. levels-1 .. ' values') end
            elseif usedSequence then
                return ('Coordinates may not be added right after the named sequence')
            else
                if gap > 0 then
                    gap = closeArrays(gap)
                elseif #result[levels] > 0 then
                    return ('Named sequence "' .. val .. '" cannot be used in the middle of the sequence')
                end

                -- Parse value as a sequence name. Eventually we can load data from external data sources
                if val == 'values' then
                    val = getSequence(args)
                elseif min == 4 and val == 'world' then
                    val = ((36000,-180}, {36000,180}, {-36000,180}, {-36000,-180}, {36000,-180))
                elseif tonumber(val) ~= nil then
                    return ('Not a valid coordinate or a sequence name: ' .. val)
                else
                    return ('Sequence "' .. val .. '" is not known. Try "values" or "world" (for Polygons), or specify values as lat,lon;lat,lon;... pairs')
                end
                result[levels] = val
                usedSequence = true
            end
        end
    end
    -- allow one empty last value (some might close the list with an extra semicolon)
    if (gap > 1) then return ('Data values must not have blanks at the end') end
    closeArrays(levels-1)
    return args.geotype == 'Point' and result[1][1] or result[1]
end

-- Run this function to check that the above works ok
function p.parseGeoSequenceTest()
    local testSeq = function(data, expected)
        local result = getSequence(data)
        if type(result) == 'table' then
            local actual = mw.text.jsonEncode(result)
            result = actual ~= expected and 'data="' .. mw.text.jsonEncode(data) .. '", actual="' .. actual .. '", expected="' .. expected .. '"<br>\n' or ''
        else
            result = result .. '<br>\n'
        end
        return result
    end
    local test = function(geotype, data, expected, values)
        values = values or {}
        values.geotype = geotype;
        values.data = data;
        local result = p._parseGeoSequence(values)
        if type(result) == 'table' then
            local actual = mw.text.jsonEncode(result)
            result = actual ~= expected and 'geotype="' .. geotype .. '", data="' .. data .. '", actual="' .. actual .. '", expected="' .. expected .. '"<br>\n' or ''
        else
            result = 'geotype="' .. geotype .. '", data="' .. data .. '", error="' .. result .. '<br>\n'
        end
        return result
    end
    local values = {' 9 , 8 ','7,6'}
    local result = '' ..
            testSeq({}, '[]') ..
            testSeq({'\t\n 1 \r,-10'}, '[[-10,1]]') ..
            testSeq(values, '[[8,9],[6,7]]') ..
            test('Point', '1,2', '[2,1]') ..
            test('MultiPoint', '1,2;3,4;5,6', '[[2,1],[4,3],[6,5]]') ..
            test('LineString', '1,2;3,4', '[[2,1],[4,3]]') ..
            test('MultiLineString', '1,2;3,4', '[[[2,1],[4,3]]]') ..
            test('MultiLineString', '1,2;3,4;;5,6;7,8', '[[[2,1],[4,3]],[[6,5],[8,7]]]') ..
            test('Polygon', '1,2;3,4;5,6;1,2', '[[[2,1],[4,3],[6,5],[2,1]]]') ..
            test('MultiPolygon', '1,2;3,4;5,6;1,2', '[[[[2,1],[4,3],[6,5],[2,1]]]]') ..
            test('MultiPolygon', '1,2;3,4;5,6;1,2;;11,12;13,14;15,16;11,12', '[[[[2,1],[4,3],[6,5],[2,1]],[[12,11],[14,13],[16,15],[12,11]]]]') ..
            test('MultiPolygon', '1,2;3,4;5,6;1,2;;;11,12;13,14;15,16;11,12', '[[[[2,1],[4,3],[6,5],[2,1]]],[[[12,11],[14,13],[16,15],[12,11]]]]') ..
            test('MultiPolygon', '1,2;3,4;5,6;1,2;;;11,12;13,14;15,16;11,12;;21,22;23,24;25,26;21,22', '[[[[2,1],[4,3],[6,5],[2,1]]],[[[12,11],[14,13],[16,15],[12,11]],[[22,21],[24,23],[26,25],[22,21]]]]') ..
            test('MultiLineString', 'values;;1,2;3,4', '[[[8,9],[6,7]],[[2,1],[4,3]]]', values) ..
            test('Polygon', 'world;;world', '[[[36000,-180],[36000,180],[-36000,180],[-36000,-180],[36000,-180]],[[36000,-180],[36000,180],[-36000,180],[-36000,-180],[36000,-180]]]') ..
            ''
    return result ~= '' and result or 'Tests passed'
end


function p._tag(args)
    local tagname = args.type or 'maplink'
    if tagname ~= 'maplink' and tagname ~= 'mapframe' then error('unknown type "' .. tagname .. '"') end

    local geojson
    local tagArgs = {
        text = args.text,
        zoom = tonumber(args.zoom),
        latitude = tonumber(args.latitude),
        longitude = tonumber(args.longitude),
        class = args.class,
    }
    if tagname == 'mapframe' then
        tagArgs.width = args.width == nil and 420 or args.width
        tagArgs.height = args.height == nil and 420 or args.height
        tagArgs.align = args.align == nil and 'right' or args.align
    elseif not args.class and (args.text == '' or args.text == '""') then
		-- Hide pushpin icon in front of an empty text link
		tagArgs.class = 'no-icon'
    end

    if args.data == '' then args.data = nil end
    if (not args.geotype) ~= (not args.data) then
        -- one is given, but not the other
        if args.data then
            error('Parameter "data" is given, but "geotype" is not set. Use one of these: Point, MultiPoint, LineString, MultiLineString, Polygon, MultiPolygon')
        elseif args.geotype == "Point" and tagArgs.latitude ~= nil and tagArgs.longitude ~= nil then
            -- For Point geotype, it is enough to set latitude and logitude, and data will be set up automatically
            args.data = tagArgs.latitude .. ',' .. tagArgs.longitude
        else
            error('Parameter data must be set. Use "values" to use all unnamed parameters as coordinates (lat,lon|lat,lon|...), "world" for the whole world, a combination to make a mask, e.g. "world;;values", or direct values "lat,lon;lat,lon..." with ";" as value separator')
        end
    end

    -- Kartographer can now automatically calculate needed zoom & lat/long based on the data provided
    -- Current version ignores mapmasks, but that will also be fixed soon.  Leaving this for now, but can be removed if all is good.
    -- tagArgs.zoom = tagArgs.zoom == nil and 14 or tagArgs.zoom
    -- tagArgs.latitude = tagArgs.latitude == nil and 51.47766 or tagArgs.latitude
    -- tagArgs.longitude = tagArgs.longitude == nil and -0.00115 or tagArgs.longitude

	if args.image then
		args.description = (args.description or '') .. '[[file:' .. args.image .. '|300px]]'
	end

    if args.geotype then
        geojson = {
            type = "Feature",
            properties = {
                title = args.title,
                description = args.description,
                ['marker-size'] = args['marker-size'],
                ['marker-symbol'] = args['marker-symbol'],
                ['marker-color'] = args['marker-color'],
                stroke = args.stroke,
                ['stroke-opacity'] = tonumber(args['stroke-opacity']),
                ['stroke-width'] = tonumber(args['stroke-width']),
                fill = args.fill,
                ['fill-opacity'] = tonumber(args['fill-opacity']),
            },
            geometry = {
                type = args.geotype,
                coordinates = p.parseGeoSequence(args)
            }
        }
    end

    if args.debug ~= nil then
        local html = mw.html.create(tagname, not geojson and {selfClosing=true} or nil)
        :attr(tagArgs)
        if geojson then
            html:wikitext( mw.text.jsonEncode(geojson, mw.text.JSON_PRETTY) )
        end
        return 'syntaxhighlight', tostring(html) .. mw.text.jsonEncode(args, mw.text.JSON_PRETTY), { lang = 'json' }
    end

    return tagname, geojson and mw.text.jsonEncode(geojson) or '', tagArgs
end

function p.tag(frame)
    local args = getArgs(frame)
    local tag, geojson, tagArgs = p._tag(args)
    return frame:extensionTag(tag, geojson, tagArgs)
end

function p.tagForGeoshapeUsingWikidataItemId(frame)
    local args = getArgs(frame)
    local tagname = args.type or 'maplink'
    if tagname ~= 'maplink' and tagname ~= 'mapframe' then error('unknown type "' .. tagname .. '"') end
 	local tagArgs = {
        text = args.text,
        class = args.class
    }
    if tagname == 'mapframe' then
        tagArgs.width = args.width == nil and 420 or args.width
        tagArgs.height = args.height == nil and 420 or args.height
        tagArgs.align = args.align == nil and 'right' or args.align
    end
 
    local qid = args.qid
    if not qid then
    	qid = mw.wikibase.getEntityIdForCurrentPage()
    end
    if qid then
    	--TODO: récupérer latitude et longitude depuis Wikidata ?
    	return frame:extensionTag(tagname, mw.text.jsonEncode({
    		{['type'] = 'ExternalData', ['service'] = 'geoshape', ['ids'] = mw.text.trim(qid)},
    		{['type'] = 'ExternalData', ['service'] = 'geoline', ['ids'] = mw.text.trim(qid)}
    	}), tagArgs)
    else
    	return error('No Wikidata id found')
    end
end

return p