-- Data processing based on openmaptiles.org schema
-- https://openmaptiles.org/schema/
-- Copyright (c) 2016, KlokanTech.com & OpenMapTiles contributors.
-- Used under CC-BY 4.0

--------
-- Alter these lines to control which languages are written for place/streetnames
--
-- Preferred language can be (for example) "en" for English, "de" for German, or nil to use OSM's name tag:
preferred_language = nil
-- This is written into the following vector tile attribute (usually "name:latin"):
preferred_language_attribute = "name:latin"
-- If OSM's name tag differs, then write it into this attribute (usually "name_int"):
default_language_attribute = "name_int"
-- Also write these languages if they differ - for example, { "de", "fr" }
additional_languages = {}
--------

-- Enter/exit Tilemaker
function init_function()
end

function exit_function()
end

-- Implement Sets in tables
function Set(list)
    local set = {}
    for _, l in ipairs(list) do set[l] = true end
    return set
end

-- Meters per pixel if tile is 256x256
ZRES5                 = 4891.97
ZRES6                 = 2445.98
ZRES7                 = 1222.99
ZRES8                 = 611.5
ZRES9                 = 305.7
ZRES10                = 152.9
ZRES11                = 76.4
ZRES12                = 38.2
ZRES13                = 19.1

-- The height of one floor, in meters
BUILDING_FLOOR_HEIGHT = 3.66
-- Used to express that a feature should not end up the vector tiles
INVALID_ZOOM          = 99

-- Process node/way tags
aerodromeValues       = Set { "international", "public", "regional", "military", "private" }
pavedValues           = Set { "paved", "asphalt", "cobblestone", "concrete", "concrete:lanes", "concrete:plates", "metal", "paving_stones", "sett", "unhewn_cobblestone", "wood" }
unpavedValues         = Set { "unpaved", "compacted", "dirt", "earth", "fine_gravel", "grass", "grass_paver", "gravel", "gravel_turf", "ground", "ice", "mud", "pebblestone", "salt", "sand", "snow", "woodchips" }

-- Process node tags

node_keys             = { "addr:housenumber", "aerialway", "aeroway", "amenity", "barrier", "highway", "historic",
    "leisure", "natural", "office", "place", "railway", "shop", "sport", "tourism", "waterway" }

-- Get admin level which the place node is capital of.
-- Returns nil in case of invalid capital and for places which are not capitals.
function capitalLevel(capital)
    local capital_al = tonumber(capital) or 0
    if capital == "yes" then
        capital_al = 2
    end
    if capital_al == 0 then
        return nil
    end
    return capital_al
end

-- Calculate rank for place nodes
-- place: value of place=*
-- popuplation: population as number
-- capital_al: result of capitalLevel()
function calcRank(place, population, capital_al)
    local rank = 0
    if capital_al and capital_al >= 2 and capital_al <= 4 then
        rank = capital_al
        if population > 3 * 10 ^ 6 then
            rank = rank - 2
        elseif population > 1 * 10 ^ 6 then
            rank = rank - 1
        elseif population < 100000 then
            rank = rank + 2
        elseif population < 50000 then
            rank = rank + 3
        end
        -- Safety measure to avoid place=village/farm/... appear early (as important capital) because a mapper added capital=yes/2/3/4
        if place ~= "city" then
            rank = rank + 3
            -- Decrease rank further if it is not even a town.
            if place ~= "town" then
                rank = rank + 2
            end
        end
        return rank
    end
    if place ~= "city" and place ~= "town" then
        return nil
    end
    if population > 3 * 10 ^ 6 then
        return 1
    elseif population > 1 * 10 ^ 6 then
        return 2
    elseif population > 500000 then
        return 3
    elseif population > 200000 then
        return 4
    elseif population > 100000 then
        return 5
    elseif population > 75000 then
        return 6
    elseif population > 50000 then
        return 7
    elseif population > 25000 then
        return 8
    elseif population > 10000 then
        return 9
    end
    return 10
end

function node_function()
    -- Write 'aerodrome_label'
    local aeroway = Find("aeroway")
    if aeroway == "aerodrome" then
        Layer("aerodrome_label", false)
        SetNameAttributes()
        Attribute("iata", Find("iata"))
        SetEleAttributes()
        Attribute("icao", Find("icao"))

        local aerodrome_value = Find("aerodrome")
        local class
        if aerodromeValues[aerodrome_value] then class = aerodrome_value else class = "other" end
        Attribute("class", class)
    end
    -- Write 'housenumber'
    local housenumber = Find("addr:housenumber")
    if housenumber ~= "" then
        Layer("housenumber", false)
        Attribute("housenumber", housenumber)
    end

    -- Write 'place'
    -- note that OpenMapTiles has a rank for countries (1-3), states (1-6) and cities (1-10+);
    --   we could potentially approximate it for cities based on the population tag
    local place = Find("place")
    if place ~= "" then
        local mz = 13
        local pop = tonumber(Find("population")) or 0
        local capital = capitalLevel(Find("capital"))
        local rank = calcRank(place, pop, capital)

        if place == "continent" then
            mz = 0
        elseif place == "country" then
            if pop > 50000000 then
                rank = 1; mz = 1
            elseif pop > 20000000 then
                rank = 2; mz = 2
            else
                rank = 3; mz = 3
            end
        elseif place == "state" then
            mz = 4
        elseif place == "province" then
            mz = 5
        elseif place == "city" then
            mz = 5
        elseif place == "town" and pop > 8000 then
            mz = 7
        elseif place == "town" then
            mz = 8
        elseif place == "village" and pop > 2000 then
            mz = 9
        elseif place == "village" then
            mz = 10
        elseif place == "borough" then
            mz = 10
        elseif place == "suburb" then
            mz = 11
        elseif place == "quarter" then
            mz = 12
        elseif place == "hamlet" then
            mz = 12
        elseif place == "neighbourhood" then
            mz = 13
        elseif place == "isolated_dwelling" then
            mz = 13
        elseif place == "locality" then
            mz = 13
        elseif place == "island" then
            mz = 12
        end

        Layer("place", false)
        Attribute("class", place)
        MinZoom(mz)
        if rank then AttributeNumeric("rank", rank) end
        if capital then AttributeNumeric("capital", capital) end
        if place == "country" then
            local iso_a2 = Find("ISO3166-1:alpha2")
            while iso_a2 == "" do
                local rel, role = NextRelation()
                if not rel then break end
                if role == 'label' then
                    iso_a2 = FindInRelation("ISO3166-1:alpha2")
                end
            end
            Attribute("iso_a2", iso_a2)
        end
        SetNameAttributes()
        return
    end

    -- Write 'poi'
    local rank, class, subclass = GetPOIRank()
    if rank then WritePOI(class, subclass, rank) end

    -- Write 'mountain_peak' and 'water_name'
    local natural = Find("natural")
    if natural == "peak" or natural == "volcano" then
        Layer("mountain_peak", false)
        SetEleAttributes()
        AttributeNumeric("rank", 1)
        Attribute("class", natural)
        SetNameAttributes()
        return
    end
    if natural == "bay" then
        Layer("water_name", false)
        SetNameAttributes()
        return
    end
end

-- Process way tags

majorRoadValues    = Set { "motorway", "trunk", "primary" }
z9RoadValues       = Set { "secondary", "motorway_link", "trunk_link" }
z10RoadValues      = Set { "primary_link", "secondary_link" }
z11RoadValues      = Set { "tertiary", "tertiary_link", "busway", "bus_guideway" }
-- On zoom 12, various road classes are merged into "minor"
z12MinorRoadValues = Set { "unclassified", "residential", "road", "living_street" }
z12OtherRoadValues = Set { "raceway" }
z13RoadValues      = Set { "track", "service" }
manMadeRoadValues  = Set { "pier", "bridge" }
pathValues         = Set { "footway", "cycleway", "bridleway", "path", "steps", "pedestrian", "platform" }
linkValues         = Set { "motorway_link", "trunk_link", "primary_link", "secondary_link", "tertiary_link" }
pavedValues        = Set { "paved", "asphalt", "cobblestone", "concrete", "concrete:lanes", "concrete:plates", "metal", "paving_stones", "sett", "unhewn_cobblestone", "wood" }
unpavedValues      = Set { "unpaved", "compacted", "dirt", "earth", "fine_gravel", "grass", "grass_paver", "gravel", "gravel_turf", "ground", "ice", "mud", "pebblestone", "salt", "sand", "snow", "woodchips" }
-- disused added for the REAKT track
railwayClasses     = {
    rail = "rail",
    narrow_gauge = "rail",
    preserved = "rail",
    funicular = "rail",
    subway = "transit",
    light_rail =
    "transit",
    monorail = "transit",
    tram = "transit",
    disused = "rail"
}

aerowayBuildings   = Set { "terminal", "gate", "tower" }
landuseKeys        = Set { "school", "university", "kindergarten", "college", "library", "hospital",
    "railway", "cemetery", "military", "residential", "commercial", "industrial",
    "retail", "stadium", "pitch", "playground", "theme_park", "bus_station", "zoo" }
landcoverKeys      = {
    wood = "wood",
    forest = "wood",
    wetland = "wetland",
    beach = "sand",
    sand = "sand",
    dune = "sand",
    farmland = "farmland",
    farm = "farmland",
    orchard = "farmland",
    vineyard = "farmland",
    plant_nursery = "farmland",
    glacier = "ice",
    ice_shelf = "ice",
    bare_rock = "rock",
    scree = "rock",
    fell = "grass",
    grassland = "grass",
    grass = "grass",
    heath = "grass",
    meadow = "grass",
    allotments = "grass",
    park = "grass",
    village_green = "grass",
    recreation_ground = "grass",
    scrub = "grass",
    shrubbery = "grass",
    tundra = "grass",
    garden = "grass",
    golf_course = "grass",
    park = "grass"
}

-- POI key/value pairs: based on https://github.com/openmaptiles/openmaptiles/blob/master/layers/poi/mapping.yaml
poiTags            = {
    aerialway = Set { "station" },
    amenity = Set { "arts_centre", "bank", "bar", "bbq", "bicycle_parking", "bicycle_rental", "biergarten", "bus_station", "cafe", "cinema", "clinic", "college", "community_centre", "courthouse", "dentist", "doctors", "embassy", "fast_food", "ferry_terminal", "fire_station", "food_court", "fuel", "grave_yard", "hospital", "ice_cream", "kindergarten", "library", "marketplace", "motorcycle_parking", "nightclub", "nursing_home", "parking", "pharmacy", "place_of_worship", "police", "post_box", "post_office", "prison", "pub", "public_building", "recycling", "restaurant", "school", "shelter", "swimming_pool", "taxi", "telephone", "theatre", "toilets", "townhall", "university", "veterinary", "waste_basket" },
    barrier = Set { "bollard", "border_control", "cycle_barrier", "gate", "lift_gate", "sally_port", "stile", "toll_booth" },
    building = Set { "dormitory" },
    highway = Set { "bus_stop" },
    historic = Set { "monument", "castle", "ruins" },
    landuse = Set { "basin", "brownfield", "cemetery", "reservoir", "winter_sports" },
    leisure = Set { "dog_park", "escape_game", "garden", "golf_course", "ice_rink", "hackerspace", "marina", "miniature_golf", "park", "pitch", "playground", "sports_centre", "stadium", "swimming_area", "swimming_pool", "water_park" },
    railway = Set { "halt", "station", "subway_entrance", "train_station_entrance", "tram_stop" },
    shop = Set { "accessories", "alcohol", "antiques", "art", "bag", "bakery", "beauty", "bed", "beverages", "bicycle", "books", "boutique", "butcher", "camera", "car", "car_repair", "carpet", "charity", "chemist", "chocolate", "clothes", "coffee", "computer", "confectionery", "convenience", "copyshop", "cosmetics", "deli", "delicatessen", "department_store", "doityourself", "dry_cleaning", "electronics", "erotic", "fabric", "florist", "frozen_food", "furniture", "garden_centre", "general", "gift", "greengrocer", "hairdresser", "hardware", "hearing_aids", "hifi", "ice_cream", "interior_decoration", "jewelry", "kiosk", "lamps", "laundry", "mall", "massage", "mobile_phone", "motorcycle", "music", "musical_instrument", "newsagent", "optician", "outdoor", "perfume", "perfumery", "pet", "photo", "second_hand", "shoes", "sports", "stationery", "supermarket", "tailor", "tattoo", "ticket", "tobacco", "toys", "travel_agency", "video", "video_games", "watches", "weapons", "wholesale", "wine" },
    sport = Set { "american_football", "archery", "athletics", "australian_football", "badminton", "baseball", "basketball", "beachvolleyball", "billiards", "bmx", "boules", "bowls", "boxing", "canadian_football", "canoe", "chess", "climbing", "climbing_adventure", "cricket", "cricket_nets", "croquet", "curling", "cycling", "disc_golf", "diving", "dog_racing", "equestrian", "fatsal", "field_hockey", "free_flying", "gaelic_games", "golf", "gymnastics", "handball", "hockey", "horse_racing", "horseshoes", "ice_hockey", "ice_stock", "judo", "karting", "korfball", "long_jump", "model_aerodrome", "motocross", "motor", "multi", "netball", "orienteering", "paddle_tennis", "paintball", "paragliding", "pelota", "racquet", "rc_car", "rowing", "rugby", "rugby_league", "rugby_union", "running", "sailing", "scuba_diving", "shooting", "shooting_range", "skateboard", "skating", "skiing", "soccer", "surfing", "swimming", "table_soccer", "table_tennis", "team_handball", "tennis", "toboggan", "volleyball", "water_ski", "yoga" },
    tourism = Set { "alpine_hut", "aquarium", "artwork", "attraction", "bed_and_breakfast", "camp_site", "caravan_site", "chalet", "gallery", "guest_house", "hostel", "hotel", "information", "motel", "museum", "picnic_site", "theme_park", "viewpoint", "zoo" },
    waterway = Set { "dock" }
}

-- POI "class" values: based on https://github.com/openmaptiles/openmaptiles/blob/master/layers/poi/poi.yaml
poiClasses         = {
    townhall = "town_hall",
    public_building = "town_hall",
    courthouse = "town_hall",
    community_centre = "town_hall",
    golf = "golf",
    golf_course = "golf",
    miniature_golf = "golf",
    fast_food = "fast_food",
    food_court = "fast_food",
    park = "park",
    bbq = "park",
    bus_stop = "bus",
    bus_station = "bus",
    subway_entrance = "entrance",
    train_station_entrance = "entrance",
    camp_site = "campsite",
    caravan_site = "campsite",
    laundry = "laundry",
    dry_cleaning = "laundry",
    supermarket = "grocery",
    deli = "grocery",
    delicatessen = "grocery",
    department_store = "grocery",
    greengrocer = "grocery",
    marketplace = "grocery",
    books = "library",
    library = "library",
    university = "college",
    college = "college",
    hotel = "lodging",
    motel = "lodging",
    bed_and_breakfast = "lodging",
    guest_house = "lodging",
    hostel = "lodging",
    chalet = "lodging",
    alpine_hut = "lodging",
    dormitory = "lodging",
    chocolate = "ice_cream",
    confectionery = "ice_cream",
    post_box = "post",
    post_office = "post",
    cafe = "cafe",
    school = "school",
    kindergarten = "school",
    alcohol = "alcohol_shop",
    beverages = "alcohol_shop",
    wine = "alcohol_shop",
    bar = "bar",
    nightclub = "bar",
    marina = "harbor",
    dock = "harbor",
    car = "car",
    car_repair = "car",
    taxi = "car",
    hospital = "hospital",
    nursing_home = "hospital",
    clinic = "hospital",
    grave_yard = "cemetery",
    cemetery = "cemetery",
    attraction = "attraction",
    viewpoint = "attraction",
    biergarten = "beer",
    pub = "beer",
    music = "music",
    musical_instrument = "music",
    american_football = "stadium",
    stadium = "stadium",
    soccer = "stadium",
    art = "art_gallery",
    artwork = "art_gallery",
    gallery = "art_gallery",
    arts_centre = "art_gallery",
    bag = "clothing_store",
    clothes = "clothing_store",
    swimming_area = "swimming",
    swimming = "swimming",
    castle = "castle",
    ruins = "castle"
}
-- POI classes where class is the matching value and subclass is the value of a separate key
poiSubClasses      = { information = "information", place_of_worship = "religion", pitch = "sport" }
poiClassRanks      = {
    hospital = 1,
    railway = 2,
    bus = 3,
    attraction = 4,
    harbor = 5,
    college = 6,
    school = 7,
    stadium = 8,
    zoo = 9,
    town_hall = 10,
    campsite = 11,
    cemetery = 12,
    park = 13,
    library = 14,
    police = 15,
    post = 16,
    golf = 17,
    shop = 18,
    grocery = 19,
    fast_food = 20,
    clothing_store = 21,
    bar = 22
}
waterClasses       = Set { "river", "riverbank", "stream", "canal", "drain", "ditch", "dock" }
waterwayClasses    = Set { "stream", "river", "canal", "drain", "ditch" }

-- Scan relations for use in ways

function relation_scan_function()
    if Find("type") == "boundary" and Find("boundary") == "administrative" then
        Accept()
    end
end

function write_to_transportation_layer(minzoom, highway_class, subclass, ramp, service, is_rail, is_road, is_area)
    Layer("transportation", is_area)
    SetZOrder()
    Attribute("class", highway_class)
    if subclass and subclass ~= "" then
        Attribute("subclass", subclass)
    end
    AttributeNumeric("layer", tonumber(Find("layer")) or 0, accessMinzoom)
    SetBrunnelAttributes()
    -- We do not write any other attributes for areas.
    if is_area then
        SetMinZoomByAreaWithLimit(minzoom)
        return
    end
    MinZoom(minzoom)
    if ramp then AttributeNumeric("ramp", 1) end

    -- Service
    if (is_rail or highway_class == "service") and (service and service ~= "") then Attribute("service", service) end

    local accessMinzoom = 9
    if is_road then
        local oneway = Find("oneway")
        if oneway == "yes" or oneway == "1" then
            AttributeNumeric("oneway", 1)
        end
        if oneway == "-1" then
            -- **** TODO
        end
        local surface = Find("surface")
        local surfaceMinzoom = 12
        if pavedValues[surface] then
            Attribute("surface", "paved", surfaceMinzoom)
        elseif unpavedValues[surface] then
            Attribute("surface", "unpaved", surfaceMinzoom)
        end
        if Holds("access") then Attribute("access", Find("access"), accessMinzoom) end
        if Holds("bicycle") then Attribute("bicycle", Find("bicycle"), accessMinzoom) end
        if Holds("foot") then Attribute("foot", Find("foot"), accessMinzoom) end
        if Holds("horse") then Attribute("horse", Find("horse"), accessMinzoom) end
        AttributeBoolean("toll", Find("toll") == "yes", accessMinzoom)
        if Find("expressway") == "yes" then AttributeBoolean("expressway", true, 7) end
        if Holds("mtb_scale") then Attribute("mtb_scale", Find("mtb:scale"), 10) end
    end
end

-- Process way tags

function way_function()
    local route            = Find("route")
    local highway          = Find("highway")
    local waterway         = Find("waterway")
    local water            = Find("water")
    local building         = Find("building")
    local natural          = Find("natural")
    local historic         = Find("historic")
    local landuse          = Find("landuse")
    local leisure          = Find("leisure")
    local amenity          = Find("amenity")
    local aeroway          = Find("aeroway")
    local railway          = Find("railway")
    local service          = Find("service")
    local sport            = Find("sport")
    local shop             = Find("shop")
    local tourism          = Find("tourism")
    local man_made         = Find("man_made")
    local boundary         = Find("boundary")
    local aerialway        = Find("aerialway")
    local public_transport = Find("public_transport")
    local place            = Find("place")
    local is_closed        = IsClosed()
    local housenumber      = Find("addr:housenumber")
    local write_name       = false
    local construction     = Find("construction")
    local is_highway_area  = highway ~= "" and Find("area") == "yes" and is_closed

    -- Miscellaneous preprocessing
    if Find("disused") == "yes" then return end
    if boundary ~= "" and Find("protection_title") == "National Forest" and Find("operator") == "United States Forest Service" then return end
    if highway == "proposed" then return end
    if aerowayBuildings[aeroway] then
        building = "yes"; aeroway = ""
    end
    if landuse == "field" then landuse = "farmland" end
    if landuse == "meadow" and Find("meadow") == "agricultural" then landuse = "farmland" end

    if place == "island" then
        LayerAsCentroid("place")
        Attribute("class", place)
        MinZoom(10)
        local pop = tonumber(Find("population")) or 0
        local capital = capitalLevel(Find("capital"))
        local rank = calcRank(place, pop, nil)
        if rank then AttributeNumeric("rank", rank) end
        SetNameAttributes()
    end

    -- Boundaries within relations
    -- note that we process administrative boundaries as properties on ways, rather than as single relation geometries,
    --  because otherwise we get multiple renderings where boundaries are coterminous
    local admin_level = 11
    local isBoundary = false
    while true do
        local rel = NextRelation()
        if not rel then break end
        isBoundary = true
        admin_level = math.min(admin_level, tonumber(FindInRelation("admin_level")) or 11)
    end

    -- Boundaries in ways
    if boundary == "administrative" then
        admin_level = math.min(admin_level, tonumber(Find("admin_level")) or 11)
        isBoundary = true
    end

    -- Administrative boundaries
    -- https://openmaptiles.org/schema/#boundary
    if isBoundary and not (Find("maritime") == "yes") then
        local mz = 0
        if admin_level >= 3 and admin_level < 5 then
            mz = 4
        elseif admin_level >= 5 and admin_level < 7 then
            mz = 8
        elseif admin_level == 7 then
            mz = 10
        elseif admin_level >= 8 then
            mz = 12
        end

        Layer("boundary", false)
        AttributeNumeric("admin_level", admin_level)
        MinZoom(mz)
        -- disputed status (0 or 1). some styles need to have the 0 to show it.
        local disputed = Find("disputed")
        if disputed == "yes" then
            AttributeNumeric("disputed", 1)
        else
            AttributeNumeric("disputed", 0)
        end
    end

    -- Aerialways ('transportation' and 'transportation_name')
    if aerialway ~= "" then
        write_to_transportation_layer(12, "aerialway", aerialway, false, nil, false, false, is_closed)
        if HasNames() then
            Layer("transportation_name", false)
            MinZoom(12)
            SetNameAttributes()
            Attribute("class", "aerialway")
            Attribute("subclass", aerialway)
        end
    end

    -- Roads ('transportation' and 'transportation_name')
    if highway ~= "" or public_transport == "platform" then
        local access = Find("access")
        local surface = Find("surface")

        local h = highway
        local is_road = true
        if h == "" then
            h = public_transport
            is_road = false
        end
        local subclass = nil
        local under_construction = false
        if highway == "construction" and construction ~= "" then
            h = construction
            under_construction = true
        end
        local minzoom = INVALID_ZOOM
        if majorRoadValues[h] then
            minzoom = 4
        elseif h == "trunk" then
            minzoom = 5
        elseif highway == "primary" then
            minzoom = 7
        elseif z9RoadValues[h] then
            minzoom = 9
        elseif z10RoadValues[h] then
            minzoom = 10
        elseif z11RoadValues[h] then
            minzoom = 11
        elseif z12MinorRoadValues[h] then
            minzoom = 12
            subclass = h
            h = "minor"
        elseif z12OtherRoadValues[h] then
            minzoom = 12
        elseif z13RoadValues[h] then
            minzoom = 13
        elseif pathValues[h] then
            minzoom = 14
            subclass = h
            h = "path"
        end

        -- Links (ramp)
        local ramp = false
        if linkValues[h] then
            splitHighway = split(highway, "_")
            highway = splitHighway[1]; h = highway
            ramp = true
        end

        -- Construction
        if under_construction then
            h = h .. "_construction"
        end

        -- Drop underground platforms
        local layer = Find("layer")
        local layerNumeric = tonumber(layer)
        if not is_road and layerNumeric ~= nil and layerNumeric < 0 then
            minzoom = INVALID_ZOOM
        end

        -- Drop all areas except infrastructure for pedestrians handled above
        if is_highway_area and h ~= "path" then
            minzoom = INVALID_ZOOM
        end

        -- Write to layer
        if minzoom <= 14 then
            write_to_transportation_layer(minzoom, h, subclass, ramp, service, false, is_road, is_highway_area)

            -- Write names
            if not is_closed and (HasNames() or Holds("ref")) then
                if h == "motorway" then
                    minzoom = 7
                elseif h == "trunk" then
                    minzoom = 8
                elseif h == "primary" then
                    minzoom = 10
                elseif h == "secondary" then
                    minzoom = 11
                elseif h == "minor" or h == "track" or h == "tertiary" then
                    minzoom = 13
                else
                    minzoom = 14
                end
                Layer("transportation_name", false)
                MinZoom(minzoom)
                SetNameAttributes()
                Attribute("class", h)
                Attribute("network", "road") -- **** could also be us-interstate, us-highway, us-state
                if subclass then Attribute("subclass", highway) end
                local ref = Find("ref")
                if ref ~= "" then
                    Attribute("ref", ref)
                    AttributeNumeric("ref_length", ref:len())
                end
            end
        end
    end

    -- Railways ('transportation' and 'transportation_name')
    if railway ~= "" then
        local class = railwayClasses[railway]
        if class then
            local minzoom = 8
            Layer("transportation", false)
            -- filter disused tracks beside malente track
            local ref = Find("ref")
            local malenteRef = "1112"
            if railway == "disused" then
                if ref ~= malenteRef then
                    minzoom = 11
                end
            end
            -- Filter narrow_gauge track
            if railway == "narrow_gauge" then
                minzoom = 14
            end
            -- Filter historic
            local historic_rail = Find("historic")
            if historic_rail == "railway" then
                minzoom = 14
            end
            write_to_transportation_layer(minzoom, class, railway, false, service, true, false, is_closed)

            if HasNames() then
                Layer("transportation_name", false)
                SetNameAttributes()
                MinZoom(14)
                Attribute("class", class)
            end
        end
    end

    -- Pier
    if manMadeRoadValues[man_made] then
        write_to_transportation_layer(13, man_made, nil, false, nil, false, false, is_closed)
    end

    -- 'Ferry'
    if route == "ferry" then
        write_to_transportation_layer(9, "ferry", nil, false, nil, false, false, is_closed)

        if HasNames() then
            Layer("transportation_name", false)
            SetNameAttributes()
            MinZoom(12)
            Attribute("class", "ferry")
        end
    end

    -- 'Aeroway'
    if aeroway ~= "" then
        Layer("aeroway", is_closed)
        Attribute("class", aeroway)
        Attribute("ref", Find("ref"))
        write_name = true
    end

    -- 'aerodrome_label'
    if aeroway == "aerodrome" then
        LayerAsCentroid("aerodrome_label")
        SetNameAttributes()
        Attribute("iata", Find("iata"))
        SetEleAttributes()
        Attribute("icao", Find("icao"))

        local aerodrome = Find(aeroway)
        local class
        if aerodromeValues[aerodrome] then class = aerodrome else class = "other" end
        Attribute("class", class)
    end

    -- Set 'waterway' and associated
    if waterwayClasses[waterway] and not is_closed then
        if waterway == "river" and Holds("name") then
            Layer("waterway", false)
        else
            Layer("waterway_detail", false)
        end
        if Find("intermittent") == "yes" then AttributeNumeric("intermittent", 1) else AttributeNumeric("intermittent", 0) end
        Attribute("class", waterway)
        SetNameAttributes()
        SetBrunnelAttributes()
    elseif waterway == "boatyard" then
        Layer("landuse", is_closed); Attribute("class", "industrial"); MinZoom(12)
    elseif waterway == "dam" then
        Layer("building", is_closed)
    elseif waterway == "fuel" then
        Layer("landuse", is_closed); Attribute("class", "industrial"); MinZoom(14)
    end
    -- Set names on rivers
    if waterwayClasses[waterway] and not is_closed then
        if waterway == "river" and Holds("name") then
            Layer("water_name", false)
        else
            Layer("water_name_detail", false)
            MinZoom(14)
        end
        Attribute("class", waterway)
        SetNameAttributes()
    end

    -- Set 'building' and associated
    if building ~= "" then
        Layer("building", true)
        SetBuildingHeightAttributes()
        SetMinZoomByArea()
    end

    -- Set 'housenumber'
    if housenumber ~= "" then
        LayerAsCentroid("housenumber")
        Attribute("housenumber", housenumber)
    end

    -- Set 'water'
    if natural == "water" or leisure == "swimming_pool" or landuse == "reservoir" or landuse == "basin" or waterClasses[waterway] then
        if Find("covered") == "yes" or not is_closed then return end
        local class = "lake"; if waterway ~= "" then class = "river" end
        if class == "lake" and Find("wikidata") == "Q192770" then return end
        Layer("water", true)
        SetMinZoomByArea(way)
        Attribute("class", class)

        if Find("intermittent") == "yes" then Attribute("intermittent", 1) end
        -- we only want to show the names of actual lakes not every man-made basin that probably doesn't even have a name other than "basin"
        -- examples for which we don't want to show a name:
        --  https://www.openstreetmap.org/way/25958687
        --  https://www.openstreetmap.org/way/27201902
        --  https://www.openstreetmap.org/way/25309134
        --  https://www.openstreetmap.org/way/24579306
        if Holds("name") and natural == "water" and water ~= "basin" and water ~= "wastewater" then
            LayerAsCentroid("water_name_detail")
            SetNameAttributes()
            SetMinZoomByArea()
            Attribute("class", class)
        end

        return -- in case we get any landuse processing
    end

    -- Set 'landcover' (from landuse, natural, leisure)
    local l = landuse
    if l == "" then l = natural end
    if l == "" then l = leisure end
    if landcoverKeys[l] then
        Layer("landcover", true)
        SetMinZoomByArea()
        Attribute("class", landcoverKeys[l])
        if l == "wetland" then
            Attribute("subclass", Find("wetland"))
        else
            Attribute("subclass", l)
        end
        write_name = true

        -- Set 'landuse'
    else
        if l == "" then l = amenity end
        if l == "" then l = tourism end
        if landuseKeys[l] then
            Layer("landuse", true)
            Attribute("class", l)
            if l == "residential" then
                if Area() < ZRES8 ^ 2 then
                    MinZoom(8)
                else
                    SetMinZoomByArea()
                end
            else
                MinZoom(11)
            end
            write_name = true
        end
    end

    -- Parks
    -- **** name?
    if boundary == "national_park" then
        Layer("park", true); Attribute("class", boundary); SetNameAttributes()
    elseif leisure == "nature_reserve" then
        Layer("park", true); Attribute("class", leisure); SetNameAttributes()
    end

    -- POIs ('poi' and 'poi_detail')
    local rank, class, subclass = GetPOIRank()
    if rank then
        WritePOI(class, subclass, rank); return
    end

    -- Catch-all
    if (building ~= "" or write_name) and Holds("name") then
        LayerAsCentroid("poi_detail")
        SetNameAttributes()
        if write_name then rank = 6 else rank = 25 end
        AttributeNumeric("rank", rank)
    end
end

-- Remap coastlines
function attribute_function(attr, layer)
    if attr["featurecla"] == "Glaciated areas" then
        return { subclass = "glacier" }
    elseif attr["featurecla"] == "Antarctic Ice Shelf" then
        return { subclass = "ice_shelf" }
    elseif attr["featurecla"] == "Urban area" then
        return { class = "residential" }
    elseif layer == "ocean" then
        return { class = "ocean" }
    else
        return attr
    end
end

-- ==========================================================
-- Common functions

-- Write a way centroid to POI layer
function WritePOI(class, subclass, rank)
    local layer = "poi"
    if rank > 4 then layer = "poi_detail" end
    LayerAsCentroid(layer)
    SetNameAttributes()
    AttributeNumeric("rank", rank)
    Attribute("class", class)
    Attribute("subclass", subclass)
    -- layer defaults to 0
    AttributeNumeric("layer", tonumber(Find("layer")) or 0)
    -- indoor defaults to false
    AttributeBoolean("indoor", (Find("indoor") == "yes"))
    -- level has no default
    local level = tonumber(Find("level"))
    if level then
        AttributeNumeric("level", level)
    end
end

-- Check if there are name tags on the object
function HasNames()
    if Holds("name") then return true end
    local iname
    local main_written = name
    if preferred_language and Holds("name:" .. preferred_language) then return true end
    -- then set any additional languages
    for i, lang in ipairs(additional_languages) do
        if Holds("name:" .. lang) then return true end
    end
    return false
end

-- Set name attributes on any object
function SetNameAttributes()
    local name = Find("name"), iname
    local main_written = name
    -- if we have a preferred language, then write that (if available), and additionally write the base name tag
    if preferred_language and Holds("name:" .. preferred_language) then
        iname = Find("name:" .. preferred_language)
        Attribute(preferred_language_attribute, iname)
        if iname ~= name and default_language_attribute then
            Attribute(default_language_attribute, name)
        else
            main_written = iname
        end
    else
        Attribute(preferred_language_attribute, name)
    end
    -- then set any additional languages
    for i, lang in ipairs(additional_languages) do
        iname = Find("name:" .. lang)
        if iname == "" then iname = name end
        if iname ~= main_written then Attribute("name:" .. lang, iname) end
    end
end

-- Set ele and ele_ft on any object
function SetEleAttributes()
    local ele = Find("ele")
    if ele ~= "" then
        local meter = math.floor(tonumber(ele) or 0)
        local feet = math.floor(meter * 3.2808399)
        AttributeNumeric("ele", meter)
        AttributeNumeric("ele_ft", feet)
    end
end

function SetBrunnelAttributes()
    if Find("bridge") == "yes" or Find("man_made") == "bridge" then
        Attribute("brunnel", "bridge")
    elseif Find("tunnel") == "yes" then
        Attribute("brunnel", "tunnel")
    elseif Find("ford") == "yes" then
        Attribute("brunnel", "ford")
    end
end

-- Set minimum zoom level by area
function SetMinZoomByArea()
    SetMinZoomByAreaWithLimit(0)
end

-- Set minimum zoom level by area but not below given minzoom
function SetMinZoomByAreaWithLimit(minzoom)
    local area = Area()
    if minzoom <= 6 and area > ZRES5 ^ 2 then
        MinZoom(6)
    elseif minzoom <= 7 and area > ZRES6 ^ 2 then
        MinZoom(7)
    elseif minzoom <= 8 and area > ZRES7 ^ 2 then
        MinZoom(8)
    elseif minzoom <= 9 and area > ZRES8 ^ 2 then
        MinZoom(9)
    elseif minzoom <= 10 and area > ZRES9 ^ 2 then
        MinZoom(10)
    elseif minzoom <= 11 and area > ZRES10 ^ 2 then
        MinZoom(11)
    elseif minzoom <= 12 and area > ZRES11 ^ 2 then
        MinZoom(12)
    elseif minzoom <= 13 and area > ZRES12 ^ 2 then
        MinZoom(13)
    else
        MinZoom(14)
    end
end

-- Calculate POIs (typically rank 1-4 go to 'poi' z12-14, rank 5+ to 'poi_detail' z14)
-- returns rank, class, subclass
function GetPOIRank()
    local k, list, v, class, rank

    -- Can we find the tag?
    for k, list in pairs(poiTags) do
        if list[Find(k)] then
            v           = Find(k) -- k/v are the OSM tag pair
            class       = poiClasses[v] or k
            rank        = poiClassRanks[class] or 25
            subclassKey = poiSubClasses[v]
            if subclassKey then
                class = v
                v = Find(subclassKey)
            end
            return rank, class, v
        end
    end

    -- Catch-all for shops
    local shop = Find("shop")
    if shop ~= "" then return poiClassRanks['shop'], "shop", shop end

    -- Nothing found
    return nil, nil, nil
end

function SetBuildingHeightAttributes()
    local height = tonumber(Find("height"), 10)
    local minHeight = tonumber(Find("min_height"), 10)
    local levels = tonumber(Find("building:levels"), 10)
    local minLevel = tonumber(Find("building:min_level"), 10)

    local renderHeight = BUILDING_FLOOR_HEIGHT
    if height or levels then
        renderHeight = height or (levels * BUILDING_FLOOR_HEIGHT)
    end
    local renderMinHeight = 0
    if minHeight or minLevel then
        renderMinHeight = minHeight or (minLevel * BUILDING_FLOOR_HEIGHT)
    end

    -- Fix upside-down buildings
    if renderHeight < renderMinHeight then
        renderHeight = renderHeight + renderMinHeight
    end

    AttributeNumeric("render_height", renderHeight)
    AttributeNumeric("render_min_height", renderMinHeight)
end

-- Implement z_order as calculated by Imposm
-- See https://imposm.org/docs/imposm3/latest/mapping.html#wayzorder for details.
function SetZOrder()
    local highway = Find("highway")
    local layer = tonumber(Find("layer"))
    local bridge = Find("bridge")
    local tunnel = Find("tunnel")
    local zOrder = 0
    if bridge ~= "" and bridge ~= "no" then
        zOrder = zOrder + 10
    elseif tunnel ~= "" and tunnel ~= "no" then
        zOrder = zOrder - 10
    end
    if not (layer == nil) then
        if layer > 7 then
            layer = 7
        elseif layer < -7 then
            layer = -7
        end
        zOrder = zOrder + layer * 10
    end
    local hwClass = 0
    -- See https://github.com/omniscale/imposm3/blob/53bb80726ca9456e4a0857b38803f9ccfe8e33fd/mapping/columns.go#L251
    if highway == "motorway" then
        hwClass = 9
    elseif highway == "trunk" then
        hwClass = 8
    elseif highway == "primary" then
        hwClass = 6
    elseif highway == "secondary" then
        hwClass = 5
    elseif highway == "tertiary" then
        hwClass = 4
    else
        hwClass = 3
    end
    zOrder = zOrder + hwClass
    ZOrder(zOrder)
end

-- ==========================================================
-- Lua utility functions

function split(inputstr, sep) -- https://stackoverflow.com/a/7615129/4288232
    if sep == nil then
        sep = "%s"
    end
    local t = {}; i = 1
    for str in string.gmatch(inputstr, "([^" .. sep .. "]+)") do
        t[i] = str
        i = i + 1
    end
    return t
end

-- vim: tabstop=2 shiftwidth=2 noexpandtab
