local Task = require "utils.Task"
local Token = require "utils.global_token"

local shape
local place_decoratives = true

local function do_row(row, data)
    local function do_tile(tile, pos)
        if not tile then
            table.insert(data.tiles, {name = "out-of-map", position = pos})
        elseif type(tile) == "string" then
            table.insert(data.tiles, {name = tile, position = pos})
        end
    end

    local y = data.top_y + row
    local top_x = data.top_x

    data.y = y

    for x = top_x, top_x + 31 do
        data.x = x
        local pos = {data.x, data.y}

        -- local coords need to be 'centered' to allow for correct rotation and scaling.
        local tile = shape(x + 0.5, y + 0.5, data)

        if type(tile) == "table" then            
            do_tile(tile.tile, pos)

            local entities = tile.entities
            if entities then
                for _, entity in ipairs(entities) do
                    if not entity.position then
                        entity.position = pos
                    end
                    table.insert(data.entities, entity)
                end
            end

            --[[ local decoratives = tile.decoratives
            if decoratives then
                for _, decorative in ipairs(decoratives) do
                    table.insert(data.decoratives, decorative)
                end
            end ]]
        else
            do_tile(tile, pos)
        end
    end
end

local function do_place_tiles(data)
    data.surface.set_tiles(data.tiles, true)
end

local decoratives = {
    "brown-asterisk",
    "brown-carpet-grass",
    "brown-fluff",
    "brown-fluff-dry",
    "brown-hairy-grass",
    "garballo",
    "garballo-mini-dry",
    "green-asterisk",
    "green-bush-mini",
    "green-carpet-grass",
    "green-hairy-grass",
    "green-pita",
    "green-pita-mini",
    "green-small-grass",
    "red-asterisk"
}

local function do_place_decoratives(data)
    if not place_decoratives then
        return
    end

    data.surface.regenerate_decorative(decoratives, {{data.top_x / 32, data.top_y / 32}})
end

local function do_place_entities(data)
    local surface = data.surface
    for _, e in ipairs(data.entities) do
        if surface.can_place_entity(e) then
            local entity = surface.create_entity(e)
            if e.callback then
                local callback = Token.get(e.callback)
                callback(entity)
            end
        end
    end
end

local function run_chart_update(data)
    local x = data.top_x / 32
    local y = data.top_y / 32
    if game.forces.player.is_chunk_charted(data.surface, {x, y}) then
        -- Don't use full area, otherwise adjacent chunks get charted
        game.forces.player.chart(
            data.surface,
            {
                {data.top_x, data.top_y},
                {data.top_x + 1, data.top_y + 1}
            }
        )
    end
end

function map_gen_action(data)
    local state = data.state
    if state < 32 then
        do_row(state, data)
        data.state = state + 1
        return true
    elseif state == 32 then
        do_place_tiles(data)
        data.state = 33
        return true
    elseif state == 33 then
        do_place_entities(data)
        data.state = 34
        return true
    elseif state == 34 then
        do_place_decoratives(data)
        data.state = 35
        return true
    elseif state == 35 then
        run_chart_update(data)
        return false
    end
end

local function on_chunk(event)
    local area = event.area

    local data = {
        state = 0,
        top_x = area.left_top.x,
        top_y = area.left_top.y,
        surface = event.surface,
        tiles = {},
        entities = {},
        decoratives = {}
    }
    Task.queue_task("map_gen_action", data, 36)
end

local function init(s)
    shape = s
    return on_chunk
end

return init