local H = wesnoth.require "lua/helper.lua"
local AH = wesnoth.require "ai/lua/ai_helper.lua"

local function get_tusklets(cfg)
    local tusklets = AH.get_units_with_moves {
        side = wesnoth.current.side,
        type = cfg.tusklet_type
    }
    return tusklets
end

local function get_tuskers(cfg)
    local tuskers = wesnoth.get_units {
        side = wesnoth.current.side,
        type = cfg.tusker_type
    }
    return tuskers
end

local ca_forest_animals_tusklet_move = {}

function ca_forest_animals_tusklet_move:evaluation(ai, cfg)
    -- Tusklets will simply move toward the closest tusker, without regard for anything else
    -- Except if no tuskers are left, in which case ca_forest_animals_move takes over and does a random move

    if (not cfg.tusker_type) or (not cfg.tusklet_type) then return 0 end
    if (not get_tusklets(cfg)[1]) then return 0 end
    if (not get_tuskers(cfg)[1]) then return 0 end
    return cfg.ca_score
end

function ca_forest_animals_tusklet_move:execution(ai, cfg)
    local tusklets = get_tusklets(cfg)
    local tuskers = get_tuskers(cfg)

    for _,tusklet in ipairs(tusklets) do
        local goto_tusker, min_dist = {}, 9e99
        for _,tusker in ipairs(tuskers) do
            local dist = H.distance_between(tusker.x, tusker.y, tusklet.x, tusklet.y)
            if (dist < min_dist) then
                min_dist, goto_tusker = dist, tusker
            end
        end

        local best_hex = AH.find_best_move(tusklet, function(x, y)
            return - H.distance_between(x, y, goto_tusker.x, goto_tusker.y)
        end)

        AH.movefull_stopunit(ai, tusklet, best_hex)

        -- Also make sure tusklets never attack
        if tusklet and tusklet.valid then AH.checked_stopunit_all(ai, tusklet) end
    end
end

return ca_forest_animals_tusklet_move