-- LUALOCALS < ---------------------------------------------------------
local include, nodecore, pairs, string, table
= include, nodecore, pairs, string, table
local string_lower
= string.lower

-- LUALOCALS > ---------------------------------------------------------
local modname = minetest.get_current_modname()

--nodecore.gametime

local cache = {}

local global_search_maximum = 361

local directions = { [0] =
    vector.new(0, 0, -1),
    vector.new(-1, 0, 0),
    vector.new(0, 0, 1),
    vector.new(1, 0, 0),
}

local down = vector.new(0, -1, 0)

local solid_drawtypes = {
    normal = true,
    glasslike_framed = true,
}

--[[
E: air
E_: other empty
Etype: territory marker of some type
Stype: a go stone of some type
W: full block wall
WE0-WE3: edge concrete
WC0-WC3: corner concrete
WB: other goban concrete
--]]
local function _check_position_uncached(pos)
    local node = minetest.get_node(pos)

    if node.name == "air" then
        return "E"
    end

    local reg_item = minetest.registered_items[node.name]

    if not reg_item then
        return "W"
    end

    if reg_item.groups and reg_item.groups.go_stone then
        return "S" .. reg_item.go_team
    end

    if reg_item.groups and reg_item.groups.go_territory_marker then
        return "E" .. reg_item.go_team
    end

    if reg_item.pattern_def then
        if reg_item.pattern_def.name == "edgy" then
            return "WE" .. ((node.param2+2)%4)
        elseif reg_item.pattern_def.name == "corny" then
            return "WC" .. ((node.param2+2)%4)
        elseif reg_item.pattern_def.name == "crossy" then
            return "WB"
        elseif reg_item.pattern_def.name == "starcrossy" then
            return "WB"
        end
    end

    if solid_drawtypes[reg_item.drawtype] and not reg_item.groups.falling_node then
        return "W"
    else
        return "E_"
    end
end

local function check_position(pos)
    local hash = minetest.hash_node_position(pos)
    if cache[hash] then
        return cache[hash]
    end

    local ret = _check_position_uncached(pos)
    cache[hash] = ret
    return ret
end

local function set_and_cache(pos, value)
    nodecore.set_loud(pos, value)
    cache[minetest.hash_node_position(pos)] = _check_position_uncached(pos)
end

local smokecontrol
if nodecore.smokeclear then
    smokecontrol = function(pos, smoke)
        local existing = check_position(pos)


        if existing:sub(1, 1) == "S" then
            local node = minetest.get_node(pos)
            node.param2 = smoke
            minetest.swap_node(pos, node)

            if smoke then
                nodecore.smokefx(pos, 60, smoke)
            else
                nodecore.smokeclear(pos)
            end
        else
            if smoke then
                nodecore.smokefx(pos, smoke, 1)
            else
                nodecore.smokeclear(pos)
            end
        end



    end
else
    smokecontrol = function(pos, smoke) end
end

-- check for walls, physical or implied
local function edge_check(pos, dir, terminate)
    local under = check_position(pos + down)

    if under:sub(1, 1) == "W" and under:len() == 3 then
        local corner = (under:sub(2, 2) == "C")
        local edge_dir = tonumber(under:sub(3, 3))

        if (dir == edge_dir) or (corner and (dir == (edge_dir+1)%4)) then
            return true
        end
    end

    if not terminate then
        if edge_check(pos+directions[dir], (dir+2)%4, true) then
            return true
        end
    end

    return false
end

--[[
give valid neighbor directions from a position, excluding solid blocks
and also respecting borders indicated by goban concrete
--]]
local function neighbor_dirs(pos)
    local neighbors = {}
    for i,v in pairs(directions) do
        if not edge_check(pos, i) then
            if check_position(pos + directions[i]):sub(1, 1) ~= "W" then
                neighbors[#neighbors+1] = i
            end
        end
    end

    return neighbors
end

local function connected_search(pos, final_result, early_termination_filter)
    local group = {pos}
    local stones = {[minetest.hash_node_position(pos)] = pos}
    local checked = {}
    local piece = check_position(pos)

    local probe = 0
    while probe < #group do
        probe = probe + 1
        pos = group[probe]

        for i,v in pairs(neighbor_dirs(pos)) do
            local newpos = pos + directions[v]
            local newhash = minetest.hash_node_position(newpos)

            if (not stones[newhash]) and (not checked[newhash]) then
                local newnode = check_position(newpos)

                if newnode == piece then
                    stones[newhash] = newpos
                    group[#group+1] = newpos
                else
                    checked[newhash] = true
                end

                local filter_result
                if early_termination_filter then
                    filter_result = early_termination_filter(newnode, #group)
                end
                if filter_result then
                    filter_result.stones = stones
                    return filter_result
                end
            end
        end
    end

    final_result = final_result(#group)
    final_result.stones = stones
    return final_result
end

local function board_clear_fx(basepos)
    local group = {basepos}
    local checked = {[minetest.hash_node_position(basepos)] = basepos}

    local probe = 0
    while probe < #group do
        probe = probe + 1
        local pos = group[probe]

        for i,v in pairs(neighbor_dirs(pos)) do
            local newpos = pos + directions[v]

            if (math.abs(newpos.x - basepos.x) <= 18) and (math.abs(newpos.z - basepos.z) <= 18) then
                local newhash = minetest.hash_node_position(newpos)

                local groups = minetest.registered_nodes[minetest.get_node(newpos).name].groups
                if groups then
                    if groups.ko_stone then
                        set_and_cache(newpos, {name = "air"})
                    end
                    smokecontrol(newpos)
                end

                if (not checked[newhash]) then
                    group[#group+1] = newpos
                    checked[newhash] = true
                end
            end
        end
    end

end

local function _check_captures_filter(node, count)
    if (count > global_search_maximum) or (node:sub(1, 1) == "E") then
        return {capture = false}
    end
end

local function _check_captures_final(count)
    return {capture = count}
end

local function check_captures(pos)
    return connected_search(pos, _check_captures_final, _check_captures_filter)
end

local function _connected_group_final()
    return {complete = true}
end

local function _connected_group_filter(node, count)
    if (count > global_search_maximum) then
        return {}
    end
end

local function connected_group(pos)
    local search = connected_search(pos, _connected_group_final, _connected_group_filter)
    if search.complete then
        return search.stones
    else
        return {pos}
    end
end

local function territory_search(pos, max)
    if check_position(pos) ~= "E" then
        return {}
    end

    local team
    return connected_search(pos,
            function()
                return {team = team}
            end,
            function(node, count)
                if (count > max) then
                    return {}
                end

                if node ~= "E_" and ((node:sub(1, 1) == "E") or (node:sub(1, 1) == "S")) and node:len() > 1 then
                    node = node:sub(2, -1)
                    if team then
                        if team ~= node then
                            return {}
                        end
                    else
                        team = node
                    end
                end
            end
    )
end

local function multi_eject(proximal, stone, speed, count, inv)
    local stack_max = minetest.registered_items[stone].stack_max
    while count > 0 do
        local items = stone .. " " .. math.min(count, stack_max)
        if inv then items = inv:add_item("main", items) end
        nodecore.item_eject(proximal, items, speed)
        count = count - stack_max
    end
end

local firenode = "nc_fire:fire_burst"
if not minetest.registered_nodes["nc_fire:fire_burst"] then
    firenode = "nc_fire:fire"
end

function lc_liberties.handle_placement(pos)
    cache = {}
    --minetest.chat_send_all(tostring(pos))

    local our_stone = check_position(pos)
    if our_stone:sub(1, 1) ~= "S" then
        return
    end
    our_stone = our_stone:sub(2, -1)

    local captureses = {}
    local captured = false
    for i,v in pairs(neighbor_dirs(pos)) do
        local new_pos = pos + directions[v]

        local hash = minetest.hash_node_position(new_pos)

        local checked = false
        for i2,v2 in pairs(captureses) do
            if v2.stones[hash] then
                checked = true
            end
        end

        if not checked then
            local node = check_position(new_pos)
            if (node:sub(1, 1) == "S") and (node:sub(2, -1) ~= our_stone) then
                local captures = check_captures(new_pos)
                if captures.capture then
                    captured = (captured or 0) + captures.capture
                end

                captureses[#captureses+1] = captures
            end
        end
    end

    local allcaptured = {}
    local ko
    if captured then
        if captured == 1 then
            for i,v in pairs(neighbor_dirs(pos)) do
                local new_stone = check_position(pos + directions[v])
                if (new_stone:sub(2, -1) == our_stone) or (new_stone:sub(1, 1) == "E") then
                    goto noko
                end
            end

            ko = true

            ::noko::
        end

        for i,v in pairs(captureses) do
            if v.capture then
                local stone = check_position(v.stones[next(v.stones)]):sub(2, -1) -- minetest.get_node().name)
                local count = 0

                local proximal
                local proximal_c = 0

                for i2, v2 in pairs(v.stones) do
                    allcaptured[#allcaptured + 1] = v2

                    if ko then
                        -- save ko capture position, for adding ko marker in fx phase
                        ko = {stone = stone, pos = v2}
                    end

                    local under = check_position(v2 + down)
                    if (under:sub(1, 1) == "W") and (under:len() > 1) then
                        nodecore.sound_play("nc_fire_ignite", {gain = 1, pos = pos})
                        set_and_cache(v2, {name = firenode})
                    else
                        set_and_cache(v2, {name = "air"})
                    end

                    count = count + 1
                    if (v2:distance(pos) < 2.3) then
                        proximal_c = proximal_c + 1
                        if math.random(1, proximal_c) == 1 then
                            proximal = v2
                        end
                    end
                end

                multi_eject(proximal, modname .. ":stone_" .. stone, 3, count)
            end
        end
    else
        -- if no capture was made, check for a self-capture and reject the move
        local captures = check_captures(pos)
        if captures.capture then
            local stone = minetest.get_node(pos).name
            set_and_cache(pos, {name = "air"})
            nodecore.item_eject(pos, stone, 5)

            return
        end
    end

    board_clear_fx(pos)

    smokecontrol(pos, 2+#allcaptured)

    for i = #allcaptured, 1, -1 do
        local chosen = math.random(1, i)
        smokecontrol(allcaptured[chosen], 90)
        allcaptured[chosen] = allcaptured[i]
    end

    if ko then
        set_and_cache(ko.pos, {name = modname .. ":ko_" .. ko.stone})
    end
end

function lc_liberties.handle_territory_fill(itemstack, placer, pointed_thing)
    local control = placer.get_player_control and placer:get_player_control()

    if (control and (control.aux1 or control.sneak)) then
        local ret = minetest.item_place(itemstack, placer, pointed_thing)
        if (pointed_thing and pointed_thing.under) then
            nodecore.node_sound(pointed_thing.under, "place")
        end
        return ret
    end

    local under
    if (pointed_thing and pointed_thing.under) then
        under = minetest.get_node(pointed_thing.under)
        local override_rightclick = minetest.registered_nodes[under.name].on_rightclick
        if override_rightclick then
            return override_rightclick(pointed_thing.under, under, placer, itemstack, pointed_thing)
        end
    end

    if pointed_thing and pointed_thing.above then
        if under then
            local reg_item = minetest.registered_items[under.name]

            if reg_item and reg_item.groups and reg_item.groups.go_stone then
                set_and_cache(pointed_thing.above, {name = modname .. ":territory_" .. reg_item.go_team})
                itemstack:set_count(itemstack:get_count() - 1)
                return itemstack
            end
        end

        cache = {}
        local territories = territory_search(pointed_thing.above, itemstack:get_count())
        if territories.team then
            local piece = modname .. ":territory_" .. territories.team
            local count = 0
            for i, v in pairs(territories.stones) do
                set_and_cache(v, {name = piece})
                count = count + 1
            end
            itemstack:set_count(itemstack:get_count() - count)
        end
    end

    return itemstack
end

function lc_liberties.handle_dig(pos, node, digger)
    local control = digger.get_player_control and digger:get_player_control()
    if (control and (control.aux1 or control.sneak))
                ~=
            (minetest.registered_items[node.name].groups.go_territory_marker ~= nil)
                then
        cache = {}

        local stone = minetest.get_node(pos).name

        local count = 0
        for i, v in pairs(connected_group(pos)) do
            count = count + 1
            set_and_cache(v, {name = "air"})
        end

        multi_eject(pos, stone, 1, count, digger and digger:get_inventory())

        return true
    else
        return minetest.node_dig(pos, node, digger)
    end
end

function lc_liberties.handle_click_ko(pos, node, clicker, itemstack, pointed_thing)
    local handnode = minetest.registered_nodes[itemstack:get_name()]
    if handnode and handnode.groups.go_stone and
            handnode.go_team ~= minetest.registered_nodes[node.name].go_team then
        set_and_cache(pos, {name = handnode.name})
        itemstack:set_count(itemstack:get_count() - 1)
    end
    return itemstack
end