local WD = require 'modules.wave_defense.table'
local threat_values = require 'modules.wave_defense.threat_values'
local Event = require 'utils.event'
local BiterRolls = require 'modules.wave_defense.biter_rolls'
local BiterHealthBooster = require 'modules.biter_health_booster_v2'
local math_random = math.random

local Public = {}

local function remove_unit(entity)
    local active_biters = WD.get('active_biters')
    local unit_number = entity.unit_number
    if not active_biters[unit_number] then
        return
    end
    local m = 1
    local biter_health_boost_units = BiterHealthBooster.get('biter_health_boost_units')
    if biter_health_boost_units[unit_number] then
        m = 1 / biter_health_boost_units[unit_number][2]
    end
    local active_threat_loss = math.round(threat_values[entity.name] * m, 2)
    local active_biter_threat = WD.get('active_biter_threat')
    WD.set('active_biter_threat', active_biter_threat - active_threat_loss)
    local active_biter_count = WD.get('active_biter_count')
    WD.set('active_biter_count', active_biter_count - 1)
    active_biters[unit_number] = nil
end

local function place_nest_near_unit_group()
    local unit_groups = WD.get('unit_groups')
    local random_group = WD.get('random_group')
    local group = unit_groups[random_group]
    if not group then
        return
    end
    if not group.valid then
        return
    end
    if not group.members then
        return
    end
    if not group.members[1] then
        return
    end
    local unit = group.members[math_random(1, #group.members)]
    if not unit.valid then
        return
    end
    local name = 'biter-spawner'
    if math_random(1, 3) == 1 then
        name = 'spitter-spawner'
    end
    local position = unit.surface.find_non_colliding_position(name, unit.position, 12, 1)
    if not position then
        return
    end
    local r = WD.get('nest_building_density')
    if
        unit.surface.count_entities_filtered(
            {
                type = 'unit-spawner',
                force = unit.force,
                area = {{position.x - r, position.y - r}, {position.x + r, position.y + r}}
            }
        ) > 0
     then
        return
    end
    local spawner = unit.surface.create_entity({name = name, position = position, force = unit.force})
    local nests = WD.get('nests')
    nests[#nests + 1] = spawner
    unit.surface.create_entity({name = 'blood-explosion-huge', position = position})
    unit.surface.create_entity({name = 'blood-explosion-huge', position = unit.position})
    remove_unit(unit)
    unit.destroy()
    local threat = WD.get('threat')
    WD.set('threat', threat - threat_values[name])
    return true
end

function Public.build_nest()
    local threat = WD.get('threat')
    if threat < 1024 then
        return
    end
    local index = WD.get('index')
    if index == 0 then
        return
    end
    for _ = 1, 2, 1 do
        if place_nest_near_unit_group() then
            return
        end
    end
end

function Public.build_worm()
    local threat = WD.get('threat')
    if threat < 512 then
        return
    end
    local worm_building_chance = WD.get('worm_building_chance')
    if math_random(1, worm_building_chance) ~= 1 then
        return
    end

    local index = WD.get('index')
    if index == 0 then
        return
    end

    local random_group = WD.get('random_group')
    local unit_groups = WD.get('unit_groups')
    local group = unit_groups[random_group]
    if not group then
        return
    end
    if not group.valid then
        return
    end
    if not group.members then
        return
    end
    if not group.members[1] then
        return
    end
    local unit = group.members[math_random(1, #group.members)]
    if not unit.valid then
        return
    end

    local wave_number = WD.get('wave_number')
    local position = unit.surface.find_non_colliding_position('assembling-machine-1', unit.position, 8, 1)
    BiterRolls.wave_defense_set_worm_raffle(wave_number)
    local worm = BiterRolls.wave_defense_roll_worm_name()
    if not position then
        return
    end

    local worm_building_density = WD.get('worm_building_density')
    local r = worm_building_density
    if
        unit.surface.count_entities_filtered(
            {
                type = 'turret',
                force = unit.force,
                area = {{position.x - r, position.y - r}, {position.x + r, position.y + r}}
            }
        ) > 0
     then
        return
    end
    unit.surface.create_entity({name = worm, position = position, force = unit.force})
    unit.surface.create_entity({name = 'blood-explosion-huge', position = position})
    unit.surface.create_entity({name = 'blood-explosion-huge', position = unit.position})
    remove_unit(unit)
    unit.destroy()
    WD.set('threat', threat - threat_values[worm])
end

local function shred_simple_entities(entity)
    local threat = WD.get('threat')
    if threat < 25000 then
        return
    end
    local simple_entities =
        entity.surface.find_entities_filtered(
        {
            type = 'simple-entity',
            area = {{entity.position.x - 3, entity.position.y - 3}, {entity.position.x + 3, entity.position.y + 3}}
        }
    )
    if #simple_entities == 0 then
        return
    end
    if #simple_entities > 1 then
        table.shuffle_table(simple_entities)
    end
    local r = math.floor(threat * 0.00004)
    if r < 1 then
        r = 1
    end
    local count = math.random(1, r)
    --local count = 1
    local damage_dealt = 0
    for i = 1, count, 1 do
        if not simple_entities[i] then
            break
        end
        if simple_entities[i].valid then
            if simple_entities[i].health then
                damage_dealt = damage_dealt + simple_entities[i].health
                simple_entities[i].die('neutral', simple_entities[i])
            end
        end
    end
    if damage_dealt == 0 then
        return
    end
    local simple_entity_shredding_cost_modifier = WD.get('simple_entity_shredding_cost_modifier')
    local threat_cost = math.floor(damage_dealt * simple_entity_shredding_cost_modifier)
    if threat_cost < 1 then
        threat_cost = 1
    end
    WD.set('threat', threat - threat_cost)
end

local function spawn_unit_spawner_inhabitants(entity)
    if entity.type ~= 'unit-spawner' then
        return
    end
    local wave_number = WD.get('wave_number')
    local count = 8 + math.floor(wave_number * 0.02)
    if count > 128 then
        count = 128
    end
    BiterRolls.wave_defense_set_unit_raffle(wave_number)
    for _ = 1, count, 1 do
        local position = {entity.position.x + (-4 + math.random(0, 8)), entity.position.y + (-4 + math.random(0, 8))}
        if math.random(1, 4) == 1 then
            entity.surface.create_entity({name = BiterRolls.wave_defense_roll_spitter_name(), position = position, force = 'enemy'})
        else
            entity.surface.create_entity({name = BiterRolls.wave_defense_roll_biter_name(), position = position, force = 'enemy'})
        end
    end
end

local function on_entity_died(event)
    local entity = event.entity
    if not entity.valid then
        return
    end

    local disable_threat_below_zero = WD.get('disable_threat_below_zero')
    local biter_health_boost = BiterHealthBooster.get('biter_health_boost')

    if entity.type == 'unit' then
        --acid_nova(entity)
        if not threat_values[entity.name] then
            return
        end
        if disable_threat_below_zero then
            local threat = WD.get('threat')
            if threat <= 0 then
                WD.set('threat', 0)
                threat = WD.get('threat')
            end
            WD.set('threat', math.round(threat - threat_values[entity.name] * biter_health_boost, 2))
            remove_unit(entity)
        else
            local threat = WD.get('threat')
            WD.set('threat', math.round(threat - threat_values[entity.name] * biter_health_boost, 2))
            remove_unit(entity)
        end
    else
        if entity.force.index == 2 then
            if entity.health then
                if threat_values[entity.name] then
                    local threat = WD.get('threat')
                    WD.set('threat', math.round(threat - threat_values[entity.name] * biter_health_boost, 2))
                end
                spawn_unit_spawner_inhabitants(entity)
            end
        end
    end

    if entity.force.index == 3 then
        if event.cause then
            if event.cause.valid then
                if event.cause.force.index == 2 then
                    shred_simple_entities(entity)
                end
            end
        end
    end
end

Event.add(defines.events.on_entity_died, on_entity_died)

return Public