local Event = require 'utils.event'
local Task = require 'utils.Task'
local Token = require 'utils.global_token'

local function on_init()
    global.corpse_util_corpses = {}
end

local function player_died(event)
    local player = game.players[event.player_index]

    if not player or not player.valid then
        return
    end

    local pos = player.position
    local entities =
        player.surface.find_entities_filtered {
        area = {{pos.x, pos.y}, {pos.x + 1, pos.y + 1}},
        name = 'character-corpse'
    }
    local entity
    for _, e in ipairs(entities) do
        if e.character_corpse_player_index == event.player_index then
            entity = e
            break
        end
    end

    if not entity or not entity.valid then
        return
    end

    local text = player.name .. "'s corpse"
    local position = entity.position
    local tag =
        player.force.add_chart_tag(
        player.surface,
        {icon = {type = 'item', name = 'power-armor-mk2'}, position = position, text = text}
    )

    if not tag then
        return
    end

    global.corpse_util_corpses[position.x .. ',' .. position.y] = tag
end

local function remove_tag(position)
    local pos = position.x .. ',' .. position.y

    local tag = global.corpse_util_corpses[pos]
    if tag then
        global.corpse_util_corpses[pos] = nil
    end

    if not tag or not tag.valid then
        return
    end

    tag.destroy()
end

local function corpse_expired(event)
    local entity = event.corpse

    if entity and entity.valid then
        remove_tag(entity.position)
    end
end

local corpse_util_mined_entity =
    Token.register(
    function(data)
        if not data.entity.valid then
            remove_tag(data.position)
        end
    end
)

local function mined_entity(event)
    local entity = event.entity

    if entity and entity.valid and entity.name == 'character-corpse' then
        -- The corpse may be mined but not removed (if player doesn't have inventory space)
        -- so we wait one tick to see if the corpse is gone.
        Task.set_timeout_in_ticks(1, corpse_util_mined_entity, {entity = entity, position = entity.position})
    end
end

Event.on_init(on_init)
Event.add(defines.events.on_player_died, player_died)
Event.add(defines.events.on_character_corpse_expired, corpse_expired)
Event.add(defines.events.on_pre_player_mined_item, mined_entity)