local shared = require 'config.shared'

--- Zeitpunkt des letzten akzeptierten Syncs pro Spieler. Basis für die
--- Plausibilitätsprüfung: mehr als maxDrainPerSecond pro echter Sekunde kann
--- niemand verbrauchen.
local lastSync = {}

--- @param source number
--- @param slotId number
--- @return table? slot, table? tankConfig
local function getTankSlot(source, slotId)
    if type(slotId) ~= 'number' then return end

    local slot = exports.ox_inventory:GetSlot(source, slotId)

    if not slot then return end

    local tankConfig = shared.tankByName[slot.name]

    if not tankConfig then return end

    return slot, tankConfig
end

--- Schreibt die Restluft in die Metadata.
--- SetMetadata *ersetzt* die Metadata-Tabelle komplett (modules/inventory/server.lua),
--- deshalb wird der bestehende Inhalt kopiert statt nur oxygen gesetzt.
--- @return number oxygen akzeptierte Restsekunden
local function writeTank(source, slot, tankConfig, oxygen)
    oxygen = math.floor(math.max(0, math.min(oxygen, tankConfig.capacity)))

    local metadata = {}

    for key, value in pairs(slot.metadata or {}) do
        metadata[key] = value
    end

    metadata.oxygen = oxygen
    -- durability zeigt den Füllstand direkt im Inventar-Slot an. Kein decay auf den
    -- Items, sonst würde ox_inventory die leere Flasche löschen (items/server.lua).
    metadata.durability = math.floor(oxygen / tankConfig.capacity * 100)

    exports.ox_inventory:SetMetadata(source, slot.slot, metadata)

    return oxygen
end

--- Alle Tauchflaschen im Inventar mit Füllstand.
--- @param source number
--- @return table[]
local function getTankList(source)
    local found = exports.ox_inventory:Search(source, 'slots', shared.tankNames)
    local tanks = {}

    for i = 1, #shared.tankNames do
        local name = shared.tankNames[i]
        local slots = found and found[name]
        local tankConfig = shared.tankByName[name]

        if slots then
            for j = 1, #slots do
                local slot = slots[j]
                local oxygen = tonumber(slot.metadata and slot.metadata.oxygen) or 0

                tanks[#tanks + 1] = {
                    slot = slot.slot,
                    name = name,
                    label = (exports.ox_inventory:Items(name) or {}).label or name,
                    oxygen = math.max(0, math.min(oxygen, tankConfig.capacity)),
                    capacity = tankConfig.capacity
                }
            end
        end
    end

    return tanks
end

--- @return number? accepted
local function syncTank(source, slotId, oxygen)
    oxygen = tonumber(oxygen)

    if not oxygen then return end

    local slot, tankConfig = getTankSlot(source, slotId)

    if not slot then return end

    local current = tonumber(slot.metadata and slot.metadata.oxygen) or tankConfig.capacity
    local now = os.time()
    local elapsed = lastSync[source] and (now - lastSync[source]) or shared.syncIntervalSeconds

    lastSync[source] = now

    -- Luft kann nur weniger werden, und nicht schneller als physikalisch möglich.
    local floorValue = math.max(0, current - math.max(1, elapsed) * shared.maxDrainPerSecond)
    local accepted = math.max(floorValue, math.min(oxygen, current))

    return writeTank(source, slot, tankConfig, accepted)
end

lib.callback.register('d4rk_divegear:server:getTanks', getTankList)

lib.callback.register('d4rk_divegear:server:syncTank', function(source, slotId, oxygen)
    return syncTank(source, slotId, oxygen)
end)

--- Fire-and-Forget-Variante für Tod und Resource-Stop, wo auf keine Antwort
--- mehr gewartet werden kann.
RegisterNetEvent('d4rk_divegear:server:syncTankNow', function(slotId, oxygen)
    syncTank(source, slotId, oxygen)
end)

AddEventHandler('playerDropped', function()
    lastSync[source] = nil
end)

exports.qbx_core:CreateUseableItem('diving_gear', function(source)
    TriggerClientEvent('d4rk_divegear:client:useGear', source)
end)

exports.qbx_core:CreateUseableItem('diving_fill', function(source)
    local tanks = getTankList(source)

    if #tanks == 0 then
        exports.qbx_core:Notify(source, locale('error.no_tank'), 'error')
        return
    end

    local slotId = lib.callback.await('d4rk_divegear:client:fillTank', source, tanks)

    if not slotId then return end

    local slot, tankConfig = getTankSlot(source, slotId)

    if not slot then return end

    -- Nach dem Progressbar nochmal prüfen: das Item kann in der Zwischenzeit weg sein.
    if not exports.ox_inventory:RemoveItem(source, 'diving_fill', 1) then return end

    writeTank(source, slot, tankConfig, tankConfig.capacity)
    lastSync[source] = os.time()

    -- Erst melden wenn das Item tatsächlich weg und die Flasche voll ist.
    exports.qbx_core:Notify(source, locale('success.tube_filled'), 'success')
    TriggerClientEvent('d4rk_divegear:client:tankRefilled', source, slot.slot, tankConfig.capacity)
end)