42.20 and Towtrucks

42.20/media/lua/shared/TowBar/Persistence.lua

@@ -0,0 +1,122 @@
+if not TowBarMod then TowBarMod = {} end
+TowBarMod.Persistence = TowBarMod.Persistence or {}
+
+local Persistence = TowBarMod.Persistence
+local RegistryName = "TowBar.PersistentPairsV2"
+
+local function getRegistry()
+    if not ModData or not ModData.getOrCreate then return nil end
+    local registry = ModData.getOrCreate(RegistryName)
+    registry.pairs = registry.pairs or {}
+    return registry
+end
+
+local function getSqlId(vehicle)
+    if not vehicle or not vehicle.getSqlId then return nil end
+    local ok, sqlId = pcall(function() return vehicle:getSqlId() end)
+    if ok and type(sqlId) == "number" and sqlId >= 0 then return sqlId end
+    return nil
+end
+
+local function makeKey(kind, towingSqlId, towedSqlId)
+    if type(kind) ~= "string" or type(towingSqlId) ~= "number" or type(towedSqlId) ~= "number" then
+        return nil
+    end
+    return kind .. ":" .. tostring(towingSqlId) .. ":" .. tostring(towedSqlId)
+end
+
+local function transmit()
+    if isServer and isServer() and ModData.transmit then
+        ModData.transmit(RegistryName)
+    end
+end
+
+function Persistence.savePair(kind, towingVehicle, towedVehicle, attachmentA, attachmentB, heightLevel)
+    local towingSqlId = getSqlId(towingVehicle)
+    local towedSqlId = getSqlId(towedVehicle)
+    local key = makeKey(kind, towingSqlId, towedSqlId)
+    local registry = getRegistry()
+    if not key or not registry then return false end
+    local previous = registry.pairs[key]
+    if previous and previous.attachmentA == attachmentA and previous.attachmentB == attachmentB
+            and previous.heightLevel == heightLevel then
+        return true
+    end
+    registry.pairs[key] = {
+        kind = kind,
+        towingSqlId = towingSqlId,
+        towedSqlId = towedSqlId,
+        attachmentA = attachmentA,
+        attachmentB = attachmentB,
+        heightLevel = heightLevel
+    }
+    transmit()
+    return true
+end
+
+function Persistence.getPair(kind, towingVehicle, towedVehicle)
+    local key = makeKey(kind, getSqlId(towingVehicle), getSqlId(towedVehicle))
+    local registry = getRegistry()
+    return key and registry and registry.pairs[key] or nil
+end
+
+function Persistence.removePair(kind, towingVehicle, towedVehicle)
+    local key = makeKey(kind, getSqlId(towingVehicle), getSqlId(towedVehicle))
+    local registry = getRegistry()
+    if not key or not registry or registry.pairs[key] == nil then return false end
+    registry.pairs[key] = nil
+    transmit()
+    return true
+end
+
+function Persistence.forEachPair(kind, callback)
+    local registry = getRegistry()
+    if not registry or not callback then return end
+    for _, record in pairs(registry.pairs) do
+        if type(record) == "table" and record.kind == kind then callback(record) end
+    end
+end
+
+function Persistence.notePeerAvailability(state, available)
+    state = state or {}
+    if not available then
+        state.peerMissing = true
+        return state
+    end
+    if state.peerMissing then
+        -- A missing vehicle means its cell was not loaded. When both members
+        -- return, treat the absent native constraint as load recovery rather
+        -- than a runtime break of a previously confirmed pair.
+        state.peerMissing = nil
+        state.confirmed = false
+        state.pendingUntil = nil
+        state.unlinkedSince = nil
+    end
+    return state
+end
+
+function Persistence.advanceRecoveryState(state, now, linked, occupied, retryMs, breakMs)
+    state = state or {}
+    if linked then
+        state.confirmed = true
+        state.pendingUntil = nil
+        state.unlinkedSince = nil
+        return state, "adopt"
+    end
+    if occupied then
+        state.unlinkedSince = nil
+        return state, "wait"
+    end
+    if state.confirmed then
+        state.unlinkedSince = state.unlinkedSince or now
+        if now - state.unlinkedSince >= breakMs then return state, "break" end
+        return state, "wait"
+    end
+    if not state.pendingUntil or now >= state.pendingUntil then
+        state.pendingUntil = now + retryMs
+        return state, "restore"
+    end
+    return state, "wait"
+end
+
+Persistence.getSqlId = getSqlId