diff --git a/FS25_ADSmartPickup/adFieldModel.lua b/FS25_ADSmartPickup/adFieldModel.lua
new file mode 100644
index 0000000..1afdeb7
--- /dev/null
+++ b/FS25_ADSmartPickup/adFieldModel.lua
@@ -0,0 +1,163 @@
+-- AD Field Model
+-- Markarbejdets regler som ren data (ingen spil-API): en marks plan og trin, hvornår den er klar,
+-- hvilket trin der følger, hvor mange sæt et trin må have, og bredde-reglerne. Alle funktioner
+-- returnerer nye tabeller; job-løkken (adFieldJobs) og GUI'et kalder kun herind.
+
+ADFieldModel = {}
+
+ADFieldModel.READY_RATIO = 0.9
+ADFieldModel.CUT_RATIO = 0.5
+ADFieldModel.CP_MAX_WIDTH = 50
+ADFieldModel.WIDTH_TOLERANCE = 0.05
+ADFieldModel.RETRY_MS = 300000
+ADFieldModel.MAX_COLLECTORS = 2
+
+ADFieldModel.ROLES = {mowing = "mower", tedding = "tedder", raking = "rake", collecting = "collector"}
+local KNOWN_STAGES = {idle = true, ready = true, mowing = true, tedding = true, raking = true, collecting = true, done = true}
+
+local function copyList(list)
+    local copy = {}
+    for index, value in ipairs(list or {}) do copy[index] = value end
+    return copy
+end
+
+local function copyField(field)
+    local copy = {}
+    for key, value in pairs(field) do copy[key] = value end
+    copy.plan = {
+        mode = field.plan.mode, product = field.plan.product, rake = field.plan.rake,
+        storeBuildingIds = copyList(field.plan.storeBuildingIds),
+    }
+    return copy
+end
+
+function ADFieldModel.newField(id)
+    return {
+        id = id, stage = "idle", mowWidth = nil, retryAt = 0, reason = nil, startRequested = false,
+        plan = {mode = "manual", product = "silage", rake = false, storeBuildingIds = {}},
+    }
+end
+
+function ADFieldModel.workStages(plan)
+    if plan.product == "hay" then
+        if plan.rake then
+            return {"mowing", "tedding", "raking", "collecting"}
+        end
+        return {"mowing", "tedding", "collecting"}
+    end
+    return {"mowing", "collecting"}
+end
+
+function ADFieldModel.roleFor(stage)
+    return ADFieldModel.ROLES[stage]
+end
+
+function ADFieldModel.isWorking(field)
+    return ADFieldModel.ROLES[field.stage] ~= nil
+end
+
+function ADFieldModel.maxRigs(stage)
+    return stage == "collecting" and ADFieldModel.MAX_COLLECTORS or 1
+end
+
+-- Venter/færdig -> klar ved fuld vækst; klar -> venter hvis marken blev slået uden os.
+-- Arbejdende marker styres af job-løkken, ikke af vækst.
+function ADFieldModel.onReadiness(field, ratio)
+    local copy = copyField(field)
+    if (field.stage == "idle" or field.stage == "done") and ratio >= ADFieldModel.READY_RATIO then
+        copy.stage = "ready"
+    elseif field.stage == "ready" and ratio < ADFieldModel.CUT_RATIO then
+        copy.stage = "idle"
+        copy.startRequested = false
+    end
+    return copy
+end
+
+function ADFieldModel.shouldStart(field)
+    return field.stage == "ready" and (field.plan.mode == "auto" or field.startRequested == true)
+end
+
+function ADFieldModel.start(field)
+    local copy = copyField(field)
+    copy.stage = ADFieldModel.workStages(field.plan)[1]
+    copy.startRequested = false
+    copy.retryAt = 0
+    copy.reason = nil
+    copy.mowWidth = nil
+    return copy
+end
+
+function ADFieldModel.advance(field)
+    local copy = copyField(field)
+    local stages = ADFieldModel.workStages(field.plan)
+    copy.stage = "done"
+    for index, stage in ipairs(stages) do
+        if stage == field.stage and stages[index + 1] ~= nil then
+            copy.stage = stages[index + 1]
+        end
+    end
+    copy.retryAt = 0
+    copy.reason = nil
+    return copy
+end
+
+-- Stop fra menuen: arbejdet afbrydes; marken står klar igen (manuel start kræves).
+function ADFieldModel.stop(field)
+    local copy = copyField(field)
+    if ADFieldModel.isWorking(field) then
+        copy.stage = "ready"
+    end
+    copy.startRequested = false
+    copy.reason = nil
+    return copy
+end
+
+-- Et sæt må ikke over Courseplays grænse; efter-trin skal dække mindst slåbredden.
+function ADFieldModel.checkWidth(role, width, mowWidth)
+    if width > ADFieldModel.CP_MAX_WIDTH + ADFieldModel.WIDTH_TOLERANCE then
+        return false, "tooWide", {width, ADFieldModel.CP_MAX_WIDTH}
+    end
+    if role ~= "mower" and mowWidth ~= nil and width + ADFieldModel.WIDTH_TOLERANCE < mowWidth then
+        return false, "tooNarrow", {width, mowWidth}
+    end
+    return true
+end
+
+function ADFieldModel.wantsRig(field, assignedCount, now)
+    local role = ADFieldModel.roleFor(field.stage)
+    if role == nil or (field.retryAt or 0) > now or assignedCount >= ADFieldModel.maxRigs(field.stage) then
+        return nil
+    end
+    return role
+end
+
+function ADFieldModel.with(field, changes)
+    local copy = copyField(field)
+    for key, value in pairs(changes) do
+        if key == "plan" then
+            for planKey, planValue in pairs(value) do copy.plan[planKey] = planValue end
+        else
+            copy[key] = value
+        end
+    end
+    return copy
+end
+
+function ADFieldModel.toRecord(field)
+    return {
+        id = field.id, stage = field.stage, mode = field.plan.mode, product = field.plan.product,
+        rake = field.plan.rake and 1 or 0, store = table.concat(field.plan.storeBuildingIds, " "),
+        mowWidth = field.mowWidth or 0,
+    }
+end
+
+function ADFieldModel.fromRecord(record)
+    local field = ADFieldModel.newField(record.id)
+    field.stage = KNOWN_STAGES[record.stage] and record.stage or "idle"
+    field.plan.mode = record.mode == "auto" and "auto" or "manual"
+    field.plan.product = record.product == "hay" and "hay" or "silage"
+    field.plan.rake = record.rake == 1 or record.rake == true
+    for id in string.gmatch(record.store or "", "%S+") do table.insert(field.plan.storeBuildingIds, id) end
+    field.mowWidth = (record.mowWidth or 0) > 0 and record.mowWidth or nil
+    return field
+end
diff --git a/tests/test_adFieldModel.lua b/tests/test_adFieldModel.lua
new file mode 100644
index 0000000..2737a70
--- /dev/null
+++ b/tests/test_adFieldModel.lua
@@ -0,0 +1,99 @@
+-- Kør: luajit tests/test_adFieldModel.lua   (fra repo-roden)
+dofile("FS25_ADSmartPickup/adFieldModel.lua")
+local M = ADFieldModel
+local failures = 0
+local function check(name, actual, expected)
+    if actual == expected then print("OK   " .. name) else
+        failures = failures + 1
+        print(string.format("FAIL %s: forventede %s, fik %s", name, tostring(expected), tostring(actual)))
+    end
+end
+
+-- M1: ny mark = venter, manuel ensilage uden riv
+local f = M.newField(109)
+check("M1 stage", f.stage, "idle")
+check("M1 mode", f.plan.mode, "manual")
+check("M1 product", f.plan.product, "silage")
+check("M1 rake", f.plan.rake, false)
+
+-- M2: klar ved >= 90 %
+check("M2 89 % ikke klar", M.onReadiness(f, 0.89).stage, "idle")
+local ready = M.onReadiness(f, 0.9)
+check("M2 90 % klar", ready.stage, "ready")
+check("M2 immutabel", f.stage, "idle")
+
+-- M3: klar mark slået af spilleren -> tilbage til venter
+check("M3 slået manuelt", M.onReadiness(ready, 0.3).stage, "idle")
+check("M3 lidt under 90 % forbliver klar", M.onReadiness(ready, 0.8).stage, "ready")
+
+-- M4: trin pr. plan
+check("M4 ensilage", table.concat(M.workStages({product = "silage"}), ","), "mowing,collecting")
+check("M4 hø", table.concat(M.workStages({product = "hay", rake = false}), ","), "mowing,tedding,collecting")
+check("M4 hø m. riv", table.concat(M.workStages({product = "hay", rake = true}), ","), "mowing,tedding,raking,collecting")
+
+-- M5: start: auto starter selv, manuel kun på forespørgsel
+check("M5 manuel starter ikke", M.shouldStart(ready), false)
+local auto = M.onReadiness(M.newField(5), 1)
+auto.plan.mode = "auto"
+check("M5 auto starter", M.shouldStart(auto), true)
+local requested = M.newField(6); requested.stage = "ready"; requested.startRequested = true
+check("M5 Start nu", M.shouldStart(requested), true)
+local started = M.start(ready)
+check("M5 start -> slås", started.stage, "mowing")
+check("M5 start rydder forespørgsel", started.startRequested, false)
+
+-- M6: videre gennem trinene; færdig mark bliver klar igen når den er vokset
+local hay = M.start(M.onReadiness(M.newField(7), 1)); hay.plan.product = "hay"
+hay = M.advance(hay); check("M6 hø -> vendes", hay.stage, "tedding")
+hay = M.advance(hay); check("M6 -> samles op", hay.stage, "collecting")
+hay = M.advance(hay); check("M6 -> færdig", hay.stage, "done")
+check("M6 færdig forbliver ved lav andel", M.onReadiness(hay, 0.1).stage, "done")
+check("M6 færdig -> klar når vokset", M.onReadiness(hay, 0.95).stage, "ready")
+check("M6 arbejdende mark ignorerer andel", M.onReadiness(started, 0).stage, "mowing")
+check("M6 isWorking", M.isWorking(started), true)
+check("M6 stop -> klar", M.stop(started).stage, "ready")
+
+-- M7: roller, maks sæt, bredde
+check("M7 rolle slå", M.roleFor("mowing"), "mower")
+check("M7 rolle saml", M.roleFor("collecting"), "collector")
+check("M7 rolle klar = ingen", M.roleFor("ready"), nil)
+check("M7 maks læssevogne", M.maxRigs("collecting"), 2)
+check("M7 maks slå", M.maxRigs("mowing"), 1)
+local okWide, whyWide = M.checkWidth("mower", 60, nil)
+check("M7 over 50 m", okWide, false); check("M7 grund", whyWide, "tooWide")
+check("M7 40,8 m slå ok", (M.checkWidth("mower", 40.8, nil)), true)
+local okNarrow, whyNarrow, args = M.checkWidth("collector", 20, 40.8)
+check("M7 for smal", okNarrow, false); check("M7 grund smal", whyNarrow, "tooNarrow"); check("M7 args", args[2], 40.8)
+check("M7 lige bred ok (tolerance)", (M.checkWidth("collector", 40.76, 40.8)), true)
+check("M7 ukendt slåbredde ok", (M.checkWidth("tedder", 10, nil)), true)
+
+-- wantsRig: kun arbejdende trin, under maks, efter pause
+check("M7 wantsRig slå", M.wantsRig(started, 0, 0), "mower")
+check("M7 wantsRig fuld", M.wantsRig(started, 1, 0), nil)
+local paused = M.start(M.onReadiness(M.newField(8), 1)); paused.retryAt = 1000
+check("M7 wantsRig i pause", M.wantsRig(paused, 0, 500), nil)
+check("M7 wantsRig efter pause", M.wantsRig(paused, 0, 1000), "mower")
+check("M7 wantsRig klar = nil", M.wantsRig(ready, 0, 0), nil)
+
+-- M8: gem/indlæs bevarer trin, plan og slåbredde
+local saved = M.advance(M.start(M.onReadiness(M.newField(109), 1))); saved.mowWidth = 40.8
+saved.plan = {mode = "auto", product = "hay", rake = true, storeBuildingIds = {"b12", "b7"}}
+local back = M.fromRecord(M.toRecord(saved))
+check("M8 id", back.id, 109)
+check("M8 stage", back.stage, saved.stage)
+check("M8 mode", back.plan.mode, "auto")
+check("M8 product", back.plan.product, "hay")
+check("M8 rake", back.plan.rake, true)
+check("M8 lager", table.concat(back.plan.storeBuildingIds, " "), "b12 b7")
+check("M8 slåbredde", back.mowWidth, 40.8)
+check("M8 ukendt trin -> venter", M.fromRecord({id = 3, stage = "bogus"}).stage, "idle")
+
+-- M9: with() kopierer og fletter planen
+local base = M.start(M.onReadiness(M.newField(1), 1))
+local noted = M.with(base, {reason = {text = "x"}, retryAt = 5, plan = {product = "hay"}})
+check("M9 grund", noted.reason.text, "x"); check("M9 pause", noted.retryAt, 5)
+check("M9 plan flettet", noted.plan.product, "hay"); check("M9 mode bevaret", noted.plan.mode, "manual")
+check("M9 trin bevaret", noted.stage, "mowing"); check("M9 original urørt", base.plan.product, "silage")
+
+print(failures == 0 and "\nALLE TESTS OK" or ("\n" .. failures .. " FEJL"))
+os.exit(failures == 0 and 0 or 1)