-- 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

-- Start nu fra menuen på en mark der ikke er nået 90 %: den behandles som klar.
function ADFieldModel.forceReady(field)
    if field.stage == "idle" or field.stage == "done" then
        return ADFieldModel.with(field, {stage = "ready"})
    end
    return field
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
    copy.mowVehicleId = 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,
        mowVehicle = field.mowVehicleId or "",
    }
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
    field.mowVehicleId = record.mowVehicle ~= nil and record.mowVehicle ~= "" and record.mowVehicle or nil
    return field
end