-- AD Pool
-- Maskinpulje: plove, kultivatorer, såmaskiner … holder frakoblet på deres AD-parkering "X", og en ledig
-- solo-traktor henter dem via markøren "Connect X", når markarbejdet mangler en færdig kombination.
-- Ren logik øverst (testes med luajit), spil-adapter nederst.

ADPool = {}
ADPool.LOG_PREFIX = "ADSmartPickup: pulje: "
ADPool.QUARANTINE_MS = 600000 -- redskab der ikke kunne kobles på, springes over så længe

-- ---- ren logik ----

-- Rolle for et frakoblet redskab ud fra dets egne specs (samme prioritet som markflåden); en ren vogn med
-- tip/snegl er tømmevogn.
function ADPool.roleOf(specs)
    local role = ADFieldFleet.roleFromSpecs(specs)
    if role ~= nil and role ~= "unloader" then return role end
    if specs.spec_trailer and specs.spec_dischargeable then return "unloader" end
    return role
end

-- Butiksdata er enten et tal eller en tabel pr. konfiguration: største tal, ellers nil.
function ADPool.numberOf(value)
    if type(value) == "number" then return value end
    if type(value) ~= "table" then return nil end
    local best = nil
    for _, entry in pairs(value) do
        if type(entry) == "number" and (best == nil or entry > best) then best = entry end
    end
    return best
end

-- Mangler et af tallene, tillades det (intet må gå i stå på manglende data).
function ADPool.powerOk(tractorHp, neededHp)
    if tractorHp == nil or neededHp == nil or tractorHp <= 0 or neededHp <= 0 then return true end
    return tractorHp >= neededHp
end

-- Markøren "Connect <parkering>" for en parkering (navneregel).
function ADPool.connectFor(parkName, markers)
    if type(parkName) ~= "string" then return nil end
    local wanted = parkName:lower()
    for _, marker in pairs(markers or {}) do
        local action, target = ADHitch.parseMarker(marker.name)
        if action == "attach" and target ~= nil and target:lower() == wanted then return marker end
    end
    return nil
end

local function hasRole(item, role)
    return item.role == role or (item.roles ~= nil and item.roles[role] == true)
end

local function distanceSq(ax, az, bx, bz)
    return (ax - bx) ^ 2 + (az - bz) ^ 2
end

local function nearest(items, x, z, keep)
    local best, bestDistance = nil, math.huge
    for _, item in ipairs(items) do
        if keep(item) then
            local distance = distanceSq(item.x, item.z, x, z)
            if distance < bestDistance then best, bestDistance = item, distance end
        end
    end
    return best
end

-- Redskab med rollen nærmest marken, derefter nærmeste ledige traktor med nok hk til redskabet.
-- blocked = {[id] = true} (reserverede og redskaber i karantæne). accept (valgfri): implement -> bool.
function ADPool.pairFor(role, fieldX, fieldZ, implements, tractors, blocked, accept)
    blocked = blocked or {}
    local free = {}
    for _, tractor in ipairs(tractors or {}) do
        if not blocked[tractor.id] then table.insert(free, tractor) end
    end
    local candidates = {}
    for _, implement in ipairs(implements or {}) do
        if hasRole(implement, role) and not blocked[implement.id] and (accept == nil or accept(implement)) then
            table.insert(candidates, implement)
        end
    end
    if #candidates == 0 then return nil, "noPoolImplement" end
    if #free == 0 then return nil, "noPoolTractor" end
    table.sort(candidates, function(a, b)
        return distanceSq(a.x, a.z, fieldX, fieldZ) < distanceSq(b.x, b.z, fieldX, fieldZ)
    end)
    local weakest = nil
    for _, implement in ipairs(candidates) do
        local tractor = nearest(free, implement.x, implement.z, function(t) return ADPool.powerOk(t.hp, implement.neededHp) end)
        if tractor ~= nil then return {implement = implement, tractor = tractor} end
        if weakest == nil or (implement.neededHp or 0) < weakest then weakest = implement.neededHp end
    end
    return nil, "tooWeak", {weakest or 0}
end

-- Ventende marker først (længst ventende først, lige -> lavest id); resten bagefter i oprindelig rækkefølge.
function ADPool.queueOrder(infos, waitingSince)
    local waiting, rest = {}, {}
    for _, info in ipairs(infos or {}) do
        if waitingSince ~= nil and waitingSince[info.id] ~= nil then table.insert(waiting, info) else table.insert(rest, info) end
    end
    table.sort(waiting, function(a, b)
        local wa, wb = waitingSince[a.id], waitingSince[b.id]
        if wa ~= wb then return wa < wb end
        return a.id < b.id
    end)
    for _, info in ipairs(rest) do table.insert(waiting, info) end
    return waiting
end

-- Reservationer (i hukommelsen): owner -> {id, ...}. Karantæne: id -> udløbstid.
local reservations, quarantined = {}, {}

function ADPool.reserve(owner, ids)
    reservations[owner] = ids
end

function ADPool.release(owner)
    reservations[owner] = nil
end

function ADPool.quarantine(id, nowMs)
    quarantined[id] = nowMs + ADPool.QUARANTINE_MS
end

function ADPool.blocked(nowMs)
    local result = {}
    for _, ids in pairs(reservations) do
        for _, id in ipairs(ids) do result[id] = true end
    end
    for id, untilMs in pairs(quarantined) do
        if nowMs < untilMs then result[id] = true end
    end
    return result
end