local changeDelay = CreateConVar(
    "gc_mapchangedelay",
    "8",
    FCVAR_ARCHIVE,
    "Seconds between map completion and loading the next coop map"
)

local maxMapTime = CreateConVar(
    "gc_mapmaxtime",
    "3600",
    FCVAR_ARCHIVE,
    "Maximum map time in seconds before rotating; 0 disables the time limit"
)

local changeQueued = false

local function MapExists(mapName)
    if not mapName or mapName == "" then return false end

    local wanted = string.lower(string.StripExtension(mapName))
    for _, fileName in ipairs(file.Find("maps/*.bsp", "GAME")) do
        if string.lower(string.StripExtension(fileName)) == wanted then
            return true
        end
    end

    return false
end

local function SetFreshNextLevel()
    local nextLevel = GetConVar("nextlevel"):GetString()
    if nextLevel == "" or not MapExists(nextLevel) or string.lower(nextLevel) == string.lower(game.GetMap()) then
        nextLevel = NextRandomLevel()
    end
    return nextLevel
end

function QueueCoopMapChange(reason, requestedMap)
    if changeQueued then return end

    local destination = requestedMap and string.lower(requestedMap) or nil
    if not MapExists(destination) or destination == string.lower(game.GetMap()) then
        destination = SetFreshNextLevel()
    end

    if not destination then
        ErrorNoHalt("[custom_coop] Map completed, but no installed destination map is available\n")
        return
    end

    changeQueued = true
    local delay = math.max(changeDelay:GetFloat(), 0)
    PrintMessage(HUD_PRINTTALK, "Map complete! Loading " .. destination .. " in " .. math.ceil(delay) .. " seconds.")
    print("[custom_coop] Map change queued by " .. (reason or "unknown") .. ": " .. destination)

    timer.Create("CustomCoopChangeCompletedMap", delay, 1, function()
        RunConsoleCommand("changelevel", destination)
    end)
end

hook.Add("AcceptInput", "CustomCoopDetectMapCompletion", function(ent, inputName, _, _, value)
    if not IsValid(ent) then return end

    local className = string.lower(ent:GetClass())
    local input = string.lower(inputName or "")

    if className == "game_end" and input == "endgame" then
        QueueCoopMapChange("game_end")
        return true
    end

    if className ~= "point_servercommand" or input ~= "command" then return end

    local command = string.lower(string.Trim(tostring(value or "")))
    local requestedMap = string.match(command, "^changelevel%s+[%\"]?([%w_%-%[%]!]+)")
        or string.match(command, "^map%s+[%\"]?([%w_%-%[%]!]+)")

    if requestedMap and (not MapExists(requestedMap) or string.lower(requestedMap) == string.lower(game.GetMap())) then
        QueueCoopMapChange("point_servercommand", requestedMap)
        return true
    end
end)

-- Repair old trigger_changelevel/point_changelevel entities that refer to a map
-- which is not mounted. Valid campaign destinations remain untouched.
hook.Add("EntityKeyValue", "CustomCoopRepairChangelevelTargets", function(ent, key, value)
    local className = string.lower(ent:GetClass())
    if className ~= "trigger_changelevel" and className ~= "point_changelevel" then return end
    if string.lower(key or "") ~= "map" then return end
    if MapExists(value) and string.lower(value) ~= string.lower(game.GetMap()) then return end

    local replacement = GetRandomLevel()
    if replacement then
        print("[custom_coop] Replacing unavailable changelevel target '" .. tostring(value) .. "' with " .. replacement)
        return replacement
    end
end)

hook.Add("InitPostEntity", "CustomCoopStartMapTimeLimit", function()
    SetFreshNextLevel()

    local limit = maxMapTime:GetFloat()
    if limit <= 0 then return end

    timer.Create("CustomCoopMapTimeLimit", limit, 1, function()
        QueueCoopMapChange("time limit")
    end)
end)