using System.Linq;
using System.Text;
using HarmonyLib;
using Model;
using Model.Physics;
using UI.Console;

namespace RailroaderPhysicsOverhaul;

/// <summary>
/// Hooks into ConsoleCommandHandler._HandleSlashCommand to add /rpf commands
/// before the game's switch block sees them.
/// </summary>
[HarmonyPatch(typeof(ConsoleCommandHandler))]
[HarmonyPatch("_HandleSlashCommand")]
static class ConsoleCommandPatch
{
    static bool Prefix(string[] comps, ref string __result)
    {
        if (comps.Length == 0 || comps[0].ToLower() != "/rpf")
            return true; // not our command, let original handle it

        __result = RpfCommands.Handle(comps);
        return false; // swallow — don't pass to original
    }
}

static class RpfCommands
{
    internal static string Handle(string[] comps)
    {
        if (comps.Length < 2)
            return Usage();

        return comps[1].ToLower() switch
        {
            "freeze"      => Freeze(),
            "unfreeze"    => Unfreeze(),
            "dump"        => Dump(),
            "timing"      => PhysicsTimer.GetReport(),
            "overlay"     => ToggleOverlay(),
            "forceactive" => ToggleForceActive(),
            "lod"         => SetLod(comps),
            "help"        => Usage(),
            _             => $"Unknown subcommand '{comps[1]}'. {Usage()}",
        };
    }

    static string Freeze()
    {
        var (car, set) = GetSelection();
        if (car == null) return "No car selected.";
        if (set == null) return $"{car.id} has no IntegrationSet.";

        // Zero velocities so cars stop cleanly before we freeze the solver.
        set.SetVelocity(0f, set.Cars.ToList());
        bool added = ConsistFreezer.Freeze(set.Id);
        return added
            ? $"Froze set #{set.Id} ({set.NumberOfCars} cars). Use /rpf unfreeze to release."
            : $"Set #{set.Id} was already frozen.";
    }

    static string Unfreeze()
    {
        var (car, set) = GetSelection();
        if (car == null) return "No car selected.";
        if (set == null) return $"{car.id} has no IntegrationSet.";

        bool removed = ConsistFreezer.Unfreeze(set.Id);
        return removed
            ? $"Unfroze set #{set.Id} — solver resumed."
            : $"Set #{set.Id} was not frozen.";
    }

    static string Dump()
    {
        var (car, set) = GetSelection();
        if (car == null) return "No car selected.";
        if (set == null) return $"{car.id} has no IntegrationSet.";

        var sb = new StringBuilder();
        sb.AppendLine($"=== IntegrationSet #{set.Id} | {set.NumberOfCars} cars | frozen={ConsistFreezer.IsFrozen(set.Id)} ===");

        float totalWeightLbs = 0f;
        int idx = 0;
        foreach (Car c in set.Cars)
        {
            totalWeightLbs += c.Weight;
            float mph = c.velocity * 2.23694f;
            string coupled = c.EndGearA.IsCoupled ? "A" : "";
            coupled += c.EndGearB.IsCoupled ? "B" : "";
            if (coupled == "") coupled = "solo";
            sb.AppendLine($"  [{idx++}] {c.id} {c.DisplayName} | {mph:F1}mph | {c.Weight:F0}lb | coupled={coupled} | loc={c.WheelBoundsF.segment?.id}");
        }

        sb.AppendLine($"Total: {totalWeightLbs / 2000f:F0} short tons");
        return sb.ToString();
    }

    static (Car car, IntegrationSet set) GetSelection()
    {
        Car car = TrainController.Shared?.SelectedCar;
        return (car, car?.set);
    }

    static string ToggleOverlay()
    {
        var gui = PhysicsOverlayGUI.Instance;
        if (gui == null) return "Overlay not initialized.";
        gui.Visible = !gui.Visible;
        return $"Overlay {(gui.Visible ? "shown" : "hidden")}.";
    }

    static string SetLod(string[] comps)
    {
        if (comps.Length < 3)
        {
            ConsistLOD.Enabled = !ConsistLOD.Enabled;
            return $"LOD {(ConsistLOD.Enabled ? "enabled" : "disabled")}. Threshold: {ConsistLOD.DistanceThreshold:F0}m. Usage: /rpf lod <meters|off>";
        }
        if (comps[2].ToLower() == "off") { ConsistLOD.Enabled = false; return "LOD disabled."; }
        if (float.TryParse(comps[2], out float dist) && dist > 0f)
        {
            ConsistLOD.DistanceThreshold = dist;
            ConsistLOD.Enabled = true;
            return $"LOD enabled, fast path for interior cars beyond {dist:F0}m.";
        }
        return "Usage: /rpf lod <meters>  or  /rpf lod off";
    }

    static string ToggleForceActive()
    {
        PhysicsTimer.ForceActive = !PhysicsTimer.ForceActive;
        return PhysicsTimer.ForceActive
            ? "ForceActive ON — stock optimizer bypassed, solver always runs."
            : "ForceActive OFF — stock optimizer active.";
    }

    static string Usage() =>
        "Usage: /rpf <freeze|unfreeze|dump|timing|overlay|forceactive|lod|help>";
}