using System.Drawing;
using CounterStrikeSharp.API;
using CounterStrikeSharp.API.Core;
using CounterStrikeSharp.API.Modules.Utils;

namespace Outnumbered.Engine;

// The one place a point_worldtext entity is created + configured (HUD panel, the 2 shop panels, the draft cards all
// share it). CreateEntityByName returns a NON-null wrapper even on failure (e.g. the entity limit) with a Zero Handle,
// so the guard checks the raw handle (no memory deref) before touching schema members. Callers supply the per-use
// font/justify/colour/border and own the last-text caching; the volatile "SetMessage" input + the Teleport placement
// go through SetText/Place so every engine touchpoint for this entity lives here.
internal static class WorldText
{
    public static CPointWorldText? Create(float fontSize, float worldUnitsPerPx, string fontName, Color color,
        bool drawBackground, float border, PointWorldTextJustifyHorizontal_t justify)
    {
        var e = Utilities.CreateEntityByName<CPointWorldText>(EngineNames.PointWorldText);
        if (e is null || e.Handle == nint.Zero) return null;
        e.MessageText = " ";
        e.Enabled = true;
        e.Fullbright = true;
        e.FontSize = fontSize;
        e.WorldUnitsPerPx = worldUnitsPerPx;
        if (!string.IsNullOrEmpty(fontName)) e.FontName = fontName;
        e.Color = color;
        e.JustifyHorizontal = justify;
        e.JustifyVertical = PointWorldTextJustifyVertical_t.POINT_WORLD_TEXT_JUSTIFY_VERTICAL_CENTER;
        e.ReorientMode = PointWorldTextReorientMode_t.POINT_WORLD_TEXT_REORIENT_NONE;
        e.DrawBackground = drawBackground;
        e.BackgroundBorderHeight = border;
        e.BackgroundBorderWidth = border;
        e.DispatchSpawn();
        return e;
    }

    // Push new text via the point_worldtext "SetMessage" input (the volatile input-name literal lives here, not at the 4
    // call sites). Callers keep their own last-text cache and only call this on a change.
    public static void SetText(CPointWorldText ent, string text) => ent.AcceptInput("SetMessage", ent, ent, text);

    // Position + orient a panel. point_worldtext is moved via Teleport (no velocity); callers compute the eye-relative frame.
    public static void Place(CPointWorldText ent, Vector pos, QAngle ang) => ent.Teleport(pos, ang, null);

    // Tear a panel down: Remove the entity if it's still live, then null the caller's reference. Symmetric with Create —
    // every point_worldtext create + destroy goes through this file.
    public static void Destroy(ref CPointWorldText? ent)
    {
        if (ent is { IsValid: true }) ent.Remove();
        ent = null;
    }

    public const float EyeZFallback = 64f; // ViewOffset.Z fallback when the pawn doesn't report one

    // The eye-relative frame for placing a panel in front of a pawn's view: eye position + forward/right/up basis + the
    // panel orientation (yaw+270 / 90-pitch = worldtext faces the player, upright across pitch/yaw). false if AbsOrigin is
    // null. Callers add only their own per-panel offsets. Shared by the HUD + the shop/draft panels.
    public static bool TryEyeFrame(CCSPlayerPawn pawn, out Vector eye, out Vector fwd, out Vector right, out Vector up, out QAngle ang)
    {
        eye = null!; fwd = null!; right = null!; up = null!; ang = null!;
        var origin = pawn.AbsOrigin;
        if (origin is null) return false;
        var ea = pawn.EyeAngles;
        float eyeZ = pawn.ViewOffset?.Z ?? EyeZFallback;
        (fwd, right, up) = AngleVectors(ea);
        eye = new Vector(origin.X, origin.Y, origin.Z + eyeZ);
        ang = new QAngle(0f, ea.Y + 270f, 90f - ea.X);
        return true;
    }

    // Source-engine AngleVectors with roll assumed 0 (HUD/shop panels never roll).
    private static (Vector forward, Vector right, Vector up) AngleVectors(QAngle a)
    {
        const double d2r = Math.PI / 180.0;
        double p = a.X * d2r, y = a.Y * d2r;
        double sp = Math.Sin(p), cp = Math.Cos(p), sy = Math.Sin(y), cy = Math.Cos(y);
        return (
            new Vector((float)(cp * cy), (float)(cp * sy), (float)(-sp)),
            new Vector((float)sy, (float)(-cy), 0f),
            new Vector((float)(sp * cy), (float)(sp * sy), (float)cp));
    }
}