using System;
using System.Numerics;
using Dalamud.Bindings.ImGui;
using FFXIVClientStructs.FFXIV.Client.UI.Agent;
using FFXIVClientStructs.FFXIV.Client.UI.Arrays;
using Mappy.Classes;
using Mappy.Extensions;

namespace Mappy.MapRenderer;

public partial class MapRenderer
{
    private unsafe void DrawPlayer()
    {
        if (AgentMap.Instance()->SelectedMapId != AgentMap.Instance()->CurrentMapId) return;

        if (Service.ObjectTable.LocalPlayer is { } localPlayer) {
            var position = ImGui.GetWindowPos() +
                           DrawPosition +
                           (localPlayer.GetMapPosition() -
                            DrawHelpers.GetMapOffsetVector() +
                            DrawHelpers.GetMapCenterOffsetVector()) * Scale;

            DrawLookLine(position);
            DrawPlayerIcon(position);
        }
    }

    private void DrawLookLine(Vector2 position)
    {
        var angle = GetCameraRotation();

        var lineLength = System.SystemConfig.ConeSize * (System.SystemConfig.ScalePlayerCone ? 1.0f : Scale);
        var halfConeAngle = DegreesToRadians(90.0f) / 2.0f;

        DrawAngledLineFromCenter(position, lineLength, angle - halfConeAngle);
        DrawAngledLineFromCenter(position, lineLength, angle + halfConeAngle);
        DrawLineArcFromCenter(position, lineLength, angle);

        DrawFilledSemiCircle(position, lineLength, angle);
    }

    private static void DrawAngledLineFromCenter(Vector2 center, float lineLength, float angle, Vector4? outlineColor = null)
    {
        var lineSegment = new Vector2(lineLength * MathF.Cos(angle), lineLength * MathF.Sin(angle));
        var color = outlineColor ?? System.SystemConfig.PlayerConeOutlineColor;
        ImGui.GetWindowDrawList().AddLine(center, center + lineSegment, ImGui.GetColorU32(color), 3.0f);
    }

    private static void DrawLineArcFromCenter(Vector2 center, float distance, float rotation, Vector4? outlineColor = null)
    {
        var halfConeAngle = DegreesToRadians(90.0f) / 2.0f;
        var color = outlineColor ?? System.SystemConfig.PlayerConeOutlineColor;

        var start = rotation - halfConeAngle;
        var stop = rotation + halfConeAngle;

        ImGui.GetWindowDrawList().PathArcTo(center, distance, start, stop);
        ImGui.GetWindowDrawList().PathStroke(ImGui.GetColorU32(color), ImDrawFlags.None, 3.0f);
    }

    private static void DrawFilledSemiCircle(Vector2 center, float distance, float rotation)
    {
        var halfConeAngle = DegreesToRadians(90.0f) / 2.0f;

        var coneColor = ImGui.GetColorU32(System.SystemConfig.PlayerConeColor);
        var startAngle = rotation - halfConeAngle;
        var stopAngle = rotation + halfConeAngle;

        var startPosition = new Vector2(distance * MathF.Cos(rotation - halfConeAngle), distance * MathF.Sin(rotation - halfConeAngle));

        ImGui.GetWindowDrawList().PathArcTo(center, distance, startAngle, stopAngle);
        ImGui.GetWindowDrawList().PathLineTo(center);
        ImGui.GetWindowDrawList().PathLineTo(center + startPosition);
        ImGui.GetWindowDrawList().PathFillConvex(coneColor);
    }

    private static unsafe float GetCameraRotation() => -DegreesToRadians(AreaMapNumberArray.Instance()->ConeRotation) - 0.5f * MathF.PI;

    private static float DegreesToRadians(float degrees) => MathF.PI / 180.0f * degrees;

    private void DrawPlayerIcon(Vector2 position)
    {
        if (!System.SystemConfig.ShowPlayerIcon) return;
        if (Service.ObjectTable is not { LocalPlayer: { } player }) return;

        var texture = Service.TextureProvider.GetFromGameIcon(60443).GetWrapOrEmpty();
        var angle = -player.Rotation + MathF.PI / 2.0f;

        var scale = System.SystemConfig.ScaleWithZoom ? Scale : 1.0f;
        scale *= System.SystemConfig.PlayerIconScale;

        var vectors = GetRotationVectors(angle, position, texture.Size / 2.0f * scale);

        ImGui.GetWindowDrawList().AddImageQuad(texture.Handle, vectors[0], vectors[1], vectors[2], vectors[3]);
    }

    /// <summary>
    /// Draw only the minimap player cone (direction indicator). Call before DrawMinimapMarkers so markers draw on top of the cone.
    /// </summary>
    private void DrawMinimapConeAtCenter(Vector2 centerPos, float mapScale)
    {
        if (!System.SystemConfig.MinimapShowPlayerCone) return;
        var angle = GetCameraRotation();
        var lineLength = System.SystemConfig.ConeSize * 0.5f;
        var halfConeAngle = DegreesToRadians(90.0f) / 2.0f;
        DrawMinimapConeGradient(centerPos, lineLength, angle - halfConeAngle, angle + halfConeAngle);
        var softWhite = new Vector4(1f, 1f, 1f, 0.2f);
        DrawAngledLineFromCenter(centerPos, lineLength, angle - halfConeAngle, softWhite);
        DrawAngledLineFromCenter(centerPos, lineLength, angle + halfConeAngle, softWhite);
        DrawLineArcFromCenter(centerPos, lineLength, angle, softWhite);
    }

    /// <summary>
    /// Draw player icon at center (for minimap). Cone is drawn earlier so markers can be drawn on top of it.
    /// </summary>
    private void DrawPlayerAtCenter(Vector2 centerPos, float mapScale)
    {
        if (Service.ObjectTable.LocalPlayer is not { } localPlayer) return;
        if (!System.SystemConfig.ShowPlayerIcon) return;

        var texture = Service.TextureProvider.GetFromGameIcon(60443).GetWrapOrEmpty();
        var angle = -localPlayer.Rotation + MathF.PI / 2.0f;
        var iconScale = System.SystemConfig.PlayerIconScale * 1.5f; // 1.5x for minimap visibility
        var vectors = GetRotationVectors(angle, centerPos, texture.Size / 2.0f * iconScale);
        ImGui.GetWindowDrawList().AddImageQuad(texture.Handle, vectors[0], vectors[1], vectors[2], vectors[3]);
    }

    /// <summary>Draw minimap cone as white light with radial gradient (bright at center, fading at edge). Kept quite transparent so markers underneath remain visible.</summary>
    private static void DrawMinimapConeGradient(Vector2 center, float radius, float startAngle, float endAngle)
    {
        const int segments = 24;
        const float maxAlpha = 0.18f;
        var drawList = ImGui.GetWindowDrawList();
        for (var j = segments - 1; j >= 0; j--) {
            var rInner = radius * j / segments;
            var rOuter = radius * (j + 1) / segments;
            var t = (j + 0.5f) / segments;
            var alpha = maxAlpha * (1f - t);
            if (alpha <= 0f) continue;
            var color = ImGui.GetColorU32(new Vector4(1f, 1f, 1f, alpha));
            var outerStart = center + new Vector2(rOuter * MathF.Cos(startAngle), rOuter * MathF.Sin(startAngle));
            var innerEnd = center + new Vector2(rInner * MathF.Cos(endAngle), rInner * MathF.Sin(endAngle));
            drawList.PathClear();
            drawList.PathLineTo(center);
            drawList.PathLineTo(outerStart);
            drawList.PathArcTo(center, rOuter, startAngle, endAngle);
            drawList.PathLineTo(innerEnd);
            drawList.PathArcTo(center, rInner, endAngle, startAngle);
            drawList.PathFillConvex(color);
        }
    }

    private static Vector2[] GetRotationVectors(float angle, Vector2 center, Vector2 size)
    {
        var cosA = MathF.Cos(angle + 0.5f * MathF.PI);
        var sinA = MathF.Sin(angle + 0.5f * MathF.PI);

        Vector2[] vectors =
        [
            center + ImRotate(new Vector2(-size.X * 0.5f, -size.Y * 0.5f), cosA, sinA),
            center + ImRotate(new Vector2(+size.X * 0.5f, -size.Y * 0.5f), cosA, sinA),
            center + ImRotate(new Vector2(+size.X * 0.5f, +size.Y * 0.5f), cosA, sinA),
            center + ImRotate(new Vector2(-size.X * 0.5f, +size.Y * 0.5f), cosA, sinA),
        ];
        return vectors;
    }

    private static Vector2 ImRotate(Vector2 v, float cosA, float sinA) => new(v.X * cosA - v.Y * sinA, v.X * sinA + v.Y * cosA);
}