using UnityEngine;
using UnityEngine.UIElements;

namespace Ironspore
{
    // Field-only instruments. Weapon state and navigation targets belong to the simulation.
    public sealed class CombatInstruments
    {
        readonly VisualElement field, map;
        readonly GameSession game;
        readonly Label primary, rounds, reload, secondary, cargo;
        readonly string reloadHint;
        float nextMapUpdate;
        int displayedRounds = -1;

        public CombatInstruments(VisualElement field, VisualElement vitals, GameSession game)
        {
            this.field = field;
            this.game = game;
            var nav = Panel("combat-nav");
            Caption(nav, GameLocalization.Text("ui.combat.nav") + "     N ↑", "combat-kicker");
            map = new VisualElement();
            map.AddToClassList("combat-map");
            nav.Add(map);
            map.generateVisualContent += DrawMap;
            Caption(nav, GameLocalization.Text("ui.combat.legend"), "combat-small");

            var weapon = Panel("combat-weapon");
            primary = Caption(weapon, "", "combat-primary");
            Caption(weapon, GameLocalization.Text("ui.combat.ammo"), "combat-kicker");
            var row = new VisualElement();
            row.AddToClassList("combat-rounds-row");
            weapon.Add(row);
            rounds = Caption(row, "", "combat-rounds");
            reload = Caption(row, "", "combat-small");
            secondary = Caption(weapon, "", "combat-secondary");
            cargo = Caption(vitals, "", "combat-cargo");
            reloadHint = GameLocalization.Text("ui.combat.reload", game.Settings.Bindings.Display("Reload"));
        }

        VisualElement Panel(string style)
        {
            var panel = new VisualElement();
            panel.AddToClassList("combat-panel");
            panel.AddToClassList(style);
            field.Add(panel);
            return panel;
        }

        static Label Caption(VisualElement parent, string text, string style)
        {
            var label = new Label(text);
            label.AddToClassList(style);
            parent.Add(label);
            return label;
        }

        public void Refresh()
        {
            var pilot = game.Pilot;
            field.EnableInClassList("cockpit-hud", pilot.FirstPerson);
            bool redraw = Time.unscaledTime >= nextMapUpdate;
            if (!redraw && pilot.Rounds == displayedRounds) return;
            displayedRounds = pilot.Rounds;
            primary.text = pilot.Primary.LocalizedName;
            rounds.text = pilot.Rounds.ToString();
            rounds.EnableInClassList("ammo-low", pilot.Rounds <= pilot.Primary.magazineSize / 4);
            reload.text = pilot.ReloadRemaining > 0 ? GameLocalization.Text("ui.combat.loading", pilot.ReloadRemaining) : reloadHint;
            var state = pilot.SecondaryCooldown > 0 ? GameLocalization.Text("ui.combat.charging", pilot.SecondaryCooldown) :
                GameLocalization.Text(pilot.Energy < 15 ? "ui.combat.lowEnergy" : "ui.combat.ready");
            secondary.text = game.Part(1, game.Run.equipment[1]).LocalizedName + "   ·   " + state;
            cargo.text = GameLocalization.Text("ui.combat.cargo", game.Run.cargo.Count);
            if (redraw)
            {
                map.MarkDirtyRepaint();
                nextMapUpdate = Time.unscaledTime + .075f;
            }
        }

        void DrawMap(MeshGenerationContext context)
        {
            var pilot = game.Pilot;
            if (!pilot || !game.InField) return;
            var painter = context.painter2D;
            var rect = map.contentRect;
            // Keep north up and use one scale on both axes. Include the pilot past the yard edges.
            var position = pilot.transform.position;
            var scale = Mathf.Min(rect.width / Mathf.Max(90, Mathf.Abs(position.x) * 2 + 8),
                rect.height / Mathf.Max(100, Mathf.Abs(position.z - 8) * 2 + 8));
            Vector2 Project(float x, float z) => rect.center + new Vector2(x, 8 - z) * scale;
            void Line(Vector2 a, Vector2 b)
            {
                painter.BeginPath(); painter.MoveTo(a); painter.LineTo(b); painter.Stroke();
            }
            painter.lineWidth = 1;
            painter.strokeColor = new Color(.15f, .28f, .30f);
            for (int x = -30; x <= 30; x += 10) Line(Project(x, -40), Project(x, 56));
            for (int z = -40; z <= 50; z += 10) Line(Project(-35, z), Project(35, z));
            painter.lineWidth = 2;
            painter.strokeColor = new Color(.33f, .49f, .5f);
            Line(Project(-35, -38), Project(-35, 58));
            Line(Project(35, -38), Project(35, 58));
            painter.fillColor = painter.strokeColor;
            for (int i = 0; i < game.World.Cover.Count; i++)
            {
                var box = game.World.Cover[i];
                painter.BeginPath(); painter.MoveTo(Project(box.xMin, box.yMin));
                painter.LineTo(Project(box.xMax, box.yMin)); painter.LineTo(Project(box.xMax, box.yMax));
                painter.LineTo(Project(box.xMin, box.yMax)); painter.ClosePath(); painter.Fill();
            }
            var target = game.World.NavigationTarget;
            if (target)
            {
                var pos = Project(target.position.x, target.position.z);
                painter.strokeColor = new Color(.45f, .84f, 1);
                painter.BeginPath(); painter.MoveTo(pos + Vector2.up * 6);
                painter.LineTo(pos + Vector2.right * 6); painter.LineTo(pos + Vector2.down * 6);
                painter.LineTo(pos + Vector2.left * 6); painter.ClosePath(); painter.Stroke();
            }
            var pad = game.World.ExtractionPosition;
            painter.strokeColor = game.World.TransportReady ? Color.green : new Color(1, .72f, .36f);
            painter.BeginPath(); painter.Arc(Project(pad.x, pad.z), 6, 0, 360); painter.Stroke();
            var origin = Project(position.x, position.z);
            var radians = pilot.Heading * Mathf.Deg2Rad;
            var forward = new Vector2(Mathf.Sin(radians), -Mathf.Cos(radians));
            var right = new Vector2(-forward.y, forward.x);
            painter.fillColor = new Color(.43f, 1, .80f);
            painter.BeginPath(); painter.MoveTo(origin + forward * 9);
            painter.LineTo(origin - forward * 6 + right * 5); painter.LineTo(origin - forward * 6 - right * 5);
            painter.ClosePath(); painter.Fill();
        }
    }
}