using System.Collections.Generic;
using Luneraria.Core;

namespace Luneraria.UI
{
    /// <summary>
    /// Deterministic lane threat for one team (port of scripts/luneraria/ui/lune_lane_threat.gd),
    /// read only from public state: building HP, the units on the battlefield (positions and HP,
    /// which every client also sees) and the public announcements of this round. It never reads
    /// drafts, gold, unannounced bookings or bot notes, so host and guest compute the same level.
    /// Positions are projected onto the lane, because a network guest has positions but no lane
    /// progress.
    ///
    /// RUHIG       nothing below applies
    /// UMKÄMPFT    a lane tower is below 85 %, an enemy attack champion is announced here, or
    ///             enemy units stand in the own half of the lane
    /// UNTER DRUCK the Grenzwacht fell or is below 50 %, enemies attack the Grenzwacht, the enemy
    ///             has more than 1.5 times the own unit HP in the own half, or the enemy boss
    ///             is deployed on this lane
    /// KRITISCH    both lane towers fell (base open), the Bastion is below 50 % after the
    ///             Grenzwacht fell, enemies attack the Bastion, or the enemy boss comes while the
    ///             Grenzwacht is already down
    /// </summary>
    public static class LuneLaneThreat
    {
        public const int Calm = 0;
        public const int Contested = 1;
        public const int Pressure = 2;
        public const int Critical = 3;
        public static readonly string[] Names = { "RUHIG", "UMKÄMPFT", "UNTER DRUCK", "KRITISCH" };
        public static readonly string[] Glyphs = { "check", "melee", "warning", "warning" };

        public sealed class Result
        {
            public int Level;
            public string Name = "";
            public readonly List<string> Reasons = new List<string>();
        }

        public sealed class Battle
        {
            public double Length;
            public int OwnCount;
            public int EnemyCount;
            public double OwnHp;
            public double EnemyHp;
            /// <summary>Deepest enemy position measured from the own base along the lane (infinity without enemies).</summary>
            public double EnemyDepth = double.PositiveInfinity;
            public double OwnFront;
        }

        static void Building(LuneMatch state, string id, out bool alive, out double fraction)
        {
            double maxHp = state.Map.BuildingDef(id)?.MaxHp ?? 1.0;
            if (state.Phase == Phase.Combat && state.Combat != null && state.Combat.Buildings.TryGetValue(id, out LuneUnit unit))
            {
                alive = unit.Alive;
                fraction = alive ? GdMath.Clamp(unit.Hp / GdMath.Max(1.0, maxHp), 0.0, 1.0) : 0.0;
                return;
            }
            double hp = state.BuildingHp.GetValueOrDefault(id, 0.0);
            alive = hp > 0.0;
            fraction = GdMath.Clamp(hp / GdMath.Max(1.0, maxHp), 0.0, 1.0);
        }

        static string Percent(double value)
        {
            return LuneUiTheme.Round(value * 100.0) + " %";
        }

        public static Result Evaluate(LuneMatch state, int team, string lane, ICollection<int> hidden = null)
        {
            var result = new Result();
            int level = Calm;
            string prefix = team == 0 ? "blau" : "rot";
            int enemy = 1 - team;
            Building(state, prefix + "_" + lane + "_outer", out bool outerAlive, out double outer);
            Building(state, prefix + "_" + lane + "_inner", out bool innerAlive, out double inner);
            if (!outerAlive && !innerAlive)
            {
                level = Critical;
                result.Reasons.Add("Grenzwacht und Bastion gefallen – der Weg zur Basis ist offen");
            }
            else if (!outerAlive)
            {
                level = Pressure;
                result.Reasons.Add("Grenzwacht gefallen");
                if (inner < .5)
                {
                    level = Critical;
                    result.Reasons.Add("Bastion bei " + Percent(inner));
                }
                else if (inner < .85)
                {
                    result.Reasons.Add("Bastion bei " + Percent(inner));
                }
            }
            else if (outer < .5)
            {
                level = Pressure;
                result.Reasons.Add("Grenzwacht bei " + Percent(outer));
            }
            else if (outer < .85)
            {
                level = Contested;
                result.Reasons.Add("Grenzwacht bei " + Percent(outer));
            }
            foreach (Announcement entry in state.Announcements())
            {
                if (entry.Team != enemy || entry.Lane != lane)
                    continue;
                if (entry.Kind == "boss")
                {
                    level = System.Math.Max(level, !outerAlive ? Critical : Pressure);
                    result.Reasons.Add("Gegnerische Schlundkrone greift hier an");
                }
                else
                {
                    level = System.Math.Max(level, Contested);
                    result.Reasons.Add("Angriffschampion " + LuneContent.Champions[entry.ChampionId].Name + " angekündigt");
                }
            }
            if (state.Phase == Phase.Combat && state.Combat != null)
            {
                Battle battle = Battlefield(state, team, lane, hidden);
                double length = battle.Length;
                if (battle.EnemyCount > 0)
                {
                    double deepest = battle.EnemyDepth;
                    double innerAt = length * state.Balance.InnerTowerFraction;
                    double outerAt = length * state.Balance.OuterTowerFraction;
                    double reach = state.Balance.TowerRange * .8;
                    if (deepest <= innerAt + reach)
                    {
                        level = Critical;
                        result.Reasons.Add("Gegner greifen die Bastion oder die Basis an");
                    }
                    else if (deepest <= outerAt + reach && outerAlive)
                    {
                        level = System.Math.Max(level, Pressure);
                        result.Reasons.Add("Gegner greifen die Grenzwacht an");
                    }
                    else if (deepest <= length * .5)
                    {
                        level = System.Math.Max(level, Contested);
                        result.Reasons.Add("Gegner in der eigenen Lanehälfte");
                    }
                    if (battle.EnemyHp > battle.OwnHp * 1.5 && deepest <= length * .5)
                    {
                        level = System.Math.Max(level, Pressure);
                        result.Reasons.Add(string.Format("Übermacht: {0} gegen {1} Einheiten", battle.EnemyCount, battle.OwnCount));
                    }
                }
            }
            result.Level = level;
            result.Name = Names[level];
            return result;
        }

        /// <summary>
        /// Units of both sides on one lane: counts, HP sums and the deepest enemy position measured
        /// from the own base along the lane (from positions only).
        /// </summary>
        /// <summary>Units on the lane in combat; S3: enemies in the fog (hidden) are not counted.</summary>
        public static Battle Battlefield(LuneMatch state, int team, string lane, ICollection<int> hidden = null)
        {
            LanePath path = state.Map.LanePaths[lane];
            var result = new Battle { Length = path.Length };
            if (state.Combat == null)
                return result;
            foreach (LuneUnit unit in state.Combat.Units)
            {
                if (!unit.Alive || !unit.IsMobile() || unit.Zone != "lane" || unit.Lane != lane || unit.Team > 1)
                    continue;
                if (hidden != null && hidden.Contains(unit.Id))
                    continue;
                double s = path.Project(unit.Position);
                double fromOwnBase = team == 0 ? s : path.Length - s;
                if (unit.Team == team)
                {
                    result.OwnCount++;
                    result.OwnHp += unit.Hp;
                    result.OwnFront = GdMath.Max(result.OwnFront, fromOwnBase);
                }
                else
                {
                    result.EnemyCount++;
                    result.EnemyHp += unit.Hp;
                    result.EnemyDepth = GdMath.Min(result.EnemyDepth, fromOwnBase);
                }
            }
            return result;
        }
    }
}