using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace TheSlimesJourney
{
    public static class ScriptHandler
    {
        private static Character definingEnemy;
        private static List<Character> definingEnemyList;

        private static List<bool> evaluationStack = new List<bool>();
        private static int scopeDepth = 0;
        private static UI ui;

        public static void SetUI(UI newUI)
        {
            ui = newUI;
        }

        public static void HandleScript(string[] script, Item source = null)
        {
            evaluationStack.Clear();
            scopeDepth = 0;

            for (int i = 0; i < script.Length; i++)
            {
                string currentLine = script[i];

                string[] split = currentLine.Split(new string[] { " " }, StringSplitOptions.RemoveEmptyEntries);
                if (split.Length > 0)
                {
                    string baseCommand = split[0];
                    string argument = Utils.RBQ(currentLine);

                    switch (baseCommand)
                    {
                        case "addenemy":
                            definingEnemy = new Character();
                            ParseEnemy(script, i);
                            definingEnemyList.Add(definingEnemy);
                            break;
                        case "additem":
                            Game.itemsToBeHandled.Add(new Item(argument));
                            break;
                        case "addstrength":
                            Game.player.strength += Convert.ToInt32(argument);
                            break;
                        case "adddefense":
                            Game.player.defense += Convert.ToInt32(argument);
                            break;
                        case "addhealth":
                            Game.player.health += Convert.ToInt32(argument);
                            Game.player.maxHealth += Convert.ToInt32(argument);
                            break;
                        case "ambushed": Game.ambushed = true; break;
                        case "call": ScriptHandler.HandleScript(new Event(argument).script); break;
                        case "clearenemies":
                            definingEnemyList = new List<Character>();
                            break;
                        case "combat":
                            Game.EnterCombat(definingEnemyList);
                            break;
                        case "damage":
                            Game.player.health -= Convert.ToInt32(argument);
                            break;
                        case "deathcheck":
                            if (Game.DeathCheck()) return;
                            break;
                        case "destroy":
                            if (Game.player.inventory.Contains(source)) Game.player.inventory.Remove(source);
                            break;
                        case "equip":
                            if (source.equipped)
                            {
                                ui.Print("You unequip the #purple#" + source.name + ".");
                                ui.Pause();
                                HandleScript(source.unequipScript, source);
                                source.equipped = false;
                            }
                            else
                            {
                                ui.Print("You equip the #purple#" + source.GetName() + ".");
                                ui.Pause();
                                HandleScript(source.equipScript, source);
                                source.equipped = true;
                            }
                            break;
                        case "gainexp":
                            Game.player.experience += Convert.ToInt32(argument);
                            break;
                        case "heal":
                            int amount = Game.player.Heal(Convert.ToInt32(argument));
                            ui.Print("#green#You heal " + amount + " health!");
                            break;
                        case "losestrength":
                            Game.player.strength -= Convert.ToInt32(argument);
                            break;
                        case "losedefense":
                            Game.player.defense -= Convert.ToInt32(argument);
                            break;
                        case "losehealth":
                            Game.player.health -= Convert.ToInt32(argument);
                            Game.player.maxHealth -= Convert.ToInt32(argument);
                            break;
                        case "move":
                            Game.ChangeLocation(argument);
                            break;
                        case "pause":
                            ui.Pause();
                            break;
                        case "recoverhp":
                            Game.player.FullHeal();
                            break;
                        case "return":
                            Game.Return();
                            break;
                        case "shuffle":
                            Game.ShuffleDeck();
                            break;
                        case "text":
                            ui.Print(argument);
                            break;
                        case "victoryevent":
                            Game.victoryEvent = argument;
                            break;
                        case "wingame":
                            Game.WinGame();
                            break;
                        case "}": scopeDepth--; break;

                        //Conditions
                        case "hasequipment":
                        case "hasflag":
                        case "hasskill":
                        case "notskill":
                            if (!Evaluate(baseCommand, argument)) i += SkipScope(script, i);
                            else scopeDepth++;
                            break;
                        //Else
                        case "else":
                            if (Evaluate(baseCommand, argument)) i += SkipScope(script, i);
                            else scopeDepth++;
                            break;

                        //Choice
                        case "choice":
                            string[] choiceLines = ReadScope(script, i);
                            i += choiceLines.Length + 2; //{ and } not included

                            Game.eventChoiceDescriptions = new List<string>();
                            Game.eventChoiceResults = new List<string>();
                            for (int ii = 0; ii < choiceLines.Length; ii++)
                            {
                                string[] choiceSplit = choiceLines[ii].Split(new string[] { "->" }, StringSplitOptions.None);
                                if (choiceSplit.Length > 1)
                                {
                                    Game.eventChoiceDescriptions.Add(Utils.RBQ(choiceSplit[0]));
                                    Game.eventChoiceResults.Add(Utils.RBQ(choiceSplit[1]));
                                }
                            }
                            ui.DisplayEventChoices(Game.eventChoiceDescriptions);
                            Game.gameState = Game.GameState.EventChoice;
                            break;
                    }
                }
            }
        }

        public static bool Evaluate(string baseCommand, string argument, bool addToStack = true)
        {
            bool result = false;

            if (baseCommand != "else" && scopeDepth == 0) evaluationStack.Clear();

            switch (baseCommand)
            {
                case "hasequipment":
                    for (int i = 0; i < Game.player.inventory.Count; i++)
                    {
                        if (Game.player.inventory[i].name == argument)
                        {
                            if (Game.player.inventory[i].equipped) result = true;
                        }
                    }
                    break;
                case "hasflag": result = Game.GetFlag(argument); break;
                case "hasskill": result = Game.player.mutations.ContainsKey(argument); break;
                case "notflag": result = !(Game.GetFlag(argument)); break;
                case "notskill": result = !(Game.player.mutations.ContainsKey(argument)); break;
                case "else": result = GetLatestEvaluation(); break;
            }

            if (addToStack) evaluationStack.Add(result);
            return result;
        }

        private static bool GetLatestEvaluation()
        {
            if (evaluationStack.Count < 1) return false;
            return evaluationStack[scopeDepth];
        }

        private static int SkipScope(string[] script, int startingPosition)
        {
            int internalScopeDepth = 0;
            string currentLine = "";
            int linesSkipped = 2; //Skip initial statement and {
            while (currentLine != "}")
            {
                currentLine = script[startingPosition + linesSkipped];

                if (currentLine == "{") internalScopeDepth++;
                if (currentLine == "}" && internalScopeDepth > 0) { internalScopeDepth--; currentLine = ""; }

                linesSkipped++;
            }

            return linesSkipped - 1;
        }

        //Used only for choices
        private static string[] ReadScope(string[] script, int startingPosition)
        {
            List<string> scope = new List<string>();
            string currentLine = "";
            int linesSkipped = 2; //Skip initial declaration and {
            while (currentLine != "}")
            {
                currentLine = script[startingPosition + linesSkipped];
                if (currentLine != "}") scope.Add(currentLine);
                linesSkipped++;
            }

            return scope.ToArray();
        }

        private static int ParseEnemy(string[] script, int startingPosition)
        {
            bool done = false;
            int counter = 0;
            while (!done)
            {
                string currentLine = script[startingPosition + counter];
                string[] split = currentLine.Split(new string[] { " " }, StringSplitOptions.RemoveEmptyEntries);
                if (split.Length > 0)
                {
                    string baseCommand = split[0];
                    string argument = Utils.RBQ(currentLine);

                    switch (baseCommand)
                    {
                        case "}": done = true; break;
                        case "defense": definingEnemy.defense = Convert.ToInt32(argument); break;
                        case "dodgechance": definingEnemy.dodgeChance = Convert.ToInt32(argument); break;
                        case "experience": definingEnemy.experience = Convert.ToInt32(argument); break;
                        case "health": definingEnemy.health = Convert.ToInt32(argument); break;
                        case "maxhealth": definingEnemy.maxHealth = Convert.ToInt32(argument); break;
                        case "name": definingEnemy.name = argument; break;
                        case "strength": definingEnemy.strength = Convert.ToInt32(argument); break;

                        case "attacks":
                            definingEnemy.attacks = new List<string>();
                            counter++; //Skip 'attacks'
                            string attackName = "";
                            while (!attackName.Contains("}"))
                            {
                                counter++; //Skip the initial {, then iterate over lines
                                attackName = script[startingPosition + counter];
                                if (attackName != "}") definingEnemy.attacks.Add(attackName);
                            }
                            break;

                        case "inventory":
                            definingEnemy.inventory = new List<Item>();
                            counter++; //Skip 'inventory'
                            string itemName = "";
                            while (!itemName.Contains("}"))
                            {
                                counter++; //Skip the initial {, then iterate over lines
                                itemName = script[startingPosition + counter];
                                if (itemName != "}") definingEnemy.inventory.Add(new Item(itemName));
                            }
                            break;
                    }
                }

                counter++;
            }

            return counter;
        }
    }
}