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

namespace SnakeRPG
{
    public class Command
    {
        public string command = "";
        public string[] parameters = null;
    }

    public static partial class Main
    {
        public static bool HandleScript(string[] script, Entity source = null, Entity trigger = null)
        {
            bool toReturn = false;
            bool lastConditionMet = false;

            if (script != null)
            {
                for (int i = 0; i < script.Length; i++)
                {
                    string line = ApplyMacros(script[i], source, trigger);
                    Command command = ReadCommand(line);

                    switch (command.command)
                    {
                        case "attack":
                            Attack(snake, source);
                            break;
                        case "block":
                            toReturn = true;
                            break;
                        case "changeimage":
                            source.sprite.currentImage = Convert.ToInt32(command.parameters[0]);
                            break;
                        case "die":
                            source.Die();
                            break;
                        case "else":
                            if (lastConditionMet)
                            {
                                i += 2; //Own line + {
                                int depth = 1;
                                while (depth > 0)
                                {
                                    Command checkForClose = ReadCommand(script[i]);
                                    if (checkForClose.command == "{") depth++;
                                    if (checkForClose.command == "}") depth--;
                                    if (depth > 0) i++;
                                }
                            }
                            break;
                        case "freeze":
                            movementFreeze = (float)Convert.ToInt32(command.parameters[0]) / 1000f;
                            break;
                        case "fullheal":
                            snake.health = snake.maxHealth;
                            break;
                        case "gaingold":
                            snake.gold += Convert.ToInt32(command.parameters[0]);
                            break;
                        case "if":
                            bool conditionMet = EvaluateStatement(command.parameters[0], source, trigger);
                            lastConditionMet = conditionMet;

                            if (!conditionMet)
                            {
                                i += 2; //Own line + {
                                int depth = 1;
                                while (depth > 0)
                                {
                                    Command checkForClose = ReadCommand(script[i]);
                                    if (checkForClose.command == "{") depth++;
                                    if (checkForClose.command == "}") depth--;
                                    if (depth > 0) i++;
                                }
                            }
                            break;
                        case "hit":
                            if (command.parameters[0] == "player")
                            {
                                Main.Attack(source, snake);
                            }
                            break;
                        case "hitself":
                            Main.Attack(snake, snake);
                            break;
                        case "instantdeath":
                            Main.PlayerDies();
                            break;
                        case "message":
                            Main.Message(command.parameters[0]);
                            break;
                        case "percentualdamage":
                            float percentage = Convert.ToSingle(command.parameters[0]);
                            snake.ReceiveDamage(Convert.ToInt32(Math.Ceiling((float)snake.maxHealth * (percentage / 100f))));
                            break;
                        case "randommove":
                            int relX = Entity.random.Next(-1, 2);
                            int relY = Entity.random.Next(-1, 2);
                            int targetX = source.x + relX;
                            int targetY = source.y + relY;
                            if (targetX > 0 && targetX < MAP_WIDTH - 1 && targetY > 0 && targetY < MAP_HEIGHT - 1)
                            {
                                if (GetEntityAtLocation(targetX, targetY) == null)
                                {
                                    source.SetPosition(targetX, targetY);
                                }
                            }
                            break;
                        case "setspawnpoint":
                            LogVerbose("Spawn point set!");
                            spawnMap = map.filename;
                            spawnX = source.x;
                            spawnY = source.y;
                            spawnDirection = trigger.direction;
                            break;
                        case "sound":
                            Audio.Play(command.parameters[0]);
                            break;
                        case "upgradehealth":
                            if (upgradePoints < 1)
                            {
                                Message("You need upgrade points to upgrade.");
                            }
                            else
                            {
                                Audio.Play("powerup");
                                upgradePoints--;
                                snake.maxHealth += 25;
                                snake.health += 25;
                                Message("Health upgraded!");
                            }
                            break;
                        case "upgradespeed":
                            if (upgradePoints < 1)
                            {
                                Message("You need upgrade points to upgrade.");
                            }
                            else
                            {
                                Audio.Play("powerup");
                                upgradePoints--;
                                snake.speed += 1.0f;
                                Message("Speed upgraded!");
                            }
                            break;
                        case "upgradestrength":
                            if (upgradePoints < 1)
                            {
                                Message("You need upgrade points to upgrade.");
                            }
                            else
                            {
                                Audio.Play("powerup");
                                upgradePoints--;
                                snake.strength += 7;
                                Message("Strength upgraded!");
                            }
                            break;
                    }
                }
            }

            return toReturn;
        }

        static Command ReadCommand(string source)
        {
            Command toReturn = new Command();

            //Remove comments
            if (source.Length > 1)
            {
                for (int i = 0; i < source.Length - 2; i++)
                {
                    string twoChars = source.Substring(i, 2);
                    if (twoChars == "//")
                    {
                        source = source.Substring(0, i);
                        i = source.Length - 2; //End for loop
                    }
                }
            }

            //Remove leading spaces
            bool leadingSpacesPresent = true;
            while (leadingSpacesPresent)
            {
                leadingSpacesPresent = false;
                if (source.StartsWith(" ") || source.StartsWith("   "))
                {
                    leadingSpacesPresent = true;
                    source = source.Substring(1);
                }
            }

            //Remove trailing spaces
            bool trailingSpacesPresent = true;
            while (trailingSpacesPresent)
            {
                trailingSpacesPresent = false;
                if (source.EndsWith(" ") || source.EndsWith("   "))
                {
                    trailingSpacesPresent = true;
                    source = source.Substring(0, source.Length - 1);
                }
            }

            if (!source.Contains("("))
            {
                toReturn.command = source;
            }
            else
            {
                toReturn.command = source.Substring(0, source.IndexOf("("));

                StringBuilder stringBuilder = new StringBuilder();
                List<string> parameters = new List<string>();
                int stringIndex = source.IndexOf("(") + 1;
                bool reading = true;
                bool readingString = false;
                int depth = 1;
                while (reading)
                {
                    bool keepReading = true;
                    string character = source.Substring(stringIndex, 1);

                    if (depth == 1)
                    {
                        if ((character == ")" || character == ",") && !readingString) //Parse parameter
                        {
                            keepReading = false;
                            string toAdd = stringBuilder.ToString();
                            toAdd = toAdd.Replace("\"", ""); //Strip quotation marks
                            parameters.Add(toAdd);
                            stringBuilder.Clear();

                            if (character == ")") //Stop parsing
                            {
                                reading = false;
                            }
                        }
                    }

                    if (keepReading)
                    {
                        if (character == "(" && !readingString) depth++;
                        if (character == ")" && !readingString) depth--;
                        stringBuilder.Append(character);
                        if (character == "\"") readingString = !readingString;
                    }
                    stringIndex++;
                }

                toReturn.parameters = parameters.ToArray();
            }

            return toReturn;
        }

        public static bool EvaluateStatement(string statement, Entity source = null, Entity trigger = null)
        {
            string baseStatement = statement;
            string parameter = "";
            if (statement.Contains("("))
            {
                baseStatement = statement.Substring(0, statement.IndexOf("("));
                int startPos = statement.IndexOf("(") + 1;
                parameter = statement.Substring(startPos, statement.LastIndexOf(")") - startPos);
            }
            switch (baseStatement) //Best if implementation ever
            {
                case "notwallhack":
                    return !wallhack;
                case "paymoney":
                    int amount = Convert.ToInt32(parameter);
                    if (snake.gold < amount) return false;
                    else { snake.gold -= amount; return true; }
                case "playerpresent":
                    int distance = Math.Abs(source.x - snake.x) + Math.Abs(source.y - snake.y);
                    for (int i = 0; i < snake.tail.Count; i++)
                    {
                        int newDistance = Math.Abs(source.x - snake.tail[i].x) + Math.Abs(source.y - snake.tail[i].y);
                        if (newDistance < distance) distance = newDistance;
                    }
                    if (distance < 2) return true;
                    break;
            }

            return false;
        }

        public static string ApplyMacros(string line, Entity source = null, Entity trigger = null)
        {
            line = line.Replace("$PARAMETER_STRING$", source.parameterString);
            line = line.Replace("$PARAMETER_INT$", Convert.ToString(source.parameterInt));
            return line;
        }
    }
}