A different approach to work on the Text101 challenge from Udemy Unity Course

cell scene.txt

"cell"	"You are on a cell."
"sheets_0"	"These are some pretty dirt sheets... Did you really sleep on these...?"
"mirror"	"You see a broken mirror on the floor..."
"lock_0"	"A locked door. It feels pretty much close for me."
"sheets_1"	"Awesome, more dirty sheets. I think I have a teammate, but I can't really remember."
"cell_mirror"	"Okay... what should I do with this? I will just put it on my pocket."
"lock_1"	"Another lock, great... I think there is something different on this one."
"freedom"	"Nice! The locker was broken, I'm out of this dirty cell."

cell > sheets_0	('S'; "Sheets")
sheets_0 > cell	('R'; "Return")
cell > mirror	('M'; "Mirror")
mirror > cell	('R'; "Return")
cell > lock_0	('L'; "Lock")
lock_0 > cell	('R'; "Return")
mirror > cell_mirror	('T'; "Take")
cell_mirror > sheets_1	('S'; "Sheets")
sheets_1 > cell_mirror	('R'; "Return")
cell_mirror > lock_1	('L'; "Lock")
lock_1 > cell_mirror	('R'; "Return")
lock_1 > freedom	('O'; "Open")

start: cell
end: freedom

corridor scene.txt

"corridor"	"You find yourself in a creepy corridor..."
"stairs_0"	"Right, nothing in here, not even a single lightbulb."
"floor"	"There is something weird on the floor, should I get it?"
"closet_door"	"A closet! Oh wait... it is locked."
"stairs_1"	"More stairs? Oh my... nothing in here."
"corridor_1"	"Okay, it is a <i>hairclip</i>. What should I do with this?"
"in_closet"	"Wait... I can use the hairclip to open this closet! There is an office uniform inside!"
"stairs_2"	"Nothing in here."
"corridor_2"	"What should I do next? I have to get outta here."
"corridor_3"	"A lot of officers in here, I need to get out without being noticed."
"courtyard"	"I'm out!"

corridor > stairs_0	('S'; "Climb stairs")
stairs_0 > corridor	('R'; "Return")
corridor > floor	('F'; "Look at the floor")
floor > corridor	('R'; "Go back")
corridor > closet_door	('C'; "Open closet door")
closet_door > corridor	('R'; "Return")
floor > corridor_1	('H'; "Hairclip")
corridor_1 > in_closet	('P'; "Pick")
corridor_1 > stairs_1	('S'; "Climb stairs")
stairs_1 > corridor_1	('R'; "Return")
in_closet > corridor_3	('D'; "Dress uniform")
corridor_3 > in_closet	('U'; "Take out the uniform")
in_closet > corridor_2	('R'; "Return to corridor")
corridor_2 > in_closet	('B'; "Go back")
corridor_2 > stairs_2	('R'; "Climb stairs")
stairs_2 > corridor_2	('B'; "Go back")
corridor_3 > courtyard	('S'; "Go to the courtyard")

start: corridor
end: courtyard

MapScript.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class World
{
    LinkedList<Map> map_list;
    Map curr_map;

    public World()
    {
        map_list = new LinkedList<Map>();

        Map cell = new Map("Cell Scene");
        map_list.AddLast(cell);

        Map corridor = new Map("Corridor Scene");
        map_list.AddLast(corridor);

        SetStart(cell);
        SetEnd(corridor);
        SetCurrentMap(cell);
    }

    public void SetCurrentMap(Map m)
    {
        curr_map = m;
    }

    public Map CurrentMap()
    {
        return curr_map;
    }

    public void SetStart(Map m)
    {
        if (map_list.Contains(m))
            map_list.Remove(m);
        map_list.AddFirst(m);
    }

    public Map StartMap()
    {
        return map_list.First.Value;
    }

    public bool IsStart(Map m)
    {
        if (m.Equals(StartMap()))
            return true;
        else return false;
    }

    public void SetEnd(Map m)
    {
        if (map_list.Contains(m))
            map_list.Remove(m);
        map_list.AddLast(m);
    }

    public Map EndMap()
    {
        return map_list.Last.Value;
    }

    public bool IsEnd(Map m)
    {
        if (m.Equals(EndMap()))
            return true;
        else return false;
    }

    public Map NextMap()
    {
        curr_map = map_list.Find(curr_map).Next.Value;
        return curr_map;
    }

    public bool HasEnded()
    {
        if (curr_map.Equals(map_list.Last.Value))
            return true;
        else return false;
    }
}

public class Map
{
    private Graph states;
    public string map_name;

    public Map(string name)
    {
        this.map_name = name;
        states = new Graph();
        ReadMapFile();
    }

    private void ReadMapFile()
    {
        string line;
        System.IO.StreamReader file = new System.IO.StreamReader(@"D:\Users\User\Documents\Text101\Assets\maps\" + map_name.ToLower() + ".txt");

        while ((line = file.ReadLine()) != "")
            ReadVertex(line);
            
        while ((line = file.ReadLine()) != "")
            ReadEdge(line);

        while ((line = file.ReadLine()) != null)
            ReadSettings(line);
    }

    private void ReadVertex(string line)
    {
        string from = line.Split('\t')[0].Replace("\"", "").Trim();
        string to = line.Split('\t')[1].Replace("\"", "").Trim();
        this.AddState(from, to);
    }

    private void ReadEdge(string line)
    {
        string[] vertex_rel = line.Split('\t')[0].Split('>');
        string[] edge_info = line.Split('\t')[1].Split(';');
        char edge_action = edge_info[0].Replace("'", "").Replace("(", "").ToCharArray()[0];
        string edge_action_name = edge_info[1].Replace("\"", "").Replace(")", "").Trim() ;
        Vertex from = states.Find(vertex_rel[0].Trim());
        Vertex to = states.Find(vertex_rel[1].Trim());
        if (from != null && to != null)
            this.Link(edge_action, edge_action_name, from, to);
        else
            throw new System.ArgumentException("Invalid input file for " + map_name + ". Please review the Vertex/Edges.");
    }

    private void ReadSettings(string line)
    {
        string command = line.Split(':')[0];
        string vertex = line.Split(':')[1].Trim();

        if (command.Equals("start"))
            this.SetStart(states.Find(vertex));
        if (command.Equals("end"))
            this.SetEnd(states.Find(vertex));
    }

    public Vertex AddState(string name, string msg)
    {
        Vertex v = states.Insert(name, msg);
        return v;
    }

    public void Link(char action, string action_name, Vertex v, Vertex y)
    {
        states.Link(action, action_name, v, y);
    }

    public void SetStart(Vertex v)
    {
        states.SetStart(v);
    }

    public Vertex StartPoint()
    {
        return states.GetStart();
    }

    public bool IsStart(Vertex v)
    {
        if (v.Equals(StartPoint()))
            return true;
        else return false;
    }

    public void SetEnd(Vertex v)
    {
        states.SetEnd(v);
    }

    public Vertex EndPoint()
    {
        return states.GetEnd();
    }

    public bool IsEnd(Vertex v)
    {
        if (v.Equals(EndPoint()))
            return true;
        else return false;
    }

}

public class Graph
{
    LinkedList<Vertex> vertex_list;

    internal Graph()
    {
        vertex_list = new LinkedList<Vertex>();
    }

    public Vertex Insert(string name, string msg)
    {
        Vertex v = new Vertex(name, msg);
        vertex_list.AddLast(v);
        return v;
    }

    public Vertex Find(string vertex_name)
    {
        foreach (Vertex v in vertex_list)
        {
            if (vertex_name.Equals(v.name))
                return v;
        }
            
        return null;
    }

    public Edge Link(char action, string action_name, Vertex v1, Vertex v2)
    {
        Edge link = new Edge(action, action_name, v1, v2);
        v1.AddNeighbor(link);
        return link;
    }

    public int Size()
    {
        return vertex_list.Count;
    }

    public void SetStart(Vertex v)
    {
        if (vertex_list.Contains(v))
            vertex_list.Remove(v);
        vertex_list.AddFirst(v);
    }

    public Vertex GetStart()
    {
        return vertex_list.First.Value;
    }

    public void SetEnd(Vertex v)
    {
        if (vertex_list.Contains(v))
            vertex_list.Remove(v);
        vertex_list.AddLast(v);
    }

    public Vertex GetEnd()
    {
        return vertex_list.Last.Value;
    }
}

public class Vertex {

    public string name;
    public string msg;
    private LinkedList<Edge> neighbors;

    internal Vertex(string name, string msg)
    {
        this.name = name;
        this.msg = msg;
        this.neighbors = new LinkedList<Edge>();
    }

    public void AddNeighbor(Edge e)
    {
        neighbors.AddLast(e);
    }

    public LinkedList<Edge> Neighbors()
    {
        return neighbors;
    }

}

public class Edge {
    private Vertex node1;
    private Vertex node2;
    public char action;
    public string action_name;

    internal Edge(char action, string action_name, Vertex node1, Vertex node2)
    {
        this.action = action;
        this.action_name = action_name;
        this.node1 = node1;
        this.node2 = node2;
    }

    public Vertex CurrentVertex()
    {
        return node1;
    }

    public Vertex RelatedVertex()
    {
        return node2;
    }
}

TextController.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;

public class TextController : MonoBehaviour {

    public Text text;
    Vertex curr_state;
    Map map;
    World world;

    // Use this for initialization
    void Start () {
        world = new World();
        map = world.CurrentMap();
        curr_state = map.StartPoint();
        text.text = Message(curr_state);
    }
	
	// Update is called once per frame
	void Update () {

        if (world.HasEnded() && map.IsEnd(curr_state))
        {
            text.text = "THE END";
        } else if (map.IsEnd(curr_state))
        {
            map = world.NextMap();
            curr_state = map.StartPoint();
            text.text = Message(curr_state);
        }
        else
        {
            foreach (Edge element in curr_state.Neighbors())
                if (Input.inputString.ToUpper() == element.action.ToString())
                {
                    curr_state = element.RelatedVertex();
                    text.text = Message(curr_state);
                }
        }

        
    }

    string Message (Vertex state)
    {
        string msg = state.msg + "\n\n";

        if (state.Neighbors().Count > 0)
            msg += "Press ";

        foreach (Edge element in state.Neighbors())
            msg += "<b>" + element.action + "</b> for <i>" + element.action_name + "</i>. ";

        return msg;
    }

}