#include "std_lib_inc.h"

// A program which allows you to wander across a maze using 'w','a','s' and 'd'.

const vector<vector<char>> kMaze = {
    // kMaze[y][x]
    {'#', '.', '.', '.', '.'},
    {'#', '.', '#', '.', '.'},
    {'.', 'Z', '#', '.', '.'},
    {'.', '#', '#', '#', '.'},
    {'.', '.', '.', '.', '.'}
    // ^ player starts here (4,0)
};

const vector<int> kPlayerStartPosition = {4,0};

/* legend
 * S - player
 * Z - goal
 * . - empty space
 * # - wall
 */

/// Use inputs to move the player. Don't move the player, if move is illegal
/// @param player_pos The current player position
/// @param move_vector The requested move vector
/// @return The new position of the player
vector<int> move_player(vector<int> player_pos, vector<int> move_vector);

/// Check if a certain space can be moved to
/// @param target The position to check
/// @return If the position can be moved to
bool is_pos_free(vector<int> target);

/// Check if a certain space can be moved to
/// @param player_pos The current player position
void render_play_field(vector<int> player_pos);

int main()
{
    // Create player position formatted as (y, x)
    vector<int> player_pos = kPlayerStartPosition;

    // Create input variable
    char input;

    // Run the game loop
    while (true)
    {
        // Render the play field
        render_play_field(player_pos);

        // Check if the goal has been reached yet
        if (kMaze[player_pos[0]][player_pos[1]] == 'Z')
        {
            // Goal reached! Let's celebrate!
            cout << "Ziel erreicht! Herzlichen Glueckwunsch!\n";
            break;
        }

        // Get input
        cin >> input;

        // Create an empty vector to store the requested movement in
        vector<int> target_movement_vector = {0, 0};

        // Check what the player wants to do. Store the requested movement in the vector
        // print messages to screen if help was requested or an unknown input was entered
        switch (input)
        {
        case 'w':
            target_movement_vector = {-1, 0};
            break;
        case 'a':
            target_movement_vector = {0, -1};
            break;
        case 's':
            target_movement_vector = {1, 0};
            break;
        case 'd':
            target_movement_vector = {0, 1};
            break;
        case 'h':
            // Print help text to console
            cout << "Gebe 'w', 'a', 's', oder 'd' ein zum bewegen. Gebe 'h' ein um diesen Text anzuzeigen.\n";
            break;
        default:
            // Target action not recognized. Print 'error' message to screen
            cout << "Diese Eingabe kenne ich nicht. Gib 'h' ein, um eine Hilfe zu erhalten.\n";
            break;
        }

        // Check & apply the requested movement
        player_pos = move_player(player_pos, target_movement_vector);
    }
    // End the program
    return 0;
}

vector<int> move_player(vector<int> player_pos, vector<int> move_vector)
{
    // Calculate the position the player wants to move to
    const vector<int> target_position = { player_pos[0] + move_vector[0], player_pos[1] + move_vector[1] };

    // Move player to requested position in case position is free
    if (is_pos_free(target_position))
    {
        player_pos[0] += move_vector[0];
        player_pos[1] += move_vector[1];
    }
    else
        cout << "Bewegung nicht moeglich!\n";

    // Return the player position
    return player_pos;
}

bool is_pos_free(vector<int> target)
{
    if (target[1] < 0 || target[0] < 0 || target[1] > kMaze.size() - 1 || target[0] > kMaze[target[1]].size() - 1)
        return false; // Target pos out of bounds of area
    if (kMaze[target[0]][target[1]] == '#')
        return false; // Target pos is a wall
    return true; // Target pos is movable to (is not wall and not out of bounds)
}

void render_play_field(const vector<int> player_pos)
{
    for (int i = 0; i < kMaze.size(); ++i)
    {
        // For every row...
        for (int j = 0; j < kMaze[i].size(); ++j)
        {
            // ... render ...
            if (i == player_pos[0] && j == player_pos[1])
                cout << "S"; // ... 'S' if it is the entry where the player is currently
            else
                cout << kMaze[i][j]; // ... the actual entry of the field
            cout << " "; // Add space between entries
        }
        cout << "\n"; // Finish the row by ending the actively drawn line
    }
}