#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>> play_field = {
    // playspace[y][x]
    {'#', '.', '.', '.', '.'},
    {'#', '.', '#', '.', '.'},
    {'.', 'Z', '#', '.', '.'},
    {'.', '#', '#', '#', '.'},
    {'.', '.', '.', '.', '.'}
    // ^ player starts here (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
vector<int> move_player(vector<int> player_pos, char input);

/// Check if the player could be moved to a certain space
bool can_move_player(vector<int> player_pos, int move_x, int move_y);

/// Check if a certain space can be moved to
bool is_pos_free(int x, int y);

/// Render the current playfield to the console
void render_play_field(vector<int> player_pos);

int main()
{
    // Create player position formatted as (y, x)
    vector<int> player_pos = {4, 0};

    // Create input variable
    char input;

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

        // Get input
        cin >> input;
        // Vaildate input
        if (!cin)
        {
            cout << "Diese Eingabe kenne ich nicht. Gib 'h' ein, um eine Hilfe zu erhalten.\n";
            continue;
        }

        // move player based on inputs, don't move player, if move would be illegal
        player_pos = move_player(player_pos, input);

        // Check if the goal has been reached yet
        if (play_field[player_pos[0]][player_pos[1]] == 'Z')
        {
            // Render the play field one last time to display the completed maze
            render_play_field(player_pos);

            // Goal reached! Let's celebrate!
            cout << "Ziel erreicht! Herzlichen Glueckwunsch!\n";
            break;
        }
    }
    // End the program
    return 0;
}

vector<int> move_player(vector<int> player_pos, char input)
{
    switch (input)
    {
    case 'w':
        // Check if it is possible to move player to target pos
        if (can_move_player(player_pos, 0, -1))
            --player_pos[0];
        break;
    case 'a':
        // Check if it is possible to move player to target pos
        if (can_move_player(player_pos, -1, 0))
            --player_pos[1];
    // Actually move player
        break;
    case 's':
        // Check if it is possible to move player to target pos
        if (can_move_player(player_pos, 0, 1))
            ++player_pos[0];
        break;
    case 'd':
        // Check if it is possible to move player to target pos
        if (can_move_player(player_pos, 1, 0))
            ++player_pos[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;
    }
    return player_pos;
}

bool can_move_player(const vector<int> player_pos, const int move_x, const int move_y)
{
    // Calculate the position we want to be at
    const int target_x = player_pos[1] + move_x;
    const int target_y = player_pos[0] + move_y;

    // Check if the position can be moved to
    const bool result = is_pos_free(target_x, target_y);
    if (!result) // Complain if not
        cout << "Bewegung nicht moeglich!\n";
    return result; // Return result
}

bool is_pos_free(const int x, const int y)
{
    if (x < 0 || y < 0 || x > 4 || y > 4)
        return false; // Target pos out of bounds of area
    if (play_field[y][x] == '#')
        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 < play_field.size(); ++i)
    {
        // For every row...
        for (int j = 0; j < play_field[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 << play_field[i][j]; // ... the actual entry of the field
        }
        cout << "\n"; // Finish the row by ending the actively drawn line
    }
}