Geomtric/Brownian Motion plotting helper function

[spsanderson]

Create a helper function to plot out the geometric/brownian motion augment functions.

Function:

ts_brownian_motion_plot <- function(.data, .date_col, .value_col, 
                                    .interactive = FALSE){
    
    # Tidyeval ---
    plotly_plot <- as.logical(.interactive)
    date_var_expr <- rlang::enquo(.date_col)
    value_var_expr <- rlang::enquo(.value_col)
    
    # Attributes
    atb <- attributes(.data)
    
    # Checks ---
    if (!is.data.frame(.data)){
        rlang::abort(
            message = "'.data' must be either a data.frame/tibble.",
            use_cli_format = TRUE
        )
    }
    
    if (!is.logical(.interactive)){
        rlang::abort(
            message = "'.interactive' must be a logical of TRUE/FALSE.",
            use_cli_format = TRUE
        )
    }
    
    if (!".motion_type" %in% names(atb)){
        rlang::abort(
            message = "The '.data' must come from a ts_brownian or ts_geometric
            function."
        )
    }
    
    # Data Manipulation ---
    df <- dplyr::as_tibble(.data)
    
    # Graph ---
    g <- df %>%
        ggplot2::ggplot(ggplot2::aes(x = {{ date_var_expr }}, y = {{ value_var_expr }},
                                     group = sim_number, color = sim_number)) +
        ggplot2::geom_line() +
        ggplot2::theme_minimal() +
        ggplot2::labs(
            title = atb$.motion_type,
            subtitle = paste0("Simulations: ", atb$.num_sims, 
                              " - Initial Value: ", round(atb$.initial_value, 2),
                              " - Delta Time: ", round(atb$.delta_time, 2))
        ) +
        ggplot2::theme(legend.position = if(atb$.num_sims > 9) {"none"})
    
    # Return ---
    if (plotly_plot){
        g <- plotly::ggplotly(g)
    }
    
    return(g)
    
}

Example:

library(healthyR.ts)
library(tidyverse)

df <- ts_to_tbl(AirPassengers) %>% select(-index)

augmented_data <- df %>%
    ts_brownian_motion_augment(
        .date_col = date_col,
        .value_col = value, 
        .time = 144
    ) 

augmented_data %>%
    ts_brownian_motion_plot(.date_col = date_col, .value_col = value)