Answer to RStudio Portfolio Advanced Question

03_shiny_dashboard.Rmd

---
title: "Stock Analysis"
output: 
  flexdashboard::flex_dashboard:
    orientation: columns
    vertical_layout: fill
runtime: shiny
---

```{r setup, include=FALSE}
library(flexdashboard)
library(tidyverse)
library(tidyquant)
library(timetk)
library(highcharter)
library(DT)
```

Inputs {.sidebar}
-----------------------------------------------------------------------
```{r}
textInput('ticker', 'Enter Stock Ticker Symbol', 'GOOG')
selectInput(
  'func', 
  'Select Metric of Interest',
  choices = list('Volatility' = 'var', 'Average' = 'mean')
)
price <- reactive({tq_get(input$ticker, from = "2018-01-01") %>% 
  mutate(change = close - open)})
```

Column {data-width=500}
-----------------------------------------------------------------------

### Stock Price Over Time (Chart)

```{r}
renderHighchart({
  xts_price <- tk_xts(price())
  colnames(xts_price) <- paste0(input$ticker,'.', colnames(xts_price))

  highchart(type = "stock") %>% 
    hc_add_series(xts_price, type = "candlestick")
})
```


Column {data-width=500}
-----------------------------------------------------------------------

### Stock Metric

```{r}
renderValueBox({
  volatility <- price() %>% 
    select(date, adjusted) %>% 
    mutate(returns = (log(adjusted) - log(lag(adjusted)))) %>%
    na.omit() %>% 
    summarize(volatility = eval(parse(text = paste0(input$func, "(returns)")))) %>% 
    pull(volatility)
  
  valueBox(
    sprintf('%g%%', round(volatility*100,2)),
    input$func,
    icon = 'ion-cash'
  )
})

```

### Stock Price Table

```{r}
DT::renderDataTable({
  DT::datatable(price(), rownames = FALSE, options = list(order = list(list(0, 'desc')))) %>% 
    formatCurrency(c('open', 'high', 'low', 'close', 'adjusted', 'change')) %>% 
    formatDate(c('date')) %>%
    formatStyle('volume', 
      background = styleColorBar(price()$volume, 'steelblue')
    ) %>% 
    formatStyle(
      'change', 
      color = styleInterval(c(0), c('maroon', 'darkgreen'))
    )  
})

```