library(tidyverse)
library(tidyquant)

#XAU/USD | Gold Spot US Dollar Price
df_xau <- 
  df_xau <- 
  read_csv("data/xau.csv") %>% 
  janitor::clean_names() %>% 
  mutate(date = parse_date(date, "%m/%d/%Y")) %>% 
  select(date, xau = price)

#XAG/USD | Silver Spot US Dollar Price
df_xag <- 
  df_xag <- 
  read_csv("data/xag.csv") %>% 
  janitor::clean_names() %>% 
  mutate(date = parse_date(date, "%m/%d/%Y")) %>% 
  select(date, xag = price)

#Merging the datasets
df_merged <- 
  df_xau %>% 
  left_join(df_xag) %>% 
  drop_na()


#Index data (Range:0-100)
library(recipes)

df_index <- 
  df_merged %>% 
  recipe(~ .) %>% 
  step_range(all_numeric(), 
             min = 0, 
             max = 100) %>% 
  prep() %>% 
  bake(new_data = NULL) %>% 
  pivot_longer(-date) 

#Plot
df_index %>% 
  ggplot(aes(date, value, col = name)) +
  geom_line(linewidth = 2, aes(group = name)) +
  geom_point(aes(group = name), size = 5) +
  ggrepel::geom_text_repel(
    data = df_index %>% group_by(name) %>% slice_head(n = 1),
    aes(label = round(value,0)),
    hjust = 1, 
    vjust = 1,
    nudge_x = 0.5,
    fontface = "bold", 
    family = "Roboto Slab",
    size = 6,
    segment.color = NA
  ) +
  ggbraid::geom_braid(
    data = df_index %>% pivot_wider(), 
    aes(
      y = NULL, ## Overwrite the inherited aes from ggplot()
      col = NULL, 
      ymin = xag, 
      ymax = xau, 
      fill = xag < xau
    ), 
    alpha = 0.3
  ) +
  scale_color_manual(values = c("xau" = "gold", 
                                "xag" = "darkgray")) +
  scale_fill_manual(values = c("TRUE" = "gold", 
                               "FALSE" = "darkgray")) +
  scale_x_date(expand = expansion(mult = c(.1, .15))) +
  labs(
    x = element_blank(), 
    y = element_blank(),
    subtitle = "Normalized to 1-100",
    title = "<span style = 'color:gold;'>XAU/USD | Gold Spot US Dollar Price</span><br><span style = 'color:darkgray;'>XAG/USD | Silver Spot US Dollar Price</span>"
  ) +
  theme_minimal(base_family = "Roboto Slab", base_size = 18) +
  theme(
    panel.grid = element_blank(),
    panel.grid.major.x = element_line(linetype = "dashed", color = "gray"),
    panel.grid.major.y = element_line(linetype = "dashed", color = "gray"),
    plot.subtitle = ggtext::element_markdown(face = "bold"),
    plot.title = ggtext::element_markdown(face = "bold"),
    axis.text = element_text(face = "bold"),
    plot.background = element_rect(fill = "azure", color = "azure"),
    legend.position = "none")