library(openair)
library(tidyverse)
library(lubridate)
library(gganimate)

jhn <- as_tibble(importSAQN(site = "REN02", year = 2017:2019, pollutant = "all")) %>%
  mutate(day = date(date))
# saveRDS(jhn, "jhn.rds")
# jhn <- readRDS("jhn.rds")

pm2.5_size = 1.5 # smallest dot size

p <- jhn %>%
  # filter(date >= dmy("01-01-2019"), date < dmy("01-02-2019")) %>%
  ggplot(aes(x = date)) +
  ylim(0, 100) +
  ylab("") +
  xlab("") +
  scale_x_datetime(date_breaks = "1 day", breaks = NULL) + # this and view_follow fix the range
  labs(title = "{format(frame_time, '%B %d %Y')}") +
  geom_smooth(colour="black", alpha = 1, aes(y = pm10)) +
  geom_smooth(colour="blue", alpha = 1, aes(y = pm2.5)) +
  geom_point(colour="black", alpha = .3, aes(y = pm10), size = 4*pm2.5_size) +
  geom_point(colour="blue", alpha = .3, aes(y = pm2.5), size = pm2.5_size) +
  theme_minimal() +
  theme(axis.text.x = element_blank(), panel.grid.major.x = element_blank(), panel.grid.minor.x = element_blank()) +
  # gganimate
  transition_time(day) +
  enter_fade() +
  exit_fade() +
  ease_aes("linear") +
  view_follow(fixed_y = TRUE)

# output as animated gif
scale = .5
animate(p, width = 1920*scale, height = 1080*scale,
        fps = 24, duration = 60)
anim_save("anim.gif")

# output as video
scale = 1
animate(p, width = 1920*scale, height = 1080*scale,
        fps = 24, duration = 60, renderer = ffmpeg_renderer())
anim_save("anim.mp4")