library(sf)
library(animation)

#
# Load data
#

# State boundaries
statefp <- "data/cb_states/cb_2022_us_state_20m.shp"
statebnds <- st_read(statefp)

# Conterminous United States
inconterm <- !(statebnds$STUSPS %in% c("AK", "HI", "PR"))
conterm <- statebnds[inconterm,]

# Project map
conterm_p4s <- 
    "+proj=aea +lat_1=29.5 +lat_2=45.5 +lon_0=97.2w"
conterm_albers <- st_transform(conterm, conterm_p4s)

# Store locations
stores <- read.csv("data/walmart-openings-geocoded.csv", 
                   sep=",")
walmarts <- stores[stores$store == "walmart",]
wal_sf <- st_as_sf(walmarts, 
                   coords = c("lng", "lat"), 
                   crs = "+proj=longlat")
wal_sf_albers <- st_transform(wal_sf, conterm_p4s)


#
# Sequence of Maps
#


# Year range
range(walmarts$year)
years <- 1962:2010

# Draw map for each year
par(mfrow = c(7, 7), mar = c(2,0,1,0), oma = c(2,2,2,2))
# par(mfrow = c(10,5), mar = c(1,0,1,0), oma = c(0,0,0,0))
for (yr in years) {
    curr <- wal_sf_albers[wal_sf_albers$year <= yr,]
    plot(st_geometry(conterm_albers), 
         border = "#cccccc", lwd = .2,
         main = yr)
    points(st_coordinates(curr), 
           col="#30437b", pch=16, cex = .2)
}




#
# Animated map
#

saveGIF({
    years <- 1962:2010
    
    par(mar = c(2,0,5,0))
    for (yr in years) {
        
        # Wal-Mart locations open on or before this year
        curr <- wal_sf_albers[wal_sf_albers$year <= yr,]
        
        # Blank map
        plot(st_geometry(conterm_albers), 
             border = "#cccccc", 
             lwd = .2,
             main = yr)
        
        # Previous years
        prev <- curr[curr$year != yr,]
        points(st_coordinates(prev), 
               col="#dbe1f1", pch=20, cex = .3)
        
        # This year
        thisyear <- curr[curr$year == yr,]
        points(st_coordinates(thisyear), 
               col="#30437b")
    }
}, ani.width = 800, ani.height = 500, 
interval = 0.1,
movie.name = "walmart-growth.gif")