---
title: "Topic 8"
output: html_document
date: "`r Sys.Date()`"
---

```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE)
```

# Download data
from OpenSky https://opensky-network.org/datasets/states/#flights/
```{r download}
library(dplyr)
library(lubridate)
library(readr)
library(utils)

# -------------------------------
# Step 1: Define dates
# -------------------------------
dates <- seq(as.Date("2022-09-01"), as.Date("2022-09-05"), by = "days")

tmp_dir <- tempdir()
all_flights <- list()

# -------------------------------
# Step 2: Download each day's CSV
# -------------------------------
for(d in dates) {
  d <- as.Date(d)
  
  file_name <- paste0("flight_sample_", d, ".csv.gz")
  url <- paste0("https://s3.opensky-network.org/data-samples/flightsV5/", file_name)
  
  message("Downloading: ", url)
  
  dest <- file.path(tmp_dir, file_name)
  
  tryCatch({
    download.file(url, dest, mode = "wb")
    
    # read csv
    df <- read_csv(dest, col_types = cols(.default = "c"))
    all_flights[[length(all_flights)+1]] <- df
  }, error = function(e) {
    warning("Failed to download ", file_name)
  })
}

# -------------------------------
# Step 3: Combine all days
# -------------------------------
flight_data <- bind_rows(all_flights)

# -------------------------------
# Step 4: Inspect data
# -------------------------------
head(flight_data)
colnames(flight_data)
str(flight_data)

if(interactive()) {
  View(flight_data)
}

# -------------------------------
# Step 5: Filter flight BEL40V
# -------------------------------
flight_number <- "BEL40V"

if("callsign" %in% colnames(flight_data)) {
  flight_BEL40V <- flight_data %>%
    filter(callsign == flight_number)
  
  # save
  write_csv(flight_BEL40V, "flight_BEL40V.csv")
  
  # view first row
  head(flight_BEL40V)
} else {
  warning("Column 'callsign' not found in flight_data!")
}
```