#!/bin/bash
# TODO:
#   - save last 5 VODlists and offer replay function to avoid refetching unnecesarily


# ${1} (optional) username to search VODs of

[ "${1}" = "-h" ] || [ "${1}" = "--help" ] && {
  printf "usage: getvods <username(optional)>\n"
  exit 0
}

# ${1} is a string with error reason stated
# ${2} is an optional string to report a different error status
on_fail(){
  printf "last ran command error status: %s\n" "${2:-${?}}"
  printf "error: %s\n" "${1}"
  exit 2
}

CFG_DIR="${HOME}/.config/getvods"
[ ! -d "${CFG_DIR}" ] && {
  mkdir -p "${CFG_DIR}" || on_fail "${CFG_DIR} doesn't exist and couldn't be made (check write permissions to ${CFG_DIR})"
}

# get twitch api credentials
[ ! -f "${CFG_DIR}/client_id" ] && {
  read -p "enter your twitch API client_id >" client_id
  [ ! -z "${client_id}" ] && printf "%s" "${client_id}" > "${CFG_DIR}/client_id" || on_fail "couldn't write client_id to ${CFG_DIR}/client_id"
} || client_id="$(cat "${CFG_DIR}/client_id")"
[ ! -f "${CFG_DIR}/client_secret" ] && {
  read -p "enter your twitch API client_secret >" client_secret
  [ ! -z "${client_secret}" ] && printf "%s" "${client_secret}" > "${CFG_DIR}/client_secret" || on_fail "couldn't write client_secret to ${CFG_DIR}/client_secret"
} || client_secret="$(cat "${CFG_DIR}/client_secret")"

# get access token
get_token(){
  curl -s -X POST https://id.twitch.tv/oauth2/token -d "client_id=${client_id}" -d "client_secret=${client_secret}" -d "grant_type=client_credentials" > "${CFG_DIR}/token.json" || {
    last_err="${?}"
    rm "${CFG_DIR}/token.json" 2>/dev/null
    on_fail "couldn't get token (curl error)" "${last_err}"
  }
  bc -l <<< "$(date +%s) + $(grep -o "expires_in\":[0-9]\+" "${CFG_DIR}/token.json" | awk -F : '{print $2}')" > "${CFG_DIR}/expiration.txt" || {
    last_err="${?}"
    rm "${CFG_DIR}/expiration.txt" 2>/dev/null
    on_fail "couldn't save expiration date" "${last_err}"
  }
}

[ -f "${CFG_DIR}/token.json" ] && [ -f "${CFG_DIR}/expiration.txt" ] && {
  [ "$(cat "${CFG_DIR}/expiration.txt")" -le "$(date +%s)" ] && get_token || :
} || {
  get_token
}

access_token="$(grep -o "access_token\":\"[a-zA-Z0-9]\+" "${CFG_DIR}/token.json" | awk -F \" '{print $3}')"
[ -z "${access_token}" ] && {
  last_err="${?}"
  rm "${CFG_DIR}/token.json"
  on_fail "couldn't get token (token empty)" "${last_err}"
}

# get the username to search for
declare -i retries=0
[ ! -z "${1}" ] && {
  while :; do
    [ "${#1}" -ge "4" ] && [ "${#1}" -le "25" ] && grep "[a-zA-Z0-9_]\{4,25\}" <<< "${1}" >/dev/null && {
      login="${1}"
      break
    }
    printf "username must be between 4 and 25 characters long\n"
    printf "username may have only characters a-z A-Z 0-9 and _\n"
    retries+=1
  done
}
[ -z "${login}" ] && {
  while :; do
    read -p 'type in username >' login
    [ "${#login}" -ge "4" ] && [ "${#login}" -le "25" ] && grep "[a-zA-Z0-9_]\{4,25\}" <<< "${login}" >/dev/null && break
    printf "username must be between 4 and 25 characters long\n"
    printf "username may have only characters a-z A-Z 0-9 and _\n"
    retries+=1
    [ "${retries}" -ge 3 ] && on_fail "exceeded max retries" "1"
  done
}

# get user id
[ ! -f "${CFG_DIR}/userlist.txt" ] || [ "${login}" != "$(grep "${login}" "${CFG_DIR}/userlist.txt" | awk -F ":|," '{print $4}')" ] && {
  user_response="$(curl -s -G -X GET "https://api.twitch.tv/helix/users" -d "login=${login}" -H "Authorization: Bearer ${access_token}" -H "client-id: ${client_id}")"
  last_err="${?}"
  [ "${last_err}" -gt 0 ] && on_fail "couldn't get user_id (curl error)" "${last_err}"
  parsed_user_response="$(grep -o "id\":\"[0-9]\+\",\"login\":\"[a-zA-Z0-9_]\{4,25\}" <<< "${user_response}")"
  last_err="${?}"
  [ "${last_err}" -gt 0 ] && on_fail "couldn't get user_id (user_id empty)" "${last_err}"
  unset user_response
  sed 's/\"//g' <<< "${parsed_user_response}" >> "${CFG_DIR}/userlist.txt"
  unset parsed_user_response
}
user_id="$(grep "${login}" "${CFG_DIR}/userlist.txt" | awk -F ":|," '{print $2}')"

# save json with first 20 videos tied to the user id we just got
vodlist="$(curl -s -G -X GET "https://api.twitch.tv/helix/videos" -d "type=archive" -d "user_id=${user_id}" -H "Authorization: Bearer ${access_token}" -H "client-id: ${client_id}")"
last_err="${?}"
unset client_secret client_id
[ "${last_err}" -gt 0 ] && on_fail "couldn't get VOD list (curl error)" "${last_err}"
parsed_vodlist="$(sed 's/^{"data":\[\|],"pagination":{\("cursor":"[a-zA-Z0-9]\+"\)\?}}$//g' <<< "${vodlist}")"
unset vodlist
[ -z "${parsed_vodlist}" ] && on_fail "vodlist empty (no VODs found for ${login})"
printf "%s" "${parsed_vodlist}" > "${CFG_DIR}/streamarchives.json"
unset parsed_vodlist

unset user_id last_err vodlist parsed_vodlist

utf-16-surrogate-pair-decode() {
  # shamelessly stolen from stackoverflow
  local out="$1"
  local remain=""
  local regexp='(.*)\\u[dD]([0-9a-fA-F]{3})\\u[dD]([0-9a-fA-F]{3})(.*)'
  while [[ "${out}" =~ "${regexp}" ]] ; do
   # match 2 \udxxx hex values, calculate new U, then split and replace
   local W1="$(( ( 0xd${BASH_REMATCH[2]} & 0x3ff) <<10 ))"
   local W2="$(( 0xd${BASH_REMATCH[3]} & 0x3ff ))"
   U="$(( ( W1 | W2 ) + 0x10000 ))"
   remain="$(printf '\\U%8.8x' "${U}")${BASH_REMATCH[4]}${remain}"
   out="${BASH_REMATCH[1]}"
  done
  printf "${out}${remain}\n" 2>/dev/null
}

printf "VODs of ${login}\n"

declare -a titles
declare -a duration
declare -a urls

declare -i j=0
while IFS= read -r i; do
  titles[${j}]="$(utf-16-surrogate-pair-decode "${i:9:-2}")"
  j+=1
done < <(grep -o '"title":"\(\\"\|[^"]*\)*",' "${CFG_DIR}/streamarchives.json")

j=0
while IFS= read -r i; do
  duration[${j}]="${i:12:-1}"
  j+=1
done < <(grep -o "\"duration\":\"[a-z0-9]\+\"" "${CFG_DIR}/streamarchives.json")

j=0
while IFS= read -r i; do
  urls[${j}]="${i:7:-1}"
  j+=1
done < <(grep -o "\"url\":\"https://www\.twitch\.tv/videos/[0-9]\+\"" "${CFG_DIR}/streamarchives.json")
unset j

for i in {0..19}; do
  printf "%s:\t%s %s\n" "$((${i}+1))" "${titles[${i}]}" "${duration[${i}]}"
done

retries=0
while :; do
  read -p "choose a video from the list (type 1-20) >" choice
  grep "[0-9]\{1,2\}" <<< "${choice}" >/dev/null && [ "${choice}" -ge 0 ] && [ "${choice}" -le 20 ] && break
  printf "%s is not a number from 1-20\n" "${choice}"
  retries+=1
  [ "${retries}" -ge 3 ] && on_fail "exceeded max retries" "1"
done
printf "%s" "${urls[$((${choice}-1))]}" | xclip -selection clipboard