#!/usr/bin/env bash
#
# dropkind — send articles and documents to your Kindle from the terminal.
#
# Install:
#   curl -fsSL https://dropkind.app/install.sh | sh
#
# Usage:
#   dropkind login                 store your API token (get one at https://dropkind.app/settings/api)
#   dropkind send <url-or-file>    deliver a web article or a document
#   dropkind send - [--title T]    deliver plain text read from stdin
#   dropkind status <id>           check a drop
#   dropkind logout                forget the stored token
#
# Environment:
#   DROPKIND_TOKEN                 use this token instead of the stored one
#   DROPKIND_URL                   API base URL (default: https://dropkind.app)

set -euo pipefail

VERSION="0.1.1"
BASE_URL="${DROPKIND_URL:-https://dropkind.app}"
CONFIG_DIR="${XDG_CONFIG_HOME:-$HOME/.config}/dropkind"
TOKEN_FILE="$CONFIG_DIR/token"

die() {
  echo "dropkind: $*" >&2
  exit 1
}

usage() {
  sed -n 's/^# \{0,1\}//p' "$0" | sed -n '2,17p'
}

token() {
  if [ -n "${DROPKIND_TOKEN:-}" ]; then
    echo "$DROPKIND_TOKEN"
  elif [ -f "$TOKEN_FILE" ]; then
    cat "$TOKEN_FILE"
  else
    die "no API token. Run 'dropkind login' first (get a token at $BASE_URL/settings/api)"
  fi
}

# json_get <key> — extract a top-level field from JSON on stdin.
json_get() {
  if command -v python3 >/dev/null 2>&1; then
    python3 -c 'import json,sys
try:
    value = json.load(sys.stdin).get(sys.argv[1])
except Exception:
    value = None
print("" if value is None else value)' "$1"
  else
    sed -n "s/.*\"$1\":[[:space:]]*\"\([^\"]*\)\".*/\1/p; s/.*\"$1\":[[:space:]]*\([0-9][0-9]*\).*/\1/p" | head -1
  fi
}

# api_request <method> <path> [curl args...] — sets STATUS and BODY.
api_request() {
  local method="$1" path="$2" tmp
  shift 2
  tmp="$(mktemp)"
  STATUS="$(curl -sS -o "$tmp" -w '%{http_code}' -X "$method" \
    -H "Authorization: Bearer $(token)" \
    "$@" "$BASE_URL$path")" || { rm -f "$tmp"; die "could not reach $BASE_URL"; }
  BODY="$(cat "$tmp")"
  rm -f "$tmp"
}

fail_from_response() {
  local fallback="$1" message
  message="$(printf '%s' "$BODY" | json_get error)"
  case "$STATUS" in
    401) die "invalid or expired token. Run 'dropkind login' with a fresh token from $BASE_URL/settings/api" ;;
    403) die "${message:-account setup incomplete. Finish onboarding at $BASE_URL first}" ;;
    429) die "rate limited — try again in a minute" ;;
    *) die "${message:-$fallback (HTTP $STATUS)}" ;;
  esac
}

cmd_login() {
  local input
  printf 'Paste your API token (from %s/settings/api): ' "$BASE_URL"
  read -rs input
  echo
  [ -n "$input" ] || die "no token entered"

  # Probing drop 0: a valid token earns a JSON not_found, a bad one a 401,
  # and a server without the API an HTML 404.
  local tmp
  tmp="$(mktemp)"
  STATUS="$(curl -sS -o "$tmp" -w '%{http_code}' \
    -H "Authorization: Bearer $input" \
    "$BASE_URL/api/v1/drops/0")" || { rm -f "$tmp"; die "could not reach $BASE_URL"; }
  BODY="$(cat "$tmp")"
  rm -f "$tmp"
  case "$STATUS" in
    401) die "that token was not accepted" ;;
    404) printf '%s' "$BODY" | grep -q not_found || die "no DropKind API at $BASE_URL (HTTP 404)" ;;
  esac

  mkdir -p "$CONFIG_DIR"
  printf '%s' "$input" > "$TOKEN_FILE"
  chmod 600 "$TOKEN_FILE"
  echo "Token saved to $TOKEN_FILE"
}

cmd_logout() {
  rm -f "$TOKEN_FILE"
  echo "Token removed"
}

cmd_send() {
  local target="" title="" id status
  while [ $# -gt 0 ]; do
    case "$1" in
      -t|--title) title="${2:-}"; shift 2 ;;
      -?*) die "unknown option: $1" ;;
      *) [ -z "$target" ] || die "only one URL or file per send"; target="$1"; shift ;;
    esac
  done
  [ -n "$target" ] || die "usage: dropkind send <url-or-file|-> [--title TITLE]"

  local -a form
  if [ "$target" = "-" ]; then
    local text
    text="$(cat)"
    [ -n "$text" ] || die "nothing on stdin to send"
    form=(--form-string "text=$text")
  elif [ -f "$target" ]; then
    form=(-F "file=@$target")
  elif printf '%s' "$target" | grep -qiE '^https?://'; then
    form=(--form-string "url=$target")
  else
    die "'$target' is neither an existing file, an http(s) URL, nor '-' for stdin"
  fi
  [ -z "$title" ] || form+=(--form-string "title=$title")

  api_request POST /api/v1/drops "${form[@]}"
  [ "$STATUS" = "201" ] || fail_from_response "drop was not accepted"

  id="$(printf '%s' "$BODY" | json_get id)"
  echo "Drop #$id queued. Check it with: dropkind status $id"
}

cmd_status() {
  local id="${1:-}" status title sent_at web_url detail
  [ -n "$id" ] || die "usage: dropkind status <id>"

  api_request GET "/api/v1/drops/$id"
  [ "$STATUS" = "200" ] || fail_from_response "drop not found"

  status="$(printf '%s' "$BODY" | json_get status)"
  title="$(printf '%s' "$BODY" | json_get title)"
  sent_at="$(printf '%s' "$BODY" | json_get sent_at)"
  echo "Drop #$id: $status${title:+ — $title}${sent_at:+ (sent $sent_at)}"
  case "$status" in
    needs_action|failed)
      detail="$(printf '%s' "$BODY" | json_get detail)"
      web_url="$(printf '%s' "$BODY" | json_get web_url)"
      if [ -n "$detail" ]; then
        echo "  $detail"
      elif [ -n "$web_url" ]; then
        echo "  see $web_url"
      fi
      ;;
  esac
}

case "${1:-}" in
  login) shift; cmd_login "$@" ;;
  logout) shift; cmd_logout "$@" ;;
  send) shift; cmd_send "$@" ;;
  status) shift; cmd_status "$@" ;;
  -v|--version|version) echo "dropkind $VERSION" ;;
  ""|-h|--help|help) usage ;;
  *) die "unknown command: $1 (try 'dropkind help')" ;;
esac