#!/bin/sh
# Counterparts Phone: tells Claude Code when new messages arrive at your AI phone number.
# Version 5. From https://counterparts.ai/phone/hook.sh. Runs as a SessionStart and UserPromptSubmit hook in ~/.claude/settings.json.
# Prints one line, only when something arrived since this session's last check (a new session looks back a day, at
# unread messages): how many, and which verified numbers they're from. Never the messages themselves: Claude asks you
# before reading them.
# Reads your key from ~/.config/counterparts-phone/key (the setup text put it there). Keeps its place per Claude Code
# session in ~/.config/counterparts-phone/sessions/ (files unused for 7 days are removed), or in
# ~/.config/counterparts-phone/hook-since when it can't tell which session it's in.
# Gives up after 3 seconds and always exits 0, so it never holds up or stops a prompt.
# It sends its version; when a newer one is out, its line says so (at most once a day; the day is kept in
# ~/.config/counterparts-phone/hook-hint), with the command to save it. It never updates itself.
# To stop it, remove the two entries from ~/.claude/settings.json.

dir="$HOME/.config/counterparts-phone"
[ -r "$dir/key" ] || exit 0

# From the JSON Claude Code passes on stdin, only: session_id (which session this is), hook_event_name and source (so
# the server counts you as there only on a prompt or a session you started or resumed, not on /clear or compaction).
# Nothing else from it is used or sent; on a prompt it holds the prompt too. Without session_id, $CLAUDE_CODE_SESSION_ID.
# It names a file, so letters, digits, _ and - only.
input=
[ -t 0 ] || input=$(cat 2>/dev/null | tr -d '\n')
sid=$(printf '%s' "$input" | sed -n 's/.*"session_id"[[:space:]]*:[[:space:]]*"\([A-Za-z0-9_-]*\)".*/\1/p')
event=$(printf '%s' "$input" | sed -n 's/.*"hook_event_name"[[:space:]]*:[[:space:]]*"\([A-Za-z]*\)".*/\1/p' | cut -c1-40)
source=$(printf '%s' "$input" | sed -n 's/.*"source"[[:space:]]*:[[:space:]]*"\([a-z]*\)".*/\1/p' | cut -c1-20)
# A background task finishing (the watcher's wake) arrives as a "prompt" that is Claude Code's own notification, not
# your words: said as event=notification, so it doesn't count as you being there. Only that word is sent, never the prompt.
if [ "$event" = UserPromptSubmit ] && printf '%s' "$input" | grep -Eq '"prompt"[[:space:]]*:[[:space:]]*"(<|\\u003[cC])task-notification'; then
  event=notification
fi
input=
[ -n "$sid" ] || sid=$CLAUDE_CODE_SESSION_ID
sid=$(printf '%s' "$sid" | tr -cd 'A-Za-z0-9_-' | cut -c1-64)
if [ -n "$sid" ]; then
  mkdir -p "$dir/sessions" 2>/dev/null
  find "$dir/sessions" -type f -mtime +7 -exec rm -f {} + 2>/dev/null
  place="$dir/sessions/$sid.hook"
  url="https://counterparts.ai/phone/api/hook/?unread=1"
else
  place="$dir/hook-since"
  url="https://counterparts.ai/phone/api/hook/"
fi
since=$(cat "$place" 2>/dev/null)
[ -n "$since" ] || since=$(date -u -v-1d +%Y-%m-%dT%H:%M:%SZ 2>/dev/null || date -u -d '1 day ago' +%Y-%m-%dT%H:%M:%SZ 2>/dev/null)

# The key goes in on stdin, so it isn't in the process list.
body=$(printf 'Authorization: Bearer %s\n' "$(cat "$dir/key")" | curl -sfG --connect-timeout 2 --max-time 3 -H @- \
  --data-urlencode "since=$since" --data-urlencode "script=hook/5" \
  --data-urlencode "event=$event" --data-urlencode "source=$source" "$url" 2>/dev/null) || exit 0

# Three lines: a marker, "next_since <time>", and the summary (empty when nothing is new); a fourth, "newer hook/<n>",
# when a newer hook is out.
[ "$(printf '%s\n' "$body" | sed -n 1p)" = "counterparts-hook 1" ] || exit 0
next=$(printf '%s\n' "$body" | sed -n 2p | sed -n 's/^next_since \([0-9][0-9TZ:.+-]*\)$/\1/p')
if [ -n "$next" ]; then
  printf '%s\n' "$next" > "$place.new" 2>/dev/null && mv "$place.new" "$place" 2>/dev/null
fi
# One line, plain letters, digits and punctuation only.
line=$(printf '%s\n' "$body" | sed -n 3p | tr -cd "A-Za-z0-9 _.,;:()'-" | cut -c1-600)
[ -n "$line" ] || exit 0
# A newer hook is out: say so, with the command to save it, once a day on this machine (one save fixes every
# session). The words are this script's own.
if printf '%s\n' "$body" | sed -n 4p | grep -q '^newer hook/[0-9][0-9]*$'; then
  today=$(date -u +%Y-%m-%d)
  if [ "$(cat "$dir/hook-hint" 2>/dev/null)" != "$today" ]; then
    printf '%s\n' "$today" > "$dir/hook-hint" 2>/dev/null
    line="$line"' (A newer version of my message checker is out: ask me, then save it again with: mkdir -p ~/.config/counterparts-phone && curl -sfL https://counterparts.ai/phone/hook.sh -o ~/.config/counterparts-phone/hook.sh && echo "hook saved")'
  fi
fi
printf '%s\n' "$line"
exit 0