copilot-powerline 0.8.0

#!/usr/bin/env bash
set -euo pipefail

readonly API_URL="https://api.github.com/copilot_internal/user"
readonly FEATURES_URL="https://github.com/settings/copilot/features"
readonly SESSION_PREFIX="copilot-powerline-github-usage-"

# Prints a token identifying a process by its start time, or nothing if the
# process is gone. Paired with the PID, it survives PID reuse.
run_token() {
    local started
    started="$(ps -o lstart= -p "$1" 2>/dev/null)" || return 0
    printf '%s' "$started" | cksum | cut -d' ' -f1
}

SESSION_NAME="${SESSION_PREFIX}$$-$(run_token $$)"
readonly SESSION_NAME

profile="${COPILOT_USAGE_BROWSER_PROFILE:-${HOME}/.copilot/github-usage-profile}"
cache_file="${COPILOT_USAGE_CACHE_FILE:-${HOME}/.copilot/github-usage.json}"
history_file="${COPILOT_USAGE_HISTORY_FILE:-${HOME}/.copilot/github-usage-history.jsonl}"
html_file=""
browser=false
login=false
write_cache=true
write_history=true

usage() {
    cat <<'EOF'
Usage: fetch-github-copilot-usage [--browser] [--login] [--html-file FILE] [--no-cache] [--no-history]

Fetch the signed-in user's GitHub Copilot usage counter for the current
billing cycle and print JSON. By default it reads GitHub's Copilot user API
with your GitHub token (requires curl and jq).

  --browser           Scrape the Copilot settings page with agent-browser instead.
  --login             Open a persistent browser profile for one-time GitHub login.
  --html-file FILE    Parse a saved page text fixture instead of opening a browser.
  --no-cache          Do not write the result to ~/.copilot/github-usage.json.
  --no-history        Do not append the result to ~/.copilot/github-usage-history.jsonl.

Environment:
  COPILOT_GITHUB_TOKEN, GH_TOKEN, GITHUB_TOKEN
                                 GitHub token, checked in this order before
                                 falling back to `gh auth token`.
  COPILOT_USAGE_BROWSER_PROFILE  Persistent browser profile location.
  COPILOT_USAGE_CACHE_FILE       Output cache location.
  COPILOT_USAGE_HISTORY_FILE     Append-only run history location (JSON Lines).
EOF
}

while (($#)); do
    case "$1" in
        --browser)
            browser=true
            ;;
        --login)
            login=true
            ;;
        --html-file)
            shift
            html_file="${1:-}"
            [[ -n "$html_file" ]] || {
                echo "--html-file requires a path" >&2
                exit 2
            }
            ;;
        --no-cache)
            write_cache=false
            ;;
        --no-history)
            write_history=false
            ;;
        -h|--help)
            usage
            exit 0
            ;;
        *)
            echo "Unknown option: $1" >&2
            usage >&2
            exit 2
            ;;
    esac
    shift
done

# Session names end with the PID and start-time token of the run that opened
# them. A session whose run has exited was leaked and may still hold the
# browser profile lock.
close_stale_browser_sessions() {
    local session pid token
    for session in $(agent-browser session list 2>/dev/null |
        grep -Eo "${SESSION_PREFIX}[0-9]+-[0-9]+" || true); do
        token="${session##*-}"
        pid="${session#"$SESSION_PREFIX"}"
        pid="${pid%-*}"
        [[ "$(run_token "$pid")" == "$token" ]] && continue
        agent-browser --session "$session" close >/dev/null 2>&1 || true
    done
}

if "$login"; then
    command -v agent-browser >/dev/null || {
        echo "agent-browser is required. Install it before running --login." >&2
        exit 1
    }

    close_stale_browser_sessions
    # A successful login session stays open for the user; only a failed open is closed.
    agent-browser --session "$SESSION_NAME" --profile "$profile" --headed open "$FEATURES_URL" || {
        status=$?
        agent-browser --session "$SESSION_NAME" close >/dev/null 2>&1 || true
        exit "$status"
    }
    cat <<'EOF'
Sign in to GitHub in the browser window, including SSO or two-factor authentication if required.
Close the window when finished, then run this command again without --login.
EOF
    exit 0
fi

# Prints the first GitHub token found, in Copilot CLI's documented order.
github_token() {
    local name
    for name in COPILOT_GITHUB_TOKEN GH_TOKEN GITHUB_TOKEN; do
        [[ -z "${!name:-}" ]] || {
            printf '%s' "${!name}"
            return
        }
    done
    command -v gh >/dev/null && gh auth token 2>/dev/null
}

# Reads a /copilot_internal/user response and prints "ok<TAB>credits<TAB>cycle",
# or "error<TAB>message" when a field is missing. With no per-user budget
# (unlimited), credits_used is the cycle total; with one, the used part of the
# budget is entitlement - quota_remaining, as VS Code computes it. Cycles are
# calendar months that reset on the 1st, so the cycle is the month before
# quota_reset_date.
# shellcheck disable=SC2016 # A jq program: its $names are jq variables.
readonly API_USAGE_FILTER='
def months: ["January", "February", "March", "April", "May", "June", "July",
    "August", "September", "October", "November", "December"];
def credits:
    if . == null then error("quota_snapshots.premium_interactions is missing")
    elif .unlimited == true then
        if (.credits_used | type) == "number" then .credits_used
        else error("credits_used is missing") end
    elif .unlimited == false then
        if (.entitlement | type) == "number" and .entitlement > 0
            and (.quota_remaining | type) == "number"
        then [0, .entitlement - .quota_remaining] | max
        else error("a per-user budget needs entitlement and quota_remaining") end
    else error("unlimited is missing") end;
def cycle:
    if type != "string" then error("quota_reset_date is missing") else . end
    | (capture("^(?<y>[0-9]{4})-(?<m>[0-9]{2})-01$")
        // error("quota_reset_date \(.) is not the 1st of a month"))
    | (.y | tonumber) as $reset_year
    | (.m | tonumber) as $reset_month
    | (if $reset_month == 1 then [$reset_year - 1, 12]
        else [$reset_year, $reset_month - 1] end) as [$year, $month]
    | (if $month == 2 then
            (if ($year % 4 == 0 and $year % 100 != 0) or $year % 400 == 0
            then 29 else 28 end)
        elif ($month | IN(4, 6, 9, 11)) then 30
        else 31 end) as $days
    | "\(months[$month - 1]) 1-\($days), \($year)";
try "ok\t\(.quota_snapshots.premium_interactions | credits)\t\(.quota_reset_date | cycle)"
catch "error\t\(.)"
'

read_api_usage() {
    local tool token response parsed
    for tool in curl jq; do
        command -v "$tool" >/dev/null || {
            echo "$tool is required. Install it, or pass --browser to scrape the settings page." >&2
            exit 1
        }
    done

    token="$(github_token)" || token=""
    [[ -n "$token" ]] || {
        echo "No GitHub token found. Run gh auth login, or set GH_TOKEN." >&2
        exit 1
    }

    # The token goes in on stdin, so it never shows up in the process list.
    response="$(printf 'Authorization: Bearer %s\n' "$token" |
        curl --silent --show-error --fail --max-time 15 \
            --header @- --header 'Accept: application/json' "$API_URL")" || {
        echo "GitHub API request failed: $API_URL" >&2
        exit 1
    }

    parsed="$(printf '%s' "$response" | jq -r "$API_USAGE_FILTER" 2>/dev/null)" || {
        echo "The GitHub API response is not valid JSON." >&2
        exit 1
    }
    case "$parsed" in
        ok$'\t'*)
            IFS=$'\t' read -r _ credits cycle <<<"$parsed"
            ;;
        *)
            echo "Unexpected Copilot user API response: ${parsed#error$'\t'}" >&2
            exit 1
            ;;
    esac
}

read_page_usage() {
    local page_text
    if [[ -n "$html_file" ]]; then
        [[ -r "$html_file" ]] || {
            echo "Cannot read page text: $html_file" >&2
            exit 1
        }
        page_text="$(<"$html_file")"
    else
        command -v agent-browser >/dev/null || {
            echo "agent-browser is required. Run this script with --login after installing it." >&2
            exit 1
        }

        close_stale_browser_sessions
        cleanup_browser_session() {
            agent-browser --session "$SESSION_NAME" close >/dev/null 2>&1 || true
        }
        trap cleanup_browser_session EXIT
        agent-browser --session "$SESSION_NAME" --profile "$profile" open "$FEATURES_URL" >/dev/null
        page_text="$(agent-browser --session "$SESSION_NAME" read)"
        agent-browser --session "$SESSION_NAME" close >/dev/null
        trap - EXIT
    fi

    if [[ "$page_text" == *"Sign in to GitHub"* ]]; then
        echo "GitHub login is required. Run: $0 --login" >&2
        exit 1
    fi

    if ! credits="$(printf '%s\n' "$page_text" |
        grep -Em1 -o '[0-9][0-9,]* AI credits used' |
        tr -cd '0-9')"; then
        credits=""
    fi

    if ! cycle="$(printf '%s\n' "$page_text" |
        grep -Em1 -o '[A-Z][a-z]+ [0-9]{1,2}-[0-9]{1,2}, [0-9]{4}')"; then
        cycle=""
    fi

    [[ -n "$credits" && -n "$cycle" ]] || {
        echo "Could not find Copilot usage on the features page. GitHub may have changed the page." >&2
        exit 1
    }
}

if "$browser" || [[ -n "$html_file" ]]; then
    read_page_usage
else
    read_api_usage
fi

usd="$(awk -v credits="$credits" 'BEGIN { printf "%.2f", credits / 100 }')"
result="$(printf '{"ai_credits_used":%s,"usd":"%s","cycle":"%s"}' "$credits" "$usd" "$cycle")"

if "$write_cache"; then
    umask 077
    mkdir -p "$(dirname "$cache_file")"
    temporary_cache="$(mktemp "${cache_file}.tmp.XXXXXX")"
    printf '%s\n' "$result" >"$temporary_cache"
    mv "$temporary_cache" "$cache_file"
fi

if "$write_history"; then
    umask 077
    mkdir -p "$(dirname "$history_file")"
    timestamp="$(date -u +%Y-%m-%dT%H:%M:%SZ)"
    printf '{"ts":"%s","ai_credits_used":%s,"usd":"%s","cycle":"%s"}\n' \
        "$timestamp" "$credits" "$usd" "$cycle" >>"$history_file"
fi

printf '%s\n' "$result"