#!/bin/bash
set +o histexpand

# Query GitHub labels with perPage pagination support.
#
# Usage: ./query-labels.sh [OPTIONS]
#
# Options:
#   --owner OWNER      Repository owner (required)
#   --repo REPO        Repository name (required)
#   --per-page N       Results per page: 1-100 (default: 10)
#   --page N           Page number (default: 1)
#   --name-filter STR  Case-insensitive substring filter on the label name
#
# Alternatively, inputs can be provided as environment variables using the
# mcp-scripts INPUT_* convention (INPUT_OWNER, INPUT_REPO, INPUT_PERPAGE,
# INPUT_PAGE, INPUT_NAMEFILTER). INPUT_PER_PAGE is also accepted for backward compatibility.
# CLI arguments take precedence over environment variables.
#
# Calls the GitHub REST API:
#   GET /repos/{owner}/{repo}/labels?per_page={n}&page={n}
#
# Returns JSON:
#   { "labels": [...], "item_count": N, "per_page": N, "page": N }

set -e

# Defaults: pick up INPUT_* env vars (mcp-scripts convention) or fall back to
# hardcoded defaults; CLI flags below will override.
# INPUT_PERPAGE (camelCase perPage) is preferred; INPUT_PER_PAGE accepted for
# backward compatibility with callers using the old snake_case convention.
OWNER="${INPUT_OWNER:-}"
REPO="${INPUT_REPO:-}"
PER_PAGE="${INPUT_PERPAGE:-${INPUT_PER_PAGE:-10}}"
PAGE="${INPUT_PAGE:-1}"
NAME_FILTER="${INPUT_NAMEFILTER:-}"

while [[ $# -gt 0 ]]; do
    case $1 in
        --owner)
            OWNER="$2"
            shift 2
            ;;
        --repo)
            REPO="$2"
            shift 2
            ;;
        --per-page)
            PER_PAGE="$2"
            shift 2
            ;;
        --page)
            PAGE="$2"
            shift 2
            ;;
        --name-filter)
            NAME_FILTER="$2"
            shift 2
            ;;
        *)
            echo "Unknown option: $1" >&2
            exit 1
            ;;
    esac
done

if [[ -z "$OWNER" ]]; then
    echo '{"error": "owner is required"}' >&2
    exit 1
fi

if [[ -z "$REPO" ]]; then
    echo '{"error": "repo is required"}' >&2
    exit 1
fi

if ! [[ "$PER_PAGE" =~ ^[0-9]+$ ]] || [[ "$PER_PAGE" -lt 1 ]] || [[ "$PER_PAGE" -gt 100 ]]; then
    echo '{"error": "per_page must be between 1 and 100"}' >&2
    exit 1
fi

if [[ -n "$NAME_FILTER" ]]; then
    RESPONSE=$(gh api --paginate --slurp "repos/${OWNER}/${REPO}/labels?per_page=100" | jq '[.[][]]')
else
    RESPONSE=$(gh api "repos/${OWNER}/${REPO}/labels?per_page=${PER_PAGE}&page=${PAGE}")
fi

echo "$RESPONSE" | jq \
    --argjson per_page "$PER_PAGE" \
    --argjson page "$PAGE" \
    --arg name_filter "$NAME_FILTER" \
    '(if $name_filter == "" then .
      else [.[] | select(.name | ascii_downcase | contains($name_filter | ascii_downcase))]
           | .[(($page - 1) * $per_page):($page * $per_page)]
      end) as $selected
     | {
        labels: [$selected[] | {id, node_id, url, name, color, default, description}],
        item_count: ($selected | length),
        per_page: $per_page,
        page: $page
    }'