#!/usr/bin/env bash
#
# Fetches a GitHub issue (title + body + labels/state/url) into a local markdown file.
#
# Usage:
# fetch_github_issue.sh <issue-number> [--out <path>]
#
# Output on success (when --out is used):
# OK <path>
#
# Output on failure:
# ERROR <message>
#
# Exit codes:
# 0 - Success
# 1 - Missing/invalid arguments
# 3 - GitHub CLI not authenticated
# 4 - Failed to fetch issue
# 5 - Failed to write output file
set -euo pipefail
if [[ $# -lt 1 || -z "${1:-}" ]]; then
echo "ERROR Missing GitHub issue number argument"
exit 1
fi
ISSUE_NUMBER="$1"
shift
OUT=""
if [[ $# -gt 0 ]]; then
if [[ "${1:-}" == "--out" ]]; then
if [[ $# -lt 2 || -z "${2:-}" ]]; then
echo "ERROR --out requires a non-empty path"
exit 1
fi
OUT="$2"
shift 2
else
echo "ERROR Unknown argument: ${1:-}"
exit 1
fi
fi
if [[ $# -gt 0 ]]; then
echo "ERROR Too many arguments"
exit 1
fi
if [[ ! "$ISSUE_NUMBER" =~ ^[0-9]+$ ]]; then
echo "ERROR Issue number must be digits (example: 326)"
exit 1
fi
if ! gh auth status &>/dev/null; then
echo "ERROR GitHub CLI not authenticated. Run: gh auth login"
exit 3
fi
CMD=(gh issue view "$ISSUE_NUMBER")
set +e
MD="$("${CMD[@]}" --json title,body,url,state,labels --template \
'{{printf "# %s\n\n" .title -}}
{{printf "Source: %s\n" .url -}}
{{printf "State: %s\n" .state -}}
{{- printf "Labels: " -}}
{{- if .labels -}}
{{- range $i, $l := .labels -}}
{{- if $i -}}, {{- end -}}
{{- $l.name -}}
{{- end -}}
{{- else -}}None{{- end -}}
{{printf "\n\n## Body\n\n%s\n" .body -}}' 2>&1)"
STATUS=$?
set -e
if [[ $STATUS -ne 0 ]]; then
FIRST_LINE="$(printf "%s" "$MD" | head -n 1)"
echo "ERROR Failed to fetch issue via gh: ${FIRST_LINE}"
exit 4
fi
if [[ -n "$OUT" ]]; then
OUT_DIR="$(dirname -- "$OUT")"
if [[ ! -d "$OUT_DIR" ]]; then
echo "ERROR Output directory does not exist: ${OUT_DIR}"
exit 5
fi
if [[ ! -w "$OUT_DIR" ]]; then
echo "ERROR Output directory is not writable: ${OUT_DIR}"
exit 5
fi
if ! printf "%s" "$MD" >"$OUT"; then
echo "ERROR Failed to write output file: ${OUT}"
exit 5
fi
echo "OK $OUT"
else
printf "%s" "$MD"
fi
