#!/usr/bin/env bash
# Create handoff + ADR templates for a PR.
# Usage: bash .opencode/scripts/scaffold-handoff.sh <PR#> <slug>
# Idempotent: does not overwrite existing files.
set -euo pipefail

PR="${1:?Usage: scaffold-handoff.sh <PR#> <slug>}"
SLUG="${2:?Usage: scaffold-handoff.sh <PR#> <slug>}"

REPO_ROOT="$(git rev-parse --show-toplevel 2>/dev/null || echo "")"
if [ -z "$REPO_ROOT" ]; then
    SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
    REPO_ROOT="$(cd "$SCRIPT_DIR/../.." && pwd)"
fi

HANDOFF_DIR="$REPO_ROOT/docs/handoff"
ADR_DIR="$REPO_ROOT/docs/decisions"
mkdir -p "$HANDOFF_DIR" "$ADR_DIR"

HANDOFF="$HANDOFF_DIR/pr-${PR}-${SLUG}.md"
TODAY="$(date +%Y-%m-%d)"

if [ -f "$HANDOFF" ]; then
    echo "handoff already exists: $HANDOFF"
else
    cat > "$HANDOFF" <<EOF
---
pr: ${PR}
title: <заполни>
---

## Что сделано
<заполни>

## Почему
<заполни>

## Pending
<заполни, или «—»>

## Watch out
<заполни, или «—»>
EOF
    echo "created: $HANDOFF"
fi

EXISTING_ADR="$(ls "$ADR_DIR"/*-pr-${PR}-${SLUG}.md 2>/dev/null | head -n1 || true)"
if [ -n "$EXISTING_ADR" ]; then
    ADR="$EXISTING_ADR"
    echo "ADR already exists: $ADR"
else
    # Next ADR number = max(existing) + 1, NOT count + 1.
    # count+1 collides when files are added out of order or in parallel
    # (e.g. two PRs both computed wc -l = 72 → both wrote ADR-073, see issue #176).
    # max+1 is race-resistant: each run reads the current highest number.
    # Guard loop handles the residual race: if max+1 file already exists
    # (created between the max-read and our write), increment to a free slot.
    # 10# forces base-10 (leading zeros like 078 are invalid octal in bash).
    # `|| true` neutralizes grep's exit 1 under set -euo pipefail when the
    # directory is empty (no ADRs yet → max=0 → next=001).
    MAX_N="$(ls "$ADR_DIR" 2>/dev/null | grep -E '^[0-9]{3}-' | cut -c1-3 | sort -n | tail -n1 || true)"
    NEXT_N=$((10#${MAX_N:-0} + 1))
    while :; do
        NN="$(printf "%03d" "$NEXT_N")"
        ADR="$ADR_DIR/${NN}-pr-${PR}-${SLUG}.md"
        if ! ls "$ADR_DIR"/${NN}-pr-*.md >/dev/null 2>&1; then
            break
        fi
        NEXT_N=$((NEXT_N + 1))
    done
    cat > "$ADR" <<EOF
# ADR-${NN}: <title>

## Статус
Accepted (${TODAY})

## Контекст
<заполни, или «—» если архитектурных решений не было>

## Решение
<заполни, или «—»>

## Альтернативы
<заполни, или «—»>
EOF
    echo "created: $ADR"
fi

echo ""
echo "handoff: $HANDOFF"
echo "adr:     $ADR"