#!/bin/bash
# CI 公共步骤：检测 push(develop/main) 事件的改动范围
# 输出 skip_backend / skip_frontend（复用 PR check 的语义）
# - 纯前端改动(仅 apps/web/): skip_backend=true
# - 纯后端改动(不含 apps/web/): skip_frontend=true
# - 全栈 / 无法判断: 两者都 false（走全量，安全兜底）
# 需要环境变量: GITHUB_TOKEN, GITHUB_API_URL, GITHUB_REPOSITORY, GITHUB_SHA
set -eu

OUTPUT="${GITHUB_OUTPUT:-/dev/stdout}"

before="${GITHUB_EVENT_BEFORE:-}"
after="${GITHUB_SHA:-}"
repo="${GITHUB_REPOSITORY:-}"
base="${GITHUB_API_URL:-}"

# Gitea Actions 中 push 事件的前一个 SHA 在 event payload 的 before 字段
if [ -z "$before" ] && [ -n "${GITHUB_EVENT_PATH:-}" ] && [ -f "$GITHUB_EVENT_PATH" ]; then
  before=$(python3 -c "
import json,sys
try:
    d=json.load(open('${GITHUB_EVENT_PATH}'))
    print(d.get('before','') or '')
except Exception:
    print('')
")
fi

echo "改动范围检测: before=${before:-<empty>} after=${after}"

FILES=""
if [ -n "$before" ] && [ "$before" != "0000000000000000000000000000000000000000" ]; then
  # Gitea 1.26.x compare API 的顶层 files 字段不填充（始终为空），
  # 但响应里每个 commit 条目自带的 files 完整可用；聚合区间内所有提交的 files 即可。
  API_URL="${base}/repos/${repo}/compare/${before}...${after}?per_page=300"
  for attempt in 1 2 3; do
    FILES=$(curl -s --max-time 30 -H "Authorization: token ${GITHUB_TOKEN}" "$API_URL" \
      | python3 -c "
import json,sys
try:
    d=json.load(sys.stdin)
    files=set()
    for c in d.get('commits', []) or []:
        for f in (c.get('files') or []):
            n = f.get('filename') or ''
            if n:
                files.add(n)
    print('\n'.join(sorted(files)))
except Exception:
    pass
")
    [ -n "$FILES" ] && break
    echo "compare API 无返回，重试 $attempt/3..."
    sleep 3
  done
fi

if [ -z "$FILES" ]; then
  echo "⚠️ 无法获取改动文件列表（新分支/API异常），保守起见走全量构建"
  echo "skip_backend=false" >> "$OUTPUT"
  echo "skip_frontend=false" >> "$OUTPUT"
  exit 0
fi

TOTAL=$(printf '%s\n' "$FILES" | grep -c . || true)
FRONTEND_COUNT=$(printf '%s\n' "$FILES" | grep -c '^apps/web/' || true)
BACKEND_COUNT=$(python3 -c "print($TOTAL - $FRONTEND_COUNT)")

echo "变更文件: ${TOTAL} 个 (前端: ${FRONTEND_COUNT}, 后端/公共: ${BACKEND_COUNT})"

if [ "$BACKEND_COUNT" = "0" ] && [ "$FRONTEND_COUNT" -gt 0 ]; then
  echo "skip_backend=true" >> "$OUTPUT"
  echo "skip_frontend=false" >> "$OUTPUT"
  echo "✅ 纯前端改动，跳过后端镜像构建"
elif [ "$FRONTEND_COUNT" = "0" ] && [ "$BACKEND_COUNT" -gt 0 ]; then
  echo "skip_backend=false" >> "$OUTPUT"
  echo "skip_frontend=true" >> "$OUTPUT"
  echo "🔧 纯后端改动，跳过 Web 镜像构建"
else
  echo "skip_backend=false" >> "$OUTPUT"
  echo "skip_frontend=false" >> "$OUTPUT"
  echo "🔧 包含全栈/公共变更，三个镜像全部构建"
fi