#!/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:-}"
ZERO="0000000000000000000000000000000000000000"

# 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}"

# ── 安全回溯：确保 diff 基准覆盖所有未构建的改动 ──
# 问题：concurrency 取消机制会导致前端改动被跳过。被取消的 push 的改动不会被
# 后续 push 的 diff 覆盖到，因为 GITHUB_EVENT_BEFORE 只指向上一次 push 的 SHA。
# 修复：查询最近一次**实际构建了 web 镜像**的成功 push run，用其 head_sha 作为
# diff 基准。这样被取消/跳过的 run 的改动都会被包含在当前 diff 中。
if [ -n "$before" ] && [ "$before" != "$ZERO" ] && [ -n "${GITHUB_TOKEN:-}" ]; then
  BRANCH="${GITHUB_REF_NAME:-}"
  if [ -n "$BRANCH" ]; then
    SAFE_BASE=$(python3 -c "
import json, subprocess, sys

base = '${base}'
repo = '${repo}'
token = '${GITHUB_TOKEN}'
branch = '${BRANCH}'
cur_sha = '${after}'

def check_run(run_id):
    \"\"\"Check if this run actually built the web image.\"\"\"
    try:
        r = subprocess.run(
            ['curl', '-sf', '--max-time', '10',
             '-H', f'Authorization: token {token}',
             f'{base}/repos/{repo}/actions/runs/{run_id}/jobs'],
            capture_output=True, text=True, timeout=15)
        if r.returncode != 0:
            return False
        jobs = json.loads(r.stdout).get('jobs', [])
        return any(
            'Build Staging Web' in j.get('name', '')
            and j.get('conclusion') == 'success'
            for j in jobs
        )
    except Exception:
        return False

try:
    r = subprocess.run(
        ['curl', '-sf', '--max-time', '15',
         '-H', f'Authorization: token {token}',
         f'{base}/repos/{repo}/actions/runs?status=success&event=push&branch={branch}&per_page=30'],
        capture_output=True, text=True, timeout=20)
    if r.returncode != 0:
        sys.exit(0)
    d = json.loads(r.stdout)
    runs = d.get('workflow_runs', []) if isinstance(d, dict) else d
    for run in runs:
        sha = run.get('head_sha', '')
        if sha and sha != cur_sha:
            if check_run(run['id']):
                print(sha)
                break
except Exception:
    pass
" 2>/dev/null || true)

    if [ -n "$SAFE_BASE" ] && [ "$SAFE_BASE" != "$before" ]; then
      echo "🔒 安全回溯: 使用最近实际构建 web 的 commit ${SAFE_BASE:0:8} 替代 before=${before:0:8}"
      before="$SAFE_BASE"
    elif [ -z "$SAFE_BASE" ]; then
      echo "⚠️ 未找到历史成功构建 web 的 push run，保守走全量构建"
      echo "skip_backend=false" >> "$OUTPUT"
      echo "skip_frontend=false" >> "$OUTPUT"
      exit 0
    fi
  fi
fi

FILES=""
if [ -n "$before" ] && [ "$before" != "$ZERO" ]; then
  # Gitea 1.26.x compare API 的顶层 files 字段不填充（始终为空），
  # 但响应里每个 commit 条目自带的 files 完整可用；聚合区间内所有提交的 files 即可。
  API_URL="${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