#include "stdafx.h"
#include "SectionPerfCounter.h"

#include <windows.h>
#include <stdlib.h>
#include <string>
#include <map>
#include <set>

namespace
{
	// 单个计数器：次数 + 累计耗时（µs）
	struct Entry
	{
		Entry() : nCount(0), nTotalUs(0), nMaxUs(0) {}

		unsigned long long nCount;
		unsigned long long nTotalUs;
		unsigned long long nMaxUs;
	};

	// 唯一 hash 表的上限：正常图纸几十到几百个唯一截面，
	// 万一文本各不相同（说明缓存没意义）也不让内存无限涨
	const size_t kMaxUniqueHash = 50000;

	struct Stats
	{
		Stats()
			: bInited(false), bEnabled(false)
			, nRegionTexts(0), nUniqueHashes(0), nSimulatedHits(0), bHashTableOverflow(false)
			, nTempFiles(0), nTempFileBytes(0)
			, nWriteBacks(0)
		{
		}

		bool bInited;
		bool bEnabled;

		std::map<std::string, Entry> entries;   // tag -> 次数/耗时

		unsigned long long nRegionTexts;        // 一共恢复过多少份 SAT 文本
		size_t             nUniqueHashes;       // 其中不同内容有多少
		unsigned long long nSimulatedHits;      // 若做内容缓存，能命中多少次
		bool               bHashTableOverflow;

		std::set<unsigned long long> hashSeen;

		unsigned long long nTempFiles;          // 临时文件写入次数
		unsigned long long nTempFileBytes;      // 临时文件累计字节

		unsigned long long nWriteBacks;         // Region -> SAT 文本 次数
	};

	// 故意用函数内 static：AGENTS.md 禁止文件级 static。
	// CoreLibrary 是静态库且只被 CoreCommand 链接，
	// 所以这里的实例在 CoreCommand.arx 里是唯一的一份。
	Stats& GetStats()
	{
		static Stats s_stats;
		if (!s_stats.bInited)
		{
			s_stats.bInited = true;
#ifndef NDEBUG
			const char* psz = ::getenv("AEC_PERF_COUNTER");
			s_stats.bEnabled = (psz != NULL && psz[0] != '\0' && psz[0] != '0');
#else
			s_stats.bEnabled = false;
#endif
		}
		return s_stats;
	}

	long long NowTicks()
	{
		LARGE_INTEGER li;
		::QueryPerformanceCounter(&li);
		return (long long)li.QuadPart;
	}

	unsigned long long TicksToUs(long long nTicks)
	{
		static long long nFreq = 0;
		if (nFreq == 0)
		{
			LARGE_INTEGER li;
			if (!::QueryPerformanceFrequency(&li) || li.QuadPart == 0)
				nFreq = 1;
			else
				nFreq = (long long)li.QuadPart;
		}
		if (nTicks <= 0)
			return 0;
		return (unsigned long long)((nTicks * 1000000LL) / nFreq);
	}

	// FNV-1a 64
	unsigned long long Hash64(const char* pszTxt, size_t nLen)
	{
		unsigned long long h = 1469598103934665603ULL;
		for (size_t i = 0; i < nLen; ++i)
		{
			h ^= (unsigned char)pszTxt[i];
			h *= 1099511628211ULL;
		}
		return h;
	}

	Entry& GetEntry(const char* pszTag)
	{
		Stats& s = GetStats();
		std::string key(pszTag ? pszTag : "?");
		return s.entries[key];
	}

	std::string TempReportPath()
	{
		char szTmp[MAX_PATH + 1];
		::memset(szTmp, 0, sizeof(szTmp));
		DWORD n = ::GetTempPathA(MAX_PATH, szTmp);
		if (n == 0 || n >= MAX_PATH)
			return std::string("aec_section_perf.txt");
		std::string s(szTmp);
		s += "aec_section_perf.txt";
		return s;
	}
}

namespace SectionPerf
{
	bool Enabled()
	{
		return GetStats().bEnabled;
	}

	Scope::Scope(const char* pszTag)
		: m_pszTag(pszTag), m_nStart(0), m_bActive(false)
	{
		if (!GetStats().bEnabled)
			return;
		m_bActive = true;
		m_nStart = NowTicks();
	}

	Scope::~Scope()
	{
		if (!m_bActive)
			return;

		const unsigned long long nUs = TicksToUs(NowTicks() - m_nStart);
		Entry& e = GetEntry(m_pszTag);
		++e.nCount;
		e.nTotalUs += nUs;
		if (nUs > e.nMaxUs)
			e.nMaxUs = nUs;
	}

	void NoteRegionText(const char* pszTxt, size_t nLen)
	{
		Stats& s = GetStats();
		if (!s.bEnabled)
			return;
		if (pszTxt == NULL || nLen == 0)
			return;

		++s.nRegionTexts;

		const unsigned long long h = Hash64(pszTxt, nLen);
		if (s.hashSeen.find(h) != s.hashSeen.end())
		{
			++s.nSimulatedHits;
			return;
		}
		if (s.hashSeen.size() < kMaxUniqueHash)
		{
			s.hashSeen.insert(h);
			++s.nUniqueHashes;
		}
		else
		{
			s.bHashTableOverflow = true;
		}
	}

	void NoteTempFile(size_t nBytes)
	{
		Stats& s = GetStats();
		if (!s.bEnabled)
			return;
		++s.nTempFiles;
		s.nTempFileBytes += (unsigned long long)nBytes;
	}

	void NoteWriteBack(const char* pszTag)
	{
		Stats& s = GetStats();
		if (!s.bEnabled)
			return;
		++s.nWriteBacks;
		(void)pszTag;
	}

	void Dump()
	{
		Stats& s = GetStats();
		if (!s.bEnabled)
		{
			acutPrintf(_T("\n[SectionPerf] not enabled: set AEC_PERF_COUNTER=1 before starting CAD (Debug build only)."));
			return;
		}

		// 报告正文全 ASCII：控制台用 %hs 直出，落文件也直接可读
		std::string out;
		char szLine[1024];

		out += "\n================ SectionPerf (Phase 0) ================\n";

		sprintf_s(szLine, sizeof(szLine), "RegionTexts=%llu  UniqueHashes=%llu  SimulatedHits=%llu  HitRate=%.1f%%\n",
			s.nRegionTexts, (unsigned long long)s.nUniqueHashes, s.nSimulatedHits,
			s.nRegionTexts ? (100.0 * (double)s.nSimulatedHits / (double)s.nRegionTexts) : 0.0);
		out += szLine;
		if (s.bHashTableOverflow)
			out += "  (hash table capped: UniqueHashes is under-counted, HitRate over-estimated)\n";

		sprintf_s(szLine, sizeof(szLine), "TempFiles=%llu  TempBytes=%llu  WriteBacks=%llu\n",
			s.nTempFiles, s.nTempFileBytes, s.nWriteBacks);
		out += szLine;

		out += "---- timing (by tag) ----\n";
		out += "  count      total_ms    avg_us      max_us   tag\n";
		for (std::map<std::string, Entry>::const_iterator it = s.entries.begin();
			it != s.entries.end(); ++it)
		{
			const Entry& e = it->second;
			const double avgUs = e.nCount ? ((double)e.nTotalUs / (double)e.nCount) : 0.0;
			sprintf_s(szLine, sizeof(szLine), "  %-9llu %10.1f %10.1f %10llu   %s\n",
				e.nCount, (double)e.nTotalUs / 1000.0, avgUs, e.nMaxUs, it->first.c_str());
			out += szLine;
		}
		out += "=======================================================\n";

		// 逐行输出：%hs 把窄字符串塞进 TCHAR 格式串，不涉及宽字符转换
		const char* psz = out.c_str();
		while (*psz != '\0')
		{
			const char* pszEnd = strchr(psz, '\n');
			const size_t nSeg = (pszEnd != NULL) ? (size_t)(pszEnd - psz) : strlen(psz);
			if (nSeg > 0 && nSeg < sizeof(szLine))
			{
				memcpy(szLine, psz, nSeg);
				szLine[nSeg] = '\0';
				acutPrintf(_T("\n%hs"), szLine);
			}
			if (pszEnd == NULL)
				break;
			psz = pszEnd + 1;
		}

		// 同时落文件，方便事后拿去做分析
		const std::string sPath = TempReportPath();
		FILE* fp = NULL;
		if (fopen_s(&fp, sPath.c_str(), "a") == 0 && fp != NULL)
		{
			fprintf(fp, "%s", out.c_str());
			fclose(fp);
		}
	}

	void Reset()
	{
		Stats& s = GetStats();
		s.entries.clear();
		s.hashSeen.clear();
		s.nRegionTexts = 0;
		s.nUniqueHashes = 0;
		s.nSimulatedHits = 0;
		s.bHashTableOverflow = false;
		s.nTempFiles = 0;
		s.nTempFileBytes = 0;
		s.nWriteBacks = 0;
	}
}