#include "record_manager.hpp"

#include <algorithm>
#include <ctime>
#include <iostream>

namespace fs = std::filesystem;

RecordManager::RecordManager(const std::string& base_dir) : base_dir_(base_dir) {}

//
// 扫描所有文件
//
void RecordManager::scanAll()
{
    index_.clear();

    if (!fs::exists(base_dir_)) return;

    for (auto const& entry : fs::recursive_directory_iterator(base_dir_))
    {
        if (!entry.is_regular_file()) continue;

        auto p = entry.path();
        if (p.extension() != ".mp4") continue;

        auto info = parseFile(p);
        if (info.start_ms <= 0) continue;

        index_[info.stream].push_back(info);
    }

    // 各 stream 排序
    for (auto& kv : index_)
    {
        sortStream(kv.first);
    }
}

//
// 排序函数：按 start_ms 升序
//
void RecordManager::sortStream(const std::string& stream)
{
    auto& files = index_[stream];

    std::sort(files.begin(), files.end(),
              [](const RecordFileInfo& a, const RecordFileInfo& b) { return a.start_ms < b.start_ms; });
}

//
// 解析路径得到文件时间戳
//
// 格式：
/// sata/record/AHD1_main/2025-11-13/10/10-23-17.mp4
//
RecordFileInfo RecordManager::parseFile(const fs::path& p)
{
    RecordFileInfo info;
    info.path = p.string();

    try
    {
        // 目录结构倒推
        auto filename = p.filename().string();                              // 10-23-17.mp4
        auto hour_dir = p.parent_path().filename().string();                // 10
        auto date_dir = p.parent_path().parent_path().filename().string();  // 2025-11-13
        auto stream_dir = p.parent_path().parent_path().parent_path().filename().string();

        info.stream = stream_dir;

        // 日期解析
        int y = 0, mon = 0, d = 0;
        sscanf(date_dir.c_str(), "%d-%d-%d", &y, &mon, &d);

        // 文件名解析 H-M-S
        int h = 0, m = 0, s = 0;
        sscanf(filename.c_str(), "%d-%d-%d", &h, &m, &s);

        std::tm t{};
        t.tm_year = y - 1900;
        t.tm_mon = mon - 1;
        t.tm_mday = d;
        t.tm_hour = h;
        t.tm_min = m;
        t.tm_sec = s;

        int64_t epoch = std::mktime(&t) * 1000LL;
        info.start_ms = epoch;
        info.end_ms = epoch + 60 * 1000;  // 默认 1 分钟
    }
    catch (...)
    {
        info.start_ms = -1;
        info.end_ms = -1;
    }

    return info;
}

//
// 查询某段时间的录像段
//
std::vector<RecordSegment> RecordManager::querySegments(const std::string& stream, int64_t start_ms, int64_t end_ms)
{
    std::vector<RecordSegment> result;

    if (!index_.count(stream)) return result;

    const auto& files = index_[stream];

    std::vector<RecordFileInfo> hits;

    // 先找到落在时间区间内的文件
    for (const auto& f : files)
    {
        bool overlap = !(f.end_ms <= start_ms || f.start_ms >= end_ms);

        if (overlap) hits.push_back(f);
    }

    if (hits.empty()) return result;

    // 合并连续文件为段
    std::sort(hits.begin(), hits.end(), [](auto& a, auto& b) { return a.start_ms < b.start_ms; });

    int idx = 1;
    RecordSegment seg{};
    seg.index = idx;
    seg.start_ms = hits[0].start_ms;
    seg.files.push_back(hits[0]);
    seg.end_ms = hits[0].end_ms;
    seg.segment_id = hits[0].stream + "_" + std::to_string(seg.start_ms) + "_" + std::to_string(seg.end_ms);

    for (size_t i = 1; i < hits.size(); ++i)
    {
        auto& prev = hits[i - 1];
        auto& cur = hits[i];

        bool continuous = (cur.start_ms <= prev.end_ms + 1500);  // 允许 1.5 秒误差

        if (continuous)
        {
            seg.files.push_back(cur);
            seg.end_ms = cur.end_ms;
        }
        else
        {
            // 关闭上一段
            seg.segment_id =
                seg.files[0].stream + "_" + std::to_string(seg.start_ms) + "_" + std::to_string(seg.end_ms);
            result.push_back(seg);

            // 开新段
            idx++;
            seg = RecordSegment{};
            seg.index = idx;
            seg.files.push_back(cur);
            seg.start_ms = cur.start_ms;
            seg.end_ms = cur.end_ms;
        }
    }

    // 最后一段补进去
    seg.segment_id = seg.files[0].stream + "_" + std::to_string(seg.start_ms) + "_" + std::to_string(seg.end_ms);
    result.push_back(seg);

    return result;
}

//
// 根据 segmentId 反查 segment
//
RecordSegment RecordManager::getSegment(const std::string& segmentId)
{
    // segmentId 格式：
    // AHD1_main_1731465600000_1731467400000

    auto pos1 = segmentId.find('_');
    auto pos2 = segmentId.find('_', pos1 + 1);
    if (pos1 == std::string::npos || pos2 == std::string::npos) return {};

    std::string stream = segmentId.substr(0, pos1);
    int64_t start_ms = std::stoll(segmentId.substr(pos1 + 1, pos2 - pos1 - 1));
    int64_t end_ms = std::stoll(segmentId.substr(pos2 + 1));

    auto segs = querySegments(stream, start_ms, end_ms);

    for (auto& s : segs)
    {
        if (s.start_ms == start_ms && s.end_ms == end_ms) return s;
    }

    return {};
}

void RecordManager::dumpIndex() const
{
    std::cout << "\n=== dumpIndex() ===\n";

    for (const auto& kv : index_)
    {
        const auto& stream = kv.first;
        const auto& files = kv.second;

        std::cout << "\n>>> Stream = " << stream << ", file_count = " << files.size() << "\n";

        for (const auto& f : files)
        {
            std::cout << "  - " << f.path << "\n      start_ms=" << f.start_ms << ", end_ms=" << f.end_ms << "\n";
        }
    }
}