analysis.cppm

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// BSD 3-Clause License
// Copyright (c) 2025, 🍀☀🌕🌥 🌊
// See the LICENSE file in the project root for full license information.
 
export module kcenon.logger:analysis;
 
// Standard library imports
import <chrono>;
import <memory>;
import <string>;
import <unordered_map>;
import <vector>;
 
// Import core partition for types
import :core;
 
export namespace kcenon::logger::analysis {
 
struct analyzed_log_entry {
    common::interfaces::log_level level;
    std::string message;
    std::chrono::system_clock::time_point timestamp;
    std::string source_file;
    int source_line;
    std::string function_name;
};
 
struct analysis_stats {
    size_t total_entries = 0;
    std::unordered_map<common::interfaces::log_level, size_t> level_counts;
    std::chrono::system_clock::time_point earliest_timestamp;
    std::chrono::system_clock::time_point latest_timestamp;
    std::vector<std::string> most_frequent_messages;
    std::unordered_map<std::string, size_t> error_patterns;
};
 
class log_analyzer {
private:
    std::vector<analyzed_log_entry> entries_;
    analysis_stats cached_stats_;
    bool stats_dirty_ = true;
 
public:
    void add_entry(const analyzed_log_entry& entry) {
        entries_.push_back(entry);
        stats_dirty_ = true;
    }
 
    void add_entries(const std::vector<analyzed_log_entry>& entries) {
        entries_.insert(entries_.end(), entries.begin(), entries.end());
        stats_dirty_ = true;
    }
 
    void clear() {
        entries_.clear();
        cached_stats_ = analysis_stats{};
        stats_dirty_ = true;
    }
 
    const analysis_stats& get_stats() {
        if (stats_dirty_) {
            update_stats();
            stats_dirty_ = false;
        }
        return cached_stats_;
    }
 
    std::vector<analyzed_log_entry> filter_by_level(common::interfaces::log_level level) const {
        std::vector<analyzed_log_entry> filtered;
        for (const auto& entry : entries_) {
            if (entry.level == level) {
                filtered.push_back(entry);
            }
        }
        return filtered;
    }
 
    std::vector<analyzed_log_entry> filter_by_time_range(
        const std::chrono::system_clock::time_point& start,
        const std::chrono::system_clock::time_point& end) const {
 
        std::vector<analyzed_log_entry> filtered;
        for (const auto& entry : entries_) {
            if (entry.timestamp >= start && entry.timestamp <= end) {
                filtered.push_back(entry);
            }
        }
        return filtered;
    }
 
    std::vector<analyzed_log_entry> search_messages(const std::string& search_text) const {
        std::vector<analyzed_log_entry> results;
        for (const auto& entry : entries_) {
            if (entry.message.find(search_text) != std::string::npos) {
                results.push_back(entry);
            }
        }
        return results;
    }
 
    double get_error_rate(const std::chrono::minutes& window = std::chrono::minutes(60)) const {
        auto now = std::chrono::system_clock::now();
        auto start_time = now - window;
 
        size_t total_in_window = 0;
        size_t errors_in_window = 0;
 
        for (const auto& entry : entries_) {
            if (entry.timestamp >= start_time) {
                total_in_window++;
                if (entry.level == common::interfaces::log_level::error ||
                    entry.level == common::interfaces::log_level::critical) {
                    errors_in_window++;
                }
            }
        }
 
        return total_in_window > 0 ?
            static_cast<double>(errors_in_window) / static_cast<double>(total_in_window) : 0.0;
    }
 
    std::string generate_summary_report() {
        const auto& stats = get_stats();
 
        std::string report = "=== Log Analysis Summary ===\n";
        report += "Total Entries: " + std::to_string(stats.total_entries) + "\n";
        report += "Level Distribution:\n";
 
        for (const auto& [level, count] : stats.level_counts) {
            report += "  " + level_to_string(level) + ": " + std::to_string(count) + "\n";
        }
 
        if (stats.total_entries > 0) {
            auto duration = std::chrono::duration_cast<std::chrono::minutes>(
                stats.latest_timestamp - stats.earliest_timestamp);
            report += "Time Range: " + std::to_string(duration.count()) + " minutes\n";
        }
 
        return report;
    }
 
    size_t size() const {
        return entries_.size();
    }
 
    bool empty() const {
        return entries_.empty();
    }
 
private:
    void update_stats() {
        cached_stats_ = analysis_stats{};
        cached_stats_.total_entries = entries_.size();
 
        if (entries_.empty()) {
            return;
        }
 
        // Initialize timestamps
        cached_stats_.earliest_timestamp = entries_[0].timestamp;
        cached_stats_.latest_timestamp = entries_[0].timestamp;
 
        // Count levels and update timestamps
        for (const auto& entry : entries_) {
            cached_stats_.level_counts[entry.level]++;
 
            if (entry.timestamp < cached_stats_.earliest_timestamp) {
                cached_stats_.earliest_timestamp = entry.timestamp;
            }
            if (entry.timestamp > cached_stats_.latest_timestamp) {
                cached_stats_.latest_timestamp = entry.timestamp;
            }
        }
    }
 
    std::string level_to_string(common::interfaces::log_level level) const {
        // Use underlying integer to avoid duplicate case value errors
        // (warn and warning both = 3, fatal and critical both = 5)
        const int level_value = static_cast<int>(level);
        switch (level_value) {
            case 0: return "TRACE";
            case 1: return "DEBUG";
            case 2: return "INFO";
            case 3: return "WARN";
            case 4: return "ERROR";
            case 5: return "FATAL";
            case 6: return "OFF";
            default: return "UNKNOWN";
        }
    }
};
 
class analyzer_factory {
public:
    static std::unique_ptr<log_analyzer> create_basic() {
        return std::make_unique<log_analyzer>();
    }
};
 
} // namespace kcenon::logger::analysis