// SPDX-License-Identifier: LGPL-3.0-only
// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®

module Crafter.Debug:Timeline_impl;
import std;
import Crafter.Debug.Core;
import :Registry;
import :Timeline;

using namespace Crafter::Debug;
using namespace Crafter::Debug::Detail;

namespace {
    constexpr std::size_t capacity = 8192;

    bool Stored(std::uint64_t failures) {
        return failures <= 10 || std::has_single_bit(failures);
    }
}

std::string_view Crafter::Debug::EntryKindName(EntryKind kind) {
    switch (kind) {
    case EntryKind::Log: return "log";
    case EntryKind::Warn: return "warn";
    case EntryKind::Error: return "error";
    case EntryKind::Check: return "check";
    case EntryKind::Event: return "event";
    case EntryKind::Agent: return "agent";
    case EntryKind::Pause: return "pause";
    case EntryKind::Stdio: return "stdio";
    }
    return "unknown";
}

std::uint8_t Crafter::Debug::Detail::Level(EntryKind kind) {
    switch (kind) {
    case EntryKind::Warn: return 1;
    case EntryKind::Error:
    case EntryKind::Check: return 2;
    default: return 0;
    }
}

TimelineEntry Crafter::Debug::Detail::MakeEntry(EntryKind kind, std::string_view category, std::string message, const std::source_location& location, Value payload) {
    TimelineEntry entry;
    entry.kind = kind;
    entry.category = std::string(category);
    entry.message = std::move(message);
    entry.file = location.file_name();
    entry.line = location.line();
    entry.payload = std::move(payload);
    return entry;
}

Timeline& Timeline::Instance() {
    static Timeline timeline;
    return timeline;
}

std::uint64_t Timeline::Append(TimelineEntry entry) {
    entry.frame = CurrentFrame();
    {
        std::lock_guard lock(mutex);
        entry.seconds = std::chrono::duration<double>(std::chrono::steady_clock::now() - start).count();
        entry.sequence = nextSequence++;
        entries.push_back(entry);
        if (entries.size() > capacity) entries.pop_front();
    }
    Notify(entry);
    return entry.sequence;
}

void Timeline::RecordCheck(std::string_view category, std::string message, const std::source_location& location) {
    TimelineEntry entry = MakeEntry(EntryKind::Check, category, std::move(message), location);
    entry.frame = CurrentFrame();
    {
        std::lock_guard lock(mutex);
        entry.seconds = std::chrono::duration<double>(std::chrono::steady_clock::now() - start).count();
        SiteCount& site = checks[{ entry.file, entry.line }];
        site.category = entry.category;
        entry.count = ++site.failures;
        if (Stored(entry.count)) {
            entry.sequence = nextSequence++;
            entries.push_back(entry);
            if (entries.size() > capacity) entries.pop_front();
        }
    }
    Notify(entry);
}

bool Crafter::Debug::Detail::Matches(const TimelineQuery& query, const TimelineEntry& entry) {
    if (entry.sequence <= query.afterSequence) return false;
    if (query.sinceFrame && entry.frame < *query.sinceFrame) return false;
    if (Level(entry.kind) < query.minLevel) return false;
    if (!query.kinds.empty() && std::ranges::find(query.kinds, entry.kind) == query.kinds.end()) return false;
    if (!query.category.empty() && !GlobMatch(query.category, entry.category)) return false;
    if (!query.grep.empty() && entry.message.find(query.grep) == std::string::npos && entry.category.find(query.grep) == std::string::npos) return false;
    return true;
}

std::vector<TimelineEntry> Timeline::Query(const TimelineQuery& query) const {
    std::vector<TimelineEntry> matched;
    std::lock_guard lock(mutex);
    for (const TimelineEntry& entry : entries) {
        if (Matches(query, entry)) matched.push_back(entry);
    }
    if (query.last != 0 && matched.size() > query.last) matched.erase(matched.begin(), matched.end() - static_cast<std::ptrdiff_t>(query.last));
    return matched;
}

std::uint64_t Timeline::LastSequence() const {
    std::lock_guard lock(mutex);
    return nextSequence - 1;
}

std::vector<CheckSite> Timeline::CheckSites() const {
    std::lock_guard lock(mutex);
    std::vector<CheckSite> sites;
    for (const auto& [site, count] : checks) sites.push_back({ site.first, site.second, count.category, count.failures });
    return sites;
}

void Timeline::SetListener(std::function<void(const TimelineEntry&)> callback) {
    std::lock_guard lock(mutex);
    listener = callback ? std::make_shared<const std::function<void(const TimelineEntry&)>>(std::move(callback)) : nullptr;
}

void Timeline::Notify(const TimelineEntry& entry) const {
    std::shared_ptr<const std::function<void(const TimelineEntry&)>> current;
    {
        std::lock_guard lock(mutex);
        current = listener;
    }
    if (current) (*current)(entry);
}