From 95fedfa3a3bf21203413e3e2a87a1d700333f158 Mon Sep 17 00:00:00 2001
From: MihailRis <mexaruc@gmail.com>
Date: Mon, 8 Apr 2024 03:17:44 +0300
Subject: [PATCH] packs manager (unused yet)

---
 src/content/PacksManager.cpp | 131 +++++++++++++++++++++++++++++++++++
 src/content/PacksManager.h   |  36 ++++++++++
 src/util/listutil.h          |   9 ++-
 3 files changed, 175 insertions(+), 1 deletion(-)
 create mode 100644 src/content/PacksManager.cpp
 create mode 100644 src/content/PacksManager.h

diff --git a/src/content/PacksManager.cpp b/src/content/PacksManager.cpp
new file mode 100644
index 00000000..6ff3a020
--- /dev/null
+++ b/src/content/PacksManager.cpp
@@ -0,0 +1,131 @@
+#include "PacksManager.h"
+
+#include "../util/listutil.h"
+
+#include <queue>
+#include <sstream>
+
+PacksManager::PacksManager() {
+}
+
+void PacksManager::setSources(std::vector<fs::path> sources) {
+    this->sources = sources;
+}
+
+void PacksManager::scan() {
+    packs.clear();
+    
+    std::vector<ContentPack> packsList;
+    for (auto& folder : sources) {
+        ContentPack::scanFolder(folder, packsList);
+        for (auto& pack : packsList) {
+            packs.emplace(pack.id, pack);
+        }
+    }
+}
+
+std::vector<std::string> PacksManager::getAllNames() {
+    std::vector<std::string> names;
+    for (auto& entry : packs) {
+        names.push_back(entry.first);
+    }
+    return names;
+}
+
+static contentpack_error on_circular_dependency(std::queue<ContentPack*>& queue) {
+    ContentPack* lastPack = queue.back();
+    // circular dependency
+    std::stringstream ss;
+    ss << "circular dependency: " << lastPack->id;
+    while (!queue.empty()) {
+        auto* pack = queue.front();
+        queue.pop();
+        ss << " <- " << pack->id;
+    }
+    return contentpack_error(lastPack->id, lastPack->folder, ss.str());
+}
+
+/// @brief Resolve pack dependencies
+/// @param pack current pack
+/// @param packs all available packs repository
+/// @param allNames all already done or enqueued packs
+/// @param added packs with all dependencies resolved
+/// @param queue current pass queue
+/// @param resolveWeaks make weak dependencies resolved if found but not added to queue
+/// @return true if all dependencies are already added or not found (optional/weak)
+/// @throws contentpack_error if required dependency is not found
+static bool resolve_dependencies (
+    ContentPack* pack,
+    std::unordered_map<std::string, ContentPack>& packs,
+    std::vector<std::string>& allNames,
+    std::vector<std::string>& added,
+    std::queue<ContentPack*>& queue,
+    bool resolveWeaks
+) {
+    bool satisfied = true;
+    for (auto& dep : pack->dependencies) {
+        if (util::contains(added, dep.id)) {
+            continue;
+        }
+        auto found = packs.find(dep.id);
+        bool exists = found != packs.end();
+        if (!exists && dep.level == DependencyLevel::required) {
+            throw contentpack_error(pack->id, pack->folder, "missing dependency '"+dep.id+"'");
+        }
+        if (!exists) {
+            // ignored for optional or weak dependencies
+            continue;
+        }
+        if (resolveWeaks && dep.level == DependencyLevel::weak) {
+            // dependency pack is found but not added yet
+            // resolveWeaks is used on second iteration, so it's will not be added
+            continue;
+        }
+
+        if (!util::contains(allNames, dep.id) && dep.level != DependencyLevel::weak) { 
+            allNames.push_back(dep.id);
+            queue.push(&found->second);
+        }
+        satisfied = false;
+    }
+    return satisfied;
+}
+
+std::vector<std::string> PacksManager::assembly(const std::vector<std::string>& names) {
+    std::vector<std::string> allNames = names;
+    std::vector<std::string> added;
+    std::queue<ContentPack*> queue;
+    std::queue<ContentPack*> queue2;
+
+    for (auto& name : names) {
+        auto found = packs.find(name);
+        if (found == packs.end()) {
+            throw contentpack_error(name, fs::path(""), "pack not found");
+        }
+        queue.push(&found->second);
+    }
+
+    bool resolveWeaks = false;
+    while (!queue.empty()) {
+        int addedInIteration = 0;
+        while (!queue.empty()) {
+            auto* pack = queue.front();
+            queue.pop();
+            
+            if (resolve_dependencies(pack, packs, allNames, added, queue, resolveWeaks)) {
+                added.push_back(pack->id);
+                addedInIteration++;
+            } else {
+                queue2.push(pack);
+            }
+        }
+        std::swap(queue, queue2);
+
+        // nothing done but deferring
+        if (addedInIteration == 0 && resolveWeaks) {
+            throw on_circular_dependency(queue);
+        }
+        resolveWeaks = true;
+    }
+    return added;
+}
diff --git a/src/content/PacksManager.h b/src/content/PacksManager.h
new file mode 100644
index 00000000..96071e01
--- /dev/null
+++ b/src/content/PacksManager.h
@@ -0,0 +1,36 @@
+#ifndef CONTENT_PACKS_MANAGER_H_
+#define CONTENT_PACKS_MANAGER_H_
+
+#include "ContentPack.h"
+
+#include <vector>
+#include <filesystem>
+#include <unordered_map>
+
+namespace fs = std::filesystem;
+
+class PacksManager {
+    std::unordered_map<std::string, ContentPack> packs;
+    std::vector<fs::path> sources;
+public:
+    PacksManager();
+
+    /// @brief Set content packs sources (search folders)
+    void setSources(std::vector<fs::path> sources);
+
+    /// @brief Scan sources and collect all found packs excluding duplication.
+    /// Scanning order depends on sources order
+    void scan();
+
+    /// @brief Get all found packs
+    std::vector<std::string> getAllNames();
+
+    /// @brief Resolve all dependencies and fix packs order
+    /// @param names required packs (method can add extra packs)
+    /// @return resulting ordered vector of pack names
+    /// @throws contentpack_error if required dependency not found or
+    /// circular dependency detected
+    std::vector<std::string> assembly(const std::vector<std::string>& names);
+};
+
+#endif // CONTENT_PACKS_MANAGER_H_
diff --git a/src/util/listutil.h b/src/util/listutil.h
index 1ed07d2f..911aacba 100644
--- a/src/util/listutil.h
+++ b/src/util/listutil.h
@@ -1,13 +1,20 @@
 #ifndef UTIL_LISTUTIL_H_
 #define UTIL_LISTUTIL_H_
 
+#include <algorithm>
 #include <vector>
+#include <queue>
 
 namespace util {
     template<class T>
-    bool contains(std::vector<T> vec, const T& value) {
+    bool contains(const std::vector<T>& vec, const T& value) {
         return std::find(vec.begin(), vec.end(), value) != vec.end();
     }
+
+    template<class T>
+    bool contains(const std::queue<T>& queue, const T& value) {
+        return std::find(queue.begin(), queue.end(), value) != queue.end();
+    }
 }
 
 #endif // UTIL_LISTUTIL_H_