command_tree.h

/*
 * Copyright 2025 Dominik Czekai
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
 
#pragma once
#include <iostream>
#include <memory>
#include <stdexcept>
#include <string_view>
#include <unordered_map>
 
#include "command.h"
 
namespace cli::commands
{
 
class CommandNotFoundException : public std::runtime_error
{
public:
    CommandNotFoundException(const std::string &missingId, const std::vector<std::string> &chain)
        : std::runtime_error(buildMessage(missingId, chain)), missing(missingId), path(chain)
    {
    }
 
    const std::string &missingId() const noexcept { return missing; }
 
    const std::vector<std::string> &insertChain() const noexcept { return path; }
 
private:
    std::string missing;
    std::vector<std::string> path;
 
    static std::string buildMessage(const std::string &id, const std::vector<std::string> &chain);
};
 
class CommandTree
{
public:
    explicit CommandTree(std::string_view rootName);
 
    template <typename... Ids>
    void insert(std::unique_ptr<Command> cmd, std::string_view parentId, Ids &&...rest)
    {
        Command *parentCommandPtr = find(parentId, std::forward<Ids>(rest)...);
        if (!parentCommandPtr)
        {
            std::vector<std::string> chain{std::string(parentId), std::string(rest)...};
            throw CommandNotFoundException(std::string(parentId), chain);
        }
 
        parentCommandPtr->withSubCommand(std::move(cmd));
    }
 
    void insert(std::unique_ptr<Command> cmd) // insert at root
    {
        root->withSubCommand(std::move(cmd));
    }
 
    template <typename... Ids> Command *find(Ids &&...ids) const
    {
        return findRecursive(root.get(), std::forward<Ids>(ids)...);
    }
 
    void forEachCommand(const std::function<void(Command *)> &func) const
    {
        if (root)
        {
            forEachCommandRecursive(root.get(), func);
        }
    }
 
    void forEachCommand(const std::function<void(Command &)> &func) const
    {
        if (root)
        {
            forEachCommandRecursive(root.get(), func);
        }
    }
 
    Command *getRootCommand() { return root.get(); }
 
    const Command *getRootCommand() const { return root.get(); }
 
    std::string_view getPathForCommand(Command *cmd) const;
 
    void buildCommandPathMap(const std::string &separator = " ");
 
    std::vector<Command *> getAllCommands() const;
 
    std::vector<const Command *> getAllCommandsConst() const;
 
private:
    std::unique_ptr<Command> root;
    std::unordered_map<Command *, std::string> commandPathMap;
 
    void buildCommandPathMapRecursive(Command *cmd, std::vector<std::string> &path,
                                      const std::string &separator);
 
    // Recursive finder
    template <typename... Ids>
    static Command *findRecursive(Command *cmdPtr, std::string_view id, Ids &&...rest)
    {
        auto it = cmdPtr->getSubCommands().find(std::string(id));
        if (it == cmdPtr->getSubCommands().end())
            return nullptr;
 
        Command *subCommandPtr = it->second.get();
 
        if constexpr (sizeof...(rest) == 0)
        {
            // Base case: no more ids, return the child
            return subCommandPtr;
        }
        // Recursive case: continue with remaining ids
        return findRecursive(subCommandPtr, std::forward<Ids>(rest)...);
    }
 
    static Command *findRecursive(Command *cmdPtr) { return cmdPtr; }
 
    // Recursive DFS helper
    static void forEachCommandRecursive(Command *cmdPtr, const std::function<void(Command *)> &func)
    {
        if (cmdPtr)
        {
            func(cmdPtr); // call user-provided function
            for (const auto &[key, subCommandPtr] : cmdPtr->getSubCommands())
            {
                forEachCommandRecursive(subCommandPtr.get(), func);
            }
        }
    }
 
    static void forEachCommandRecursive(Command *cmdPtr, const std::function<void(Command &)> &func)
    {
        if (cmdPtr)
        {
            func(*cmdPtr); // call user-provided function
            for (const auto &[key, subCommandPtr] : cmdPtr->getSubCommands())
            {
                forEachCommandRecursive(subCommandPtr.get(), func);
            }
        }
    }
 
    // Helper function to collect all commands into a vector
    static void getAllCommandsRecursive(Command *cmdPtr, std::vector<Command *> &commands)
    {
        if (cmdPtr)
        {
            commands.push_back(cmdPtr);
            for (const auto &[key, subCommandPtr] : cmdPtr->getSubCommands())
            {
                getAllCommandsRecursive(subCommandPtr.get(), commands);
            }
        }
    }
 
    // Helper function to collect all commands into a vector (const version)
    static void getAllCommandsRecursive(const Command *cmdPtr, std::vector<const Command *> &commands)
    {
        if (cmdPtr)
        {
            commands.push_back(cmdPtr);
            for (const auto &[key, subCommandPtr] : cmdPtr->getSubCommands())
            {
                getAllCommandsRecursive(subCommandPtr.get(), commands);
            }
        }
    }
};
} // namespace cli::commands