#ifndef command_manager_hh_INCLUDED
#define command_manager_hh_INCLUDED

#include <unordered_map>
#include <functional>
#include <initializer_list>

#include "string.hh"
#include "utils.hh"
#include "completion.hh"
#include "memoryview.hh"
#include "shell_manager.hh"

namespace Kakoune
{

struct Context;

struct wrong_argument_count : runtime_error
{
    wrong_argument_count() : runtime_error("wrong argument count") {}
};

using CommandParameters = memoryview<String>;

typedef std::function<void (const CommandParameters&,
                            Context& context)> Command;

typedef std::function<CandidateList (const Context& context,
                                     const CommandParameters&,
                                     size_t, CharCount)> CommandCompleter;

class PerArgumentCommandCompleter
{
public:
    typedef std::function<CandidateList (const Context&,
                                         const String&, CharCount)> ArgumentCompleter;
    typedef memoryview<ArgumentCompleter> ArgumentCompleterList;

    PerArgumentCommandCompleter(const ArgumentCompleterList& completers)
        : m_completers(completers.begin(), completers.end()) {}

    CandidateList operator()(const Context& context,
                             const CommandParameters& params,
                             size_t token_to_complete,
                             CharCount pos_in_token) const;

private:
    std::vector<ArgumentCompleter> m_completers;
};

class CommandManager : public Singleton<CommandManager>
{
public:
    void execute(const String& command_line, Context& context,
                 const EnvVarMap& env_vars = EnvVarMap());

    Completions complete(const Context& context,
                         const String& command_line, CharCount cursor_pos);

    bool command_defined(const String& command_name) const;

    void register_command(const String& command_name,
                          Command command,
                          const CommandCompleter& completer = CommandCompleter());

    void register_commands(const memoryview<String>& command_names,
                           Command command,
                           const CommandCompleter& completer = CommandCompleter());

private:
    void execute_single_command(const CommandParameters& params,
                                Context& context) const;
    struct CommandDescriptor
    {
        Command command;
        CommandCompleter completer;
    };
    std::unordered_map<String, CommandDescriptor> m_commands;
};

}

#endif // command_manager_hh_INCLUDED