#ifndef command_manager_hh_INCLUDED
#define command_manager_hh_INCLUDED

#include "coord.hh"
#include "completion.hh"
#include "array_view.hh"
#include "shell_manager.hh"
#include "parameters_parser.hh"
#include "string.hh"
#include "optional.hh"
#include "utils.hh"
#include "hash_map.hh"

#include <functional>
#include <initializer_list>

namespace Kakoune
{

class Context;
using CommandParameters = ConstArrayView<String>;
using Command = std::function<void (const ParametersParser& parser,
                                    Context& context,
                                    const ShellContext& shell_context)>;

using CommandCompleter = std::function<Completions (const Context& context,
                                                    CompletionFlags,
                                                    CommandParameters,
                                                    size_t, ByteCount)>;

using CommandHelper = std::function<String (const Context& context, CommandParameters)>;

enum class CommandFlags
{
    None   = 0,
    Hidden = 1,
};
constexpr bool with_bit_ops(Meta::Type<CommandFlags>) { return true; }

struct CommandInfo { String name, info; };

struct Token
{
    enum class Type
    {
        Raw,
        RawQuoted,
        RawEval,
        ShellExpand,
        RegisterExpand,
        OptionExpand,
        ValExpand,
        ArgExpand,
        CommandSeparator
    };
    Token() : m_type(Type::Raw) {}

    Token(Type type, ByteCount b, ByteCount e, DisplayCoord coord, String str = "")
        : m_type(type), m_begin(b), m_end(e), m_coord(coord), m_content(std::move(str)) {}

    Type type() const { return m_type; }
    ByteCount begin() const { return m_begin; }
    ByteCount end() const { return m_end; }
    DisplayCoord coord() const { return m_coord; }
    const String& content() const { return m_content; }

private:
    Type   m_type;
    ByteCount m_begin;
    ByteCount m_end;
    DisplayCoord m_coord;
    String m_content;
};

using TokenList = Vector<Token>;

template<bool throw_on_unterminated>
TokenList parse(StringView line);

class CommandManager : public Singleton<CommandManager>
{
public:
    void execute(StringView command_line, Context& context,
                 const ShellContext& shell_context = ShellContext{});

    Completions complete(const Context& context, CompletionFlags flags,
                         StringView command_line, ByteCount cursor_pos);

    Completions complete(const Context& context, CompletionFlags flags,
                         CommandParameters params,
                         size_t token_to_complete, ByteCount pos_in_token);

    Optional<CommandInfo> command_info(const Context& context,
                                       StringView command_line) const;

    bool command_defined(StringView command_name) const;

    void register_command(String command_name, Command command,
                          String docstring,
                          ParameterDesc param_desc,
                          CommandFlags flags = CommandFlags::None,
                          CommandHelper helper = CommandHelper(),
                          CommandCompleter completer = CommandCompleter());

    Completions complete_command_name(const Context& context, StringView query) const;

    void clear_last_complete_command() { m_last_complete_command = String{}; }

private:
    void execute_single_command(CommandParameters params,
                                Context& context,
                                const ShellContext& shell_context,
                                DisplayCoord pos);

    struct CommandDescriptor
    {
        Command command;
        String docstring;
        ParameterDesc param_desc;
        CommandFlags flags;
        CommandHelper helper;
        CommandCompleter completer;
    };
    using CommandMap = HashMap<String, CommandDescriptor, MemoryDomain::Commands>;
    CommandMap m_commands;
    String m_last_complete_command;
    int m_command_depth = 0;

    CommandMap::const_iterator find_command(const Context& context,
                                            StringView name) const;
};

String expand(StringView str, const Context& context,
              const ShellContext& shell_context = ShellContext{});

String expand(StringView str, const Context& context,
              const ShellContext& shell_context,
              const std::function<String (String)>& postprocess);

}

#endif // command_manager_hh_INCLUDED