#include "face_registry.hh"

#include "exception.hh"
#include "ranges.hh"
#include "string_utils.hh"

namespace Kakoune
{

static FaceRegistry::FaceSpec parse_face(StringView facedesc)
{
    constexpr StringView invalid_face_error = "invalid face description, expected <fg>[,<bg>][+<attr>][@base] or just [base]";
    if (all_of(facedesc, [](char c){ return is_word(c); }) and not is_color_name(facedesc))
        return {Face{}, facedesc.str()};

    auto bg_it = find(facedesc, ',');
    auto attr_it = find(facedesc, '+');
    auto base_it = find(facedesc, '@');
    if (bg_it != facedesc.end()
        and (attr_it < bg_it or (bg_it + 1) == facedesc.end()))
        throw runtime_error(invalid_face_error.str());
    if (attr_it != facedesc.end()
        and (attr_it + 1) == facedesc.end())
        throw runtime_error(invalid_face_error.str());

    auto colors_end = std::min(attr_it, base_it);

    FaceRegistry::FaceSpec spec;
    auto& face = spec.face;
    face.fg = colors_end != facedesc.begin() ?
        str_to_color({facedesc.begin(), std::min(bg_it, colors_end)}) : Color::Default;
    if (bg_it != facedesc.end())
        face.bg = bg_it+1 != attr_it ? str_to_color({bg_it+1, colors_end}) : Color::Default;
    if (attr_it != facedesc.end())
    {
        for (++attr_it; attr_it != base_it; ++attr_it)
        {
            switch (*attr_it)
            {
                case 'u': face.attributes |= Attribute::Underline; break;
                case 'r': face.attributes |= Attribute::Reverse; break;
                case 'b': face.attributes |= Attribute::Bold; break;
                case 'B': face.attributes |= Attribute::Blink; break;
                case 'd': face.attributes |= Attribute::Dim; break;
                case 'i': face.attributes |= Attribute::Italic; break;
                case 'f': face.attributes |= Attribute::FinalFg; break;
                case 'g': face.attributes |= Attribute::FinalBg; break;
                case 'a': face.attributes |= Attribute::FinalAttr; break;
                case 'F': face.attributes |= Attribute::Final; break;
                default: throw runtime_error(format("no such face attribute: '{}'", StringView{*attr_it}));
            }
        }
    }
    if (base_it != facedesc.end())
        spec.base = String{base_it+1, facedesc.end()};
    return spec;
}

String to_string(Attribute attributes)
{
    if (attributes == Attribute::Normal)
        return "";

    struct Attr { Attribute attr; StringView name; }
    attrs[] {
        { Attribute::Underline, "u" },
        { Attribute::Reverse, "r" },
        { Attribute::Blink, "B" },
        { Attribute::Bold, "b" },
        { Attribute::Dim, "d" },
        { Attribute::Italic, "i" },
        { Attribute::Final, "F" },
        { Attribute::FinalFg, "f" },
        { Attribute::FinalBg, "g" },
        { Attribute::FinalAttr, "a" },
    };

    auto filteredAttrs = attrs |
                         filter([=](const Attr& a) { return attributes & a.attr; }) |
                         transform([](const Attr& a) { return a.name; });

    return accumulate(filteredAttrs, "+"_str, std::plus<>{});
}

String to_string(Face face)
{
    return format("{},{}{}", face.fg, face.bg, face.attributes);
}

Face FaceRegistry::operator[](StringView facedesc) const
{
    return resolve_spec(parse_face(facedesc));
}

Face FaceRegistry::resolve_spec(const FaceSpec& spec) const
{
    if (spec.base.empty())
        return spec.face;

    StringView base = spec.base;
    Face face = spec.face;
    for (auto* reg = this; reg != nullptr; reg = reg->m_parent.get())
    {
        auto it = reg->m_faces.find(base);
        if (it == reg->m_faces.end())
            continue;

        if (it->value.base.empty())
            return merge_faces(it->value.face, face);
        if (it->value.base != it->key)
            return merge_faces(reg->resolve_spec(it->value), face);
        else
        {
            face = merge_faces(it->value.face, face);
            base = it->value.base;
        }
    }
    return face;
}

void FaceRegistry::add_face(StringView name, StringView facedesc, bool override)
{
    if (not override and m_faces.find(name) != m_faces.end())
        throw runtime_error(format("face '{}' already defined", name));

    if (name.empty() or is_color_name(name) or
        any_of(name, [](char c){ return not is_word(c); }))
        throw runtime_error(format("invalid face name: '{}'", name));

    FaceSpec spec = parse_face(facedesc);
    auto it = m_faces.find(spec.base);
    if (spec.base == name and it != m_faces.end())
    {
        it->value.face = merge_faces(it->value.face, spec.face);
        it->value.base = spec.base;
        return;
    }

    while (it != m_faces.end() and not it->value.base.empty())
    {
        if (it->value.base == name)
            throw runtime_error("face cycle detected");
        it = m_faces.find(it->value.base);
    }
    m_faces[name] = std::move(spec);
}

void FaceRegistry::remove_face(StringView name)
{
    m_faces.remove(name);
}

FaceRegistry::FaceRegistry()
    : m_faces{
        { "Default", {Face{ Color::Default, Color::Default }} },
        { "PrimarySelection", {Face{ Color::White, Color::Blue }} },
        { "SecondarySelection", {Face{ Color::Black, Color::Blue }} },
        { "PrimaryCursor", {Face{ Color::Black, Color::White }} },
        { "SecondaryCursor", {Face{ Color::Black, Color::White }} },
        { "PrimaryCursorEol", {Face{ Color::Black, Color::Cyan }} },
        { "SecondaryCursorEol", {Face{ Color::Black, Color::Cyan }} },
        { "LineNumbers", {Face{ Color::Default, Color::Default }} },
        { "LineNumberCursor", {Face{ Color::Default, Color::Default, Attribute::Reverse }} },
        { "LineNumbersWrapped", {Face{ Color::Default, Color::Default, Attribute::Italic }} },
        { "MenuForeground", {Face{ Color::White, Color::Blue }} },
        { "MenuBackground", {Face{ Color::Blue, Color::White }} },
        { "MenuInfo", {Face{ Color::Cyan, Color::Default }} },
        { "Information", {Face{ Color::Black, Color::Yellow }} },
        { "Error", {Face{ Color::Black, Color::Red }} },
        { "StatusLine", {Face{ Color::Cyan, Color::Default }} },
        { "StatusLineMode", {Face{ Color::Yellow, Color::Default }} },
        { "StatusLineInfo", {Face{ Color::Blue, Color::Default }} },
        { "StatusLineValue", {Face{ Color::Green, Color::Default }} },
        { "StatusCursor", {Face{ Color::Black, Color::Cyan }} },
        { "Prompt", {Face{ Color::Yellow, Color::Default }} },
        { "MatchingChar", {Face{ Color::Default, Color::Default, Attribute::Bold }} },
        { "BufferPadding", {Face{ Color::Blue, Color::Default }} },
        { "Whitespace", {Face{ Color::Default, Color::Default, Attribute::FinalFg }} },
      }
{}

}