/*
* Copyright 2016 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/

#include "CommandSet.h"

#include "SkCanvas.h"
#include "SkTSort.h"

namespace sk_app {

static bool on_key_handler(Window::Key key, Window::InputState state, uint32_t modifiers,
                           void* userData) {
    CommandSet* cs = reinterpret_cast<CommandSet*>(userData);
    return cs->onKey(key, state, modifiers);
}

static bool on_char_handler(SkUnichar c, uint32_t modifiers, void* userData) {
    CommandSet* cs = reinterpret_cast<CommandSet*>(userData);
    return cs->onChar(c, modifiers);
}

CommandSet::CommandSet()
    : fHelpMode(kNone_HelpMode) {
    this->addCommand('h', "Overlays", "Show help screen", [this]() {
        switch (this->fHelpMode) {
            case kNone_HelpMode:
                this->fHelpMode = kGrouped_HelpMode;
                break;
            case kGrouped_HelpMode:
                this->fHelpMode = kAlphabetical_HelpMode;
                break;
            case kAlphabetical_HelpMode:
                this->fHelpMode = kNone_HelpMode;
                break;
        }
        fWindow->inval();
    });
}

void CommandSet::attach(Window* window) {
    fWindow = window;
    window->registerKeyFunc(on_key_handler, this);
    window->registerCharFunc(on_char_handler, this);
}

bool CommandSet::onKey(Window::Key key, Window::InputState state, uint32_t modifiers) {
    if (Window::kDown_InputState == state) {
        for (Command& cmd : fCommands) {
            if (Command::kKey_CommandType == cmd.fType && key == cmd.fKey) {
                cmd.fFunction();
                return true;
            }
        }
    }

    return false;
}

bool CommandSet::onChar(SkUnichar c, uint32_t modifiers) {
    for (Command& cmd : fCommands) {
        if (Command::kChar_CommandType == cmd.fType && c == cmd.fChar) {
            cmd.fFunction();
            return true;
        }
    }

    return false;
}

void CommandSet::addCommand(SkUnichar c, const char* group, const char* description,
                            std::function<void(void)> function) {
    fCommands.push_back(Command(c, group, description, function));
}

void CommandSet::addCommand(Window::Key k, const char* keyName, const char* group,
                            const char* description, std::function<void(void)> function) {
    fCommands.push_back(Command(k, keyName, group, description, function));
}

#if defined(SK_BUILD_FOR_WIN32)
    #define SK_strcasecmp   _stricmp
#else
    #define SK_strcasecmp   strcasecmp
#endif

bool CommandSet::compareCommandKey(const Command& first, const Command& second) {
    return SK_strcasecmp(first.fKeyName.c_str(), second.fKeyName.c_str()) < 0;
}

bool CommandSet::compareCommandGroup(const Command& first, const Command& second) {
    return SK_strcasecmp(first.fGroup.c_str(), second.fGroup.c_str()) < 0;
}

void CommandSet::drawHelp(SkCanvas* canvas) {
    if (kNone_HelpMode == fHelpMode) {
        return;
    }

    // Sort commands for current mode:
    SkTQSort(fCommands.begin(), fCommands.end() - 1,
             kAlphabetical_HelpMode == fHelpMode ? compareCommandKey : compareCommandGroup);

    SkPaint bgPaint;
    bgPaint.setColor(0xC0000000);
    canvas->drawPaint(bgPaint);

    SkPaint paint;
    paint.setTextSize(16);
    paint.setAntiAlias(true);
    paint.setColor(0xFFFFFFFF);

    SkPaint groupPaint;
    groupPaint.setTextSize(18);
    groupPaint.setUnderlineText(true);
    groupPaint.setAntiAlias(true);
    groupPaint.setColor(0xFFFFFFFF);

    SkScalar x = SkIntToScalar(10);
    SkScalar y = SkIntToScalar(10);

    // Measure all key strings:
    SkScalar keyWidth = 0;
    for (Command& cmd : fCommands) {
        keyWidth = SkMaxScalar(keyWidth,
                               paint.measureText(cmd.fKeyName.c_str(), cmd.fKeyName.size()));
    }
    keyWidth += paint.measureText(" ", 1);

    // If we're grouping by category, we'll be adding text height on every new group (including the
    // first), so no need to do that here. Otherwise, skip down so the first line is where we want.
    if (kGrouped_HelpMode != fHelpMode) {
        y += paint.getTextSize();
    }

    // Print everything:
    SkString lastGroup;
    for (Command& cmd : fCommands) {
        if (kGrouped_HelpMode == fHelpMode && lastGroup != cmd.fGroup) {
            // Group change. Advance and print header:
            y += paint.getTextSize();
            canvas->drawText(cmd.fGroup.c_str(), cmd.fGroup.size(), x, y, groupPaint);
            y += groupPaint.getTextSize() + 2;
            lastGroup = cmd.fGroup;
        }

        canvas->drawText(cmd.fKeyName.c_str(), cmd.fKeyName.size(), x, y, paint);
        SkString text = SkStringPrintf(": %s", cmd.fDescription.c_str());
        canvas->drawText(text.c_str(), text.size(), x + keyWidth, y, paint);
        y += paint.getTextSize() + 2;
    }
}

}   // namespace sk_app