#include "NDSUI.hpp"
#include "font.h"

#include <exception>
#include <gl2d.h>
#include <nds.h>
#include <nds/touch.h>
#include <nds/input.h>

#define SCREEN_BORDER_PADDING 3
#define FONT_PADDING 1
#define INPUT_LINE_HEIGHT (FONT_HEIGHT+FONT_PADDING)
#define LOG_LINE_PADDING 5


NDSUI *NDSUI::currentInstance;



consteval
unsigned NDSUI::calcMaxCharsInLine(unsigned int width) {
    return width / (FONT_WIDTH + FONT_PADDING) - 1;
}
consteval
unsigned NDSUI::calcMaxLinesInRow(unsigned height) {
    return height / (FONT_HEIGHT + FONT_PADDING);
}

void NDSUI::kbCallback(int key) {
    if (key > 0) currentInstance->handleInput(static_cast<char>(key));
}

consteval
Box2D NDSUI::calcMessageLogDimensions() {
    return {
        {SCREEN_BORDER_PADDING, 0},
        {SCREEN_WIDTH-SCREEN_BORDER_PADDING, SCREEN_HEIGHT-(SCREEN_BORDER_PADDING*2)-INPUT_LINE_HEIGHT}
    };
}
void NDSUI::renderMessageLog() {
    constexpr Box2D boxDims = calcMessageLogDimensions();

    // Draw box
    glBoxFilled(boxDims.topLeft.x, boxDims.topLeft.y, boxDims.bottomRight.x, boxDims.bottomRight.y, RGB15(6, 2, 14));

    // Log messages renderer
    auto renderLine = [this, y = int(boxDims.bottomRight.y - FONT_PADDING - FONT_HEIGHT), boxDims] (std::string_view line) mutable {
        // Skip empty lines
        if (line.empty()) return true;
        // Check if line is bold
        bool bold = line[0] == '\t';
        if (bold) {
            line = {line.data()+1, line.size()-1};
        }
        // Print line itself
        print(line, {boxDims.topLeft.x + FONT_PADDING, unsigned(y)}, RGB15(28, 28, 28), bold);
        // Go to next line
        y -= FONT_PADDING * LOG_LINE_PADDING + FONT_HEIGHT;
        // Stop rendering any more lines
        return y >= 0;
    };

    // Display line by line
    unsigned lineCount = 0;
    for (auto message = messages.rbegin(); message != messages.rend(); message++) {
        const auto& lines = message->getLines();
        for (auto line = lines.rbegin(); line != lines.rend(); line++) {
            if (lineCount >= scrollOff)
                if (!renderLine(*line))
                    return;
            lineCount++;
        }
    }
}

consteval
Box2D NDSUI::calcInputLineDimensions() {
    return {
        {SCREEN_BORDER_PADDING, SCREEN_HEIGHT-SCREEN_BORDER_PADDING-INPUT_LINE_HEIGHT},
        {SCREEN_WIDTH-SCREEN_BORDER_PADDING, SCREEN_HEIGHT-SCREEN_BORDER_PADDING}
    };
}
void NDSUI::renderInputLine() {
    constexpr Box2D boxDims = calcInputLineDimensions();
    constexpr Position2D textTopLeft{boxDims.topLeft.x+FONT_PADDING, boxDims.topLeft.y+FONT_PADDING};

    // Draw box
    glBoxFilled(boxDims.topLeft.x, boxDims.topLeft.y, boxDims.bottomRight.x, boxDims.bottomRight.y, RGB15(13, 8, 3));

    // Measure amount of character that fit in
    constexpr auto maxChars = calcMaxCharsInLine(boxDims.bottomRight.x - boxDims.topLeft.x);

    // Mease amount of characters that don't fit in
    unsigned startIdx = 0;
    if (inputLineBufHead > maxChars) {
        startIdx = inputLineBufHead - maxChars;
    }

    // Get that amount of characters
    print(&inputLineBuf[startIdx], textTopLeft, RGB15(28, 28, 28));
}

bool NDSUI::printChar(const char character, Position2D *topleftpos, const int color, bool bold) {
    const bool *fontChar = font_get_character(character);
    int y = 0;
    int x = 0;
    unsigned row = 0;
    unsigned y_start = 0;
    for (const bool *thispixel = fontChar; ; thispixel++) {
        if (y == FONT_HEIGHT) {
            y = 0;
            x++;
        } if (x == FONT_WIDTH) {
            break;
        } if (*thispixel) {
            if (row == 0) y_start = y;
            row++;
        } else if (row) {
            if (row >= 3 || boxesRendered < 1000 || ((x&1) || (y&1))) {
                glBoxFilled(topleftpos->x + x, topleftpos->y + y_start, topleftpos->x + x, topleftpos->y + y - (!bold)*1, color);
                boxesRendered++;
            }
            row = 0;
        }
        ++y;
    }
    return fontChar != fontBitmapUnk;
}

void NDSUI::print(std::string_view str, Position2D topleftpos, const int color, bool bold) {
    for (const char c : str) {
        printChar(c, &topleftpos, color, bold);
        topleftpos.x += FONT_WIDTH + FONT_PADDING;
    }
}

void NDSUI::handleInput(char c) {
    //TODO: Check length
    switch (c) {
    case '\b': {
        // Remove character if not at start
        if (inputLineBufHead != 0) {
            inputLineBuf[--inputLineBufHead] = '\0';
        }
    } break;
    case '\n': {
        if (userInputHandler && inputLineBuf[0]) {
            auto msg = createLogMessage("User", inputLineBuf.data());
            addLogMessage(std::move(msg));
            userInputHandler->set(inputLineBuf.data());
            resetInputLine();
            scrollOff = 0;
            //userInputHandler = nullptr;
        }
    } break;
    default: {
        // Add character if not at end
        if (inputLineBufHead != inputLineBuf.size() - 1) {
            inputLineBuf[inputLineBufHead] = c;
            inputLineBuf[++inputLineBufHead] = '\0';
        }
    }
    }
}

void NDSUI::scanButtons() {
    scanKeys();
    int keys = keysDownRepeat();
    // Scrolling
    if (scrollOff != 0) {
        if (keys & KEY_DOWN) {
            scrollOff -= 1;
        } else if (keys & KEY_RIGHT) {
            scrollOff -= 5;
        }
    }
    if (keys & KEY_UP) {
        scrollOff += 1;
    } else if (keys & KEY_LEFT) {
        scrollOff += 5;
    }
}

NDSUI::NDSUI() {
    resetInputLine();
    glScreen2D();
    auto swkbd = keyboardDemoInit();
    swkbd->OnKeyReleased = kbCallback;
    keyboardShow();
}

void NDSUI::run() {
    currentInstance = this;
    boxesRendered = 0;
    // Update buttons
    scanButtons();
    // Update keyboard
    keyboardUpdate();
    // Draw
    glBegin2D(); {
        renderInputLine();
        renderMessageLog();
    } glEnd2D();
    // Apply changes
    glFlush(0);
    swiWaitForVBlank();
}

LineWrappedString NDSUI::createLogMessage(const char *username, std::string_view message) {
    // Do line-wrapping, create and return Message instance
    return LineWrappedString("\t "+std::string(username)+"\n"+std::string(message)+"\n", calcMaxCharsInLine(calcMessageLogDimensions().width()));
}

void LineWrappedString::split(std::string_view str, unsigned maxCharsPerLine) {
    lines.clear();
    const char *currStrStart = str.data();
    const char *strEnd = str.data() + str.size();
    for (size_t currStrLen = 0; ;) {
        const char& c = currStrStart[currStrLen];
        bool brk = false;
        bool next = false;
        bool minusOne = false;
        if (c == '\n') {
            next = true;
            minusOne = true;
        } else if (&c == strEnd) {
            next = true;
            brk = true;
            minusOne = true;
        } else if (currStrLen > maxCharsPerLine) {
            next = true;
        }

        if (next) {
            lines.push_back({currStrStart, currStrLen});
            if (brk) break;

            currStrStart += currStrLen + minusOne;
            currStrLen = 0;
        } else {
            currStrLen++;
        }
    }
}