#include "UI.h"
#include <raylib.h>

const int MAX_LINES = 256;
const int SPACING_H = 1;
const float SCROLL_SENC = 10;

void DrawRecBordered(Rectangle rec, Color bg, Color border_color, int border_width) {
    DrawRectangleRounded(rec, 0.015f, 8, bg); 
    DrawRectangleRoundedLinesEx(rec, 0.015f, 8, border_width, border_color);
}

float MeasureChar(Font *font, int height, char symbol) {
    char buf[2] = { symbol, 0 };
    return MeasureTextEx(*font, buf, height, SPACING_H).x;
}

int CalculateSpans(Rectangle rec, char *text, Font *font, int height, int *spans) {
    spans[0] = 0;
    int ptr = 0, span_ptr = 1, last_space_ptr;
    float acc = 0;
    while (text[ptr] != 0x0) {
        char symbol = text[ptr];
        float char_width = MeasureChar(font, height, symbol);
        acc += char_width + SPACING_H;
        if (symbol == ' ' || symbol == '\n') last_space_ptr = ptr;
        if (acc > rec.width || symbol == '\n') {
            spans[span_ptr] = last_space_ptr + 1;
            ptr = last_space_ptr;
            span_ptr++;
            acc = 0;
        }
        ptr++;
    }
    return span_ptr + 1;
}

bool IsMouseInRec(Rectangle rec) {
    Vector2 MousePos = GetMousePosition();
    return CheckCollisionPointRec(MousePos, rec);
}

void DrawTextInRec(Rectangle rec, char *text, Font *font, int height, Color color, float padding, int *scroll) {
    int spans[MAX_LINES];
    rec.x += padding;
    rec.y += padding;
    rec.width -= 2 * padding;
    rec.height -= 2 * padding;
    int lines = CalculateSpans(rec, text, font, height, spans);

    if (lines == 2) {
        Vector2 pos = {.x = rec.x, .y = rec.y};
        DrawTextEx(*font, text, pos, height, SPACING_H, color);
        return;
    }

    int vertical_acc = rec.y - *scroll;
    int text_height = lines * height;
    int max_scroll = text_height - rec.height;

    if (text_height >= rec.height && IsMouseInRec(rec)) {
        *scroll -= GetMouseWheelMove() * SCROLL_SENC;
        if (*scroll < 0) *scroll = 0;
        if (*scroll > max_scroll) *scroll = max_scroll;
    }

    BeginScissorMode(rec.x, rec.y, rec.width, rec.height);
    for (int i = 1; i < lines; i++) {
        Vector2 pos = { .x = rec.x, .y = vertical_acc };
        char *line_start = text + spans[i-1];
        int line_length = spans[i] - spans[i-1];
        DrawTextEx(*font, 
                TextFormat("%.*s", line_length, line_start), 
                pos, height, SPACING_H, color);
        vertical_acc += height;
    }
    EndScissorMode();
}