#include "editor.h"
#include <SDL2/SDL_render.h>
#include <SDL2/SDL_ttf.h>

void render_text(
    SDL_Renderer* renderer, const char* text, TTF_Font* font, int x, int y,
    SDL_Color fg, SDL_Color bg);

void editor_init(
    Editor* editor, int width, int height, AppRessources* ressources)
{
    *editor = (Editor) {
        .buffer = nullptr,
        width,
        height,
        .cursor_idx = 0,
        .cursor_line = 1,
        .cursor_col = 1,
        ressources,
    };
}

void editor_open(Editor* editor, Buffer* buffer)
{
    editor->buffer = buffer;
    editor->cursor_idx = 0;
    editor->cursor_line = 1;
    editor->cursor_col = 1;
}

static int cols_at_idx(Editor* editor, size_t idx)
{
    Buffer* buffer = editor->buffer;

    int line_start = (int)idx;
    while (line_start > 0 && buffer->text[line_start] != '\n') {
        line_start -= 1;
    }
    int line_end = (int)idx + 1;
    while (line_end < (int)buffer->text_length
           && buffer->text[line_end] != '\n') {
        line_end += 1;
    }
    printf("idx = %ld, cols = %d\n", idx, line_end - line_start);
    return line_end - line_start;
}

static void cursor_increment(Editor* editor)
{
    if (editor->cursor_idx >= editor->buffer->text_length)
        return;
    if (editor->buffer->text[editor->cursor_idx] == '\n') {
        editor->cursor_line += 1;
        editor->cursor_col = 1;
    } else {
        editor->cursor_col += 1;
    }
    editor->cursor_idx += 1;
}

static void cursor_decrement(Editor* editor)
{
    if (editor->cursor_idx <= 0)
        return;
    editor->cursor_idx -= 1;
    if (editor->buffer->text[editor->cursor_idx] == '\n') {
        editor->cursor_line -= 1;
        editor->cursor_col = cols_at_idx(editor, editor->cursor_idx);
    } else {
        editor->cursor_col -= 1;
    }
}

void editor_cursor_up(Editor* editor)
{
    if (editor->cursor_line == 1)
        return;
    int originalLine = editor->cursor_line;
    int originalCol = editor->cursor_col;
    while (editor->cursor_line >= originalLine
           || editor->cursor_col > originalCol) {
        cursor_decrement(editor);
    }
}

void editor_cursor_down(Editor* editor)
{
    int originalLine = editor->cursor_line;
    int originalCol = editor->cursor_col;
    while (editor->cursor_line <= originalLine
           || editor->cursor_col > originalCol) {
        cursor_increment(editor);
    }
}

void editor_cursor_left(Editor* editor)
{
}

void editor_cursor_right(Editor* editor)
{
}

void editor_render(Editor* editor, void* renderer, int x, int y)
{
    Theme* theme = &editor->ressources->theme;
    SDL_Color fg = *(SDL_Color*)&theme->foreground;
    SDL_Color bg = *(SDL_Color*)&theme->background;

    SDL_SetRenderDrawColor(renderer, bg.r, bg.g, bg.b, bg.a);
    SDL_RenderFillRect(
        renderer, &(SDL_Rect) { 0, 0, editor->width, editor->height });

    TextSize char_size = editor->ressources->char_size;

    Buffer* buffer = editor->buffer;

    size_t i = 0;
    int line = 1;
    int offset_y = 0;

    while (i < buffer->text_length) {
        size_t line_start = i;
        while (i < buffer->text_length && buffer->text[i] != '\n') {
            i += 1;
        }

        char line_number[16] = "";
        snprintf(line_number, 15, "%4d", line);

        TextSize ln_size = text_size(line_number, editor->ressources->font);
        render_text(
            renderer,
            line_number,
            editor->ressources->font,
            x,
            y + offset_y,
            *(SDL_Color*)&theme->linenumber,
            bg);

        char* line_text = strndup(&buffer->text[line_start], i - line_start);
        TextSize line_size = text_size(line_text, editor->ressources->font);
        render_text(
            renderer,
            line_text,
            editor->ressources->font,
            x + ln_size.width + 8,
            y + offset_y,
            fg,
            bg);
        free(line_text);

        offset_y += line_size.height;

        if (i < buffer->text_length && buffer->text[i] == '\n') {
            i += 1;
        }
        line += 1;
    }

    SDL_SetRenderDrawColor(renderer, fg.r, fg.g, fg.b, fg.a);
    SDL_RenderFillRect(
        renderer,
        &(SDL_Rect) {
            x + char_size.width * (editor->cursor_col - 1 + 4) + 8 - 1,
            y + char_size.height * (editor->cursor_line - 1),
            2,
            char_size.height,
        });
}