#include "term.h"

#include <gint/display.h>
#include <gint/rtc.h>

#include <ctype.h>
#include <printf.h>
#include <stdarg.h>
#include <string.h>

extern font_t uf5x7;

struct tcell {
    char chr[4];
    int fg;
    int bg;
};

static struct tcell tgrid[UNS_TERM_ROWS][UNS_TERM_COLS];

static void tgrid_set(int row, int col, int fg, int bg, char c[4]) {
    tgrid[row][col].chr[0] = c[0];
    tgrid[row][col].chr[1] = c[1];
    tgrid[row][col].chr[2] = c[2];
    tgrid[row][col].chr[3] = c[3];
    tgrid[row][col].fg = fg;
    tgrid[row][col].bg = bg;
}

static int tgrid_sets(int *row, int *col, int fg, int bg, const char *s) {
    int i = 0;
    while (s[i] != '\0') {
        // boundary check
        if (*row >= UNS_TERM_ROWS)
            return i;
        if (*col >= UNS_TERM_COLS)
            return i;

        // detect utf-8 char length
        unsigned char lb = s[i];
        int charlen = 0;
        if ((lb & 0x80) == 0) // lead bit is zero, must be a single ascii
            charlen = 1;
        else if ((lb & 0xE0) == 0xC0) // 110x xxxx
            charlen = 2;
        else if ((lb & 0xF0) == 0xE0) // 1110 xxxx
            charlen = 3;
        else if ((lb & 0xF8) == 0xF0) // 1111 0xxx
            charlen = 4;

        char unichar[4];
        int j;
        for (j = 0; j < charlen; j++)
            unichar[j] = s[i + j];
        for (; j < 4; j++)
            unichar[j] = '\0';

        i += charlen;

        const int char_is_newline = (strncmp(unichar, "\n", 4) == 0);
        if (char_is_newline) {
            // clear line end
            for (; *col < UNS_TERM_COLS; *col = *col + 1)
                tgrid_set(*row, *col, C_WHITE, C_BLACK, " \0\0");
        } else {
            tgrid_set(*row, *col, fg, bg, unichar);
            *col = *col + 1;
        }
    }

    return i;
}

int term_writeat(int row, int col, int fg, int bg, const char *s) { return tgrid_sets(&row, &col, fg, bg, s); }

void tgrid_display(void) {
    dfont(&uf5x7);

    int y = 3;
    for (int row = 0; row < UNS_TERM_ROWS; row++) {
        int x = 2;
        for (int col = 0; col < UNS_TERM_COLS; col++) {
            const struct tcell cell = tgrid[row][col];

            // unpack unicode
            char buf[5];
            buf[0] = cell.chr[0];
            buf[1] = cell.chr[1];
            buf[2] = cell.chr[2];
            buf[3] = cell.chr[3];
            buf[4] = '\0';

            drect(x - 1, y - 1, x + 6, y + 8, cell.bg);
            dtext_opt(x, y, cell.fg, C_NONE, DTEXT_LEFT, DTEXT_TOP, (char *)&buf, -1);

            x += 1 + 5;
        }

        y += 1 + 7 + 2;
    }
}

void term_scroll_down(void) {
    // clear last line
    for (int i = 0; i < UNS_TERM_COLS; i++) {
        tgrid[UNS_TERM_ROWS - 1][i].chr[0] = ' ';
        tgrid[UNS_TERM_ROWS - 1][i].chr[1] = '\0';
        tgrid[UNS_TERM_ROWS - 1][i].chr[2] = '\0';
        tgrid[UNS_TERM_ROWS - 1][i].chr[3] = '\0';
        tgrid[UNS_TERM_ROWS - 1][i].fg = C_WHITE;
        tgrid[UNS_TERM_ROWS - 1][i].bg = C_BLACK;
    }

    for (int i = 1; i < UNS_TERM_ROWS - 1; i++) {
        memcpy(tgrid[i], tgrid[i + 1], UNS_TERM_COLS * sizeof(struct tcell));
    }
}

static int term_print_opt(const char *str, int fg, int bg) {
    static int row = 1;
    static int col = 0;

    int i = 0;

    while (str[i] != '\0') {
        // handle cursor overflow (column)
        if (col >= UNS_TERM_COLS) {
            col = 0;
            row++;
        }

        // handle cursor overflow (row)
        if (row >= UNS_TERM_ROWS - 1) {
            term_scroll_down();
            row = UNS_TERM_ROWS - 2;
        }

        i += tgrid_sets(&row, &col, fg, bg, str + i);
    }

    return i;
}

int term_print(const char *str) { return term_print_opt(str, C_WHITE, C_BLACK); }
int term_printf(const char *restrict format, ...) {
    va_list argp;
    va_start(argp, format);

    char buf[1024];
    const int n = vsnprintf(buf, sizeof(buf), format, argp);
    term_print(buf);

    va_end(argp);
    return n;
}

int term_eprint(const char *str) { return term_print_opt(str, C_RED, C_BLACK); }
int term_eprintf(const char *restrict format, ...) {
    va_list argp;
    va_start(argp, format);

    char buf[1024];
    const int n = vsnprintf(buf, sizeof(buf), format, argp);
    term_eprint(buf);

    va_end(argp);
    return n;
}

int term_kprint(const char *str) {
    int t = rtc_ticks();

    char kstr[256];
    sprintf(kstr, "[%5d:%03d] %s\n", t / 128, t % 128, str);

    const int ret = term_print_opt(kstr, C_RED | C_GREEN, C_BLACK);

    return ret;
}
int term_kprintf(const char *restrict format, ...) {
    va_list argp;
    va_start(argp, format);

    char buf[1024];
    const int n = vsnprintf(buf, sizeof(buf), format, argp);
    term_kprint(buf);

    va_end(argp);
    return n;
}