/*
 * Copyright (C) 2025 dwlr <dweller@cabin.digital>
 *
 * BSD 3-Clause License (BSD-3-Clause)
 * See LICENSE for details
 */


#define IUI_TXT_CENTER bit(0)
#define IUI_CLIP_CLEAR bit(0)

typedef struct
{
    enum
    {
        IUI_ILL,
        IUI_BOX,
        IUI_FILL,
        IUI_LINE,
        IUI_TEXT,
        IUI_CLIP,

    } type;

    u32 color;
    u16 x, y, w, h;
    u16 size;
    u16 flags;
    char* text;

} iui_cmd;

#define IUI_CMDBUF_LEN 512
typedef struct
{
    arena* ar;
    void* usr;

    usize hot;
    usize active;
    usize kbdfocus;

    /* mouse */
    u16 x;
    u16 y;

    u8 pbtns;
    u8 btns;

    /* TODO: event pump */

    usize ncmds;
    iui_cmd cmds[IUI_CMDBUF_LEN]; /* TODO: arena? */

} iui;


void iui_init(iui* ui, arena* ar, void* usr)
{
    if(!ui)
    {
        report(WARN, "iui: iui_init() ui == NULL!\n");
        return;
    }

    ui->ar  = ar;
    ui->usr = usr;
}

void iui_start(iui* ui)
{
    assert(ui);
    ui->hot = 0;

    ar_clear(ui->ar);
}

void iui_end(iui* ui)
{
    assert(ui);

    if(!ui->btns) ui->active = 0;
    else if(!ui->active) ui->kbdfocus = 0;

    ui->pbtns = ui->btns;
}

bool iui_mouse_inside(iui* ui, u16 x, u16 y, u16 w, u16 h)
{
    return !(ui->x < x || ui->y < y || ui->x >= x + w || ui->y >= y + h);
}

int iui_button(iui* ui, u16 x, u16 y, int w, int h, char* label)
{
    xctx*  x11 = (xctx*)ui->usr;
    usize   id = (usize)label;
    bool imhot, imactive;

    if(iui_mouse_inside(ui, x, y, w, h))
    {
        bool click = ui->btns & bit(1) && !(ui->pbtns & bit(1));
        if(!ui->active && click) ui->active = id;
        ui->hot = id;
    }

    imhot    = ui->hot    == id;
    imactive = ui->active == id;

    {
        iui_cmd cmd = {0};
        cmd.type = IUI_FILL;

        cmd.x = x;
        cmd.y = y;
        cmd.w = w;
        cmd.h = h;

        if(imhot) cmd.size = 2;
        else cmd.size = 1;

        if(imactive) cmd.color = x11->cols.as.fg;
        else cmd.color = x11->cols.as.bg;

        ui->cmds[ui->ncmds++] = cmd;

        cmd.type = IUI_BOX;
        cmd.color = x11->cols.as.fg;
        ui->cmds[ui->ncmds++] = cmd;

        cmd.type  = IUI_TEXT;
        cmd.size  = 14;
        cmd.text  = label;
        cmd.flags = IUI_TXT_CENTER;

        if(imactive) cmd.color = x11->cols.as.bg;
        else cmd.color = x11->cols.as.fg;

        ui->cmds[ui->ncmds++] = cmd;
    }

    return imhot && imactive && !(ui->btns & bit(1));
}

void iui_label(iui* ui, u16 x, u16 y, int w, int h, char* fmt, ...)
{
    int len = 0;
    char* buf = NULL;
    va_list ap = {0};
    xctx*  x11 = (xctx*)ui->usr;

    buf = ar_push(ui->ar, 512);

    va_start(ap, fmt);
        len = vsnprintf(buf, 511, fmt, ap);
    va_end(ap);

    {
        iui_cmd cmd = {0};
        cmd.type = IUI_FILL;

        cmd.x = x;
        cmd.y = y;
        cmd.w = w;
        cmd.h = h;

        {
            iui_cmd clip = cmd;
            clip.type = IUI_CLIP;
            clip.flags = 0;
            clip.x++;
            clip.y++;
            clip.w--;
            clip.h--;

            ui->cmds[ui->ncmds++] = clip;
        }

        {
            cmd.type  = IUI_TEXT;
            cmd.size  = 14;
            cmd.text  = buf;
            cmd.flags = 0;

            cmd.x = x + 6;
            cmd.y = y;
            cmd.w = w;
            cmd.h = h;

            cmd.color = x11->cols.as.fg;

            ui->cmds[ui->ncmds++] = cmd;
        }

        cmd.type  = IUI_CLIP;
        cmd.flags = IUI_CLIP_CLEAR;
        ui->cmds[ui->ncmds++] = cmd;
    }
}

int iui_editbox(iui* ui, u16 x, u16 y, int w, int h, char* buf, usize buflen)
{
    xctx*  x11 = (xctx*)ui->usr;
    usize   id = (usize)buf;
    bool imhot, imactive;
    usize len;

    len = strlen(buf);

    if(iui_mouse_inside(ui, x, y, w, h))
    {
        bool click = ui->btns & bit(1) && !(ui->pbtns & bit(1));
        if(!ui->active && click) ui->active = id;
        ui->hot = id;
    }

    imhot    = ui->hot    == id;
    imactive = ui->active == id;

    {
        iui_cmd cmd = {0};
        cmd.type = IUI_FILL;

        cmd.x = x;
        cmd.y = y;
        cmd.w = w;
        cmd.h = h;

        if(imhot) cmd.size = 2;
        else cmd.size = 1;

        cmd.color = x11->cols.as.bg;
        ui->cmds[ui->ncmds++] = cmd;

        cmd.type = IUI_BOX;
        cmd.color = x11->cols.as.fg;
        ui->cmds[ui->ncmds++] = cmd;

        {
            iui_cmd clip = cmd;
            clip.type = IUI_CLIP;
            clip.flags = 0;
            clip.x++;
            clip.y++;
            clip.w--;
            clip.h--;

            ui->cmds[ui->ncmds++] = clip;
        }

        if(imactive) ui->kbdfocus = id;
        if(ui->kbdfocus == id)
        {
            cmd.type = IUI_FILL;
            cmd.x = x + 6 + 6 * len;
            cmd.y = y + 6;
            cmd.w = 10;
            cmd.h = h - 12;
            cmd.color = x11->cols.as.fg;

            ui->cmds[ui->ncmds++] = cmd;
        }
        else
        {
            cmd.type = IUI_BOX;
            cmd.x = x + 6 + 6 * len;
            cmd.y = y + 6;
            cmd.w = 9;
            cmd.h = h - 13;
            cmd.color = x11->cols.as.fg;
            cmd.size = 1;

            ui->cmds[ui->ncmds++] = cmd;
        }

        {
            cmd.type  = IUI_TEXT;
            cmd.size  = 14;
            cmd.text  = buf;
            cmd.flags = 0;

            cmd.x = x + 6;
            cmd.y = y;
            cmd.w = w;
            cmd.h = h;

            cmd.color = x11->cols.as.fg;

            ui->cmds[ui->ncmds++] = cmd;
        }

        cmd.type  = IUI_CLIP;
        cmd.flags = IUI_CLIP_CLEAR;
        ui->cmds[ui->ncmds++] = cmd;
    }

    return imhot && imactive && !(ui->btns & bit(1));
}


void iui_draw(iui* ui);