#include "term.h"

#include <signal.h>
#include <sys/ioctl.h>

struct ExtraInfo
{
    char *enteralt;
    char *exitalt;

    char *entermouse;
    char *exitmouse;
};

static 
struct ExtraInfo vt200 =
{
    .enteralt = "\e[?1049h",
    .exitalt  = "\e[?1049l",

    .entermouse = "\e[?1049h\e[?1006l",
    .exitmouse  = "\e[?1002l\e[?1006l",
};

static Term *sigwinchhead; 

// -----------------------------------------------------------------------
// database lookup

static
char*
tryinfostr(Term *t, enum unibi_string s)
{
    char *val = (char*)unibi_get_str(t->info, s);
    /* TODO: provide fallbacks */
    return val;
}

static
char*
guessinfostr(Term *t, enum unibi_string s, char *guess)
{
    char *val = (char*)unibi_get_str(t->info, s);
    if (!val)
        return guess;
    return val;
}

static
char*
getinfostr(Term *t, enum unibi_string s)
{
    char *val = tryinfostr(t, s);
    if (!val)
        panicf("required term info string '%s' missing", unibi_name_str(s));

    return val;
}

static
char *
tryextrastr(Term *t, char *name)
{
    const char *nm;
    size_t max = unibi_count_ext_str(t->info);
    for (size_t i = 0; i < max; i++) {
        nm = unibi_get_ext_str_name(t->info, i);
        if (nm && !strcmp(nm, name)) {
            return (char *)nm;
        }
    }
    return nil;
}

static
char *
guessextrastr(Term *t, char *name, char *guess)
{
    char *s;
    if ((s = tryextrastr(t, name)))
        return s;

    return guess;
}

/* formats escape strings and writes to output */
static void tfmt(Term *t, char *esc, int n, ...);
static void tclear(Term *t);

// -----------------------------------------------------------------------
// exported term methods

static
char *
ttmpbuf(Term *t, int len)
{
    if (t->tmp.len >= len)
        return t->tmp.b;

    /* TODO: error handling */
    return (t->tmp.b = realloc(t->tmp.b, len));
}

void twrite(Term *t, long len, char *s);
void tlistensigwinch(Term *t);

Term*
tmake(void)
{
    Term *t;

    t = calloc(1, sizeof(*t));

    /* meta data */
    t->name = getenv("TERM");
    t->info = unibi_from_term(t->name);
    if (!t->info)
        panicf("could not identify terminal");

    t->fd = 1; // stdout
    tlistensigwinch(t);

    t->mode.mouse     = 0;
    t->mode.cursorvis = 1;
    t->mode.altscreen = 0;

    t->cap.colors = unibi_get_num(t->info, unibi_max_colors);
    t->cap.bce    = unibi_get_bool(t->info, unibi_back_color_erase);

    /* initialize root window (get current size)*/
    struct winsize ws = { 0 };
    if (ioctl(t->fd, TIOCGWINSZ, &ws) == 1)
        goto bad;

    t->root = wmake(nil, 0, 0, ws.ws_col, ws.ws_row, 0);

    t->root->curvis = 1;
    t->root->blink  = 0;

    t->pen = (Pen){
        .state = PenNormal,
        .col   = {.fg = -1, .bg = -1},
    };

    /* fill in output buffers */
    t->buf.c   = t->buf.b;
    t->tmp.b   = nil;
    t->tmp.len = 0;

    /* get all term info format strings */
    t->esc.cup    = getinfostr(t, unibi_cursor_address);
    t->esc.vpa    = tryinfostr(t, unibi_row_address);
    t->esc.hpa    = tryinfostr(t, unibi_column_address);
    t->esc.cuu    = getinfostr(t, unibi_parm_up_cursor);
    t->esc.cuu1   = tryinfostr(t, unibi_cursor_up);
    t->esc.cud    = getinfostr(t, unibi_parm_down_cursor);
    t->esc.cud1   = tryinfostr(t, unibi_cursor_down);
    t->esc.cuf    = getinfostr(t, unibi_parm_right_cursor);
    t->esc.cuf1   = tryinfostr(t, unibi_cursor_right);
    t->esc.cub    = getinfostr(t, unibi_parm_left_cursor);
    t->esc.cub1   = tryinfostr(t, unibi_cursor_left);
    t->esc.ich    = getinfostr(t, unibi_parm_ich);
    t->esc.ich1   = tryinfostr(t, unibi_insert_character);
    t->esc.dch    = getinfostr(t, unibi_parm_dch);
    t->esc.dch1   = tryinfostr(t, unibi_delete_character);
    t->esc.il     = getinfostr(t, unibi_parm_insert_line);
    t->esc.il1    = tryinfostr(t, unibi_insert_line);
    t->esc.dl     = getinfostr(t, unibi_parm_delete_line);
    t->esc.dl1    = tryinfostr(t, unibi_delete_line);
    t->esc.ech    = getinfostr(t, unibi_erase_chars);
    t->esc.ed2    = getinfostr(t, unibi_clear_screen);
    t->esc.stbm   = getinfostr(t, unibi_change_scroll_region);
    t->esc.sgr    = getinfostr(t, unibi_set_attributes);
    t->esc.sgr0   = getinfostr(t, unibi_exit_attribute_mode);
    t->esc.sgr_i0 = tryinfostr(t, unibi_exit_italics_mode);
    t->esc.sgr_i1 = tryinfostr(t, unibi_enter_italics_mode);
    t->esc.sgr_fg = getinfostr(t, unibi_set_a_foreground);
    t->esc.sgr_bg = getinfostr(t, unibi_set_a_background);
    t->esc.sm_csr = getinfostr(t, unibi_cursor_normal);
    t->esc.rm_csr = getinfostr(t, unibi_cursor_invisible);

    /* extensions to terminfo */
    t->esc.ext.rgbf = guessextrastr(t, "setrgbf", "\x1b[38;2;%p1%d;%p2%d;%p3%dm");
    t->esc.ext.rgbb = guessextrastr(t, "setrgbb", "\x1b[48;2;%p1%d;%p2%d;%p3%dm");

    return t;

bad:
    panicf("failed to initialize terminal instance");
    free(t);
    return nil;
}

void
tfree(Term *t)
{
    if (t->mode.mouse)
        twrite(t, 0, vt200.exitmouse);
    if (!t->mode.cursorvis)
        tfmt(t, t->esc.rm_csr, 0);
    if (t->mode.altscreen)
        twrite(t, 0, vt200.exitalt);

    tfmt(t, t->esc.sgr0, 0);
    tclear(t);
    free(t);
}

/* handle resize events */
void
tresize(Term *t)
{
    if (t->fd == -1)
        return;

    struct winsize ws = { 0 };
    if (ioctl(t->fd, TIOCGWINSZ, &ws) == 1)
        return;

    printf("[%d,%d]\n", ws.ws_col, ws.ws_row);
    if (t->root->w != ws.ws_col || t->root->h != ws.ws_row)
        wresize(t->root, ws.ws_col, ws.ws_row);
}

static
void
sigwinch(int num)
{
    Term *it;
    for (it = sigwinchhead; it; it = it->link)
        tresize(it);
}

void
tlistensigwinch(Term *t)
{
    sigset_t new, old;
    Term *it;

    sigemptyset(&new);
    sigaddset(&new, SIGWINCH);
    sigprocmask(SIG_BLOCK, &new, &old);

    if (!sigwinchhead) {
        sigaction(SIGWINCH, &(struct sigaction){ .sa_handler = sigwinch }, nil);
        sigwinchhead = t;
    } else {
        it = sigwinchhead;
        while (it->link)
            it = it->link;
        it->link = t;
    }

    sigprocmask(SIG_SETMASK, &old, nil);
}

void
tflush(Term *t)
{
    if (t->fd != -1)
        write(t->fd, t->buf.b, t->buf.c - t->buf.b);

    t->buf.c = t->buf.b;
}

void
twrite(Term *t, long len, char *s)
{
    int n;
    if (!len)
        len = strlen(s);

loop:
    n = MIN(len, arrend(t->buf.b) - t->buf.c);
    memcpy(t->buf.c, s, n);
    t->buf.c += n;
    len      -= n;
    if (len) {
        tflush(t);
        goto loop;
    }
}

void
tsetpen(Term *t, Pen new)
{
    int c;
    ushort ic, in;
    Pen cur = t->pen;
    if (!memcmp(&new, &cur, sizeof(new)))
        return;

    /* attributes */
    tfmt(t, t->esc.sgr, 9,
        0, /* standout */
        new.state & PenUnderline,
        new.state & PenReverse,
        new.state & PenBlink,
        new.state & PenDim,
        new.state & PenBold,
        new.state & PenInvis,
        0,   /* protect */
        0);  /* alt     */

    ic = cur.state & PenItalic;
    in = new.state & PenItalic;
    if (ic & ~in)
        tfmt(t, t->esc.sgr_i0, 0);
    else if (~ic & in)
        tfmt(t, t->esc.sgr_i1, 0);

    /* fg/bg color */
    /* TODO: add a check for if the terminal supports true color */
    /* TODO: deal w/ negative indices properly */
    if (new.state & PenRGB) {
        tfmt(t, t->esc.ext.rgbf, 3, new.rgb.fg.r, new.rgb.fg.g, new.rgb.fg.b);
        tfmt(t, t->esc.ext.rgbb, 3, new.rgb.bg.r, new.rgb.bg.g, new.rgb.bg.b);
    } else {
        tfmt(t, t->esc.sgr_fg, 1, new.col.fg);
        tfmt(t, t->esc.sgr_bg, 1, new.col.bg);
    }

    t->pen = new;
}

static
void
tfmt(Term *t, char *esc, int n, ...)
{
    int  i;
    long len;
    va_list args;
    unibi_var_t param[9];
    char buf[64], *c = buf;

    if (!esc)
        panicf("no terminfo escape string given");

    va_start(args, n);
    for (i = 0; i < arrlen(param) && i < n; i++) {
        param[i] = unibi_var_from_num(va_arg(args, int));
    }
    va_end(args);

    len = unibi_run(esc, param, c, sizeof(buf));
    if (len >= arrlen(buf)) {
        c = ttmpbuf(t, len);
        unibi_run(esc, param, c, len);
    }

    twrite(t, len, c);
}

/* absolute move */
static
int
tgoto(Term *t, int row, int col)
{
    if (row != -1 && col != -1)
        tfmt(t, t->esc.cup, 2, row, col);
    else if (row != -1) {
        if (!t->esc.vpa)
            return 0;
        tfmt(t, t->esc.vpa, 1, row);
    } else if (col != -1) {
        if (col == 0) {
            twrite(t, 1, "\r");
            return 1;
        }
        if (t->esc.hpa)
            tfmt(t, t->esc.hpa, 1, col);
        else if (t->esc.cuf) {
            twrite(t, 1, "\r");
            tfmt(t, t->esc.cuf, 1, col);
        } else
            return 0;
    } else
        return 0; /* unreachable */

    return 1;
}

/* relative move */
static
void
tjump(Term *t, int down, int right)
{
  if (down == 1 && t->esc.cud1)
    tfmt(t, t->esc.cud1, 0);
  else if (down == -1 && t->esc.cuu1)
    tfmt(t, t->esc.cuu1, 0);
  else if (down > 0)
    tfmt(t, t->esc.cud, 1, down);
  else if (down < 0)
    tfmt(t, t->esc.cuu, 1, -down);

  if (right == 1 && t->esc.cuf1)
    tfmt(t, t->esc.cuf1, 0);
  else if (right == -1 && t->esc.cub1)
    tfmt (t, t->esc.cub1, 0);
  else if (right > 0)
    tfmt(t, t->esc.cuf, 1, right);
  else if( right < 0)
    tfmt(t, t->esc.cub, 1, -right);
}

static
void
tclear(Term *t)
{
    tfmt(t, t->esc.ed2, 0);
}

void
tblit(Term *t, Window *win)
{
    int r, c, n, j;
    Row *row;
    char u[UTFmax+1] = {0};

    j = 0;
    tgoto(t, win->top, win->left);
    for (r = 0; r < win->h; r++) {
        row = win->row + r;
        if (!row->dirty) {
            j++;
            continue;
        }

        if (j) {
            tjump(t, j, 0);
            j = 0;
        }

        for (c = 0; c < win->w; c++) {
            tsetpen(t, row->cells[c].pen);
            n = utf8·runetobyte(u, &row->cells[c].txt);
            twrite(t, n, u);
        }

        row->dirty = 0;
    }

    tflush(t);
}

// -----------------------------------------------------------------------
// testing

int
main()
{
    int i;
    Term   *t;
    Window *win;

    t   = tmake();
    win = t->root;
    tclear(t);

    win->pen = (Pen){
        .state = PenNormal,
        .col   = {.fg=-1, .bg=-1},
    };
    for (i = 0; i < 2000; i++)
        wputrune(win, 'a');

    tblit(t, win);

    win->cur.row = 10;
    win->cur.col = 0;

    win->pen = (Pen){
        .state=PenNormal|PenRGB,
        .rgb={.fg={200, 100, 100}, .bg={0, 0, 0} },
    };

    for (i = 0; i < 500; i++)
        wputrune(win, 'b');

    tblit(t, win);

    sleep(5);
    wscroll(win, 10);
    tblit(t, win);
    sleep(5);

    tfree(t);
}