From 42b780fd3aeb8ad6541de05eacb4e7202ccfca5e Mon Sep 17 00:00:00 2001
From: Zach Potter <zspotting@gmail.com>
Date: Sun, 20 Aug 2023 23:26:55 -0700
Subject: Rework keyboard and implement global terminal

---
 virtual-programs/terminal.folk | 170 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 170 insertions(+)
 create mode 100644 virtual-programs/terminal.folk

(limited to 'virtual-programs')

diff --git a/virtual-programs/terminal.folk b/virtual-programs/terminal.folk
new file mode 100644
index 00000000..df333d28
--- /dev/null
+++ b/virtual-programs/terminal.folk
@@ -0,0 +1,170 @@
+# Terminal
+#
+# Claim $this is a terminal
+#
+
+set cc [c create]
+$cc cflags -I./vendor/libtmt ./vendor/libtmt/tmt.c
+
+# TODO: find the right libutil.so for the system
+c loadlib /lib/aarch64-linux-gnu/libutil.so
+$cc cflags -lutil
+
+$cc include <sys/types.h>
+$cc include <stdio.h>
+$cc include <stdlib.h>
+$cc include <unistd.h>
+$cc include <pty.h>
+$cc include <fcntl.h>
+$cc include <string.h>
+$cc include <sys/time.h> ;# For gettimeofday()
+
+$cc code {
+  #include "tmt.h"
+
+  #define SHELL "/bin/bash"
+
+  #define ROWS 12
+  #define COLS 43
+  char screen[ROWS][COLS + 1];
+  int curs_r = 0;
+  int curs_c = 0;
+
+
+  #define PTYBUF 4096
+  char iobuf[PTYBUF];
+
+  TMT *vt;
+  int pty_fd;
+
+  void callback(tmt_msg_t m, TMT *vt, const void *a, void *p) {
+      const TMTSCREEN *s = tmt_screen(vt);
+
+      if (m == TMT_MSG_UPDATE) {
+        for (size_t r = 0; r < s->nline; r++){
+            if (s->lines[r]->dirty){
+                for (size_t c = 0; c < s->ncol; c++){
+                  screen[r][c] = s->lines[r]->chars[c].c;
+                }
+            }
+        }
+        tmt_clean(vt);
+      }
+  }
+
+  void initScreen() {
+    for (int r = 0; r < ROWS - 1; r++) {
+      screen[r][COLS] = '\n';
+    }
+    screen[ROWS - 1][COLS] = '\0';
+  }
+
+  void updateCursor() {
+    // Restore char under old cursor
+    const TMTSCREEN *s = tmt_screen(vt);
+    screen[curs_r][curs_c] = s->lines[curs_r]->chars[curs_c].c;
+
+    // Update new cursor
+    const TMTPOINT *c = tmt_cursor(vt);
+    curs_r = c->r;
+    curs_c = c->c;
+
+    // Replace char with cursor every other second
+    struct timeval tv;
+    gettimeofday(&tv, NULL);
+    if (tv.tv_sec % 2 == 0) {
+      screen[curs_r][curs_c] = 0xDB; // block char: █
+    }
+  }
+}
+
+$cc proc termInit {} bool {
+  if (vt != NULL) {
+    return false;
+  }
+
+  initScreen();
+  vt = tmt_open(ROWS, COLS, callback, NULL, NULL);
+
+  struct winsize ws = {.ws_row = ROWS, .ws_col = COLS};
+  pid_t pid = forkpty(&pty_fd, NULL, NULL, &ws);
+  if (pid < 0){
+    return false;
+  } else if (pid == 0){
+    setenv("TERM", "ansi", 1);
+    execl(SHELL, SHELL, NULL);
+    return true;
+  }
+
+  fcntl(pty_fd, F_SETFL, O_NONBLOCK);
+  return true;
+}
+
+$cc proc termRead {} char* {
+  ssize_t r = read(pty_fd, iobuf, PTYBUF);
+  if (r > 0) {
+    tmt_write(vt, iobuf, r);
+  }
+
+  updateCursor();
+  return (char*)screen;
+}
+
+$cc proc termWrite {char* key} void {
+  write(pty_fd, key, strlen(key));
+}
+
+$cc compile
+
+# Folk stuff...
+
+# From `man console_codes`
+set keymap [dict create \
+  ENTER     "\x0d" \
+  TAB       "\x09" \
+  BACKSPACE "\x08" \
+  DELETE    "\x7f" \
+  ESC       "\x1b" \
+  UP        "\x1b\[A" \
+  DOWN      "\x1b\[B" \
+  RIGHT     "\x1b\[C" \
+  LEFT      "\x1b\[D" \
+]
+
+proc remap {key modifiers} {
+  upvar keymap keymap
+  if {[string length $key] == 1} {
+    # Convert ctrl-A through ctrl-Z and others to terminal control characters
+    if {"ctrl" in $modifiers} {
+      set charCode [scan [string toupper $key] %c]
+      if {$charCode >= 64 && $charCode <= 95} {
+        set charCode [expr {$charCode - 64}]
+        return [format %c $charCode]
+      }
+    }
+    # All other single char keys can be passed through
+    return $key
+  }
+  if {[dict exists $keymap $key]} {
+    return [dict get $keymap $key]
+  }
+  return ""
+}
+
+When /anyone/ claims /thing/ is a terminal {
+  termInit
+
+  When /anyone/ claims key /key/ is /direction/ with modifiers /modifiers/ {
+    if {$direction != "up"} {
+      set key [remap $key $modifiers]
+      if {[string length $key] > 0} {
+        termWrite $key
+      }
+    }
+  }
+
+  When $thing has region /r/ & /node/ has step count /c/ {
+    set display [region move $r up 180px]
+    Wish region $display is labelled [termRead]
+  }
+}
-- 
cgit v1.2.3