# font8x8_basic (printable ASCII 0x20..0x7f), one row of 8 glyphs per line
# each glyph is 8 bytes; bit 0 (LSB) of a byte is the leftmost pixel
global FONT = {
  { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
  { 0x18, 0x3C, 0x3C, 0x18, 0x18, 0x00, 0x18, 0x00 },
  { 0x36, 0x36, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
  { 0x36, 0x36, 0x7F, 0x36, 0x7F, 0x36, 0x36, 0x00 },
  { 0x0C, 0x3E, 0x03, 0x1E, 0x30, 0x1F, 0x0C, 0x00 },
  { 0x00, 0x63, 0x33, 0x18, 0x0C, 0x66, 0x63, 0x00 },
  { 0x1C, 0x36, 0x1C, 0x6E, 0x3B, 0x33, 0x6E, 0x00 },
  { 0x06, 0x06, 0x03, 0x00, 0x00, 0x00, 0x00, 0x00 },
  { 0x18, 0x0C, 0x06, 0x06, 0x06, 0x0C, 0x18, 0x00 },
  { 0x06, 0x0C, 0x18, 0x18, 0x18, 0x0C, 0x06, 0x00 },
  { 0x00, 0x66, 0x3C, 0xFF, 0x3C, 0x66, 0x00, 0x00 },
  { 0x00, 0x0C, 0x0C, 0x3F, 0x0C, 0x0C, 0x00, 0x00 },
  { 0x00, 0x00, 0x00, 0x00, 0x00, 0x0C, 0x0C, 0x06 },
  { 0x00, 0x00, 0x00, 0x3F, 0x00, 0x00, 0x00, 0x00 },
  { 0x00, 0x00, 0x00, 0x00, 0x00, 0x0C, 0x0C, 0x00 },
  { 0x60, 0x30, 0x18, 0x0C, 0x06, 0x03, 0x01, 0x00 },
  { 0x3E, 0x63, 0x73, 0x7B, 0x6F, 0x67, 0x3E, 0x00 },
  { 0x0C, 0x0E, 0x0C, 0x0C, 0x0C, 0x0C, 0x3F, 0x00 },
  { 0x1E, 0x33, 0x30, 0x1C, 0x06, 0x33, 0x3F, 0x00 },
  { 0x1E, 0x33, 0x30, 0x1C, 0x30, 0x33, 0x1E, 0x00 },
  { 0x38, 0x3C, 0x36, 0x33, 0x7F, 0x30, 0x78, 0x00 },
  { 0x3F, 0x03, 0x1F, 0x30, 0x30, 0x33, 0x1E, 0x00 },
  { 0x1C, 0x06, 0x03, 0x1F, 0x33, 0x33, 0x1E, 0x00 },
  { 0x3F, 0x33, 0x30, 0x18, 0x0C, 0x0C, 0x0C, 0x00 },
  { 0x1E, 0x33, 0x33, 0x1E, 0x33, 0x33, 0x1E, 0x00 },
  { 0x1E, 0x33, 0x33, 0x3E, 0x30, 0x18, 0x0E, 0x00 },
  { 0x00, 0x0C, 0x0C, 0x00, 0x00, 0x0C, 0x0C, 0x00 },
  { 0x00, 0x0C, 0x0C, 0x00, 0x00, 0x0C, 0x0C, 0x06 },
  { 0x18, 0x0C, 0x06, 0x03, 0x06, 0x0C, 0x18, 0x00 },
  { 0x00, 0x00, 0x3F, 0x00, 0x00, 0x3F, 0x00, 0x00 },
  { 0x06, 0x0C, 0x18, 0x30, 0x18, 0x0C, 0x06, 0x00 },
  { 0x1E, 0x33, 0x30, 0x18, 0x0C, 0x00, 0x0C, 0x00 },
  { 0x3E, 0x63, 0x7B, 0x7B, 0x7B, 0x03, 0x1E, 0x00 },
  { 0x0C, 0x1E, 0x33, 0x33, 0x3F, 0x33, 0x33, 0x00 },
  { 0x3F, 0x66, 0x66, 0x3E, 0x66, 0x66, 0x3F, 0x00 },
  { 0x3C, 0x66, 0x03, 0x03, 0x03, 0x66, 0x3C, 0x00 },
  { 0x1F, 0x36, 0x66, 0x66, 0x66, 0x36, 0x1F, 0x00 },
  { 0x7F, 0x46, 0x16, 0x1E, 0x16, 0x46, 0x7F, 0x00 },
  { 0x7F, 0x46, 0x16, 0x1E, 0x16, 0x06, 0x0F, 0x00 },
  { 0x3C, 0x66, 0x03, 0x03, 0x73, 0x66, 0x7C, 0x00 },
  { 0x33, 0x33, 0x33, 0x3F, 0x33, 0x33, 0x33, 0x00 },
  { 0x1E, 0x0C, 0x0C, 0x0C, 0x0C, 0x0C, 0x1E, 0x00 },
  { 0x78, 0x30, 0x30, 0x30, 0x33, 0x33, 0x1E, 0x00 },
  { 0x67, 0x66, 0x36, 0x1E, 0x36, 0x66, 0x67, 0x00 },
  { 0x0F, 0x06, 0x06, 0x06, 0x46, 0x66, 0x7F, 0x00 },
  { 0x63, 0x77, 0x7F, 0x7F, 0x6B, 0x63, 0x63, 0x00 },
  { 0x63, 0x67, 0x6F, 0x7B, 0x73, 0x63, 0x63, 0x00 },
  { 0x1C, 0x36, 0x63, 0x63, 0x63, 0x36, 0x1C, 0x00 },
  { 0x3F, 0x66, 0x66, 0x3E, 0x06, 0x06, 0x0F, 0x00 },
  { 0x1E, 0x33, 0x33, 0x33, 0x3B, 0x1E, 0x38, 0x00 },
  { 0x3F, 0x66, 0x66, 0x3E, 0x36, 0x66, 0x67, 0x00 },
  { 0x1E, 0x33, 0x07, 0x0E, 0x38, 0x33, 0x1E, 0x00 },
  { 0x3F, 0x2D, 0x0C, 0x0C, 0x0C, 0x0C, 0x1E, 0x00 },
  { 0x33, 0x33, 0x33, 0x33, 0x33, 0x33, 0x3F, 0x00 },
  { 0x33, 0x33, 0x33, 0x33, 0x33, 0x1E, 0x0C, 0x00 },
  { 0x63, 0x63, 0x63, 0x6B, 0x7F, 0x77, 0x63, 0x00 },
  { 0x63, 0x63, 0x36, 0x1C, 0x1C, 0x36, 0x63, 0x00 },
  { 0x33, 0x33, 0x33, 0x1E, 0x0C, 0x0C, 0x1E, 0x00 },
  { 0x7F, 0x63, 0x31, 0x18, 0x4C, 0x66, 0x7F, 0x00 },
  { 0x1E, 0x06, 0x06, 0x06, 0x06, 0x06, 0x1E, 0x00 },
  { 0x03, 0x06, 0x0C, 0x18, 0x30, 0x60, 0x40, 0x00 },
  { 0x1E, 0x18, 0x18, 0x18, 0x18, 0x18, 0x1E, 0x00 },
  { 0x08, 0x1C, 0x36, 0x63, 0x00, 0x00, 0x00, 0x00 },
  { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xFF },
  { 0x0C, 0x0C, 0x18, 0x00, 0x00, 0x00, 0x00, 0x00 },
  { 0x00, 0x00, 0x1E, 0x30, 0x3E, 0x33, 0x6E, 0x00 },
  { 0x07, 0x06, 0x06, 0x3E, 0x66, 0x66, 0x3B, 0x00 },
  { 0x00, 0x00, 0x1E, 0x33, 0x03, 0x33, 0x1E, 0x00 },
  { 0x38, 0x30, 0x30, 0x3E, 0x33, 0x33, 0x6E, 0x00 },
  { 0x00, 0x00, 0x1E, 0x33, 0x3F, 0x03, 0x1E, 0x00 },
  { 0x1C, 0x36, 0x06, 0x0F, 0x06, 0x06, 0x0F, 0x00 },
  { 0x00, 0x00, 0x6E, 0x33, 0x33, 0x3E, 0x30, 0x1F },
  { 0x07, 0x06, 0x36, 0x6E, 0x66, 0x66, 0x67, 0x00 },
  { 0x0C, 0x00, 0x0E, 0x0C, 0x0C, 0x0C, 0x1E, 0x00 },
  { 0x30, 0x00, 0x30, 0x30, 0x30, 0x33, 0x33, 0x1E },
  { 0x07, 0x06, 0x66, 0x36, 0x1E, 0x36, 0x67, 0x00 },
  { 0x0E, 0x0C, 0x0C, 0x0C, 0x0C, 0x0C, 0x1E, 0x00 },
  { 0x00, 0x00, 0x33, 0x7F, 0x7F, 0x6B, 0x63, 0x00 },
  { 0x00, 0x00, 0x1F, 0x33, 0x33, 0x33, 0x33, 0x00 },
  { 0x00, 0x00, 0x1E, 0x33, 0x33, 0x33, 0x1E, 0x00 },
  { 0x00, 0x00, 0x3B, 0x66, 0x66, 0x3E, 0x06, 0x0F },
  { 0x00, 0x00, 0x6E, 0x33, 0x33, 0x3E, 0x30, 0x78 },
  { 0x00, 0x00, 0x3B, 0x6E, 0x66, 0x06, 0x0F, 0x00 },
  { 0x00, 0x00, 0x3E, 0x03, 0x1E, 0x30, 0x1F, 0x00 },
  { 0x08, 0x0C, 0x3E, 0x0C, 0x0C, 0x2C, 0x18, 0x00 },
  { 0x00, 0x00, 0x33, 0x33, 0x33, 0x33, 0x6E, 0x00 },
  { 0x00, 0x00, 0x33, 0x33, 0x33, 0x1E, 0x0C, 0x00 },
  { 0x00, 0x00, 0x63, 0x6B, 0x7F, 0x7F, 0x36, 0x00 },
  { 0x00, 0x00, 0x63, 0x36, 0x1C, 0x36, 0x63, 0x00 },
  { 0x00, 0x00, 0x33, 0x33, 0x33, 0x3E, 0x30, 0x1F },
  { 0x00, 0x00, 0x3F, 0x19, 0x0C, 0x26, 0x3F, 0x00 },
  { 0x38, 0x0C, 0x0C, 0x07, 0x0C, 0x0C, 0x38, 0x00 },
  { 0x18, 0x18, 0x18, 0x00, 0x18, 0x18, 0x18, 0x00 },
  { 0x07, 0x0C, 0x0C, 0x38, 0x0C, 0x0C, 0x07, 0x00 },
  { 0x6E, 0x3B, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
  { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
}

const SCALE = 2
const CW = 8 * SCALE
const CH = 8 * SCALE
const FG = 0xd0d0d0
const CON_BG = 0x101018
global con = { col = 0, row = 0 }

fn con_cols() fb_width() / CW
fn con_rows() fb_height() / CH

fn draw_glyph(col, row, ch) do
  const x0 = col * CW
  const y0 = row * CH
  fill_rect(x0, y0, CW, CH, CON_BG) # clear the cell
  const code = ch:ascii()
  if code < 32 return :nil
  if code > 127 return :nil
  const g = FONT[code - 32]
  for fy in 0..8 do
    const bits = g[fy]
    for fx in 0..8 do
      if (bits shr fx) band 1 == 1 fill_rect(x0 + fx * SCALE, y0 + fy * SCALE, SCALE, SCALE, FG)
    end
  end
end

fn con_newline() do
  con.col = 0
  con.row = con.row + 1
  if con.row >= con_rows() do
    fb_scroll(CH, CON_BG)
    con.row = con_rows() - 1
  end
end

# we dont do Shift/Cntrl
# thats a job for future me lmao
fn con_putc(ch) do
  const code = ch:ascii()
  if code == 10 do con_newline() return :nil end # \n
  if code == 13 do con.col = 0 return :nil end   # \r
  if code == 8 do                                # backspace: move left
    if con.col > 0 con.col = con.col - 1
    return :nil
  end
  if code < 32 return :nil
  draw_glyph(con.col, con.row, ch)
  con.col = con.col + 1
  if con.col >= con_cols() con_newline()
end

# render a string to the screen and mirror to serial
fn puts(s) do
  serial_puts(s)
  for i in 0..s:len() do con_putc(s[i]) end
end

# keyboard scancode table
# ts is NOT a good way to write a driver LMAO
const KBD = "  1234567890-=  qwertyuiop[]  asdfghjkl;'` \\zxcvbnm,./    "

# 8259 PIC
fn pic_remap() do
  outb(0x20, 0x11)  outb(0xa0, 0x11)
  outb(0x21, 0x20)  outb(0xa1, 0x28)
  outb(0x21, 0x04)  outb(0xa1, 0x02)
  outb(0x21, 0x01)  outb(0xa1, 0x01)
  outb(0x21, 0xff)  outb(0xa1, 0xff)
end
fn pic_unmask(line) outb(0x21, inb(0x21) band (255 bxor (1 shl line)))

# this is just a simple prompt to test that shit is working
fn cmd_help() puts("commands: help, clear, bars, echo <text>, time\n")

fn cmd_clear() do
  fill_rect(0, 0, fb_width(), fb_height(), CON_BG)
  con.col = 0
  con.row = 0
end

fn cmd_bars() do
  const bars = { 0xff5555, 0xffaa00, 0xffff55, 0x55ff55, 0x55ffff, 0x5599ff, 0xaa55ff, 0xffffff }
  const bw = fb_width() / 8
  for i in 0..8 do fill_rect(i * bw, 0, bw, 40, bars[i]) end
  puts("painted 8 bars from revo\n")
end

fn bcd(b) (b shr 4) * 10 + (b band 15)
fn rtc(reg) do
  outb(0x70, reg)
  inb(0x71)
end
fn cmd_time() puts("utc " ~ bcd(rtc(4)) ~ ":" ~ bcd(rtc(2)) ~ ":" ~ bcd(rtc(0)) ~ "\n")

fn run(line) do
  const words = line:split(" ")
  const cmd = words[0]
  if cmd == "help" do cmd_help() end
  else if cmd == "clear" do cmd_clear() end
  else if cmd == "bars" do cmd_bars() end
  else if cmd == "time" do cmd_time() end
  else if cmd == "echo" do
    if line:len() > 5 puts(line:sub(5, line:len() - 5) ~ "\n") else puts("\n")
  end
  else if line:len() == 0 do :nil end
  else do puts("unknown command: " ~ cmd ~ "\n") end
  puts("> ")
end

# she stroke my keys till i handle
# no fr this is just a key stroke handler
global sh = { line = "" }
global on_key = fn(code) do
  if code >= 128 return :nil # key release
  if code == 28 do           # Enter
    puts("\n")
    run(sh.line)
    sh.line = ""
    return :nil
  end
  if code == 14 do           # Backspace
    if sh.line:len() > 0 do
      sh.line = sh.line:sub(0, sh.line:len() - 1)
      puts("\x08 \x08")
    end
    return :nil
  end
  if code < 2 return :nil
  if code >= KBD:len() return :nil
  const ch = KBD[code]
  sh.line = sh.line ~ ch
  puts(ch)
end

# kmain
pic_remap()
pic_unmask(1)
cmd_clear()
puts("revel shell, live in revo. type `help`\n> ")