From 9376ed14f98c73d5d145ab48878bb0b2a4eb7f4c Mon Sep 17 00:00:00 2001
From: prod2 <prod2@norlang.art>
Date: Wed, 28 Dec 2022 23:55:34 +0100
Subject: [PATCH] ctrl+c, ctrl+d, start of a buffer lib

---
 termBuffer/buffer.nim          | 134 +++++++++++++++++++++++++++++++++
 termBuffer/escapeSequences.nim |  14 ++++
 2 files changed, 148 insertions(+)
 create mode 100644 termBuffer/buffer.nim
 create mode 100644 termBuffer/escapeSequences.nim

diff --git a/termBuffer/buffer.nim b/termBuffer/buffer.nim
new file mode 100644
index 0000000..be68fe7
--- /dev/null
+++ b/termBuffer/buffer.nim
@@ -0,0 +1,134 @@
+import unicode
+import escapeSequences
+
+type
+  Buffer* = ref object
+    # AS IS ON SCREEN VALUES
+    stdout: File # usually you want to put stdout here
+    displayed: seq[Cell]
+    displayX, displayY: int # where the cursor is on display
+    positionX, positionY: int # where the buffer's top left corner is
+
+    # SIMULATED VALUES
+    buffered: seq[Cell]
+    # cursor position
+    bufferX, bufferY: int # where the cursor is, in buffer
+    width, height: int
+    # current style we're writing with
+    cursorAttributes: seq[uint8]
+
+  ForegroundColors* = enum
+    fcBlack = 30, fcRed, fcGreen, fcYellow, fcBlue,
+    fcMagenta, fcCyan, fcLightGray,
+    fcDefault = 39,
+    fcDarkGray = 90, fcLightRed, fcLightGreen,
+    fcLightYellow, fcLightBlue, fcLightMagenta,
+    fcLightCyan, fcWhite
+  BackgroundColors* = enum
+    bcBlack, bcRed, bcGreen, bcYellow, bcBlue, 
+    bcMagenta, bcCyan, bcLightGray,
+    bcDefault = 49,
+    bcDarkGray = 100, bcLightRed, bcLightGreen,
+    bcLightYellow, bcLightBlue, bcLightMagenta,
+    bcLightCyan, bcWhite
+  FontStyle* = enum
+    # these two are the most widely supported
+    fsReset = 0,
+    fsBold = 1,
+    fsUnderlined = 4,
+  Cell = object
+    attributes: seq[uint8]
+    text: Rune
+
+func getCursorPos*(buf: Buffer): (int, int) =
+  (buf.bufferX, buf.bufferY)
+
+proc setCursorPos*(buf: Buffer, x, y: int) =
+  if x < 0 or y < 0 or x >= buf.width or y >= buf.height:
+    raise newException(ValueError, "Provided x or y out of bounds for SetCursorPos.")
+  buf.bufferX = x
+  buf.bufferY = y
+
+func getCursorXPos*(buf: Buffer): int =
+  buf.bufferX
+
+proc setCursorXPos*(buf: Buffer, x: int) =
+  if x < 0 or x >= buf.width:
+    raise newException(ValueError, "Provided x is out of bounds.")
+  buf.bufferX = x
+
+
+proc setAttributes*(buf: Buffer, attributes: seq[uint8]) =
+  buf.cursorAttributes = attributes
+
+proc addAttribute*(buf: Buffer, attribute: uint8) =
+  buf.cursorAttributes.add(attribute)
+
+proc clearAttributes*(buf: Buffer) =
+  buf.cursorAttributes = @[]
+  
+proc clear*(buf: Buffer) =
+  for i in 0..buf.buffered.high():
+    buf.buffered[i] = Cell(text: Rune(0))
+  buf.bufferX = 0
+  buf.bufferY = 0
+
+template lineStart(buf: Buffer, line: int): int =
+  # returns where line <line> starts
+  buf.width * line
+
+template lineEnd(buf: Buffer, line: int): int =
+  buf.lineStart(line + 1) - 1
+
+proc clearLine*(buf: Buffer) =
+  for i in buf.lineStart(buf.bufferY)..buf.lineEnd(buf.bufferY):
+    buf.buffered[i] = Cell(text: Rune(0))
+  buf.bufferX = 0
+
+proc write*(buf: Buffer, text: string) =
+  # convert text to characters
+  let runes = text.toRunes()
+
+  # if it would go out of the screen, crash
+  if buf.bufferX + runes.len() >= buf.width:
+    raise newException(ValueError, "Text too long, would overflow the buffer.")
+
+  let fromPos = buf.lineStart(buf.bufferY) + buf.bufferX
+  let toPos = fromPos + runes.high()
+
+  for i in fromPos..toPos:
+    buf.buffered[i] = Cell(text: runes[i-fromPos], attributes: buf.cursorAttributes)
+  
+
+proc redraw*(buf: Buffer) =
+  var toPrint = ""
+  # save cursor state
+  let oldDisplayX = buf.displayX
+  let oldDisplayY = buf.displayY
+
+  # go over display and buffer to find any differences
+  for i in 0..buf.buffered.high():
+    let cellBuffer = buf.buffered[i]
+    let cellDisplay = buf.displayed[i]
+    # TODO continue here :)
+
+
+
+
+  # finish
+  toPrint &= escCursorPos(oldDisplayX, oldDisplayY)
+  buf.stdout.write(toPrint)
+  
+
+func getSize*(buf: Buffer): (int, int) =
+  (buf.width, buf.height)
+
+proc resize*(buf: Buffer, newX, newY: int) =
+  raise newException(Defect, "Not implemented")
+
+func getPosition*(buf: Buffer): (int, int) =
+  (buf.positionX, buf.positionY)
+
+proc setPosition*(buf: Buffer, x, y: int) =
+  buf.positionX = x
+  buf.positionY = y
\ No newline at end of file
diff --git a/termBuffer/escapeSequences.nim b/termBuffer/escapeSequences.nim
new file mode 100644
index 0000000..c292752
--- /dev/null
+++ b/termBuffer/escapeSequences.nim
@@ -0,0 +1,14 @@
+# list of functions to generate escape sequences
+
+import strformat
+import strutils
+
+func escCursorPos*(x, y: int): string =
+  &"\e[{x+1};{y+1}H"
+
+func escAttributes*(attributes: seq[uint8]): string =
+  let joined = attributes.join(";")
+  &"\e[{joined}m"
+
+func escEraseCharacters*(n: int): string =
+  &"\e[{n}X"
\ No newline at end of file