1 files changed, 175 insertions, 0 deletions
diff --git a/ui/Root.js b/ui/Root.js
new file mode 100644
index 0000000..06e3ecd
--- /dev/null
+++ b/ui/Root.js
@@ -0,0 +1,175 @@
+const iac = require('iac')
+
+const ansi = require('../ansi')
+
+const DisplayElement = require('./DisplayElement')
+
+const FocusElement = require('./form/FocusElement')
+
+module.exports = class Root extends DisplayElement {
+  // An element to be used as the root of a UI. Handles lots of UI and
+  // socket stuff.
+
+  constructor(socket) {
+    super()
+
+    this.socket = socket
+    this.initTelnetOptions()
+
+    this.selected = null
+
+    this.cursorBlinkOffset = Date.now()
+
+    socket.on('data', buf => this.handleData(buf))
+  }
+
+  initTelnetOptions() {
+    // Initializes various socket options, using telnet magic.
+
+    // Disables linemode.
+    this.socket.write(Buffer.from([
+      255, 253, 34,  // IAC DO LINEMODE
+      255, 250, 34, 1, 0, 255, 240,  // IAC SB LINEMODE MODE 0 IAC SE
+      255, 251, 1    // IAC WILL ECHO
+    ]))
+
+    // Will SGA. Helps with putty apparently.
+    this.socket.write(Buffer.from([
+      255, 251, 3  // IAC WILL SGA
+    ]))
+
+    this.socket.write(ansi.hideCursor())
+  }
+
+  cleanTelnetOptions() {
+    // Resets the telnet options and magic set in initTelnetOptions.
+
+    this.socket.write(ansi.resetAttributes())
+    this.socket.write(ansi.showCursor())
+  }
+
+  requestTelnetWindowSize() {
+    // See RFC #1073 - Telnet Window Size Option
+
+    return new Promise((res, rej) => {
+      this.socket.write(Buffer.from([
+        255, 253, 31  // IAC WILL NAWS
+      ]))
+
+      this.once('telnetsub', function until(sub) {
+        if (sub[0] !== 31) { // NAWS
+          this.once('telnetsub', until)
+        } else {
+          res({lines: sub[4], cols: sub[2]})
+        }
+      })
+    })
+  }
+
+  handleData(buffer) {
+    if (buffer[0] === 255) {
+      // Telnet IAC (Is A Command) - ignore
+
+      // Split the data into multiple IAC commands if more than one IAC was
+      // sent.
+      const values = Array.from(buffer.values())
+      const commands = []
+      const curCmd = [255]
+      for (let value of values) {
+        if (value === 255) { // IAC
+          commands.push(Array.from(curCmd))
+          curCmd.splice(1, curCmd.length)
+          continue
+        }
+        curCmd.push(value)
+      }
+      commands.push(curCmd)
+
+      for (let command of commands) {
+        this.interpretTelnetCommand(command)
+      }
+
+      return
+    }
+
+    if (this.selected) {
+      const els = this.selected.directAncestors.concat([this.selected])
+      for (let el of els) {
+        if (el instanceof FocusElement) {
+          const shouldBreak = (el.keyPressed(buffer) === false)
+          if (shouldBreak) {
+            break
+          }
+          el.emit('keypressed', buffer)
+        }
+      }
+    }
+  }
+
+  interpretTelnetCommand(command) {
+    if (command[0] !== 255) { // IAC
+      // First byte isn't IAC, which means this isn't a command, so do
+      // nothing.
+      return
+    }
+
+    if (command[1] === 251) { // WILL
+      // Do nothing because I'm lazy
+      const willWhat = command[2]
+      //console.log('IAC WILL ' + willWhat)
+    }
+
+    if (command[1] === 250) { // SB
+      this.telnetSub = command.slice(2)
+    }
+
+    if (command[1] === 240) { // SE
+      this.emit('telnetsub', this.telnetSub)
+      this.telnetSub = null
+    }
+  }
+
+  drawTo(writable) {
+    writable.write(ansi.moveCursor(0, 0))
+    writable.write(' '.repeat(this.w * this.h))
+  }
+
+  didRenderTo(writable) {
+    // Render the cursor, based on the cursorX and cursorY of the currently
+    // selected element.
+    if (
+      this.selected &&
+      typeof this.selected.cursorX === 'number' &&
+      typeof this.selected.cursorY === 'number' &&
+      (Date.now() - this.cursorBlinkOffset) % 1000 < 500
+    ) {
+      writable.write(ansi.moveCursor(
+        this.selected.absCursorY, this.selected.absCursorX))
+      writable.write(ansi.invert())
+      writable.write('I')
+      writable.write(ansi.resetAttributes())
+    }
+    writable.write(ansi.moveCursor(0, 0))
+  }
+
+  cursorMoved() {
+    // Resets the blinking animation for the cursor. Call this whenever you
+    // move the cursor.
+
+    this.cursorBlinkOffset = Date.now()
+  }
+
+  select(el) {
+    // Select an element. Calls the unfocus method on the already-selected
+    // element, if there is one.
+
+    if (this.selected) {
+      this.selected.unfocus()
+    }
+
+    this.selected = el
+    this.selected.focus()
+
+    this.cursorMoved()
+  }
+}