1 files changed, 170 insertions, 0 deletions
diff --git a/src/gpt_chat_cli/prompt.py b/src/gpt_chat_cli/prompt.py
new file mode 100644
index 0000000..ec39b4b
--- /dev/null
+++ b/src/gpt_chat_cli/prompt.py
@@ -0,0 +1,170 @@
+from typing import List, Dict, Tuple
+from dataclasses import dataclass
+
+import os
+import sys
+import textwrap
+
+from .color import (
+    get_color_codes,
+    surround_ansi_escapes,
+    ColorCode
+)
+
+@dataclass
+class Command( object ):
+    name : str
+    description : str
+
+    # eventually could contain arguments
+
+PromptResponse = Tuple[Command, None] | Tuple[None, str]
+
+class PromptUsageException(Exception):
+    def __init__( self : "PromptUsageException", message : str):
+        self.message = message
+
+class Prompt( object ):
+
+    COMMAND_INDICATOR = "/"
+    SEP = ' '
+
+    def __init__(self : "Prompt", prompt : str, cmds : List[Command]):
+        self.prompt = prompt
+        self._cmds = { cmd.name : cmd for cmd in cmds }
+
+    def print_help( self : "Prompt", file=sys.stdout ):
+        cmds = list(self._cmds.values())
+        cmds.sort(key=lambda cmd: cmd.name)
+
+        COMMAND_HEADER = "Command"
+        DESCRIPTION_HEADER = "Description"
+
+        MAX_COLUMN_LEN = 80
+        SPACING = 2
+        SEP = SPACING * ' '
+
+        # Calculate column widths
+        name_width = max(len(cmd.name) for cmd in cmds)
+        name_width = max(len(COMMAND_HEADER), name_width)
+
+        desc_width = max(len(cmd.description) for cmd in cmds)
+        desc_width = max(len(DESCRIPTION_HEADER), desc_width)
+        desc_width = min(desc_width, MAX_COLUMN_LEN - SPACING - name_width)
+
+        # Print headers
+        print(f"{'Command':<{name_width}}{SEP}{'Description':<{desc_width}}", file=file)
+        print("-" * (name_width + desc_width + SPACING), file=file)
+
+        # Print rows
+        for cmd in cmds:
+            name = cmd.name.ljust(name_width)
+
+            desc_lines = textwrap.wrap(cmd.description, desc_width)
+            desc = ''
+            for i, desc_line in enumerate(desc_lines):
+                if i == 0:
+                    desc += desc_line + '\n'
+                else:
+                    desc += ' ' * (SPACING + name_width)
+                    desc += desc_line + '\n'
+
+            print(f"{name}{SEP}{desc}", file=file, end='')
+
+        print()
+
+    def _parse_response( self : "Prompt", response : str) \
+            -> PromptResponse:
+
+        if not response.startswith(Prompt.COMMAND_INDICATOR):
+            return (None, response)
+
+        cmd_parts = response[1:].split(sep=Prompt.SEP)
+        cmd_name = cmd_parts[0].strip()
+
+        if cmd_name not in self._cmds:
+            raise PromptUsageException(f'command not found: {cmd_name}')
+
+        cmd = self._cmds[cmd_name]
+
+        return (cmd, None)
+
+    def input( self : "Prompt" ):
+        while True:
+            try:
+                raw_input = input(self.prompt)
+                response = self._parse_response( raw_input )
+                return response
+            except PromptUsageException as e:
+                print(f'error: {e.message}', file=sys.stderr)
+
+class Prompter( object ):
+
+    _cmds : Dict[str, Command]
+
+    def __init__( self : "Prompter", no_color=False ):
+        self._cmds = []
+        self._COLOR = get_color_codes( no_color=no_color )
+        self._PROMPT = surround_ansi_escapes(
+            f'[{self._COLOR.WHITE}#{self._COLOR.RESET}] '
+        )
+        self._prev_completer_delims = None
+
+    def add_command( self : "Prompter", name : str, description : str ):
+        cmd = Command(name, description)
+        self._cmds.append(cmd)
+        return cmd
+
+    def _enable_prompting( self : "Prompter" ):
+
+        try:
+            import readline as rl
+
+            def completer( text, state ):
+
+                # stop completions when slash commands
+                # are not specified
+                buffer = rl.get_line_buffer()
+
+                if len(buffer) == 0 or buffer[0] != '/':
+                    return None
+
+                completion_options = [ cmd.name for cmd in self._cmds ]
+
+                options = [ i for i in completion_options if i.startswith(text) ]
+
+                if state < len(options):
+                    return options[state]
+                else:
+                    return None
+
+            rl.set_completer(completer)
+            self._prev_completer_delims = rl.get_completer_delims()
+            rl.set_completer_delims('/')
+            rl.parse_and_bind('tab: complete')
+
+        except ImportError:
+            pass
+
+    def _disable_prompting(self : "Prompter"):
+
+        # try our best to clean up
+        try:
+            import readline as rl
+
+            rl.set_completer(None)
+            rl.parse_and_bind('tab: insert-tab')
+            rl.set_completer_delims(self._prev_completer_delims)
+
+        except ImportError:
+            pass
+
+    def __enter__(self : "Prompter"):
+        self._enable_prompting()
+        return Prompt(self._PROMPT, self._cmds)
+
+    def __exit__(self : "Prompter", exec_type, exec_val, exc_tb):
+        self._disable_prompting()
+
+
+