Internal logic rewrite, CLI and lib split, used click over argparse

- Rewrote the tags parsing logic. The previous one was based on the
  on-demand, separate, atomic message parsing for each tag operation. It
  was kinda raw and liberal, avoiding building additional data
  structures. The goal was to keep it flexible, but it turned out to be
  too flexible, recognizing parts of upstream message as CIQ tags, like
  in the case of the commit 081056dc00a27bccb55ccc3c6f230a3d5fd3f7e0. In
  the new version the CIQ tags are required to consitute a continuous
  block at the very beginning of git message. The message is parsed in
  whole, all tags tracked no matter what operation on which of them is
  requested. An explicit list of tags for the given commit message is
  build, which allows for simplification of a lot of editing code. From
  the API perspective there is no longer a loose bag of functions but a
  CiqMsg class encapsulating the operations as modifier methods, with
  the `get_message()' getter method to obtain the end result of all
  carried out operations (adding/editing/deleting tags). The command
  line interface remained exactly the same.
- Extracted the CLI to a separate file
  ciq_tag.py: library
  ciq-tag.py: executable CLI
- Rewrote arguments parsing from argpars to click

Author: pvts-mat

ciq-tag.py

@@ -0,0 +1,297 @@
+#!/usr/bin/env python3
+
+import ciq_tag
+import click
+import os
+from enum import Enum
+import sys
+import logging
+
+DEFAULT_LOGLEVEL = "INFO"
+
+LOGLEVEL = os.environ.get("LOGS", DEFAULT_LOGLEVEL).upper()
+logger = logging.getLogger(__name__)
+logger.propagate = False
+logger.setLevel(LOGLEVEL)
+log_handler = logging.StreamHandler()
+log_handler.setFormatter(logging.Formatter("%(levelname)s:%(name)s:%(funcName)s: %(message)s"))
+logger.addHandler(log_handler)
+
+
+CIQ_TAGS_LIST = ", ".join(c.arg_name for c in ciq_tag.CiqTag)
+
+
+class CmdException(Exception):
+    def __init__(self, exit_code, *rest):
+        super().__init__(*rest)
+        self._exit_code = exit_code
+
+
+def open_input(filename, **rest):
+    return sys.stdin if filename == "-" else open(filename, "r", **rest)
+
+
+def open_output(filename, **rest):
+    return sys.stdout if filename == "-" else open(filename, "w", **rest)
+
+
+def process_in_out(input, output, result_to_output_map, ciq_msg_method, *method_args_pos, **method_args_key):
+    with open_input(input) as in_file:
+        input_str = "".join(in_file.readlines())
+        with open_output(output) as out_file:
+            msg = ciq_tag.CiqMsg(input_str)
+            ret, out = result_to_output_map(msg, ciq_msg_method(msg, *method_args_pos, **method_args_key))
+            if out:
+                print(out, file=out_file, end="")
+            if ret != 0:
+                raise CmdException(ret)
+
+
+def parse_tag(tag_name):
+    tag = ciq_tag.CiqTag.get_by_arg_name(tag_name)
+    if tag:
+        return tag
+    else:
+        raise CmdException(1, f"Wrong TAG value. Must be one of: {CIQ_TAGS_LIST}")
+
+
+def read_value(value_arg, val_from_file_arg, trim_arg):
+    if val_from_file_arg:
+        with open_input(value_arg) as inFile:
+            value = "".join(inFile.readlines())
+    else:
+        value = value_arg
+    return value.strip() if trim_arg else value
+
+
+def getter_map(msg, result):
+    return (0, result + "\n") if result else (1, "")
+
+
+def setter_map(msg, modified):
+    out = msg.get_message()
+    return (0, out) if modified else (1, out)
+
+
+def args(*positional, **keyword):
+    return (positional, keyword)
+
+
+class ClickDef(Enum):
+    TAG = args("tag", type=str)
+
+    VALUE = args("value", type=str)
+
+    INDEX = args("index", type=int, required=False, default=0)
+
+    VAL_FROM_FILE = args(
+        "--val-from-file",
+        "-f",
+        flag_value=True,
+        help="""
+Treat the VALUE argument as a path to a file from which an actual value will be read (useful for
+multi-line formatted texts)
+""",
+    )
+
+    TRIM = args(
+        "--trim",
+        "-t",
+        flag_value=(not ciq_tag.DEFAULT_TRIM),
+        help="""
+Trim the value from whitespaces at the beginning and end before inserting to a commit message as a
+tag value. Useful when reading the tag value from a file, which can have trailing newlines
+""",
+    )
+
+    INDENT = args(
+        "--indent",
+        "-t",
+        type=int,
+        default=ciq_tag.DEFAULT_INDENT,
+        help="""
+When inserting multi-line values indent them by this many spaces. Special value -1 means value
+indenting equal to the width of the tag keyword.
+""",
+    )
+
+    DEDENT = args("--dedent", "-T", flag_value=True, help="For the multi-line value remove the indent, if it has any.")
+
+    WRAP = args("--wrap", "-w", flag_value=(not ciq_tag.DEFAULT_INDENT), help="Enable value wrapping")
+
+    UNWRAP = args("--unwrap", "-W", flag_value=True, help="Unwrap multi-line values to a single line. Implies DEDENT.")
+
+    WRAP_WIDTH = args(
+        "--wrap-width",
+        "-c",
+        type=int,
+        default=ciq_tag.DEFAULT_WRAP_WIDTH,
+        help="If WRAP flag is given wrap the value text to this many columns.",
+    )
+
+    def __init__(self, positional, keyword):
+        self.positional = positional
+        self.keyword = keyword
+
+
+OPTIONS = {}
+
+
+@click.group(context_settings=dict(help_option_names=["-h", "--help"]))
+@click.option(
+    "--input", "-i", type=click.Path(), default="-", show_default=True, help="File path to read, or '-' for stdin"
+)
+@click.option(
+    "--output", "-o", type=click.Path(), default="-", show_default=True, help="File path to write, or '-' for stdout"
+)
+def cli(input, output):
+    OPTIONS["input"] = input
+    OPTIONS["output"] = output
+
+
+@cli.command(
+    "get",
+    help=f"""
+Print to the output (--output) the value of the INDEXth TAG in the commit message given on
+the input (--input). If INDEX is not given assume it's 0, which is the first occurence of
+the TAG. Exit with nonzero if TAG not found. TAG can be one of: {CIQ_TAGS_LIST}
+""",
+)
+@click.argument(*ClickDef.TAG.positional, **ClickDef.TAG.keyword)
+@click.argument(*ClickDef.INDEX.positional, **ClickDef.INDEX.keyword)
+@click.option(*ClickDef.UNWRAP.positional, **ClickDef.UNWRAP.keyword)
+@click.option(*ClickDef.DEDENT.positional, **ClickDef.DEDENT.keyword)
+def command_get(tag, index, unwrap, dedent):
+    process_in_out(
+        OPTIONS["input"],
+        OPTIONS["output"],
+        getter_map,
+        ciq_tag.CiqMsg.get_tag_value,
+        parse_tag(tag),
+        index,
+        unwrap=unwrap,
+        dedent=dedent,
+    )
+
+
+@cli.command(
+    "modify",
+    help="""
+Set the value of TAG, in its current place, using the current keyword. Return nonzero if the TAG
+wasn't defined already.
+""",
+)
+@click.argument(*ClickDef.TAG.positional, **ClickDef.TAG.keyword)
+@click.argument(*ClickDef.VALUE.positional, **ClickDef.VALUE.keyword)
+@click.argument(*ClickDef.INDEX.positional, **ClickDef.INDEX.keyword)
+@click.option(*ClickDef.VAL_FROM_FILE.positional, **ClickDef.VAL_FROM_FILE.keyword)
+@click.option(*ClickDef.TRIM.positional, **ClickDef.TRIM.keyword)
+@click.option(*ClickDef.INDENT.positional, **ClickDef.INDENT.keyword)
+@click.option(*ClickDef.WRAP.positional, **ClickDef.WRAP.keyword)
+@click.option(*ClickDef.WRAP_WIDTH.positional, **ClickDef.WRAP_WIDTH.keyword)
+def command_modify(tag, value, index, val_from_file, trim, indent, wrap, wrap_width):
+    process_in_out(
+        OPTIONS["input"],
+        OPTIONS["output"],
+        setter_map,
+        ciq_tag.CiqMsg.modify_tag_value,
+        parse_tag(tag),
+        read_value(value, val_from_file, trim),
+        index,
+        trim=trim,
+        indent=indent,
+        wrap=wrap,
+        wrap_width=wrap_width,
+    )
+
+
+@cli.command(
+    "add",
+    help="""
+Add a TAG with VALUE to the commit message. Attempt to locate the proper place to insert the tag then do it
+using the default keyword and value formatting defined by the options.
+""",
+)
+@click.argument(*ClickDef.TAG.positional, **ClickDef.TAG.keyword)
+@click.argument(*ClickDef.VALUE.positional, **ClickDef.VALUE.keyword)
+@click.option(*ClickDef.VAL_FROM_FILE.positional, **ClickDef.VAL_FROM_FILE.keyword)
+@click.option(*ClickDef.TRIM.positional, **ClickDef.TRIM.keyword)
+@click.option(*ClickDef.INDENT.positional, **ClickDef.INDENT.keyword)
+@click.option(*ClickDef.WRAP.positional, **ClickDef.WRAP.keyword)
+@click.option(*ClickDef.WRAP_WIDTH.positional, **ClickDef.WRAP_WIDTH.keyword)
+def command_add(tag, value, val_from_file, trim, indent, wrap, wrap_width):
+    process_in_out(
+        OPTIONS["input"],
+        OPTIONS["output"],
+        setter_map,
+        ciq_tag.CiqMsg.add_tag,
+        parse_tag(tag),
+        read_value(value, val_from_file, trim),
+        trim=trim,
+        indent=indent,
+        wrap=wrap,
+        wrap_width=wrap_width,
+    )
+
+
+@cli.command(
+    "set",
+    help="""
+Attempt to set TAG to the VALUE in place as it would be done with the 'modify' action, using INDEX
+(default 0). If that fails insert it as with the 'add' action.
+""",
+)
+@click.argument(*ClickDef.TAG.positional, **ClickDef.TAG.keyword)
+@click.argument(*ClickDef.VALUE.positional, **ClickDef.VALUE.keyword)
+@click.argument(*ClickDef.INDEX.positional, **ClickDef.INDEX.keyword)
+@click.option(*ClickDef.VAL_FROM_FILE.positional, **ClickDef.VAL_FROM_FILE.keyword)
+@click.option(*ClickDef.TRIM.positional, **ClickDef.TRIM.keyword)
+@click.option(*ClickDef.INDENT.positional, **ClickDef.INDENT.keyword)
+@click.option(*ClickDef.WRAP.positional, **ClickDef.WRAP.keyword)
+@click.option(*ClickDef.WRAP_WIDTH.positional, **ClickDef.WRAP_WIDTH.keyword)
+def command_set(tag, value, index, val_from_file, trim, indent, wrap, wrap_width):
+    process_in_out(
+        OPTIONS["input"],
+        OPTIONS["output"],
+        setter_map,
+        ciq_tag.CiqMsg.set_tag,
+        parse_tag(tag),
+        read_value(value, val_from_file, trim),
+        index,
+        trim=trim,
+        indent=indent,
+        wrap=wrap,
+        wrap_width=wrap_width,
+    )
+
+
+@cli.command(
+    "delete",
+    help="""
+Delete a tag from the commit message. Attempt to keep the message formatted nicely.
+""",
+)
+@click.argument(*ClickDef.TAG.positional, **ClickDef.TAG.keyword)
+@click.argument(*ClickDef.INDEX.positional, **ClickDef.INDEX.keyword)
+def command_delete(tag, index):
+    process_in_out(
+        OPTIONS["input"],
+        OPTIONS["output"],
+        setter_map,
+        ciq_tag.CiqMsg.delete_tag,
+        ciq_tag.CiqTag.get_by_arg_name(tag),
+        index,
+    )
+
+
+def main():
+    try:
+        cli()
+        return 0
+    except CmdException as exc:
+        logger.error(str(exc))
+        return exc._exit_code
+
+
+if __name__ == "__main__":
+    exit(main())