#!/usr/bin/env python3
"""Verify the text maps and dictionaries consumed by strans."""

import argparse
import sys
from pathlib import Path


def verify(path):
	errors = []
	try:
		data = path.read_bytes()
	except OSError as error:
		return [f"{path}: {error.strerror}"]
	try:
		text = data.decode("utf-8")
	except UnicodeDecodeError as error:
		return [f"{path}: invalid UTF-8: {error}"]

	keys = {}
	for lineno, line in enumerate(text.split("\n"), 1):
		where = f"{path}:{lineno}"
		if "\r" in line:
			errors.append(f"{where}: carriage return is not canonical")
			line = line.replace("\r", "")
		if not line or line.startswith(";"):
			continue
		if "\0" in line:
			errors.append(f"{where}: embedded NUL")
		if line.count("\t") != 1:
			errors.append(f"{where}: expected exactly one tab")
			continue
		key, value = line.split("\t")
		if not key:
			errors.append(f"{where}: empty key")
		if len(key) > 64:
			errors.append(f"{where}: key has {len(key)} runes; maximum is 64")
		if key in keys:
			errors.append(f"{where}: duplicate key; first defined on line {keys[key]}")
		else:
			keys[key] = lineno
		if not value:
			errors.append(f"{where}: empty value")
			continue
		if value != " ".join(value.split(" ")):
			errors.append(f"{where}: noncanonical candidate spacing")
		values = value.split(" ")
		if len(values) != len(set(values)):
			errors.append(f"{where}: duplicate candidate")
	return errors


def main():
	parser = argparse.ArgumentParser(description=__doc__)
	parser.add_argument("file", nargs="+", type=Path)
	args = parser.parse_args()
	errors = []
	for path in args.file:
		errors.extend(verify(path))
	for error in errors:
		print(error, file=sys.stderr)
	return bool(errors)


if __name__ == "__main__":
	raise SystemExit(main())