#!/usr/bin/env python3

# Copyright 2021 The IREE Authors
#
# Licensed under the Apache License v2.0 with LLVM Exceptions.
# See https://llvm.org/LICENSE.txt for license information.
# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
"""Converts a dump of IR text to a markdown file with formatting.

Example usage:
  # Get a dump of IR from a compiler tool:
  $ iree-opt \
    --iree-transformation-pipeline \
    --iree-hal-target-backends=vmvx \
    --mlir-disable-threading \
    --mlir-print-ir-after-all \
    --mlir-print-ir-after-change \
    --mlir-elide-elementsattrs-if-larger=8 \
    $PWD/iree/samples/models/simple_abs.mlir \
    2> /tmp/simple_abs_vmvx_pipeline.mlir
    > /dev/null

  # Convert the IR dump to markdown:
  $ python3 ir_to_markdown.py \
    /tmp/simple_abs_vmvx_pipeline.mlir \
    -o /tmp/simple_abs_vmvx_pipeline.md
"""

import argparse
import re

MLIR_START_SEQUENCE = "// -----//"
MLIR_END_SEQUENCE = "//----- //"


def parse_arguments():
    """Parses command line arguments."""

    parser = argparse.ArgumentParser()
    parser.add_argument(
        "input_file_path",
        type=str,
        nargs="?",
        metavar="<input_file_path>",
        help="Input IR dump (.mlir from -mlir-print-ir-after-all)",
    )
    parser.add_argument(
        "-o,",
        "--output",
        type=str,
        required=True,
        metavar="<output>",
        help="Output file path (e.g. translation_ir.md)",
    )
    # TODO(scotttodd): flags for original IR path and compilation command line
    #                  .md could then show original IR + flags -> output
    # TODO(scotttodd): flag for markdown flavor (mkdocs, github, etc.)
    # TODO(scotttodd): flag for diff view (correlate IR before and IR after)?

    return parser.parse_args()


def main(args):
    input_file_path = args.input_file_path
    output_file_path = args.output
    print("Converting input file '%s'" % (input_file_path))
    print("     into output file '%s'" % (output_file_path))

    with open(input_file_path, "r") as input_file:
        with open(output_file_path, "w") as output_file:
            # Iterate line by line through the input file, collecting text into
            # blocks and writing them into the output file with markdown formatting
            # as we go.
            #
            # Note: we could parse through and find/replace within the file using
            # regex (or sed), but iterating this way is easier to understand and
            # uses a predictable amount of memory.

            current_block_lines = []
            dump_after_regex = re.compile(
                MLIR_START_SEQUENCE + "\s(.*)\s" + MLIR_END_SEQUENCE
            )

            def finish_block():
                nonlocal current_block_lines
                if len(current_block_lines) != 0:
                    current_block_lines.append("```\n\n")
                    output_file.writelines(current_block_lines)
                    current_block_lines = []

            for input_line in input_file:
                if input_line == "\n":
                    continue

                if input_line.startswith(MLIR_START_SEQUENCE):
                    finish_block()
                    header_text = dump_after_regex.match(input_line).group(1)
                    current_block_lines.append("### " + header_text + "\n\n")
                    current_block_lines.append("```mlir\n")
                else:
                    current_block_lines.append(input_line)

            finish_block()


if __name__ == "__main__":
    main(parse_arguments())