# This file is a minimal clang-include-fixer vim-integration. To install:
# - Change 'binary' if clang-include-fixer is not on the path (see below).
# - Add to your .vimrc:
#
#   noremap <leader>cf :pyf path/to/llvm/source/tools/clang/tools/extra/clang-include-fixer/tool/clang-include-fixer.py<cr>
#
# This enables clang-include-fixer for NORMAL and VISUAL mode. Change
# "<leader>cf" to another binding if you need clang-include-fixer on a
# different key.
#
# To set up clang-include-fixer, see
# http://clang.llvm.org/extra/clang-include-fixer.html
#
# With this integration you can press the bound key and clang-include-fixer will
# be run on the current buffer.
#
# It operates on the current, potentially unsaved buffer and does not create
# or save any files. To revert a fix, just undo.

from __future__ import print_function
import argparse
import difflib
import json
import re
import subprocess
import vim

# set g:clang_include_fixer_path to the path to clang-include-fixer if it is not
# on the path.
# Change this to the full path if clang-include-fixer is not on the path.
binary = "clang-include-fixer"
if vim.eval('exists("g:clang_include_fixer_path")') == "1":
    binary = vim.eval("g:clang_include_fixer_path")

maximum_suggested_headers = 3
if vim.eval('exists("g:clang_include_fixer_maximum_suggested_headers")') == "1":
    maximum_suggested_headers = max(
        1, vim.eval("g:clang_include_fixer_maximum_suggested_headers")
    )

increment_num = 5
if vim.eval('exists("g:clang_include_fixer_increment_num")') == "1":
    increment_num = max(1, vim.eval("g:clang_include_fixer_increment_num"))

jump_to_include = False
if vim.eval('exists("g:clang_include_fixer_jump_to_include")') == "1":
    jump_to_include = vim.eval("g:clang_include_fixer_jump_to_include") != "0"

query_mode = False
if vim.eval('exists("g:clang_include_fixer_query_mode")') == "1":
    query_mode = vim.eval("g:clang_include_fixer_query_mode") != "0"


def GetUserSelection(message, headers, maximum_suggested_headers):
    eval_message = message + "\n"
    for idx, header in enumerate(headers[0:maximum_suggested_headers]):
        eval_message += "({0}). {1}\n".format(idx + 1, header)
    eval_message += "Enter (q) to quit;"
    if maximum_suggested_headers < len(headers):
        eval_message += " (m) to show {0} more candidates.".format(
            min(increment_num, len(headers) - maximum_suggested_headers)
        )

    eval_message += "\nSelect (default 1): "
    res = vim.eval("input('{0}')".format(eval_message))
    if res == "":
        # choose the top ranked header by default
        idx = 1
    elif res == "q":
        raise Exception("   Insertion cancelled...")
    elif res == "m":
        return GetUserSelection(
            message, headers, maximum_suggested_headers + increment_num
        )
    else:
        try:
            idx = int(res)
            if idx <= 0 or idx > len(headers):
                raise Exception()
        except Exception:
            # Show a new prompt on invalid option instead of aborting so that users
            # don't need to wait for another clang-include-fixer run.
            print("Invalid option: {}".format(res), file=sys.stderr)
            return GetUserSelection(message, headers, maximum_suggested_headers)
    return headers[idx - 1]


def execute(command, text):
    # Avoid flashing a cmd prompt on Windows.
    startupinfo = None
    if sys.platform.startswith("win32"):
        startupinfo = subprocess.STARTUPINFO()
        startupinfo.dwFlags |= subprocess.STARTF_USESHOWWINDOW
        startupinfo.wShowWindow = subprocess.SW_HIDE

    p = subprocess.Popen(
        command,
        stdout=subprocess.PIPE,
        stderr=subprocess.PIPE,
        stdin=subprocess.PIPE,
        startupinfo=startupinfo,
    )
    return p.communicate(input=text.encode("utf-8"))


def InsertHeaderToVimBuffer(header, text):
    command = [
        binary,
        "-stdin",
        "-insert-header=" + json.dumps(header),
        vim.current.buffer.name,
    ]
    stdout, stderr = execute(command, text)
    if stderr:
        raise Exception(stderr)
    if stdout:
        lines = stdout.splitlines()
        sequence = difflib.SequenceMatcher(None, vim.current.buffer, lines)
        line_num = None
        for op in reversed(sequence.get_opcodes()):
            if op[0] != "equal":
                vim.current.buffer[op[1] : op[2]] = lines[op[3] : op[4]]
            if op[0] == "insert":
                # line_num in vim is 1-based.
                line_num = op[1] + 1

        if jump_to_include and line_num:
            vim.current.window.cursor = (line_num, 0)


# The vim internal implementation (expand("cword"/"cWORD")) doesn't support
# our use case very well, we re-implement our own one.
def get_symbol_under_cursor():
    line = vim.eval('line(".")')
    # column number in vim is 1-based.
    col = int(vim.eval('col(".")')) - 1
    line_text = vim.eval("getline({0})".format(line))
    if len(line_text) == 0:
        return ""
    symbol_pos_begin = col
    p = re.compile("[a-zA-Z0-9:_]")
    while symbol_pos_begin >= 0 and p.match(line_text[symbol_pos_begin]):
        symbol_pos_begin -= 1

    symbol_pos_end = col
    while symbol_pos_end < len(line_text) and p.match(line_text[symbol_pos_end]):
        symbol_pos_end += 1
    return line_text[symbol_pos_begin + 1 : symbol_pos_end]


def main():
    parser = argparse.ArgumentParser(
        description="Vim integration for clang-include-fixer"
    )
    parser.add_argument("-db", default="yaml", help="clang-include-fixer input format.")
    parser.add_argument("-input", default="", help="String to initialize the database.")
    # Don't throw exception when parsing unknown arguments to make the script
    # work in neovim.
    # Neovim (at least v0.2.1) somehow mangles the sys.argv in a weird way: it
    # will pass additional arguments (e.g. "-c script_host.py") to sys.argv,
    # which makes the script fail.
    args, _ = parser.parse_known_args()

    # Get the current text.
    buf = vim.current.buffer
    text = "\n".join(buf)

    if query_mode:
        symbol = get_symbol_under_cursor()
        if len(symbol) == 0:
            print("Skip querying empty symbol.")
            return
        command = [
            binary,
            "-stdin",
            "-query-symbol=" + get_symbol_under_cursor(),
            "-db=" + args.db,
            "-input=" + args.input,
            vim.current.buffer.name,
        ]
    else:
        # Run command to get all headers.
        command = [
            binary,
            "-stdin",
            "-output-headers",
            "-db=" + args.db,
            "-input=" + args.input,
            vim.current.buffer.name,
        ]
    stdout, stderr = execute(command, text)
    if stderr:
        print(
            "Error while running clang-include-fixer: {}".format(stderr),
            file=sys.stderr,
        )
        return

    include_fixer_context = json.loads(stdout)
    query_symbol_infos = include_fixer_context["QuerySymbolInfos"]
    if not query_symbol_infos:
        print("The file is fine, no need to add a header.")
        return
    symbol = query_symbol_infos[0]["RawIdentifier"]
    # The header_infos is already sorted by clang-include-fixer.
    header_infos = include_fixer_context["HeaderInfos"]
    # Deduplicate headers while keeping the order, so that the same header would
    # not be suggested twice.
    unique_headers = []
    seen = set()
    for header_info in header_infos:
        header = header_info["Header"]
        if header not in seen:
            seen.add(header)
            unique_headers.append(header)

    if not unique_headers:
        print("Couldn't find a header for {0}.".format(symbol))
        return

    try:
        selected = unique_headers[0]
        inserted_header_infos = header_infos
        if len(unique_headers) > 1:
            selected = GetUserSelection(
                "choose a header file for {0}.".format(symbol),
                unique_headers,
                maximum_suggested_headers,
            )
            inserted_header_infos = [
                header for header in header_infos if header["Header"] == selected
            ]
        include_fixer_context["HeaderInfos"] = inserted_header_infos

        InsertHeaderToVimBuffer(include_fixer_context, text)
        print("Added #include {0} for {1}.".format(selected, symbol))
    except Exception as error:
        print(error, file=sys.stderr)
    return


if __name__ == "__main__":
    main()