#!/usr/bin/env bash

# Copyright (c) eBPF for Windows contributors
# SPDX-License-Identifier: MIT

##==============================================================================
##
## Echo if verbose flag (ignores quiet flag)
##
##==============================================================================
log_verbose()
{
    if [[ ${verbose} -eq 1 ]]; then
        echo "$1"
    fi
}

##==============================================================================
##
## Echo if whatif flag is specified but not quiet flag
##
##==============================================================================
log_whatif()
{
    if [[ ${whatif} -eq 1 && ${quiet} -ne 1 ]]; then
        echo "$1"
    fi
}

##==============================================================================
##
## Process command-line options:
##
##==============================================================================

for opt in "$@"
do
  case $opt in
    -h | --help)
        usage=1
        ;;

    -v | --verbose)
        verbose=1
        ;;

    -q | --quiet)
        quiet=1
        ;;

    -w | --whatif)
        whatif=1
        ;;

    -s | --staged)
        # Split into array
        mapfile -t userFiles <<< "$(git diff --cached --name-only --diff-filter=ACMR)"
        ;;

    --exclude-dirs=*)
        userExcludeDirs="${opt#*=}"
        ;;

    --include-exts=*)
        userIncludeExts="${opt#*=}"
        ;;

    --files=*)
        read -ra userFiles <<< "${opt#*=}"
        ;;
    *)
        echo "$0: unknown option:  $opt"
        exit 1
        ;;
  esac
done

##==============================================================================
##
## Display help
##
##==============================================================================

if [[ ${usage} -eq 1 ]]; then
    cat<<EOF

OVERVIEW:

Formats all C/C++ source files based on the .clang-format rules

    $ format-code [-h] [-q] [-s] [-v] [-w] [--exclude-dirs="..."] [--include-exts="..."] [--files="..."]

OPTIONS:
    -h, --help              Print this help message.
    -q, --quiet             Display only clang-format output and errors.
    -s, --staged            Only format files which are staged to be committed.
    -v, --verbose           Display verbose output.
    -w, --whatif            Run the script without actually modifying the files
                            and display the diff of expected changes, if any.
    --exclude-dirs          Subdirectories to exclude. If unspecified, then
                            ./external, ./packages and ./x64 are excluded.
                            All subdirectories are relative to the current path.
    --include-exts          File extensions to include for formatting. If
                            unspecified, then *.h, *.hpp, *.c, *.cpp, *idl, and
                             *.acf are included.
    --files                 Only run the script against the specified files from
                            the current directory.

EXAMPLES:

To determine what lines of each file in the default configuration would be
modified by format-code, you can run from the root folder:

    $ ./scripts/format-code -w

To update only all .c and .cpp files in src/ except for src/tools/netsh, you
can run from the src folder:

    src$ ../scripts/format-code --exclude-dirs="tools/netsh" \
      --include-exts="c cpp"

To run only against a specified set of comma separated files in the current directory:

    $ ./scripts/format-code -w --files="file1 file2"

EOF
    exit 0
fi

##==============================================================================
##
## Check for acceptable version of clang-format
##
##==============================================================================
check_version()
{
    # shellcheck disable=SC2206
    v1=(${1//./ })
    # shellcheck disable=SC2206
    v2=(${2//./ })
    if [[ ${#v1[@]} -ne ${#v2[@]} ]]; then
        echo "Cannot parse clang-format version number: $2"
        exit 1
    fi
    for ((i=0; i<${#v1[@]}; i++));
    do
        # Because clang-format is not invariant across versions, this
        # is an explicit equivalence check.
        if [[ ${v1[$i]} -ne ${v2[$i]} ]]; then
            echo "Warning: format-code prefers clang-format version $1, installed version is $2"
        fi
    done
}

##==============================================================================
##
## Check for installed clang-format tool
##
##==============================================================================
check_clang-format()
{
    # First check explicitly for the clang-format-7 executable.
    cf=$(command -v clang-format-7 2> /dev/null)

    if [[ -x ${cf} ]]; then
        cf="clang-format-7"
        return
    else
        cf=$(command -v clang-format 2> /dev/null)
        if [[ ! -x ${cf} ]]; then
            echo "clang-format is not installed"
            exit 1
        fi
        cf="clang-format"
    fi

    local required_cfver='17.0.3'
    # shellcheck disable=SC2155
    local cfver=$(${cf} --version | grep -o -E '[0-9]+\.[0-9]+\.[0-9]+' | head -1)
    check_version "${required_cfver}" "${cfver}"
}

check_clang-format

##==============================================================================
##
## Determine parameters for finding files to format
##
##==============================================================================

findargs='find .'

get_find_args()
{
    local defaultExcludeDirs='./.git ./external ./packages ./x64'
    local defaultIncludeExts='h hpp c cpp idl acf'

    if [[ -z ${userExcludeDirs} ]]; then
        read -r -a excludeDirs <<< "${defaultExcludeDirs}"
    else
        log_verbose "Using user directory exclusions: ${userExcludeDirs}"
        read -r -a excludeDirs <<< "${userExcludeDirs}"
    fi

    for exc in "${excludeDirs[@]}"
    do
        findargs="${findargs} ! \( -path '${exc}' -prune \)"
    done

    if [[ -z ${userIncludeExts} ]]; then
        # not local as this is used in get_file_list() too
        read -r -a includeExts <<< "${defaultIncludeExts}"
    else
        log_verbose "Using user extension inclusions: ${userIncludeExts}"
        read -r -a includeExts <<< "${userIncludeExts}"
    fi

    findargs="${findargs} \("
    for ((i=0; i<${#includeExts[@]}; i++));
    do
        findargs="${findargs} -iname '*.${includeExts[$i]}'"
        if [[ $((i + 1)) -lt ${#includeExts[@]} ]]; then
            findargs="${findargs} -o"
        fi
    done
    findargs="${findargs} \)"
}

get_find_args

log_verbose "Query for files for format:"
log_verbose "${findargs}"
log_verbose ""

##==============================================================================
##
## Call clang-format for each file to be formatted
##
##==============================================================================

filecount=0
changecount=0

cfargs="${cf} -style=file"
if [[ ${whatif} -ne 1 ]]; then
    cfargs="${cfargs} -i"
fi

get_file_list()
{
    if [[ -z "${userFiles[*]}" ]]; then
        mapfile -t file_list < <(eval "$findargs")
        if [[ ${#file_list[@]} -eq 0 ]]; then
            echo "No files were found to format!"
            exit 1
        fi
    else
        log_verbose "Using user files: ${userFiles[*]}"
        file_list=()
        for file in "${userFiles[@]}"; do
            for ext in "${includeExts[@]}"; do
                if [[ ${file##*\.} == "$ext" ]]; then
                    file_list+=( "$file" )
                    log_verbose "Checking user file: ${file}"
                    break
                fi
            done
        done
    fi
}

get_file_list

for file in "${file_list[@]}"
do
    ((filecount+=1))
    cf="${cfargs} $file"

    log_whatif "Formatting $file ..."

    if [[ ${whatif} -eq 1 ]]; then
        ${cf} | diff -u "$file" -
    else
        if [[ ${verbose} -eq 1 ]]; then
            ${cf}
        else
            ${cf} > /dev/null
        fi
    fi

    #shellcheck disable=SC2181
    if [[ $? -ne 0 ]]; then
        if [[ ${whatif} -eq 1 ]]; then
            ((changecount+=1))
        else
            echo "clang-format failed on file: $file."
        fi
    fi
done

log_whatif "${filecount} files processed, ${changecount} changed."

# If files are being edited, this count is zero so we exit with success.
exit "$changecount"