#!/usr/bin/env bash

# copyright/Open GoPro, Version 2.0 (C) Copyright 2021 GoPro, Inc. (http://gopro.com/OpenGoPro).
# This copyright was auto-generated on Wed, Sep  1, 2021  5:06:27 PM

COPYRIGHT="##FILE##/Open GoPro, Version ##VERSION## (C) Copyright 2021 GoPro, Inc. (http://gopro.com/OpenGoPro)."
TIME="This copyright was auto-generated on ##TIME##"

INPUT=
CHECK_ONLY=false

num_wrong=0

help() {
    cat <<EOF

Usage: copyright [OPTIONS] VERSION
Check for or apply copyrights to source files.

Required positional arguments:
    VERSION          version to check for / apply in the copyright

Optional arguments:
    -i INPUT         INPUT is directory to analyze. By default if not passed, git changed / added files will be analyzed.
    -h               Print this Help.
    -c               Check only (and output problems). Do not apply changes. Returns 3 if any missing copyrights found

EOF
}

# MacOS doesn't have realpath. This is taken from https://stackoverflow.com/questions/3572030/bash-script-absolute-path-with-os-x
realpath_support_macos() {
    [[ $1 = /* ]] && echo "$1" || echo "$PWD/${1#./}"
}

main() {
    # Build array of input files
    IFS=$'\n' # Change interframe separator to handle files with spaces
    if [ -z "$INPUT" ]; then
        echo "Analyzing added / modified files."
        files=($(git diff --cached --name-only --diff-filter=ACM)) # Added / modified files
    else
        echo "Analyzing all files recursively at $(realpath_support_macos $INPUT)."
        # All files except for those in .git and
        # Lunr files which must contain front matter at first line
        files=($(find $INPUT -type f ! -path "./.git/*" ! -path "./docs/assets/js/lunr/*"))
    fi

    # Ensure there are any files to analyze
    if [[ "${#files[@]}" == 0 ]]; then
        echo "No files to analyze."
        exit 0
    fi

    FORMAT="%-120s | %-7s | %-7s | %-7s | %-7s |"
    printf "\n$FORMAT\n" "FILE" "CORRECT" "WRONG" "MISSING" "N/A"
    printf '=%.0s' {1..162}
    echo

    # Analyze each file for a copyright
    for file in ${files[@]}; do
        copyright=
        line_start=
        line_end=
        found_version=
        incorrect="MISSING"

        # Is there a copyright?
        # Note! We're only looking at the first 7 lines as an optimization to avoid reading large files.
        # In actuality, there is no reason for it be after the 3rd line.
        copyright=$(head -n 7 $file | cat -n | grep -m1 '(C) Copyright.*GoPro' | sed -e 's/^[[:space:]]*//') # Add line numbers when cat'ing, then trim leading whitespace.
        generic_copyright=$(head -n 7 $file | cat -n | grep -i -m1 'copyright' | sed -e 's/^[[:space:]]*//')
        if [[ "$copyright" ]]; then
            # If this file explicitely does not get a copyright, continue
            if  [[ $(echo "$copyright" | grep -c "No (C) Copyright") > 0 ]]; then
                printf "$FORMAT\n" "$file" "" "" "" "*"
                continue
            fi
            # Is this the correct version, continue
            found_version=$(echo "$copyright" | sed 's/.*Version \(.*\) (C).*/\1/')
            if [[ "$VERSION" == "$found_version" ]]; then
                printf "$FORMAT\n" "$file" "*"
                continue
            fi
            # The version is incorrect. If we are to make changes (i.e. we are not only checking)...
            incorrect="WRONG_VERSION"
            if [[ "$CHECK_ONLY" == false ]]; then
                # Get line number where copyright starts
                line_start=$(echo "$copyright" | cut -f1)
                # And where it ends (line 1 = copyright, line 2 = timestamp, line 3 = newline)
                line_end=$((line_start + 2))
                # Strip the lines since we will add the correct copyright below
                lines="$line_start,$line_end"
                sed -i.bak "$lines"'d' $file && rm "$file".bak # The .bak is to appease MacOS
            fi
        elif [[ "$generic_copyright" ]]; then
            #this file has a copyright that is potentially not our own
            printf "$FORMAT\n" "$file" "" "" "" "*"
            continue
        fi

        # The copyright was either missing or had an incorrect version. Now see if this file deserves a copyright.
        # First check known filenames that don't have extensions
        case $(basename "$file") in
        Makefile | Dockerfile)
            start="#"
            stop=""
            ;;
        *)
            # Now check file extensions
            extension="${file##*.}"
            case $extension in
            py | yml | r | R | rb)
                start="#"
                stop=""
                ;;
            c | h | cpp | cxx | hpp | js | ts | swift | css | proto | java | cs | kt | kts | ktm | m | php | rs | go | dart)
                start="/*"
                stop=" */"
                ;;
            lua)
                start="--"
                stop=""
                ;;
            *)
                # Special case for shell files. We use the file command since they might not have an extension
                if [[ $(echo $(file $file) | grep -c "shell script") > 0 ]]; then
                    start="#"
                    stop=""
                else
                    printf "$FORMAT\n" "$file" "" "" "" "*"
                    continue
                fi
                ;;
            esac
            ;;
        esac

        num_wrong=$((num_wrong + 1))
        if [[ "$incorrect" == "MISSING" ]]; then
            printf "$FORMAT" "$file" "" "" "X"
        else
            printf "$FORMAT" "$file" "" "X"
        fi

        # Build the copyright string if desired
        if [[ "$CHECK_ONLY" == false ]]; then
            # Replace template strings with actual values and make into comment
            new_copyright="${COPYRIGHT/"##FILE##"/$(basename "$file")}"
            new_copyright="${new_copyright/"##VERSION##"/$VERSION}"
            new_copyright="$start $new_copyright$stop"
            # Build the time string
            time="${TIME/"##TIME##"/$(date)}"
            time="$start $time$stop"

            # Now write it. First we need to find where to put the copyright if there was not already one.
            if [ -z "$line_start" ]; then
                # If shebang exists, write on the line after the shebang. Shebang is always on the first line.
                if [ "$(head -c 2 $file)" = "#!" ]; then
                    line_start=2
                # Otherwise, use the first line
                else
                    line_start=1
                fi
            fi

            # Now build the new file
            head -n $((line_start - 1)) $file >temp 2>/dev/null # Original file up until the line where the copyright was (or is to be)
            # MacOS warns about 0 so pipe sdterr to null
            echo "$new_copyright" >>temp      # Add copyright
            echo "$time" >>temp               # Add timestamp
            echo >>temp                       # Add new line
            tail -n +$line_start $file >>temp # Lines after where the copyright was (or will be)
            mv temp "$file"                   # Replace the original file
            echo " --> Added copyright ✔️"
        else
            echo
        fi
    done

    if [[ "$CHECK_ONLY" == true ]]; then
        echo
        echo "Total found $num_wrong missing or incorrect copyrights"
        if [[ "$num_wrong" > 0 ]]; then
            exit 3
        fi
    fi

    exit 0
}

# Parse optional arguments
while getopts "hci:" option; do
    case ${option} in
    h) #For option h
        help
        exit 0
        ;;
    c) #For option c
        CHECK_ONLY=true
        ;;
    i) #For option i
        INPUT=$OPTARG
        ;;
    \? | :)
        help
        exit 1
        ;;
    *)
        echo "Unexpected error occurred." >&2
        help
        exit 1
        ;;
    esac
done

# Jump to positional arguments
shift $((OPTIND - 1))
if [[ $# < 1 ]]; then
    echo "Missing VERSION parameter" >&2
    help
    exit 1
fi

VERSION=$1

main