#!/usr/bin/env sh

# POSIX shell implementation of Gitrect
#
# Operate on a tempfile and generate a listing of:
#
# prefix-trim-directory,remote=URL,...
#
# For all directories found in $WORKDIR

# Operate on tempfile
TEMPFILE="/tmp/gitrect.temp.$(xxd -l6 -p /dev/urandom)"
touch $TEMPFILE

# Reset all variables that might be set
DEFAULT_STATE="$HOME/.local/share/git/repolist"
WORKDIR="$HOME/.code"
verbose=0 # Variables to be evaluated as shell arithmetic should be initialized to a default or validated beforehand.
noconfirm=0

if [ ! $(command -v git) ]; then
    echo "git command not found. git must be installed and available in \$PATH to continue"
    exit 1
fi

usage="$(basename "$0") [-h] [-v -w WORKDIR -f FILE]

where:
    -w  set the working directory (default: ${WORKDIR})
    -f  set the git list file (default: ${DEFAULT_STATE})
    -y  yes to all prompts (no confirmation)

    -h  show this help text
    -v  verbose output (multiple flags increase verbosity)
        (ex: '-v -v')
"

while :; do
    case $1 in
        -h | -\? | --help) # Call a "show_help" function to display a synopsis, then exit.
            echo "$usage"
            exit
            ;;
        -f) # Takes an option argument, ensuring it has been specified.
            if [ -n "$2" ]; then
                DEFAULT_STATE=$2
                shift
            fi
            ;;
        -f=?*)
            DEFAULT_STATE=${1#*=} # Delete everything up to "=" and assign the remainder.
            ;;
        -f=) # Handle the case of an empty --file=
            printf 'ERROR: "-f" requires a non-empty option argument.\n' >&2
            exit 1
            ;;
        -w) # Takes an option argument, ensuring it has been specified.
            if [ -n "$2" ]; then
                WORKDIR=$2
                shift
            fi
            ;;
        -w=?*)
            WORKDIR=${1#*=} # Delete everything up to "=" and assign the remainder.
            ;;
        -w=) # Handle the case of an empty --file=
            printf 'ERROR: "-w" requires a non-empty option argument.\n' >&2
            exit 1
            ;;
        -y)
            noconfirm=1
            ;;
        -v)
            verbose=$((verbose + 1)) # Each -v argument adds 1 to verbosity.
            ;;
        --) # End of all options.
            shift
            break
            ;;
        -?*)
            printf 'WARN: Unknown option (ignored): %s\n' "$1" >&2
            ;;
        *) # Default case: If no more options then break out of the loop.
            break ;;
    esac
    shift
done

# Make sure local state folder is available
if [ ! -d "$HOME/.local/share" ]; then
    if [ $verbose -gt 0 ]; then
        echo "Creating directory: $HOME/.local/share"
    fi
    mkdir -p ~/.local/share
fi

# Rest of the program here.
# If there are input files (for example) that follow the options, they
# will remain in the "$@" positional parameters.

if [ "$(command -v fd)" ]; then
    LIST=$(eval "fd -I -H -t d '\.git$' ${WORKDIR}")
else
    LIST=$(eval "find -type d -name \.git ${WORKDIR}")
fi

# for each directory, create a line in TEMPFILE equivalent to:
# short/path/here,origin=url1,upstream=url2,...
#
for dirpath in $LIST; do
    # shortpath trims the working directory prefix and the '.git' suffix from the directory
    shortpath=$(eval "echo $dirpath | sed -e 's,${WORKDIR}/,,' -e 's,/\.git/,,'")
    if [ $verbose -gt 1 ]; then
        echo "Repository found: ${shortpath}" >&2
    fi

    cd "${dirpath}/.."        # change into the parent of the git directory
    rems=$(eval "git remote") # list all remotes
    len_rems=${#rems}
    if [ $len_rems -lt 1 ]; then
        # If the list of remotes is zero, skip this folder
        continue
    fi

    # We haven't skipped the path, so write it to the file
    printf "%s" $shortpath >>$TEMPFILE
    for r in $rems; do
        url=$(eval "git remote get-url ${r}")
        printf ",%s=%s" $r $url >>$TEMPFILE
        if [ $verbose -gt 1 ]; then
            echo "remote: ${r} ${url} " >&2
        fi
    done
    printf "\n" >>$TEMPFILE
done

# Sort results
sort -o ${TEMPFILE} ${TEMPFILE}

diffval=$(eval "diff -b ${DEFAULT_STATE} ${TEMPFILE}")
if [ $? -eq 0 ]; then
    if [ $verbose -gt 0 ]; then
        echo "No change. Configuration already up to date." >&2
    fi
    # Cleanup temp file
    rm "${TEMPFILE}"
else
    if [ $verbose -gt 0 ]; then
        echo "Diff between current and updated state: " >&2
        echo "$diffval" >&2
    fi
    if [ $noconfirm -ne 0 ]; then
        # Overwite origiaal with the new
        mv "${TEMPFILE}" "${DEFAULT_STATE}"
    else
        printf 'Accept changes (y/n)? \n'
        old_stty_cfg=$(stty -g)
        stty raw -echo
        answer=$(while ! head -c 1 | grep -i '[ny]'; do true; done)
        stty $old_stty_cfg
        if [ "$answer" != "${answer#[Yy]}" ]; then
            echo "Updating file..."
            # Overwite origiaal with the new
            mv "${TEMPFILE}" "${DEFAULT_STATE}"
        else
            echo "Discarding changes..."
            rm "${TEMPFILE}"
        fi
    fi
fi