#!/bin/sh

set -e

REPOSITORY=https://github.com/descartes-underwriting/devops-technical-test-data.git
BRANCH=main
DATA_DIR=$(pwd)/data
MAX_NUM=0
VERBOSE=0

while getopts ":r:b:d:vxn:" opt
do
    case ${opt} in
        r)
            REPOSITORY=${OPTARG}
            ;;
        b)
            BRANCH=${OPTARG}
            ;;
        d)
            DATA_DIR=${OPTARG}
            ;;
        n)
            MAX_NUM=${OPTARG}
            ;;
        v)
            VERBOSE=1
            ;;
        x)
            set -x
            ;;
        ?)
            echo "Invalid option -${OPTARG}"
            exit 1
            ;;
    esac
done

IFS="
"

GIT=git
GIT_OPTS=(-c core.quotepath=false)

if test ! -d ${DATA_DIR}
then
    mkdir -p ${DATA_DIR}
fi

TMPDIR=$(mktemp -d)
cd ${TMPDIR}

git clone ${REPOSITORY} && cd ./*

# List all commit sha, from older to newer; 
COMMIT_SHAS=$($GIT ${GIT_OPTS[@]} log --reverse --pretty=format:"%H" remotes/origin/${BRANCH})

NUM_ADDED=0

for COMMIT_SHA in ${COMMIT_SHAS}
do
    if test -d ${DATA_DIR}/${COMMIT_SHA}
    then
        # commit already backup; skipping
        continue
    fi

    echo "new commit: ${COMMIT_SHA}"

    # There are malformed files names that are creating complex filenames to parse.
    # Those malformed filenames are double quotes, so to remove quotes, -c core.quotepath=false
    # and -z are used. sed 's/\x0//g' is removing the null byte
    FILES=$($GIT ${GIT_OPTS[@]} show --pretty= --name-only -z ${COMMIT_SHA} | sed 's/\x0//g')

    if test -z ${FILES}
    then
        # merge commit, etc. There is no file here.
        echo "No file was found in commit ${COMMIT_SHA}"
    fi

    TARGET_BACKUP_SHA=${DATA_DIR}/${COMMIT_SHA}
    mkdir -p ${TARGET_BACKUP_SHA}

    for FILE in ${FILES}
    do
        TARGET_DIR=$(dirname ${FILE})
        mkdir -p ${TARGET_BACKUP_SHA}/${TARGET_DIR}

        if test ${VERBOSE} -eq 1
        then
            echo "Writing ${TARGET_BACKUP_SHA}/${FILE}"
        fi

        # Retrieve file state (Added, Modified, Deleted)
        STATE=$(${GIT} ${GIT_OPTS[@]} show --name-status --pretty= ${COMMIT_SHA} | grep -E '^..${FILE}$' | cut -f1)

        if test "${STATE}" != "D"
        then
            # ${FILE} contains path/to/file
            $GIT ${GIT_OPTS[@]} show ${COMMIT_SHA}:${FILE} > ${TARGET_BACKUP_SHA}/${FILE}
        else
            echo "Skipping ${FILE} as file was deleted in this commit"
        fi
    done

    # if ${TARGET_BACKUP_SHA} is empty, keep track it was "backuped"
    if test -z "$(ls -A ${TARGET_BACKUP_SHA})"
    then
        echo "Folder ${TARGET_BACKUP_SHA} is empty. Marking it to keep as it in the backup"
        touch ${TARGET_BACKUP_SHA}/.gitkeep
    fi

    NUM_ADDED=$((NUM_ADDED + 1))

    if test ${NUM_ADDED} -eq ${MAX_NUM}
    then
        echo "Max commit to backup reached; stopping."
        break
    fi
done

echo "done: ${NUM_ADDED}"