#!/bin/bash

# doc cmd_update{
#
# DESCRIPTION
#   cmd_update - Updates database of TARGET from git HEAD to last commit hash.
#
# USAGE
#   cmd_update </path/to/git/dir> </path/to/target/dir>
#
# }

cmd_update() {
    local GIT_DIR="${1}"
    local TARGET="${2}"
    local DB_FILE="${TARGET}/${_OPT_DB_FILE}"

    # In the event that LAST_COMMIT OR DB_FILE does not exist, echo out that the LAST_COMMIT 
    # is the first COMMIT of GIT_DIR, thus stating that no database update has ever occured
    if [[ -z "$(grep LAST_UPDATE ${DB_FILE})" ]]; then
        echo -e "LAST_UPDATE\t$(git -C "${GIT_DIR}" rev-list HEAD | tail -n 1)" >> ${DB_FILE}
    fi

    # Defines what imageids needs updating by determining what files has changed since last
    # update via git diff --name-only.
    local NEW_COMMIT=$(git -C "${GIT_DIR}" rev-parse HEAD)
    local OLD_COMMIT=$(awk 'BEGIN{FS="\t"}{if($1=="LAST_UPDATE"){print $2}}' ${DB_FILE})
    local imageidList=($(sed 's/\(.*\)\..*/\1/' <<< $(git -C "${GIT_DIR}" diff --name-only ${NEW_COMMIT} ${OLD_COMMIT}) | awk '!seen[$0]++' | grep SHA256))
    
    _msg EXEC "Updating database from ${OLD_COMMIT} to ${NEW_COMMIT}" 
    db_update "${GIT_DIR}" "${TARGET}" "${DB_FILE}" ${imageidList[@]}
    [[ $? -ne 0 ]] && { _msg WARN; local ERR=true; } || _msg OK
    [[ ${ERR} ]] && return 1 || { gawk -i inplace -v newcommit=${NEW_COMMIT} 'BEGIN{FS="\t";OFS="\t"}{if($1=="LAST_UPDATE"){$2=newcommit}{print $0}}' ${DB_FILE}; return 0; }
}