#!/usr/bin/env bash

if [[ "$BASH_VERSION" =~ ^3 ]] {
    echo 'quinedb requires bash 4!'
    exit 1
}

declare -A db

setvar db = ''(
)

setvar PREAMBLE = $(cat <<'EOF'
#!/usr/bin/env bash

if [[ "$BASH_VERSION" =~ ^3 ]]; then
    echo 'quinedb requires bash 4!'
    exit 1
fi

declare -A db
EOF
)

setvar POSTAMBLE = $(cat <<'EOF'
pr_str () {
    printf "%q" "$1"
}

case "$1" in
    "get")
        if [ ${db["$2"]+_} ]; then
            v=${db["$2"]}
            echo "$(pr_str "$v")" >&2
        fi
    ;;
    "set")
        db["$2"]="$3"
        echo 'OK' >&2
    ;;
    "delete")
        unset db["$2"]
        echo 'OK' >&2
    ;;
    "keys")
        for k in "${!db[@]}"; do echo "$(pr_str "$k")"; done >&2
    ;;
    *)
        echo "USAGE: quinedb [get k | set k v | delete k | keys]" >&2
    ;;
esac

# print self

print_db(){
    echo "db=("
    i=0
    for k in "${!db[@]}"; do
        escaped_keys[$i]=$(pr_str "$k")
        i=$((i+1))
    done

    # sort the keys for deterministic printing
    IFS=$'\n' sorted=($(for l in ${escaped_keys[@]}; do echo $l; done | sort))
    unset IFS

    for k in "${sorted[@]}"; do
        unescaped=$(eval "echo $k")
        v=${db["$unescaped"]}
        echo "    [$k]=$(pr_str "$v")"
    done
    echo ")"
}

echo "$PREAMBLE"; echo
print_db; echo
echo 'PREAMBLE=$(cat <<'\'EOF\'
echo "$PREAMBLE"
echo EOF
echo \); echo
echo 'POSTAMBLE=$(cat <<'\'EOF\'
echo "$POSTAMBLE"
echo EOF
echo \); echo
echo "$POSTAMBLE"
EOF
)

proc pr_str {
    printf "%q" $1
}

case (1) {
    "get" {
        if test ${db["$2"]+_} {
            setvar v = ${db["$2"]}
            echo $(pr_str "$v") >&2
        }
    }
    "set" {
        setvar db["$2"]="$3"
        echo 'OK' >&2
    }
    "delete" {
        unset db["$2"]
        echo 'OK' >&2
    }
    "keys" {
        for k in "${!db[@]}" { echo $(pr_str "$k"); } >&2
    }
    * {
        echo "USAGE: quinedb [get k | set k v | delete k | keys]" >&2
    }
}

# print self

proc print_db {
    echo "db=("
    setvar i = '0'
    for k in "${!db[@]}" {
        setvar escaped_keys[$i]=$(pr_str "$k")
        setvar i = $((i+1))
    }

    # sort the keys for deterministic printing
    setvar IFS = '$'\n',' sorted = ''($(for l in ${escaped_keys[@]}; do echo $l; done | sort))
    unset IFS

    for k in "${sorted[@]}" {
        setvar unescaped = $(eval "echo $k")
        setvar v = ${db["$unescaped"]}
        echo "    [$k]=$(pr_str "$v")"
    }
    echo ")"
}

echo $PREAMBLE; echo
print_db; echo
echo 'PREAMBLE=$(cat <<''''EOF'''
echo $PREAMBLE
echo EOF
echo ')'; echo
echo 'POSTAMBLE=$(cat <<''''EOF'''
echo $POSTAMBLE
echo EOF
echo ')'; echo
echo $POSTAMBLE