#!/usr/bin/env bash

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

declare -A db

setglobal db = ''(
)

setglobal PREAMBLE = $[cat << '''
#!/usr/bin/env bash

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

declare -A db
'''
]

setglobal POSTAMBLE = $[cat << '''
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"
'''
]

proc pr_str {
    printf "%q" $1
}

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

# print self

proc print_db{
    echo "db=("
    setglobal i = '0'
    for k in [$(!db[@])] {
        compat array-assign escaped_keys '$i' $[pr_str $k]
        setglobal i = $shExpr('i+1')
    }

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

    for k in [$(sorted[@])] {
        setglobal unescaped = $[eval "echo $k]
        setglobal 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