#!/bin/bash

shellfu import exit
shellfu import inigrep
shellfu import pretty

#
# Path where saturnin__conf should look for files
#
# If filename does not contain slash, it is looked up in each
# (or all, based on strategy--see saturnin__conf() doc) path in this
# list.  The list is colon-separated and non-dirs as well as
# empty strings are silently ignored.
#
SATURNIN_CONF_PATH="${SATURNIN_CONF_PATH:-}"

#
# Expected config filename extension (for guessing from path head)
#
# If no filename to read is given, saturnin__conf() will guess
# filename as the path head plus this suffix (e.g. `foo.ini` for
# `saturnin__conf foo.bar.baz`)
#
SATURNIN_CONF_SUFFIX="${SATURNIN_CONF_SUFFIX:-.ini}"

saturnin__conf() {
    #
    # inigrep smart loader
    #
    # Usage:
    #   saturnin__conf [-j] [inigrep-query] [-- [file]..]
    #
    #
    # File arguments
    # ==============
    #
    # If omitted, *file* argument is inferred by taking part of
    # kpath name before first dot and appending value of
    # `$SATURNIN_CONF_SUFFIX`, (".ini" by default).
    #
    # Each *file* argument is then processed as follows:
    #
    #  *  `-` (single dash) is interpreted as reading from
    #     STDIN.
    #
    #  *  If argument contains slash, it is expanded as a regular
    #     path (relative or absolute).
    #
    #  *  Otherwise, it is taken as filename and searched for
    #     in directories given in `$SATURNIN_CONF_PATH`.  (This can
    #     yield more than one path, which is equivalent as if
    #     all paths were provided.)
    #
    #     Not all files expanded based on `$SATURNIN_CONF_PATH`
    #     are read by default; reading is governed by "merge
    #     strategy": the default strategy "first" reads only
    #     the first existing file.
    #
    #     "join" strategy on the other hand, means that any
    #     files are simply concatenated and prefixed with
    #     comment (visible only in raw mode) containing path
    #     to the file.
    #
    #     This means that if a section is queried that is
    #     present in both files, it is effectively concatenated
    #     as well.
    #
    # Following calls are equivalent
    #
    #     saturnin__conf foo.bar.baz
    #     saturnin__conf foo.bar.baz foo.ini
    #
    # and both result in reading of key *baz* from section *foo.bar*
    # in file *foo.ini*, which is selected from *SATURNIN_CONF_PATH*.
    # Should there be more foo.ini's, the first is selected.
    # Using `-j` switch
    #
    #     saturnin__conf -j foo.bar.baz
    #
    # would cause all foo.ini's on *SATURNIN_CONF_PATH* be
    # concatenated instead.
    #
    local ig_mode               # retrieval mode
    local ig_query              # keypath or section name (when listing keys)
    local ig_limit              # line limit
    local files=()              # file specification
    local Strategy=first        # merge strategy
    while true; do case $1:$2 in
        "":*)   break ;;
        -j:*)   Strategy=join;           shift 1        ;;
        -1:*)   ig_limit=$1;             shift 1        ;;
        -e:*.*) ig_mode=$1; ig_query=$2; shift 2; break ;;
        -r:*.*) ig_mode=$1; ig_query=$2; shift 2; break ;;
        -K:*)   ig_mode=$1; ig_query=$2; shift 2; break ;;
        -S:*)   ig_mode=$1; ig_query=""; shift 1; break ;;
        -P:*)   ig_mode=$1; ig_query=""; shift 1; break ;;
        .*:*)   warn "bad syntax: $*"; _saturnin__conf_usage ;;
        *.*:*)  ig_mode=-e; ig_query=$1; shift 1; break ;;
        --help:*) _saturnin__conf_usage -e 0                 ;;
        *)      warn "bad syntax: $*"; _saturnin__conf_usage ;;
    esac done
    test -n "$ig_mode" || { warn "could not determine inigrep mode"; _saturnin__conf_usage; }
    debug -v ig_limit ig_query ig_mode Strategy
    if test -n "$*";
    then
        files=("$@")
    elif test -n "$ig_query";
    then
        files=("${ig_query%%.*}$SATURNIN_CONF_SUFFIX")
    else
        warn "dunno what to load"
        _saturnin__conf_usage
    fi
    debug -v files
    #shellcheck disable=SC2086
    _saturnin__conf__load "${files[@]}" | inigrep $ig_limit $ig_mode "$ig_query"
    return "${PIPESTATUS[0]}"
}

saturnin__get() {
    #
    # Show Saturnin Internal info by key $1 and exit
    #
    # Key $1 can be whole `--saturnin-get-stuff` argument or just
    # the part after `--saturnin-get-`.
    #
    # This is aimed to help debugging and testing the app (or
    # Saturnin itself) by showing packaging and deployment related
    # info.
    #
    local key=${1#--saturnin-get-}
    case "$key" in
        shellfu-path)   echo "$SHELLFU_PATH"                ;;
        saturnin-conf-path) echo "$SATURNIN_CONF_PATH"      ;;
        app-git-hash)   echo "$SATURNIN_APP_GIT_HASH"       ;;
        app-version)    echo "$SATURNIN_APP_VERSION"        ;;
        cache-home)     echo "$SATURNIN_CACHE_HOME"         ;;
        libexec)        echo "$SATURNIN_LIBEXEC"            ;;
        libexec-prefix) echo "$SATURNIN_LIBEXEC_PREFIX"     ;;
        *)              warn "unknown devel key: $key"
                        exit "$EXIT_USAGE" ;;
    esac
    exit "$EXIT_OK"
}

saturnin__lssc() {
    #
    # List subcommands
    #
    echo conf
    find "$SATURNIN_LIBEXEC" \
        -mindepth 1 \
        -maxdepth 1 \
        -executable \
      | sed -e "s|^.*/||; s|^$SATURNIN_LIBEXEC_PREFIX||" \
      | sort
}

saturnin__main() {
    local subcommand
    while true; do case $1 in
        -d|--debug)     export PRETTY_DEBUG=true;   shift ;;
        -v|--verbose)   export PRETTY_VERBOSE=true; shift ;;
        -h|--help)      saturnin__usage -e 0;       exit  ;;
        --version)      saturnin__version;          exit  ;;
        --version-semver) saturnin__get app-version ;;
        --saturnin-get-*) saturnin__get "$1"        ;;
        -*)             saturnin__usage;            ;;
        --*)            saturnin__usage;            ;;
        --)             shift; break                ;;
        "")             saturnin__usage;            ;;
        *)              break;                      ;;
    esac done
    subcommand="$1"; shift
    debug -v SHELLFU_PATH SATURNIN_LIBEXEC SATURNIN_CONF_PATH
    case "$subcommand" in
        conf)    saturnin__conf "$@"                ;;
        _ls_sc)  saturnin__lssc                     ;;
        _lsfun)  shellfu-get lsfun                  ;;
        _lsmod)  shellfu-get lsmod                  ;;
        *)       saturnin__runsc "$subcommand" "$@" ;;
    esac
}

saturnin__conf_mkpath() {
    #
    # Assemble SATURNIN_CONF_PATH from locations $@
    #
    # For each location, print colon-delimited list of
    # directories.  If location ends with "/ini.d", list of
    # subfolders, sorted by C locale is printed--this allows
    # for modular configuration.  Otherwise the location
    # is printed.  Non-existent or non-directory locations
    # are silently ignored.
    #
    local location      # one location argument
    local path          # one path listed
    for location in "$@";
    do
        test -d "$location" || continue
        case "$location" in
            */ini.d)    # modular location--sort subfolders
                find -L "$location" -mindepth 1 -maxdepth 1 -type d \
                  | LC_ALL=C sort
                ;;
            *)
                echo "$location"
                ;;
        esac
    done \
      | _saturnin__nl2colon
}

saturnin__runhook() {
    #
    # Run custom hook
    #
    local hname="$1"
    local hook_code
    test -n "$SATURNIN_SUBCOMMAND" || {
        warn "unknown subcommand, ignoring hook: $hname"
        return 0
    }
    hook_code="$(saturnin__conf -j "hook.$SATURNIN_SUBCOMMAND.$hname")"
    debug -v SATURNIN_SUBCOMMAND hook_code hname
    bash -n <<<"$hook_code" || {
        warn "syntax errors, ignoring hook: $hname"
        return 0
    }
    eval "$hook_code"
}

saturnin__runsc() {
    #
    # Run subcommand $SATURNIN_SUBCOMMAND
    #
    local subcommand="$1"; shift
    local binpath   # path to subcommand's binary
    binpath+="$SATURNIN_LIBEXEC/"
    binpath+="$SATURNIN_LIBEXEC_PREFIX$subcommand"
    debug -v binpath
    debug "\$*='$*'"
    test -x "$binpath" || {
        warn "invalid sub-command: $subcommand"
        saturnin__usage
    }
    SATURNIN_SUBCOMMAND="$subcommand" "$binpath" "$@"
}

saturnin__usage() {
    #
    # Show usage message and exit
    #
    #shellcheck disable=SC2046
    mkusage "$@"                                            \
            "[options] COMMAND [ARG...]"                    \
        -o                                                  \
            "-d, --debug    turn on debugging"              \
            "-h, --help     show this help message and exit"\
            "-v, --verbose  turn on verbosity"              \
            "--version      show version and exit"          \
        -c                                                  \
            $(saturnin__lssc)
}

saturnin__version() {
    #
    # Print version info
    #
    local tagline=${SATURNIN_APP_TAGLINE:-Some app with default tagline}
    local maybe_codename=""
    test -n "$SATURNIN_APP_CODENAME" && maybe_codename=" - $SATURNIN_APP_CODENAME"
    echo "$(basename "$0") ($tagline) $SATURNIN_APP_VERSION$maybe_codename"
    return "$EXIT_OK"
}

saturnin__wraphook() {
    #
    # Wrap command "$@" in hooks
    #
    # Run pre hook, then "$@", then post hook.  Always exit
    # with status of "$@", even if hooks fail.  Ignore
    # post-hook if "$@" failed.
    #
    local es=0
    saturnin__runhook pre
    "$@" || return $?
    es=$?
    saturnin__runhook post
    return $es
}


#          #                           that what you see below this line #
# INTERNAL # ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ #
#          #                        use in your code to anger the divine #

_saturnin__conf__merge() {
    #
    # Take paths and applying merge strategy, load file(s)
    #
    local path
    local found=false
    while read -r path;
    do
        test -f "$path" || continue
        found=true
        case $Strategy in
            first)
                debug "winner: $path"
                cat "$path"
                cat >/dev/null  # throw away rest of paths
                ;;
            join)
                echo "# file: ${path/$HOME/~}"
                cat "$path" 2>/dev/null
                ;;
        esac
    done
    $found
}

_saturnin__conf__load() {
    #
    # Print contents of files specified in $@
    #
    # Each argument means possible file candidate.  If candidate
    # contains slash, it's treated as file path and is printed
    # directly.  If it's single dash, standard input is copied.
    #
    # In all other cases, filename is searched in all elements
    # of SATURNIN_CONF_PATH; output then depends on chosen $Strategy:
    # with 'first' strategy, first existing file is printed, with
    # 'join' strategy. all existing files are printed.
    #
    local arg trydir trypath es
    es=0
    for arg in "$@";
    do
        case $arg in
            -|*/*)      # stdin, or path (with slash)
                cat "$arg" || es=3
            ;;
        *)              # name given, find all its incarnations
            debug -v SATURNIN_CONF_PATH
            echos "$SATURNIN_CONF_PATH" \
              | tr ':' '\n' \
              | while read -r trydir;
                do
                    test -n "$trydir" || continue
                    trypath="$trydir/$arg"
                    echos "$trypath"
                done \
              |  _saturnin__conf__merge; es=$?
            ;;
        esac
    done
    return $es
}

_saturnin__conf_usage() {
    #
    # Show usage message and exit
    #
    PRETTY_USAGE="self=${0##*/} conf" \
    mkusage "$@"                                                               \
            "[options] [-e] SECTION.KEY [FNAME]"                               \
            "[options] -r SECTION.KEY [FNAME]"                                 \
            "[options] -K SECTION [FNAME]"                                     \
            "[options] -P FNAME"                                               \
            "[options] -S FNAME"                                               \
        --                                                                     \
            "Use inigrep to query config files."                               \
        -o                                                                     \
            "-j     join all files before applying query"                      \
            "-1     ensure single line is returned"                            \
        -c                                                                     \
            "-e     use normal mode (default)"                                 \
            "-r     use raw mode (preserves RHS whitespace and some comments)" \
            "-K     list available keys in SECTION"                            \
            "-S     list available sections in FNAME"                          \
            "-P     list available keypaths (SECTION.KEY) in FNAME"            \
        --                                                                     \
            "FNAME is filename, which is then searched on all paths specified" \
            "in SATURNIN_CONF_PATH and depending on -j parameter, first one"   \
            "wins or all are joined.  If FNAME contains slash, this search is" \
            "not done and FNAME is taken as path to file that is then queried."\
            ""                                                                 \
            "If FNAME is omitted, it is inferred from SECTION (e.g. .'foo.ini'"\
            "if 'foo.bar' was section name; note that section name may contain"\
            "dot)."
}

_saturnin__nl2colon() {
    #
    # Convert newline-based list of paths to colon:based:list
    #
    # Empty paths must not be included in the resulting list,
    # so we need to drop them and also get the colons right.
    #
    local idx=0     # current item index (zero-based)
    local path
    while read -r path;
    do
        test -z "$path" && continue
        test $idx -gt 0 && echo -n ':'
        echo -n "$path"
        ((idx++))
    done
}