#!/bin/bash

#  Includes
. $(miniade) || { echo "${0##*/}: ERROR: miniade failed (hint: run 'miniade' to see error)" >&2; exit 1; }

#  Configurable stuff
#DBFILE=/tmp/$PROGNAME.sqlite

#  Other globals
LOTS_OF_EQUALS="=============================================================================================================================================="

main()
{
    local MY_ARGS
    local PROGNAME

    #  Defaults for options
    DESIRED_MODES=()

    #  Process options
    special_opts_handler()
    {
        case $1 in
            --scan)         DESIRED_MODES=( "${DESIRED_MODES[@]}" scan ) ;;
            --compare)      DESIRED_MODES=( "${DESIRED_MODES[@]}" compare ) ;;
            --freeze)       DESIRED_MODES=( "${DESIRED_MODES[@]}" freeze ) ;;
            --list)         DESIRED_MODES=( "${DESIRED_MODES[@]}" list ) ;;
            --progname=*)   miniade_set_progname ${1#*=} ;;
            *)              return 1 ;;
        esac
    }
    miniade_process_options --special-opts-handler=special_opts_handler --help-handler=help MY_ARGS "$@" && set -- "${MY_ARGS[@]}"

    #  Process arguments (delegated)

    #  Sanity checks and derivations
    miniade_get_progname PROGNAME
    [ ${#DESIRED_MODES[*]} -gt 0 ] || miniade_bad_usage
    if [ -w / ]; then
        STATE_DIR=/var/local/$PROGNAME
    else
        STATE_DIR=$HOME/.cache/$PROGNAME
    fi

    #  Guts (delegate)
    for MODE in scan compare freeze list; do
        if wordin $MODE "${DESIRED_MODES[@]}"; then
            $MODE "$@"
        fi
    done
}

wordin()
{
    local FIRSTWORD NEXTWORD FOUND

    FIRSTWORD=$1
    shift

    FOUND=false
    for NEXTWORD in "$@"; do
        [ "X$NEXTWORD" != "X$FIRSTWORD" ] || { FOUND=true; break; }
    done

    $FOUND
}

scan()
{
    local ROOT_DIR FROZEN_FILE SCANNED_FILE PROGNAME

    #  Process arguments 
    [ $# = 1 ] || miniade_bad_usage
    ROOT_DIR=$1

    #  Sanity checks and derivations
    [[ $ROOT_DIR =~ ^/ ]] || miniade_error "$ROOT_DIR: not absolute"
    ( cd $ROOT_DIR 2>/dev/null ) || miniade_error "$ROOT_DIR: can't access"
    FROZEN_FILE=$STATE_DIR/$(zencode <<<"$ROOT_DIR")-frozen.md5sum
    SCANNED_FILE=$STATE_DIR/$(zencode <<<"$ROOT_DIR")-scanned.md5sum
    miniade_get_progname PROGNAME

    #  Guts
    miniade_lock /tmp/$PROGNAME.lock || miniade_error "locked"
    mkdir -p $STATE_DIR
    miniade_debug 10 "scan: running find ..."
    #  Alphabetical order scan (easier to read by me while being written by script).
    find $ROOT_DIR -type f -print0 | sort -z | xargs -r0 md5sum > $SCANNED_FILE.$$ || true
    miniade_debug 10 "scan: moving result to $SCANNED_FILE ..."
    mv $SCANNED_FILE.$$ $SCANNED_FILE
    miniade_unlock /tmp/$PROGNAME.lock
}

zencode()
{
    sed -e 's/Z/Z5a/g' -e 's/\//Z2f/g'
}

zdecode()
{
    sed -e 's/Z2f/\//g' -e 's/Z5a/Z/g' 
}

list()
{
    local ROOT_DIR FROZEN_FILE SCANNED_FILE ROOT_DIRS

    #  Process arguments 
    [ $# = 0 ] || miniade_bad_usage

    #  Sanity checks and derivations

    #  Guts
    mkdir -p $STATE_DIR
    ROOT_DIRS=( $(ls $STATE_DIR | sed -r 's/-(scanned|frozen)\.md5sum$//' | sort -u | zdecode) )

    for ROOT_DIR in "${ROOT_DIRS[@]}"; do
        FROZEN_FILE=$STATE_DIR/$(zencode <<<"$ROOT_DIR")-frozen.md5sum
        SCANNED_FILE=$STATE_DIR/$(zencode <<<"$ROOT_DIR")-scanned.md5sum
        if [ -f $SCANNED_FILE ] && [ -f $FROZEN_FILE ]; then
            COMMENT="frozen based on a scan that completed at $(stat -c %y $FROZEN_FILE)"
        elif [ -f $SCANNED_FILE ] && [ ! -f $FROZEN_FILE ]; then
            COMMENT="not frozen but scan completed at $(stat -c %y $SCANNED_FILE)"
        elif [ ! -f $SCANNED_FILE ] && [ -f $FROZEN_FILE ]; then
            COMMENT="frozen based on a scan that completed at $(stat -c %y $FROZEN_FILE)"
        elif [ ! -f $SCANNED_FILE ] && [ ! -f $FROZEN_FILE ]; then
            COMMENT="odd state!"
        fi
        printf "%-40s %s\\n" "$ROOT_DIR:" "$COMMENT"
    done
}

compare()
{
    local ROOT_DIR FROZEN_FILE SCANNED_FILE PROGNAME

    #  Process arguments 
    [ $# = 1 ] || miniade_bad_usage
    ROOT_DIR=$1

    #  Sanity checks and derivations
    [[ $ROOT_DIR =~ ^/ ]] || miniade_error "$ROOT_DIR: not absolute"
    FROZEN_FILE=$STATE_DIR/$(zencode <<<"$ROOT_DIR")-frozen.md5sum
    SCANNED_FILE=$STATE_DIR/$(zencode <<<"$ROOT_DIR")-scanned.md5sum
    miniade_get_progname PROGNAME
    [ -f $SCANNED_FILE   ] || miniade_error "no scanned file exists yet (hint: do you need to run '$PROGNAME --scan $ROOT_DIR'?)"
    [ -f $FROZEN_FILE ] || miniade_error "no frozen file exists yet (hint: do you need to run '$PROGNAME --freeze $ROOT_DIR'?)"

    #  Guts
    [ "X$DBFILE" = X ] || rm -f $DBFILE
    {
        echo "CREATE TABLE scanned_files (checksum TEXT, name TEXT, PRIMARY KEY (name));"
        echo "CREATE INDEX scanned_files_checksum_index ON scanned_files(checksum);"
        echo "CREATE INDEX scanned_files_name_index ON scanned_files(name);"
        echo "CREATE TABLE frozen_files (checksum TEXT, name TEXT, PRIMARY KEY (name));"
        echo "CREATE INDEX frozen_files_checksum_index ON frozen_files(checksum);"
        echo "CREATE INDEX frozen_files_name_index ON frozen_files(name);"

        echo "BEGIN TRANSACTION;"
        #  md5sum puts a backslash at the beginning of the line (directly in front of 
        #  the checksum if the filename contains a backslash). Single quotes need to 
        #  escaped, which, in the case of quotes is actually *two* single quotes.
        sed -r -e 's/^\\//' -e "s/'/''/g" -e "s/^([0-9a-f]{32})  (.*)/INSERT INTO scanned_files VALUES ('\\1', '\\2');/" $SCANNED_FILE
        sed -r -e 's/^\\//' -e "s/'/''/g" -e "s/^([0-9a-f]{32})  (.*)/INSERT INTO frozen_files VALUES ('\\1', '\\2');/" $FROZEN_FILE
        echo "END TRANSACTION;"
        echo "CREATE VIEW interesting_files as select *,'frozen' as source from (select * from frozen_files except select * from scanned_files) union select *,'scanned' as source from (select * from scanned_files except select * from frozen_files);"

        #  Moved files are those with a 'frozen' and a 'scanned' entry for the same
        #  checksum but with different names.
        echo "CREATE view moved_files as SELECT i1.checksum, i1.name as name_frozen, i2.name as name_scanned FROM interesting_files as i1, interesting_files as i2 where i1.checksum = i2.checksum and i1.source = 'frozen' and i2.source = 'scanned';"
        echo ".output /tmp/$PROGNAME.$$.moved"
        echo ".width 140"
        echo "SELECT name_frozen || ' --> ' || name_scanned as 'old name --> new name' FROM moved_files order by name_frozen;"
        echo ".output"

        #  Modified files are the opposite: those with a 'frozen' and a 'scanned' entry
        #  for the same name but with different checksums.
        echo "CREATE VIEW modified_files as SELECT i1.checksum as checksum_frozen, i2.checksum as checksum_scanned, i1.name FROM interesting_files as i1, interesting_files as i2 where i1.name = i2.name and i1.source = 'frozen' and i2.source = 'scanned';"
        echo ".output /tmp/$PROGNAME.$$.modified"
        echo ".width 140"
        echo "SELECT name FROM modified_files order by name;"
        echo ".output"

        #  Added files are not moved or modified and have a 'scanned' entry but no
        #  'frozen' entry.
        echo "CREATE VIEW added_files as select checksum, name from (select * from interesting_files except select * from (select checksum_frozen as checksum, name, 'frozen' as source from modified_files union select checksum_scanned as checksum, name, 'scanned' as source from modified_files union select checksum, name_frozen as name, 'frozen' as source from moved_files union select checksum, name_scanned as name, 'scanned' as source from moved_files)) where source = 'scanned';"
        echo ".output /tmp/$PROGNAME.$$.added"
        echo ".width 140"
        echo "SELECT name FROM added_files order by name;"
        echo ".output"

        #  Deleted files are the opposite: those that are are not moved or modified 
        #  and have no 'scanned' entry but do have a 'frozen' entry.
        echo "CREATE VIEW deleted_files as select checksum, name from (select * from interesting_files except select * from (select checksum_frozen as checksum, name, 'frozen' as source from modified_files union select checksum_scanned as checksum, name, 'scanned' as source from modified_files union select checksum, name_frozen as name, 'frozen' as source from moved_files union select checksum, name_scanned as name, 'scanned' as source from moved_files)) where source = 'frozen';"
        echo ".output /tmp/$PROGNAME.$$.deleted"
        echo ".width 140"
        echo "SELECT name FROM deleted_files order by name;"
        echo ".output"
    #  Deliberately hyphen in /tmp/$PROGNAME-$$.sql so rm below doesn't remove it.
    } > /tmp/$PROGNAME-$$.sql
    miniade_debug 10 "compare: running /tmp/$PROGNAME-$$.sql and not deleting it afterwards! ..."
    sqlite3 $DBFILE < /tmp/$PROGNAME-$$.sql

    #  Generate the report including only those sections that have files.
    REPORTED_SOMETHING_FLAG=false
    for SUFFIX in moved modified added deleted; do
        if [ $(stat -c %s /tmp/$PROGNAME.$$.$SUFFIX) != 0 ]; then
            TITLE="$SUFFIX files"
            echo "$TITLE"
            printf "%${#TITLE}.${#TITLE}s\\n" $LOTS_OF_EQUALS
            echo
            cat /tmp/$PROGNAME.$$.$SUFFIX
            echo
            REPORTED_SOMETHING_FLAG=true
        fi
    done
    if $REPORTED_SOMETHING_FLAG; then
        echo "(To save the current state you can run '$PROGNAME --freeze $ROOT_DIR'.)"
    fi

    #  Clean up.
    rm -f /tmp/$PROGNAME.$$.*
}

freeze()
{
    local ROOT_DIR FROZEN_FILE SCANNED_FILE

    #  Process arguments 
    [ $# = 1 ] || miniade_bad_usage
    ROOT_DIR=$1

    #  Sanity checks and derivations
    [[ $ROOT_DIR =~ ^/ ]] || miniade_error "$ROOT_DIR: not absolute"
    FROZEN_FILE=$STATE_DIR/$(zencode <<<"$ROOT_DIR")-frozen.md5sum
    SCANNED_FILE=$STATE_DIR/$(zencode <<<"$ROOT_DIR")-scanned.md5sum
    [ -f $SCANNED_FILE ] || miniade_error "$ROOT_DIR: no scanned file to freeze"

    #  Guts
    miniade_debug 10 "freeze: copying $SCANNED_FILE to $FROZEN_FILE ..."
    cp --preserve=timestamps $SCANNED_FILE $FROZEN_FILE
}

help()
{
    local PROGNAME

    miniade_get_progname PROGNAME
    echo "Usage: $PROGNAME [ <standard-options> ] { --{scan|compare|freeze} [ ... ] <dir> | --list }"
    exit 0
}
   
main "$@"