#!/usr/bin/env bash
set -ueo pipefail
[ "${DEBUG:-0}" = "1" ] && set -x
# usage:
#   - init - create an empty database
#   - import - import $FILE or import $DIR, both can be multiple values
#   - autoimport ($REGEX|video) $FOLDER - will import all files in $FOLDER with a $REGEX filter,
#                                         or one of the preset filters:
#                                         - video
#   - add (tag|filename) $VALUE - adds a new tag or filename of $VALUE
#   - list (tags|files) - lists all the values in a table
#   - bytag $TAG - list all files by tag label
#   - tag $FILENAME $TAG - tag $FILENAME with $TAG, $TAG can be repeated
#   - listtags $FILENAME - list all tags for $FILENAME

SCRIPT_DIR=$(dirname $(readlink "$0"))
SCRIPT_NAME=$(basename "$0")


DB_FILE="${PWD}/tags.db"
[ "${1:-}" = "--db" ] && DB_FILE="$2" && shift 2


DB_SCHEMA="${SCRIPT_DIR}/database.sql"
declare -A FILTERS
FILTERS[video]="avi|flv|mkv|mov|mp4|mpg|ogv|webm|wmv"


fail() {
    echo "$1" >&2;
    exit 1
}

log() {
    echo "$1"
}

init() {
    # DB_NAME
    [ -f "$1" ] && fail "Database file \"$1\" already exists. Aborting."
    cat "$DB_SCHEMA" | sqlite3 "$1"
    log "Empty database file \"$1\" created."
}

enumerate_positional_parameters() {
    log "Positional parameters in $FUNCNAME:"
    CNT=0
    for VALUE in "$@"; do
        let CNT++ || true
        echo "${CNT}: $VALUE"
    done
}

listtags() {
    # $FILENAME $LIMIT=ALL
    [ -z "$1" ] && fail "No filename supplied."
    FILENAME="$1"
    shift

    ! file_exists_in_db "$FILENAME" && fail "File '$FILENAME' does not exist in database."

    LIMIT="${1:-0}"
    ADDITIONAL_QUERY=""
    [ $LIMIT -gt 0 ] && ADDITIONAL_QUERY="LIMIT $LIMIT"

    sqlite_query \
        "SELECT filename, label from files \
        INNER JOIN tags_ties ON tags_ties.fid = files.id \
        INNER JOIN tags ON tags.id = tags_ties.tid \
        WHERE filename = \"$FILENAME\"\
        $ADDITIONAL_QUERY"
}

add() {
    # $TYPE(tag|path|hash) $VALUE1..$VALUEN
    [ "$1" = "tag" ] && shift && add_tag "$@" && exit 0
    [ "$1" = "path" ] && shift && add_path "$@" && exit 0
    [ "$1" = "hash" ] && shift && add_hash "$@" && exit 0
    [ "$1" = "file" ] && fail "Use \"$SCRIPT_NAME add path\" instead."
    fail "Usage: $SCRIPT_NAME add tag/path/hash"
}

sqlite_query() {
    # $QUERY
    sqlite3 "$DB_FILE" "$1"
}

sqlite_lastrows() {
    # $TABLE $LIMIT
    sqlite_query "SELECT * FROM \"$1\" ORDER BY id DESC LIMIT ${2}"
}

sqlite_insert_single() {
    # $TABLE $COLUMN $VALUES
    # $VALUES can be comma-delimited
    [ -z "$1" ] && fail "No table specified."
    TABLE="$1"
    [ -z "$2" ] && fail "No column(s) supplied."
    COLUMN="$2"
    [ -z "$3" ] && fail "No column values supplied."
    shift 2
    VALUES="(\"$1\")"
    if [[ ! -z "${2:-}" ]]; then
        while true; do
            shift
            [ -z "${1:-}" ] && break
            VALUES+=",(\"$1\")"
        done
    fi
    QUERY="PRAGMA foreign_keys=ON;"
    QUERY+="INSERT INTO $TABLE ($COLUMN) VALUES ${VALUES} RETURNING *;"
    sqlite_query "$QUERY"
}

sqlite_insert_multi() {
    # $TABLE $COLUMN $VALUE1 $VALUE2
    [ -z "$1" ] && fail "No table specified."
    TABLE="$1"
    [ -z "$2" ] && fail "No column(s) supplied."
    COLUMN="$2"
    [[ -z "$3" || -z "$4" ]] && fail "No column values supplied."
    shift 2
    VALUES="($1,$2)"
    if [[ ! -z "${3:-}" && ! -z "${4:-}" ]]; then
        while true; do
            shift
            [ -z "${1:-}" && -z "${2:-}" ] && break
            VALUES+=",($1,$2)"
        done
    fi
    QUERY="PRAGMA foreign_keys=ON;"
    QUERY+="INSERT INTO $TABLE ($COLUMN) VALUES ${VALUES} RETURNING *;"
    sqlite_query "$QUERY"
}

add_tag() {
    # $TAG1...$TAGN
    TABLE="tags"
    COLUMN="label"
    sqlite_insert_single "$TABLE" "$COLUMN" "$@"
}

add_path() {
    # $PATH1..$PATHN
    TABLE="files"
    COLUMN="filename"
    for FILE in "$@"; do
        file_exists_in_db "$FILE" && fail "File '$FILENAME' already exists in database."
    done
    sqlite_insert_single "$TABLE" "$COLUMN" "$@"
}

add_hash() {
    # $FILE $HASH 
    TABLE="hashes"
    COLUMN="fid,md5"
    local FILENAME="${1:-}"
    [ -z "$FILENAME" ] && fail "No file specified."
    ! file_exists_in_db "$FILENAME" && fail "File \"$FILENAME\" does not exist in database."
    sqlite_insert_multi "$TABLE" "$COLUMN" $RESULT "'$2'" 
}

add_path_auto() {
    # $REGEX $FOLDER
    find "${2}" -type f -regextype posix-extended -iregex "$1" -exec "$0" import "{}" +
}

tag_exists_in_db() {
    # $TAGLABEL
    TAG=${1:-}
    RESULT=$(sqlite_query "SELECT id FROM tags WHERE label = '$TAG'")
    if [[ -z "$RESULT" ]]; then
        return 1
    else
        return 0
    fi
}

file_exists_in_db() {
    # $FILENAME
    FILENAME=${1:-}
    RESULT=$(sqlite_query "SELECT id FROM files WHERE filename = '$FILENAME'")
    if [[ -z "$RESULT" ]]; then
        return 1
    else
        return 0
    fi
}

main() {

    [ -z "${1:-}" ] && fail "Usage: tag init/add/import/autoimport/list/listtags"

    if [[ "$1" = "init" ]]; then
        init "${2:-$DB_FILE}"
        exit 0
    fi

    if [[ "$1" = "import" ]]; then
        shift
        add "path" "$@"
    fi

    if [[ "$1" = "autoimport" ]]; then
        shift
        if [[ "${1:-}" =~ "${!FILTERS[@]}" ]]; then
            add_path_auto ".*(${FILTERS[$1]})" "$2"
        else
            add_path_auto "$1" "$2"
        fi
    fi

    if [[ "$1" = "add" ]]; then
        shift
        add "$@"
    fi 

    if [[ "$1" = "list" ]]; then
        [ -z "$2" ] && fail "No table supplied."
        TABLE_NAME="$2"
        sqlite3 -table "$DB_FILE" "SELECT * FROM \"${TABLE_NAME}\""
        exit 0
    fi 

    if [[ "$1" = "bytag" ]]; then
        [ -z "$2" ] && fail "No tag supplied."
        TAG_NAME="$2"
        sqlite3 -table "$DB_FILE" "SELECT filename FROM files WHERE id = (SELECT id FROM tags_ties WHERE id = (SELECT id FROM tags WHERE label = \"${TAG_NAME}\"))"
        exit 0
    fi 

    if [[ "$1" = "tag" ]]; then
        shift
        [ -z "${1:-}" ] && fail "No filename supplied."
        FILENAME="$1"
        ! file_exists_in_db "$FILENAME" && fail "File '$FILENAME' does not exist in database."
        shift
        [ -z "${1:-}" ] && fail "No tag supplied."
        COUNTER=0
        while true; do
            LABEL="$1"
            ! tag_exists_in_db "$LABEL" && fail "Tag '$TAG' does not exist in database."
            shift
            sqlite_query "INSERT INTO tags_ties (fid, tid) VALUES ((SELECT id FROM files WHERE filename = \"$FILENAME\"),(SELECT id FROM tags WHERE label = \"$LABEL\"))"
            COUNTER=$((COUNTER++))
            [ -z "${1:-}" ] && break
        done
        listtags "$FILENAME" "$COUNTER"
        exit 0
    fi 

    if [[ "$1" = "listtags" ]]; then
        [ -z "${2:-}" ] && fail "Usage: $SCRIPT_NAME listtags filename"
        listtags "$2"
        exit 0
    fi 
}

main "$@"