#!/usr/bin/env bash
set -ueo pipefail
# usage:
#   - 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

DB_FILE="tags.db"

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

listtags() {
    # $FILENAME $LIMIT
    [ -z "$1" ] && fail "No filename supplied."
    FILENAME="$1"
    shift
    LIMIT="${1:-0}"

    ADDITIONAL_QUERY=""
    [ $LIMIT -gt 0 ] && ADDITIONAL_QUERY="LIMIT $LIMIT"

    sqlite3 -table "$DB_FILE" \
        "SELECT filename, label from files \
        INNER JOIN tags_ties ON tags_ties.fid = files.fid \
        INNER JOIN tags ON tags.tid = tags_ties.tid \
        WHERE filename = \"$FILENAME\"\
        $ADDITIONAL_QUERY"
}

if [[ "$1" = "add" ]]; then
    shift
    [ "$1" = "tag" ] && TABLE="tags" && COLUMN="label"
    [ "$1" = "file" ] && TABLE="files" && COLUMN="filename"
    shift
    [ -z "$1" ] && fail "No value supplied."
    COUNTER=0
    while true; do
        NEW_TAG="$1"
        shift
        sqlite3 -table "$DB_FILE" "INSERT INTO $TABLE ($COLUMN) VALUES (\"${NEW_TAG}\")"
        COUNTER=$((COUNTER++))
        [ -z "${1:-}" ] && break
    done
    sqlite3 -table "$DB_FILE" "SELECT * FROM \"$TABLE\" LIMIT $COUNTER"
    exit 0
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 fid = (SELECT fid FROM tags_ties WHERE tid = (SELECT tid FROM tags WHERE label = \"${TAG_NAME}\"))"
    exit 0
fi 

if [[ "$1" = "tag" ]]; then
    shift
    [ -z "$1" ] && fail "No filename supplied."
    FILENAME="$1"
    shift
    [ -z "$1" ] && fail "No tag supplied."
    COUNTER=0
    while true; do
        LABEL="$1"
        shift
        sqlite3 -table "$DB_FILE" "INSERT INTO tags_ties (fid, tid) VALUES ((SELECT fid FROM files WHERE filename = \"$FILENAME\"),(SELECT tid FROM tags WHERE label = \"$LABEL\"))"
        COUNTER=$((COUNTER++))
        [ -z "${1:-}" ] && break
    done
    listtags "$FILENAME" "$COUNTER"
    exit 0
fi 

if [[ "$1" = "listtags" ]]; then
    listtags "$2"
    exit 0
fi