package be.simplenotes.persistance.notes

import be.simplenotes.domain.model.*
import be.simplenotes.domain.usecases.repositories.NoteRepository
import me.liuwj.ktorm.database.Database
import me.liuwj.ktorm.dsl.*
import me.liuwj.ktorm.entity.*
import java.time.LocalDateTime
import java.util.*
import kotlin.collections.HashMap

internal class NoteRepositoryImpl(private val db: Database) : NoteRepository {

    @Throws(IllegalArgumentException::class)
    override fun findAll(
        userId: Int,
        limit: Int,
        offset: Int,
        tag: String?,
        deleted: Boolean
    ): List<PersistedNoteMetadata> {
        require(limit > 0) { "limit should be positive" }
        require(offset >= 0) { "offset should not be negative" }

        val uuids1: List<UUID>? = if (tag != null) {
            db.from(Tags)
                .leftJoin(Notes, on = Notes.uuid eq Tags.noteUuid)
                .select(Notes.uuid)
                .where { (Notes.userId eq userId) and (Tags.name eq tag) and (Notes.deleted eq deleted) }
                .map { it[Notes.uuid]!! }
        } else null

        var query = db.notes
            .filterColumns { listOf(it.uuid, it.title, it.updatedAt) }
            .filter { (it.userId eq userId) and (it.deleted eq deleted) }

        if (uuids1 != null) query = query.filter { it.uuid inList uuids1 }

        val notes = query
            .sortedByDescending { it.updatedAt }
            .take(limit)
            .drop(offset)
            .toList()

        val tagsByUuid = notes.tagsByUuid()

        return notes.map { note ->
            val tags = tagsByUuid[note.uuid] ?: emptyList()
            note.toPersistedMetadata(tags)
        }
    }

    override fun exists(userId: Int, uuid: UUID): Boolean {
        return db.notes.any { (it.userId eq userId) and (it.uuid eq uuid) and (it.deleted eq false) }
    }

    override fun create(userId: Int, note: Note): PersistedNote {
        val uuid = UUID.randomUUID()
        val entity = note.toEntity(uuid, userId).apply {
            this.updatedAt = LocalDateTime.now()
        }
        db.useTransaction {
            db.notes.add(entity)
            db.batchInsert(Tags) {
                note.meta.tags.forEach { tagName ->
                    item {
                        it.noteUuid to uuid
                        it.name to tagName
                    }
                }
            }
        }

        return entity.toPersistedNote(note.meta.tags)
    }

    override fun find(userId: Int, uuid: UUID): PersistedNote? {
        val note = db.notes
            .filterColumns { it.columns - it.userId }
            .filter { it.uuid eq uuid }
            .find { (it.userId eq userId) and (it.deleted eq false) }
            ?: return null

        val tags = db.from(Tags)
            .select(Tags.name)
            .where { Tags.noteUuid eq uuid }
            .map { it[Tags.name]!! }

        return note.toPersistedNote(tags)
    }

    override fun update(userId: Int, uuid: UUID, note: Note): PersistedNote? {
        db.useTransaction {

            val now = LocalDateTime.now()
            val count = db.update(Notes) {
                it.title to note.meta.title
                it.markdown to note.markdown
                it.html to note.html
                it.updatedAt to now
                where { (it.uuid eq uuid) and (it.userId eq userId) and (it.deleted eq false) }
            }

            if (count == 0) return null

            // delete all tags
            db.delete(Tags) {
                it.noteUuid eq uuid
            }

            // put new ones
            note.meta.tags.forEach { tagName ->
                db.insert(Tags) {
                    it.name to tagName
                    it.noteUuid to uuid
                }
            }

            return PersistedNote(
                meta = note.meta,
                markdown = note.markdown,
                html = note.html,
                updatedAt = now,
                uuid = uuid,
                public = false, // TODO
            )
        }
    }

    override fun delete(userId: Int, uuid: UUID, permanent: Boolean): Boolean {
        return if (!permanent) {
            db.useTransaction {
                db.update(Notes) {
                    it.deleted to true
                    it.updatedAt to LocalDateTime.now()
                    where { it.userId eq userId and (it.uuid eq uuid) }
                }
            } == 1
        } else db.useTransaction {
            db.delete(Notes) { it.uuid eq uuid and (it.userId eq userId) } == 1
        }
    }

    override fun restore(userId: Int, uuid: UUID): Boolean {
        return db.useTransaction {
            db.update(Notes) {
                it.deleted to false
                where { (it.userId eq userId) and (it.uuid eq uuid) }
            } == 1
        }
    }

    override fun getTags(userId: Int): List<String> =
        db.from(Tags)
            .leftJoin(Notes, on = Notes.uuid eq Tags.noteUuid)
            .selectDistinct(Tags.name)
            .where { (Notes.userId eq userId) and (Notes.deleted eq false) }
            .map { it[Tags.name]!! }

    override fun count(userId: Int, tag: String?, deleted: Boolean): Int {
        return if (tag == null) db.notes.count { (it.userId eq userId) and (Notes.deleted eq deleted) }
        else db.sequenceOf(Tags).count {
            (it.name eq tag) and (it.note.userId eq userId) and (it.note.deleted eq deleted)
        }
    }

    override fun export(userId: Int): List<ExportedNote> {

        val notes = db.notes
            .filterColumns { it.columns - it.userId }
            .filter { it.userId eq userId }
            .sortedByDescending { it.updatedAt }
            .toList()

        val tagsByUuid = notes.tagsByUuid()

        return notes.map { note ->
            ExportedNote(
                title = note.title,
                tags = tagsByUuid[note.uuid] ?: emptyList(),
                markdown = note.markdown,
                html = note.html,
                updatedAt = note.updatedAt,
                trash = note.deleted,
            )
        }
    }

    override fun findAllDetails(userId: Int): List<PersistedNote> {
        val notes = db.notes
            .filterColumns { it.columns - it.deleted }
            .filter { (it.userId eq userId) and (it.deleted eq false) }
            .toList()

        val tagsByUuid = notes.tagsByUuid()

        return notes.map { note ->
            val tags = tagsByUuid[note.uuid] ?: emptyList()
            note.toPersistedNote(tags)
        }
    }

    override fun makePublic(userId: Int, uuid: UUID) = db.update(Notes) {
        it.public to true
        where { Notes.userId eq userId and (Notes.uuid eq uuid) and (it.deleted eq false) }
    } == 1

    override fun makePrivate(userId: Int, uuid: UUID) = db.update(Notes) {
        it.public to false
        where { Notes.userId eq userId and (Notes.uuid eq uuid) and (it.deleted eq false) }
    } == 1

    override fun findPublic(uuid: UUID): PersistedNote? {
        val note = db.notes
            .filterColumns { it.columns - it.userId }
            .filter { it.uuid eq uuid }
            .filter { it.public eq true }
            .find { it.deleted eq false }
            ?: return null

        val tags = db.from(Tags)
            .select(Tags.name)
            .where { Tags.noteUuid eq uuid }
            .map { it[Tags.name]!! }

        return note.toPersistedNote(tags)
    }

    private fun List<NoteEntity>.tagsByUuid(): Map<UUID, List<String>> {
        return if (isEmpty()) emptyMap()
        else db.tags
            .filterColumns { listOf(it.noteUuid, it.name) }
            .filter { it.noteUuid inList map { note -> note.uuid } }
            .groupByTo(HashMap(), { it.note.uuid }, { it.name })
    }

}