import sql = require('../services/sql');
import NoteSet = require('../services/search/note_set');
import NotFoundError = require('../errors/not_found_error');
import BOption = require('./entities/boption');
import BNote = require('./entities/bnote');
import BEtapiToken = require('./entities/betapi_token');
import BAttribute = require('./entities/battribute');
import BBranch = require('./entities/bbranch');
import BRevision = require('./entities/brevision');
import BAttachment = require('./entities/battachment');
import { AttachmentRow, RevisionRow } from './entities/rows';
import BBlob = require('./entities/bblob');
import BRecentNote = require('./entities/brecent_note');

interface AttachmentOpts {
    includeContentLength?: boolean;
}

/**
 * Becca is a backend cache of all notes, branches, and attributes.
 * There's a similar frontend cache Froca, and share cache Shaca.
 */
class Becca {
    loaded!: boolean;

    notes!: Record<string, BNote>;
    branches!: Record<string, BBranch>;
    childParentToBranch!: Record<string, BBranch>;
    attributes!: Record<string, BAttribute>;
    /** Points from attribute type-name to list of attributes */
    attributeIndex!: Record<string, BAttribute[]>;
    options!: Record<string, BOption>;
    etapiTokens!: Record<string, BEtapiToken>;

    allNoteSetCache: NoteSet | null;

    constructor() {
        this.reset();
        this.allNoteSetCache = null;
    }

    reset() {
        this.notes = {};
        this.branches = {};
        this.childParentToBranch = {};
        this.attributes = {};        
        this.attributeIndex = {};
        this.options = {};
        this.etapiTokens = {};

        this.dirtyNoteSetCache();

        this.loaded = false;
    }

    getRoot() {
        return this.getNote('root');
    }

    findAttributes(type: string, name: string): BAttribute[] {
        name = name.trim().toLowerCase();

        if (name.startsWith('#') || name.startsWith('~')) {
            name = name.substr(1);
        }

        return this.attributeIndex[`${type}-${name}`] || [];
    }

    findAttributesWithPrefix(type: string, name: string): BAttribute[] {
        const resArr: BAttribute[][] = [];
        const key = `${type}-${name}`;

        for (const idx in this.attributeIndex) {
            if (idx.startsWith(key)) {
                resArr.push(this.attributeIndex[idx]);
            }
        }

        return resArr.flat();
    }

    decryptProtectedNotes() {
        for (const note of Object.values(this.notes)) {
            note.decrypt();
        }
    }

    addNote(noteId: string, note: BNote) {
        this.notes[noteId] = note;
        this.dirtyNoteSetCache();
    }

    getNote(noteId: string): BNote | null {
        return this.notes[noteId];
    }

    getNoteOrThrow(noteId: string): BNote {
        const note = this.notes[noteId];
        if (!note) {
            throw new NotFoundError(`Note '${noteId}' doesn't exist.`);
        }

        return note;
    }

    getNotes(noteIds: string[], ignoreMissing: boolean = false): BNote[] {
        const filteredNotes: BNote[] = [];

        for (const noteId of noteIds) {
            const note = this.notes[noteId];

            if (!note) {
                if (ignoreMissing) {
                    continue;
                }

                throw new Error(`Note '${noteId}' was not found in becca.`);
            }

            filteredNotes.push(note);
        }

        return filteredNotes;
    }

    getBranch(branchId: string): BBranch | null {
        return this.branches[branchId];
    }

    getBranchOrThrow(branchId: string): BBranch | null {
        const branch = this.getBranch(branchId);
        if (!branch) {
            throw new NotFoundError(`Branch '${branchId}' was not found in becca.`);
        }
        return branch;
    }

    getAttribute(attributeId: string): BAttribute | null {
        return this.attributes[attributeId];
    }

    getAttributeOrThrow(attributeId: string): BAttribute {
        const attribute = this.getAttribute(attributeId);
        if (!attribute) {
            throw new NotFoundError(`Attribute '${attributeId}' does not exist.`);
        }

        return attribute;
    }

    getBranchFromChildAndParent(childNoteId: string, parentNoteId: string): BBranch | null {
        return this.childParentToBranch[`${childNoteId}-${parentNoteId}`];
    }

    getRevision(revisionId: string): BRevision | null {
        const row = sql.getRow("SELECT * FROM revisions WHERE revisionId = ?", [revisionId]);

        const BRevision = require('./entities/brevision'); // avoiding circular dependency problems
        return row ? new BRevision(row) : null;
    }

    getAttachment(attachmentId: string, opts: AttachmentOpts = {}): BAttachment | null {
        opts.includeContentLength = !!opts.includeContentLength;

        const query = opts.includeContentLength
            ? `SELECT attachments.*, LENGTH(blobs.content) AS contentLength
               FROM attachments 
               JOIN blobs USING (blobId) 
               WHERE attachmentId = ? AND isDeleted = 0`
            : `SELECT * FROM attachments WHERE attachmentId = ? AND isDeleted = 0`;

        const BAttachment = require('./entities/battachment'); // avoiding circular dependency problems

        return sql.getRows(query, [attachmentId])
            .map(row => new BAttachment(row))[0];
    }

    getAttachmentOrThrow(attachmentId: string, opts: AttachmentOpts = {}): BAttachment {
        const attachment = this.getAttachment(attachmentId, opts);
        if (!attachment) {
            throw new NotFoundError(`Attachment '${attachmentId}' has not been found.`);
        }
        return attachment;
    }

    getAttachments(attachmentIds: string[]): BAttachment[] {
        const BAttachment = require('./entities/battachment'); // avoiding circular dependency problems
        return sql.getManyRows<AttachmentRow>("SELECT * FROM attachments WHERE attachmentId IN (???) AND isDeleted = 0", attachmentIds)
            .map(row => new BAttachment(row));
    }

    getBlob(entity: { blobId: string }): BBlob | null {
        const row = sql.getRow("SELECT *, LENGTH(content) AS contentLength FROM blobs WHERE blobId = ?", [entity.blobId]);

        const BBlob = require('./entities/bblob'); // avoiding circular dependency problems
        return row ? new BBlob(row) : null;
    }

    getOption(name: string): BOption | null {
        return this.options[name];
    }

    getEtapiTokens(): BEtapiToken[] {
        return Object.values(this.etapiTokens);
    }

    getEtapiToken(etapiTokenId: string): BEtapiToken | null {
        return this.etapiTokens[etapiTokenId];
    }

    /** @returns {AbstractBeccaEntity|null} */
    getEntity(entityName: string, entityId: string) {
        if (!entityName || !entityId) {
            return null;
        }

        if (entityName === 'revisions') {
            return this.getRevision(entityId);
        } else if (entityName === 'attachments') {
            return this.getAttachment(entityId);
        }

        const camelCaseEntityName = entityName.toLowerCase().replace(/(_[a-z])/g,
            group =>
                group
                    .toUpperCase()
                    .replace('_', '')
        );

        if (!(camelCaseEntityName in this)) {
            throw new Error(`Unknown entity name '${camelCaseEntityName}' (original argument '${entityName}')`);
        }

        return (this as any)[camelCaseEntityName][entityId];
    }

    getRecentNotesFromQuery(query: string, params = []): BRecentNote[] {
        const rows = sql.getRows(query, params);

        const BRecentNote = require('./entities/brecent_note'); // avoiding circular dependency problems
        return rows.map(row => new BRecentNote(row));
    }

    getRevisionsFromQuery(query: string, params = []): BRevision[] {
        const rows = sql.getRows<RevisionRow>(query, params);

        const BRevision = require('./entities/brevision'); // avoiding circular dependency problems
        return rows.map(row => new BRevision(row));
    }

    /** Should be called when the set of all non-skeleton notes changes (added/removed) */
    dirtyNoteSetCache() {
        this.allNoteSetCache = null;
    }

    getAllNoteSet() {
        // caching this since it takes 10s of milliseconds to fill this initial NoteSet for many notes
        if (!this.allNoteSetCache) {
            const allNotes = [];

            for (const noteId in this.notes) {
                const note = this.notes[noteId];

                // in the process of loading data sometimes we create "skeleton" note instances which are expected to be filled later
                // in case of inconsistent data this might not work and search will then crash on these
                if (note.type !== undefined) {
                    allNotes.push(note);
                }
            }

            this.allNoteSetCache = new NoteSet(allNotes);
        }

        return this.allNoteSetCache;
    }
}

export = Becca;