/* eslint-disable no-use-before-define */
import { docs_v1 as docsV1 } from 'googleapis';
import { isArray } from 'util';
import { EditorState } from 'prosemirror-state';
import { Opt } from '../../../fields/Doc';
import { Networking } from '../../Network';

export const Pulls = 'googleDocsPullCount';
export const Pushes = 'googleDocsPushCount';

export namespace GoogleApiClientUtils {
    export enum Actions {
        Create = 'create',
        Retrieve = 'retrieve',
        Update = 'update',
    }

    export namespace Docs {
        export type RetrievalResult = Opt<docsV1.Schema$Document>;
        export type UpdateResult = Opt<docsV1.Schema$BatchUpdateDocumentResponse>;

        export interface UpdateOptions {
            documentId: DocumentId;
            requests: docsV1.Schema$Request[];
        }

        export enum WriteMode {
            Insert,
            Replace,
        }

        export type DocumentId = string;
        export type Reference = DocumentId | CreateOptions;
        export interface Content {
            text: string | string[];
            requests: docsV1.Schema$Request[];
        }
        export type IdHandler = (id: DocumentId) => unknown;
        export type CreationResult = Opt<DocumentId>;
        export type ReadLinesResult = Opt<{ title?: string; bodyLines?: string[] }>;
        export type ReadResult = { title: string; body: string };
        export interface ImportResult {
            title: string;
            text: string;
            state: EditorState;
        }

        export interface CreateOptions {
            title?: string; // if excluded, will use a default title annotated with the current date
        }

        export interface RetrieveOptions {
            documentId: DocumentId;
        }

        export interface ReadOptions {
            documentId: DocumentId;
            removeNewlines?: boolean;
        }

        export interface WriteOptions {
            mode: WriteMode;
            content: Content;
            reference: Reference;
            index?: number; // if excluded, will compute the last index of the document and append the content there
        }

        /**
         * After following the authentication routine, which connects this API call to the current signed in account
         * and grants the appropriate permissions, this function programmatically creates an arbitrary Google Doc which
         * should appear in the user's Google Doc library instantaneously.
         *
         * @param options the title to assign to the new document, and the information necessary
         * to store the new documentId returned from the creation process
         * @returns the documentId of the newly generated document, or undefined if the creation process fails.
         */
        export const create = async (options: CreateOptions): Promise<CreationResult> => {
            const path = `/googleDocs/Documents/${Actions.Create}`;
            const parameters = {
                requestBody: {
                    title: options.title || `Dash Export (${new Date().toDateString()})`,
                },
            };
            try {
                const schema: docsV1.Schema$Document = await Networking.PostToServer(path, parameters);
                return schema.documentId === null ? undefined : schema.documentId;
            } catch {
                return undefined;
            }
        };

        export namespace Utils {
            export type ExtractResult = { text: string; paragraphs: DeconstructedParagraph[] };
            export const extractText = (document: docsV1.Schema$Document, removeNewlines = false): ExtractResult => {
                const paragraphs = extractParagraphs(document);
                let text = paragraphs
                    .map(paragraph =>
                        paragraph.contents
                            .filter(content => !('inlineObjectId' in content))
                            .map(run => (run as docsV1.Schema$TextRun).content)
                            .join('')
                    )
                    .join('');
                text = text.substring(0, text.length - 1);
                removeNewlines && text.replace(/\n/g, '');
                return { text, paragraphs };
            };

            export type ContentArray = (docsV1.Schema$TextRun | docsV1.Schema$InlineObjectElement)[];
            export type DeconstructedParagraph = { contents: ContentArray; bullet: Opt<number> };
            const extractParagraphs = (document: docsV1.Schema$Document, filterEmpty = true): DeconstructedParagraph[] => {
                const fragments: DeconstructedParagraph[] = [];
                if (document.body && document.body.content) {
                    for (const element of document.body.content) {
                        const runs: ContentArray = [];
                        let bullet: Opt<number>;
                        if (element.paragraph) {
                            if (element.paragraph.elements) {
                                for (const inner of element.paragraph.elements) {
                                    if (inner) {
                                        if (inner.textRun) {
                                            const run = inner.textRun;
                                            (run.content || !filterEmpty) && runs.push(inner.textRun);
                                        } else if (inner.inlineObjectElement) {
                                            runs.push(inner.inlineObjectElement);
                                        }
                                    }
                                }
                            }
                            if (element.paragraph.bullet) {
                                bullet = element.paragraph.bullet.nestingLevel || 0;
                            }
                        }
                        (runs.length || !filterEmpty) && fragments.push({ contents: runs, bullet });
                    }
                }
                return fragments;
            };

            export const endOf = (schema: docsV1.Schema$Document): number | undefined => {
                if (schema.body && schema.body.content) {
                    const paragraphs = schema.body.content.filter(el => el.paragraph);
                    if (paragraphs.length) {
                        const target = paragraphs[paragraphs.length - 1];
                        if (target.paragraph && target.paragraph.elements) {
                            const length = target.paragraph.elements.length;
                            if (length) {
                                const final = target.paragraph.elements[length - 1];
                                return final.endIndex ? final.endIndex - 1 : undefined;
                            }
                        }
                    }
                }
                return undefined;
            };

            export const initialize = async (reference: Reference) => (typeof reference === 'string' ? reference : create(reference));
        }

        export const retrieve = async (options: RetrieveOptions): Promise<RetrievalResult> => {
            const path = `/googleDocs/Documents/${Actions.Retrieve}`;
            try {
                const parameters = { documentId: options.documentId };
                const schema: RetrievalResult = await Networking.PostToServer(path, parameters);
                return schema;
            } catch {
                return undefined;
            }
        };

        export const update = async (options: UpdateOptions): Promise<UpdateResult> => {
            const path = `/googleDocs/Documents/${Actions.Update}`;
            const parameters = {
                documentId: options.documentId,
                requestBody: {
                    requests: options.requests,
                },
            };
            try {
                const replies: UpdateResult = await Networking.PostToServer(path, parameters);
                return replies;
            } catch {
                return undefined;
            }
        };

        export const read = async (options: ReadOptions): Promise<Opt<ReadResult>> =>
            retrieve({ documentId: options.documentId }).then(document => {
                if (document) {
                    const title = document.title!;
                    const body = Utils.extractText(document, options.removeNewlines).text;
                    return { title, body };
                }
                return undefined;
            });

        export const readLines = async (options: ReadOptions): Promise<Opt<ReadLinesResult>> =>
            retrieve({ documentId: options.documentId }).then(document => {
                if (document) {
                    const { title } = document;
                    let bodyLines = Utils.extractText(document).text.split('\n');
                    options.removeNewlines && (bodyLines = bodyLines.filter(line => line.length));
                    return { title: title ?? '', bodyLines };
                }
                return undefined;
            });

        export const setStyle = async (options: UpdateOptions) => {
            const replies = await update({
                documentId: options.documentId,
                requests: options.requests,
            });
            if (replies && 'errors' in replies) {
                console.log('Write operation failed:');
                console.log(replies); //.errors.map((error: any) => error.message));
            }
            return replies;
        };

        export const write = async (options: WriteOptions): Promise<UpdateResult> => {
            const requests: docsV1.Schema$Request[] = [];
            const documentId = await Utils.initialize(options.reference);
            if (!documentId) {
                return undefined;
            }
            let { index } = options;
            const { mode } = options;
            if (!(index && mode === WriteMode.Insert)) {
                const schema = await retrieve({ documentId });
                if (!schema || !(index = Utils.endOf(schema))) {
                    return undefined;
                }
            }
            if (mode === WriteMode.Replace) {
                index > 1 &&
                    requests.push({
                        deleteContentRange: {
                            range: {
                                startIndex: 1,
                                endIndex: index,
                            },
                        },
                    });
                index = 1;
            }
            const { text } = options.content;
            text.length &&
                requests.push({
                    insertText: {
                        text: isArray(text) ? text.join('\n') : text,
                        location: { index },
                    },
                });
            if (!requests.length) {
                return undefined;
            }
            requests.push(...options.content.requests);
            const replies = await update({ documentId, requests });
            if (replies && 'errors' in replies) {
                console.log('Write operation failed:');
                console.log(replies); // .errors.map((error: any) => error.message));
            }
            return replies;
        };
    }
}