import { syntaxTree } from "@codemirror/language";
import { EditorView, ViewPlugin, type ViewUpdate } from "@codemirror/view";
import type { Client } from "../client.ts";

import { lezerToParseTree } from "../markdown_parser/parse_tree.ts";
import {
  addParentPointers,
  findParentMatching,
  nodeAtPos,
} from "@silverbulletmd/silverbullet/lib/tree";
import { maximumDocumentSize } from "@silverbulletmd/silverbullet/constants";
import { safeRun } from "@silverbulletmd/silverbullet/lib/async";
import { resolveMarkdownLink } from "@silverbulletmd/silverbullet/lib/resolve";
import { localDateString } from "@silverbulletmd/silverbullet/lib/dates";
import type { UploadFile } from "@silverbulletmd/silverbullet/type/client";
import { isValidName, isValidPath } from "@silverbulletmd/silverbullet/lib/ref";
import TurndownService from "turndown";
// @ts-expect-error - No type definitions available for this package
import { tables, taskListItems } from "@joplin/turndown-plugin-gfm";

const turndownService = new TurndownService({
  hr: "---",
  codeBlockStyle: "fenced",
  headingStyle: "atx",
  emDelimiter: "*",
  bulletListMarker: "*", // Duh!
  strongDelimiter: "**",
  linkStyle: "inlined",
});
turndownService.use(taskListItems);
turndownService.use(tables);

function striptHtmlComments(s: string): string {
  return s.replace(/<!--[\s\S]*?-->/g, "");
}

function ensureValidFilenameWithExtension(filename: string): string {
  if (isValidPath(filename)) {
    return filename;
  }
  const match = filename.match(/\.([^.]+)$/);
  return `file.${match ? match[1] : "txt"}`;
}

async function doesFileExist(
  editor: Client,
  filePath: string,
): Promise<boolean> {
  try {
    await editor.space.spacePrimitives.getFileMeta(filePath);
    return true;
  } catch {
    return false;
  }
}

const urlRegexp =
  /^https?:\/\/[-a-zA-Z0-9@:%._+~#=]{1,256}([-a-zA-Z0-9()@:%_+.~#?&//=]*)/;

// Known iOS Safari paste issue (unrelated to this implementation): https://voxpelli.com/2015/03/ios-safari-url-copy-paste-bug/
export const pasteLinkExtension = ViewPlugin.fromClass(
  class {
    update(update: ViewUpdate): void {
      update.transactions.forEach((tr) => {
        if (tr.isUserEvent("input.paste")) {
          const pastedText: string[] = [];
          let from = 0;
          let to = 0;
          tr.changes.iterChanges((fromA, _toA, _fromB, toB, inserted) => {
            pastedText.push(inserted.sliceString(0));
            from = fromA;
            to = toB;
          });
          const pastedString = pastedText.join("");
          if (pastedString.match(urlRegexp)) {
            const selection = update.startState.selection.main;
            if (!selection.empty) {
              setTimeout(() => {
                update.view.dispatch({
                  changes: [
                    {
                      from: from,
                      to: to,
                      insert: `[${update.startState.sliceDoc(
                        selection.from,
                        selection.to,
                      )}](${pastedString})`,
                    },
                  ],
                });
              });
            }
          }
        }
      });
    }
  },
);

export function documentExtension(editor: Client) {
  let shiftDown = false;
  return EditorView.domEventHandlers({
    dragover: (event) => {
      event.preventDefault();
    },
    keydown: (event) => {
      if (event.key === "Shift") {
        shiftDown = true;
      }
      return false;
    },
    keyup: (event) => {
      if (event.key === "Shift") {
        shiftDown = false;
      }
      return false;
    },
    drop: (event: DragEvent) => {
      // TODO: This doesn't take into account the target cursor position,
      // it just drops the document wherever the cursor was last.
      if (event.dataTransfer) {
        const payload = [...event.dataTransfer.files];
        if (!payload.length) {
          return;
        }
        safeRun(async () => {
          await processFileTransfer(payload);
        });
      }
    },
    paste: (event: ClipboardEvent) => {
      const payload = [...event.clipboardData!.items];
      const richText = event.clipboardData?.getData("text/html");

      // Only do rich text paste if shift is NOT down
      if (richText && !shiftDown) {
        // Are we in a fenced code block?
        const editorText = editor.editorView.state.sliceDoc();
        const tree = lezerToParseTree(
          editorText,
          syntaxTree(editor.editorView.state).topNode,
        );
        addParentPointers(tree);
        const currentNode = nodeAtPos(
          tree,
          editor.editorView.state.selection.main.from,
        );
        if (currentNode) {
          const fencedParentNode = findParentMatching(currentNode, (t) =>
            ["FrontMatter", "FencedCode"].includes(t.type!),
          );
          if (
            fencedParentNode ||
            ["FrontMatter", "FencedCode"].includes(currentNode.type!)
          ) {
            console.log("Inside of fenced code block, not pasting rich text");
            return false;
          }
        }

        event.preventDefault();
        const markdown = striptHtmlComments(
          turndownService.turndown(richText),
        ).trim();
        const view = editor.editorView;
        const selection = view.state.selection.main;
        view.dispatch({
          changes: [
            {
              from: selection.from,
              to: selection.to,
              insert: markdown,
            },
          ],
          selection: {
            anchor: selection.from + markdown.length,
          },
          scrollIntoView: true,
        });
        return true;
      }
      if (!payload.length || payload.length === 0) {
        return false;
      }
      safeRun(async () => {
        await processItemTransfer(payload);
      });
    },
  });

  async function processFileTransfer(payload: File[]) {
    const data = await payload[0].arrayBuffer();
    // data.byteLength > maximumDocumentSize;
    const fileData: UploadFile = {
      name: payload[0].name,
      contentType: payload[0].type,
      content: new Uint8Array(data),
    };
    await saveFile(fileData);
  }

  async function processItemTransfer(payload: DataTransferItem[]) {
    const file = payload.find((item) => item.kind === "file");
    if (!file) {
      return false;
    }
    const fileType = file.type;
    const ext = fileType.split("/")[1];
    const fileName = localDateString(new Date())
      .split(".")[0]
      .replace("T", "_")
      .replaceAll(":", "-");
    const data = await file!.getAsFile()?.arrayBuffer();
    if (!data) {
      return false;
    }
    const fileData: UploadFile = {
      name: `${fileName}.${ext}`,
      contentType: fileType,
      content: new Uint8Array(data),
    };
    await saveFile(fileData);
  }

  async function saveFile(file: UploadFile) {
    const maxSize = maximumDocumentSize;
    const invalidPathMessage =
      "Unable to upload file, invalid target filename or path";

    if (file.content.length > maxSize * 1024 * 1024) {
      editor.ui.flashNotification(
        `Document is too large, maximum is ${maxSize}MiB`,
        "error",
      );
      return;
    }

    let desiredFilePath = await editor.ui.prompt(
      "File name for pasted document",
      resolveMarkdownLink(
        client.currentPath(),
        ensureValidFilenameWithExtension(file.name),
      ),
    );
    if (desiredFilePath === undefined) {
      // User hit cancel, so they know why we stopped and dont need an notification.
      return;
    }
    desiredFilePath = desiredFilePath.trim();
    if (!isValidName(desiredFilePath)) {
      editor.ui.flashNotification(invalidPathMessage, "error");
      return;
    }

    // Check the given desired file path wont clobber an existing file. If it
    // would, ask the user to confirm or provide another filename. Repeat this
    // check for every new filename they give.
    // Note: duplicate any modifications here to client/code_mirror/editor_paste.ts
    let finalFilePath = null;
    while (finalFilePath == null) {
      if (await doesFileExist(editor, desiredFilePath)) {
        let confirmedFilePath = await editor.ui.prompt(
          "A file with that name already exists, keep the same name to replace it, or rename your file",
          resolveMarkdownLink(
            client.currentPath(),
            ensureValidFilenameWithExtension(desiredFilePath),
          ),
        );
        if (confirmedFilePath === undefined) {
          // Unlike the initial filename prompt, we're inside a workflow here
          // and should be explicit that the user action cancelled the whole
          // operation.
          editor.ui.flashNotification("Upload cancelled by user", "info");
          return;
        }
        confirmedFilePath = confirmedFilePath.trim();
        if (!isValidPath(confirmedFilePath)) {
          editor.ui.flashNotification(invalidPathMessage, "error");
          return;
        }
        if (desiredFilePath === confirmedFilePath) {
          // if we got back the same path, we're replacing and should accept the given name
          finalFilePath = desiredFilePath;
        } else {
          // we got a new path, so we must repeat the check
          desiredFilePath = confirmedFilePath;
          confirmedFilePath = undefined;
        }
      } else {
        finalFilePath = desiredFilePath;
      }
    }

    await editor.space.writeDocument(finalFilePath, file.content);
    let documentMarkdown = `[[${finalFilePath}]]`;
    if (file.contentType.startsWith("image/")) {
      documentMarkdown = `!${documentMarkdown}`;
    }
    editor.editorView.dispatch({
      changes: [
        {
          insert: documentMarkdown,
          from: editor.editorView.state.selection.main.from,
        },
      ],
    });
  }
}