import type { EditorState } from "@codemirror/state";
import { foldedRanges, syntaxTree } from "@codemirror/language";
import { Decoration } from "@codemirror/view";
import {
  decoratorStateField,
  HtmlWidget,
  isCursorInRange,
  LinkWidget,
} from "./util.ts";
import type { Client } from "../client.ts";
import {
  frontmatterMailtoRegex,
  frontmatterQuotesRegex,
  frontmatterUrlRegex,
  frontmatterWikiLinkRegex,
} from "../markdown_parser/constants.ts";
import { processWikiLink, type WikiLinkMatch } from "./wiki_link_processor.ts";

export function frontmatterPlugin(client: Client) {
  return decoratorStateField((state: EditorState) => {
    const widgets: any[] = [];
    const foldRanges = foldedRanges(state);
    const shortWikiLinks = client.config.get("shortWikiLinks", true);

    syntaxTree(state).iterate({
      enter(node) {
        if (node.name === "FrontMatterMarker") {
          const parent = node.node.parent!;

          const folded = foldRanges.iter();
          let shouldShowFrontmatterBanner = false;
          while (folded.value) {
            // Check if cursor is in the folded range
            if (isCursorInRange(state, [folded.from, folded.to])) {
              // console.log("Cursor is in folded area, ");
              shouldShowFrontmatterBanner = true;
              break;
            }
            folded.next();
          }
          if (!isCursorInRange(state, [parent.from, parent.to])) {
            widgets.push(
              Decoration.line({
                class: "sb-line-frontmatter-outside",
              }).range(node.from),
            );
            shouldShowFrontmatterBanner = true;
          }
          if (shouldShowFrontmatterBanner && parent.from === node.from) {
            // Only put this on the first line of the frontmatter
            widgets.push(
              Decoration.widget({
                widget: new HtmlWidget(`frontmatter`, "sb-frontmatter-marker"),
              }).range(node.from),
            );
          }
        }

        // Render links inside frontmatter code as clickable anchors (external and wiki links)
        if (node.name === "FrontMatterCode") {
          const oFrom = node.from;
          const oTo = node.to;

          if (isCursorInRange(state, [oFrom, oTo])) {
            return;
          }

          const otext = state.sliceDoc(oFrom, oTo);

          let oMatch: RegExpExecArray | null;
          while ((oMatch = frontmatterQuotesRegex.exec(otext)) !== null) {
            const from = oFrom + (oMatch.index ?? 0);
            const to = from + oMatch[0].length;
            const text = state.sliceDoc(from, to);

            // 1) External links: http(s), <scheme>:// URLs
            frontmatterUrlRegex.lastIndex = 0;
            let match: RegExpExecArray | null;
            while ((match = frontmatterUrlRegex.exec(text)) !== null) {
              const mFrom = from + (match.index ?? 0);
              const mTo = mFrom + match[0].length;
              const url = match[1];
              widgets.push(
                Decoration.replace({
                  widget: new LinkWidget({
                    text: url,
                    title: `Open ${url}`,
                    href: url,
                    cssClass: "sb-external-link",
                    from: mFrom,
                    callback: (e) => {
                      if (e.altKey) {
                        // Move cursor into the link
                        client.editorView.dispatch({
                          selection: { anchor: mFrom },
                        });
                        client.focus();
                        return;
                      }
                      try {
                        // Open http(s) links in a new window/tab, open
                        // alternate schemes in the same page, as they'll
                        // bounce to another application.
                        if (/^https?:\/\//i.test(url)) {
                          globalThis.open(url, "_blank");
                        } else {
                          globalThis.open(url, "_self");
                        }
                      } catch (err) {
                        console.error("Failed to open external link", err);
                      }
                    },
                  }),
                }).range(mFrom, mTo),
              );
            }

            // 2) Internal links: WikiLinks [[...]] (make navigable)
            frontmatterWikiLinkRegex.lastIndex = 0;
            let wMatch: RegExpExecArray | null;
            while ((wMatch = frontmatterWikiLinkRegex.exec(text)) !== null) {
              if (!wMatch || !wMatch.groups) {
                return;
              }
              const mFrom = from + (wMatch.index ?? 0);
              const mTo = mFrom + wMatch[0].length;

              const wikiLinkMatch: WikiLinkMatch = {
                leadingTrivia: wMatch.groups.leadingTrivia,
                stringRef: wMatch.groups.stringRef,
                alias: wMatch.groups.alias,
                trailingTrivia: wMatch.groups.trailingTrivia,
              };

              const decorations = processWikiLink({
                from,
                to,
                match: wikiLinkMatch,
                matchFrom: mFrom,
                matchTo: mTo,
                client,
                shortWikiLinks,
                state,
                callback: (e, ref) => {
                  if (e.altKey) {
                    // Move cursor into the link's content
                    client.editorView.dispatch({
                      selection: {
                        anchor: mFrom + wikiLinkMatch.leadingTrivia.length,
                      },
                    });
                    client.focus();
                    return;
                  }
                  void client.navigate(ref, false, e.ctrlKey || e.metaKey);
                },
              });

              widgets.push(...decorations);
            }

            // 3) mailto:... links
            frontmatterMailtoRegex.lastIndex = 0;
            let mMatch: RegExpExecArray | null;
            while ((mMatch = frontmatterMailtoRegex.exec(text)) !== null) {
              const mFrom = from + (mMatch.index ?? 0);
              const mTo = mFrom + mMatch[0].length;
              const url = mMatch[1];
              const address = url.slice(7);
              widgets.push(
                Decoration.replace({
                  widget: new LinkWidget({
                    text: url,
                    title: `Mail ${address}`,
                    href: url,
                    cssClass: "sb-external-link",
                    from: mFrom,
                    callback: (e) => {
                      if (e.altKey) {
                        // Move cursor into the link
                        client.editorView.dispatch({
                          selection: { anchor: mFrom },
                        });
                        client.focus();
                        return;
                      }
                      try {
                        globalThis.open(url, "_self");
                      } catch (err) {
                        console.error("Failed to open external link", err);
                      }
                    },
                  }),
                }).range(mFrom, mTo),
              );
            }
          }
        }
      },
    });
    return Decoration.set(widgets, true);
  });
}