"use client";

import { type ChangeEvent, type KeyboardEvent, type RefObject, useRef, useState } from "react";
import {
  Bold,
  Code,
  Columns2,
  Columns3,
  FileCode2,
  Heading2,
  Image,
  ImageUp,
  Italic,
  LayoutTemplate,
  Link2,
  List,
  ListOrdered,
  NotebookPen,
  PanelRight,
  Quote,
  Sparkles,
  Strikethrough,
  Table,
} from "lucide-react";
import { toast } from "sonner";
import { Label } from "@/components/ui/label";
import { Textarea } from "@/components/ui/textarea";
import { WikiLinkDialog } from "@/components/frontend/wiki/WikiLinkDialog";
import { WikiEditorHighlightLayer } from "@/components/frontend/wiki/WikiEditorHighlightLayer";
import { WikiTemplateDialog } from "@/components/frontend/wiki/WikiTemplateDialog";
import { useEditorHistory } from "@/components/frontend/wiki/useEditorHistory";
import { uploadWikiImage } from "@/app/(frontend)/wiki/actions";
import type { TemplateMap } from "@/lib/wiki/templates";
import {
  IMAGE_SNIPPET,
  INFOBOX_SNIPPET,
  TABLE_SNIPPET,
  THREE_COLUMN_SNIPPET,
  TWO_COLUMN_SNIPPET,
  createLinePrefixUpdate,
  createListContinueUpdate,
  createFormatUpdate,
  createIndentUpdate,
  createReferenceUpdate,
  createSnippetUpdate,
  createWrappedUpdate,
  readBodySelection,
  type BodyUpdate,
  type SnippetInsertion,
  type WrappedFormat,
} from "@/lib/wiki/editorFormatting";
import {
  WikiEditorToolbar,
  type WikiEditorToolbarAction,
} from "@/components/frontend/wiki/WikiEditorToolbar";

interface WikiEditorBodyProps {
  readonly body: string;
  readonly bodyRef: RefObject<HTMLTextAreaElement | null>;
  readonly existingPages: readonly { title: string }[];
  readonly linkDialogOpen: boolean;
  readonly onBodyChange: (value: string) => void;
  readonly onLinkDialogChange: (open: boolean) => void;
  readonly pending: boolean;
  readonly templates: TemplateMap;
}

export function WikiEditorBody({
  body,
  bodyRef,
  existingPages,
  linkDialogOpen,
  onBodyChange,
  onLinkDialogChange,
  pending,
  templates,
}: WikiEditorBodyProps) {
  const fileInputRef = useRef<HTMLInputElement>(null);
  const mirrorRef = useRef<HTMLDivElement>(null);
  const { record, undo, redo } = useEditorHistory(body, bodyRef);
  const [uploading, setUploading] = useState(false);
  const [templateDialogOpen, setTemplateDialogOpen] = useState(false);

  function syncMirrorScroll(textarea: HTMLTextAreaElement) {
    if (mirrorRef.current) mirrorRef.current.scrollTop = textarea.scrollTop;
  }

  function scrollCaretIntoView(caret: number) {
    const textarea = bodyRef.current;
    const mirror = mirrorRef.current;
    if (!textarea || !mirror || caret < 0) return;

    const walker = document.createTreeWalker(mirror, NodeFilter.SHOW_TEXT);
    let remaining = caret;
    let node = walker.nextNode() as Text | null;
    let lastNode = node;
    while (node && remaining > (node.textContent?.length ?? 0)) {
      remaining -= node.textContent?.length ?? 0;
      lastNode = node;
      node = walker.nextNode() as Text | null;
    }
    const target = node ?? lastNode;
    if (!target) return;
    const offset = Math.min(remaining, target.textContent?.length ?? 0);

    const range = document.createRange();
    try {
      range.setStart(target, offset);
    } catch {
      return;
    }
    range.collapse(true);

    const mirrorRect = mirror.getBoundingClientRect();
    const caretTop =
      range.getBoundingClientRect().top - mirrorRect.top + mirror.scrollTop;
    const lineHeight = parseFloat(getComputedStyle(textarea).lineHeight) || 20;
    const viewTop = textarea.scrollTop;
    const viewBottom = viewTop + textarea.clientHeight - lineHeight;
    if (caretTop < viewTop || caretTop > viewBottom) {
      textarea.scrollTop = Math.max(0, caretTop - textarea.clientHeight / 2);
      syncMirrorScroll(textarea);
    }
  }

  async function handleFileChange(event: ChangeEvent<HTMLInputElement>) {
    const file = event.target.files?.[0];
    event.target.value = "";
    if (!file) return;

    setUploading(true);
    try {
      const formData = new FormData();
      formData.append("file", file);
      const result = await uploadWikiImage(formData);
      if (!result.success || !result.data) {
        toast.error(result.error ?? "Upload failed.");
        return;
      }
      const { url, alt } = result.data;
      insertSnippet({ insertion: `![${alt}](${url})`, placeholder: alt });
      toast.success("Image uploaded.");
    } catch {
      toast.error("Upload failed.");
    } finally {
      setUploading(false);
    }
  }

  function applyBodyUpdate(update: BodyUpdate, recordHistory = true) {
    if (recordHistory) {
      record(update.value, update.selectionStart, update.selectionEnd, false);
    }
    onBodyChange(update.value);
    requestAnimationFrame(() => {
      requestAnimationFrame(() => {
        const textarea = bodyRef.current;
        if (!textarea) return;
        textarea.focus();
        textarea.setSelectionRange(update.selectionStart, update.selectionEnd);
        scrollCaretIntoView(update.selectionStart);
        syncMirrorScroll(textarea);
      });
    });
  }

  function handleBodyChange(event: ChangeEvent<HTMLTextAreaElement>) {
    const { value, selectionStart, selectionEnd } = event.target;
    record(value, selectionStart, selectionEnd, true);
    onBodyChange(value);
  }

  function wrapSelection(format: WrappedFormat) {
    const selection = readBodySelection(body, bodyRef);
    applyBodyUpdate(createWrappedUpdate(body, selection, format));
  }

  function prefixLines(prefix: string) {
    const selection = readBodySelection(body, bodyRef);
    applyBodyUpdate(createLinePrefixUpdate(body, selection, prefix));
  }

  function insertSnippet(snippet: SnippetInsertion) {
    const selection = readBodySelection(body, bodyRef);
    applyBodyUpdate(createSnippetUpdate(body, selection, snippet));
  }

  function insertReference(definitionSuffix: string) {
    const selection = readBodySelection(body, bodyRef);
    applyBodyUpdate(createReferenceUpdate(body, selection, { definitionSuffix }));
  }

  function insertWikilink(pageTitle: string) {
    const selection = readBodySelection(body, bodyRef);
    applyBodyUpdate(
      createSnippetUpdate(body, selection, {
        insertion: `[[${pageTitle}]]`,
      }),
    );
    onLinkDialogChange(false);
  }

  function insertTemplateBody(value: string) {
    const selection = readBodySelection(body, bodyRef);
    applyBodyUpdate(
      createSnippetUpdate(body, selection, { insertion: value }),
    );
    setTemplateDialogOpen(false);
  }

  function formatBody() {
    const selection = readBodySelection(body, bodyRef);
    applyBodyUpdate(createFormatUpdate(body, selection));
  }

  function handleBodyKeyDown(event: KeyboardEvent<HTMLTextAreaElement>) {
    if (event.nativeEvent.isComposing) return;

    if ((event.metaKey || event.ctrlKey) && !event.altKey) {
      const undoKey = event.key.toLowerCase();
      if (undoKey === "z") {
        event.preventDefault();
        const entry = event.shiftKey ? redo() : undo();
        if (entry) applyBodyUpdate(entry, false);
        return;
      }
      if (undoKey === "y" && !event.shiftKey) {
        event.preventDefault();
        const entry = redo();
        if (entry) applyBodyUpdate(entry, false);
        return;
      }
    }

    if (event.key === "Tab") {
      event.preventDefault();
      const selection = readBodySelection(body, bodyRef);
      const update = createIndentUpdate(body, selection, event.shiftKey);
      if (update) applyBodyUpdate(update);
      return;
    }

    if (event.key === "Enter" && !event.shiftKey && !event.metaKey && !event.ctrlKey && !event.altKey) {
      const selection = readBodySelection(body, bodyRef);
      const update = createListContinueUpdate(body, selection);
      if (update) {
        event.preventDefault();
        applyBodyUpdate(update);
      }
      return;
    }

    const modifierPressed = event.metaKey || event.ctrlKey;
    if (!modifierPressed || event.altKey) return;

    const key = event.key.toLowerCase();
    if (key === "b" && !event.shiftKey) {
      event.preventDefault();
      wrapSelection({ prefix: "**", suffix: "**", placeholder: "bold text" });
      return;
    }
    if (key === "i" && !event.shiftKey) {
      event.preventDefault();
      wrapSelection({ prefix: "*", suffix: "*", placeholder: "italic text" });
      return;
    }
    if (key === "x" && event.shiftKey) {
      event.preventDefault();
      wrapSelection({ prefix: "~~", suffix: "~~", placeholder: "strikethrough text" });
      return;
    }
    if (key === "h" && event.shiftKey) {
      event.preventDefault();
      prefixLines("## ");
      return;
    }
    if (key === "f" && event.shiftKey) {
      event.preventDefault();
      formatBody();
      return;
    }
    if (key === "k" && !event.shiftKey) {
      event.preventDefault();
      onLinkDialogChange(true);
      return;
    }
    if (key === "e" && !event.shiftKey) {
      event.preventDefault();
      wrapSelection({ prefix: "`", suffix: "`", placeholder: "code" });
      return;
    }

    const browserComboKeys = new Set(["b", "i", "e", "k", "h", "u"]);
    if (browserComboKeys.has(key)) {
      event.preventDefault();
    }
  }

  const groups: readonly (readonly WikiEditorToolbarAction[])[] = [
    [
      {
        label: "Bold",
        shortcut: "Ctrl/Cmd+B",
        icon: Bold,
        onClick: () => wrapSelection({ prefix: "**", suffix: "**", placeholder: "bold text" }),
      },
      {
        label: "Italic",
        shortcut: "Ctrl/Cmd+I",
        icon: Italic,
        onClick: () => wrapSelection({ prefix: "*", suffix: "*", placeholder: "italic text" }),
      },
      {
        label: "Strikethrough",
        shortcut: "Ctrl/Cmd+Shift+X",
        icon: Strikethrough,
        onClick: () =>
          wrapSelection({ prefix: "~~", suffix: "~~", placeholder: "strikethrough text" }),
      },
      {
        label: "Heading",
        shortcut: "Ctrl/Cmd+Shift+H",
        icon: Heading2,
        onClick: () => prefixLines("## "),
      },
      {
        label: "Format",
        shortcut: "Ctrl/Cmd+Shift+F",
        icon: Sparkles,
        onClick: formatBody,
      },
    ],
    [
      {
        label: "Inline code",
        shortcut: "Ctrl/Cmd+E",
        icon: Code,
        onClick: () => wrapSelection({ prefix: "`", suffix: "`", placeholder: "code" }),
      },
      {
        label: "Code block",
        icon: FileCode2,
        onClick: () =>
          wrapSelection({ prefix: "```\n", suffix: "\n```", placeholder: "code block" }),
      },
      { label: "Quote", icon: Quote, onClick: () => prefixLines("> ") },
    ],
    [
      { label: "Bulleted list", icon: List, onClick: () => prefixLines("- ") },
      { label: "Numbered list", icon: ListOrdered, onClick: () => prefixLines("1. ") },
      {
        label: "Table",
        icon: Table,
        onClick: () => insertSnippet({ insertion: TABLE_SNIPPET, placeholder: "Header" }),
      },
    ],
    [
      {
        label: "Wikilink",
        shortcut: "Ctrl/Cmd+K",
        icon: Link2,
        onClick: () => onLinkDialogChange(true),
      },
      {
        label: "Captioned image",
        icon: Image,
        onClick: () => insertSnippet({ insertion: IMAGE_SNIPPET, placeholder: "Alt text" }),
      },
      {
        label: "Upload image",
        icon: ImageUp,
        onClick: () => fileInputRef.current?.click(),
      },
      { label: "Footnote", icon: NotebookPen, onClick: () => insertReference("") },
      {
        label: "Citation",
        icon: NotebookPen,
        onClick: () => insertReference('Author, "Title", <URL>'),
      },
    ],
    [
      {
        label: "Infobox",
        icon: PanelRight,
        onClick: () => insertSnippet({ insertion: INFOBOX_SNIPPET, placeholder: "Infobox title" }),
      },
      {
        label: "2 columns",
        icon: Columns2,
        onClick: () =>
          insertSnippet({ insertion: TWO_COLUMN_SNIPPET, placeholder: "Left column content" }),
      },
      {
        label: "3 columns",
        icon: Columns3,
        onClick: () =>
          insertSnippet({ insertion: THREE_COLUMN_SNIPPET, placeholder: "Left column content" }),
      },
      {
        label: "Template",
        icon: LayoutTemplate,
        onClick: () => setTemplateDialogOpen(true),
      },
    ],
  ];

  return (
    <div className="flex flex-col gap-1.5">
      <input
        ref={fileInputRef}
        type="file"
        accept="image/*"
        className="hidden"
        onChange={handleFileChange}
      />
      <div className="flex flex-wrap items-center justify-between gap-2">
        <Label htmlFor="wiki-body">Body</Label>
        <WikiLinkDialog
          open={linkDialogOpen}
          onOpenChange={onLinkDialogChange}
          existingPages={existingPages}
          onSelect={insertWikilink}
          disabled={pending}
        />
      </div>
      <WikiTemplateDialog
        templates={templates}
        open={templateDialogOpen}
        onOpenChange={setTemplateDialogOpen}
        disabled={pending}
        onInsert={insertTemplateBody}
      />
      <WikiEditorToolbar groups={groups} disabled={pending || uploading} />
      <div className="relative min-h-[23.5rem] w-full rounded-md border border-input bg-transparent shadow-sm transition-[box-shadow] focus-within:border-ring focus-within:ring-1 focus-within:ring-ring lg:h-[calc(100vh-10rem)]">
        <WikiEditorHighlightLayer body={body} ref={mirrorRef} />
        <Textarea
          ref={bodyRef}
          id="wiki-body"
          value={body}
          onChange={handleBodyChange}
          onScroll={(event) => syncMirrorScroll(event.currentTarget)}
          onKeyDown={handleBodyKeyDown}
          placeholder="Write the field guide entry in Markdown."
          disabled={pending}
          className="absolute inset-0 h-full w-full resize-none border-0 bg-transparent font-mono text-sm text-transparent caret-foreground shadow-none selection:bg-primary/30 focus-visible:outline-none focus-visible:ring-0"
        />
      </div>
    </div>
  );
}