import { Schema } from 'prosemirror-model';
import { tableNodes } from 'prosemirror-tables';

/**
 * The one ProseMirror schema Dorfteich documents are written in (ADR 0004).
 * Editor (TipTap, #25), server-side derivation (this package), and plugin
 * validation (ADR 0008) all import this schema instead of defining their
 * own, so "valid document" means the same thing everywhere.
 *
 * Node names `wikilink`, `plugin_block`, and `transclusion` are reserved for
 * these features (wikilinks #46, plugin-defined block types #76, page embeds
 * #135) — do not repurpose them.
 */
export const editorSchema = new Schema({
  nodes: {
    doc: { content: 'block+' },

    paragraph: {
      group: 'block',
      content: 'inline*',
      parseDOM: [{ tag: 'p' }],
      toDOM: () => ['p', 0],
    },

    heading: {
      group: 'block',
      content: 'inline*',
      defining: true,
      attrs: { level: { default: 1, validate: 'number' } },
      parseDOM: [1, 2, 3, 4].map((level) => ({ tag: `h${level}`, attrs: { level } })),
      toDOM: (node) => [`h${node.attrs.level as number}`, 0],
    },

    blockquote: {
      group: 'block',
      content: 'block+',
      parseDOM: [{ tag: 'blockquote' }],
      toDOM: () => ['blockquote', 0],
    },

    // A styled container for section-style plugins (ADR 0008 kind
    // `section_style`, issue #75). It wraps block content and carries the
    // owning plugin + style ids; the applied CSS is the plugin's sanitized,
    // scoped stylesheet under `.dt-style-<pluginId>-<styleId>`. When the
    // plugin is disabled the class simply resolves to nothing, so the content
    // stays intact with neutral styling.
    section: {
      group: 'block',
      content: 'block+',
      defining: true,
      attrs: {
        pluginId: { default: '', validate: 'string' },
        styleId: { default: '', validate: 'string' },
      },
      parseDOM: [
        {
          tag: 'div[data-section-style]',
          getAttrs: (dom) => {
            const [pluginId = '', styleId = ''] = (
              dom.getAttribute('data-section-style') ?? ''
            ).split('/');
            return { pluginId, styleId };
          },
        },
      ],
      toDOM: (node) => {
        const pluginId = node.attrs.pluginId as string;
        const styleId = node.attrs.styleId as string;
        return [
          'div',
          {
            'data-section-style': `${pluginId}/${styleId}`,
            class: `dt-section dt-style-${pluginId}-${styleId}`,
          },
          0,
        ];
      },
    },

    code_block: {
      group: 'block',
      content: 'text*',
      marks: '',
      code: true,
      defining: true,
      whitespace: 'pre',
      parseDOM: [{ tag: 'pre', preserveWhitespace: 'full' }],
      toDOM: () => ['pre', ['code', 0]],
    },

    // A block owned by a code plugin (ADR 0008 extension point `block`,
    // issue #76): an atom carrying the owning plugin, its block type, and the
    // block's data as a JSON-serializable object. The editor renders it
    // through the plugin's sandboxed iframe; everything else (clipboard,
    // content cache, exports until #79) uses this DOM shape, whose data
    // attributes round-trip the full state — copy/paste never loses data.
    plugin_block: {
      group: 'block',
      atom: true,
      attrs: {
        pluginId: { validate: 'string' },
        blockType: { validate: 'string' },
        data: { default: {} },
      },
      parseDOM: [
        {
          tag: 'div[data-plugin-block]',
          getAttrs: (dom) => {
            const [pluginId = '', blockType = ''] = (
              dom.getAttribute('data-plugin-block') ?? ''
            ).split('/');
            let data: unknown = {};
            try {
              data = JSON.parse(dom.getAttribute('data-plugin-data') ?? '{}');
            } catch {
              // A hand-edited attribute falls back to empty data; the node
              // itself (plugin + type) survives.
            }
            return { pluginId, blockType, data };
          },
        },
      ],
      toDOM: (node) => [
        'div',
        {
          'data-plugin-block': `${node.attrs.pluginId as string}/${node.attrs.blockType as string}`,
          'data-plugin-data': JSON.stringify(node.attrs.data ?? {}),
          class: 'dt-plugin-block',
        },
      ],
    },

    horizontal_rule: {
      group: 'block',
      parseDOM: [{ tag: 'hr' }],
      toDOM: () => ['hr'],
    },

    bullet_list: {
      group: 'block',
      content: 'list_item+',
      parseDOM: [{ tag: 'ul' }],
      toDOM: () => ['ul', 0],
    },

    ordered_list: {
      group: 'block',
      content: 'list_item+',
      attrs: { order: { default: 1, validate: 'number' } },
      parseDOM: [{ tag: 'ol' }],
      toDOM: (node) =>
        node.attrs.order === 1 ? ['ol', 0] : ['ol', { start: node.attrs.order }, 0],
    },

    list_item: {
      content: 'paragraph block*',
      parseDOM: [{ tag: 'li' }],
      toDOM: () => ['li', 0],
    },

    task_list: {
      group: 'block',
      content: 'task_item+',
      parseDOM: [{ tag: 'ul[data-type="task_list"]' }],
      toDOM: () => ['ul', { 'data-type': 'task_list' }, 0],
    },

    task_item: {
      content: 'paragraph block*',
      // `id` (issue #153): a stable per-line id (assigned lazily in the
      // editor) so the task overview (#154) can address a single checkbox for
      // display and server-side toggling. `default: null` keeps every
      // existing document valid; Markdown stays id-less by design.
      attrs: {
        checked: { default: false, validate: 'boolean' },
        id: { default: null },
      },
      parseDOM: [
        {
          tag: 'li[data-type="task_item"]',
          getAttrs: (dom) => ({
            checked: dom.getAttribute('data-checked') === 'true',
            id: dom.getAttribute('data-task-id') || null,
          }),
        },
      ],
      toDOM: (node) => {
        const attrs: Record<string, string> = {
          'data-type': 'task_item',
          'data-checked': String(node.attrs.checked),
        };
        if (node.attrs.id) attrs['data-task-id'] = node.attrs.id as string;
        return ['li', attrs, 0];
      },
    },

    text: { group: 'inline' },

    hard_break: {
      group: 'inline',
      inline: true,
      selectable: false,
      parseDOM: [{ tag: 'br' }],
      toDOM: () => ['br'],
    },

    image: {
      group: 'inline',
      inline: true,
      atom: true,
      attrs: {
        fileId: { validate: 'string' },
        alt: { default: '', validate: 'string' },
        width: { default: null },
      },
      parseDOM: [
        {
          tag: 'img[data-file-id]',
          // No implicit getAttrs: `fileId` has no default (required), so
          // without this ProseMirror's default attr matching (which only
          // applies static `rule.attrs`) would create a node missing it —
          // this is what makes internal copy/paste of an image node work.
          // (No explicit param type: this package has no DOM lib, and the
          // parameter type is inferred from the surrounding NodeSpec anyway.)
          getAttrs: (dom) => {
            const width = dom.getAttribute('width');
            return {
              fileId: dom.getAttribute('data-file-id'),
              alt: dom.getAttribute('alt') ?? '',
              width: width ? Number(width) : null,
            };
          },
        },
      ],
      toDOM: (node) => [
        'img',
        {
          'data-file-id': node.attrs.fileId as string,
          alt: node.attrs.alt as string,
          width: node.attrs.width as number | null,
        },
      ],
    },

    // Obsidian-style `[[page link]]` (ADR 0004, issue #46). An inline atom
    // carrying the target page's `slug` and an optional explicit `displayText`;
    // when `displayText` is null the editor/renderer shows the target's current
    // title, so a rename updates every link. Live title resolution and phantom
    // (missing target) styling happen where the pond's pages are known — the
    // stored document only keeps slug + optional display text.
    wikilink: {
      group: 'inline',
      inline: true,
      atom: true,
      attrs: {
        targetSlug: { validate: 'string' },
        displayText: { default: null },
      },
      parseDOM: [
        {
          tag: 'a[data-wikilink]',
          getAttrs: (dom) => ({
            targetSlug: dom.getAttribute('data-wikilink'),
            displayText: dom.getAttribute('data-display') || null,
          }),
        },
      ],
      toDOM: (node) => {
        const slug = node.attrs.targetSlug as string;
        const display = node.attrs.displayText as string | null;
        const attrs: Record<string, string> = { 'data-wikilink': slug, class: 'wikilink' };
        if (display) attrs['data-display'] = display;
        return ['a', attrs, display ?? slug];
      },
    },

    // Task overview block (issue #154): collects the task-list lines of the
    // current page and its subtree into a table (text, mentioned users,
    // start/due dates, source page) with write-back checkboxes. A block atom
    // without payload — the collection is computed where permissions are
    // known (server-side for the public view, the /read tasks endpoint for
    // the editor's read mode).
    task_overview: {
      group: 'block',
      atom: true,
      parseDOM: [{ tag: 'div[data-task-overview]' }],
      toDOM: () => ['div', { 'data-task-overview': '1', class: 'dt-task-overview' }, 'Tasks'],
    },

    // `>>2026-12-31` / `<<2026-07-01` date marker (issue #152). An inline
    // atom carrying a kind ('due' for `>>`, 'start' for `<<`) and the date as
    // a canonical ISO `YYYY-MM-DD` string; locale-aware formatting happens in
    // the editor, where the viewer's language is known.
    date_marker: {
      group: 'inline',
      inline: true,
      atom: true,
      attrs: {
        kind: { validate: 'string' },
        date: { validate: 'string' },
      },
      parseDOM: [
        {
          tag: 'span[data-date-marker]',
          getAttrs: (dom) => ({
            kind: dom.getAttribute('data-date-marker'),
            date: dom.getAttribute('data-date'),
          }),
        },
      ],
      toDOM: (node) => {
        const kind = node.attrs.kind as string;
        const date = node.attrs.date as string;
        return [
          'span',
          { 'data-date-marker': kind, 'data-date': date, class: `dt-date dt-date--${kind}` },
          `${kind === 'due' ? '»' : '«'} ${date}`,
        ];
      },
    },

    // `@username` user mention (issue #150). An inline atom carrying the
    // mentioned user's stable id plus the username as serialization/display
    // fallback. Live display-name resolution happens in the editor where a
    // user lookup is available; a Markdown import cannot resolve users, so it
    // leaves `userId` empty — such a mention is purely visual.
    mention: {
      group: 'inline',
      inline: true,
      atom: true,
      attrs: {
        userId: { default: '' },
        username: { validate: 'string' },
      },
      parseDOM: [
        {
          tag: 'span[data-mention]',
          getAttrs: (dom) => ({
            username: dom.getAttribute('data-mention'),
            userId: dom.getAttribute('data-mention-user-id') || '',
          }),
        },
      ],
      toDOM: (node) => {
        const username = node.attrs.username as string;
        const userId = node.attrs.userId as string;
        const attrs: Record<string, string> = { 'data-mention': username, class: 'dt-mention' };
        if (userId) attrs['data-mention-user-id'] = userId;
        return ['span', attrs, `@${username}`];
      },
    },

    // Obsidian-style page embed `![[slug]]` (issue #135). A block atom that
    // references another page by slug; the read view / public renderer expands
    // it to the target page's rendered HTML (permission-checked, recursion
    // limited), while the editor shows a placeholder card. Like `wikilink` it
    // stores slug + optional display text only — live resolution happens where
    // the pond's pages are known. The `$[[slug]]` variant (issue #146) sets
    // `bare`: the expansion drops the frame and title, so the embedded content
    // reads as part of the host page.
    transclusion: {
      group: 'block',
      atom: true,
      attrs: {
        targetSlug: { validate: 'string' },
        displayText: { default: null },
        bare: { default: false },
      },
      parseDOM: [
        {
          tag: 'div[data-transclusion]',
          getAttrs: (dom) => ({
            targetSlug: dom.getAttribute('data-transclusion'),
            displayText: dom.getAttribute('data-display') || null,
            bare: dom.getAttribute('data-transclusion-bare') === '1',
          }),
        },
      ],
      toDOM: (node) => {
        const slug = node.attrs.targetSlug as string;
        const display = node.attrs.displayText as string | null;
        const attrs: Record<string, string> = {
          'data-transclusion': slug,
          class: 'dt-transclusion',
        };
        if (display) attrs['data-display'] = display;
        if (node.attrs.bare) attrs['data-transclusion-bare'] = '1';
        return ['div', attrs, display ?? slug];
      },
    },

    ...tableNodes({ tableGroup: 'block', cellContent: 'block+', cellAttributes: {} }),
  },

  marks: {
    bold: {
      parseDOM: [{ tag: 'strong' }, { tag: 'b' }],
      toDOM: () => ['strong', 0],
    },

    italic: {
      parseDOM: [{ tag: 'em' }, { tag: 'i' }],
      toDOM: () => ['em', 0],
    },

    code: {
      parseDOM: [{ tag: 'code' }],
      toDOM: () => ['code', 0],
    },

    strikethrough: {
      parseDOM: [{ tag: 's' }, { tag: 'del' }],
      toDOM: () => ['s', 0],
    },

    link: {
      inclusive: false,
      attrs: { href: { validate: 'string' } },
      parseDOM: [{ tag: 'a[href]' }],
      // `target=_blank` unconditionally: inside the editor (contentEditable)
      // clicking never navigates anyway, and it is what makes "open in new
      // tab" the default behavior in read mode without any extra UI there
      // (issue #29 acceptance criterion) — edit mode gets an explicit
      // bubble-menu action instead (LinkMenu.tsx), since a plain click there
      // only moves the cursor.
      toDOM: (mark) => [
        'a',
        { href: mark.attrs.href as string, target: '_blank', rel: 'noopener noreferrer' },
        0,
      ],
    },
  },
});

/** Link protocols allowed in editor content (security.md §Content). */
export const ALLOWED_LINK_PROTOCOLS = ['http:', 'https:', 'mailto:'] as const;

/** Rejects `javascript:`/`data:`/etc. hrefs; also rejects unparseable input. */
export function isAllowedLinkHref(href: string): boolean {
  try {
    // A base is only needed to resolve protocol-relative/relative inputs;
    // those never carry an executable scheme, so any base works here.
    const url = new URL(href, 'https://dorfteich.invalid');
    return (ALLOWED_LINK_PROTOCOLS as readonly string[]).includes(url.protocol);
  } catch {
    return false;
  }
}