/** Accessible, default-off Projects and Conversations workspace for HUX-03. */

import { Folder, GitBranch, Paperclip, Pin, Search } from "lucide-react";
import { useMemo, useState } from "react";
import type { FormEvent } from "react";

import { attachmentViews, branchLineage, projectsEnabled } from "./model.ts";
import type {
  ArtifactSummary,
  Conversation,
  Project,
} from "./types.ts";

interface OrganizationWorkspaceProps {
  flags?: Iterable<string>;
  projects: readonly Project[];
  conversations: readonly Conversation[];
  artifacts?: readonly ArtifactSummary[];
  searchResults?: readonly Conversation[];
  nextSearchCursor?: string | null;
  busy?: boolean;
  error?: string | null;
  onSearch?: (query: string, cursor: string | null) => void;
  onRenameProject?: (project: Project, name: string) => void;
  onRenameConversation?: (conversation: Conversation, title: string) => void;
  onUpdateProjectTags?: (project: Project, tags: string[]) => void;
  onUpdateConversationTags?: (conversation: Conversation, tags: string[]) => void;
  onMoveConversation?: (conversation: Conversation, projectId: string | null) => void;
  onToggleProjectPin?: (project: Project) => void;
  onToggleConversationPin?: (conversation: Conversation) => void;
}

function ordered<T extends {pinned: boolean; updatedAt: string}>(items: readonly T[]): T[] {
  return [...items].sort((left, right) => Number(right.pinned) - Number(left.pinned) ||
    right.updatedAt.localeCompare(left.updatedAt));
}

function Tags({values}: {values: readonly string[]}) {
  if (!values.length) return null;
  return <ul className="hux-org-tags" aria-label="Tags">
    {values.map((tag) => <li key={tag}>{tag}</li>)}
  </ul>;
}

function EditableTitle({label, value, maxLength, onSave}: {
  label: string;
  value: string;
  maxLength: number;
  onSave?: (value: string) => void;
}) {
  const [editing, setEditing] = useState(false);
  const [draft, setDraft] = useState(value);
  if (!onSave) return <span>{value}</span>;
  if (!editing) return <button className="hux-org-title-button" type="button"
    onClick={() => { setDraft(value); setEditing(true); }} aria-label={`${label}: ${value}. Rename`}>
    Rename
  </button>;
  return <form className="hux-org-rename" onSubmit={(event) => {
    event.preventDefault();
    const next = draft.trim();
    if (next && next !== value) onSave(next);
    setEditing(false);
  }}>
    <label><span className="sr-only">{label}</span>
      <input value={draft} maxLength={maxLength} autoFocus onChange={(event) => setDraft(event.target.value)} />
    </label>
    <button type="submit">Save</button>
    <button type="button" onClick={() => setEditing(false)}>Cancel</button>
  </form>;
}

function EditableTags({label, values, onSave}: {
  label: string;
  values: readonly string[];
  onSave?: (values: string[]) => void;
}) {
  const [editing, setEditing] = useState(false);
  const [draft, setDraft] = useState(values.join(", "));
  const [invalid, setInvalid] = useState(false);
  if (!onSave) return <Tags values={values} />;
  if (!editing) return <div><Tags values={values} /><button type="button"
    onClick={() => { setDraft(values.join(", ")); setInvalid(false); setEditing(true); }}>
    Edit tags
  </button></div>;
  return <form className="hux-org-rename" onSubmit={(event) => {
    event.preventDefault();
    const tags = draft.split(",").map((tag) => tag.trim()).filter(Boolean);
    const valid = tags.length <= 32 && new Set(tags).size === tags.length &&
      tags.every((tag) => /^[a-z0-9][a-z0-9-]{0,39}$/.test(tag));
    setInvalid(!valid);
    if (valid) { onSave(tags); setEditing(false); }
  }}>
    <label><span>{label}</span>
      <input value={draft} aria-invalid={invalid} onChange={(event) => setDraft(event.target.value)}
        placeholder="planning, research" />
    </label>
    {invalid && <span role="alert">Use up to 32 lowercase tags separated by commas.</span>}
    <button type="submit">Save tags</button>
    <button type="button" onClick={() => setEditing(false)}>Cancel</button>
  </form>;
}

function ProjectList({projects, selectedId, onSelect, onRename, onTags, onPin}: {
  projects: readonly Project[];
  selectedId: string | null;
  onSelect: (id: string | null) => void;
  onRename?: OrganizationWorkspaceProps["onRenameProject"];
  onTags?: OrganizationWorkspaceProps["onUpdateProjectTags"];
  onPin?: OrganizationWorkspaceProps["onToggleProjectPin"];
}) {
  return <nav className="hux-org-projects" aria-label="Project folders">
    <h2><Folder aria-hidden /> Projects</h2>
    <ul>
      <li><button type="button" aria-current={selectedId === null ? "page" : undefined}
        onClick={() => onSelect(null)}>All conversations</button></li>
      {ordered(projects).map((project) => <li key={project.id} data-pinned={project.pinned}>
        <button className="hux-org-folder" type="button"
          aria-current={selectedId === project.id ? "page" : undefined}
          onClick={() => onSelect(project.id)}>{project.name}</button>
        {onPin && <button className="hux-org-icon" type="button"
          aria-label={`${project.pinned ? "Unpin" : "Pin"} ${project.name}`}
          aria-pressed={project.pinned} onClick={() => onPin(project)}><Pin aria-hidden /></button>}
        {onRename && <EditableTitle label="Project name" value={project.name} maxLength={120}
          onSave={(name) => onRename(project, name)} />}
        <EditableTags label="Project tags" values={project.tags}
          onSave={onTags ? (tags) => onTags(project, tags) : undefined} />
      </li>)}
    </ul>
  </nav>;
}

function Lineage({conversation, conversations}: {
  conversation: Conversation;
  conversations: readonly Conversation[];
}) {
  const nodes = branchLineage(conversation.id, conversations);
  return <section className="hux-org-lineage" aria-labelledby="hux-org-lineage-title">
    <h3 id="hux-org-lineage-title"><GitBranch aria-hidden /> Branch lineage</h3>
    <ol>
      {nodes.map((node) => <li key={`${node.conversationId}-${node.depth}`}
        data-missing={node.missing} data-cycle={node.cycle}>
        <span>{node.title}</span>
        {node.branchPointMessageId && <small>branched at message {node.branchPointMessageId}</small>}
      </li>)}
    </ol>
  </section>;
}

function Attachments({conversation, artifacts}: {
  conversation: Conversation;
  artifacts: readonly ArtifactSummary[];
}) {
  const items = attachmentViews(conversation, artifacts);
  return <section className="hux-org-attachments" aria-labelledby="hux-org-attachments-title">
    <h3 id="hux-org-attachments-title"><Paperclip aria-hidden /> Attached artifacts</h3>
    {items.length ? <ul>{items.map((item) => <li key={item.id} data-missing={item.missing}>
      <span>{item.title}</span><small>{item.missing ? "Still attached; details unavailable" : item.kind}</small>
    </li>)}</ul> : <p>No artifacts attached.</p>}
  </section>;
}

function ConversationList({items, projects, selected, onSelect, onRename, onTags, onMove, onPin}: {
  items: readonly Conversation[];
  projects: readonly Project[];
  selected: string | null;
  onSelect: (id: string) => void;
  onRename?: OrganizationWorkspaceProps["onRenameConversation"];
  onTags?: OrganizationWorkspaceProps["onUpdateConversationTags"];
  onMove?: OrganizationWorkspaceProps["onMoveConversation"];
  onPin?: OrganizationWorkspaceProps["onToggleConversationPin"];
}) {
  return <ul className="hux-org-conversations" aria-label="Conversations">
    {ordered(items).map((conversation) => <li key={conversation.id}
      data-selected={selected === conversation.id} data-pinned={conversation.pinned}>
      <div className="hux-org-conversation-title">
        <button type="button" onClick={() => onSelect(conversation.id)}
          aria-pressed={selected === conversation.id}>{conversation.title}</button>
        {onPin && <button className="hux-org-icon" type="button"
          aria-label={`${conversation.pinned ? "Unpin" : "Pin"} ${conversation.title}`}
          aria-pressed={conversation.pinned} onClick={() => onPin(conversation)}><Pin aria-hidden /></button>}
      </div>
      {onRename && <EditableTitle label="Conversation title" value={conversation.title} maxLength={200}
        onSave={(title) => onRename(conversation, title)} />}
      <EditableTags label="Conversation tags" values={conversation.tags}
        onSave={onTags ? (tags) => onTags(conversation, tags) : undefined} />
      <a className="hux-org-resume" href={`/session/${encodeURIComponent(conversation.id)}`}>
        Resume conversation
      </a>
      {onMove && <label className="hux-org-move">Move to
        <select value={conversation.projectId || ""}
          onChange={(event) => onMove(conversation, event.target.value || null)}>
          <option value="">No project</option>
          {projects.map((project) => <option key={project.id} value={project.id}>{project.name}</option>)}
        </select>
      </label>}
    </li>)}
  </ul>;
}

/** Render nothing unless the negotiated hux.foundation and hux.projects flags are enabled. */
export function OrganizationWorkspace(props: OrganizationWorkspaceProps) {
  const [projectId, setProjectId] = useState<string | null>(null);
  const [selectedId, setSelectedId] = useState<string | null>(null);
  const [query, setQuery] = useState("");
  const enabled = projectsEnabled(props.flags);
  const baseItems = props.searchResults || props.conversations;
  const items = useMemo(() => projectId === null ? baseItems :
    baseItems.filter((item) => item.projectId === projectId), [baseItems, projectId]);
  const selected = props.conversations.find((item) => item.id === selectedId) ||
    items[0] || null;
  if (!enabled) return null;

  function submitSearch(event: FormEvent) {
    event.preventDefault();
    const value = query.trim();
    if (value) props.onSearch?.(value, null);
  }

  return <section className="hux-organization" aria-label="Projects and conversations" aria-busy={props.busy}>
    <ProjectList projects={props.projects} selectedId={projectId} onSelect={setProjectId}
      onRename={props.onRenameProject} onTags={props.onUpdateProjectTags}
      onPin={props.onToggleProjectPin} />
    <main className="hux-org-main">
      <header><h2>Conversations</h2>
        <form role="search" onSubmit={submitSearch}>
          <label htmlFor="hux-org-search">Search conversations, messages, projects, and artifacts</label>
          <div><Search aria-hidden /><input id="hux-org-search" type="search" maxLength={200}
            value={query} onChange={(event) => setQuery(event.target.value)} />
            <button type="submit" disabled={!query.trim() || props.busy}>Search</button></div>
        </form>
      </header>
      {props.error && <p className="hux-org-error" role="alert">{props.error}</p>}
      <p className="sr-only" role="status" aria-live="polite">
        {props.busy ? "Loading conversations" : `${items.length} conversations shown`}
      </p>
      <ConversationList items={items} projects={props.projects} selected={selected?.id || null}
        onSelect={setSelectedId} onRename={props.onRenameConversation}
        onTags={props.onUpdateConversationTags} onMove={props.onMoveConversation}
        onPin={props.onToggleConversationPin} />
      {!items.length && <p className="hux-org-empty">No matching conversations.</p>}
      {props.nextSearchCursor && props.onSearch && <button className="hux-org-more" type="button"
        disabled={props.busy} onClick={() => props.onSearch?.(query.trim(), props.nextSearchCursor || null)}>
        Load more results
      </button>}
    </main>
    <aside className="hux-org-details" aria-label="Conversation details">
      {selected ? <><Lineage conversation={selected} conversations={props.conversations} />
        <Attachments conversation={selected} artifacts={props.artifacts || []} /></> :
        <p>Select a conversation to inspect its lineage and attachments.</p>}
    </aside>
  </section>;
}