/**
 * EditorProposalController — F12/#64 editor surface (spec coauthoring-inline-editor-diff
 * §3.5). Reverses INV-32 for pending proposals: on `onDidChangeProposals` it
 * (1) optimistically applies any not-yet-applied proposal into the active editor's
 * buffer (ProposalController.optimisticApply, INV-48), (2) decorates each applied
 * proposal — insertion tint over the proposed text + a non-editable struck-red hint
 * for deletions (INV-52, decorationPlan/INV-49), and (3) provides a CodeLens
 * `Accept ▾ / Reject ▾` above each block whose ▾ opens a QuickPick (this / all).
 * Owns no proposal STATE — it is a view over ProposalController (which stays the
 * pure F4 owner). Phase 2 decorates ALL committed changes-since-baseline by author
 * (human green / Claude blue + struck hints for deletions), plus pending proposals;
 * a pinned baseline suppresses committed marks entirely (pin→clean, INV-48).
 */
import * as vscode from "vscode";
import type { ProposalController } from "./proposalController";
import type { DiffViewController } from "./diffViewController";
import type { AttributionController } from "./attributionController";
import { decorationPlan, wordEditHunks, authorAt } from "./trackChangesModel";
import { isAuthorable } from "./workspacePath";
import type { CoeditingRegistry } from "./coeditingRegistry";

export class EditorProposalController implements vscode.Disposable, vscode.CodeLensProvider {
  private readonly disposables: vscode.Disposable[] = [];
  private readonly insDeco: Record<"human" | "claude", vscode.TextEditorDecorationType> = {
    human: vscode.window.createTextEditorDecorationType({
      backgroundColor: "rgba(63,185,80,0.14)", borderColor: "#3fb950",
      border: "0 0 2px 0", borderStyle: "solid",
    }),
    claude: vscode.window.createTextEditorDecorationType({
      backgroundColor: "rgba(88,166,255,0.15)", borderColor: "#58a6ff",
      border: "0 0 2px 0", borderStyle: "solid",
    }),
  };
  private readonly delDeco: Record<"human" | "claude" | "none", vscode.TextEditorDecorationType> = {
    human: vscode.window.createTextEditorDecorationType({ after: { color: "#f85149" } }),
    claude: vscode.window.createTextEditorDecorationType({ after: { color: "#bc8cff" } }),
    none: vscode.window.createTextEditorDecorationType({ after: { color: new vscode.ThemeColor("descriptionForeground") } }),
  };
  private readonly lensEmitter = new vscode.EventEmitter<void>();
  readonly onDidChangeCodeLenses = this.lensEmitter.event;
  /** Pending debounce timers — one per URI — coalesce rapid-fire propose events
   * (e.g. runEditAndPropose's N sequential propose() calls) into a single
   * optimistic-apply pass that runs after ALL proposals are created. Without this,
   * each propose() fires onDidChangeProposals synchronously and the controller's
   * optimisticApply runs concurrently with the still-in-progress propose loop,
   * causing "file changed in the meantime" workspace-edit conflicts. */
  private readonly pendingApply = new Map<string, ReturnType<typeof setTimeout>>();
  /** Debounce timers for committed-change re-render (one per URI, 50 ms). */
  private readonly pendingRender = new Map<string, ReturnType<typeof setTimeout>>();

  constructor(
    private readonly proposals: ProposalController,
    private readonly diffView: DiffViewController,
    private readonly attribution: AttributionController,
    private readonly registry: CoeditingRegistry,
  ) {
    this.disposables.push(
      this.insDeco.human, this.insDeco.claude, this.delDeco.human, this.delDeco.claude, this.delDeco.none, this.lensEmitter,
      vscode.languages.registerCodeLensProvider({ language: "markdown" }, this),
      this.proposals.onDidChangeProposals(({ uri }) => this.scheduleApply(uri)),
      vscode.window.onDidChangeActiveTextEditor((ed) => ed && this.renderEditor(ed)),
      // Refresh committed decorations when the baseline changes (establish / pin / head-refresh).
      this.diffView.onDidChangeBaseline(({ uri }) => {
        const ed = vscode.window.visibleTextEditors.find((e) => e.document.uri.toString() === uri);
        if (ed) this.renderEditor(ed);
      }),
      // Refresh committed decorations (debounced) when the active doc changes — attribution spans shift.
      vscode.workspace.onDidChangeTextDocument((e) => {
        const ed = vscode.window.activeTextEditor;
        if (ed && e.document === ed.document) this.scheduleRender(ed);
      }),
      // INV-10: re-render (and refresh CodeLens) on every gate change — exit clears
      // decorations/CodeLens via renderEditor's own gate check, re-entry redraws.
      this.registry.onDidChange(({ uri }) => {
        const ed = vscode.window.visibleTextEditors.find((e) => e.document.uri.toString() === uri);
        if (ed) this.renderEditor(ed);
        this.lensEmitter.fire();
      }),
      // the four QuickPick-backed menu commands
      vscode.commands.registerCommand("cowriting.proposalAcceptMenu", (id?: string) => this.menu("accept", id)),
      vscode.commands.registerCommand("cowriting.proposalRejectMenu", (id?: string) => this.menu("reject", id)),
    );
  }

  /** Debounce-schedule an optimistic-apply pass for the given URI. Multiple rapid
   * onDidChangeProposals events (from a single runEditAndPropose batch) collapse
   * into one pass that runs after the batch completes. */
  private scheduleApply(uri: string): void {
    const prev = this.pendingApply.get(uri);
    if (prev !== undefined) clearTimeout(prev);
    this.pendingApply.set(
      uri,
      setTimeout(() => {
        this.pendingApply.delete(uri);
        void this.onProposalsChanged(uri);
      }, 0),
    );
  }

  /** Debounce a committed-change re-render for `editor` (50 ms — lets rapid typing settle). */
  private scheduleRender(editor: vscode.TextEditor): void {
    const uri = editor.document.uri.toString();
    const prev = this.pendingRender.get(uri);
    if (prev !== undefined) clearTimeout(prev);
    this.pendingRender.set(
      uri,
      setTimeout(() => {
        this.pendingRender.delete(uri);
        this.renderEditor(editor);
      }, 50),
    );
  }

  /** Apply any not-yet-applied proposals on the doc, then re-decorate + refresh lenses. */
  private async onProposalsChanged(uri: string): Promise<void> {
    const doc = vscode.workspace.textDocuments.find((d) => d.uri.toString() === uri);
    if (!doc || doc.languageId !== "markdown" || !isAuthorable(doc.uri.scheme)) return;
    // INV-10: a doc that exited coediting between the schedule and this tick gets
    // no optimistic-apply/decorations/CodeLens.
    if (!this.registry.isCoediting(doc.uri)) return;
    const key = this.proposals.keyFor(doc);
    for (const v of this.proposals.listProposals(doc)) {
      if (v.anchorStart !== null && !this.proposals.isApplied(key, v.id)) {
        await this.proposals.optimisticApply(doc, v.id); // fires onDidChangeProposals again; guarded by isApplied
      }
    }
    const ed = vscode.window.visibleTextEditors.find((e) => e.document.uri.toString() === uri);
    if (ed) this.renderEditor(ed);
    this.lensEmitter.fire();
  }

  /** Decorate the editor for every applied proposal on its document (INV-52). */
  private renderEditor(editor: vscode.TextEditor): void {
    const doc = editor.document;
    const clearAll = () => {
      for (const a of ["human", "claude"] as const) editor.setDecorations(this.insDeco[a], []);
      for (const a of ["human", "claude", "none"] as const) editor.setDecorations(this.delDeco[a], []);
    };
    if (doc.languageId !== "markdown") return clearAll();
    // INV-10: a non-entered doc gets no decorations at all.
    if (!this.registry.isCoediting(doc.uri)) return clearAll();
    const key = this.proposals.keyFor(doc);
    const ins: Record<"human" | "claude", vscode.Range[]> = { human: [], claude: [] };
    const del: Record<"human" | "claude" | "none", vscode.DecorationOptions[]> = { human: [], claude: [], none: [] };
    // Pending proposals — always Claude (INV: proposals are agent-authored).
    for (const v of this.proposals.listProposals(doc)) {
      if (v.anchorStart === null || v.original === undefined || !this.proposals.isApplied(key, v.id)) continue;
      const plan = decorationPlan(v.anchorStart, v.original, v.replacement);
      for (const i of plan.insertions) ins.claude.push(new vscode.Range(doc.positionAt(i.start), doc.positionAt(i.end)));
      for (const d of plan.deletions) {
        del.claude.push({
          range: new vscode.Range(doc.positionAt(d.at), doc.positionAt(d.at)),
          renderOptions: { after: { contentText: ` ${d.text} `, textDecoration: "line-through" } },
        });
      }
    }
    // Committed changes-since-baseline are added by decorateCommitted (pushes into ins/del[author]).
    this.decorateCommitted(editor, ins, del);
    for (const a of ["human", "claude"] as const) editor.setDecorations(this.insDeco[a], ins[a]);
    for (const a of ["human", "claude", "none"] as const) editor.setDecorations(this.delDeco[a], del[a]);
  }

  /**
   * Decorates committed (non-proposal) changes-since-baseline by author (Task 7 / reverse INV-32).
   * Diffs current buffer against the F6 baseline; attributes each changed run to its author;
   * skips any hunk overlapping an applied pending proposal (the proposal loop owns those).
   * pin→clean: returns without marking when baseline.reason === "pinned".
   * Adjacency heuristic: a deletion in a hunk that has insertions inherits the hunk author;
   * a standalone deletion (hunk with no insertions) renders neutral ("none") — matching the
   * preview's cw-del-none treatment.
   */
  private decorateCommitted(
    editor: vscode.TextEditor,
    ins: Record<"human" | "claude", vscode.Range[]>,
    del: Record<"human" | "claude" | "none", vscode.DecorationOptions[]>,
  ): void {
    const doc = editor.document;
    const baseline = this.diffView.getBaseline(doc.uri.toString());
    // No baseline yet, or baseline was pinned (pin→clean: no committed marks, INV-48).
    if (!baseline || baseline.reason === "pinned") return;
    const current = doc.getText();
    // Nothing changed — short-circuit before the diff.
    if (current === baseline.text) return;
    const spans = this.attribution.spansFor(doc);
    const key = this.proposals.keyFor(doc);
    // Build the set of current-buffer ranges owned by applied pending proposals so we
    // can skip hunks that fall inside them — the proposal loop already decorates those.
    const appliedRanges: { start: number; end: number }[] = [];
    for (const v of this.proposals.listProposals(doc)) {
      if (v.anchorStart !== null && v.original !== undefined && this.proposals.isApplied(key, v.id)) {
        appliedRanges.push({ start: v.anchorStart, end: v.anchorStart + v.replacement.length });
      }
    }
    // wordEditHunks(current, baseline.text): start/end are in current coords; replacement is baseline text.
    const hunks = wordEditHunks(current, baseline.text);
    for (const h of hunks) {
      // Skip hunks whose current-buffer range overlaps an applied pending proposal.
      // The skip is whole-hunk and therefore conservative: a committed edit word-merged
      // into a proposal's hunk is skipped entirely — rare at word granularity.
      if (appliedRanges.some((r) => h.start < r.end && h.end > r.start)) continue;
      const author = authorAt(h.start, spans) ?? "human";
      // h.replacement = baseline text for this span; current.slice(h.start, h.end) = applied text.
      const plan = decorationPlan(h.start, h.replacement, current.slice(h.start, h.end));
      for (const i of plan.insertions) {
        ins[author].push(new vscode.Range(doc.positionAt(i.start), doc.positionAt(i.end)));
      }
      // Adjacency heuristic: a deletion paired with an insertion in THIS hunk inherits the
      // insertion author; a standalone deletion (no insertion in the hunk) is neutral.
      const delAuthor = plan.insertions.length > 0 ? author : "none";
      for (const d of plan.deletions) {
        del[delAuthor].push({
          range: new vscode.Range(doc.positionAt(d.at), doc.positionAt(d.at)),
          renderOptions: { after: { contentText: ` ${d.text} `, textDecoration: "line-through" } },
        });
      }
    }
  }

  /**
   * CodeLensProvider (Task 8, PUC-2 wording): a `✓ Keep` / `✗ Reject` pair above
   * each applied block, plus — when ≥2 proposals are pending on the doc — a
   * top-of-file `✓ Keep all (N)` / `✗ Reject all` pair routed directly at the
   * batch commands (no QuickPick detour for the common "review is done" case).
   */
  provideCodeLenses(document: vscode.TextDocument): vscode.CodeLens[] {
    if (document.languageId !== "markdown") return [];
    if (!this.registry.isCoediting(document.uri)) return [];
    const key = this.proposals.keyFor(document);
    const applied = this.proposals
      .listProposals(document)
      .filter((v) => v.anchorStart !== null && this.proposals.isApplied(key, v.id));
    const lenses: vscode.CodeLens[] = [];
    if (applied.length >= 2) {
      const top = new vscode.Range(0, 0, 0, 0);
      lenses.push(
        new vscode.CodeLens(top, { title: `✓ Keep all (${applied.length})`, command: "cowriting.acceptAllProposals" }),
        new vscode.CodeLens(top, { title: "✗ Reject all", command: "cowriting.rejectAllProposals" }),
      );
    }
    for (const v of applied) {
      const pos = document.positionAt(v.anchorStart!);
      const line = new vscode.Range(pos.line, 0, pos.line, 0);
      lenses.push(
        new vscode.CodeLens(line, { title: "✓ Keep", command: "cowriting.proposalAcceptMenu", arguments: [v.id] }),
        new vscode.CodeLens(line, { title: "✗ Reject", command: "cowriting.proposalRejectMenu", arguments: [v.id] }),
      );
    }
    return lenses;
  }

  /** The dropdown: this-proposal vs all-proposals, then dispatch. */
  private async menu(kind: "accept" | "reject", id?: string): Promise<void> {
    const doc = vscode.window.activeTextEditor?.document;
    if (!doc || !id) return;
    const key = this.proposals.keyFor(doc);
    const verb = kind === "accept" ? "Accept" : "Reject";
    const pick = await vscode.window.showQuickPick(
      [`${verb} this proposal`, `${verb} ALL proposals`],
      { placeHolder: `${verb} Claude's proposal` },
    );
    if (!pick) return;
    const all = pick.includes("ALL");
    if (kind === "accept") {
      if (all) await this.proposals.acceptAllProposals(doc);
      else await this.proposals.finalizeInPlace(key, id);
    } else {
      if (all) await this.proposals.rejectAll(doc);
      else await this.proposals.revertInPlace(key, id);
    }
  }

  dispose(): void {
    for (const t of this.pendingApply.values()) clearTimeout(t);
    this.pendingApply.clear();
    for (const t of this.pendingRender.values()) clearTimeout(t);
    this.pendingRender.clear();
    for (const d of this.disposables) d.dispose();
  }
}