/**
 * Bridge between the Studio drag system and GSAP animations running in the
 * preview iframe.
 *
 * The preview iframe exposes `window.gsap` with a `getProperty(element, prop)`
 * method that returns the ACTUAL interpolated value at the current seek time.
 * This module reads those runtime values so that drag commits can write correct
 * absolute positions back into the GSAP script, regardless of tween type,
 * easing, or seek position.
 */
import type { GsapAnimation, PropertyGroupName } from "@hyperframes/core/gsap-parser";
import type { DomEditSelection } from "../components/editor/domEditingTypes";
import { usePlayerStore } from "../player/store/playerStore";

import { readAllAnimatedProperties, readGsapProperty } from "./gsapRuntimeReaders";
import { commitGsapPositionFromDrag } from "./gsapDragPositionCommit";
import {
  commitStaticGsapPosition,
  commitStaticGsapRotation,
  commitWholePathOffset,
  computeCurrentPercentage,
  findExistingPositionWrite,
  findRotationSetAnimation,
  materializeIfDynamic,
} from "./gsapDragCommit";
import { commitWholePropertyOffset } from "./gsapWholePropertyOffsetCommit";
import { resolveTweenDuration } from "../utils/globalTimeCompiler";
import type { GsapDragCommitCallbacks } from "./gsapDragCommit";
import { isInstantHold, selectorFromSelection } from "./gsapShared";
import {
  findGsapPositionAnimation,
  pickClosestToPlayhead,
  readGsapPositionFromIframe,
} from "./gsapPositionDetection";
import { hasNonHoldTweenForElement } from "./gsapRuntimeKeyframes";

// Position channels — used to scope the "has a live position tween?" check so a
// sibling rotation/scale animation never forces a static position hold into the
// keyframe branch (which corrupts it into a frozen duration-0 keyframed tween).
export const POSITION_CHANNELS = [
  "x",
  "y",
  "xPercent",
  "yPercent",
  "left",
  "top",
  // GSAP normalizes translateX/Y to x/y at play time, but readTween reads the
  // AUTHORED shape — include them so a hand-authored translateX/Y position tween
  // still counts as a live position tween.
  "translateX",
  "translateY",
];

// ── Property-group tween resolution ───────────────────────────────────────

/**
 * Find the tween for a given property group, splitting a legacy mixed tween
 * if necessary. Returns the resolved animation or null if none exists.
 *
 * Resolution order:
 * 1. Tween already tagged with `propertyGroup === group`
 * 2. Legacy mixed tween (`!propertyGroup`) → split via server mutation,
 *    re-fetch, then return the group tween
 * 3. null — caller must handle the missing-tween case
 */
export async function resolveGroupTween(
  group: PropertyGroupName,
  animations: GsapAnimation[],
  selection: DomEditSelection,
  commitMutation: GsapDragCommitCallbacks["commitMutation"],
  fetchFallbackAnimations?: () => Promise<GsapAnimation[]>,
): Promise<{ anim: GsapAnimation; animations: GsapAnimation[] } | null> {
  // 1. Already-split group tween — pick the one closest to the current
  // playhead so a drag at t=6s edits the tween at 4s, not the one at 1.5s.
  const groupAnims = animations.filter((a) => a.propertyGroup === group);
  const groupAnim = pickClosestToPlayhead(groupAnims);
  if (groupAnim) return { anim: groupAnim, animations };

  // 2. Legacy mixed tween — split it, then re-fetch
  const legacyMixed = animations.find((a) => !a.propertyGroup);
  if (legacyMixed) {
    await commitMutation(
      selection,
      { type: "split-into-property-groups", animationId: legacyMixed.id },
      { label: "Split mixed tween into property groups", skipReload: true },
    );
    if (fetchFallbackAnimations) {
      const fresh = await fetchFallbackAnimations();
      const freshGroupAnim = fresh.find((a) => a.propertyGroup === group);
      if (freshGroupAnim) return { anim: freshGroupAnim, animations: fresh };
    }
  }

  // 3. Try fallback fetch (no split needed, just wasn't in the initial list)
  if (!legacyMixed && fetchFallbackAnimations) {
    const fresh = await fetchFallbackAnimations();
    const freshGroupAnim = fresh.find((a) => a.propertyGroup === group);
    if (freshGroupAnim) return { anim: freshGroupAnim, animations: fresh };

    // Fallback: legacy mixed in the fresh list
    const freshLegacy = fresh.find((a) => !a.propertyGroup);
    if (freshLegacy) {
      await commitMutation(
        selection,
        { type: "split-into-property-groups", animationId: freshLegacy.id },
        { label: "Split mixed tween into property groups", skipReload: true },
      );
      const reFetched = await fetchFallbackAnimations();
      const reFetchedGroup = reFetched.find((a) => a.propertyGroup === group);
      if (reFetchedGroup) return { anim: reFetchedGroup, animations: reFetched };
    }
  }

  return null;
}

// ── High-level intercept ───────────────────────────────────────────────────

export type { GsapDragCommitCallbacks };

/**
 * Attempt to handle a drag commit via the GSAP script mutation path.
 *
 * Returns a Promise that resolves to true if the drag was handled via GSAP
 * (caller should skip the CSS path), or false if no GSAP position animation
 * exists.
 */
// fallow-ignore-next-line complexity
export async function tryGsapDragIntercept(
  selection: DomEditSelection,
  offset: { x: number; y: number },
  animations: GsapAnimation[],
  iframe: HTMLIFrameElement | null,
  commitMutation: GsapDragCommitCallbacks["commitMutation"],
  fetchFallbackAnimations?: () => Promise<GsapAnimation[]>,
  options?: { altKey?: boolean },
): Promise<boolean> {
  const selector = selectorFromSelection(selection);
  if (!selector) {
    return false;
  }

  // Self-heal: enforce a single position write BEFORE committing. A corrupted
  // file can carry 2+ conflicting position writes for one selector (e.g. a
  // degenerate `tl.to(...,{duration:0,x,y})` AND a `gsap.set(...,{x,y})`) — the
  // later one silently overrides the earlier, so the element "can't move". Keep
  // the live keyframed/real tween if present (else any), strip the rest, so the
  // commit below updates ONE write instead of fighting duplicates.
  let workingAnimations = animations;
  const isPosWrite = (a: GsapAnimation) =>
    a.targetSelector === selector && a.propertyGroup === "position";
  if (animations.filter(isPosWrite).length > 1 && fetchFallbackAnimations) {
    const fresh = await fetchFallbackAnimations();
    const dupes = fresh.filter(isPosWrite);
    if (dupes.length > 1) {
      const keeper =
        dupes.find((a) => a.keyframes) ?? dupes.find((a) => (a.duration ?? 0) > 0) ?? dupes[0]!;
      await commitMutation(
        selection,
        {
          type: "consolidate-position-writes",
          targetSelector: selector,
          keepAnimationId: keeper.id,
        },
        { label: "Consolidate position writes", skipReload: true },
      );
      workingAnimations = await fetchFallbackAnimations();
    } else {
      workingAnimations = fresh;
    }
  }

  const resolved = await resolveGroupTween(
    "position",
    workingAnimations,
    selection,
    commitMutation,
    fetchFallbackAnimations,
  );

  let posAnim = resolved?.anim ?? null;
  let resolvedAnimations = resolved?.animations ?? workingAnimations;
  if (!posAnim) {
    posAnim = findGsapPositionAnimation(workingAnimations, selector);
    if (!posAnim && fetchFallbackAnimations) {
      const fresh = await fetchFallbackAnimations();
      resolvedAnimations = fresh;
      posAnim = findGsapPositionAnimation(fresh, selector);
    }
  }

  const gsapPos = readGsapPositionFromIframe(iframe, selector) ?? { x: 0, y: 0 };

  // STATIC case (single source of truth = GSAP timeline): the element has no LIVE
  // keyframed/tweened position motion. Use the strict non-hold check — a leftover
  // position-hold `set` (after a delete-all, or a stale parse that lags it) must
  // NOT count as live motion. Either way the position belongs in a
  // `tl.set("#el",{x,y})`, not a keyframe conversion: re-nudge an existing set in
  // place (idempotent), else add a new one. This also covers the stale-cache
  // phantom — committing a set is correct because the element genuinely has no live motion.
  const hasNonHold = hasNonHoldTweenForElement(iframe, selector, undefined, POSITION_CHANNELS);
  // A KEYFRAMED position tween — even one that's currently a flat constant ("hold",
  // e.g. 0% and 100% identical) — is still an animation the user is building, so a
  // drag must add/update a keyframe, NOT fall back to a static `set`. Without this,
  // dragging an element whose position tween is constant writes a `gsap.set` that
  // fights the tween (the "drag didn't create a keyframe / didn't persist" bug). The
  // static path is only for elements with NO keyframed position tween (truly static,
  // or just a leftover position-hold `set`).
  // A zero-duration keyframed tween is a static HOLD, not a live animation —
  // treat it as static so the drag heals it instead of feeding it more keyframes.
  const hasKeyframedPosTween = !!posAnim?.keyframes && resolveTweenDuration(posAnim) > 0;
  if (!hasNonHold && !hasKeyframedPosTween) {
    const existingSet =
      posAnim && isInstantHold(posAnim) && posAnim.targetSelector === selector
        ? posAnim
        : findExistingPositionWrite(resolvedAnimations, selector);
    await commitStaticGsapPosition(selection, offset, gsapPos, selector, existingSet, {
      commitMutation,
      fetchAnimations: fetchFallbackAnimations,
    });
    return true;
  }

  if (!posAnim) {
    return false;
  }

  // Verify the anim ID is still valid in the current file. The React-state
  // `animations` list can lag behind the file after a prior mutation changed
  // the tween's position/method (which changes the ID). Re-fetch to get the
  // current ID and avoid a stale-ID remove that creates duplicate tweens.
  if (fetchFallbackAnimations) {
    const fresh = await fetchFallbackAnimations();
    const freshMatch = fresh.find(
      (a) =>
        a.targetSelector === posAnim!.targetSelector && a.propertyGroup === posAnim!.propertyGroup,
    );
    if (freshMatch && freshMatch.id !== posAnim.id) {
      posAnim = freshMatch;
    }
  }

  const cbs = { commitMutation, fetchAnimations: fetchFallbackAnimations };
  // Alt-drag already means "shift the whole path" — the global auto-keyframe
  // toggle (#1808) just makes that the default while it's off, so a manual
  // edit on an already-animated element nudges the animation instead of
  // inserting/updating a keyframe at the playhead.
  const autoKeyframeEnabled = usePlayerStore.getState().autoKeyframeEnabled;
  if (options?.altKey || !autoKeyframeEnabled) {
    await commitWholePathOffset(selection, posAnim, offset, gsapPos, iframe, selector, cbs);
  } else {
    await commitGsapPositionFromDrag(selection, posAnim, offset, gsapPos, iframe, selector, cbs);
  }
  return true;
}

// ── Runtime property readers (re-exported for external callers) ───────────

export { readGsapProperty, readAllAnimatedProperties };

// ── Identity-prop synthesis ───────────────────────────────────────────────

export async function tryGsapRotationIntercept(
  selection: DomEditSelection,
  angle: number,
  animations: GsapAnimation[],
  iframe: HTMLIFrameElement | null,
  commitMutation: GsapDragCommitCallbacks["commitMutation"],
  fetchFallbackAnimations?: () => Promise<GsapAnimation[]>,
): Promise<boolean> {
  const selector = selectorFromSelection(selection);
  if (!selector) return false;

  // Resolve the rotation-group tween, splitting legacy mixed tweens if needed.
  const resolved = await resolveGroupTween(
    "rotation",
    animations,
    selection,
    commitMutation,
    fetchFallbackAnimations,
  );
  const resolvedAnimations = resolved?.animations ?? animations;

  // Fallback: legacy heuristic for hand-written scripts
  let anim = resolved?.anim ?? null;
  if (!anim) {
    anim = animations.find((a) => "rotation" in a.properties || a.keyframes) ?? null;
    if (!anim && fetchFallbackAnimations) {
      const fresh = await fetchFallbackAnimations();
      anim = fresh.find((a) => "rotation" in a.properties || a.keyframes) ?? null;
    }
  }

  // `angle` is the ABSOLUTE target rotation resolved by the gesture (gsap base +
  // pointer sweep) or the inspector — so it IS the new rotation. No base re-add: the
  // gesture's live preview already gsap.set this value (single source of truth).
  const newRotation = Math.round(angle);
  // STATIC case (single source of truth = GSAP timeline): no rotation tween, so the
  // angle belongs in a `tl.set("#el",{rotation})`, not a keyframe conversion —
  // mirroring the static position set. Idempotent: re-rotate updates an existing
  // rotation set in place, else add a new one. This replaces the old
  // `--hf-studio-rotation` CSS-var fallback (the same dual-channel bug class).
  if (!anim || isInstantHold(anim)) {
    const existingSet = anim ?? findRotationSetAnimation(resolvedAnimations, selector);
    await commitStaticGsapRotation(selection, newRotation, selector, existingSet, {
      commitMutation,
      fetchAnimations: fetchFallbackAnimations,
    });
    return true;
  }

  const pct = computeCurrentPercentage(selection, anim);

  // With auto-keyframe off (#1808), a rotation tween already exists for this
  // element (checked above) so nudge it as a whole rather than adding a
  // keyframe at the playhead.
  if (!usePlayerStore.getState().autoKeyframeEnabled) {
    await commitWholePropertyOffset(
      selection,
      anim,
      { rotation: newRotation },
      pct,
      iframe,
      { commitMutation, fetchAnimations: fetchFallbackAnimations },
      "Rotate animation",
    );
    return true;
  }

  // fallow-ignore-next-line code-duplication
  if (anim.hasUnresolvedKeyframes || anim.hasUnresolvedSelector) {
    const newId = await materializeIfDynamic(anim, iframe, commitMutation, selection);
    if (newId) anim = { ...anim, id: newId };
  } else if (!anim.keyframes) {
    const resolvedFromValues = selector
      ? readAllAnimatedProperties(iframe, selector, anim, "rotation")
      : undefined;
    await commitMutation(
      selection,
      { type: "convert-to-keyframes", animationId: anim.id, resolvedFromValues },
      { label: "Convert to keyframes for rotation", skipReload: true },
    );
  }

  const runtimeProps = readAllAnimatedProperties(iframe, selector, anim, "rotation");

  const backfillDefaults: Record<string, number> = { ...runtimeProps };
  if (!("rotation" in runtimeProps)) {
    backfillDefaults.rotation = readGsapProperty(iframe, selector, "rotation") ?? 0;
  }

  const properties = { ...runtimeProps, rotation: newRotation };

  await commitMutation(
    selection,
    {
      type: "add-keyframe",
      animationId: anim.id,
      percentage: pct,
      properties,
      backfillDefaults,
    },
    { label: `Rotate (keyframe ${pct}%)`, softReload: true },
  );
  return true;
}

export { readRuntimeKeyframes, scanAllRuntimeKeyframes } from "./gsapRuntimeKeyframes";