"""Tier 0 pipeline: unpaired corpora to aligned relation fields.

Consolidates the components that produced the synthetic world's
end-to-end result, each of which was developed and measured separately:

- watershed object extraction, which splits touching ring members that
  connected components merge (exact object count 74.2% to 100%);
- Gestalt appearance grouping, which assembles members into groups by
  shared colour, size, and shape rather than by a distance threshold
  (exact group count 71.9% to 90.2%);
- size classes from radial extent under one-dimensional k-means per
  member count, because area confounds size with shape and the classes
  are gap-separated rather than equally populated (52.7% to 87.9%);
- text factor families from mutual exclusivity within a group phrase;
- the cross-modal value correspondence from marginal frequency rank.

Nothing crosses modalities except the frequency ranking, and the two
corpora it reads are disjoint: no instance appears on both sides.
"""

from __future__ import annotations

import argparse
import json
from collections import Counter, defaultdict
from pathlib import Path

import numpy as np
import torch
import torch.nn.functional as F
from scipy import ndimage
from scipy.cluster.hierarchy import fcluster, linkage
from sklearn.cluster import KMeans
from tqdm import tqdm

from .common import read_json, seed_everything, write_json
from .synth_cc_battery import moment_field
from .synth_set_battery import parse_group_phrases
from .synth_towers import load_image
from .tier0_dictionary import partition_text_vocabulary, text_token_statistics

NUMBER_TO_COUNT = {"two": 2, "three": 3, "four": 4}
SINGULAR = ("a", "an")


def parse_args() -> argparse.Namespace:
    parser = argparse.ArgumentParser()
    parser.add_argument("--data-dir", default="artifacts/synth_v1")
    parser.add_argument("--split", choices=["val", "test"], default="test")
    parser.add_argument("--samples", type=int, default=256)
    parser.add_argument("--offset", type=int, default=0)
    parser.add_argument("--fit-scenes", type=int, default=1500)
    parser.add_argument("--peak-distance", type=int, default=5)
    parser.add_argument("--group-threshold", type=float, default=0.35)
    parser.add_argument("--views", type=int, default=0, help="0 uses manifest.")
    parser.add_argument("--seed", type=int, default=0)
    parser.add_argument("--output", required=True)
    parser.add_argument("--states-output", default="")
    parser.add_argument(
        "--text-omit",
        default="",
        help="Comma-separated factors the captions never state "
        "(colour, count, size). Vision still sees them.",
    )
    return parser.parse_args()


def extract_objects(image: torch.Tensor, peak_distance: int) -> list[dict]:
    """Foreground objects, splitting touching ones by distance watershed."""
    array = image.permute(1, 2, 0).numpy()
    background = np.median(array.reshape(-1, 3), axis=0)
    foreground = np.abs(array - background).sum(-1) > 0.12
    distance = ndimage.distance_transform_edt(foreground)
    window = 2 * peak_distance + 1
    peaks = (
        distance >= ndimage.maximum_filter(distance, size=window) - 1e-9
    ) & (distance > 1.0)
    labels, count = ndimage.label(peaks)
    if count == 0:
        labels, count = ndimage.label(foreground)
    else:
        while True:
            grown = ndimage.grey_dilation(labels, size=3)
            take = (labels == 0) & foreground & (grown > 0)
            if not take.any():
                break
            labels = np.where(take, grown, labels)
        count = labels.max()
    objects = []
    for index in range(1, count + 1):
        mask = labels == index
        area = float(mask.sum())
        if area < 6:
            continue
        ys, xs = np.nonzero(mask)
        centred_y, centred_x = ys - ys.mean(), xs - xs.mean()
        covariance = np.cov(np.stack([centred_x, centred_y])) + 1e-6 * np.eye(2)
        eigenvalues = np.linalg.eigvalsh(covariance)
        eroded = ndimage.binary_erosion(mask)
        perimeter = max(float((mask & ~eroded).sum()), 1.0)
        box = (xs.max() - xs.min() + 1) * (ys.max() - ys.min() + 1)
        objects.append(
            {
                "rgb": array[mask].mean(0),
                "area": area,
                "extent": float(np.hypot(centred_y, centred_x).max()),
                "shape": np.array(
                    [
                        4 * np.pi * area / perimeter**2,
                        1 - eigenvalues[0] / eigenvalues[1],
                        area / max(box, 1),
                    ]
                ),
            }
        )
    return objects


def appearance(item: dict) -> np.ndarray:
    return np.concatenate(
        [item["rgb"] * 3.0, [np.log(item["area"] + 1e-6) * 0.6], item["shape"]]
    )


def group_objects(objects: list[dict], threshold: float) -> list[dict]:
    """Members of one group share appearance; group by similarity."""
    if not objects:
        return []
    if len(objects) == 1:
        labels = np.array([0])
    else:
        features = np.stack([appearance(item) for item in objects])
        labels = fcluster(linkage(features, "complete"), threshold, "distance")
    buckets: dict[int, list[dict]] = {}
    for item, label in zip(objects, labels):
        buckets.setdefault(int(label), []).append(item)
    return [
        {
            "rgb": np.mean([item["rgb"] for item in members], axis=0),
            "members": len(members),
            "extent": float(np.mean([item["extent"] for item in members])),
        }
        for members in buckets.values()
    ]


class VisionCoder:
    """Colour classes and size classes fitted on the vision corpus alone."""

    def __init__(self, groups: list[dict], classes: int, seed: int) -> None:
        colours = np.stack([group["rgb"] for group in groups]).astype(np.float64)
        self.colour_model = KMeans(classes, n_init=10, random_state=seed).fit(colours)
        frequency = Counter(self.colour_model.labels_.tolist())
        self.colour_rank = {
            label: rank for rank, (label, _) in enumerate(frequency.most_common())
        }
        by_count: dict[int, list[float]] = defaultdict(list)
        for group in groups:
            by_count[min(group["members"], 4)].append(group["extent"])
        self.size_models = {}
        for count, extents in by_count.items():
            model = KMeans(3, n_init=10, random_state=seed).fit(
                np.asarray(extents, dtype=np.float64)[:, None]
            )
            order = np.argsort(model.cluster_centers_[:, 0])
            self.size_models[count] = (
                model,
                {int(label): rank for rank, label in enumerate(order)},
            )

    def encode(self, groups: list[dict], classes: int) -> torch.Tensor:
        if not groups:
            groups = [{"rgb": np.zeros(3), "members": 1, "extent": 1.0}]
        colours = self.colour_model.predict(
            np.stack([group["rgb"] for group in groups]).astype(np.float64)
        )
        vectors = []
        for group, colour in zip(groups, colours):
            model, order = self.size_models[min(group["members"], 4)]
            size = order[
                int(model.predict(np.array([[group["extent"]]], dtype=np.float64))[0])
            ]
            vectors.append(
                factor_vector(self.colour_rank[int(colour)], group["members"], size, classes)
            )
        return F.normalize(torch.stack(vectors), dim=-1)


def factor_vector(colour: int, count: int, size: int, classes: int) -> torch.Tensor:
    vector = torch.zeros(classes + 4 + 3)
    vector[colour] = 1.0
    vector[classes + min(count - 1, 3)] = 1.0
    vector[classes + 4 + size] = 1.0
    return vector


def encode_caption(
    caption: str, colour_rank: dict[str, int], classes: int, omit: frozenset = frozenset()
) -> torch.Tensor:
    """Encode a caption, optionally suppressing factors the text never states.

    Suppressing a factor makes the caption describe strictly less of the scene
    while vision continues to see all of it, which is the controlled form of
    the situation on photographs: a region description and a patch descriptor
    overlap on some aspects and not others. It is the intervention that tests
    whether corpus overlap is what sets the width of the shared spectrum.
    """
    vectors = []
    for phrase in parse_group_phrases(caption):
        tokens = phrase.split()
        colour = next((colour_rank[t] for t in tokens if t in colour_rank), 0)
        count = (
            1
            if any(token in SINGULAR for token in tokens)
            else next(
                (NUMBER_TO_COUNT[t] for t in tokens if t in NUMBER_TO_COUNT), 1
            )
        )
        size = 0 if "small" in tokens else (2 if "large" in tokens else 1)
        vector = factor_vector(colour, count, size, classes)
        if "colour" in omit:
            vector[:classes] = 0.0
        if "count" in omit:
            vector[classes : classes + 4] = 0.0
        if "size" in omit:
            vector[classes + 4 :] = 0.0
        vectors.append(vector)
    if not vectors:
        vectors = [factor_vector(0, 1, 1, classes)]
    stacked = torch.stack(vectors)
    if stacked.abs().sum() == 0:
        stacked = stacked + 1.0
    return F.normalize(stacked, dim=-1)


def moment_state(states: torch.Tensor) -> torch.Tensor:
    first = states.mean(0)
    second = (states[:, :, None] * states[:, None, :]).mean(0).flatten()
    return torch.cat([first, second])


def main() -> None:
    args = parse_args()
    seed_everything(args.seed)
    manifest = read_json(Path(args.data_dir, "manifest.json"))
    captions = read_json(Path(args.data_dir, "captions.json"))["captions"]
    image_dir = Path(manifest["image_dir"])
    views = args.views or manifest["visual_views"]
    rows = manifest[args.split][args.offset : args.offset + args.samples]

    families = partition_text_vocabulary(
        text_token_statistics(captions, manifest["text_only_train"])
    )
    colour_words = families["colour_words"]
    classes = len(colour_words)
    colour_rank = {word: rank for rank, word in enumerate(colour_words)}

    fit_groups = [
        group
        for row in tqdm(
            manifest["vision_only_train"][: args.fit_scenes], desc="fit vision"
        )
        for group in group_objects(
            extract_objects(
                load_image(image_dir / f"scene{row:06d}_v0.png"), args.peak_distance
            ),
            args.group_threshold,
        )
    ]
    coder = VisionCoder(fit_groups, classes, args.seed)

    per_view_fields = []
    view_states = []
    for view in range(views):
        sets = [
            coder.encode(
                group_objects(
                    extract_objects(
                        load_image(image_dir / f"scene{row:06d}_v{view}.png"),
                        args.peak_distance,
                    ),
                    args.group_threshold,
                ),
                classes,
            )
            for row in tqdm(rows, desc=f"encode view {view}")
        ]
        per_view_fields.append(moment_field(sets))
        if view == 0:
            view_states = [moment_state(item) for item in sets]
    visual_field = torch.stack(per_view_fields).mean(0)

    omit = frozenset(f for f in args.text_omit.split(",") if f)
    text_sets = [
        encode_caption(captions[row][0], colour_rank, classes, omit) for row in rows
    ]
    text_field = moment_field(text_sets)

    mask = ~np.eye(len(rows), dtype=bool)
    correlation = float(
        np.corrcoef(
            visual_field.double().numpy()[mask], text_field.double().numpy()[mask]
        )[0, 1]
    )
    torch.save(
        {"visual_field": visual_field, "text_field": text_field, "rows": rows},
        args.output,
    )
    if args.states_output:
        torch.save(
            {
                "vision_states": torch.stack(view_states),
                "text_states": torch.stack([moment_state(item) for item in text_sets]),
                "rows": rows,
            },
            args.states_output,
        )
    summary = {
        "data_dir": args.data_dir,
        "split": args.split,
        "samples": len(rows),
        "colour_classes": classes,
        "text_families": {
            key: families[key] for key in ("count_words", "colour_words", "size_words")
        },
        "field_correlation_at_truth": correlation,
        "note": (
            "The dictionary is derived from disjoint corpora; the "
            "correlation is a diagnostic computed with hidden pairs and "
            "never used by the pipeline."
        ),
    }
    print(json.dumps({"field_correlation_at_truth": correlation}))
    write_json(args.output.replace(".pt", ".json"), summary)
    print(f"Wrote {args.output}")


if __name__ == "__main__":
    main()