"""
Publish diffusion CI ground-truth images to sgl-project/ci-data
via the GitHub API (same pattern as publish_traces.py).
"""

import argparse
import base64
import hashlib
import io
import json
import os
import sys
from dataclasses import dataclass
from pathlib import Path
from urllib.error import HTTPError

import numpy as np
from PIL import Image, ImageFilter

# Reuse GitHub API helpers from publish_traces.
# Support both direct script execution and package-style imports.
if __package__:
    from ..publish_traces import (
        create_blobs,
        create_commit,
        create_tree,
        get_branch_sha,
        get_tree_sha,
        is_permission_error,
        is_rate_limit_error,
        make_github_request,
        update_branch_ref,
        verify_token_permissions,
    )
else:
    sys.path.insert(0, str(Path(__file__).resolve().parents[1]))
    from publish_traces import (
        create_blobs,
        create_commit,
        create_tree,
        get_branch_sha,
        get_tree_sha,
        is_permission_error,
        is_rate_limit_error,
        make_github_request,
        update_branch_ref,
        verify_token_permissions,
    )

REPO_OWNER = "sgl-project"
REPO_NAME = "ci-data"
BRANCH = "main"
DEFAULT_TARGET_DIR = "diffusion-ci/consistency_gt/sglang_generated"

IMAGE_EXTENSIONS = {".png", ".jpg", ".jpeg", ".webp"}
QUALITY_MAX_SIDE = 256
LOW_DETAIL_STD_THRESHOLD = 0.075
LOW_DETAIL_ENTROPY_THRESHOLD = 0.55
LOW_DETAIL_BLUR_RESIDUAL_THRESHOLD = 0.035
LOW_DETAIL_GRADIENT_P95_THRESHOLD = 0.045
RANDOM_NOISE_CORRELATION_THRESHOLD = 0.55
RANDOM_NOISE_LOW_FREQUENCY_THRESHOLD = 0.20
RANDOM_NOISE_BLUR_RESIDUAL_THRESHOLD = 0.045
OLD_NEW_MIN_SSIM = 0.20
OLD_NEW_MAX_MEAN_ABS_DIFF = 45.0


@dataclass(frozen=True)
class ImageQualityMetrics:
    luminance_std: float
    entropy: float
    blur_residual: float
    gradient_p95: float
    neighbor_correlation: float
    low_frequency_ratio: float


@dataclass(frozen=True)
class OldNewMetrics:
    ssim: float
    mean_abs_diff: float


def collect_images(source_dir, target_dir):
    """Collect image files from source_dir and return list of (repo_path, content) tuples."""
    files = []
    for entry in sorted(os.listdir(source_dir)):
        ext = os.path.splitext(entry)[1].lower()
        if ext not in IMAGE_EXTENSIONS:
            continue
        full_path = os.path.join(source_dir, entry)
        if not os.path.isfile(full_path):
            continue
        with open(full_path, "rb") as f:
            content = f.read()
        repo_path = f"{target_dir}/{entry}"
        files.append((repo_path, content))
    return files


def git_blob_sha(content):
    header = f"blob {len(content)}\0".encode()
    return hashlib.sha1(header + content).hexdigest()


def get_remote_blob_shas(repo_owner, repo_name, target_dir, token):
    return {
        path: item["sha"]
        for path, item in get_remote_image_entries(
            repo_owner, repo_name, target_dir, token
        ).items()
    }


def get_remote_image_entries(repo_owner, repo_name, target_dir, token):
    url = (
        f"https://api.github.com/repos/{repo_owner}/{repo_name}/contents/"
        f"{target_dir}?ref={BRANCH}"
    )
    try:
        response = make_github_request(url, token)
    except HTTPError as e:
        if e.code == 404:
            return {}
        raise
    entries = json.loads(response)
    return {
        item["path"]: item
        for item in entries
        if item.get("type") == "file"
        and "sha" in item
        and os.path.splitext(item["path"])[1].lower() in IMAGE_EXTENSIONS
    }


def filter_changed_files(files, remote_blob_shas):
    return [
        (path, content)
        for path, content in files
        if remote_blob_shas.get(path) != git_blob_sha(content)
    ]


def get_remote_blob_content(repo_owner, repo_name, blob_sha, token):
    url = f"https://api.github.com/repos/{repo_owner}/{repo_name}/git/blobs/{blob_sha}"
    response = make_github_request(url, token)
    blob = json.loads(response)
    if blob.get("encoding") != "base64":
        raise ValueError(
            f"Unexpected blob encoding for {blob_sha}: {blob.get('encoding')}"
        )
    return base64.b64decode(blob["content"])


def _load_quality_image(content):
    with Image.open(io.BytesIO(content)) as image:
        image = image.convert("RGB")
        image.thumbnail((QUALITY_MAX_SIDE, QUALITY_MAX_SIDE), Image.Resampling.BICUBIC)
        return image.copy()


def _image_to_rgb_array(image):
    return np.asarray(image, dtype=np.float32)


def _luminance(rgb):
    return 0.299 * rgb[..., 0] + 0.587 * rgb[..., 1] + 0.114 * rgb[..., 2]


def _neighbor_correlation(luma):
    def corr(a, b):
        a = a.ravel()
        b = b.ravel()
        if a.std() < 1e-6 or b.std() < 1e-6:
            return 1.0
        return float(np.corrcoef(a, b)[0, 1])

    return (corr(luma[:, 1:], luma[:, :-1]) + corr(luma[1:, :], luma[:-1, :])) / 2


def _low_frequency_ratio(luma):
    centered = luma - luma.mean()
    power = np.abs(np.fft.fftshift(np.fft.fft2(centered))) ** 2
    total_power = power.sum()
    if total_power < 1e-12:
        return 0.0

    height, width = luma.shape
    y, x = np.ogrid[:height, :width]
    center_y = height // 2
    center_x = width // 2
    radius = np.sqrt((y - center_y) ** 2 + (x - center_x) ** 2)
    low_frequency_radius = min(height, width) * 0.08
    return float(power[radius <= low_frequency_radius].sum() / total_power)


def compute_image_quality_metrics(content):
    image = _load_quality_image(content)
    rgb = _image_to_rgb_array(image)
    luma = _luminance(rgb) / 255.0

    gradients = np.concatenate(
        [
            np.abs(np.diff(luma, axis=1)).ravel(),
            np.abs(np.diff(luma, axis=0)).ravel(),
        ]
    )
    histogram, _ = np.histogram(luma, bins=32, range=(0, 1))
    probabilities = histogram / histogram.sum()
    nonzero_probabilities = probabilities[probabilities > 0]
    entropy = float(
        -(nonzero_probabilities * np.log2(nonzero_probabilities)).sum() / 5.0
    )
    blurred = _image_to_rgb_array(image.filter(ImageFilter.GaussianBlur(radius=3)))

    return ImageQualityMetrics(
        luminance_std=float(luma.std()),
        entropy=entropy,
        blur_residual=float(np.mean(np.abs(rgb - blurred)) / 255.0),
        gradient_p95=float(np.percentile(gradients, 95)),
        neighbor_correlation=_neighbor_correlation(luma),
        low_frequency_ratio=_low_frequency_ratio(luma),
    )


def get_quality_failure_reasons(metrics):
    reasons = []
    low_detail_static = (
        metrics.luminance_std < LOW_DETAIL_STD_THRESHOLD
        and metrics.entropy < LOW_DETAIL_ENTROPY_THRESHOLD
        and (
            metrics.blur_residual < LOW_DETAIL_BLUR_RESIDUAL_THRESHOLD
            or metrics.gradient_p95 < LOW_DETAIL_GRADIENT_P95_THRESHOLD
        )
    )
    high_frequency_noise = (
        metrics.neighbor_correlation < RANDOM_NOISE_CORRELATION_THRESHOLD
        and metrics.low_frequency_ratio < RANDOM_NOISE_LOW_FREQUENCY_THRESHOLD
        and metrics.blur_residual > RANDOM_NOISE_BLUR_RESIDUAL_THRESHOLD
    )
    if low_detail_static:
        reasons.append("low-contrast low-detail output")
    if high_frequency_noise:
        reasons.append("high-frequency random noise")
    return reasons


def _resize_for_old_new_compare(content, size=None):
    with Image.open(io.BytesIO(content)) as image:
        image = image.convert("RGB")
        if size is None:
            image.thumbnail(
                (QUALITY_MAX_SIDE, QUALITY_MAX_SIDE), Image.Resampling.BICUBIC
            )
        else:
            image = image.resize(size, Image.Resampling.BICUBIC)
        return _image_to_rgb_array(image)


def compute_old_new_metrics(old_content, new_content):
    old_rgb = _resize_for_old_new_compare(old_content)
    new_rgb = _resize_for_old_new_compare(
        new_content, size=(old_rgb.shape[1], old_rgb.shape[0])
    )
    old_luma = _luminance(old_rgb) / 255.0
    new_luma = _luminance(new_rgb) / 255.0

    old_mean = old_luma.mean()
    new_mean = new_luma.mean()
    old_variance = old_luma.var()
    new_variance = new_luma.var()
    covariance = ((old_luma - old_mean) * (new_luma - new_mean)).mean()
    c1 = 0.01**2
    c2 = 0.03**2
    ssim = (
        (2 * old_mean * new_mean + c1)
        * (2 * covariance + c2)
        / ((old_mean**2 + new_mean**2 + c1) * (old_variance + new_variance + c2))
    )

    return OldNewMetrics(
        ssim=float(ssim),
        mean_abs_diff=float(np.abs(old_rgb - new_rgb).mean()),
    )


def _format_quality_metrics(metrics):
    return (
        f"std={metrics.luminance_std:.4f}, entropy={metrics.entropy:.4f}, "
        f"blur_residual={metrics.blur_residual:.4f}, "
        f"gradient_p95={metrics.gradient_p95:.4f}, "
        f"neighbor_corr={metrics.neighbor_correlation:.4f}, "
        f"low_freq={metrics.low_frequency_ratio:.4f}"
    )


def _format_old_new_metrics(metrics):
    return f"ssim={metrics.ssim:.4f}, mean_abs_diff={metrics.mean_abs_diff:.2f}"


def validate_gt_files(files_to_upload, changed_files, remote_image_entries, token):
    failures = []
    for path, content in files_to_upload:
        quality_metrics = compute_image_quality_metrics(content)
        quality_reasons = get_quality_failure_reasons(quality_metrics)
        if quality_reasons:
            failures.append(
                f"{path}: {', '.join(quality_reasons)} "
                f"({_format_quality_metrics(quality_metrics)})"
            )

    for path, content in changed_files:
        remote_entry = remote_image_entries.get(path)
        if not remote_entry:
            continue

        old_content = get_remote_blob_content(
            REPO_OWNER, REPO_NAME, remote_entry["sha"], token
        )
        old_quality_metrics = compute_image_quality_metrics(old_content)
        old_quality_reasons = get_quality_failure_reasons(old_quality_metrics)
        if old_quality_reasons:
            print(
                f"Skipping old/new drift check for {path} because existing GT is "
                f"already suspicious: {', '.join(old_quality_reasons)} "
                f"({_format_quality_metrics(old_quality_metrics)})"
            )
            continue

        old_new_metrics = compute_old_new_metrics(old_content, content)
        if (
            old_new_metrics.ssim < OLD_NEW_MIN_SSIM
            and old_new_metrics.mean_abs_diff > OLD_NEW_MAX_MEAN_ABS_DIFF
        ):
            failures.append(
                f"{path}: changed too far from existing GT "
                f"({_format_old_new_metrics(old_new_metrics)})"
            )

    if not failures:
        print(
            f"GT quality gate passed for {len(files_to_upload)} generated image(s) "
            f"and {len(changed_files)} changed image(s)."
        )
        return

    print("GT quality gate failed; refusing to publish suspicious image updates:")
    for failure in failures:
        print(f"  - {failure}")
    sys.exit(1)


def check_quality(source_dir, target_dir=None):
    target_dir = target_dir or DEFAULT_TARGET_DIR
    token = os.getenv("GITHUB_TOKEN")
    if not token:
        print("Error: GITHUB_TOKEN environment variable not set")
        sys.exit(1)

    files_to_upload = collect_images(source_dir, target_dir)
    if not files_to_upload:
        print(f"No image files found in {source_dir}")
        return

    remote_image_entries = get_remote_image_entries(
        REPO_OWNER, REPO_NAME, target_dir, token
    )
    remote_blob_shas = {
        path: item["sha"] for path, item in remote_image_entries.items()
    }
    changed_files = filter_changed_files(files_to_upload, remote_blob_shas)
    validate_gt_files(files_to_upload, changed_files, remote_image_entries, token)


def publish(source_dir, target_dir=None):
    target_dir = target_dir or DEFAULT_TARGET_DIR
    token = os.getenv("GITHUB_TOKEN")
    if not token:
        print("Error: GITHUB_TOKEN environment variable not set")
        sys.exit(1)

    files_to_upload = collect_images(source_dir, target_dir)
    if not files_to_upload:
        print(f"No image files found in {source_dir}")
        return

    print(
        f"Found {len(files_to_upload)} image(s) to upload to {REPO_OWNER}/{REPO_NAME}/{target_dir}"
    )

    # Verify token
    perm = verify_token_permissions(REPO_OWNER, REPO_NAME, token)
    if perm == "rate_limited":
        print("GitHub API rate-limited, skipping upload.")
        return
    if not perm:
        print("Token permission verification failed.")
        sys.exit(1)

    # Commit with retry (handle concurrent pushes)
    max_retries = 5
    for attempt in range(max_retries):
        try:
            branch_sha = get_branch_sha(REPO_OWNER, REPO_NAME, BRANCH, token)
            tree_sha = get_tree_sha(REPO_OWNER, REPO_NAME, branch_sha, token)
            remote_image_entries = get_remote_image_entries(
                REPO_OWNER, REPO_NAME, target_dir, token
            )
            remote_blob_shas = {
                path: item["sha"] for path, item in remote_image_entries.items()
            }
            changed_files = filter_changed_files(files_to_upload, remote_blob_shas)
            validate_gt_files(
                files_to_upload, changed_files, remote_image_entries, token
            )
            if not changed_files:
                print("No image changes to publish.")
                return

            try:
                tree_items = create_blobs(REPO_OWNER, REPO_NAME, changed_files, token)
            except Exception as e:
                if is_rate_limit_error(e):
                    print("Rate-limited during blob creation, skipping.")
                    return
                if is_permission_error(e):
                    print(
                        f"ERROR: Token lacks write permission to {REPO_OWNER}/{REPO_NAME}. "
                        "Update GH_PAT_FOR_NIGHTLY_CI_DATA with a token that has contents:write."
                    )
                    sys.exit(1)
                raise

            new_tree_sha = create_tree(
                REPO_OWNER, REPO_NAME, tree_sha, tree_items, token
            )
            if new_tree_sha == tree_sha:
                print("No tree changes to publish.")
                return

            commit_msg = f"diffusion-ci: update images in {target_dir} ({len(changed_files)} files) [automated]"
            commit_sha = create_commit(
                REPO_OWNER, REPO_NAME, new_tree_sha, branch_sha, commit_msg, token
            )
            update_branch_ref(REPO_OWNER, REPO_NAME, BRANCH, commit_sha, token)
            print(
                f"Successfully pushed {len(changed_files)} changed images (commit {commit_sha[:10]})"
            )
            return
        except Exception as e:
            if is_rate_limit_error(e):
                print("Rate-limited, skipping.")
                return
            if is_permission_error(e):
                print(f"ERROR: permission denied to {REPO_OWNER}/{REPO_NAME}")
                sys.exit(1)

            retryable = False
            if hasattr(e, "error_body"):
                if "Update is not a fast forward" in e.error_body:
                    retryable = True
                elif "Object does not exist" in e.error_body:
                    retryable = True

            if isinstance(e, HTTPError) and e.code in [422, 500, 502, 503, 504]:
                retryable = True

            if retryable and attempt < max_retries - 1:
                import time

                wait = 2**attempt
                print(
                    f"Attempt {attempt + 1}/{max_retries} failed, retrying in {wait}s..."
                )
                time.sleep(wait)
            else:
                print(f"Failed after {attempt + 1} attempts: {e}")
                raise


def main():
    parser = argparse.ArgumentParser(
        description="Publish diffusion GT images to GitHub"
    )
    parser.add_argument(
        "--source-dir", required=True, help="Directory containing GT images"
    )
    parser.add_argument(
        "--target-dir",
        required=False,
        default=None,
        help=f"Target directory in the remote repo (default: {DEFAULT_TARGET_DIR})",
    )
    parser.add_argument(
        "--check-only",
        action="store_true",
        help="Validate generated GT images without publishing them",
    )
    args = parser.parse_args()
    if args.check_only:
        check_quality(args.source_dir, args.target_dir)
    else:
        publish(args.source_dir, args.target_dir)


if __name__ == "__main__":
    main()