from __future__ import annotations

import argparse
import contextlib
import csv
import json
from collections import defaultdict
from pathlib import Path

import numpy as np


def load_all_reviews(results_dir: Path) -> dict[str, list[dict]]:
    reviews_by_reviewer: dict[str, list[dict]] = {}
    for path in sorted(results_dir.glob("reviews_*.csv")):
        reviewer = path.stem.replace("reviews_", "")
        rows: list[dict] = []
        with open(path) as f:
            for row in csv.DictReader(f):
                rows.append(row)
        if rows:
            reviews_by_reviewer[reviewer] = rows
    return reviews_by_reviewer


def classify_transformation(pair: dict) -> str:
    age_changed = pair.get("source_age") != pair.get("target_age")
    sex_changed = pair.get("source_sex") != pair.get("target_sex")
    if pair.get("_transform_type"):
        return str(pair["_transform_type"])
    if age_changed and sex_changed:
        return "intersectional"
    if age_changed:
        return "age_only"
    if sex_changed:
        return "sex_only"
    return "none"


def build_rating_matrix(
    reviews_by_reviewer: dict[str, list[dict]],
    field: str,
    num_pairs: int,
    value_map: dict[str, float] | None = None,
) -> np.ndarray:
    reviewers = sorted(reviews_by_reviewer.keys())
    matrix = np.full((num_pairs, len(reviewers)), np.nan)
    for j, reviewer in enumerate(reviewers):
        for row in reviews_by_reviewer[reviewer]:
            idx = int(row["pair_index"])
            if idx < num_pairs and row.get(field):
                val = row[field]
                if value_map and val in value_map:
                    matrix[idx, j] = value_map[val]
                else:
                    with contextlib.suppress(ValueError, TypeError):
                        matrix[idx, j] = float(val)
    return matrix


def fleiss_kappa(matrix: np.ndarray, categories: list[int | float]) -> float:
    valid_rows = ~np.any(np.isnan(matrix), axis=1)
    data = matrix[valid_rows]
    n_subjects = data.shape[0]
    n_raters = data.shape[1]

    if n_subjects == 0 or n_raters < 2:
        return float("nan")

    counts = np.zeros((n_subjects, len(categories)))
    for k_idx, k in enumerate(categories):
        counts[:, k_idx] = np.sum(data == k, axis=1)

    p_j = np.sum(counts, axis=0) / (n_subjects * n_raters)
    p_i = (np.sum(counts**2, axis=1) - n_raters) / (n_raters * (n_raters - 1))

    p_bar = np.mean(p_i)
    p_e = np.sum(p_j**2)

    if abs(1.0 - p_e) < 1e-10:
        return 1.0

    return float((p_bar - p_e) / (1.0 - p_e))


def compute_exclusions(
    reviews_by_reviewer: dict[str, list[dict]],
    num_pairs: int,
) -> dict:
    plausible_counts: dict[int, dict[str, int]] = defaultdict(lambda: {"Yes": 0, "No": 0})
    quality_scores: dict[int, list[int]] = defaultdict(list)
    reviewer_counts: dict[int, int] = defaultdict(int)

    for reviews in reviews_by_reviewer.values():
        for row in reviews:
            idx = int(row["pair_index"])
            reviewer_counts[idx] += 1
            p = row.get("clinically_plausible", "Yes")
            if p in ("Yes", "No"):
                plausible_counts[idx][p] += 1
            if row.get("quality_score"):
                quality_scores[idx].append(int(row["quality_score"]))

    excluded_implausible: list[int] = []
    excluded_majority: list[int] = []
    excluded_disputed: list[int] = []

    for idx in range(num_pairs):
        if reviewer_counts[idx] == 0:
            continue

        no_votes = plausible_counts[idx]["No"]
        if no_votes > 0:
            excluded_implausible.append(idx)

        total = reviewer_counts[idx]
        if no_votes > total / 2:
            excluded_majority.append(idx)

        scores = quality_scores.get(idx, [])
        if len(scores) >= 3 and (max(scores) - min(scores)) >= 3 and idx not in excluded_implausible:
            excluded_disputed.append(idx)

    all_excluded = sorted(set(excluded_implausible + excluded_disputed))

    return {
        "implausible_any_rater": excluded_implausible,
        "implausible_majority": excluded_majority,
        "disputed_quality": excluded_disputed,
        "all_excluded": all_excluded,
    }


def compute_stratum_stats(
    pairs: list[dict],
    reviews_by_reviewer: dict[str, list[dict]],
    exclusions: dict,
) -> dict:
    pair_strata: dict[int, str] = {}
    for i, pair in enumerate(pairs):
        pair_strata[i] = classify_transformation(pair)

    all_reviews_by_pair: dict[int, list[dict]] = defaultdict(list)
    for reviews in reviews_by_reviewer.values():
        for row in reviews:
            idx = int(row["pair_index"])
            all_reviews_by_pair[idx].append(row)

    strata = ["age_only", "sex_only", "intersectional"]
    stats: dict[str, dict] = {}

    excluded_set = set(exclusions["all_excluded"])

    for stratum in strata:
        indices = [i for i, s in pair_strata.items() if s == stratum]
        if not indices:
            stats[stratum] = {"total": 0}
            continue

        n_excluded = sum(1 for i in indices if i in excluded_set)
        n_passed = len(indices) - n_excluded

        plausible_yes = 0
        plausible_total = 0
        preserved_yes = 0
        preserved_total = 0
        quality_vals: list[int] = []

        for idx in indices:
            for row in all_reviews_by_pair.get(idx, []):
                if row.get("clinically_plausible") in ("Yes", "No"):
                    plausible_total += 1
                    if row["clinically_plausible"] == "Yes":
                        plausible_yes += 1
                if row.get("pathology_preserved") in ("Yes", "No"):
                    preserved_total += 1
                    if row["pathology_preserved"] == "Yes":
                        preserved_yes += 1
                if row.get("quality_score"):
                    quality_vals.append(int(row["quality_score"]))

        stats[stratum] = {
            "total": len(indices),
            "passed": n_passed,
            "excluded": n_excluded,
            "pass_rate": round(n_passed / len(indices), 3) if indices else 0,
            "plausibility_rate": round(plausible_yes / plausible_total, 3) if plausible_total else None,
            "pathology_preservation_rate": round(preserved_yes / preserved_total, 3) if preserved_total else None,
            "mean_quality": round(float(np.mean(quality_vals)), 2) if quality_vals else None,
            "quality_distribution": {
                str(k): int(np.sum(np.array(quality_vals) == k))
                for k in range(1, 6)
            } if quality_vals else {},
        }

    return stats


def main() -> None:
    parser = argparse.ArgumentParser(description="Aggregate radiologist reviews")
    parser.add_argument("--pairs", type=str, required=True)
    parser.add_argument("--results-dir", type=str, default="results")
    parser.add_argument("--output", type=str, default="validation_report.json")
    args = parser.parse_args()

    with open(args.pairs) as f:
        pairs = json.load(f)
    num_pairs = len(pairs)

    reviews_by_reviewer = load_all_reviews(Path(args.results_dir))
    reviewers = sorted(reviews_by_reviewer.keys())

    if not reviewers:
        print("No review files found.")
        return

    quality_matrix = build_rating_matrix(
        reviews_by_reviewer, "quality_score", num_pairs,
    )
    plausible_matrix = build_rating_matrix(
        reviews_by_reviewer, "clinically_plausible", num_pairs,
        value_map={"Yes": 1.0, "No": 0.0},
    )
    preserved_matrix = build_rating_matrix(
        reviews_by_reviewer, "pathology_preserved", num_pairs,
        value_map={"Yes": 1.0, "No": 0.0, "Uncertain": 0.5},
    )

    kappa_quality = fleiss_kappa(quality_matrix, categories=[1, 2, 3, 4, 5])
    kappa_plausible = fleiss_kappa(plausible_matrix, categories=[0, 1])
    kappa_preserved = fleiss_kappa(preserved_matrix, categories=[0, 0.5, 1])

    exclusions = compute_exclusions(reviews_by_reviewer, num_pairs)
    stratum_stats = compute_stratum_stats(pairs, reviews_by_reviewer, exclusions)

    total_reviewed = sum(len(rows) for rows in reviews_by_reviewer.values())
    per_reviewer: dict[str, dict] = {}
    all_quality: list[int] = []
    for reviewer, rows in reviews_by_reviewer.items():
        scores = [int(r["quality_score"]) for r in rows if r.get("quality_score")]
        n_implausible = sum(1 for r in rows if r.get("clinically_plausible") == "No")
        n_not_preserved = sum(1 for r in rows if r.get("pathology_preserved") == "No")
        per_reviewer[reviewer] = {
            "reviewed": len(rows),
            "mean_quality": round(float(np.mean(scores)), 2) if scores else None,
            "flagged_implausible": n_implausible,
            "flagged_not_preserved": n_not_preserved,
        }
        all_quality.extend(scores)

    quality_dist = {str(k): int(np.sum(np.array(all_quality) == k)) for k in range(1, 6)} if all_quality else {}

    valid_quality = quality_matrix[~np.all(np.isnan(quality_matrix), axis=1)]
    mean_quality = float(np.nanmean(valid_quality)) if valid_quality.size > 0 else None

    report = {
        "num_pairs": num_pairs,
        "num_reviewers": len(reviewers),
        "reviewers": reviewers,
        "total_reviews": total_reviewed,
        "inter_rater_reliability": {
            "fleiss_kappa_quality": round(kappa_quality, 4) if not np.isnan(kappa_quality) else None,
            "fleiss_kappa_plausibility": round(kappa_plausible, 4) if not np.isnan(kappa_plausible) else None,
            "fleiss_kappa_pathology_preservation": round(kappa_preserved, 4) if not np.isnan(kappa_preserved) else None,
        },
        "overall": {
            "mean_quality_score": round(mean_quality, 2) if mean_quality else None,
            "quality_distribution": quality_dist,
            "pass_rate": round(
                (num_pairs - len(exclusions["all_excluded"])) / num_pairs, 3
            ) if num_pairs > 0 else 0,
            "plausibility_rate": round(
                float(np.nanmean(plausible_matrix[~np.all(np.isnan(plausible_matrix), axis=1)])), 3
            ) if plausible_matrix.size > 0 else None,
            "pathology_preservation_rate": round(
                float(np.nanmean(preserved_matrix[~np.all(np.isnan(preserved_matrix), axis=1)])), 3
            ) if preserved_matrix.size > 0 else None,
        },
        "by_transformation_type": stratum_stats,
        "exclusions": {
            "implausible_any_rater": len(exclusions["implausible_any_rater"]),
            "implausible_majority_vote": len(exclusions["implausible_majority"]),
            "disputed_quality": len(exclusions["disputed_quality"]),
            "total_excluded": len(exclusions["all_excluded"]),
            "excluded_pair_indices": exclusions["all_excluded"],
        },
        "per_reviewer": per_reviewer,
    }

    output_path = Path(args.output)
    output_path.parent.mkdir(parents=True, exist_ok=True)
    with open(output_path, "w") as f:
        json.dump(report, f, indent=2)

    exclusion_path = output_path.parent / "exclusion_list.json"
    with open(exclusion_path, "w") as f:
        json.dump({"excluded_pair_indices": exclusions["all_excluded"]}, f, indent=2)

    print(f"Reviewers: {len(reviewers)}")
    print(f"Total reviews: {total_reviewed}")
    print(f"Fleiss kappa (quality): {report['inter_rater_reliability']['fleiss_kappa_quality']}")
    print(f"Fleiss kappa (plausibility): {report['inter_rater_reliability']['fleiss_kappa_plausibility']}")
    print(f"Fleiss kappa (pathology): {report['inter_rater_reliability']['fleiss_kappa_pathology_preservation']}")
    print(f"Overall pass rate: {report['overall']['pass_rate']}")
    print(f"Total excluded: {report['exclusions']['total_excluded']}")
    for stratum, stats in stratum_stats.items():
        if stats.get("total", 0) > 0:
            print(f"  {stratum}: {stats['passed']}/{stats['total']} passed ({stats['pass_rate']})")
    print(f"Report: {output_path}")
    print(f"Exclusion list: {exclusion_path}")


if __name__ == "__main__":
    main()