"""
Validates a loaded dataset against its manifest declaration.

DESIGN
------
All functions accept plain numpy arrays and pandas DataFrames — no scanpy or
AnnData imports.  The MCP tool (dataset_validate_manifest_against_data in
dataset_tools.py) handles h5ad loading and calls validate_manifest_against_data.

Five check categories
---------------------
data_level        Detected expression type vs. manifest declaration.
feature_id_type   Spot-check var.index format (gene symbols, Ensembl, etc.).
metadata_columns  Declared columns present in obs; values within allowed set.
group_columns     Each group column exists and has ≥2 usable groups.
default_contrasts Each contrast has ≥3 samples per group after subset_query.

Return structure
----------------
All public functions return a dict with at minimum:
    status  "pass" | "warning" | "error"
    message short human-readable summary

validate_manifest_against_data returns:
    overall_valid   bool
    n_errors        int
    n_warnings      int
    checks          dict of category → result dict
    errors          list[str]   — blocking issues
    warnings        list[str]   — non-blocking issues
    recommendations list[str]   — suggested next steps
"""

from __future__ import annotations

import re
from typing import Any

import numpy as np
import pandas as pd

# ---------------------------------------------------------------------------
# Data-level compatibility map
# (detected_type → set of manifest data_level values that are compatible)
# ---------------------------------------------------------------------------

_COMPAT: dict[str, set[str]] = {
    "raw_counts": {"raw_counts"},
    "log_expression": {"log_expression", "normalized", "tpm", "fpkm", "protein_abundance"},
    "log_ratio_microarray": {"log_ratio", "log_expression", "normalized"},
    "unknown": {
        "raw_counts",
        "log_expression",
        "log_ratio",
        "normalized",
        "tpm",
        "fpkm",
        "protein_abundance",
    },
}

# Feature-ID patterns (applied to a sample of var.index values)
_GENE_SYMBOL_RE = re.compile(r"^[A-Z][A-Z0-9\-\.]{1,19}$")
_ENSEMBL_HUMAN = re.compile(r"^ENSG\d{11}$")
_ENSEMBL_MOUSE = re.compile(r"^ENSMUSG\d{11}$")
_ENTREZ_RE = re.compile(r"^\d+$")

_MANIFEST_TO_DETECTED: dict[str, str] = {
    "gene_symbol": "gene_symbol",
    "ensembl_gene_id": "ensembl",
    "entrez_id": "entrez",
    "probe_id": "probe_id",
    "protein_id": "protein_id",
}


# ---------------------------------------------------------------------------
# Individual checks
# ---------------------------------------------------------------------------


def check_data_level(
    X_flat: np.ndarray,
    declared_data_level: str,
) -> dict[str, Any]:
    """
    Compare manifest-declared data_level against detected expression type.

    Parameters
    ----------
    X_flat:
        1-D numpy array sampled from adata.X (up to ~50 000 values is enough).
    declared_data_level:
        Value of manifest.data_level (e.g. 'log_expression', 'raw_counts').

    Returns
    -------
    dict with: status, declared, detected, compatible, message, details.
    """
    from src.workflows.microarray import classify_expression_data_type

    info = classify_expression_data_type(X_flat)
    detected = info["data_type"]
    compatible = declared_data_level in _COMPAT.get(detected, set())

    if detected == "unknown":
        status = "warning"
        msg = (
            f"Could not confidently classify expression data "
            f"(min={info['value_min']}, max={info['value_max']}, "
            f"is_integer={info['is_integer']}, has_negatives={info['has_negatives']}). "
            f"Manifest declares '{declared_data_level}' — verify manually."
        )
    elif compatible:
        status = "pass"
        msg = (
            f"Detected '{detected}' is compatible with declared data_level='{declared_data_level}'."
        )
    else:
        status = "error"
        msg = (
            f"MISMATCH: manifest declares data_level='{declared_data_level}' "
            f"but data appears to be '{detected}'. "
            f"Check whether the correct data level is declared in the manifest, "
            f"or whether a normalisation step was already applied."
        )

    return {
        "status": status,
        "declared": declared_data_level,
        "detected": detected,
        "compatible": compatible,
        "message": msg,
        "details": {
            k: info[k]
            for k in (
                "is_integer",
                "has_negatives",
                "value_min",
                "value_max",
                "value_mean",
                "value_median",
            )
        },
    }


def check_feature_id_type(
    var_index_sample: list[str],
    declared_type: str,
) -> dict[str, Any]:
    """
    Spot-check var.index values to verify they match the declared feature_id_type.

    Samples up to 200 values and checks the fraction matching each pattern.
    Returns a warning (not error) when confidence is low, since probe ID
    formats vary too much across platforms for a definitive check.

    Parameters
    ----------
    var_index_sample:
        List of feature names from adata.var.index (sample or full list).
    declared_type:
        manifest.feature_id_type value.
    """
    sample = var_index_sample[:200]
    n = len(sample)
    if n == 0:
        return {
            "status": "error",
            "declared": declared_type,
            "detected_pattern": "unknown",
            "message": "var.index is empty — cannot check feature ID type.",
        }

    n_gene = sum(1 for v in sample if _GENE_SYMBOL_RE.match(str(v)))
    n_ensh = sum(1 for v in sample if _ENSEMBL_HUMAN.match(str(v)))
    n_ensm = sum(1 for v in sample if _ENSEMBL_MOUSE.match(str(v)))
    n_entrez = sum(1 for v in sample if _ENTREZ_RE.match(str(v)))

    fracs = {
        "gene_symbol": n_gene / n,
        "ensembl": (n_ensh + n_ensm) / n,
        "entrez": n_entrez / n,
    }

    # Ensembl IDs satisfy the gene-symbol regex too, so check Ensembl first.
    ensembl_frac = (n_ensh + n_ensm) / n
    if ensembl_frac >= 0.5:
        detected_pattern = "ensembl"
        best_frac = ensembl_frac
        best_pattern = "ensembl"
    else:
        best_pattern, best_frac = max(fracs.items(), key=lambda x: x[1])
        detected_pattern = best_pattern if best_frac >= 0.5 else "probe_id_or_unknown"

    expected_pattern = _MANIFEST_TO_DETECTED.get(declared_type, declared_type)
    # probe_id and protein_id can't be detected reliably — treat as pass if
    # the data doesn't strongly look like something else
    if declared_type in ("probe_id", "protein_id"):
        if best_frac > 0.7 and best_pattern in ("gene_symbol", "ensembl", "entrez"):
            status = "warning"
            msg = (
                f"Manifest declares feature_id_type='{declared_type}' but "
                f"{best_frac:.0%} of var.index values look like '{best_pattern}'. "
                f"If probes were already collapsed to gene symbols, "
                f"update feature_id_type to 'gene_symbol'."
            )
        else:
            status = "pass"
            msg = (
                f"feature_id_type='{declared_type}' — pattern not automatically "
                f"verifiable (platform-specific). Sample: {sample[:5]}"
            )
    elif detected_pattern == expected_pattern:
        status = "pass"
        msg = (
            f"var.index looks like '{detected_pattern}' ({best_frac:.0%} match), "
            f"consistent with declared feature_id_type='{declared_type}'."
        )
    elif detected_pattern == "probe_id_or_unknown":
        status = "warning"
        msg = (
            f"Could not confidently classify var.index format "
            f"(best match '{best_pattern}' at only {best_frac:.0%}). "
            f"Manifest declares '{declared_type}'. Sample: {sample[:5]}"
        )
    else:
        status = "warning"
        msg = (
            f"var.index looks like '{detected_pattern}' ({best_frac:.0%} match) "
            f"but manifest declares feature_id_type='{declared_type}'. "
            f"Sample: {sample[:5]}"
        )

    return {
        "status": status,
        "declared": declared_type,
        "detected_pattern": detected_pattern,
        "pattern_fractions": {k: round(v, 3) for k, v in fracs.items()},
        "n_sampled": n,
        "sample_features": sample[:10],
        "message": msg,
    }


def check_metadata_columns(
    obs_df: pd.DataFrame,
    manifest: Any,
) -> dict[str, Any]:
    """
    Verify declared metadata_columns exist in obs and values match allowed set.

    Parameters
    ----------
    obs_df:
        adata.obs as a pandas DataFrame.
    manifest:
        DatasetManifest instance.
    """
    if not manifest.metadata_columns:
        return {
            "status": "pass",
            "message": "No metadata_columns declared in manifest — skipped.",
            "n_checked": 0,
            "columns": {},
        }

    columns: dict[str, Any] = {}
    errors: list[str] = []
    warnings: list[str] = []

    for col_name, col_def in manifest.metadata_columns.items():
        if hasattr(col_def, "role"):
            decoded_col = col_def.decoded_column or col_name
            source_col = col_def.source_column
            allowed = set(col_def.allowed_values)
            missing_vals = set(col_def.missing_values) | {"", "nan", "None"}
        else:
            decoded_col = col_def.get("decoded_column") or col_name
            source_col = col_def.get("source_column")
            allowed = set(col_def.get("allowed_values") or [])
            missing_vals = set(col_def.get("missing_values") or []) | {"", "nan", "None"}

        check_col = decoded_col
        result: dict[str, Any] = {"check_column": check_col, "source_column": source_col}

        if check_col not in obs_df.columns:
            if source_col and source_col in obs_df.columns:
                result["status"] = "warning"
                result["message"] = (
                    f"Source column '{source_col}' present but decoded column "
                    f"'{check_col}' missing — numeric decoder may not have run."
                )
                warnings.append(result["message"])
            else:
                result["status"] = "error"
                result["message"] = f"Column '{check_col}' not found in obs."
                errors.append(result["message"])
            columns[col_name] = result
            continue

        actual_vals = obs_df[check_col].astype(str)
        non_missing = actual_vals[~actual_vals.isin(missing_vals)]
        value_counts = actual_vals.value_counts().to_dict()
        result["value_counts"] = {str(k): int(v) for k, v in value_counts.items()}
        result["n_missing"] = int(actual_vals.isin(missing_vals).sum())
        result["n_annotated"] = int(len(non_missing))

        if allowed:
            unexpected = sorted(set(non_missing.unique()) - allowed)
            result["unexpected_values"] = unexpected
            if unexpected:
                result["status"] = "warning"
                result["message"] = (
                    f"Unexpected values in '{check_col}': {unexpected}. "
                    f"Declared allowed: {sorted(allowed)}"
                )
                warnings.append(result["message"])
            else:
                result["status"] = "pass"
                result["message"] = (
                    f"All non-missing values in '{check_col}' match declared "
                    f"allowed_values ({len(non_missing)} annotated, "
                    f"{result['n_missing']} missing)."
                )
        else:
            result["unexpected_values"] = []
            result["status"] = "pass"
            result["message"] = (
                f"Column '{check_col}' present ({len(actual_vals)} values; "
                f"no allowed_values constraint declared)."
            )

        columns[col_name] = result

    overall = "error" if errors else ("warning" if warnings else "pass")
    return {
        "status": overall,
        "n_checked": len(columns),
        "columns": columns,
        "message": (
            f"{len(errors)} error(s), {len(warnings)} warning(s) "
            f"across {len(columns)} declared metadata columns."
        ),
    }


def check_group_columns(
    obs_df: pd.DataFrame,
    manifest: Any,
    min_group_size: int = 3,
) -> dict[str, Any]:
    """
    Verify each group_column exists in obs and has ≥2 groups with enough samples.

    Parameters
    ----------
    obs_df:
        adata.obs as a pandas DataFrame.
    manifest:
        DatasetManifest instance.
    min_group_size:
        Minimum samples per group (default 3).
    """
    columns: dict[str, Any] = {}
    errors: list[str] = []
    warnings: list[str] = []

    for col in manifest.group_columns:
        if col not in obs_df.columns:
            columns[col] = {
                "status": "error",
                "present": False,
                "message": f"group_column '{col}' not found in obs.",
            }
            errors.append(f"group_column '{col}' missing from obs")
            continue

        vc = obs_df[col].astype(str).value_counts()
        qualifying = {str(k): int(v) for k, v in vc.items() if v >= min_group_size}
        small = {str(k): int(v) for k, v in vc.items() if v < min_group_size}
        n_usable = len(qualifying)

        if n_usable < 2:
            status = "warning"
            msg = (
                f"Column '{col}' has fewer than 2 groups with ≥{min_group_size} "
                f"samples (qualifying: {list(qualifying.keys())})."
            )
            warnings.append(msg)
        else:
            status = "pass"
            msg = f"Column '{col}' has {n_usable} usable groups (≥{min_group_size} samples each)."

        columns[col] = {
            "status": status,
            "present": True,
            "n_unique": int(vc.nunique()),
            "qualifying_groups": qualifying,
            "small_groups": small,
            "message": msg,
        }

    overall = "error" if errors else ("warning" if warnings else "pass")
    return {
        "status": overall,
        "n_checked": len(manifest.group_columns),
        "columns": columns,
        "message": (
            f"{len(errors)} error(s), {len(warnings)} warning(s) "
            f"across {len(manifest.group_columns)} group_column(s)."
        ),
    }


def check_default_contrasts(
    obs_df: pd.DataFrame,
    manifest: Any,
    min_group_size: int = 3,
) -> dict[str, Any]:
    """
    Verify each default_contrast has enough samples in both groups.

    Applies subset_query if declared, then counts test and control samples.

    Parameters
    ----------
    obs_df:
        adata.obs as a pandas DataFrame.
    manifest:
        DatasetManifest instance.
    min_group_size:
        Minimum samples per group for a contrast to be feasible (default 3).
    """
    if not manifest.default_contrasts:
        return {
            "status": "pass",
            "message": "No default_contrasts declared — skipped.",
            "contrasts": [],
        }

    results: list[dict] = []
    errors: list[str] = []
    warnings: list[str] = []

    for i, contrast in enumerate(manifest.default_contrasts):
        factor = contrast.get("design_factor", "")
        test_grp = contrast.get("test_group", "")
        ctrl_grp = contrast.get("control_group", "")
        subset_q = contrast.get("subset_query")
        method = contrast.get("method", "ttest")
        label = f"{test_grp} vs {ctrl_grp} (contrast {i})"

        entry: dict[str, Any] = {
            "design_factor": factor,
            "test_group": test_grp,
            "control_group": ctrl_grp,
            "subset_query": subset_q,
            "method": method,
        }

        # Apply subset_query
        working_df = obs_df
        if subset_q:
            try:
                working_df = obs_df.query(subset_q)
                entry["n_after_subset"] = len(working_df)
            except Exception as exc:
                entry["status"] = "error"
                entry["message"] = f"subset_query failed: {exc}"
                errors.append(entry["message"])
                results.append(entry)
                continue

        if factor not in working_df.columns:
            entry["status"] = "error"
            entry["message"] = (
                f"design_factor '{factor}' not found in obs (after applying subset_query)."
            )
            errors.append(entry["message"])
            results.append(entry)
            continue

        col = working_df[factor].astype(str)
        n_test = int((col == test_grp).sum())
        n_ctrl = int((col == ctrl_grp).sum())
        entry["n_test"] = n_test
        entry["n_control"] = n_ctrl

        if n_test == 0 or n_ctrl == 0:
            entry["status"] = "error"
            entry["message"] = (
                f"{label}: one or both groups have 0 samples "
                f"(test='{test_grp}': {n_test}, control='{ctrl_grp}': {n_ctrl}). "
                f"Check group label spelling and subset_query."
            )
            errors.append(entry["message"])
        elif n_test < min_group_size or n_ctrl < min_group_size:
            entry["status"] = "warning"
            entry["message"] = (
                f"{label}: groups are small "
                f"(test={n_test}, control={n_ctrl}, min={min_group_size}). "
                f"Results may be underpowered."
            )
            warnings.append(entry["message"])
        else:
            entry["status"] = "pass"
            entry["message"] = f"{label}: feasible — test={n_test}, control={n_ctrl}."

        results.append(entry)

    overall = "error" if errors else ("warning" if warnings else "pass")
    return {
        "status": overall,
        "n_checked": len(manifest.default_contrasts),
        "contrasts": results,
        "message": (
            f"{len(errors)} error(s), {len(warnings)} warning(s) "
            f"across {len(manifest.default_contrasts)} contrast(s)."
        ),
    }


# ---------------------------------------------------------------------------
# Top-level validator
# ---------------------------------------------------------------------------


def validate_manifest_against_data(
    X_flat: np.ndarray,
    var_index: list[str],
    obs_df: pd.DataFrame,
    manifest: Any,
) -> dict[str, Any]:
    """
    Run all five checks and return a consolidated validation report.

    Parameters
    ----------
    X_flat:
        1-D numpy array of expression values (sample up to ~50 000 values).
    var_index:
        Feature names from adata.var.index.
    obs_df:
        adata.obs as a pandas DataFrame.
    manifest:
        DatasetManifest instance.

    Returns
    -------
    dict with: overall_valid, n_errors, n_warnings, checks, errors,
               warnings, recommendations.
    """
    checks = {
        "data_level": check_data_level(X_flat, manifest.data_level),
        "feature_id_type": check_feature_id_type(var_index, manifest.feature_id_type),
        "metadata_columns": check_metadata_columns(obs_df, manifest),
        "group_columns": check_group_columns(obs_df, manifest),
        "default_contrasts": check_default_contrasts(obs_df, manifest),
    }

    all_errors: list[str] = []
    all_warnings: list[str] = []

    for name, result in checks.items():
        status = result.get("status", "pass")
        if status == "error":
            all_errors.append(f"[{name}] {result.get('message', '')}")
        elif status == "warning":
            all_warnings.append(f"[{name}] {result.get('message', '')}")

    overall_valid = len(all_errors) == 0

    recommendations: list[str] = []
    if overall_valid and not all_warnings:
        recommendations.append(
            "Manifest is consistent with loaded data. "
            "Proceed with dataset_plan_analysis to start analysis."
        )
    if all_errors:
        recommendations.append(
            "Fix errors before running analysis — they indicate manifest "
            "declarations that contradict the actual data."
        )
    if any("[feature_id_type]" in w for w in all_warnings):
        recommendations.append(
            "Verify feature_id_type by inspecting adata.var.index directly "
            "and updating the manifest if the format has changed."
        )
    if any("[metadata_columns]" in w for w in all_warnings):
        recommendations.append(
            "Review unexpected metadata values — they may indicate new "
            "categories in the data or a stale manifest."
        )
    if any("decoder" in w for w in all_warnings):
        recommendations.append(
            "Re-run decoupler_load_geo_series_matrix with decode_numeric=True "
            "to apply numeric-to-label mapping."
        )

    return {
        "dataset_id": manifest.dataset_id,
        "n_samples": len(obs_df),
        "n_features": len(var_index),
        "overall_valid": overall_valid,
        "n_errors": len(all_errors),
        "n_warnings": len(all_warnings),
        "checks": checks,
        "errors": all_errors,
        "warnings": all_warnings,
        "recommendations": recommendations,
    }