"""垂直领域分类树：查询分类/元素基础信息与效果得分。"""

import re

from sqlalchemy import text

from app.core.config import settings
from app.db.mysql import SessionLocal

IDENTIFIER_RE = re.compile(r"^[A-Za-z_][A-Za-z0-9_]*$")
DATE_RE = re.compile(r"^\d{8}$")


def _safe_identifier(name: str) -> str:
    if not IDENTIFIER_RE.match(name):
        raise ValueError(f"invalid sql identifier: {name}")
    return name


def _normalize_date(date_value: str | None) -> str | None:
    if not date_value:
        return None
    normalized = date_value.replace("-", "").strip()
    if not normalized:
        return None
    if not DATE_RE.match(normalized):
        raise ValueError("date must be yyyymmdd or yyyy-mm-dd")
    return normalized


def _resolve_partition_dt(dt: str | None) -> str:
    normalized = _normalize_date(dt)
    if normalized:
        return normalized

    category_effect_table = _safe_identifier(settings.vertical_category_effect_table)
    with SessionLocal() as session:
        row = session.execute(
            text(f"SELECT MAX(dt) FROM {category_effect_table}")
        ).first()
    latest = str(row[0] or "").strip() if row else ""
    if not latest:
        raise ValueError("暂无效果数据分区，请先同步垂直领域分类数据")
    return latest


def _is_zero_rov_score(rov_score: object) -> bool:
    if rov_score is None:
        return True
    return float(rov_score) == 0.0


def _build_children_map(categories: list[dict[str, object]]) -> dict[str, list[dict[str, object]]]:
    children_map: dict[str, list[dict[str, object]]] = {}
    for category in categories:
        parent_id = category.get("parent_stable_id")
        if not parent_id:
            continue
        parent_key = str(parent_id)
        children_map.setdefault(parent_key, []).append(category)
    for siblings in children_map.values():
        siblings.sort(key=lambda item: str(item["category_id"]))
    return children_map


def _is_missing_parent(category: dict[str, object], all_ids: set[str]) -> bool:
    parent_id = category.get("parent_stable_id")
    if not parent_id:
        return True
    return str(parent_id) not in all_ids


def _find_root_categories(categories: list[dict[str, object]]) -> list[dict[str, object]]:
    all_ids = {str(item["category_id"]) for item in categories}
    roots = [
        item
        for item in categories
        if _is_missing_parent(item, all_ids) and int(item.get("category_level") or 1) <= 1
    ]
    roots.sort(key=lambda item: str(item["category_id"]))
    return roots


def _find_detached_categories(categories: list[dict[str, object]]) -> list[dict[str, object]]:
    all_ids = {str(item["category_id"]) for item in categories}
    detached = [
        item
        for item in categories
        if _is_missing_parent(item, all_ids) and int(item.get("category_level") or 1) > 1
    ]
    detached.sort(
        key=lambda item: (
            int(item.get("category_level") or 1),
            str(item["category_id"]),
        )
    )
    return detached


def _build_category_depth_map(
    categories: list[dict[str, object]],
    children_map: dict[str, list[dict[str, object]]],
    roots: list[dict[str, object]],
) -> dict[str, int]:
    category_by_id = {str(item["category_id"]): item for item in categories}
    depth_map: dict[str, int] = {}

    def visit(category_id: str, fallback_level: int) -> None:
        if category_id in depth_map:
            return
        category = category_by_id.get(category_id)
        level = category.get("category_level") if category else None
        resolved_level = int(level) if level is not None else fallback_level
        depth_map[category_id] = resolved_level
        for child in children_map.get(category_id, []):
            visit(str(child["category_id"]), resolved_level + 1)

    for root in roots:
        visit(str(root["category_id"]), int(root.get("category_level") or 1))
    for item in _find_detached_categories(categories):
        category_id = str(item["category_id"])
        if category_id not in depth_map:
            visit(category_id, int(item.get("category_level") or 1))
    for category in categories:
        category_id = str(category["category_id"])
        if category_id not in depth_map:
            depth_map[category_id] = int(category.get("category_level") or 1)
    return depth_map


def _get_effective_category_level(
    category: dict[str, object],
    depth_map: dict[str, int],
) -> int:
    level = category.get("category_level")
    if level is not None:
        return int(level)
    return depth_map.get(str(category["category_id"]), 1)


def _build_category_rov_scales_by_level(
    categories: list[dict[str, object]],
) -> dict[str, dict[str, float]]:
    children_map = _build_children_map(categories)
    roots = _find_root_categories(categories)
    depth_map = _build_category_depth_map(categories, children_map, roots)

    scales: dict[int, dict[str, float]] = {}
    for category in categories:
        rov_score = category.get("rov_score")
        if _is_zero_rov_score(rov_score):
            continue
        level = _get_effective_category_level(category, depth_map)
        score = float(rov_score)
        current = scales.get(level)
        if current is None:
            scales[level] = {"min": score, "max": score}
            continue
        current["min"] = min(current["min"], score)
        current["max"] = max(current["max"], score)
    return {str(level): value for level, value in sorted(scales.items())}


def _serialize_category_row(row: object, child_category_ids: set[str]) -> dict[str, object]:
    category_id = str(row["category_id"] or "").strip()
    parent_id = str(row["parent_stable_id"] or "").strip() or None
    if parent_id:
        child_category_ids.add(parent_id)
    rov_score = row["rov_score"]
    return {
        "category_id": category_id,
        "parent_stable_id": parent_id,
        "category_name": row["category_name"],
        "category_level": row["category_level"],
        "vid_count": row["vid_count"],
        "rov_score": float(rov_score) if rov_score is not None else None,
        "is_leaf": False,
    }


def _query_element_counts_by_category(
    session: object,
    element_base_table: str,
    element_effect_table: str,
    partition_dt: str,
) -> tuple[dict[str, dict[str, int]], int]:
    rows = session.execute(
        text(
            f"""
            SELECT
                b.stable_id,
                COUNT(*) AS total,
                SUM(
                    CASE
                        WHEN e.rov_score IS NULL OR e.rov_score = 0 THEN 1
                        ELSE 0
                    END
                ) AS invalid
            FROM {element_base_table} b
            LEFT JOIN {element_effect_table} e
                ON b.element_id = e.element_id
                AND e.dt = :dt
            WHERE b.stable_id IS NOT NULL
                AND TRIM(b.stable_id) <> ''
            GROUP BY b.stable_id
            """
        ),
        {"dt": partition_dt},
    ).mappings().all()

    counts_by_category: dict[str, dict[str, int]] = {}
    invalid_total = 0
    for row in rows:
        category_id = str(row["stable_id"] or "").strip()
        if not category_id:
            continue
        total = int(row["total"] or 0)
        invalid = int(row["invalid"] or 0)
        valid = max(total - invalid, 0)
        counts_by_category[category_id] = {"total": total, "valid": valid}
        invalid_total += invalid
    return counts_by_category, invalid_total


def _query_global_element_rov_scale(
    session: object,
    element_effect_table: str,
    partition_dt: str,
) -> dict[str, float]:
    row = session.execute(
        text(
            f"""
            SELECT
                MIN(rov_score) AS min_rov_score,
                MAX(rov_score) AS max_rov_score
            FROM {element_effect_table}
            WHERE dt = :dt
                AND rov_score IS NOT NULL
                AND rov_score <> 0
            """
        ),
        {"dt": partition_dt},
    ).mappings().first()
    if not row or row["min_rov_score"] is None or row["max_rov_score"] is None:
        return {"min": 0.0, "max": 0.0}
    return {
        "min": float(row["min_rov_score"]),
        "max": float(row["max_rov_score"]),
    }


def query_available_dates() -> list[str]:
    category_effect_table = _safe_identifier(settings.vertical_category_effect_table)
    with SessionLocal() as session:
        rows = session.execute(
            text(
                f"""
                SELECT DISTINCT dt
                FROM {category_effect_table}
                ORDER BY dt DESC
                LIMIT 366
                """
            )
        ).all()
    return [str(row[0]) for row in rows if row[0]]


def query_vertical_category_tree(dt: str | None = None) -> dict[str, object]:
    partition_dt = _resolve_partition_dt(dt)

    category_base_table = _safe_identifier(settings.vertical_category_base_table)
    category_effect_table = _safe_identifier(settings.vertical_category_effect_table)
    element_base_table = _safe_identifier(settings.substance_element_base_table)
    element_effect_table = _safe_identifier(settings.substance_element_effect_table)

    category_sql = text(
        f"""
        SELECT
            b.category_id,
            b.parent_stable_id,
            b.category_name,
            b.category_level,
            e.vid_count,
            e.rov_score
        FROM {category_base_table} b
        LEFT JOIN {category_effect_table} e
            ON b.category_id = e.category_id
            AND e.dt = :dt
        ORDER BY b.category_level ASC, b.category_id ASC
        """
    )

    with SessionLocal() as session:
        category_rows = session.execute(category_sql, {"dt": partition_dt}).mappings().all()
        element_counts_by_category, element_invalid_count = _query_element_counts_by_category(
            session,
            element_base_table,
            element_effect_table,
            partition_dt,
        )
        element_rov_scale = _query_global_element_rov_scale(
            session,
            element_effect_table,
            partition_dt,
        )

    categories: list[dict[str, object]] = []
    child_category_ids: set[str] = set()
    for row in category_rows:
        categories.append(_serialize_category_row(row, child_category_ids))

    for item in categories:
        item["is_leaf"] = item["category_id"] not in child_category_ids

    return {
        "dt": partition_dt,
        "available_dates": query_available_dates(),
        "element_invalid_count": element_invalid_count,
        "element_counts_by_category": element_counts_by_category,
        "rov_scales": {
            "category_by_level": _build_category_rov_scales_by_level(categories),
            "element": element_rov_scale,
        },
        "categories": categories,
    }


def query_category_elements(category_id: str, dt: str | None = None) -> dict[str, object]:
    normalized_category_id = category_id.strip()
    if not normalized_category_id:
        raise ValueError("category_id is required")

    partition_dt = _resolve_partition_dt(dt)

    element_base_table = _safe_identifier(settings.substance_element_base_table)
    element_effect_table = _safe_identifier(settings.substance_element_effect_table)

    element_sql = text(
        f"""
        SELECT
            b.element_id,
            b.stable_id,
            b.element_name,
            e.vid_count,
            e.rov_score
        FROM {element_base_table} b
        LEFT JOIN {element_effect_table} e
            ON b.element_id = e.element_id
            AND e.dt = :dt
        WHERE b.stable_id = :category_id
        ORDER BY b.element_id ASC
        """
    )

    with SessionLocal() as session:
        element_rows = session.execute(
            element_sql,
            {"dt": partition_dt, "category_id": normalized_category_id},
        ).mappings().all()
        rov_scale = _query_global_element_rov_scale(session, element_effect_table, partition_dt)

    elements: list[dict[str, object]] = []
    for row in element_rows:
        rov_score = row["rov_score"]
        elements.append(
            {
                "element_id": str(row["element_id"] or "").strip(),
                "stable_id": str(row["stable_id"] or "").strip() or None,
                "element_name": row["element_name"],
                "vid_count": row["vid_count"],
                "rov_score": float(rov_score) if rov_score is not None else None,
            }
        )

    return {
        "dt": partition_dt,
        "category_id": normalized_category_id,
        "elements": elements,
        "rov_scales": {
            "element": rov_scale,
        },
    }