from __future__ import annotations

import json
import os
import re
from collections import OrderedDict
from datetime import datetime
from typing import Any, Dict, List, Optional, Tuple

import pg8000.dbapi as pg

# Separate configuration so legacy fs_law_risk integration keeps using PG_*
LIC_DEFAULT_DB = "licensing_risks"


ARTICLE_HEADING_RE = re.compile(r"(?m)^(第[一二三四五六七八九十百零0-9]+条)")
ARTICLE_TOKEN_RE = re.compile(r"(?<!\*)(第[一二三四五六七八九十百零0-9]+条)(?!\*)")
ARTICLE_NEWLINE_RE = re.compile(r"(?<!^)(?<!\n)(\*\*第[一二三四五六七八九十百零0-9]+条\*\*)")
CN_ENUM_INLINE_RE = re.compile(r"([；;:：。．])[ \t]*（([一二三四五六七八九十百零]+)）")
CN_ENUM_LINE_RE = re.compile(r"(?m)^\s*（([一二三四五六七八九十百零]+)）")
ARABIC_ENUM_INLINE_RE = re.compile(r"([；;:：。．，,])[ \t]*(\d+\.)")
ARABIC_ENUM_LINE_RE = re.compile(r"(?m)^\s*(\d+)\.")
NESTED_ENUM_INLINE_RE = re.compile(r"([；;:：。．])[ \t]*（(\d+)）")
NESTED_ENUM_LINE_RE = re.compile(r"(?m)^\s*（(\d+)）")
COLON_NEWLINE_RE = re.compile(r"：\s*\n")
TRAILING_SPACE_RE = re.compile(r"[ \t]+\n")
EXTRA_NEWLINES_RE = re.compile(r"\n{3,}")


def _format_summary_markdown(summary: str) -> str:
    """Render Chinese legal excerpts as Markdown-friendly text."""
    if not summary:
        return ""

    text = summary.replace("\r\n", "\n").strip()
    if not text:
        return ""

    text = ARTICLE_HEADING_RE.sub(lambda m: f"**{m.group(1)}**", text)
    text = CN_ENUM_INLINE_RE.sub(lambda m: f"{m.group(1)}\n- （{m.group(2)}） ", text)
    text = CN_ENUM_LINE_RE.sub(lambda m: f"- （{m.group(1)}） ", text)
    text = ARABIC_ENUM_INLINE_RE.sub(lambda m: f"{m.group(1)}\n  {m.group(2)}", text)
    text = ARABIC_ENUM_LINE_RE.sub(lambda m: f"  {m.group(1)}.", text)
    text = NESTED_ENUM_INLINE_RE.sub(lambda m: f"{m.group(1)}\n    - （{m.group(2)}）", text)
    text = NESTED_ENUM_LINE_RE.sub(lambda m: f"    - （{m.group(1)}）", text)
    text = ARTICLE_TOKEN_RE.sub(lambda m: f"**{m.group(1)}**", text)
    text = ARTICLE_NEWLINE_RE.sub(lambda m: f"\n{m.group(1)}", text)
    text = COLON_NEWLINE_RE.sub("：\n", text)
    text = EXTRA_NEWLINES_RE.sub("\n\n", text)
    text = TRAILING_SPACE_RE.sub("\n", text)
    text = re.sub(r"\n\s+\n", "\n\n", text)
    return text.strip()


def _lic_pg_conn(autocommit: bool = False) -> pg.Connection:
    host = os.getenv("LIC_PG_HOST", "172.24.240.1")
    port = int(os.getenv("LIC_PG_PORT", os.getenv("PG_PORT", "5432")))
    user = os.getenv("LIC_PG_USER", os.getenv("PG_USER", "postgres"))
    password = os.getenv("LIC_PG_PASSWORD", "")
    database = os.getenv("LIC_PG_DATABASE", LIC_DEFAULT_DB)
    conn = pg.connect(host=host, port=port, user=user, password=password, database=database)
    conn.autocommit = autocommit
    return conn


def list_region_theme_options() -> List[Dict[str, str]]:
    """Return all region-theme pairs usable for LLM selection."""
    sql = """
        SELECT
            rt.region_id,
            r.name AS region_name,
            rt.theme_id,
            t.name AS theme_name
        FROM region_themes rt
        JOIN regions r ON r.id = rt.region_id
        JOIN themes t ON t.id = rt.theme_id
        ORDER BY r.name, t.name
    """
    out: List[Dict[str, str]] = []
    with _lic_pg_conn() as conn:
        cur = conn.cursor()
        cur.execute(sql)
        for region_id, region_name, theme_id, theme_name in cur.fetchall():
            rid = str(region_id)
            tid = str(theme_id)
            out.append(
                {
                    "option_id": f"{rid}:{tid}",
                    "region_id": rid,
                    "region_name": str(region_name),
                    "theme_id": tid,
                    "theme_name": str(theme_name),
                    "display_name": f"{region_name} · {theme_name}",
                }
            )
    return out


def load_business_scopes(region_id: str) -> List[Dict[str, str]]:
    """List business scopes bound to a region."""
    sql = """
        SELECT bs.id, bs.description
        FROM region_scopes rs
        JOIN business_scopes bs ON bs.id = rs.scope_id
        WHERE rs.region_id = %s
        ORDER BY bs.description
    """
    scopes: List[Dict[str, str]] = []
    with _lic_pg_conn() as conn:
        cur = conn.cursor()
        cur.execute(sql, (region_id,))
        for scope_id, description in cur.fetchall():
            scopes.append({"id": str(scope_id), "description": str(description)})
    return scopes


def list_permits_for_region(region: str) -> List[Dict[str, str]]:
    """Return all permits available within a region (accepts id or name)."""
    sql = """
        SELECT DISTINCT p.id, p.name
        FROM region_theme_permits rtp
        JOIN permits p ON p.id = rtp.permit_id
        JOIN regions r ON r.id = rtp.region_id
        WHERE rtp.region_id::text = %s OR LOWER(r.name) = LOWER(%s)
        ORDER BY p.name
    """
    permits: List[Dict[str, str]] = []
    with _lic_pg_conn() as conn:
        cur = conn.cursor()
        cur.execute(sql, (region, region))
        for permit_id, permit_name in cur.fetchall():
            permits.append({"id": str(permit_id), "name": str(permit_name)})
    return permits


def _load_permit_scopes_for_region(
    conn: pg.Connection, region_id: str, permit_ids: List[str]
) -> Dict[str, List[Dict[str, str]]]:
    """Return mapping of permit_id -> business scopes for that permit within region."""
    scope_map: Dict[str, List[Dict[str, str]]] = {pid: [] for pid in permit_ids}
    if not permit_ids:
        return scope_map

    sql = """
        SELECT rps.permit_id, bs.id, bs.description
        FROM region_permit_scopes rps
        JOIN business_scopes bs ON bs.id = rps.scope_id
        WHERE rps.region_id = %s
        ORDER BY rps.permit_id, bs.description
    """
    cur = conn.cursor()
    try:
        cur.execute(sql, (region_id,))
    except pg.ProgrammingError as exc:
        # 42P01 => undefined_table; allow fallback when migration not yet applied.
        sqlstate = getattr(exc, "sqlstate", "")
        if sqlstate == "42P01":
            return scope_map
        raise

    for permit_id, scope_id, description in cur.fetchall():
        pid = str(permit_id)
        if pid not in scope_map:
            continue
        scope_map[pid].append({"id": str(scope_id), "description": str(description)})
    return scope_map


def load_permits_and_risks(
    region_id: str, theme_id: str, permit_id: Optional[str] = None
) -> List[Dict[str, object]]:
    """Return permits with attached risk entries for a region-theme pair."""
    sql = """
        SELECT
            p.id AS permit_id,
            p.name AS permit_name,
            rk.id AS risk_id,
            rk.risk_content,
            rk.legal_basis,
            rk.document_no,
            rk.summary,
            rpd.permit_status,
            rpd.subitem_summary,
            rpd.responsible_contact,
            rpd.jurisdiction_scope
        FROM region_theme_permits rtp
        JOIN permits p ON p.id = rtp.permit_id
        LEFT JOIN region_permit_risks rpr
               ON rpr.region_id = rtp.region_id
              AND rpr.permit_id = rtp.permit_id
        LEFT JOIN risks rk ON rk.id = rpr.risk_id
        LEFT JOIN region_permit_details rpd
               ON rpd.region_id = rtp.region_id
              AND rpd.permit_id = rtp.permit_id
        WHERE rtp.region_id = %s AND rtp.theme_id = %s
    """
    params: List[Any] = [region_id, theme_id]
    if permit_id is not None:
        sql += " AND rtp.permit_id = %s"
        params.append(permit_id)

    sql += """
        ORDER BY p.name, rk.risk_content
    """
    permits: Dict[str, Dict[str, object]] = {}
    with _lic_pg_conn() as conn:
        cur = conn.cursor()
        cur.execute(sql, tuple(params))
        for row in cur.fetchall():
            (
                permit_id,
                permit_name,
                risk_id,
                risk_content,
                legal_basis,
                document_no,
                summary,
                permit_status,
                subitem_summary,
                responsible_contact,
                jurisdiction_scope,
            ) = row
            pid = str(permit_id)
            entry = permits.setdefault(
                pid,
                {
                    "id": pid,
                    "name": str(permit_name),
                    "business_scopes": [],
                    "risks": [],
                    "permit_status": None,
                    "subitem_summary": None,
                    "responsible_contact": None,
                    "jurisdiction_scope": None,
                },
            )
            if entry["permit_status"] is None and permit_status:
                entry["permit_status"] = permit_status.strip() or None
            if entry["subitem_summary"] is None and subitem_summary:
                entry["subitem_summary"] = subitem_summary.strip() or None
            if entry["responsible_contact"] is None and responsible_contact:
                entry["responsible_contact"] = responsible_contact.strip() or None
            if entry["jurisdiction_scope"] is None and jurisdiction_scope:
                entry["jurisdiction_scope"] = jurisdiction_scope.strip() or None
            if risk_id is not None:
                summary_markdown = _format_summary_markdown(summary or "")
                entry["risks"].append(
                    {
                        "id": str(risk_id),
                        "risk_content": risk_content or "",
                        "legal_basis": legal_basis or "",
                        "document_no": document_no or "",
                        "summary": summary_markdown,
                    }
                )

        permit_ids = list(permits.keys())
        scope_map = _load_permit_scopes_for_region(conn, region_id, permit_ids)
        for pid in permit_ids:
            permits[pid]["business_scopes"] = scope_map.get(pid, [])
    return list(permits.values())


def find_permit_contexts_by_name(permit_name: str) -> List[Dict[str, str]]:
    """Return region/theme contexts for permits with an exact name match."""
    if not permit_name:
        return []

    sql = """
        SELECT
            rtp.region_id,
            r.name AS region_name,
            rtp.theme_id,
            t.name AS theme_name,
            p.id AS permit_id,
            p.name AS permit_name
        FROM region_theme_permits rtp
        JOIN permits p ON p.id = rtp.permit_id
        JOIN regions r ON r.id = rtp.region_id
        JOIN themes t ON t.id = rtp.theme_id
        WHERE p.name = %s
        ORDER BY r.name, t.name
    """
    ordered: OrderedDict[Tuple[str, str], Dict[str, str]] = OrderedDict()
    with _lic_pg_conn() as conn:
        cur = conn.cursor()
        cur.execute(sql, (permit_name,))
        for row in cur.fetchall():
            region_id, region_name, theme_id, theme_name, permit_id, canonical_name = row
            rid = str(region_id)
            pid = str(permit_id)
            key = (rid, pid)
            if key in ordered:
                continue
            ordered[key] = {
                "region_id": rid,
                "region_name": str(region_name),
                "theme_id": str(theme_id),
                "theme_name": str(theme_name),
                "permit_id": pid,
                "permit_name": str(canonical_name),
            }
    return list(ordered.values())


def load_theme_payload(region_id: str, theme_id: str) -> Dict[str, object]:
    """Assemble full data bundle for a region-theme selection."""
    info_sql = """
        SELECT r.id, r.name, t.id, t.name
        FROM regions r
        JOIN region_themes rt ON rt.region_id = r.id
        JOIN themes t ON t.id = rt.theme_id
        WHERE r.id = %s AND t.id = %s
        LIMIT 1
    """
    with _lic_pg_conn() as conn:
        cur = conn.cursor()
        cur.execute(info_sql, (region_id, theme_id))
        row = cur.fetchone()
        if not row:
            raise ValueError("Region/theme combination not found")
        region_uuid, region_name, theme_uuid, theme_name = row

    permits = load_permits_and_risks(region_id, theme_id)
    return {
        "region": {"id": str(region_uuid), "name": str(region_name)},
        "theme": {"id": str(theme_uuid), "name": str(theme_name)},
        "permits": permits,
    }


def _get_checkpoints_dir() -> str:
    """Get the directory for storing checkpoint files."""
    base_dir = os.path.join(os.path.dirname(os.path.dirname(os.path.dirname(__file__))), "data")
    checkpoints_dir = os.path.join(base_dir, "checkpoints")
    os.makedirs(checkpoints_dir, exist_ok=True)
    return checkpoints_dir


def _get_all_tables() -> List[str]:
    """Get list of all tables in the licensing_risks database."""
    sql = """
        SELECT table_name
        FROM information_schema.tables
        WHERE table_schema = 'public'
        AND table_type = 'BASE TABLE'
        ORDER BY table_name
    """
    with _lic_pg_conn() as conn:
        cur = conn.cursor()
        cur.execute(sql)
        return [row[0] for row in cur.fetchall()]


def _backup_table(conn: pg.Connection, table_name: str) -> Tuple[List[Dict[str, Any]], int]:
    """Backup a single table and return its data and row count."""
    sql = f"SELECT * FROM {table_name}"
    cur = conn.cursor()
    cur.execute(sql)

    rows = cur.fetchall()
    colnames = [desc[0] for desc in cur.description]

    data = []
    for row in rows:
        row_dict = {}
        for i, col in enumerate(colnames):
            value = row[i]
            if value is not None:
                # Convert UUID and other non-serializable types to strings
                if hasattr(value, 'isoformat'):  # UUID, datetime, etc.
                    row_dict[col] = str(value)
                else:
                    row_dict[col] = value
        data.append(row_dict)

    return data, len(data)


def _restore_table(conn: pg.Connection, table_name: str, data: List[Dict[str, Any]]) -> int:
    """Restore a table from backup data. Returns number of rows restored."""
    if not data:
        return 0

    conn.autocommit = False
    try:
        cur = conn.cursor()

        delete_sql = f"DELETE FROM {table_name}"
        cur.execute(delete_sql)

        if data:
            columns = list(data[0].keys())
            placeholders = ", ".join(["%s"] * len(columns))
            insert_sql = f"INSERT INTO {table_name} ({', '.join(columns)}) VALUES ({placeholders})"

            for row in data:
                values = [row.get(col) for col in columns]
                cur.execute(insert_sql, values)

        conn.commit()
        return len(data)
    except Exception as e:
        conn.rollback()
        raise e
    finally:
        conn.autocommit = False


def create_checkpoint(description: str = "") -> Dict[str, Any]:
    """Create a checkpoint by backing up all tables."""
    timestamp = datetime.now().strftime("%Y%m%d_%H%M%S")
    checkpoint_id = f"checkpoint_{timestamp}"

    tables = _get_all_tables()
    checkpoint_data = {
        "checkpoint_id": checkpoint_id,
        "timestamp": timestamp,
        "description": description,
        "tables": {}
    }

    total_rows = 0
    table_counts = {}

    with _lic_pg_conn() as conn:
        for table in tables:
            data, row_count = _backup_table(conn, table)
            checkpoint_data["tables"][table] = data
            table_counts[table] = row_count
            total_rows += row_count

    checkpoint_data["table_counts"] = table_counts
    checkpoint_data["total_rows"] = total_rows

    checkpoints_dir = _get_checkpoints_dir()
    checkpoint_file = os.path.join(checkpoints_dir, f"{checkpoint_id}.json")

    def json_serializer(obj):
        """Convert non-JSON serializable objects to strings."""
        try:
            import uuid
            if isinstance(obj, uuid.UUID):
                return str(obj)
        except ImportError:
            pass

        if hasattr(obj, 'isoformat'):
            return str(obj)
        raise TypeError(f"Object of type {type(obj)} is not JSON serializable")

    with open(checkpoint_file, "w", encoding="utf-8") as f:
        json.dump(checkpoint_data, f, ensure_ascii=False, indent=2, default=json_serializer)

    return {
        "checkpoint_id": checkpoint_id,
        "timestamp": timestamp,
        "description": description,
        "total_rows": total_rows,
        "table_counts": table_counts
    }


def list_checkpoints() -> List[Dict[str, Any]]:
    """List all available checkpoints."""
    checkpoints_dir = _get_checkpoints_dir()
    checkpoints = []

    if not os.path.exists(checkpoints_dir):
        return checkpoints

    for filename in os.listdir(checkpoints_dir):
        if filename.endswith(".json"):
            filepath = os.path.join(checkpoints_dir, filename)
            try:
                with open(filepath, "r", encoding="utf-8") as f:
                    data = json.load(f)
                    checkpoints.append({
                        "checkpoint_id": data["checkpoint_id"],
                        "timestamp": data["timestamp"],
                        "description": data.get("description", ""),
                        "total_rows": data.get("total_rows", 0),
                        "table_counts": data.get("table_counts", {}),
                        "filename": filename
                    })
            except Exception as e:
                print(f"Error reading checkpoint {filename}: {e}")

    return sorted(checkpoints, key=lambda x: x["timestamp"], reverse=True)


def restore_checkpoint(checkpoint_id: str) -> Dict[str, Any]:
    """Restore database from a checkpoint. This is a destructive operation!"""
    checkpoints_dir = _get_checkpoints_dir()
    checkpoint_file = os.path.join(checkpoints_dir, f"{checkpoint_id}.json")

    if not os.path.exists(checkpoint_file):
        raise ValueError(f"Checkpoint {checkpoint_id} not found")

    with open(checkpoint_file, "r", encoding="utf-8") as f:
        checkpoint_data = json.load(f)

    tables = checkpoint_data.get("tables", {})
    restore_summary = {
        "checkpoint_id": checkpoint_id,
        "tables_restored": 0,
        "total_rows_restored": 0,
        "table_details": {}
    }

    with _lic_pg_conn(autocommit=False) as conn:
        try:
            for table_name, data in tables.items():
                rows_restored = _restore_table(conn, table_name, data)
                restore_summary["tables_restored"] += 1
                restore_summary["total_rows_restored"] += rows_restored
                restore_summary["table_details"][table_name] = rows_restored

            conn.commit()
        except Exception as e:
            conn.rollback()
            raise e

    return restore_summary


def delete_checkpoint(checkpoint_id: str) -> bool:
    """Delete a checkpoint file."""
    checkpoints_dir = _get_checkpoints_dir()
    checkpoint_file = os.path.join(checkpoints_dir, f"{checkpoint_id}.json")

    if os.path.exists(checkpoint_file):
        os.remove(checkpoint_file)
        return True
    return False