import os
import re
import threading
import shutil
import sys
from typing import Dict, List, Any

class FalkorDBMock:
    """A robust in-memory graph mock for local development."""
    def __init__(self):
        self.nodes = [] # List of dicts with 'labels', 'properties'
        self.vectors = {} # node_index -> vector
        self.lock = threading.Lock()

    def _resolve_params(self, cypher: str, params: Dict = None) -> str:
        if not params:
            return cypher
        # Sort keys by length descending to avoid partial replacement issues ($id vs $id_2)
        for k in sorted(params.keys(), key=len, reverse=True):
            v = params[k]
            placeholder = f"${k}"
            # If it's a vector, we don't replace it in the string (it's too large)
            if isinstance(v, list) and len(v) > 0 and isinstance(v[0], float):
                continue
            replacement = f"'{v}'" if isinstance(v, str) else str(v)
            cypher = cypher.replace(placeholder, replacement)
        return cypher

    def query(self, cypher: str, params: Dict = None):
        with self.lock:
            cypher = self._resolve_params(cypher, params)
            cypher_upper = cypher.upper()

            # 0. Handle Vector Index Creation
            if "CALL DB.IDX.VECTOR.CREATE" in cypher_upper:
                return []

            # 1. Handle Vector Search
            if "CALL DB.IDX.VECTOR.QUERY" in cypher_upper:
                label_filter = "Rule" if "'RULES'" in cypher_upper or "'RULE'" in cypher_upper else "Memory" if "'MEMORIES'" in cypher_upper or "'MEMORY'" in cypher_upper else None
                results = []
                for n in self.nodes:
                    if not label_filter or label_filter in n['labels']:
                        results.append([
                            n['properties'].get('name', n['properties'].get('content', 'Unknown')),
                            n['properties'].get('description', n['properties'].get('summary', '')),
                            0.9
                        ])
                return results

            # 2. Handle CREATE / MERGE
            if "CREATE" in cypher_upper or "MERGE" in cypher_upper:
                # Multi-clause support (crude)
                clauses = re.split(r"(CREATE|MERGE)", cypher, flags=re.IGNORECASE)[1:]
                for i in range(0, len(clauses), 2):
                    op = clauses[i].upper()
                    content = clauses[i+1]
                    label_match = re.search(r":(\w+)", content)
                    label = label_match.group(1) if label_match else "Unknown"
                    props = self._parse_props(content)
                    self.nodes.append({"labels": [label], "properties": props})
                return []

            # 3. Handle MATCH / SET / RETURN
            if "MATCH" in cypher_upper:
                # Find matching nodes
                matched_nodes = []
                # Improved regex to handle (n), (n:Label), and (n {props})
                match_clauses = re.findall(r"MATCH\s+\((\w+)(?::(\w+))?(?:\s*\{([^}]+)\})?\)", cypher, flags=re.IGNORECASE | re.DOTALL)

                for var, label, props_str in match_clauses:
                    target_props = self._parse_props(f"{{{props_str}}}") if props_str else {}
                    for node in self.nodes:
                        if not label or label in node['labels']:
                            match = True
                            for k, v in target_props.items():
                                if node['properties'].get(k) != v:
                                    match = False
                                    break
                            if match:
                                # Basic WHERE label support: WHERE n:Player OR n:Location
                                where_match = re.search(rf"WHERE\s+(.+?)(?=\s+SET|\s+MATCH|\s+MERGE|\s+CREATE|\s+RETURN|$)", cypher, flags=re.IGNORECASE | re.DOTALL)
                                if where_match:
                                    where_clause = where_match.group(1)
                                    allowed_labels = re.findall(rf"{var}:(\w+)", where_clause)
                                    if allowed_labels:
                                        if not any(l in node['labels'] for l in allowed_labels):
                                            continue
                                matched_nodes.append(node)

                # Handle SET
                if "SET" in cypher_upper:
                    set_clauses = re.findall(r"SET\s+(\w+)\.(\w+)\s*=\s*(.+?)(?=\s+SET|\s+MATCH|\s+MERGE|\s+CREATE|\s+RETURN|$)", cypher, flags=re.IGNORECASE)
                    for var, prop, val_expr in set_clauses:
                        val_expr = val_expr.strip().strip("'\"")
                        for node in matched_nodes:
                            # Crude numeric evaluation
                            if val_expr.replace('.','',1).isdigit() or (val_expr.startswith('-') and val_expr[1:].replace('.','',1).isdigit()):
                                node['properties'][prop] = float(val_expr) if '.' in val_expr else int(val_expr)
                            else:
                                node['properties'][prop] = val_expr
                    return []

                # Handle DELETE
                if "DELETE" in cypher_upper:
                    # Very crude: delete all matched nodes
                    for node in matched_nodes:
                        if node in self.nodes:
                            self.nodes.remove(node)
                    return []

                # Handle RETURN
                return_match = re.search(r"RETURN\s+(.+)$", cypher, flags=re.IGNORECASE | re.DOTALL)
                if return_match:
                    ret_expr = return_match.group(1).strip()
                    results = []
                    for node in matched_nodes:
                        row = []
                        for item in ret_expr.split(","):
                            item = item.strip()
                            # Handle labels(n)[0] as type
                            if "LABELS(" in item.upper():
                                row.append(node['labels'][0])
                            elif "." in item:
                                # Handle n.prop
                                prop = item.split(".")[1]
                                # Remove 'AS alias' if present
                                prop = prop.split(" ")[0]
                                row.append(node['properties'].get(prop))
                            else:
                                row.append(node['properties'])
                        results.append(row)
                    return results

            return None

    def _parse_props(self, s: str) -> Dict:
        props = {}
        # String props
        matches = re.findall(r"(\w+):\s*['\"]([^'\"]+)['\"]", s)
        for k, v in matches: props[k] = v
        # Number props (handling negative numbers)
        num_matches = re.findall(r"(\w+):\s*(-?\d+\.?\d*)", s)
        for k, v in num_matches: props[k] = float(v) if '.' in v else int(v)
        return props

    def dump(self, path: str):
        import pickle
        with open(path, "wb") as f:
            pickle.dump({"nodes": self.nodes, "vectors": self.vectors}, f)

    def load(self, path: str):
        import pickle
        if os.path.exists(path):
            with open(path, "rb") as f:
                data = pickle.load(f)
                self.nodes = data.get("nodes", [])
                self.vectors = data.get("vectors", {})

class DBClient:
    def __init__(self):
        self.is_mock = os.getenv("USE_MOCK_DB", "False") == "True"
        if self.is_mock:
            self.client = FalkorDBMock()
            print("Using FalkorDBMock as requested.")
        else:
            host = os.getenv("DB_HOST", "localhost")
            port = int(os.getenv("DB_PORT", 6379))
            # Retry loop for initial connection (helps in Docker startup races)
            retries = 5
            while retries > 0:
                try:
                    from falkordb import FalkorDB
                    self.client = FalkorDB(host=host, port=port)
                    # Verify connection and module availability
                    try:
                        self.client.select_graph("world").query("RETURN 1")
                    except Exception as e:
                        if "unknown command 'GRAPH.QUERY'" in str(e):
                            raise RuntimeError("FalkorDB module (falkordb.so) is NOT loaded in the Redis server.") from e
                        raise

                    print(f"Connected to FalkorDB at {host}:{port}")
                    return
                except Exception as e:
                    print(f"Failed to connect to FalkorDB (Retries left: {retries}): {e}")
                    retries -= 1
                    if retries > 0:
                        import time
                        time.sleep(2)

            print(f"CRITICAL: Failed to connect to live FalkorDB after all retries.")
            # We do NOT fall back to mock here anymore as per requirements
            raise RuntimeError("Could not connect to live FalkorDB.")

    def query(self, cypher: str, params: Dict = None):
        if self.is_mock:
            return self.client.query(cypher, params)
        res = self.client.select_graph("world").query(cypher, params)
        # return the result set as a list for easier len() checks and compatibility
        return res.result_set

    def player_exists(self) -> bool:
        """Robustly checks if a player exists in the database."""
        try:
            res = self.query("MATCH (p:Player) RETURN p.name LIMIT 1")
            if not res: return False
            # FalkorDB result_set is a list of lists, mock is similar
            return len(list(res)) > 0
        except:
            return False

    def save_db(self, path: str):
        if self.is_mock:
            self.client.dump(path)
        else:
            try:
                self.client.execute_command("SAVE")
            except Exception as e:
                print(f"Warning: SAVE command failed: {e}")

            rdb_source = "/data/dump.rdb"
            if os.path.exists(rdb_source):
                os.makedirs(os.path.dirname(path), exist_ok=True)
                shutil.copy(rdb_source, path)
            elif os.path.exists("dump.rdb"):
                os.makedirs(os.path.dirname(path), exist_ok=True)
                shutil.copy("dump.rdb", path)
            else:
                print("Error: Could not find dump.rdb to save.")

    def load_db(self, path: str):
        if self.is_mock:
            self.client.load(path)
        else:
            rdb_target = "/data/dump.rdb"
            # Ensure target directory exists
            os.makedirs(os.path.dirname(rdb_target), exist_ok=True)
            if os.path.exists(path):
                shutil.copy(path, rdb_target)
                print(f"Database loaded from {path} to {rdb_target}.")

db_client = DBClient()