"""
LinkSyncServer - Query Engine
"""

from fastapi import APIRouter, HTTPException
from typing import List, Optional, Dict, Any
import re
import uuid

router = APIRouter(prefix="/api/queries", tags=["Queries"])


def tokenize(query: str) -> List[str]:
    """Tokenize query string."""
    # Remove parentheses first, tokenize, then track nesting
    tokens = []
    current_token = ""
    paren_depth = 0
    i = 0
    while i < len(query):
        c = query[i]
        if c == '(':
            paren_depth += 1
            current_token += c
        elif c == ')':
            paren_depth -= 1
            current_token += c
        elif c in ' \t\n' or paren_depth == 0 and c in ' ,':
            if current_token:
                tokens.append(current_token)
                current_token = ""
        else:
            current_token += c
        i += 1
    if current_token:
        tokens.append(current_token)
    return tokens


class TermSet:
    """Term set: ('term1', 'term2') -> OR operation"""
    def __init__(self, terms: List[str]):
        self.terms = terms
        self.operation = "OR"
    
    def to_dict(self) -> Dict[str, Any]:
        return {
            "type": "term_set",
            "terms": self.terms,
            "operation": self.operation
        }


class TagFilter:
    """Tag-based filter"""
    def __init__(self, tag_name: str):
        self.tag_name = tag_name
        self.operation = "TAG"
    
    def to_dict(self) -> Dict[str, Any]:
        return {
            "type": "tag_filter",
            "tag_name": self.tag_name,
            "operation": self.operation
        }


class FieldFilter:
    """Field-based filter (e.g., url:example.com)"""
    def __init__(self, field: str, value: str):
        self.field = field
        self.value = value
        self.operation = "FIELD"
    
    def to_dict(self) -> Dict[str, Any]:
        return {
            "type": "field_filter",
            "field": self.field,
            "value": self.value,
            "operation": self.operation
        }


class ANDNode:
    """AND operation node"""
    def __init__(self, left, right):
        self.left = left
        self.right = right
        self.operation = "AND"
    
    def to_dict(self) -> Dict[str, Any]:
        return {
            "type": "binary",
            "operation": self.operation,
            "left": self.left.to_dict(),
            "right": self.right.to_dict()
        }


class ORNode:
    """OR operation node"""
    def __init__(self, left, right):
        self.left = left
        self.right = right
        self.operation = "OR"
    
    def to_dict(self) -> Dict[str, Any]:
        return {
            "type": "binary",
            "operation": self.operation,
            "left": self.left.to_dict(),
            "right": self.right.to_dict()
        }


class XORNode:
    """XOR operation node"""
    def __init__(self, left, right):
        self.left = left
        self.right = right
        self.operation = "XOR"
    
    def to_dict(self) -> Dict[str, Any]:
        return {
            "type": "binary",
            "operation": self.operation,
            "left": self.left.to_dict(),
            "right": self.right.to_dict()
        }


class NOTNode:
    """NOT operation node"""
    def __init__(self, child):
        self.child = child
        self.operation = "NOT"
    
    def to_dict(self) -> Dict[str, Any]:
        return {
            "type": "unary",
            "operation": self.operation,
            "child": self.child.to_dict()
        }


def parse_query(query: str) -> Dict[str, Any]:
    """
    Parse query expression: ('term1', 'term2') OR tagA AND tagB XOR url:example.com
    Precedence: () > XOR > AND > OR
    """
    tokens = tokenize(query)
    
    # Remove parentheses and tokenize
    tokens = tokenize(query)
    
    # Simple parser for basic queries
    # For full parser, would need recursive descent
    
    # Handle term sets: ('term1', 'term2')
    term_set = None
    i = 0
    while i < len(tokens):
        token = tokens[i]
        if token.startswith('(') and tokens[i].endswith(')'):
            # Extract terms from tuple
            inner = token[1:-1]
            terms = [t.strip("'\"") for t in inner.split(',')]
            term_set = TermSet(terms)
            i += 1
        else:
            break
    
    if not term_set:
        # Parse as simple expression
        # This is a simplified parser for demo
        return {"type": "term_set", "terms": []}
    
    return term_set.to_dict()


def execute_query(query_expression: dict, all_bookmarks: List[dict]) -> List[dict]:
    """
    Execute query expression against bookmark list.
    For demo, returns mock results.
    """
    # Query AST evaluation would go here
    # For now, return mock results
    return [
        {
            "id": str(uuid.uuid4()),
            "url": "https://example.com/result",
            "title": "Query Result",
            "description": "A result from the query",
            "notes": "",
            "tags": ["query", "result"],
            "favicon_url": None,
            "path": "/Query Result",
            "created_at": "2026-05-11T00:00:00Z",
            "updated_at": "2026-05-11T00:00:00Z",
            "visit_count": 0,
            "is_bookmarked": False,
            "source_set_id": None
        }
    ]


@router.post("/parse", response_model=Dict[str, Any])
async def parse_expression(query: str):
    """Parse and validate query expression."""
    parsed = parse_query(query)
    return {
        "expression": query,
        "parsed": parsed,
        "valid": True
    }


@router.post("/execute", response_model=List[dict])
async def execute(query_expression: dict, limit: int = 20):
    """Execute query against bookmarks."""
    # For demo, return mock results
    return [
        {
            "id": str(uuid.uuid4()),
            "url": "https://example.com/queried",
            "title": "Queried Item",
            "description": "Item from query",
            "notes": "",
            "tags": ["queried"],
            "favicon_url": None,
            "path": "/Queried",
            "created_at": "2026-05-11T00:00:00Z",
            "updated_at": "2026-05-11T00:00:00Z",
            "visit_count": 0,
            "is_bookmarked": False,
            "source_set_id": None
        }
    ]


@router.get("/{query_id}", response_model=Dict[str, Any])
async def get_saved_query(query_id: str):
    """Get saved query by ID."""
    return {
        "id": query_id,
        "name": "Example Query",
        "description": "Example query description",
        "expression": "('work', 'dev') OR tag:work",
        "query_type": "dynamic",
        "is_public": False,
        "created_at": "2026-05-11T00:00:00Z",
        "updated_at": "2026-05-11T00:00:00Z"
    }