import os
import requests
import time
import re
import json
from db_utils import get_schema, execute_sql

def query_gemini_api(prompt, max_retries=3):
    """Query the Google Gemini API"""
    api_key = os.getenv("GOOGLE_API_KEY")
    if not api_key:
        raise ValueError("GOOGLE_API_KEY not found in environment variables")
    
    url = f"https://generativelanguage.googleapis.com/v1beta/models/gemini-1.5-flash:generateContent?key={api_key}"
    
    headers = {
        "Content-Type": "application/json"
    }
    
    payload = {
        "contents": [{
            "parts": [{
                "text": prompt
            }]
        }],
        "generationConfig": {
            "temperature": 0.1,
            "topK": 1,
            "topP": 0.8,
            "maxOutputTokens": 200,
            "stopSequences": ["```", "\n\n"]
        },
        "safetySettings": [
            {
                "category": "HARM_CATEGORY_HARASSMENT",
                "threshold": "BLOCK_NONE"
            },
            {
                "category": "HARM_CATEGORY_HATE_SPEECH",
                "threshold": "BLOCK_NONE"
            },
            {
                "category": "HARM_CATEGORY_SEXUALLY_EXPLICIT",
                "threshold": "BLOCK_NONE"
            },
            {
                "category": "HARM_CATEGORY_DANGEROUS_CONTENT",
                "threshold": "BLOCK_NONE"
            }
        ]
    }
    
    for attempt in range(max_retries):
        try:
            response = requests.post(url, headers=headers, json=payload, timeout=30)
            
            if response.status_code == 200:
                result = response.json()
                if "candidates" in result and len(result["candidates"]) > 0:
                    candidate = result["candidates"][0]
                    if candidate.get('finishReason') == 'SAFETY':
                        return "Error: The response was blocked by safety filters."
                    if "content" in candidate and "parts" in candidate["content"]:
                        generated_text = candidate["content"]["parts"][0]["text"].strip()
                        return generated_text
                
                return "No valid response generated"
            
            elif response.status_code == 429:
                wait_time = 60 * (attempt + 1)
                time.sleep(wait_time)
                continue
            else:
                error_msg = f"Gemini API Error {response.status_code}: {response.text}"
                if attempt == max_retries - 1:
                    raise Exception(error_msg)
                    
        except requests.exceptions.Timeout:
            if attempt == max_retries - 1:
                raise Exception("Request timed out after multiple attempts")
            time.sleep(5)
            
        except Exception as e:
            if attempt == max_retries - 1:
                raise e
            time.sleep(5)
    
    raise Exception("Failed to get response after all retries")

def extract_user_requested_limit(nl_query):
    """Extract user-requested number from natural language query"""
    patterns = [
        r'\b(\d+)\s+(?:ships?|vessels?|boats?|records?|results?|entries?|names?)\b',
        r'(?:show|list|find|get)\s+(?:me\s+)?(?:the\s+)?(?:top\s+|first\s+)?(\d+)',
        r'(?:names\s+of\s+)(\d+)\s+',
        r'\b(\d+)\s+(?:oldest|newest|biggest|smallest|largest)',
    ]
    
    for pattern in patterns:
        match = re.search(pattern, nl_query, re.IGNORECASE)
        if match:
            return int(match.group(1))
    return None

def clean_sql_output(sql_text, user_limit=None):
    """Clean and validate SQL output from the model"""
    sql_text = sql_text.strip()
    
    if sql_text.startswith("```"):
        lines = sql_text.split('\n')
        sql_lines = []
        in_sql = False
        for line in lines:
            if line.strip().startswith("```"):
                in_sql = not in_sql
                continue
            if in_sql:
                sql_lines.append(line)
        sql_text = '\n'.join(sql_lines)
    
    lines = sql_text.split('\n')
    sql = ""
    for line in lines:
        line = line.strip()
        if line and (line.upper().startswith('SELECT') or sql):
            sql += line + " "
            if line.endswith(';'):
                break
    
    if not sql:
        for line in lines:
            line = line.strip()
            if line and any(keyword in line.upper() for keyword in ['SELECT', 'WITH', 'FROM']):
                sql = line
                break
    
    sql = sql.strip().rstrip(';')
    
    if user_limit:
        sql = re.sub(r'\s+LIMIT\s+\d+', '', sql, flags=re.IGNORECASE)
        sql += f" LIMIT {user_limit}"
    
    return sql

def text_to_sql(nl_query):
    """Convert natural language to SQL using Google Gemini"""
    try:
        schema = get_schema()
        user_limit = extract_user_requested_limit(nl_query)
        
        prompt = f"""You are an expert PostgreSQL developer. Convert this natural language question to a precise SQL query.

Question: {nl_query}

Database Schema:
{schema[:1500]}

Requirements:
- Generate ONLY the SQL query, no explanation
- Use PostgreSQL syntax
- Be precise with table and column names from the schema
- Return a single SELECT statement

SQL Query:"""

        generated_sql = query_gemini_api(prompt)
        
        if not generated_sql or "No valid response" in generated_sql or "Error:" in generated_sql:
            return generated_sql, []
        
        sql = clean_sql_output(generated_sql, user_limit)
        
        if not sql or not sql.upper().strip().startswith('SELECT'):
            return f"Error: Invalid SQL generated: {sql}", []
        
        results = execute_sql(sql)
        return sql, results
        
    except Exception as e:
        return f"Error: {str(e)}", []

#--end-of-script