import sqlparse
from sqlparse.sql import Comparison, Parenthesis, Token
from sqlparse.tokens import Literal
from langchain_community.utilities import SQLDatabase

from dotenv import load_dotenv
import os
load_dotenv()
# URI = os.getenv("SUPABASE_URI")
# db = SQLDatabase.from_uri(URI, sample_rows_in_table_info=5)

def get_query_columns(sql, get_real_name=False):
    stmt = sqlparse.parse(sql)[0]
    columns = []
    column_identifiers = []

    # get column_identifieres
    in_select = False
    for token in stmt.tokens:
        if isinstance(token, sqlparse.sql.Comment):
            continue
        if str(token).lower() == 'select':
            in_select = True
        elif in_select and token.ttype is None:
            if isinstance(token, sqlparse.sql.IdentifierList):
                for identifier in token.get_identifiers():
                    column_identifiers.append(identifier)
            else:
                column_identifiers.append(token)

            break

    # get column names
    for column_identifier in column_identifiers:
        if get_real_name:
            columns.append(column_identifier.get_real_name())
        else:
            columns.append(column_identifier.get_name())

    return columns


def extract_comparison_value(tokens, target):
    """Helper function to extract value based on a comparison target."""
    is_target = False
    for token in tokens:
        if token.value.strip("'\"") == target:
            is_target = True
        elif is_target and token.ttype is Literal.String.Single:
            return token.value.strip("'\"")
        elif is_target and isinstance(token, Parenthesis):
            data = db.run(token.value.strip("()"))
            return eval(data)[0][0]
    return None

def parse_sql_where(sql):
    """Parse the SQL statement to extract 排放源, 類別"""
    stmt = sqlparse.parse(sql)[0]
    column_dict = {
        "排放源": None,
        "類別": None,
        "範疇": None,
        "類別項目": None,
        "項目": None,
        
    }

    def get_column_details(token, column_args):
        if isinstance(token, Comparison):
            # print(token, type(token))
            for column_name in column_args.keys():
                if column_args[column_name] is None:
                    column_args[column_name] = extract_comparison_value(token.tokens, column_name)
                
        return column_args

    for token in stmt.tokens:
        if isinstance(token, sqlparse.sql.Comment):
            continue
        if token.value.lower().startswith('where'):
            for token2 in token.tokens:
                # print(token2, type(token2))
                if isinstance(token2, Comparison):
                    column_dict = get_column_details(token2, column_dict)
                elif isinstance(token2, Parenthesis):
                    # print(token2, type(token2))
                    for token3 in token2.tokens:
                        column_dict = get_column_details(token3, column_dict)
    column_values = [column_dict[column_name].replace("%", "") for column_name in column_dict.keys() if column_dict[column_name] is not None]
    
    return column_values

def get_table_name(sql):
    stmt = sqlparse.parse(sql)[0]

    in_from = False
    for token in stmt.tokens:
        if isinstance(token, sqlparse.sql.Comment):
            continue
        if str(token).lower() == 'from':
            in_from = True
        elif in_from and token.ttype is None:
            if isinstance(token, sqlparse.sql.Identifier):
                # print(token, token.ttype)
                return token.value

if __name__ == "__main__":
    sql_query = """
        SELECT SUM("排放量(公噸CO2e)") AS "固定燃燒總排放量"
        FROM "104_112碳排放公開及建準資料"
        WHERE "事業名稱" like '%建準%'
        AND "排放源" = '固定燃燒'
        AND "盤查標準" = 'GHG'
        AND "年度" = EXTRACT(YEAR FROM CURRENT_DATE)-1;
        """
    sql_query = """
        SELECT SUM("用電度數(kwh)") AS "綠電使用量"
        FROM "用電度數"
        WHERE "項目" = '自產電力(綠電)'
        AND "盤查標準" = 'GHG'
        AND "年度" = EXTRACT(YEAR FROM CURRENT_DATE)-1
    """
    print(get_query_columns(sql_query, get_real_name=True))
    print(parse_sql_where(sql_query))
    print(get_table_name(sql_query))