use minisql::type_system::{IndexableValue, Value};
use nom::{
    branch::alt,
    character::complete::{u64, char, digit1, none_of},
    combinator::opt,
    multi::many0,
    sequence::{delimited, pair, preceded},
    IResult, error::make_error
};

pub fn parse_db_value(input: &str) -> IResult<&str, Value> {
    alt((
        parse_string,
        parse_number,
        parse_int,
        parse_uuid,
    ))(input)
}

pub fn parse_number(input: &str) -> IResult<&str, Value> {
    // Parse the integer part
    let (input, (sign, digits)) = pair(opt(char('-')), digit1)(input)?;

    // Parse the fractional part
    let (input, frac_part) = opt(pair(char('.'), digit1))(input)?;

    match frac_part {
        Some((_fsign, fdigits)) => {
            // Combine integer and fractional parts
            let combined_parts = format!(
                "{}{}.{}",
                sign.unwrap_or('+'),
                digits,
                fdigits
            );
            // Parse the combined parts as a floating-point number
            let value = combined_parts.parse::<f64>()
                .map_err(|_| {
                    nom::Err::Failure(make_error(input, nom::error::ErrorKind::Fail))
                })?;
            Ok((input, Value::Number(value)))
        }
        None => {
            let value = format!("{}{}", sign.unwrap_or('+'), digits).parse::<u64>()
                .map_err(|_| {
                    nom::Err::Failure(make_error(input, nom::error::ErrorKind::Fail))
                })?;
            Ok((input, Value::Indexable(IndexableValue::Int(value))))
        }
    }
}

pub fn parse_int(input: &str) -> IResult<&str, Value> {
    u64(input).map(|(input, v)| {
        (input, Value::Indexable(IndexableValue::Int(v)))
    })
}

fn escape_tab(input:&str) -> IResult<&str, char> {
    let (input, _) = preceded(char('\\'), char('t'))(input)?;
    Ok((input, '\t'))
}

fn escape_backslash(input:&str) -> IResult<&str, char> {
    let (input, _) = preceded(char('\\'), char('\\'))(input)?;
    Ok((input, '\\'))
}

fn escape_newline(input:&str) -> IResult<&str, char> {
    let (input, _) = preceded(char('\\'), char('n'))(input)?;
    Ok((input, '\n'))
}

fn escape_carriegereturn(input:&str) -> IResult<&str, char> {
    let (input, _) = preceded(char('\\'), char('r'))(input)?;
    Ok((input, '\r'))
}

fn escape_doublequote(input:&str) -> IResult<&str, char> {
    preceded(char('\\'), char('"'))(input)
}

pub fn parse_string(input: &str) -> IResult<&str, Value> {
    // Parse the content inside the double quotes
    let (input, content) = delimited(
        char('"'),
        many0(alt((
            escape_backslash,
            escape_carriegereturn,
            escape_newline,
            escape_doublequote,
            escape_tab,
            none_of(r#"\""#)
        ))),
        char('"'),
    )(input)?;

    // Combine the characters into a string
    let value: String = content.into_iter().collect();

    Ok((input, Value::Indexable(IndexableValue::String(value))))
}

pub fn parse_uuid(input: &str) -> IResult<&str, Value> {
    let (input, value) = pair(char('u'), u64)(input).map(|(input, (_, v))| {
        (input, Value::Indexable(IndexableValue::Uuid(v)))
    })?;
    Ok((input, value))
}

#[cfg(test)]
mod tests {
    use minisql::type_system::{IndexableValue, Value};
    use crate::parsing::literal::{parse_db_value, parse_string, parse_uuid};


    #[test]
    fn test_string_parser() {
        assert_eq!(parse_string(r#""simple""#), Ok(("", Value::Indexable(IndexableValue::String(String::from("simple"))))));
        assert_eq!(parse_string(r#""\"\t\r\n\\""#), Ok(("", Value::Indexable(IndexableValue::String(String::from("\"\t\r\n\\"))))));
        assert_eq!(parse_string(r#""name is \"John\".""#), Ok(("", Value::Indexable(IndexableValue::String(String::from("name is \"John\"."))))));
    }

    #[test]
    fn test_parse_db_value() {
        let (input, value) = parse_db_value("5").expect("should parse");
        assert_eq!(input, "");
        assert_eq!(value, Value::Indexable(IndexableValue::Int(5)));

        let (input, value) = parse_db_value("5.5").expect("should parse");
        assert_eq!(input, "");
        assert_eq!(value, Value::Number(5.5));

        let (_, _) = parse_db_value("\"STRING\"").expect("should parse");
        let (input, value) = parse_db_value("\"abcdefghkjklmnopqrstuvwxyz!@#$%^&*()_+ \"").expect("should parse");
        assert_eq!(input, "");
        assert_eq!(value, Value::Indexable(IndexableValue::String("abcdefghkjklmnopqrstuvwxyz!@#$%^&*()_+ ".to_string())));
        
    }


    #[test]
    fn test_parse_positive_float() {
        assert_eq!(parse_db_value("23.213313"), Ok(("", Value::Number(23.213313))));
        assert_eq!(parse_db_value("2241.9734"), Ok(("", Value::Number(2241.9734))));
    }

    #[test]
    fn test_parse_negative_float() {
        assert_eq!(parse_db_value("-9241.873654"), Ok(("", Value::Number(-9241.873654))));
        assert_eq!(parse_db_value("-62625.0"), Ok(("", Value::Number(-62625.0))));
    }

    #[test]
    fn test_parse_float_between_0_and_1() {
        assert_eq!(parse_db_value("0.873654"), Ok(("", Value::Number(0.873654))));
        assert_eq!(parse_db_value("0.62625"), Ok(("", Value::Number(0.62625))));
    }


    #[test]
    fn test_parse_int() {
        assert_eq!(parse_db_value("5134616"), Ok(("", Value::Indexable(IndexableValue::Int(5134616)))));
    }

    #[test]
    fn test_parse_uuid() {
        assert_eq!(parse_uuid("u131515"), Ok(("", Value::Indexable(IndexableValue::Uuid(131515)))))
    }
}