use nom::{
    branch::alt,
    bytes::complete::{escaped_transform, tag},
    character::complete::{alpha1, digit1, multispace0, multispace1, none_of},
    combinator::{opt, value},
    multi::{many0, many1, separated_list1},
    sequence::delimited,
    IResult,
};
use std::num::ParseIntError;

#[derive(Debug)]
pub enum ParseSizeError {
    ParseIntError(ParseIntError),
    InsufficientArguments,
}

impl From<ParseIntError> for ParseSizeError {
    fn from(e: ParseIntError) -> Self {
        Self::ParseIntError(e)
    }
}

#[derive(Clone, Debug, PartialEq)]
pub struct Size {
    pub width: i32,
    pub height: i32,
}

impl TryFrom<&str> for Size {
    type Error = ParseSizeError;
    fn try_from(s: &str) -> Result<Self, Self::Error> {
        let parts = s
            .split(':')
            .map(|v| v.parse::<i32>())
            .collect::<Result<Vec<i32>, ParseIntError>>()?;
        match parts[..] {
            [width, height, ..] => Ok(Size { width, height }),
            [dim] => Ok(Size {
                width: dim,
                height: dim,
            }),
            [] => Err(ParseSizeError::InsufficientArguments),
        }
    }
}

#[derive(Debug, PartialEq)]
pub struct Tree {
    pub sequence: Vec<Node>,
    pub sub_sequences: Vec<Tree>,
}

impl ToString for Tree {
    fn to_string(&self) -> String {
        let sequence = self
            .sequence
            .iter()
            .map(|node| node.to_string())
            .collect::<String>();
        let subsequences = self
            .sub_sequences
            .iter()
            .map(|seq| seq.to_string())
            .collect::<String>();
        format!("({}{})", sequence, subsequences)
    }
}

#[derive(Debug, PartialEq)]
pub struct Node {
    pub properties: Vec<Property>,
}

impl ToString for Node {
    fn to_string(&self) -> String {
        let props = self
            .properties
            .iter()
            .map(|prop| prop.to_string())
            .collect::<String>();
        format!(";{}", props)
    }
}

impl Node {
    pub fn find_prop(&self, ident: &str) -> Option<Property> {
        self.properties
            .iter()
            .find(|prop| prop.ident == ident)
            .cloned()
    }
}

#[derive(Clone, Debug, PartialEq)]
pub struct Property {
    pub ident: String,
    pub values: Vec<String>,
}

impl ToString for Property {
    fn to_string(&self) -> String {
        let values = self
            .values
            .iter()
            .map(|val| format!("[{}]", val))
            .collect::<String>();
        format!("{}{}", self.ident, values)
    }
}

pub fn parse_collection<'a, E: nom::error::ParseError<&'a str>>(
    input: &'a str,
) -> IResult<&'a str, Vec<Tree>, E> {
    separated_list1(multispace1, parse_tree)(input)
}

// note: must preserve unknown properties
// note: must fix or preserve illegally formatted game-info properties
// note: must correct or delete illegally foramtted properties, but display a warning
fn parse_tree<'a, E: nom::error::ParseError<&'a str>>(input: &'a str) -> IResult<&'a str, Tree, E> {
    let (input, _) = multispace0(input)?;
    delimited(tag("("), parse_sequence, tag(")"))(input)
}

fn parse_sequence<'a, E: nom::error::ParseError<&'a str>>(
    input: &'a str,
) -> IResult<&'a str, Tree, E> {
    let (input, _) = multispace0(input)?;
    let (input, nodes) = many1(parse_node)(input)?;
    let (input, _) = multispace0(input)?;
    let (input, sub_sequences) = many0(parse_tree)(input)?;
    let (input, _) = multispace0(input)?;

    Ok((
        input,
        Tree {
            sequence: nodes,
            sub_sequences,
        },
    ))
}

fn parse_node<'a, E: nom::error::ParseError<&'a str>>(input: &'a str) -> IResult<&'a str, Node, E> {
    let (input, _) = multispace0(input)?;
    let (input, _) = tag(";")(input)?;
    let (input, properties) = many1(parse_property)(input)?;
    Ok((input, Node { properties }))
}

fn parse_property<'a, E: nom::error::ParseError<&'a str>>(
    input: &'a str,
) -> IResult<&'a str, Property, E> {
    let (input, _) = multispace0(input)?;
    let (input, ident) = alpha1(input)?;
    let (input, values) = many1(parse_propval)(input)?;
    let (input, _) = multispace0(input)?;

    let values = values
        .into_iter()
        .map(|v| v.to_owned())
        .collect::<Vec<String>>();
    Ok((
        input,
        Property {
            ident: ident.to_owned(),
            values,
        },
    ))
}

fn parse_propval<'a, E: nom::error::ParseError<&'a str>>(
    input: &'a str,
) -> IResult<&'a str, String, E> {
    let (input, _) = multispace0(input)?;
    let (input, _) = tag("[")(input)?;
    let (input, value) = parse_propval_text(input)?;
    let (input, _) = tag("]")(input)?;

    Ok((input, value.unwrap_or(String::new())))
}

fn parse_propval_text<'a, E: nom::error::ParseError<&'a str>>(
    input: &'a str,
) -> IResult<&'a str, Option<String>, E> {
    let (input, value) = opt(escaped_transform(
        none_of("\\]"),
        '\\',
        alt((
            value("]", tag("]")),
            value("\\", tag("\\")),
            value("", tag("\n")),
        )),
    ))(input)?;
    Ok((input, value.map(|v| v.to_owned())))
}

pub fn parse_size<'a, E: nom::error::ParseError<&'a str>>(
    input: &'a str,
) -> IResult<&'a str, Size, E> {
    let (input, dimensions) = separated_list1(tag(":"), digit1)(input)?;
    let (width, height) = match dimensions.as_slice() {
        [width] => (width.parse::<i32>().unwrap(), width.parse::<i32>().unwrap()),
        [width, height] => (
            width.parse::<i32>().unwrap(),
            height.parse::<i32>().unwrap(),
        ),
        _ => (19, 19),
    };
    Ok((input, Size { width, height }))
}

#[cfg(test)]
mod test {
    use std::{fs::File, io::Read};

    use super::*;

    const EXAMPLE: &'static str = "(;FF[4]C[root](;C[a];C[b](;C[c])
(;C[d];C[e]))
(;C[f](;C[g];C[h];C[i])
(;C[j])))";

    #[test]
    fn it_can_parse_properties() {
        let (_, prop) = parse_property::<nom::error::VerboseError<&str>>("C[a]").unwrap();
        assert_eq!(
            prop,
            Property {
                ident: "C".to_owned(),
                values: vec!["a".to_owned()]
            }
        );

        let (_, prop) = parse_property::<nom::error::VerboseError<&str>>("C[a][b][c]").unwrap();
        assert_eq!(
            prop,
            Property {
                ident: "C".to_owned(),
                values: vec!["a".to_owned(), "b".to_owned(), "c".to_owned()]
            }
        );
    }

    #[test]
    fn it_can_parse_a_standalone_node() {
        let (_, node) = parse_node::<nom::error::VerboseError<&str>>(";B[ab]").unwrap();

        assert_eq!(
            node,
            Node {
                properties: vec![Property {
                    ident: "B".to_owned(),
                    values: vec!["ab".to_owned()]
                }]
            }
        );

        let (_, node) =
            parse_node::<nom::error::VerboseError<&str>>(";B[ab];W[dp];B[pq]C[some comments]")
                .unwrap();

        assert_eq!(
            node,
            Node {
                properties: vec![Property {
                    ident: "B".to_owned(),
                    values: vec!["ab".to_owned()]
                }]
            }
        );
    }

    #[test]
    fn it_can_parse_a_simple_sequence() {
        let (_, sequence) =
            parse_tree::<nom::error::VerboseError<&str>>("(;B[ab];W[dp];B[pq]C[some comments])")
                .unwrap();

        assert_eq!(
            sequence,
            Tree {
                sequence: vec![
                    Node {
                        properties: vec![Property {
                            ident: "B".to_owned(),
                            values: vec!["ab".to_owned()]
                        }]
                    },
                    Node {
                        properties: vec![Property {
                            ident: "W".to_owned(),
                            values: vec!["dp".to_owned()]
                        }]
                    },
                    Node {
                        properties: vec![
                            Property {
                                ident: "B".to_owned(),
                                values: vec!["pq".to_owned()]
                            },
                            Property {
                                ident: "C".to_owned(),
                                values: vec!["some comments".to_owned()]
                            }
                        ]
                    }
                ],
                sub_sequences: vec![],
            }
        );
    }

    #[test]
    fn it_can_parse_a_sequence_with_subsequences() {
        let text = "(;C[a];C[b](;C[c])(;C[d];C[e]))";
        let (_, sequence) = parse_tree::<nom::error::VerboseError<&str>>(text).unwrap();

        let main_sequence = vec![
            Node {
                properties: vec![Property {
                    ident: "C".to_owned(),
                    values: vec!["a".to_owned()],
                }],
            },
            Node {
                properties: vec![Property {
                    ident: "C".to_owned(),
                    values: vec!["b".to_owned()],
                }],
            },
        ];
        let subsequence_1 = Tree {
            sequence: vec![Node {
                properties: vec![Property {
                    ident: "C".to_owned(),
                    values: vec!["c".to_owned()],
                }],
            }],
            sub_sequences: vec![],
        };
        let subsequence_2 = Tree {
            sequence: vec![
                Node {
                    properties: vec![Property {
                        ident: "C".to_owned(),
                        values: vec!["d".to_owned()],
                    }],
                },
                Node {
                    properties: vec![Property {
                        ident: "C".to_owned(),
                        values: vec!["e".to_owned()],
                    }],
                },
            ],
            sub_sequences: vec![],
        };

        assert_eq!(
            sequence,
            Tree {
                sequence: main_sequence,
                sub_sequences: vec![subsequence_1, subsequence_2],
            }
        );
    }

    #[test]
    fn it_can_parse_example_1() {
        let (_, ex_tree) = parse_tree::<nom::error::VerboseError<&str>>(EXAMPLE).unwrap();
        assert_eq!(ex_tree.sequence.len(), 1);

        assert_eq!(ex_tree.sequence[0].properties.len(), 2);
        assert_eq!(
            ex_tree.sequence[0].properties[0],
            Property {
                ident: "FF".to_owned(),
                values: vec!["4".to_owned()]
            }
        );
        assert_eq!(ex_tree.sub_sequences.len(), 2);

        assert_eq!(ex_tree.sub_sequences[0].sequence.len(), 2);
        assert_eq!(
            ex_tree.sub_sequences[0].sequence,
            vec![
                Node {
                    properties: vec![Property {
                        ident: "C".to_owned(),
                        values: vec!["a".to_owned()]
                    }]
                },
                Node {
                    properties: vec![Property {
                        ident: "C".to_owned(),
                        values: vec!["b".to_owned()]
                    }]
                },
            ]
        );
        assert_eq!(ex_tree.sub_sequences[0].sub_sequences.len(), 2);
    }

    #[test]
    fn it_can_regenerate_the_tree() {
        let (_, tree1) = parse_tree::<nom::error::VerboseError<&str>>(EXAMPLE).unwrap();
        assert_eq!(
            tree1.to_string(),
            "(;FF[4]C[root](;C[a];C[b](;C[c])(;C[d];C[e]))(;C[f](;C[g];C[h];C[i])(;C[j])))"
        );
        let (_, tree2) = parse_tree::<nom::error::VerboseError<&str>>(&tree1.to_string()).unwrap();
        assert_eq!(tree1, tree2);
    }

    #[test]
    fn it_parses_propvals() {
        let (_, propval) = parse_propval::<nom::error::VerboseError<&str>>("[]").unwrap();
        assert_eq!(propval, "".to_owned());

        let (_, propval) =
            parse_propval::<nom::error::VerboseError<&str>>("[normal propval]").unwrap();
        assert_eq!(propval, "normal propval".to_owned());

        let (_, propval) =
            parse_propval::<nom::error::VerboseError<&str>>(r"[need an [escape\] in the propval]")
                .unwrap();
        assert_eq!(propval, "need an [escape] in the propval".to_owned());
    }

    #[test]
    fn it_parses_propvals_with_hard_linebreaks() {
        let (_, propval) = parse_propval_text::<nom::error::VerboseError<&str>>(
            "There are hard linebreaks & soft linebreaks.
Soft linebreaks...",
        )
        .unwrap();
        assert_eq!(
            propval,
            Some(
                "There are hard linebreaks & soft linebreaks.
Soft linebreaks..."
                    .to_owned()
            )
        );
    }

    #[test]
    fn it_parses_propvals_with_escaped_closing_brackets() {
        let (_, propval) =
            parse_propval_text::<nom::error::VerboseError<&str>>(r"escaped closing \] bracket")
                .unwrap();
        assert_eq!(
            propval,
            Some(r"escaped closing ] bracket".to_owned()).to_owned()
        );
    }

    #[test]
    fn it_parses_propvals_with_soft_linebreaks() {
        let (_, propval) = parse_propval_text::<nom::error::VerboseError<&str>>(
            r"Soft linebreaks are linebreaks preceeded by '\\' like this one >o\
k<. Hard line breaks are all other linebreaks.",
        )
        .unwrap();
        assert_eq!(
            propval,
            Some("Soft linebreaks are linebreaks preceeded by '\\' like this one >ok<. Hard line breaks are all other linebreaks.".to_owned())
                .to_owned()
        );
    }

    #[test]
    fn it_parses_sgf_with_newline_in_sequence() {
        let data = String::from(
            "(;FF[4]C[root](;C[a];C[b](;C[c])(;C[d];C[e]
))(;C[f](;C[g];C[h];C[i])(;C[j])))",
        );
        parse_tree::<nom::error::VerboseError<&str>>(&data).unwrap();
    }

    #[test]
    fn it_parses_sgf_with_newline_between_two_sequence_closings() {
        let data = String::from(
            "(;FF[4]C[root](;C[a];C[b](;C[c])(;C[d];C[e])
)(;C[f](;C[g];C[h];C[i])(;C[j])))",
        );
        parse_tree::<nom::error::VerboseError<&str>>(&data).unwrap();
    }
}