#![cfg_attr(feature = "nightly", feature(step_trait, step_trait_ext))]

use std::marker::PhantomData;
use std::path::PathBuf;

#[cfg(feature = "nightly")]
use std::iter::Step;

use serde::{Deserialize, Serialize};

pub mod compiler;

#[derive(Debug, Hash, PartialEq, Eq, PartialOrd, Ord)]
pub struct Column<I: Indexed>(pub u32, PhantomData<I>);

impl<I: Indexed> Column<I> {
    fn new(c: u32) -> Column<I> {
        Column(c, PhantomData)
    }
}

impl<I: Indexed> Clone for Column<I> {
    fn clone(&self) -> Column<I> {
        *self
    }
}

impl<I: Indexed> Copy for Column<I> {}

impl<I: Indexed> Serialize for Column<I> {
    fn serialize<S: serde::Serializer>(
        &self,
        s: S,
    ) -> Result<<S as serde::Serializer>::Ok, <S as serde::Serializer>::Error> {
        s.serialize_u32(self.0)
    }
}

impl<'dt, I: Indexed> Deserialize<'dt> for Column<I> {
    fn deserialize<D: serde::Deserializer<'dt>>(
        d: D,
    ) -> std::result::Result<Self, <D as serde::Deserializer<'dt>>::Error> {
        <u32 as Deserialize>::deserialize(d).map(Column::new)
    }
}

#[cfg(feature = "serialize-rustc")]
impl<I: Indexed> rustc_serialize::Decodable for Column<I> {
    fn decode<D: rustc_serialize::Decoder>(d: &mut D) -> Result<Column<I>, D::Error> {
        d.read_u32().map(Column::new)
    }
}

#[cfg(feature = "serialize-rustc")]
impl<I: Indexed> rustc_serialize::Encodable for Column<I> {
    fn encode<S: rustc_serialize::Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
        s.emit_u32(self.0)
    }
}

impl Column<OneIndexed> {
    pub fn new_one_indexed(c: u32) -> Column<OneIndexed> {
        Column(c, PhantomData)
    }

    pub fn zero_indexed(self) -> Column<ZeroIndexed> {
        Column(self.0 - 1, PhantomData)
    }
}

impl Column<ZeroIndexed> {
    pub fn new_zero_indexed(c: u32) -> Column<ZeroIndexed> {
        Column(c, PhantomData)
    }

    pub fn one_indexed(self) -> Column<OneIndexed> {
        Column(self.0 + 1, PhantomData)
    }
}

#[cfg(feature = "nightly")]
macro_rules! impl_step {
    ($target: ty) => {
        unsafe impl Step for $target {
            fn steps_between(start: &Self, end: &Self) -> Option<usize> {
                Step::steps_between(&start.0, &end.0)
            }
            fn forward_checked(arg: Self, count: usize) -> Option<Self> {
                Step::forward_checked(arg.0, count).map(|x| Self(x, PhantomData))
            }
            fn backward_checked(arg: Self, count: usize) -> Option<Self> {
                Step::backward_checked(arg.0, count).map(|x| Self(x, PhantomData))
            }
        }
    };
}

#[cfg(feature = "nightly")]
impl_step!(Column<ZeroIndexed>);
#[cfg(feature = "nightly")]
impl_step!(Column<OneIndexed>);
#[cfg(feature = "nightly")]
impl_step!(Row<ZeroIndexed>);
#[cfg(feature = "nightly")]
impl_step!(Row<OneIndexed>);

#[derive(Debug, Hash, PartialEq, Eq, PartialOrd, Ord)]
pub struct Row<I: Indexed>(pub u32, PhantomData<I>);

impl<I: Indexed> Row<I> {
    fn new(c: u32) -> Row<I> {
        Row(c, PhantomData)
    }
}

impl<I: Indexed> Clone for Row<I> {
    fn clone(&self) -> Row<I> {
        *self
    }
}

impl<I: Indexed> Copy for Row<I> {}

impl<I: Indexed> serde::Serialize for Row<I> {
    fn serialize<S: serde::Serializer>(&self, s: S) -> Result<S::Ok, S::Error> {
        s.serialize_u32(self.0)
    }
}

impl<'dt, I: Indexed> serde::Deserialize<'dt> for Row<I> {
    fn deserialize<D: serde::Deserializer<'dt>>(d: D) -> std::result::Result<Self, D::Error> {
        <u32 as Deserialize>::deserialize(d).map(Row::new)
    }
}

#[cfg(feature = "serialize-rustc")]
impl<I: Indexed> rustc_serialize::Decodable for Row<I> {
    fn decode<D: rustc_serialize::Decoder>(d: &mut D) -> Result<Row<I>, D::Error> {
        d.read_u32().map(Row::new)
    }
}

#[cfg(feature = "serialize-rustc")]
impl<I: Indexed> rustc_serialize::Encodable for Row<I> {
    fn encode<S: rustc_serialize::Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
        s.emit_u32(self.0)
    }
}

impl Row<OneIndexed> {
    pub fn new_one_indexed(c: u32) -> Row<OneIndexed> {
        Row(c, PhantomData)
    }

    pub fn zero_indexed(self) -> Row<ZeroIndexed> {
        Row(self.0 - 1, PhantomData)
    }
}

impl Row<ZeroIndexed> {
    pub fn new_zero_indexed(c: u32) -> Row<ZeroIndexed> {
        Row(c, PhantomData)
    }

    pub fn one_indexed(self) -> Row<OneIndexed> {
        Row(self.0 + 1, PhantomData)
    }
}

#[cfg_attr(feature = "derive", derive(Serialize, Deserialize))]
#[cfg_attr(feature = "serialize-rustc", derive(RustcDecodable, RustcEncodable))]
#[derive(Debug, Hash, PartialEq, Eq, PartialOrd, Ord)]
pub struct Position<I: Indexed> {
    pub row: Row<I>,
    pub col: Column<I>,
}

impl<I: Indexed> Position<I> {
    pub fn new(row: Row<I>, col: Column<I>) -> Position<I> {
        Position { row, col }
    }
}

impl<I: Indexed> Clone for Position<I> {
    fn clone(&self) -> Position<I> {
        *self
    }
}

impl<I: Indexed> Copy for Position<I> {}

impl Position<OneIndexed> {
    pub fn zero_indexed(self) -> Position<ZeroIndexed> {
        Position { row: self.row.zero_indexed(), col: self.col.zero_indexed() }
    }
}

impl Position<ZeroIndexed> {
    pub fn one_indexed(self) -> Position<OneIndexed> {
        Position { row: self.row.one_indexed(), col: self.col.one_indexed() }
    }
}

#[cfg_attr(feature = "derive", derive(Serialize, Deserialize))]
#[cfg_attr(feature = "serialize-rustc", derive(RustcDecodable, RustcEncodable))]
#[derive(Debug, Hash, PartialEq, Eq, PartialOrd, Ord)]
pub struct Range<I: Indexed> {
    pub row_start: Row<I>,
    pub row_end: Row<I>,
    pub col_start: Column<I>,
    pub col_end: Column<I>,
}

impl<I: Indexed> Range<I> {
    pub fn new(
        row_start: Row<I>,
        row_end: Row<I>,
        col_start: Column<I>,
        col_end: Column<I>,
    ) -> Range<I> {
        Range { row_start, row_end, col_start, col_end }
    }

    pub fn from_positions(start: Position<I>, end: Position<I>) -> Range<I> {
        Range { row_start: start.row, row_end: end.row, col_start: start.col, col_end: end.col }
    }

    pub fn start(self) -> Position<I> {
        Position { row: self.row_start, col: self.col_start }
    }

    pub fn end(self) -> Position<I> {
        Position { row: self.row_end, col: self.col_end }
    }
}

impl<I: Indexed> Clone for Range<I> {
    fn clone(&self) -> Range<I> {
        *self
    }
}

impl<I: Indexed> Copy for Range<I> {}

impl Range<OneIndexed> {
    pub fn zero_indexed(self) -> Range<ZeroIndexed> {
        Range {
            row_start: self.row_start.zero_indexed(),
            row_end: self.row_end.zero_indexed(),
            col_start: self.col_start.zero_indexed(),
            col_end: self.col_end.zero_indexed(),
        }
    }
}

impl Range<ZeroIndexed> {
    pub fn one_indexed(self) -> Range<OneIndexed> {
        Range {
            row_start: self.row_start.one_indexed(),
            row_end: self.row_end.one_indexed(),
            col_start: self.col_start.one_indexed(),
            col_end: self.col_end.one_indexed(),
        }
    }
}

#[cfg_attr(feature = "derive", derive(Serialize, Deserialize))]
#[cfg_attr(feature = "serialize-rustc", derive(RustcDecodable, RustcEncodable))]
#[derive(Debug, Hash, PartialEq, Eq, PartialOrd, Ord)]
pub struct Location<I: Indexed> {
    pub file: PathBuf,
    pub position: Position<I>,
}

impl<I: Indexed> Location<I> {
    pub fn new<F: Into<PathBuf>>(row: Row<I>, col: Column<I>, file: F) -> Location<I> {
        Location { position: Position { row, col }, file: file.into() }
    }

    pub fn from_position<F: Into<PathBuf>>(position: Position<I>, file: F) -> Location<I> {
        Location { position, file: file.into() }
    }
}

impl<I: Indexed> Clone for Location<I> {
    fn clone(&self) -> Location<I> {
        Location { position: self.position, file: self.file.clone() }
    }
}

impl Location<OneIndexed> {
    pub fn zero_indexed(&self) -> Location<ZeroIndexed> {
        Location { position: self.position.zero_indexed(), file: self.file.clone() }
    }
}

impl Location<ZeroIndexed> {
    pub fn one_indexed(&self) -> Location<OneIndexed> {
        Location { position: self.position.one_indexed(), file: self.file.clone() }
    }
}

#[cfg_attr(feature = "derive", derive(Serialize, Deserialize))]
#[cfg_attr(feature = "serialize-rustc", derive(RustcDecodable, RustcEncodable))]
#[derive(Debug, Hash, PartialEq, Eq, PartialOrd, Ord)]
pub struct Span<I: Indexed> {
    pub file: PathBuf,
    pub range: Range<I>,
}

impl<I: Indexed> Span<I> {
    pub fn new<F: Into<PathBuf>>(
        row_start: Row<I>,
        row_end: Row<I>,
        col_start: Column<I>,
        col_end: Column<I>,
        file: F,
    ) -> Span<I> {
        Span { range: Range { row_start, row_end, col_start, col_end }, file: file.into() }
    }

    pub fn from_range<F: Into<PathBuf>>(range: Range<I>, file: F) -> Span<I> {
        Span { range, file: file.into() }
    }

    pub fn from_positions<F: Into<PathBuf>>(
        start: Position<I>,
        end: Position<I>,
        file: F,
    ) -> Span<I> {
        Span { range: Range::from_positions(start, end), file: file.into() }
    }
}

impl<I: Indexed> Clone for Span<I> {
    fn clone(&self) -> Span<I> {
        Span { range: self.range, file: self.file.clone() }
    }
}

impl Span<OneIndexed> {
    pub fn zero_indexed(&self) -> Span<ZeroIndexed> {
        Span { range: self.range.zero_indexed(), file: self.file.clone() }
    }
}

impl Span<ZeroIndexed> {
    pub fn one_indexed(&self) -> Span<OneIndexed> {
        Span { range: self.range.one_indexed(), file: self.file.clone() }
    }
}

pub trait Indexed {}

#[cfg_attr(feature = "derive", derive(Serialize, Deserialize))]
#[cfg_attr(feature = "serialize-rustc", derive(RustcDecodable, RustcEncodable))]
#[derive(Hash, PartialEq, Eq, Debug, PartialOrd, Ord)]
pub struct ZeroIndexed;
impl Indexed for ZeroIndexed {}

#[cfg_attr(feature = "derive", derive(Serialize, Deserialize))]
#[cfg_attr(feature = "serialize-rustc", derive(RustcDecodable, RustcEncodable))]
#[derive(Hash, PartialEq, Eq, Debug, PartialOrd, Ord)]
pub struct OneIndexed;
impl Indexed for OneIndexed {}

#[cfg(feature = "nightly")]
#[cfg(test)]
mod test {
    use super::*;

    #[test]
    fn iter_row() {
        assert_eq!((Row::new_one_indexed(4)..Row::new_one_indexed(8)).count(), 4);
        assert_eq!(
            &*(Row::new_zero_indexed(0)..=Row::new_zero_indexed(8))
                .filter(|r| r.0 < 3)
                .map(|r| r.0)
                .collect::<Vec<_>>(),
            &[0, 1, 2],
        );
    }
}