use nom::{AsBytes, IResult, InputLength, InputTake};

use super::{
    combinator::GreenElement,
    cookie::cookie_node,
    emphasis::{bold_node, code_node, italic_node, strike_node, underline_node, verbatim_node},
    fn_ref::fn_ref_node,
    inline_call::inline_call_node,
    inline_src::inline_src_node,
    input::Input,
    link::link_node,
    macros::macros_node,
    radio_target::radio_target_node,
    snippet::snippet_node,
    target::target_node,
    timestamp::{timestamp_active_node, timestamp_diary_node, timestamp_inactive_node},
};

pub struct InlinePositions<'a> {
    bytes: &'a [u8],
    pos: usize,
    next: Option<usize>,
}

impl InlinePositions<'_> {
    pub fn new(bytes: &[u8]) -> InlinePositions {
        InlinePositions {
            bytes,
            pos: 0,
            next: Some(0),
        }
    }
}

impl Iterator for InlinePositions<'_> {
    type Item = usize;

    fn next(&mut self) -> Option<Self::Item> {
        self.next.take().or_else(|| {
            jetscii::bytes!(b'@', b'<', b'[', b' ', b'(', b'{', b'\'', b'"', b'\n')
                .find(&self.bytes[self.pos..])
                .map(|i| {
                    self.pos += i + 1;

                    match self.bytes[self.pos - 1] {
                        b'{' => {
                            self.next = Some(self.pos);
                            self.pos - 1
                        }
                        b' ' | b'(' | b'\'' | b'"' | b'\n' => self.pos,
                        _ => self.pos - 1,
                    }
                })
        })
    }
}

pub fn object_nodes(input: Input) -> Vec<GreenElement> {
    // debug_assert!(!input.is_empty());
    let nodes = object_nodes_base(input);
    debug_assert_eq!(
        input.as_str(),
        nodes.iter().fold(String::new(), |s, i| s + &i.to_string()),
        "parser must be lossless"
    );
    nodes
}

fn object_nodes_base(input: Input) -> Vec<GreenElement> {
    let mut children = vec![];

    let mut i = input;
    'l: loop {
        for (input, head) in InlinePositions::new(i.as_bytes()).map(|idx| i.take_split(idx)) {
            if let Ok((input, node)) = object_node(input) {
                if !head.is_empty() {
                    children.push(head.text_token())
                }
                children.push(node);
                i = input;
                continue 'l;
            }
        }

        break;
    }

    if !i.is_empty() {
        children.push(i.text_token());
    }

    children
}

fn object_node(i: Input) -> IResult<Input, GreenElement, ()> {
    if i.input_len() < 3 {
        return Err(nom::Err::Error(()));
    }

    match &i.as_bytes()[0] {
        b'*' => bold_node(i),
        b'+' => strike_node(i),
        b'/' => italic_node(i),
        b'_' => underline_node(i),
        b'=' => verbatim_node(i),
        b'~' => code_node(i),
        b'@' => snippet_node(i),
        b'{' => macros_node(i),
        b'<' => radio_target_node(i)
            .or_else(|_| target_node(i))
            .or_else(|_| timestamp_diary_node(i))
            .or_else(|_| timestamp_active_node(i)),
        b'[' => cookie_node(i)
            .or_else(|_| link_node(i))
            .or_else(|_| fn_ref_node(i))
            .or_else(|_| timestamp_inactive_node(i)),
        b'c' => inline_call_node(i),
        b's' => inline_src_node(i),
        _ => Err(nom::Err::Error(())),
    }
}

#[test]
fn parse() {
    use crate::{
        syntax::{combinator::node, SyntaxKind, SyntaxNode},
        ParseConfig,
    };

    let t = |input: &str| {
        let config = &ParseConfig::default();
        let children = object_nodes((input, config).into());
        SyntaxNode::new_root(node(SyntaxKind::PARAGRAPH, children).into_node().unwrap())
    };

    insta::assert_debug_snapshot!(
        t("~org-inlinetask-min-level~[fn:oiml:The default value of \n~org-inlinetask-min-level~ is =15=.]"),
        @r###"
    PARAGRAPH@0..93
      CODE@0..26
        TILDE@0..1 "~"
        TEXT@1..25 "org-inlinetask-min-level"
        TILDE@25..26 "~"
      FN_REF@26..93
        L_BRACKET@26..27 "["
        TEXT@27..29 "fn"
        COLON@29..30 ":"
        TEXT@30..34 "oiml"
        COLON@34..35 ":"
        TEXT@35..57 "The default value of \n"
        CODE@57..83
          TILDE@57..58 "~"
          TEXT@58..82 "org-inlinetask-min-level"
          TILDE@82..83 "~"
        TEXT@83..87 " is "
        VERBATIM@87..91
          EQUAL@87..88 "="
          TEXT@88..90 "15"
          EQUAL@90..91 "="
        TEXT@91..92 "."
        R_BRACKET@92..93 "]"
    "###
    );

    insta::assert_debug_snapshot!(
      t(r#"Org is a /plaintext markup syntax/ developed with *Emacs* in 2003.
The canonical parser is =org-element.el=, which provides a number of
functions starting with ~org-element-~."#),
      @r###"
    PARAGRAPH@0..175
      TEXT@0..9 "Org is a "
      ITALIC@9..34
        SLASH@9..10 "/"
        TEXT@10..33 "plaintext markup syntax"
        SLASH@33..34 "/"
      TEXT@34..50 " developed with "
      BOLD@50..57
        STAR@50..51 "*"
        TEXT@51..56 "Emacs"
        STAR@56..57 "*"
      TEXT@57..91 " in 2003.\nThe canonic ..."
      VERBATIM@91..107
        EQUAL@91..92 "="
        TEXT@92..106 "org-element.el"
        EQUAL@106..107 "="
      TEXT@107..160 ", which provides a nu ..."
      CODE@160..174
        TILDE@160..161 "~"
        TEXT@161..173 "org-element-"
        TILDE@173..174 "~"
      TEXT@174..175 "."
    "###
    );
}