1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159

use std::fmt::{self, Display, Formatter, Write};

use crate::OutlineStructure;

const EXTRA_INDENT_WIDTH: usize = 1;

#[derive(Debug, Clone, Default)]
pub struct Outline {
    pub text: Option<String>,
    pub sub_outlines: Vec<Outline>,
}

impl Outline {
    #[inline]
    pub fn parse_html<S: AsRef<str>>(html: S, max_depth: usize) -> Outline {
        OutlineStructure::parse_html(html, max_depth).into()
    }
}

impl From<OutlineStructure> for Outline {
    #[inline]
    fn from(os: OutlineStructure) -> Self {
        if os.sectioning_type.is_heading() {
            Outline {
                text: os.heading.map(|heading| heading.into()),
                sub_outlines: Vec::new(),
            }
        } else {
            let mut sub_outlines = Vec::new();

            let mut stack = vec![];
            let mut levels: Vec<u8> = vec![];

            for sub_os in os.sub_outline_structures.into_iter().rev() {
                if sub_os.sectioning_type.is_heading() {
                    let heading = sub_os.heading.unwrap();
                    let heading_level = heading.get_start_level();

                    let mut outline = Outline {
                        text: Some(heading.into()),
                        sub_outlines: Vec::new(),
                    };

                    while let Some(level) = levels.pop() {
                        if level > heading_level {
                            outline.sub_outlines.push(stack.pop().unwrap());
                        } else {
                            levels.push(level);

                            break;
                        }
                    }

                    levels.push(heading_level);
                    stack.push(outline);
                } else {
                    stack.push(sub_os.into());
                }
            }

            let text = if let Some(heading) = os.heading {
                let heading_level = heading.get_start_level();

                let need_flatten = {
                    let mut b = false;

                    for level in levels.iter().copied().rev() {
                        if level >= heading_level {
                            b = true;
                        }
                    }

                    b
                };

                if need_flatten {
                    let mut outline = Outline {
                        text: Some(heading.into()),
                        sub_outlines: Vec::new(),
                    };

                    while let Some(level) = levels.pop() {
                        if level > heading_level {
                            outline.sub_outlines.push(stack.pop().unwrap());
                        } else {
                            levels.push(level);

                            break;
                        }
                    }

                    levels.push(heading_level);
                    stack.push(outline);

                    None
                } else {
                    Some(heading.into())
                }
            } else if os.sectioning_type.is_sectioning_content_type() {
                Some(format!("Untitled {}", os.sectioning_type.as_str()))
            } else {
                None
            };

            while let Some(sub_os) = stack.pop() {
                sub_outlines.push(sub_os);
            }

            Outline {
                text,
                sub_outlines,
            }
        }
    }
}

impl Display for Outline {
    #[inline]
    fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), fmt::Error> {
        format(f, self, 1, 0)
    }
}

fn format(
    f: &mut Formatter<'_>,
    outline: &Outline,
    number: usize,
    indent: usize,
) -> Result<(), fmt::Error> {
    let new_ident = if let Some(text) = outline.text.as_ref() {
        if indent > 0 {
            f.write_char('\n')?;

            for _ in 0..indent {
                f.write_char(' ')?;
            }
        } else if number > 1 {
            f.write_char('\n')?;
        }

        f.write_fmt(format_args!("{}. ", number))?;
        f.write_str(text.as_str())?;

        indent + count_digit(outline.sub_outlines.len()) + 2 + EXTRA_INDENT_WIDTH
    } else {
        indent
    };

    for (i, sub_outline) in outline.sub_outlines.iter().enumerate() {
        format(f, sub_outline, i + 1, new_ident)?;
    }

    Ok(())
}

#[inline]
fn count_digit(n: usize) -> usize {
    (n as f64).log10().floor() as usize + 1
}