yog-book 0.65.0

In-game book/documentation framework for Yog mods (Patchouli-like).
Documentation 
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

//! Per-book navigation state.

use crate::Book;

/// Max entries shown on the first list spread (right page only).
pub const ENTRIES_FIRST: usize = 10;
/// Max entries shown on each subsequent list spread (right page only).
pub const ENTRIES_PER: usize = 12;

#[derive(Debug, Clone)]
pub struct BookViewState {
    pub cat: usize,
    pub entry: usize, // absolute index within entries_in_cat
    pub page: usize,
    pub at_home: bool,
    pub list_spread: usize, // which page of the entry list we're on
}

impl Default for BookViewState {
    fn default() -> Self {
        Self {
            cat: 0,
            entry: 0,
            page: 0,
            at_home: true,
            list_spread: 0,
        }
    }
}

impl BookViewState {
    /// Handle a navigation event string. Returns true if state changed.
    pub fn handle(&mut self, ev: &str, book: &Book) -> bool {
        if ev == "home" {
            if !self.at_home {
                self.at_home = true;
                return true;
            }
        } else if let Some(n) = ev.strip_prefix("cat:") {
            if let Ok(i) = n.parse::<usize>()
                && i < book.categories.len()
            {
                let changed = self.at_home || i != self.cat;
                self.cat = i;
                self.entry = 0;
                self.page = 0;
                self.list_spread = 0;
                self.at_home = false;
                return changed;
            }
        } else if let Some(n) = ev.strip_prefix("entry:") {
            // N is the absolute index within entries_in_cat.
            if let Ok(i) = n.parse::<usize>() {
                let total = self.entries_in_cat(book).len();
                if i < total && (i != self.entry || self.page != 0) {
                    self.entry = i;
                    self.page = 0;
                    return true;
                }
            }
        } else if ev == "prev_page" {
            if self.page > 0 {
                self.page -= 1;
                return true;
            }
        } else if ev == "next_page" {
            if self.page + 1 < self.page_count(book) {
                self.page += 1;
                return true;
            }
        } else if ev == "prev_list" {
            if self.list_spread > 0 {
                self.list_spread -= 1;
                return true;
            }
        } else if ev == "next_list" && self.list_spread + 1 < self.list_spread_count(book) {
            self.list_spread += 1;
            return true;
        }
        false
    }

    /// All entries in the current category, unfiltered.
    pub fn entries_in_cat<'b>(&self, book: &'b Book) -> Vec<&'b crate::BookEntry> {
        let cat_id = book
            .categories
            .get(self.cat)
            .map(|c| c.id.as_str())
            .unwrap_or("");
        book.entries
            .iter()
            .filter(|e| e.category == cat_id)
            .collect()
    }

    /// How many list spreads the current category needs.
    pub fn list_spread_count(&self, book: &Book) -> usize {
        let total = self.entries_in_cat(book).len();
        if total <= ENTRIES_FIRST {
            return 1;
        }
        1 + (total - ENTRIES_FIRST).div_ceil(ENTRIES_PER)
    }

    /// Absolute index of the first entry on the current list spread.
    pub fn list_spread_start(&self) -> usize {
        if self.list_spread == 0 {
            0
        } else {
            ENTRIES_FIRST + (self.list_spread - 1) * ENTRIES_PER
        }
    }

    /// The slice of entries visible on the current list spread.
    pub fn entries_visible<'b>(&self, book: &'b Book) -> Vec<&'b crate::BookEntry> {
        let all = self.entries_in_cat(book);
        let start = self.list_spread_start();
        let count = if self.list_spread == 0 {
            ENTRIES_FIRST
        } else {
            ENTRIES_PER
        };
        all.into_iter().skip(start).take(count).collect()
    }

    pub fn current_entry<'b>(&self, book: &'b Book) -> Option<&'b crate::BookEntry> {
        self.entries_in_cat(book).into_iter().nth(self.entry)
    }

    pub fn page_count(&self, book: &Book) -> usize {
        self.current_entry(book)
            .map(|e| e.pages.len().max(1))
            .unwrap_or(1)
    }
}