ass-core 0.1.2

High-performance ASS subtitle format parser and analyzer
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

//! Rule implementation for detecting undefined style references.
//!
//! Houses the [`MissingStyleRule`] type and its [`LintRule`] implementation,
//! which scans events for style names not defined in the styles section.

use crate::{
    analysis::{
        linting::{IssueCategory, IssueSeverity, LintIssue, LintRule},
        ScriptAnalysis,
    },
    parser::Section,
};
use alloc::{format, vec::Vec};

/// Rule for detecting events that reference undefined styles
///
/// Events must reference valid style names defined in the [V4+ Styles] section.
/// Missing style references cause renderers to fall back to default styling,
/// which may not match the intended visual appearance.
///
/// # Performance
///
/// - Time complexity: O(n + m) for n styles and m events
/// - Memory: O(n) for style name collection
/// - Target: <1ms for typical scripts with 100 styles and 1000 events
///
/// # Example
///
/// ```rust
/// use ass_core::analysis::linting::rules::missing_style::MissingStyleRule;
/// use ass_core::analysis::linting::LintRule;
/// use ass_core::{Script, ScriptAnalysis};
///
/// let script = Script::parse(r#"
/// [V4+ Styles]
/// Format: Name, Fontname, Fontsize, PrimaryColour, SecondaryColour, OutlineColour, BackColour, Bold, Italic, Underline, StrikeOut, ScaleX, ScaleY, Spacing, Angle, BorderStyle, Outline, Shadow, Alignment, MarginL, MarginR, MarginV, Encoding
/// Style: Default,Arial,20,&H00FFFFFF&,&H000000FF&,&H00000000&,&H00000000&,0,0,0,0,100,100,0,0,1,2,0,2,10,10,10,1
///
/// [Events]
/// Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
/// Dialogue: 0,0:00:00.00,0:00:05.00,Undefined,,0,0,0,,Text with undefined style
/// "#)?;
///
/// let analysis = ScriptAnalysis::analyze(&script)?;
/// let rule = MissingStyleRule;
/// let issues = rule.check_script(&analysis);
/// assert!(!issues.is_empty()); // Should detect the missing style reference
/// # Ok::<(), Box<dyn std::error::Error>>(())
/// ```
pub struct MissingStyleRule;

impl LintRule for MissingStyleRule {
    fn id(&self) -> &'static str {
        "missing-style"
    }

    fn name(&self) -> &'static str {
        "Missing Style"
    }

    fn description(&self) -> &'static str {
        "Detects events referencing non-existent styles"
    }

    fn default_severity(&self) -> IssueSeverity {
        IssueSeverity::Error
    }

    fn category(&self) -> IssueCategory {
        IssueCategory::Styling
    }

    fn check_script(&self, analysis: &ScriptAnalysis) -> Vec<LintIssue> {
        let mut issues = Vec::new();

        let style_names: Vec<&str> = analysis
            .resolved_styles()
            .iter()
            .map(|style| style.name)
            .collect();

        if let Some(Section::Events(events)) = analysis
            .script()
            .sections()
            .iter()
            .find(|s| matches!(s, Section::Events(_)))
        {
            for event in events {
                if !style_names.contains(&event.style) {
                    let issue = LintIssue::new(
                        self.default_severity(),
                        IssueCategory::Styling,
                        self.id(),
                        format!("Event references undefined style: {}", event.style),
                    )
                    .with_suggested_fix(format!(
                        "Define style '{}' or use an existing style",
                        event.style
                    ));

                    issues.push(issue);
                }
            }
        }

        issues
    }
}