subx_cli/core/formats/
ass.rs

1//! Advanced SubStation Alpha (ASS/SSA) subtitle format implementation.
2//!
3//! This module provides parsing, serialization, and detection capabilities
4//! for the ASS/SSA subtitle format, including style and color definitions.
5//!
6//! # Examples
7//!
8//! ```rust,no_run
9//! use subx_cli::core::formats::{SubtitleFormat, ass::AssFormat};
10//! let ass = AssFormat;
11//! let content = "[Events]\nFormat: Layer,Start,End,Style,Name,MarginL,MarginR,MarginV,Effect,Text\nDialogue: 0,0:00:01.00,0:00:02.50,Default,,0000,0000,0000,,Hello";
12//! let subtitle = ass.parse(content).unwrap();
13//! ```
14
15use crate::Result;
16use crate::core::formats::{
17    Subtitle, SubtitleEntry, SubtitleFormat, SubtitleFormatType, SubtitleMetadata,
18};
19use crate::error::SubXError;
20use std::time::Duration;
21
22/// ASS style definition for subtitle entries.
23#[derive(Debug, Clone)]
24pub struct AssStyle {
25    /// Name identifier for this style
26    pub name: String,
27    /// Font family name to use for rendering
28    pub font_name: String,
29    /// Font size in points
30    pub font_size: u32,
31    /// Primary text color
32    pub primary_color: Color,
33    /// Secondary text color for styling effects
34    pub secondary_color: Color,
35    /// Outline border color
36    pub outline_color: Color,
37    /// Shadow color for text depth effect
38    pub shadow_color: Color,
39    /// Whether text should be rendered in bold
40    pub bold: bool,
41    /// Whether text should be rendered in italic
42    pub italic: bool,
43    /// Whether text should be underlined
44    pub underline: bool,
45    /// Text alignment value (1-9 for numpad positions)
46    pub alignment: i32,
47}
48
49/// ASS color structure for style entries.
50#[derive(Debug, Clone)]
51pub struct Color {
52    /// Red component (0-255)
53    pub r: u8,
54    /// Green component (0-255)
55    pub g: u8,
56    /// Blue component (0-255)
57    pub b: u8,
58}
59
60impl Color {
61    /// Creates a white color (RGB: 255, 255, 255).
62    pub fn white() -> Self {
63        Color {
64            r: 255,
65            g: 255,
66            b: 255,
67        }
68    }
69
70    /// Creates a black color (RGB: 0, 0, 0).
71    pub fn black() -> Self {
72        Color { r: 0, g: 0, b: 0 }
73    }
74
75    /// Creates a red color (RGB: 255, 0, 0).
76    pub fn red() -> Self {
77        Color { r: 255, g: 0, b: 0 }
78    }
79}
80
81/// Subtitle format implementation for ASS/SSA.
82///
83/// The `AssFormat` struct implements parsing, serialization, and detection
84/// for the ASS/SSA subtitle format.
85pub struct AssFormat;
86
87impl SubtitleFormat for AssFormat {
88    fn parse(&self, content: &str) -> Result<Subtitle> {
89        let mut entries = Vec::new();
90        let mut in_events = false;
91        let mut fields: Vec<&str> = Vec::new();
92        for line in content.lines() {
93            let l = line.trim_start();
94            if l.eq_ignore_ascii_case("[events]") {
95                in_events = true;
96                continue;
97            }
98            if !in_events {
99                continue;
100            }
101            if l.to_lowercase().starts_with("format:") {
102                fields = l["Format:".len()..].split(',').map(|s| s.trim()).collect();
103                continue;
104            }
105            if l.to_lowercase().starts_with("dialogue:") {
106                let data = l["Dialogue:".len()..].trim();
107                let parts: Vec<&str> = data.splitn(fields.len(), ',').collect();
108                if parts.len() < fields.len() {
109                    continue;
110                }
111                let start_index = fields
112                    .iter()
113                    .position(|&f| f.eq_ignore_ascii_case("start"))
114                    .ok_or_else(|| {
115                        SubXError::subtitle_format(
116                            "ASS",
117                            "Missing 'Start' field in Format declaration",
118                        )
119                    })?;
120                let end_index = fields
121                    .iter()
122                    .position(|&f| f.eq_ignore_ascii_case("end"))
123                    .ok_or_else(|| {
124                        SubXError::subtitle_format(
125                            "ASS",
126                            "Missing 'End' field in Format declaration",
127                        )
128                    })?;
129                let text_index = fields
130                    .iter()
131                    .position(|&f| f.eq_ignore_ascii_case("text"))
132                    .ok_or_else(|| {
133                        SubXError::subtitle_format(
134                            "ASS",
135                            "Missing 'Text' field in Format declaration",
136                        )
137                    })?;
138                let start = parts[start_index].trim();
139                let end = parts[end_index].trim();
140                let text = parts[text_index..].join(",").replace("\\N", "\n");
141                let start_time = parse_ass_time(start)?;
142                let end_time = parse_ass_time(end)?;
143                entries.push(SubtitleEntry {
144                    index: entries.len() + 1,
145                    start_time,
146                    end_time,
147                    text,
148                    styling: None,
149                });
150            }
151        }
152        Ok(Subtitle {
153            entries,
154            metadata: SubtitleMetadata {
155                title: None,
156                language: None,
157                encoding: "utf-8".to_string(),
158                frame_rate: None,
159                original_format: SubtitleFormatType::Ass,
160            },
161            format: SubtitleFormatType::Ass,
162        })
163    }
164
165    fn serialize(&self, subtitle: &Subtitle) -> Result<String> {
166        let mut output = String::new();
167        output.push_str("[Script Info]\n");
168        output.push_str("; Script generated by SubX\n");
169        output.push_str("ScriptType: v4.00+\n\n");
170        output.push_str("[V4+ Styles]\n");
171        output.push_str("Format: Name,Fontname,Fontsize,PrimaryColour,SecondaryColour,OutlineColour,BackColour,Bold,Italic,Underline,StrikeOut,ScaleX,ScaleY,Spacing,Angle,BorderStyle,Outline,Shadow,Alignment,MarginL,MarginR,MarginV,Encoding\n");
172        output.push_str("Style: Default,Arial,20,&H00FFFFFF,&H000000FF,&H00000000,&H00000000,0,0,0,0,100,100,0,0,1,2,0,2,10,10,10,1\n\n");
173        output.push_str("[Events]\n");
174        output.push_str("Format: Layer,Start,End,Style,Name,MarginL,MarginR,MarginV,Effect,Text\n");
175        for entry in &subtitle.entries {
176            let text = entry.text.replace('\n', "\\N");
177            let start = format_ass_time(entry.start_time);
178            let end = format_ass_time(entry.end_time);
179            output.push_str(&format!(
180                "Dialogue: 0,{},{},Default,,0000,0000,0000,,{}\n",
181                start, end, text
182            ));
183        }
184        Ok(output)
185    }
186
187    fn detect(&self, content: &str) -> bool {
188        content.contains("[Script Info]") || content.contains("Dialogue:")
189    }
190
191    fn format_name(&self) -> &'static str {
192        "ASS"
193    }
194
195    fn file_extensions(&self) -> &'static [&'static str] {
196        &["ass", "ssa"]
197    }
198}
199
200#[cfg(test)]
201mod tests {
202    use super::*;
203
204    const SAMPLE_ASS: &str = "[Script Info]\nScriptType: v4.00+\n\n[V4+ Styles]\nFormat: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text\n\n[Events]\nFormat: Layer,Start,End,Style,Name,MarginL,MarginR,MarginV,Effect,Text\nDialogue: 0,0:00:01.00,0:00:02.50,Default,,0000,0000,0000,,Hello\\NASS\n";
205
206    #[test]
207    fn test_detect_ass() {
208        let fmt = AssFormat;
209        assert!(fmt.detect(SAMPLE_ASS));
210        assert!(!fmt.detect("Not ASS content"));
211    }
212
213    #[test]
214    fn test_parse_ass_and_serialize() {
215        let fmt = AssFormat;
216        let subtitle = fmt.parse(SAMPLE_ASS).expect("ASS parse failed");
217        assert_eq!(subtitle.entries.len(), 1);
218        assert_eq!(subtitle.entries[0].text, "Hello\nASS");
219        let out = fmt.serialize(&subtitle).expect("ASS serialize failed");
220        assert!(out.contains("Dialogue: 0,0:00:01.00,0:00:02.50"));
221        assert!(out.contains("Hello\\NASS"));
222    }
223
224    #[test]
225    fn test_parse_ass_missing_start_field() {
226        let fmt = AssFormat;
227        // Format line omits the Start field.
228        let content = "[Events]\nFormat: Layer,End,Style,Name,MarginL,MarginR,MarginV,Effect,Text\nDialogue: 0,0:00:02.50,Default,,0000,0000,0000,,Hi\n";
229        let err = fmt.parse(content).expect_err("missing Start must error");
230        let msg = err.to_string();
231        assert!(msg.contains("Start"), "unexpected error: {}", msg);
232    }
233
234    #[test]
235    fn test_parse_ass_missing_end_field() {
236        let fmt = AssFormat;
237        let content = "[Events]\nFormat: Layer,Start,Style,Name,MarginL,MarginR,MarginV,Effect,Text\nDialogue: 0,0:00:01.00,Default,,0000,0000,0000,,Hi\n";
238        let err = fmt.parse(content).expect_err("missing End must error");
239        assert!(err.to_string().contains("End"));
240    }
241
242    #[test]
243    fn test_parse_ass_missing_text_field() {
244        let fmt = AssFormat;
245        let content = "[Events]\nFormat: Layer,Start,End,Style,Name,MarginL,MarginR,MarginV,Effect\nDialogue: 0,0:00:01.00,0:00:02.50,Default,,0000,0000,0000,\n";
246        let err = fmt.parse(content).expect_err("missing Text must error");
247        assert!(err.to_string().contains("Text"));
248    }
249
250    #[test]
251    fn test_parse_ass_time_overflow() {
252        // Hours value near u64::MAX to force checked_mul overflow.
253        let overflow_time = format!("{}:00:00.00", u64::MAX);
254        let err = parse_ass_time(&overflow_time).expect_err("overflow must be detected");
255        assert!(err.to_string().to_lowercase().contains("overflow"));
256    }
257
258    #[test]
259    fn test_parse_ass_time_valid() {
260        let d = parse_ass_time("1:02:03.45").expect("valid time");
261        assert_eq!(
262            d,
263            Duration::from_millis(3_600_000 + 2 * 60_000 + 3 * 1000 + 450)
264        );
265    }
266}
267
268fn parse_ass_time(time: &str) -> Result<Duration> {
269    let parts: Vec<&str> = time.split(&[':', '.'][..]).collect();
270    if parts.len() != 4 {
271        return Err(SubXError::subtitle_format(
272            "ASS",
273            format!("Invalid time format: {}", time),
274        ));
275    }
276    let hours: u64 = parts[0]
277        .parse()
278        .map_err(|e: std::num::ParseIntError| SubXError::subtitle_format("ASS", e.to_string()))?;
279    let minutes: u64 = parts[1]
280        .parse()
281        .map_err(|e: std::num::ParseIntError| SubXError::subtitle_format("ASS", e.to_string()))?;
282    let seconds: u64 = parts[2]
283        .parse()
284        .map_err(|e: std::num::ParseIntError| SubXError::subtitle_format("ASS", e.to_string()))?;
285    let centi: u64 = parts[3]
286        .parse()
287        .map_err(|e: std::num::ParseIntError| SubXError::subtitle_format("ASS", e.to_string()))?;
288
289    let overflow =
290        || SubXError::subtitle_format("ASS", format!("Timestamp arithmetic overflow: {}", time));
291    let total_ms = hours
292        .checked_mul(3_600_000)
293        .ok_or_else(overflow)?
294        .checked_add(minutes.checked_mul(60_000).ok_or_else(overflow)?)
295        .ok_or_else(overflow)?
296        .checked_add(seconds.checked_mul(1_000).ok_or_else(overflow)?)
297        .ok_or_else(overflow)?
298        .checked_add(centi.checked_mul(10).ok_or_else(overflow)?)
299        .ok_or_else(overflow)?;
300    Ok(Duration::from_millis(total_ms))
301}
302
303fn format_ass_time(duration: Duration) -> String {
304    let total_ms = duration.as_millis();
305    let hours = total_ms / 3600000;
306    let minutes = (total_ms % 3600000) / 60000;
307    let seconds = (total_ms % 60000) / 1000;
308    let centi = (total_ms % 1000) / 10;
309    format!("{}:{:02}:{:02}.{:02}", hours, minutes, seconds, centi)
310}
subx_cli/core/formats/ass.rs

subx_cli/core/formats/
ass.rs
