diffshot 1.0.1

A tool to generate images from git diffs
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/// A single changed file in the diff
#[derive(Debug)]
pub struct FileDiff {
    pub filename : String,
    pub diff : Vec<Hunk>,
}

/// Continuous change block of changed lines in a file diff
#[derive(Debug)]
pub struct Hunk {
    pub header: String, // e.g. "@@ -10,6 +10,8 @@"
    pub lines: Vec<DiffLine>,
}

/// A single line in a hunk, with its type (added, removed, unchanged)
#[derive(Debug, Clone)]
pub struct DiffLine {
    pub content: String,
    pub line_type: LineType,
}

#[derive(Debug, Clone, PartialEq)]
pub enum LineType {
    Added,
    Removed,
    Unchanged,
    /// Git "\ No newline at end of file" marker - not a real source line.
    Metadata,
}



/// Parse raw unified diff output into structured FileDiff list
pub fn parse_diff(raw_diff: &str) -> Vec<FileDiff> {
    let mut file_diffs: Vec<FileDiff> = Vec::new();
    let mut current_file: Option<FileDiff> = None;
    let mut current_hunk: Option<Hunk> = None;

    for line in raw_diff.lines() {
        if line.starts_with("diff --git") {
            // flush hunk and file before starting a new one
            if let Some(hunk) = current_hunk.take() {
                if let Some(file) = &mut current_file {
                    file.diff.push(hunk);
                }
            }
            if let Some(file) = current_file.take() {
                file_diffs.push(file);
            }
            // Parse "diff --git a/<path> b/<path>" to seed filename immediately.
            // This handles deletions/renames where "+++ b/..." may never appear.
            let seeded_name = line
                .strip_prefix("diff --git ")
                .and_then(|rest| {
                    // rest is "a/<a_path> b/<b_path>"
                    let (a_part, b_part) = rest.split_once(" b/")?;
                    let b_path = b_part.trim();
                    if b_path == "/dev/null" || b_path.is_empty() {
                        // deletion: fall back to a/ path
                        a_part.strip_prefix("a/").map(|s| s.trim().to_string())
                    } else {
                        Some(b_path.to_string())
                    }
                })
                .unwrap_or_default();
            current_file = Some(FileDiff {
                filename: seeded_name,
                diff: Vec::new(),
            });
        } else if line.starts_with("+++ b/") {
            if let Some(file) = &mut current_file {
                file.filename = line.trim_start_matches("+++ b/").to_string();
            }
        } else if line.starts_with("@@") {
            if let Some(hunk) = current_hunk.take() {
                if let Some(file) = &mut current_file {
                    file.diff.push(hunk);
                }
            }
            current_hunk = Some(Hunk {
                header: line.to_string(),
                lines: Vec::new(),
            });
        } else if let Some(hunk) = &mut current_hunk {
            if line.starts_with("\\ No newline") {
                hunk.lines.push(DiffLine {
                    content: line.to_string(),
                    line_type: LineType::Metadata,
                });
            } else {
                let line_type = if line.starts_with('+') {
                    LineType::Added
                } else if line.starts_with('-') {
                    LineType::Removed
                } else {
                    LineType::Unchanged
                };
                hunk.lines.push(DiffLine {
                    content: if line.is_empty() { String::new() } else { line[1..].to_string() },
                    line_type,
                });
            }
        }
    }

    // Flush remaining hunk and file
    if let Some(hunk) = current_hunk.take() {
        if let Some(file) = &mut current_file {
            file.diff.push(hunk);
        }
    }
    if let Some(file) = current_file.take() {
        file_diffs.push(file);
    }

    file_diffs
}