refactor: add FASTQ header subtypes

src/fastq.rs

@@ -2,7 +2,11 @@ use crate::scramble_sequence;
 use std::fmt::Display;
 use std::str::FromStr;
 
-pub struct Header {
+pub enum Header {
+    Casava18(Casava18Header),
+}
+
+pub struct Casava18Header {
     instrument_name: String,
     run_id: u32,
     flowcell_id: String,
@@ -33,46 +37,55 @@ impl Header {
             ((value.len() as u8) + value.chars().map(|c| c as u8 & 2).sum::<u8>()) % 97
         }
 
-        Header {
-            instrument_name: format!("TEST{:0<2}", (string_sum(&self.instrument_name) * 17) % 97),
-            run_id: number(self.run_id),
-            flowcell_id: string(&self.flowcell_id),
-            flowcell_lane: number(self.flowcell_lane),
-            tile_number: number(self.tile_number),
-            x: self.x + string_sum(&self.instrument_name) as u32,
-            y: self.y + string_sum(&self.instrument_name) as u32,
-            pair_member: self.pair_member,
-            filtered: self.filtered,
-            control_bits: self.control_bits,
-            index_sequence: scramble_sequence(&self.index_sequence, 1),
+        match self {
+            Header::Casava18(header) => Header::Casava18(Casava18Header {
+                instrument_name: format!(
+                    "TEST{:0<2}",
+                    (string_sum(&header.instrument_name) * 17) % 97
+                ),
+                run_id: number(header.run_id),
+                flowcell_id: string(&header.flowcell_id),
+                flowcell_lane: number(header.flowcell_lane),
+                tile_number: number(header.tile_number),
+                x: header.x + string_sum(&header.instrument_name) as u32,
+                y: header.y + string_sum(&header.instrument_name) as u32,
+                pair_member: header.pair_member,
+                filtered: header.filtered,
+                control_bits: header.control_bits,
+                index_sequence: scramble_sequence(&header.index_sequence, 1),
+            }),
         }
     }
 }
 
 impl Display for Header {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Header::Casava18(header) => {
                 write!(
                     f,
                     "@{}:{}:{}:{}:{}:{}:{} {}:{}:{}:{}",
-            self.instrument_name,
-            self.run_id,
-            self.flowcell_id,
-            self.flowcell_lane,
-            self.tile_number,
-            self.x,
-            self.y,
-            match self.pair_member {
+                    header.instrument_name,
+                    header.run_id,
+                    header.flowcell_id,
+                    header.flowcell_lane,
+                    header.tile_number,
+                    header.x,
+                    header.y,
+                    match header.pair_member {
                         Pair::PairedEnd => "1",
                         Pair::MatePair => "2",
                     },
-            match self.filtered {
+                    match header.filtered {
                         Filtered::Y => "Y",
                         Filtered::N => "N",
                     },
-            self.control_bits,
-            self.index_sequence
+                    header.control_bits,
+                    header.index_sequence
                 )
             }
+        }
+    }
 }
 
 impl FromStr for Header {
@@ -80,18 +93,16 @@ impl FromStr for Header {
 
     fn from_str(s: &str) -> Result<Self, Self::Err> {
         if !s.starts_with("@") {
-            return Err("Invalid Casava 1.8+ header".to_string());
+            return Err("Cannot parse FASTQ header".to_string());
         }
 
         let parts = s
             .split(" ")
             .flat_map(|main_part| main_part.split(":").collect::<Vec<_>>())
             .collect::<Vec<_>>();
-        if parts.len() != 11 {
-            return Err("Invalid Casava 1.8+ header".to_string());
-        }
 
-        Ok(Header {
+        if parts.len() == 11 {
+            return Ok(Header::Casava18(Casava18Header {
                 instrument_name: parts[0][1..].to_string(),
                 run_id: parts[1]
                     .parse()
@@ -130,7 +141,10 @@ impl FromStr for Header {
                     return Err("Invalid Casava 1.8+ header".to_string());
                 },
                 index_sequence: parts[10].into(),
-        })
+            }));
+        }
+
+        Err("Cannot parse FASTQ header".to_string())
     }
 }
 
@@ -154,11 +168,8 @@ mod tests {
     #[test]
     fn should_return_parsed_header() {
         let given = "@EAS139:136:FC706VJ:2:2104:15343:197393 1:Y:18:ATCACG";
-        let actual = given.parse::<Header>();
 
-        assert!(actual.is_ok());
-
-        let actual = actual.unwrap();
+        if let Ok(Header::Casava18(actual)) = given.parse::<Header>() {
             assert_eq!(actual.instrument_name, "EAS139");
             assert_eq!(actual.run_id, 136);
             assert_eq!(actual.flowcell_id, "FC706VJ");
@@ -170,6 +181,9 @@ mod tests {
             assert_eq!(actual.filtered, Filtered::Y);
             assert_eq!(actual.control_bits, 18);
             assert_eq!(actual.index_sequence, "ATCACG");
+        } else {
+            panic!("Failed to parse FASTQ header");
+        }
     }
 
     #[test]