Work on merge setup

Author: mre

src/lib.rs

@@ -13,9 +13,11 @@
 )]
 
 mod git;
+mod merge;
 mod parser;
 mod quartiles;
 mod types;
 
 pub use crate::git::count_commits;
+pub use crate::merge::Merger;
 pub use crate::parser::Parser;

src/merge.rs

@@ -0,0 +1,82 @@
+use std::convert::TryFrom;
+
+use crate::{parser::ParseState, types::Timeline};
+use anyhow::Result;
+
+/// Merger merges multiple timelines into one
+#[derive(Debug)]
+pub struct Merger {
+    state: ParseState,
+}
+
+impl Merger {
+    /// Create a new merger with a clean state (no timeline merged)
+    pub fn new() -> Self {
+        let state = ParseState::default();
+        Merger { state }
+    }
+
+    fn merge_single(&mut self, single: ParseState) -> Result<()> {
+        self.state = single;
+        Ok(())
+    }
+
+    /// Merge multiple timelines together into one
+    /// This is helpful when analyzing multiple repositories and trying to combine
+    /// the individual results.
+    pub fn merge(&mut self, timelines: &[Timeline]) -> Result<Timeline> {
+        for timeline in timelines {
+            let single = ParseState::try_from(timeline.clone())?;
+            self.merge_single(single)?;
+        }
+        Ok(Timeline::try_from(&self.state)?)
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    use crate::types::{Contribution, Range, Year};
+
+    #[test]
+    fn test_merge_none() {
+        let mut merger = Merger::new();
+        assert_eq!(merger.merge(&[]).unwrap(), Timeline::default());
+    }
+
+    #[test]
+    fn test_merge_one() {
+        let mut timeline = Timeline::default();
+
+        let year = "2020".into();
+        let total = 1234;
+        let range = Range {
+            start: "2020-02-01".into(),
+            end: "2020-03-02".into(),
+        };
+
+        let year1 = Year { year, total, range };
+        let years = vec![year1];
+        timeline.years = years;
+
+        let contributions = vec![
+            Contribution {
+                date: "2020-01-01".into(),
+                count: 1000,
+                color: "".into(),
+                intensity: 4,
+            },
+            Contribution {
+                date: "2020-01-02".into(),
+                count: 234,
+                color: "".into(),
+                intensity: 4,
+            },
+        ];
+
+        timeline.contributions = contributions;
+
+        let mut merger = Merger::new();
+        assert_eq!(merger.merge(&[timeline.clone()]).unwrap(), timeline);
+    }
+}