feat: add history script (#175)

This adds a JS script which produces a JSON object with information
about which colors have been added/removed/modified on what dates.

Authored-by: Nicolas Mattia <nicolas@android-cdbbbac25dcac6d7.localdomain>

scripts/tools/history.js

@@ -0,0 +1,66 @@
+const child_process = require("child_process");
+const readline = require("readline");
+
+function cmd(c) {
+  const stdout = child_process.execSync(c);
+  return stdout.toString().trim();
+}
+
+// Print the list of colors added/removed/changed by date.
+// Pretty inefficient due to the many git commands (optimized for clarity)
+async function main() {
+
+  // Grab the list of all git commits
+  const allCommits = cmd("git log --pretty=format:%h").split("\n").filter(Boolean);
+
+  // The data, one element for each commit (date)
+  const dat = [];
+
+  for (const commit of allCommits) {
+
+    // Figure out what changed in that particular commit
+    const diff = cmd(`git show ${commit} -- ./src/colornames.csv`)
+      .split("\n").filter(Boolean);
+
+    // Grab the date for said commit
+    const dt = cmd(`git show -s ${commit} --format=%ci`);
+
+    // The list of color modified (indexed by hex value) with "op" (+/-/~)
+    const modified = {};
+
+    for(const line of diff) {
+      const res = line.match(/^((?<op>(\+|-)))(?<name>[^,]+),(?<hex>[^,]+)/)
+      if(!res) { continue; }
+      const name = res.groups?.name;
+      const hex = res.groups?.hex;
+      var op = res.groups?.op;
+
+      // If a value already introduced with a different op, then it's
+      // a modification
+      if(modified[hex] && modified[hex].op !== op) { op = "~" }
+
+      modified[hex] = { hex, name, op };
+    }
+
+    // Partition by added/removed/changed
+
+    const added = Object.values(modified)
+      .filter(x => x.op === "+")
+      .map(({name, hex}) => ({ name, hex }));
+
+    const removed = Object.values(modified)
+      .filter(x => x.op === "-")
+      .map(({name, hex}) => ({ name, hex }));
+
+    const changed = Object.values(modified)
+      .filter(x => x.op === "~")
+      .map(({name, hex}) => ({ name, hex }));
+
+    // Add the day
+    dat.push({ date: dt, added, removed, changed });
+  }
+
+  console.log(JSON.stringify(dat));
+}
+
+main()