From 3fda8fd4110b28f143bebaacd32a071a1fc893fc Mon Sep 17 00:00:00 2001
From: Seb Aebischer <s.aebischer@comicrelief.com>
Date: Sun, 7 May 2023 12:42:22 +0100
Subject: [PATCH] feat(text): `deleteBlock`, `deleteEveryBlock`

---
 src/text.ts        | 65 ++++++++++++++++++++++++++++++++++++++++++++++
 tests/text.spec.ts | 41 +++++++++++++++++++++++++++++
 2 files changed, 106 insertions(+)

diff --git a/src/text.ts b/src/text.ts
index da6dfd1..0967e3b 100644
--- a/src/text.ts
+++ b/src/text.ts
@@ -160,4 +160,69 @@ export class Text {
     });
     this.content = lines.join('\n');
   }
+
+  /**
+   * Deletes the first group of lines that match `block`, or throws if no lines
+   * match.
+   *
+   * @param block Strings or RegExps that identify the lines.
+   */
+  deleteBlock(block: (string | RegExp)[]) {
+    if (block.length === 0) {
+      return;
+    }
+
+    const lines = this.lines();
+    const patterns = block.map((it) => regex(it));
+    const maxIndex = lines.length - block.length;
+    const row = lines.findIndex((
+      (_, index) => index <= maxIndex && patterns.every((
+        (pattern, offset) => lines[index + offset].match(pattern)
+      ))
+    ));
+    if (row === -1) {
+      throw new Error(`No block found matching\n\n${patterns.join('\n')}`);
+    }
+    lines.splice(row, block.length);
+    this.content = lines.join('\n');
+  }
+
+  /**
+   * Deletes every group of lines that matches `block`.
+   *
+   * @param block Strings or RegExps that identify the lines.
+   */
+  deleteEveryBlock(block: (string | RegExp)[]) {
+    if (block.length === 0) {
+      return;
+    }
+
+    const lines = this.lines();
+    const patterns = block.map((it) => regex(it));
+    const rows: number[] = [];
+    let matchRow = -1;
+    let matches = 0;
+    lines.forEach((line, index) => {
+      if (line.match(patterns[matches])) {
+        if (matches === 0) {
+          matchRow = index;
+        }
+        matches += 1;
+        if (matches === block.length) {
+          rows.push(matchRow);
+          matches = 0;
+        }
+      } else if (matches > 0) {
+        if (line.match(patterns[0])) {
+          matches = 1;
+        } else {
+          matches = 0;
+        }
+      }
+    });
+    rows.forEach((row, index) => {
+      lines.splice(row - index * block.length, block.length);
+    });
+    this.content = lines.join('\n');
+  }
 }
diff --git a/tests/text.spec.ts b/tests/text.spec.ts
index bc49785..4289492 100644
--- a/tests/text.spec.ts
+++ b/tests/text.spec.ts
@@ -213,4 +213,45 @@ describe('Text', () => {
       expect(text.content).to.equal('one');
     });
   });
+
+  describe('deleteBlock', () => {
+    it('should delete the first matching block (strings)', () => {
+      const text = new Text('one\ntwo\n\none\nthree\n\none\ntwo');
+      text.deleteBlock(['one', 'two']);
+      expect(text.content).to.equal('\none\nthree\n\none\ntwo');
+    });
+
+    it('should delete the first matching block (regexps)', () => {
+      const text = new Text('one\ntwo\n\none\nthree\n\none\ntwo');
+      text.deleteBlock([/one/, /two/]);
+      expect(text.content).to.equal('\none\nthree\n\none\ntwo');
+    });
+
+    it('should throw if no block matches', () => {
+      const text = new Text('one');
+      expect(
+        () => text.deleteBlock(['one', 'two']),
+      ).to.throw('No block found matching\n\n/one/\n/two/');
+    });
+  });
+
+  describe('deleteEveryBlock', () => {
+    it('should delete all matching blocks (strings)', () => {
+      const text = new Text('one\ntwo\n\none\nthree\n\none\ntwo');
+      text.deleteEveryBlock(['one', 'two']);
+      expect(text.content).to.equal('\none\nthree\n');
+    });
+
+    it('should delete all matching blocks (regexps)', () => {
+      const text = new Text('one\ntwo\n\none\nthree\n\none\ntwo');
+      text.deleteEveryBlock([/one/, /two/]);
+      expect(text.content).to.equal('\none\nthree\n');
+    });
+
+    it('should not consider lines overlapping in blocks that match', () => {
+      const text = new Text('one\none\none\ntwo');
+      text.deleteEveryBlock(['one', 'one']);
+      expect(text.content).to.equal('one\ntwo');
+    });
+  });
 });