From 812740ee367e98fceeab0b1690268653fb4b9e27 Mon Sep 17 00:00:00 2001
From: bergi <bergi@axolotlfarm.org>
Date: Mon, 30 Oct 2023 22:47:49 +0100
Subject: [PATCH] feat: Added .base method

---
 Grapoi.js                      | 20 ++++++++++++++
 lib/base.js                    | 50 ++++++++++++++++++++++++++++++++++
 test/Grapoi.test.js            | 45 ++++++++++++++++++++++++++++++
 test/support/datasets.multi.js | 27 ++++++++++++++++++
 4 files changed, 142 insertions(+)
 create mode 100644 lib/base.js

diff --git a/Grapoi.js b/Grapoi.js
index f986477..c0aeda3 100644
--- a/Grapoi.js
+++ b/Grapoi.js
@@ -1,3 +1,4 @@
+import { baseDataset, baseTerm } from './lib/base.js'
 import { rebaseDataset } from './lib/rebase.js'
 import { replaceDataset } from './lib/replace.js'
 import sortByScore from './lib/sortByScore.js'
@@ -96,6 +97,25 @@ class Grapoi extends PathList {
     return super.addOut(this._toTermArray(predicates), this._toTermArray(objects), callback)
   }
 
+  /**
+   * Base all terms with a relative IRI with the given base.
+   * @param {Grapoi|Grapoi[]|Term|Term[]} base Base of the terms
+   * @returns {Constructor} Instance with a single pointer with the term based
+   */
+  base (base) {
+    if (!base) {
+      throw new Error('base parameter is required')
+    }
+
+    base = this._toTerm(base)
+
+    for (const ptr of this.ptrs) {
+      baseDataset(base, { factory: this.factory })(ptr.dataset)
+    }
+
+    return this.node(baseTerm(base, { factory: this.factory })(this.term))
+  }
+
   /**
    * Use the given score function on all pointers and return the pointer with the best score.
    * @param {function} score Score function
diff --git a/lib/base.js b/lib/base.js
new file mode 100644
index 0000000..3827bd0
--- /dev/null
+++ b/lib/base.js
@@ -0,0 +1,50 @@
+function baseDataset (newBaseTerm, { factory }) {
+  const base = baseQuad(newBaseTerm, { factory })
+
+  return dataset => {
+    for (const quad of [...dataset]) {
+      const newQuad = base(quad)
+
+      if (newQuad !== quad) {
+        dataset.delete(quad)
+        dataset.add(newQuad)
+      }
+    }
+  }
+}
+
+function baseQuad (newBaseTerm, { factory }) {
+  const base = baseTerm(newBaseTerm, { factory })
+
+  return quad => {
+    const subject = base(quad.subject)
+    const predicate = base(quad.predicate)
+    const object = base(quad.object)
+
+    if (subject === quad.subject && predicate === quad.predicate && object === quad.object) {
+      return quad
+    }
+
+    return factory.quad(subject, predicate, object, quad.graph)
+  }
+}
+
+function baseTerm (newBaseTerm, { factory }) {
+  return term => {
+    if (term.termType !== 'NamedNode') {
+      return term
+    }
+
+    if (/[a-z]+:\/\//.test(term.value)) {
+      return term
+    }
+
+    return factory.namedNode(new URL(term.value, newBaseTerm.value).toString())
+  }
+}
+
+export {
+  baseDataset,
+  baseQuad,
+  baseTerm
+}
diff --git a/test/Grapoi.test.js b/test/Grapoi.test.js
index c4f91c8..83330c2 100644
--- a/test/Grapoi.test.js
+++ b/test/Grapoi.test.js
@@ -277,6 +277,51 @@ describe('Grapoi', () => {
     })
   })
 
+  describe('.base', () => {
+    it('should be a method', () => {
+      const { grapoi } = datasets.default()
+
+      strictEqual(typeof grapoi.base, 'function')
+    })
+
+    it('should throw an error if no base is given', () => {
+      const { grapoi } = datasets.default()
+
+      throws(() => {
+        grapoi.base()
+      }, {
+        message: 'base parameter is required'
+      })
+    })
+
+    it('should return a new Grapoi object', () => {
+      const { expectedTerm, grapoi } = datasets.base()
+
+      const result = grapoi.base(expectedTerm)
+
+      strictEqual(result instanceof Grapoi, true)
+      notStrictEqual(result, grapoi)
+    })
+
+    it('should base the dateset', () => {
+      const { expectedGrapoi, expectedTerm, grapoi } = datasets.base()
+
+      const result = grapoi.base(expectedTerm)
+
+      grapoiEqual(result, expectedGrapoi)
+      datasetEqual(result.dataset, expectedGrapoi.dataset)
+    })
+
+    it('should support base argument given as ptr', () => {
+      const { expectedGrapoi, grapoi } = datasets.base()
+
+      const result = grapoi.base(expectedGrapoi)
+
+      grapoiEqual(result, expectedGrapoi)
+      datasetEqual(result.dataset, expectedGrapoi.dataset)
+    })
+  })
+
   describe('.best', () => {
     it('should be a method', () => {
       const { grapoi } = datasets.default()
diff --git a/test/support/datasets.multi.js b/test/support/datasets.multi.js
index 2566c9f..104e608 100644
--- a/test/support/datasets.multi.js
+++ b/test/support/datasets.multi.js
@@ -26,6 +26,20 @@ terms.graphs = [ns.ex.graph1, ns.ex.graph2]
 
 const triples = {}
 
+triples.base = [
+  [factory.namedNode(''), factory.namedNode('/propertyA'), links[0]],
+  [links[0], factory.namedNode('/propertyB'), factory.namedNode('/end')],
+  [ns.other(''), ns.other.propertyA, links[1]],
+  [links[1], ns.other.propertyB, ns.other.end]
+]
+
+triples.based = [
+  [ns.ex(''), ns.ex.propertyA, links[0]],
+  [links[0], ns.ex.propertyB, ns.ex.end],
+  [ns.other(''), ns.other.propertyA, links[1]],
+  [links[1], ns.other.propertyB, ns.other.end]
+]
+
 triples.in = [
   [ns.ex.end1, ns.ex.propertyA, ns.ex.start1],
   [ns.ex.end1, ns.ex.propertyA, ns.ex.start2],
@@ -371,6 +385,19 @@ multi.any = () => {
   return createPathListDataset([], { terms: [null] })
 }
 
+multi.base = () => {
+  const { ...others } = createPathListDataset(triples.base, { terms: [ns.ex('')] })
+
+  const expectedTerm = ns.ex('')
+
+  const expectedGrapoi = new Grapoi({
+    dataset: factory.dataset(triples.based.map(parts => factory.quad(...parts))),
+    term: expectedTerm
+  })
+
+  return { expectedGrapoi, expectedTerm, ...others }
+}
+
 multi.best = () => {
   const { dataset, ...others } = createPathListDataset(triples.inBlankNode, {
     subjects: [ns.ex.start1, ns.ex.start1]