From c535cfa081828049537e415ed93905128abb6795 Mon Sep 17 00:00:00 2001
From: Kelvin Oghenerhoro Omereshone <kelvinomereshone@gmail.com>
Date: Wed, 11 Sep 2024 16:43:24 +0100
Subject: [PATCH] feat: implement go to policy

---
 .../go-to-definitions/go-to-policy.js         | 90 +++++++++++++++++++
 packages/language-server/index.js             | 12 ++-
 2 files changed, 98 insertions(+), 4 deletions(-)
 create mode 100644 packages/language-server/go-to-definitions/go-to-policy.js

diff --git a/packages/language-server/go-to-definitions/go-to-policy.js b/packages/language-server/go-to-definitions/go-to-policy.js
new file mode 100644
index 0000000..a2524dc
--- /dev/null
+++ b/packages/language-server/go-to-definitions/go-to-policy.js
@@ -0,0 +1,90 @@
+const lsp = require('vscode-languageserver/node')
+const path = require('path')
+const fs = require('fs').promises
+
+module.exports = async function goToPolicy(document, position) {
+  const fileName = path.basename(document.uri)
+
+  if (fileName !== 'policies.js') {
+    return null
+  }
+
+  const policyInfo = extractPolicyInfo(document, position)
+
+  if (!policyInfo) {
+    return null
+  }
+
+  const projectRoot = path.dirname(path.dirname(document.uri))
+  const fullPolicyPath = resolvePolicyPath(projectRoot, policyInfo.policy)
+
+  if (await fileExists(fullPolicyPath)) {
+    return lsp.Location.create(fullPolicyPath, lsp.Range.create(0, 0, 0, 0))
+  }
+
+  return null
+}
+
+function extractPolicyInfo(document, position) {
+  const text = document.getText()
+  const offset = document.offsetAt(position)
+
+  // This regex matches policy definitions, including arrays of policies and boolean values
+  const regex =
+    /(['"])((?:\*|[\w-]+(?:\/\*?)?))?\1\s*:\s*((?:\[?\s*(?:(?:['"][\w-]+['"](?:\s*,\s*)?)+)\s*\]?)|true|false)/g
+  let match
+
+  while ((match = regex.exec(text)) !== null) {
+    const [fullMatch, , route, policiesOrBoolean] = match
+    const start = match.index
+    const end = start + fullMatch.length
+
+    // Check if the cursor is anywhere within the entire match
+    if (start <= offset && offset <= end) {
+      // If policiesOrBoolean is a boolean, ignore it
+      if (policiesOrBoolean === true || policiesOrBoolean === false) {
+        continue
+      }
+
+      // Remove brackets if present and split into individual policies
+      const policies = policiesOrBoolean
+        .replace(/^\[|\]$/g, '')
+        .split(',')
+        .map((p) => p.trim().replace(/^['"]|['"]$/g, ''))
+
+      // Find which policy the cursor is on
+      let currentStart = start + fullMatch.indexOf(policiesOrBoolean)
+      for (const policy of policies) {
+        const policyStart = text.indexOf(policy, currentStart)
+        const policyEnd = policyStart + policy.length
+
+        if (offset >= policyStart && offset <= policyEnd) {
+          return {
+            policy,
+            range: lsp.Range.create(
+              document.positionAt(policyStart),
+              document.positionAt(policyEnd)
+            )
+          }
+        }
+
+        currentStart = policyEnd
+      }
+    }
+  }
+
+  return null
+}
+
+function resolvePolicyPath(projectRoot, policyPath) {
+  return path.join(projectRoot, 'api', 'policies', `${policyPath}.js`)
+}
+
+async function fileExists(filePath) {
+  try {
+    await fs.access(new URL(filePath))
+    return true
+  } catch {
+    return false
+  }
+}
diff --git a/packages/language-server/index.js b/packages/language-server/index.js
index 1eb1175..6c02b82 100644
--- a/packages/language-server/index.js
+++ b/packages/language-server/index.js
@@ -2,6 +2,7 @@ const lsp = require('vscode-languageserver/node')
 const TextDocument = require('vscode-languageserver-textdocument').TextDocument
 const validateDocument = require('./validators/validate-document')
 const goToAction = require('./go-to-definitions/go-to-action')
+const goToPolicy = require('./go-to-definitions/go-to-policy')
 
 const connection = lsp.createConnection(lsp.ProposedFeatures.all)
 const documents = new lsp.TextDocuments(TextDocument)
@@ -32,10 +33,13 @@ connection.onDefinition(async (params) => {
   if (!document) {
     return null
   }
-  const definitions = []
-  const actionDefinitions = await goToAction(document, params.position)
-  definitions.push(actionDefinitions)
-  return definitions || null
+
+  const actionDefinition = await goToAction(document, params.position)
+  const policyDefinition = await goToPolicy(document, params.position)
+
+  const definitions = [actionDefinition, policyDefinition].filter(Boolean)
+
+  return definitions.length > 0 ? definitions : null
 })
 
 documents.listen(connection)