From c3ac916c32ded33c30082ea5de7693e28ca939a4 Mon Sep 17 00:00:00 2001
From: Scott Chacon <schacon@gmail.com>
Date: Mon, 6 May 2024 15:30:38 +0200
Subject: [PATCH] link to cross-repo unified diff on github

---
 .../lib/components/ProjectSetupTarget.svelte  |  4 +-
 app/src/lib/vbranches/types.ts                | 51 ++++++++++++++++---
 2 files changed, 45 insertions(+), 10 deletions(-)

diff --git a/app/src/lib/components/ProjectSetupTarget.svelte b/app/src/lib/components/ProjectSetupTarget.svelte
index b1a22b28f..7d8057d80 100644
--- a/app/src/lib/components/ProjectSetupTarget.svelte
+++ b/app/src/lib/components/ProjectSetupTarget.svelte
@@ -109,8 +109,8 @@
 					</SelectItem>
 				</Select>
 				<p class="project-setup__description-text text-base-body-12">
-					You have branches from multiple remotes. If you want to specify a push target for creating
-					branches that is different from your production branch, change it here.
+					You have branches from multiple remotes. If you want to specify a remote for creating
+					branches that is different from the remote that your target branch is on, change it here.
 				</p>
 			</div>
 		{/if}
diff --git a/app/src/lib/vbranches/types.ts b/app/src/lib/vbranches/types.ts
index 146e1b2ec..c72fd40d1 100644
--- a/app/src/lib/vbranches/types.ts
+++ b/app/src/lib/vbranches/types.ts
@@ -347,23 +347,32 @@ export class BaseBranch {
 		return this.lastFetchedMs ? new Date(this.lastFetchedMs) : undefined;
 	}
 
+	get pushRepoBaseUrl(): string {
+		return this.cleanUrl(this.pushRemoteUrl);
+	}
+
 	get repoBaseUrl(): string {
-		if (this.pushRemoteUrl.startsWith('http')) {
-			return this.pushRemoteUrl.replace('.git', '');
+		return this.cleanUrl(this.remoteUrl);
+	}
+
+	// turn a git remote url into a web url (github, gitlab, bitbucket, etc)
+	private cleanUrl(url: string): string {
+		if (url.startsWith('http')) {
+			return url.replace('.git', '').trim();
 		} else {
-			return this.pushRemoteUrl.replace(':', '/').replace('git@', 'https://').replace('.git', '');
+			return url.replace(':', '/').replace('git@', 'https://').replace('.git', '').trim();
 		}
 	}
 
 	commitUrl(commitId: string): string | undefined {
 		// Different Git providers use different paths for the commit url:
 		if (this.isBitBucket) {
-			return `${this.repoBaseUrl}/commits/${commitId}`;
+			return `${this.pushRepoBaseUrl}/commits/${commitId}`;
 		}
 		if (this.isGitlab) {
-			return `${this.repoBaseUrl}/-/commit/${commitId}`;
+			return `${this.pushRepoBaseUrl}/-/commit/${commitId}`;
 		}
-		return `${this.repoBaseUrl}/commit/${commitId}`;
+		return `${this.pushRepoBaseUrl}/commit/${commitId}`;
 	}
 
 	get shortName() {
@@ -374,11 +383,37 @@ export class BaseBranch {
 		if (!upstreamBranchName) return undefined;
 		const baseBranchName = this.branchName.split('/')[1];
 		const branchName = upstreamBranchName.split('/').slice(3).join('/');
+
+		if (this.pushRemoteName) {
+			if (this.isGitHub) {
+				// master...schacon:docs:Virtual-branch
+				const pushUsername = this.extractUsernameFromGitHubUrl(this.pushRemoteUrl);
+				const pushRepoName = this.extractRepoNameFromGitHubUrl(this.pushRemoteUrl);
+				return `${this.repoBaseUrl}/compare/${baseBranchName}...${pushUsername}:${pushRepoName}:${branchName}`;
+			}
+		}
+
 		if (this.isBitBucket) {
-			return `${this.repoBaseUrl.trim()}/branch/${branchName}?dest=${baseBranchName}`;
+			return `${this.repoBaseUrl}/branch/${branchName}?dest=${baseBranchName}`;
 		}
 		// The following branch path is good for at least Gitlab and Github:
-		return `${this.repoBaseUrl.trim()}/compare/${baseBranchName}...${branchName}`;
+		return `${this.repoBaseUrl}/compare/${baseBranchName}...${branchName}`;
+	}
+
+	private extractUsernameFromGitHubUrl(url: string): string | null {
+		const regex = /github\.com[/:]([a-zA-Z0-9_-]+)\/.*/;
+		const match = url.match(regex);
+		return match ? match[1] : null;
+	}
+
+	private extractRepoNameFromGitHubUrl(url: string): string | null {
+		const regex = /github\.com[/:]([a-zA-Z0-9_-]+)\/([a-zA-Z0-9_-]+)/;
+		const match = url.match(regex);
+		return match ? match[2] : null;
+	}
+
+	private get isGitHub(): boolean {
+		return this.repoBaseUrl.includes('github.com');
 	}
 
 	private get isBitBucket(): boolean {