feat: Add Mercurial / hg support widgets

src/utils/terminal.ts

@@ -1,6 +1,12 @@
 import { execSync } from 'child_process';
 import * as fs from 'fs';
 import * as path from 'path';
+import { fileURLToPath } from 'url';
+import { dirname } from 'path';
+
+// ESM compatibility: __dirname is not available in ES modules
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = dirname(__filename);
 
 // Get package version
 // __PACKAGE_VERSION__ will be replaced at build time

src/utils/widgets.ts

@@ -12,6 +12,8 @@ const widgetRegistry = new Map<WidgetItemType, Widget>([
     ['git-branch', new widgets.GitBranchWidget()],
     ['git-changes', new widgets.GitChangesWidget()],
     ['git-worktree', new widgets.GitWorktreeWidget()],
+    ['hg-changes', new widgets.MercurialChangesWidget()],
+    ['hg-branch', new widgets.MercurialBranchWidget()],
     ['current-working-dir', new widgets.CurrentWorkingDirWidget()],
     ['tokens-input', new widgets.TokensInputWidget()],
     ['tokens-output', new widgets.TokensOutputWidget()],

src/widgets/MercurialBranch.ts

@@ -0,0 +1,84 @@
+import { execSync } from 'child_process';
+
+import type { RenderContext } from '../types/RenderContext';
+import type { Settings } from '../types/Settings';
+import type {
+    CustomKeybind,
+    Widget,
+    WidgetEditorDisplay,
+    WidgetItem
+} from '../types/Widget';
+
+export class MercurialBranchWidget implements Widget {
+    getDefaultColor(): string { return 'magenta'; }
+    getDescription(): string { return 'Shows the current Mercurial bookmark or commit description'; }
+    getDisplayName(): string { return 'Mercurial Branch'; }
+    getEditorDisplay(item: WidgetItem): WidgetEditorDisplay {
+        const hideNoHg = item.metadata?.hideNoHg === 'true';
+        const modifiers: string[] = [];
+
+        if (hideNoHg) {
+            modifiers.push('hide \'no hg\'');
+        }
+
+        return {
+            displayText: this.getDisplayName(),
+            modifierText: modifiers.length > 0 ? `(${modifiers.join(', ')})` : undefined
+        };
+    }
+
+    handleEditorAction(action: string, item: WidgetItem): WidgetItem | null {
+        if (action === 'toggle-nohg') {
+            const currentState = item.metadata?.hideNoHg === 'true';
+            return {
+                ...item,
+                metadata: {
+                    ...item.metadata,
+                    hideNoHg: (!currentState).toString()
+                }
+            };
+        }
+        return null;
+    }
+
+    render(item: WidgetItem, context: RenderContext, settings: Settings): string | null {
+        const hideNoHg = item.metadata?.hideNoHg === 'true';
+
+        if (context.isPreview) {
+            return item.rawValue ? 'default' : '⎇ default';
+        }
+
+        const branch = this.getMercurialBranch();
+        if (branch)
+            return item.rawValue ? branch : `⎇ ${branch}`;
+
+        return hideNoHg ? null : '⎇ no hg';
+    }
+
+    private getMercurialBranch(): string | null {
+        // Shows bookmark if available, otherwise first line of commit description
+        try {
+            const result = execSync('hg log -r . -T "{if(activebookmark, activebookmark, desc|firstline)}"', {
+                encoding: 'utf8',
+                stdio: ['pipe', 'pipe', 'ignore']
+            }).trim();
+
+            if (result) {
+                return result;
+            }
+        } catch {
+            // Not in a Mercurial repo or hg not available
+        }
+
+        return null;
+    }
+
+    getCustomKeybinds(): CustomKeybind[] {
+        return [
+            { key: 'h', label: '(h)ide \'no hg\' message', action: 'toggle-nohg' }
+        ];
+    }
+
+    supportsRawValue(): boolean { return true; }
+    supportsColors(item: WidgetItem): boolean { return true; }
+}

src/widgets/MercurialChanges.ts

@@ -0,0 +1,104 @@
+import { execSync } from 'child_process';
+
+import type { RenderContext } from '../types/RenderContext';
+import type { Settings } from '../types/Settings';
+import type {
+    CustomKeybind,
+    Widget,
+    WidgetEditorDisplay,
+    WidgetItem
+} from '../types/Widget';
+
+export class MercurialChangesWidget implements Widget {
+    getDefaultColor(): string { return 'yellow'; }
+    getDescription(): string { return 'Shows Mercurial changes count (+insertions, -deletions)'; }
+    getDisplayName(): string { return 'Mercurial Changes'; }
+    getEditorDisplay(item: WidgetItem): WidgetEditorDisplay {
+        const hideNoHg = item.metadata?.hideNoHg === 'true';
+        const modifiers: string[] = [];
+
+        if (hideNoHg) {
+            modifiers.push('hide \'no hg\'');
+        }
+
+        return {
+            displayText: this.getDisplayName(),
+            modifierText: modifiers.length > 0 ? `(${modifiers.join(', ')})` : undefined
+        };
+    }
+
+    handleEditorAction(action: string, item: WidgetItem): WidgetItem | null {
+        if (action === 'toggle-nohg') {
+            const currentState = item.metadata?.hideNoHg === 'true';
+            return {
+                ...item,
+                metadata: {
+                    ...item.metadata,
+                    hideNoHg: (!currentState).toString()
+                }
+            };
+        }
+        return null;
+    }
+
+    render(item: WidgetItem, context: RenderContext, settings: Settings): string | null {
+        const hideNoHg = item.metadata?.hideNoHg === 'true';
+
+        if (context.isPreview) {
+            return '(+42,-10)';
+        }
+
+        const changes = this.getMercurialChanges();
+        if (changes)
+            return `(+${changes.insertions},-${changes.deletions})`;
+        else
+            return hideNoHg ? null : '(no hg)';
+    }
+
+    private getMercurialChanges(): { insertions: number; deletions: number } | null {
+        // hg diff --stat outputs a summary line like:
+        // "1 files changed, 16 insertions(+), 8 deletions(-)"
+        try {
+            const diffStat = execSync('hg diff --stat 2>/dev/null | tail -1', {
+                encoding: 'utf8',
+                stdio: ['pipe', 'pipe', 'ignore'],
+                shell: '/bin/sh'
+            }).trim();
+
+            if (diffStat && diffStat.includes('changed')) {
+                return this.parseDiffStat(diffStat);
+            }
+        } catch {
+            // Not in a Mercurial repo or hg not available
+        }
+
+        return null;
+    }
+
+    private parseDiffStat(stat: string): { insertions: number; deletions: number } {
+        let insertions = 0;
+        let deletions = 0;
+
+        // Match patterns like "16 insertions(+)" or "8 deletions(-)"
+        const insertMatch = /(\d+) insertion/.exec(stat);
+        const deleteMatch = /(\d+) deletion/.exec(stat);
+
+        if (insertMatch?.[1]) {
+            insertions = parseInt(insertMatch[1], 10);
+        }
+        if (deleteMatch?.[1]) {
+            deletions = parseInt(deleteMatch[1], 10);
+        }
+
+        return { insertions, deletions };
+    }
+
+    getCustomKeybinds(): CustomKeybind[] {
+        return [
+            { key: 'h', label: '(h)ide \'no hg\' message', action: 'toggle-nohg' }
+        ];
+    }
+
+    supportsRawValue(): boolean { return false; }
+    supportsColors(item: WidgetItem): boolean { return true; }
+}

src/widgets/index.ts

@@ -3,6 +3,8 @@ export { OutputStyleWidget } from './OutputStyle';
 export { GitBranchWidget } from './GitBranch';
 export { GitChangesWidget } from './GitChanges';
 export { GitWorktreeWidget } from './GitWorktree';
+export { MercurialChangesWidget } from './MercurialChanges';
+export { MercurialBranchWidget } from './MercurialBranch';
 export { TokensInputWidget } from './TokensInput';
 export { TokensOutputWidget } from './TokensOutput';
 export { TokensCachedWidget } from './TokensCached';