feat: fish autocomplete

Signed-off-by: loks0n <[email protected]>

Author: loks0n

packages/auto-complete/src/commands.ts

@@ -25,6 +25,13 @@ export const installCommand = buildCommand({
                 optional: true,
                 placeholder: "command",
             },
+            fish: {
+                kind: "parsed",
+                brief: "Command executed by fish to generate completion proposals",
+                parse: String,
+                optional: true,
+                placeholder: "command",
+            },
         },
         positional: {
             kind: "tuple",
@@ -67,6 +74,11 @@ export const uninstallCommand = buildCommand({
                 brief: "Uninstall autocompletion for bash",
                 optional: true,
             },
+            fish: {
+                kind: "boolean",
+                brief: "Uninstall autocompletion for fish",
+                optional: true,
+            },
         },
         positional: {
             kind: "tuple",

packages/auto-complete/src/impl.ts

@@ -2,13 +2,14 @@
 // Distributed under the terms of the Apache 2.0 license.
 import type { StricliAutoCompleteContext } from "./context";
 import { forBash } from "./shells/bash";
+import { forFish } from "./shells/fish";
 
 export interface ShellManager {
     readonly install: (targetCommand: string, autocompleteCommand: string) => Promise<void>;
     readonly uninstall: (targetCommand: string) => Promise<void>;
 }
 
-export type Shell = "bash";
+export type Shell = "bash" | "fish";
 
 export type ShellAutoCompleteCommands = Readonly<Partial<Record<Shell, string>>>;
 
@@ -21,6 +22,10 @@ export async function install(
         const bash = await forBash(this);
         await bash?.install(targetCommand, flags.bash);
     }
+    if (flags.fish) {
+        const fish = await forFish(this);
+        await fish?.install(targetCommand, flags.fish);
+    }
 }
 
 export type ActiveShells = Readonly<Partial<Record<Shell, boolean>>>;
@@ -34,4 +39,8 @@ export async function uninstall(
         const shellManager = await forBash(this);
         await shellManager?.uninstall(targetCommand);
     }
+    if (flags.fish) {
+        const shellManager = await forFish(this);
+        await shellManager?.uninstall(targetCommand);
+    }
 }

packages/auto-complete/src/shells/fish.ts

@@ -0,0 +1,80 @@
+// Copyright 2024 Bloomberg Finance L.P.
+// Distributed under the terms of the Apache 2.0 license.
+import type { StricliAutoCompleteContext } from "../context";
+import type { ShellManager } from "../impl";
+import nodeOs from "node:os";
+import nodeFs from "node:fs";
+import nodePath from "node:path";
+
+function getFilePath(targetCommand: string, completionsDir: string): string {
+    return nodePath.join(completionsDir, `${targetCommand}.fish`);
+}
+
+const BLOCK_START_LINE = (targetCommand: string) =>
+    `# @stricli/auto-complete START [${targetCommand}]`;
+const BLOCK_END_LINE = "# @stricli/auto-complete END";
+
+export async function forFish(
+    context: StricliAutoCompleteContext
+): Promise<ShellManager | undefined> {
+    const { os = nodeOs, fs = nodeFs, path = nodePath } = context;
+    if (!context.process.env["SHELL"]?.includes("fish")) {
+        context.process.stderr.write(`Skipping fish as shell was not detected.\n`);
+        return;
+    }
+    const home = os.homedir();
+    const completionsDir = path.join(home, ".config", "fish", "completions");
+    try {
+        await fs.promises.mkdir(completionsDir, { recursive: true });
+    } catch {
+        context.process.stderr.write(
+            `Could not create fish completions directory at ${completionsDir}.\n`
+        );
+        return;
+    }
+    return {
+        install: async (targetCommand: string, autocompleteCommand: string) => {
+            const filePath = getFilePath(targetCommand, completionsDir);
+            const functionName = `__fish_${targetCommand}_complete`;
+            // Create a fish completions file that defines a helper function and registers it.
+            const fileContent = [
+                BLOCK_START_LINE(targetCommand),
+                `function ${functionName}`,
+                `    # Get the current command line (as a single string)`,
+                `    set -l cmd (commandline -cp)`,
+                `    # Invoke the provided autocomplete command with the command line`,
+                `    set -l completions ( ${autocompleteCommand} $cmd )`,
+                `    for comp in $completions`,
+                `        echo $comp`,
+                `    end`,
+                `end`,
+                `complete -c ${targetCommand} -f -a "(${functionName})"`,
+                BLOCK_END_LINE,
+                "",
+            ].join("\n");
+            try {
+                await fs.promises.writeFile(filePath, fileContent);
+                context.process.stdout.write(
+                    `Fish completions installed to ${filePath}. Restart fish shell or run 'source ${filePath}' to load changes.\n`
+                );
+            } catch {
+                context.process.stderr.write(
+                    `Failed to write fish completions file at ${filePath}.\n`
+                );
+            }
+        },
+        uninstall: async (targetCommand: string) => {
+            const filePath = getFilePath(targetCommand, completionsDir);
+            try {
+                await fs.promises.unlink(filePath);
+                context.process.stdout.write(
+                    `Fish completions removed from ${filePath}. Restart fish shell or run 'source ${filePath}' to update changes.\n`
+                );
+            } catch {
+                context.process.stderr.write(
+                    `Could not remove fish completions file at ${filePath}.\n`
+                );
+            }
+        },
+    };
+}