tea --magic=install; tea --magic=uninstall

README.md

@@ -16,7 +16,7 @@
 </p>
 
 
-# tea/cli 0.38.4
+# tea/cli 0.39.0
 
 `tea` is [`npx`] for *everything*.
 
@@ -30,9 +30,12 @@ $ brew install teaxyz/pkgs/tea-cli
 $ tea node --version
 v19.7.0
 
+$ tea node@16 --version
+v16.20.1
+
 $ node
 command not found: node
-# ^^ tea is not a package manager; keep installing shit w/brew
+# ^^ tea is not a package manager; if you need installs, keep using brew
 ```
 
 [`npx`]: https://www.npmjs.com/package/npx
@@ -54,6 +57,7 @@ v16.20.1
 
 $ source <(tea --env)
 # temporarily adds `my-project`’s deps to your current shell
+# install our “shell magic” to do this automatically (read on for docs)
 
 $ node --version
 v16.20.1
@@ -77,7 +81,8 @@ This works for everything. eg. `pyproject.toml`, `.ruby-version`, etc.
 
 > <details><summary><i>PSA:</i> Stop using Docker</summary><br>
 >
-> Docker is great for deployment and cross compilation, but… let’s face it: it
+> Look, don’t *stop* using Docker—that’s not what we mean.
+> Docker is great for deployment, but… let’s face it: it
 > sucks for dev.
 >
 > *Docker stifles builders*.
@@ -173,8 +178,9 @@ $ tea \
 
 ## Shell Magic
 
-If you’re cool and you love cool stuff then `tea` can optionally make command
-not found errors a thing of the past:
+Every README for every project has 10 pages of “how to install x” commands.
+With `tea`’s magic you can just copy and paste the usage instructions and skip
+the install instructions.
 
 ```sh
 $ which node
@@ -216,6 +222,18 @@ $ node
 command not found: node
 ```
 
+### Installing Shell Magic
+
+If you want shell magic when your terminal loads, install it:
+
+```sh
+$ tea --magic=install
+# installs a one-liner to your ~/.shellrc
+
+$ tea --magic=uninstall
+# nps if you change your mind
+```
+
 &nbsp;
 
 
@@ -235,17 +253,15 @@ sudo install -m 755 \
   /usr/local/bin/tea
 ```
 
-## Setting up Magic
-
-By itself tea works well, it’s just somewhat manual, but we’re all magic
-addicts and recommend it:
+Once installed you can install our shell magic:
 
 ```sh
-echo 'source <(tea --magic)' >> ~/.zshrc
+tea --magic=install
 ```
 
-With magic stepping into directories ensures the packages those projects need
+* Stepping into directories ensures the packages those projects need
 are installed on demand and available to the tools you’re using.
+* Commands you type just work without package management nonsense.
 
 &nbsp;
 

src/app.magic.ts

@@ -176,3 +176,89 @@ export default function(self: Path, shell?: string) {
       throw new TeaError("unsupported shell", {shell})
   }
 }
+
+import { readLines } from "deno/io/read_lines.ts"
+import { readAll } from "deno/streams/read_all.ts"
+import { writeAll } from "deno/streams/write_all.ts"
+import { flatmap } from "tea/utils/misc.ts";
+
+
+//TODO could be a fun efficiency excercise to maintain a separate write file-pointer
+//TODO assumes unix line-endings
+export async function install_magic(op: 'install' | 'uninstall') {
+  let opd_at_least_once = false
+  const encode = (() => { const e = new TextEncoder(); return e.encode.bind(e) })()
+
+  here: for (const [file, line] of shells()) {
+    const fd = await Deno.open(file.string, {read: true, write: true})
+    try {
+      let pos = 0
+      for await (const readline of readLines(fd)) {
+        if (readline.trim() == line) {
+          if (op == 'install') {
+            console.info("magic already installed:", file)
+            continue here
+          } else if (op == 'uninstall') {
+            // we have to seek because readLines is buffered and thus the seek pos is probs already at the file end
+            fd.seek(pos + readline.length + 1, Deno.SeekMode.Start)
+            const rest = await readAll(fd)
+
+            await fd.truncate(pos)  // deno has no way I can find to truncate from the current seek position
+            fd.seek(pos, Deno.SeekMode.Start)
+            await writeAll(fd, rest)
+
+            opd_at_least_once = true
+            console.info("removed magic:", file)
+
+            continue here
+          }
+        }
+
+        pos += readline.length + 1  // the +1 is because readLines() truncates it
+      }
+
+      if (op == 'install') {
+        const byte = new Uint8Array(1)
+        fd.seek(0, Deno.SeekMode.End)  // potentially the above didn't reach the end
+        while (true) {
+          fd.seek(-1, Deno.SeekMode.Current)
+          await fd.read(byte)
+          if (byte[0] != 10) break
+          fd.seek(-1, Deno.SeekMode.Current)
+        }
+
+        await writeAll(fd, encode(`\n\n${line}\n`))
+
+        console.info("magic installed:", file)
+      }
+    } finally {
+      fd.close()
+    }
+  }
+
+  if (op == 'uninstall' && !opd_at_least_once) {
+    console.info("magic already not installed")
+  }
+}
+
+function shells(): [Path, string][] {
+  const zdotdir = flatmap(Deno.env.get("ZDOTDIR"), Path.abs) ?? Path.home()
+  const fishdir = flatmap(Deno.env.get("XDG_CONFIG_HOME"), Path.abs) ?? Path.home().join(".config")
+
+  const std = (shell: string) => `source <(tea --magic=${shell})  #docs.tea.xyz/magic`
+
+  const candidates: [Path, string][] = [
+    [zdotdir.join(".zshrc"), std("zsh")],
+    [Path.home().join(".bashrc"), 'source /dev/stdin <<<"$(tea --magic=bash)  #docs.tea.xyz/magic'],
+    [Path.home().join(".config/elvish/rc.elv"), std("elvish")],
+    [fishdir.join("fish/config.fish"), "tea --magic=fish | source  #docs.tea.xyz/magic"],
+  ]
+
+  const viable_candidates = candidates.filter(([file]) => file.exists())
+
+  if (viable_candidates.length == 0) {
+    throw new TeaError("no shell rc files found to install magic into")
+  }
+
+  return viable_candidates
+}

src/app.main.ts

@@ -8,7 +8,7 @@ import complete from "./app.complete.ts"
 import provides from "./app.provides.ts"
 import setup from "./prefab/setup.ts"
 const { useSync, usePantry } = hooks
-import magic from "./app.magic.ts"
+import magic, { install_magic } from "./app.magic.ts"
 import dump from "./app.dump.ts"
 import help from "./app.help.ts"
 import { Args } from "./args.ts"
@@ -112,7 +112,14 @@ export async function run(args: Args) {
     await complete(args.complete)
     break
   default:
-    await print(magic(execPath, args.mode[1]))
+    switch (args.mode[1]) {
+    case 'install':
+    case 'uninstall':
+      install_magic(args.mode[1])
+      break
+    default:
+      await print(magic(execPath, args.mode[1]))
+    }
   }
 }