diff --git a/.dockerignore b/.dockerignore
new file mode 100644
index 0000000..3ef40a9
--- /dev/null
+++ b/.dockerignore
@@ -0,0 +1,4 @@
+/.git
+/node_modules
+/test-repo
+/.tags
diff --git a/.drone.jsonnet b/.drone.jsonnet
new file mode 100644
index 0000000..e762cf5
--- /dev/null
+++ b/.drone.jsonnet
@@ -0,0 +1,71 @@
+local bun_image = "oven/bun:0.8.1";
+
+
+local install_run_step = {
+    name: "install-run",
+    image: bun_image,
+    commands: [
+        "apt update -y && apt full-upgrade -y && apt install -y --no-install-recommends git",
+        "bun install --production --frozen-lockfile --no-cache",
+        "bun start .",
+    ],
+};
+
+local build_docker_step(publish) = {
+    name: "build-" + (if publish then "publish-" else "") + "docker",
+    image: "plugins/docker",
+
+    settings: {
+        dry_run: !publish,
+        registry: "git.jvalver.de",
+        username: { from_secret: "docker_username" },
+        password: { from_secret: "docker_password" },
+        repo: "git.jvalver.de/thilawyn/drone-better-docker-autotag",
+        dockerfile: "Dockerfile",
+        context: ".",
+        compress: true,
+        platform: "linux/amd64",
+    },
+};
+
+
+[
+    // Build docker images without publishing them for pull requests
+    {
+        kind: "pipeline",
+        type: "docker",
+        name: "build-docker",
+
+        trigger: {
+            ref: {
+                include: ["refs/pull/**"]
+            }
+        },
+
+        steps: [
+            install_run_step,
+            build_docker_step(false),
+        ],
+    },
+
+    // Build docker images and publish them for master and tags
+    {
+        kind: "pipeline",
+        type: "docker",
+        name: "build-publish-docker",
+
+        trigger: {
+            ref: {
+                include: [
+                    "refs/heads/master",
+                    "refs/tags/**",
+                ]
+            }
+        },
+
+        steps: [
+            install_run_step,
+            build_docker_step(true),
+        ],
+    },
+]
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..ab152ae
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,3 @@
+/node_modules
+/test-repo
+/.tags
diff --git a/Dockerfile b/Dockerfile
new file mode 100644
index 0000000..9480aa9
--- /dev/null
+++ b/Dockerfile
@@ -0,0 +1,12 @@
+FROM oven/bun:0.8.1
+
+RUN apt update -y && \
+    apt full-upgrade -y && \
+    apt install -y --no-install-recommends git && \
+    apt autoremove -y --purge && \
+    apt clean
+
+COPY ./ ./
+RUN bun install --production --frozen-lockfile --no-cache && \
+    rm -rf ~/.bun
+ENTRYPOINT ["bun", "start", "/drone/src"]
diff --git a/bun.lockb b/bun.lockb
new file mode 100755
index 0000000..7135984
Binary files /dev/null and b/bun.lockb differ
diff --git a/package.json b/package.json
new file mode 100644
index 0000000..490bfd8
--- /dev/null
+++ b/package.json
@@ -0,0 +1,26 @@
+{
+  "name": "drone-better-docker-autotag",
+  "module": "index.ts",
+  "type": "module",
+  "scripts": {
+    "start": "NODE_ENV=production bun src/index.ts",
+    "start:dev": "NODE_ENV=development bun src/index.ts"
+  },
+  "devDependencies": {
+    "@types/lodash-es": "^4.17.8",
+    "@types/semver": "^7.5.0",
+    "bun-types": "latest",
+    "type-fest": "^4.2.0"
+  },
+  "peerDependencies": {
+    "typescript": "^5.0.0"
+  },
+  "dependencies": {
+    "@effect/schema": "^0.33.2",
+    "effect": "^2.0.0-next.29",
+    "lodash-es": "^4.17.21",
+    "semver": "^7.5.4",
+    "simple-git": "^3.19.1",
+    "trim-newlines": "^5.0.0"
+  }
+}
diff --git a/src/argv.ts b/src/argv.ts
new file mode 100644
index 0000000..0a571c8
--- /dev/null
+++ b/src/argv.ts
@@ -0,0 +1,18 @@
+import * as S from "@effect/schema/Schema"
+import { Opaque } from "type-fest"
+
+
+export type BunPath  = Opaque<string, "BunPath">
+export type MainPath = Opaque<string, "MainPath">
+export type GitPath  = Opaque<string, "RepoPath">
+
+export const ArgvSchema = S.tuple(
+    S.literal<[BunPath]>(Bun.which("bun") as BunPath),
+    S.literal<[MainPath]>(Bun.main as MainPath),
+    S.string as unknown as S.Schema<GitPath, GitPath>,
+)
+
+export type Argv = S.To<typeof ArgvSchema>
+
+export const parseArgv = () =>
+    S.parse(ArgvSchema)(process.argv)
diff --git a/src/env.ts b/src/env.ts
new file mode 100644
index 0000000..4c2947a
--- /dev/null
+++ b/src/env.ts
@@ -0,0 +1,16 @@
+import * as S from "@effect/schema/Schema"
+
+
+export const EnvSchema = S.struct({
+    NODE_ENV: S.union(
+        S.literal("development"),
+        S.literal("production"),
+    ),
+
+    // PLUGIN_CALVER_FORMAT: S.optional(S.string),
+})
+
+export type Env = S.To<typeof EnvSchema>
+
+export const parseEnv = () =>
+    S.parse(EnvSchema)(process.env)
diff --git a/src/git.ts b/src/git.ts
new file mode 100644
index 0000000..d1312b5
--- /dev/null
+++ b/src/git.ts
@@ -0,0 +1,104 @@
+import { Context, Effect, pipe } from "effect"
+import { GitConstructError, GitError, GitPluginError, GitResponseError, SimpleGit } from "simple-git"
+import { trimNewlines } from "trim-newlines"
+import { Opaque } from "type-fest"
+
+
+export const SimpleGitService = Context.Tag<SimpleGit>()
+
+function mapSimpleGitErrors(e: unknown): GitError
+                                       | GitConstructError
+                                       | GitPluginError
+                                       | GitResponseError
+                                       | Error
+{
+    if (e instanceof GitError
+     || e instanceof GitConstructError
+     || e instanceof GitPluginError
+     || e instanceof GitResponseError)
+        return e
+
+    return new Error(`simpleGit failed with a unknown error: ${ e }`)
+}
+
+
+export type GitRefName       = Opaque<string, "GitRefName">
+export type GitRefCommitHash = Opaque<string, "GitRefCommitHash">
+
+export class GitRef {
+    constructor(
+        readonly name: GitRefName,
+        readonly commit: GitRefCommitHash,
+    ) {}
+}
+
+export class GitBranchRef extends GitRef {}
+export class GitTagRef extends GitRef {}
+
+
+export class GitRefNullNameError {}
+
+export const getGitRefName = pipe(
+    SimpleGitService,
+
+    Effect.flatMap(git =>
+        Effect.tryPromise({
+            try: async () =>
+                (await git.status()).current as GitRefName | null,
+
+            catch: mapSimpleGitErrors,
+        })
+    ),
+
+    Effect.flatMap(name =>
+        name
+            ? Effect.succeed(name)
+            : Effect.fail(new GitRefNullNameError)
+    ),
+)
+
+
+export const getGitRefTagName = pipe(
+    SimpleGitService,
+
+    Effect.flatMap(git =>
+        Effect.tryPromise({
+            try: async () =>
+                trimNewlines( await git.raw("describe", "--tags", "--exact-match") ) as GitRefName,
+
+            catch: mapSimpleGitErrors,
+        })
+    ),
+)
+
+
+export const getGitRefCommitHash = pipe(
+    SimpleGitService,
+
+    Effect.flatMap(git =>
+        Effect.tryPromise({
+            try: async () =>
+                trimNewlines( await git.raw("show", "--format=%h", "--no-patch") ) as GitRefCommitHash,
+
+            catch: mapSimpleGitErrors,
+        })
+    ),
+)
+
+
+export const getGitRef = pipe(
+    Effect.all([
+        getGitRefName,
+        getGitRefCommitHash,
+    ]),
+
+    Effect.flatMap(([name, commit]) =>
+        name !== "HEAD" ?
+            Effect.succeed(new GitBranchRef(name, commit) as GitRef)
+        :
+            pipe(
+                getGitRefTagName,
+                Effect.map(name => new GitTagRef(name, commit) as GitRef),
+            )
+    ),
+)
diff --git a/src/index.ts b/src/index.ts
new file mode 100644
index 0000000..00f6ec1
--- /dev/null
+++ b/src/index.ts
@@ -0,0 +1,41 @@
+import { Console, Context, Effect, pipe } from "effect"
+import simpleGit from "simple-git"
+import { parseArgv } from "./argv"
+import { parseEnv } from "./env"
+import { SimpleGitService, getGitRef } from "./git"
+import { DefaultMatcher, SemVerMatcher, generateDockerTagsFromGitRef } from "./matchers"
+import { writeDockerTagsFile } from "./tags"
+
+
+const [ _env, [,, gitPath] ] = await Effect.runPromise(
+    Effect.all([parseEnv(), parseArgv()])
+)
+
+const context = Context.empty().pipe(
+    Context.add(
+        SimpleGitService,
+        SimpleGitService.of(simpleGit(gitPath)),
+    )
+)
+
+const main = pipe(
+    getGitRef,
+
+    Effect.flatMap(ref => generateDockerTagsFromGitRef(ref, [
+        new SemVerMatcher,
+        new DefaultMatcher,
+    ])),
+
+    Effect.tap(tags =>
+        Console.log(`Generated tags: ${ tags.join(", ") }`)
+    ),
+
+    Effect.flatMap(tags => writeDockerTagsFile(gitPath, tags)),
+)
+
+await Effect.runPromise(
+    Effect.provideContext(
+        main,
+        context,
+    )
+)
diff --git a/src/matchers/CalVerMatcher.ts b/src/matchers/CalVerMatcher.ts
new file mode 100644
index 0000000..283a0b7
--- /dev/null
+++ b/src/matchers/CalVerMatcher.ts
@@ -0,0 +1,17 @@
+import { Effect } from "effect"
+import { GitRef } from "../git"
+import { GitRefMatcher } from "./GitRefMatcher"
+
+
+export class   CalVerMatcher
+       extends GitRefMatcher<never, Error> {
+
+    constructor(private format: string) {
+        super()
+    }
+
+    match(_ref: GitRef) {
+        return Effect.fail(new Error("Not implemented"))
+    }
+
+}
diff --git a/src/matchers/DefaultMatcher.ts b/src/matchers/DefaultMatcher.ts
new file mode 100644
index 0000000..38212b5
--- /dev/null
+++ b/src/matchers/DefaultMatcher.ts
@@ -0,0 +1,19 @@
+import { Effect, Option } from "effect"
+import { GitRef } from "../git"
+import { DockerTag } from "../tags"
+import { GitRefMatcher } from "./GitRefMatcher"
+
+
+export class   DefaultMatcher
+       extends GitRefMatcher<never, never> {
+
+    match(ref: GitRef) {
+        return Effect.succeed(
+            Option.some([
+                ref.name,
+                `${ ref.name }-${ ref.commit }`,
+            ] as DockerTag[])
+        )
+    }
+
+}
diff --git a/src/matchers/GitRefMatcher.ts b/src/matchers/GitRefMatcher.ts
new file mode 100644
index 0000000..5034cb9
--- /dev/null
+++ b/src/matchers/GitRefMatcher.ts
@@ -0,0 +1,8 @@
+import { Effect, Option } from "effect"
+import { GitRef } from "../git"
+import { DockerTag } from "../tags"
+
+
+export abstract class GitRefMatcher<R, E> {
+    abstract match(ref: GitRef): Effect.Effect<R, E, Option.Option<DockerTag[]>>
+}
diff --git a/src/matchers/SemVerMatcher.ts b/src/matchers/SemVerMatcher.ts
new file mode 100644
index 0000000..f166042
--- /dev/null
+++ b/src/matchers/SemVerMatcher.ts
@@ -0,0 +1,56 @@
+import { Effect, Option } from "effect"
+import { isEmpty, reverse, tail } from "lodash-es"
+import semver from "semver"
+import { GitRef, GitTagRef } from "../git"
+import { DockerTag } from "../tags"
+import { GitRefMatcher } from "./GitRefMatcher"
+
+
+export class   SemVerMatcher
+       extends GitRefMatcher<never, TypeError | Error> {
+
+    match(ref: GitRef) {
+        return (ref instanceof GitTagRef && semver.valid(ref.name)) ?
+            Effect.try({
+                try: () => {
+                    const prerelease = semver.prerelease(ref.name)
+
+                    return Option.some(
+                        !prerelease ? [
+                            "latest",
+                            ...this.generateTags([
+                                semver.major(ref.name),
+                                semver.minor(ref.name),
+                                semver.patch(ref.name),
+                            ]),
+                        ] :
+                            this.generateTags(prerelease).map(tag =>
+                                `${ semver.coerce(ref.name) }-${ tag }` as DockerTag
+                            )
+                    ) as Option.Option<DockerTag[]>
+                },
+
+                catch: (e): TypeError | Error => {
+                    if (e instanceof TypeError)
+                        return e
+
+                    return new Error(`An unknown error happened while parsing SemVer: ${ e }`)
+                },
+            })
+        :
+            Effect.succeed(Option.none())
+    }
+
+    private generateTags(numbers: readonly (string | number)[]) {
+        const rec = (numbers: readonly (string | number)[]): DockerTag[] =>
+            isEmpty(numbers)
+                ? []
+                : [
+                    ...rec( tail(numbers) ),
+                    reverse(numbers).join(".") as DockerTag,
+                ]
+
+        return rec( reverse(numbers) )
+    }
+
+}
diff --git a/src/matchers/StubMatcher.ts b/src/matchers/StubMatcher.ts
new file mode 100644
index 0000000..0b4b223
--- /dev/null
+++ b/src/matchers/StubMatcher.ts
@@ -0,0 +1,12 @@
+import { Effect, Option } from "effect"
+import { GitRefMatcher } from "./GitRefMatcher"
+
+
+export class   StubMatcher
+       extends GitRefMatcher<never, never> {
+
+    match() {
+        return Effect.succeed(Option.none())
+    }
+
+}
diff --git a/src/matchers/index.ts b/src/matchers/index.ts
new file mode 100644
index 0000000..55dde28
--- /dev/null
+++ b/src/matchers/index.ts
@@ -0,0 +1,31 @@
+import { Effect, Option } from "effect"
+import { isEmpty, tail } from "lodash-es"
+import { GitRef } from "../git"
+import { DockerTag } from "../tags"
+import { GitRefMatcher } from "./GitRefMatcher"
+
+
+export * from "./CalVerMatcher"
+export * from "./DefaultMatcher"
+export * from "./GitRefMatcher"
+export * from "./SemVerMatcher"
+export * from "./StubMatcher"
+
+
+export class NoMatcherFoundError {}
+
+export const generateDockerTagsFromGitRef = <R, E>(
+    ref:       GitRef,
+    matchers:  GitRefMatcher<R, E>[],
+): Effect.Effect<R, E | NoMatcherFoundError, DockerTag[]> =>
+    isEmpty(matchers) ?
+        Effect.fail(new NoMatcherFoundError)
+    :
+        matchers[0].match(ref).pipe(
+            Effect.flatMap(res =>
+                Option.match(res, {
+                    onSome: Effect.succeed,
+                    onNone: () => generateDockerTagsFromGitRef(ref, tail(matchers))
+                })
+            )
+        )
diff --git a/src/tags.ts b/src/tags.ts
new file mode 100644
index 0000000..ca7e864
--- /dev/null
+++ b/src/tags.ts
@@ -0,0 +1,18 @@
+import { Effect } from "effect"
+import path from "node:path"
+import { Opaque } from "type-fest"
+import { GitPath } from "./argv"
+
+
+export type DockerTag = Opaque<string, "Tag">
+
+
+export const writeDockerTagsFile = (gitPath: GitPath, tags: DockerTag[]) =>
+    Effect.tryPromise({
+        try: async () => {
+            await Bun.write( path.join(gitPath, ".tags"), tags.join(",") )
+        },
+
+        catch: e =>
+            new Error(`Could not write file '${ path.join(gitPath, ".tags") }': ${ e }`),
+    })
diff --git a/tsconfig.json b/tsconfig.json
new file mode 100644
index 0000000..29f8aa0
--- /dev/null
+++ b/tsconfig.json
@@ -0,0 +1,21 @@
+{
+  "compilerOptions": {
+    "lib": ["ESNext"],
+    "module": "esnext",
+    "target": "esnext",
+    "moduleResolution": "bundler",
+    "moduleDetection": "force",
+    "allowImportingTsExtensions": true,
+    "strict": true,
+    "downlevelIteration": true,
+    "skipLibCheck": true,
+    "jsx": "preserve",
+    "allowSyntheticDefaultImports": true,
+    "forceConsistentCasingInFileNames": true,
+    "allowJs": true,
+    "noEmit": true,
+    "types": [
+      "bun-types" // add Bun global
+    ]
+  }
+}