export * as Git from "./git"

import path from "path"
import { Context, Effect, Layer } from "effect"
import { ChildProcess } from "effect/unstable/process"
import { AbsolutePath } from "./schema"
import { AppFileSystem } from "./filesystem"
import { AppProcess } from "./process"

export interface Repo {
  /**
   * The root directory of the working tree that contains the input path.
   *
   * For `/home/me/app/src/file.ts` in a normal clone, this is `/home/me/app`.
   * For `/home/me/app-feature/src/file.ts` in a linked worktree, this is
   * `/home/me/app-feature`.
   */
  readonly directory: AbsolutePath
  /**
   * The shared Git storage directory used by this repo and any linked worktrees.
   *
   * For a normal clone at `/home/me/app`, this is usually `/home/me/app/.git`.
   * For a linked worktree at `/home/me/app-feature` whose main checkout is
   * `/home/me/app`, this is usually `/home/me/app/.git`.
   */
  readonly store: AbsolutePath
}

export interface Interface {
  readonly find: (input: AbsolutePath) => Effect.Effect<Repo | undefined>
  readonly remote: (repo: Repo, name?: string) => Effect.Effect<string | undefined>
  readonly roots: (repo: Repo) => Effect.Effect<string[]>
}

export class Service extends Context.Service<Service, Interface>()("@opencode/GitV2") {}

export const layer = Layer.effect(
  Service,
  Effect.gen(function* () {
    const fs = yield* AppFileSystem.Service
    const proc = yield* AppProcess.Service

    const find = Effect.fn("Git.find")(function* (input: AbsolutePath) {
      const dotgit = yield* fs.up({ targets: [".git"], start: input }).pipe(
        Effect.map((matches) => matches[0]),
        Effect.catch(() => Effect.succeed(undefined)),
      )
      if (!dotgit) return undefined

      const cwd = path.dirname(dotgit)
      const git = run(cwd, proc)
      const topLevel = yield* git(["rev-parse", "--show-toplevel"])
      const commonDir = yield* git(["rev-parse", "--git-common-dir"])
      if (commonDir.exitCode !== 0) return undefined

      return {
        directory: AbsolutePath.make(topLevel.exitCode === 0 ? resolvePath(cwd, topLevel.text) : cwd),
        store: AbsolutePath.make(resolvePath(cwd, commonDir.text)),
      } satisfies Repo
    })

    const remote = Effect.fn("Git.remote")(function* (repo: Repo, name = "origin") {
      const result = yield* run(repo.directory, proc)(["remote", "get-url", name])
      if (result.exitCode !== 0) return undefined
      return result.text.trim() || undefined
    })

    const roots = Effect.fn("Git.roots")(function* (repo: Repo) {
      const result = yield* run(repo.directory, proc)(["rev-list", "--max-parents=0", "HEAD"])
      if (result.exitCode !== 0) return []
      return result.text
        .split("\n")
        .map((item) => item.trim())
        .filter(Boolean)
        .toSorted()
    })

    return Service.of({ find, remote, roots })
  }),
)

export const defaultLayer = layer.pipe(
  Layer.provide(AppFileSystem.defaultLayer),
  Layer.provide(AppProcess.defaultLayer),
)

interface Result {
  readonly exitCode: number
  readonly text: string
}

function run(cwd: string, proc: AppProcess.Interface) {
  return (args: string[]) =>
    proc
      .run(
        ChildProcess.make("git", args, {
          cwd,
          extendEnv: true,
          stdin: "ignore",
        }),
      )
      .pipe(
        Effect.map((result) => ({ exitCode: result.exitCode, text: result.stdout.toString("utf8") }) satisfies Result),
        Effect.catch(() => Effect.succeed({ exitCode: 1, text: "" } satisfies Result)),
      )
}

function resolvePath(cwd: string, value: string) {
  const trimmed = value.replace(/[\r\n]+$/, "")
  if (!trimmed) return cwd
  const normalized = AppFileSystem.windowsPath(trimmed)
  if (path.isAbsolute(normalized)) return path.normalize(normalized)
  return path.resolve(cwd, normalized)
}