import z from "zod"
import { NamedError } from "@opencode-ai/core/util/error"
import { Global } from "@opencode-ai/core/global"
import { Instance } from "../project/instance"
import { InstanceBootstrap } from "../project/bootstrap"
import { Project } from "../project"
import { Database, eq } from "../storage"
import { ProjectTable } from "../project/project.sql"
import type { ProjectID } from "../project/schema"
import { Log } from "../util"
import { Slug } from "@opencode-ai/core/util/slug"
import { errorMessage } from "../util/error"
import { BusEvent } from "@/bus/bus-event"
import { GlobalBus } from "@/bus/global"
import { Git } from "@/git"
import { Effect, Layer, Path, Schema, Scope, Context, Stream } from "effect"
import { ChildProcess, ChildProcessSpawner } from "effect/unstable/process"
import { NodePath } from "@effect/platform-node"
import { AppFileSystem } from "@opencode-ai/core/filesystem"
import { BootstrapRuntime } from "@/effect/bootstrap-runtime"
import { CrossSpawnSpawner } from "@opencode-ai/core/cross-spawn-spawner"
import { InstanceState } from "@/effect"
import { zod as effectZod } from "@/util/effect-zod"
import { withStatics } from "@/util/schema"

const log = Log.create({ service: "worktree" })

export const Event = {
  Ready: BusEvent.define(
    "worktree.ready",
    Schema.Struct({
      name: Schema.String,
      branch: Schema.String,
    }),
  ),
  Failed: BusEvent.define(
    "worktree.failed",
    Schema.Struct({
      message: Schema.String,
    }),
  ),
}

export const Info = Schema.Struct({
  name: Schema.String,
  branch: Schema.String,
  directory: Schema.String,
})
  .annotate({ identifier: "Worktree" })
  .pipe(withStatics((s) => ({ zod: effectZod(s) })))
export type Info = Schema.Schema.Type<typeof Info>

export const CreateInput = Schema.Struct({
  name: Schema.optional(Schema.String),
  startCommand: Schema.optional(
    Schema.String.annotate({ description: "Additional startup script to run after the project's start command" }),
  ),
})
  .annotate({ identifier: "WorktreeCreateInput" })
  .pipe(withStatics((s) => ({ zod: effectZod(s) })))
export type CreateInput = Schema.Schema.Type<typeof CreateInput>

export const RemoveInput = Schema.Struct({
  directory: Schema.String,
})
  .annotate({ identifier: "WorktreeRemoveInput" })
  .pipe(withStatics((s) => ({ zod: effectZod(s) })))
export type RemoveInput = Schema.Schema.Type<typeof RemoveInput>

export const ResetInput = Schema.Struct({
  directory: Schema.String,
})
  .annotate({ identifier: "WorktreeResetInput" })
  .pipe(withStatics((s) => ({ zod: effectZod(s) })))
export type ResetInput = Schema.Schema.Type<typeof ResetInput>

export const NotGitError = NamedError.create(
  "WorktreeNotGitError",
  z.object({
    message: z.string(),
  }),
)

export const NameGenerationFailedError = NamedError.create(
  "WorktreeNameGenerationFailedError",
  z.object({
    message: z.string(),
  }),
)

export const CreateFailedError = NamedError.create(
  "WorktreeCreateFailedError",
  z.object({
    message: z.string(),
  }),
)

export const StartCommandFailedError = NamedError.create(
  "WorktreeStartCommandFailedError",
  z.object({
    message: z.string(),
  }),
)

export const RemoveFailedError = NamedError.create(
  "WorktreeRemoveFailedError",
  z.object({
    message: z.string(),
  }),
)

export const ResetFailedError = NamedError.create(
  "WorktreeResetFailedError",
  z.object({
    message: z.string(),
  }),
)

function slugify(input: string) {
  return input
    .trim()
    .toLowerCase()
    .replace(/[^a-z0-9]+/g, "-")
    .replace(/^-+/, "")
    .replace(/-+$/, "")
}

function failedRemoves(...chunks: string[]) {
  return chunks.filter(Boolean).flatMap((chunk) =>
    chunk
      .split("\n")
      .map((line) => line.trim())
      .flatMap((line) => {
        const match = line.match(/^warning:\s+failed to remove\s+(.+):\s+/i)
        if (!match) return []
        const value = match[1]?.trim().replace(/^['"]|['"]$/g, "")
        if (!value) return []
        return [value]
      }),
  )
}

// ---------------------------------------------------------------------------
// Effect service
// ---------------------------------------------------------------------------

export interface Interface {
  readonly makeWorktreeInfo: (name?: string) => Effect.Effect<Info>
  readonly createFromInfo: (info: Info, startCommand?: string) => Effect.Effect<void>
  readonly create: (input?: CreateInput) => Effect.Effect<Info>
  readonly remove: (input: RemoveInput) => Effect.Effect<boolean>
  readonly reset: (input: ResetInput) => Effect.Effect<boolean>
}

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

type GitResult = { code: number; text: string; stderr: string }

export const layer: Layer.Layer<
  Service,
  never,
  AppFileSystem.Service | Path.Path | ChildProcessSpawner.ChildProcessSpawner | Git.Service | Project.Service
> = Layer.effect(
  Service,
  Effect.gen(function* () {
    const scope = yield* Scope.Scope
    const fs = yield* AppFileSystem.Service
    const pathSvc = yield* Path.Path
    const spawner = yield* ChildProcessSpawner.ChildProcessSpawner
    const gitSvc = yield* Git.Service
    const project = yield* Project.Service

    const git = Effect.fnUntraced(
      function* (args: string[], opts?: { cwd?: string }) {
        const handle = yield* spawner.spawn(
          ChildProcess.make("git", args, { cwd: opts?.cwd, extendEnv: true, stdin: "ignore" }),
        )
        const [text, stderr] = yield* Effect.all(
          [Stream.mkString(Stream.decodeText(handle.stdout)), Stream.mkString(Stream.decodeText(handle.stderr))],
          { concurrency: 2 },
        )
        const code = yield* handle.exitCode
        return { code, text, stderr } satisfies GitResult
      },
      Effect.scoped,
      Effect.catch((e) =>
        Effect.succeed({ code: 1, text: "", stderr: e instanceof Error ? e.message : String(e) } satisfies GitResult),
      ),
    )

    const MAX_NAME_ATTEMPTS = 26
    const candidate = Effect.fn("Worktree.candidate")(function* (root: string, base?: string) {
      const ctx = yield* InstanceState.context
      for (const attempt of Array.from({ length: MAX_NAME_ATTEMPTS }, (_, i) => i)) {
        const name = base ? (attempt === 0 ? base : `${base}-${Slug.create()}`) : Slug.create()
        const branch = `opencode/${name}`
        const directory = pathSvc.join(root, name)

        if (yield* fs.exists(directory).pipe(Effect.orDie)) continue

        const ref = `refs/heads/${branch}`
        const branchCheck = yield* git(["show-ref", "--verify", "--quiet", ref], { cwd: ctx.worktree })
        if (branchCheck.code === 0) continue

        return { name, branch, directory }
      }
      throw new NameGenerationFailedError({ message: "Failed to generate a unique worktree name" })
    })

    const makeWorktreeInfo = Effect.fn("Worktree.makeWorktreeInfo")(function* (name?: string) {
      const ctx = yield* InstanceState.context
      if (ctx.project.vcs !== "git") {
        throw new NotGitError({ message: "Worktrees are only supported for git projects" })
      }

      const root = pathSvc.join(Global.Path.data, "worktree", ctx.project.id)
      yield* fs.makeDirectory(root, { recursive: true }).pipe(Effect.orDie)

      const base = name ? slugify(name) : ""
      return yield* candidate(root, base || undefined)
    })

    const setup = Effect.fnUntraced(function* (info: Info) {
      const ctx = yield* InstanceState.context
      const created = yield* git(["worktree", "add", "--no-checkout", "-b", info.branch, info.directory], {
        cwd: ctx.worktree,
      })
      if (created.code !== 0) {
        throw new CreateFailedError({ message: created.stderr || created.text || "Failed to create git worktree" })
      }

      yield* project.addSandbox(ctx.project.id, info.directory).pipe(Effect.catch(() => Effect.void))
    })

    const boot = Effect.fnUntraced(function* (info: Info, startCommand?: string) {
      const ctx = yield* InstanceState.context
      const workspaceID = yield* InstanceState.workspaceID
      const projectID = ctx.project.id
      const extra = startCommand?.trim()

      const populated = yield* git(["reset", "--hard"], { cwd: info.directory })
      if (populated.code !== 0) {
        const message = populated.stderr || populated.text || "Failed to populate worktree"
        log.error("worktree checkout failed", { directory: info.directory, message })
        GlobalBus.emit("event", {
          directory: info.directory,
          project: ctx.project.id,
          workspace: workspaceID,
          payload: { type: Event.Failed.type, properties: { message } },
        })
        return
      }

      const booted = yield* Effect.promise(() =>
        Instance.provide({
          directory: info.directory,
          init: () => BootstrapRuntime.runPromise(InstanceBootstrap),
          fn: () => undefined,
        })
          .then(() => true)
          .catch((error) => {
            const message = errorMessage(error)
            log.error("worktree bootstrap failed", { directory: info.directory, message })
            GlobalBus.emit("event", {
              directory: info.directory,
              project: ctx.project.id,
              workspace: workspaceID,
              payload: { type: Event.Failed.type, properties: { message } },
            })
            return false
          }),
      )
      if (!booted) return

      GlobalBus.emit("event", {
        directory: info.directory,
        project: ctx.project.id,
        workspace: workspaceID,
        payload: {
          type: Event.Ready.type,
          properties: { name: info.name, branch: info.branch },
        },
      })

      yield* runStartScripts(info.directory, { projectID, extra })
    })

    const createFromInfo = Effect.fn("Worktree.createFromInfo")(function* (info: Info, startCommand?: string) {
      yield* setup(info)
      yield* boot(info, startCommand)
    })

    const create = Effect.fn("Worktree.create")(function* (input?: CreateInput) {
      const info = yield* makeWorktreeInfo(input?.name)
      yield* setup(info)
      yield* boot(info, input?.startCommand).pipe(
        Effect.catchCause((cause) => Effect.sync(() => log.error("worktree bootstrap failed", { cause }))),
        Effect.forkIn(scope),
      )
      return info
    })

    const canonical = Effect.fnUntraced(function* (input: string) {
      const abs = pathSvc.resolve(input)
      const real = yield* fs.realPath(abs).pipe(Effect.catch(() => Effect.succeed(abs)))
      const normalized = pathSvc.normalize(real)
      return process.platform === "win32" ? normalized.toLowerCase() : normalized
    })

    function parseWorktreeList(text: string) {
      return text
        .split("\n")
        .map((line) => line.trim())
        .reduce<{ path?: string; branch?: string }[]>((acc, line) => {
          if (!line) return acc
          if (line.startsWith("worktree ")) {
            acc.push({ path: line.slice("worktree ".length).trim() })
            return acc
          }
          const current = acc[acc.length - 1]
          if (!current) return acc
          if (line.startsWith("branch ")) {
            current.branch = line.slice("branch ".length).trim()
          }
          return acc
        }, [])
    }

    const locateWorktree = Effect.fnUntraced(function* (
      entries: { path?: string; branch?: string }[],
      directory: string,
    ) {
      for (const item of entries) {
        if (!item.path) continue
        const key = yield* canonical(item.path)
        if (key === directory) return item
      }
      return undefined
    })

    function stopFsmonitor(target: string) {
      return fs.exists(target).pipe(
        Effect.orDie,
        Effect.flatMap((exists) => (exists ? git(["fsmonitor--daemon", "stop"], { cwd: target }) : Effect.void)),
      )
    }

    function cleanDirectory(target: string) {
      return Effect.promise(() =>
        import("fs/promises")
          .then((fsp) => fsp.rm(target, { recursive: true, force: true, maxRetries: 5, retryDelay: 100 }))
          .catch((error) => {
            const message = errorMessage(error)
            throw new RemoveFailedError({ message: message || "Failed to remove git worktree directory" })
          }),
      )
    }

    const remove = Effect.fn("Worktree.remove")(function* (input: RemoveInput) {
      const ctx = yield* InstanceState.context
      if (ctx.project.vcs !== "git") {
        throw new NotGitError({ message: "Worktrees are only supported for git projects" })
      }

      const directory = yield* canonical(input.directory)

      const list = yield* git(["worktree", "list", "--porcelain"], { cwd: ctx.worktree })
      if (list.code !== 0) {
        throw new RemoveFailedError({ message: list.stderr || list.text || "Failed to read git worktrees" })
      }

      const entries = parseWorktreeList(list.text)
      const entry = yield* locateWorktree(entries, directory)

      if (!entry?.path) {
        const directoryExists = yield* fs.exists(directory).pipe(Effect.orDie)
        if (directoryExists) {
          yield* stopFsmonitor(directory)
          yield* cleanDirectory(directory)
        }
        return true
      }

      yield* stopFsmonitor(entry.path)
      const removed = yield* git(["worktree", "remove", "--force", entry.path], { cwd: ctx.worktree })
      if (removed.code !== 0) {
        const next = yield* git(["worktree", "list", "--porcelain"], { cwd: ctx.worktree })
        if (next.code !== 0) {
          throw new RemoveFailedError({
            message: removed.stderr || removed.text || next.stderr || next.text || "Failed to remove git worktree",
          })
        }

        const stale = yield* locateWorktree(parseWorktreeList(next.text), directory)
        if (stale?.path) {
          throw new RemoveFailedError({ message: removed.stderr || removed.text || "Failed to remove git worktree" })
        }
      }

      yield* cleanDirectory(entry.path)

      const branch = entry.branch?.replace(/^refs\/heads\//, "")
      if (branch) {
        const deleted = yield* git(["branch", "-D", branch], { cwd: ctx.worktree })
        if (deleted.code !== 0) {
          throw new RemoveFailedError({
            message: deleted.stderr || deleted.text || "Failed to delete worktree branch",
          })
        }
      }

      return true
    })

    const gitExpect = Effect.fnUntraced(function* (
      args: string[],
      opts: { cwd: string },
      error: (r: GitResult) => Error,
    ) {
      const result = yield* git(args, opts)
      if (result.code !== 0) throw error(result)
      return result
    })

    const runStartCommand = Effect.fnUntraced(
      function* (directory: string, cmd: string) {
        const [shell, args] = process.platform === "win32" ? ["cmd", ["/c", cmd]] : ["bash", ["-lc", cmd]]
        const handle = yield* spawner.spawn(
          ChildProcess.make(shell, args, { cwd: directory, extendEnv: true, stdin: "ignore" }),
        )
        // Drain stdout, capture stderr for error reporting
        const [, stderr] = yield* Effect.all(
          [Stream.runDrain(handle.stdout), Stream.mkString(Stream.decodeText(handle.stderr))],
          { concurrency: 2 },
        ).pipe(Effect.orDie)
        const code = yield* handle.exitCode
        return { code, stderr }
      },
      Effect.scoped,
      Effect.catch(() => Effect.succeed({ code: 1, stderr: "" })),
    )

    const runStartScript = Effect.fnUntraced(function* (directory: string, cmd: string, kind: string) {
      const text = cmd.trim()
      if (!text) return true
      const result = yield* runStartCommand(directory, text)
      if (result.code === 0) return true
      log.error("worktree start command failed", { kind, directory, message: result.stderr })
      return false
    })

    const runStartScripts = Effect.fnUntraced(function* (
      directory: string,
      input: { projectID: ProjectID; extra?: string },
    ) {
      const row = yield* Effect.sync(() =>
        Database.use((db) => db.select().from(ProjectTable).where(eq(ProjectTable.id, input.projectID)).get()),
      )
      const project = row ? Project.fromRow(row) : undefined
      const startup = project?.commands?.start?.trim() ?? ""
      const ok = yield* runStartScript(directory, startup, "project")
      if (!ok) return false
      yield* runStartScript(directory, input.extra ?? "", "worktree")
      return true
    })

    const prune = Effect.fnUntraced(function* (root: string, entries: string[]) {
      const base = yield* canonical(root)
      yield* Effect.forEach(
        entries,
        (entry) =>
          Effect.gen(function* () {
            const target = yield* canonical(pathSvc.resolve(root, entry))
            if (target === base) return
            if (!target.startsWith(`${base}${pathSvc.sep}`)) return
            yield* fs.remove(target, { recursive: true }).pipe(Effect.ignore)
          }),
        { concurrency: "unbounded" },
      )
    })

    const sweep = Effect.fnUntraced(function* (root: string) {
      const first = yield* git(["clean", "-ffdx"], { cwd: root })
      if (first.code === 0) return first

      const entries = failedRemoves(first.stderr, first.text)
      if (!entries.length) return first

      yield* prune(root, entries)
      return yield* git(["clean", "-ffdx"], { cwd: root })
    })

    const reset = Effect.fn("Worktree.reset")(function* (input: ResetInput) {
      const ctx = yield* InstanceState.context
      if (ctx.project.vcs !== "git") {
        throw new NotGitError({ message: "Worktrees are only supported for git projects" })
      }

      const directory = yield* canonical(input.directory)
      const primary = yield* canonical(ctx.worktree)
      if (directory === primary) {
        throw new ResetFailedError({ message: "Cannot reset the primary workspace" })
      }

      const list = yield* git(["worktree", "list", "--porcelain"], { cwd: ctx.worktree })
      if (list.code !== 0) {
        throw new ResetFailedError({ message: list.stderr || list.text || "Failed to read git worktrees" })
      }

      const entry = yield* locateWorktree(parseWorktreeList(list.text), directory)
      if (!entry?.path) {
        throw new ResetFailedError({ message: "Worktree not found" })
      }

      const worktreePath = entry.path

      const base = yield* gitSvc.defaultBranch(ctx.worktree)
      if (!base) {
        throw new ResetFailedError({ message: "Default branch not found" })
      }

      const sep = base.ref.indexOf("/")
      if (base.ref !== base.name && sep > 0) {
        const remote = base.ref.slice(0, sep)
        const branch = base.ref.slice(sep + 1)
        yield* gitExpect(
          ["fetch", remote, branch],
          { cwd: ctx.worktree },
          (r) => new ResetFailedError({ message: r.stderr || r.text || `Failed to fetch ${base.ref}` }),
        )
      }

      yield* gitExpect(
        ["reset", "--hard", base.ref],
        { cwd: worktreePath },
        (r) => new ResetFailedError({ message: r.stderr || r.text || "Failed to reset worktree to target" }),
      )

      const cleanResult = yield* sweep(worktreePath)
      if (cleanResult.code !== 0) {
        throw new ResetFailedError({ message: cleanResult.stderr || cleanResult.text || "Failed to clean worktree" })
      }

      yield* gitExpect(
        ["submodule", "update", "--init", "--recursive", "--force"],
        { cwd: worktreePath },
        (r) => new ResetFailedError({ message: r.stderr || r.text || "Failed to update submodules" }),
      )

      yield* gitExpect(
        ["submodule", "foreach", "--recursive", "git", "reset", "--hard"],
        { cwd: worktreePath },
        (r) => new ResetFailedError({ message: r.stderr || r.text || "Failed to reset submodules" }),
      )

      yield* gitExpect(
        ["submodule", "foreach", "--recursive", "git", "clean", "-fdx"],
        { cwd: worktreePath },
        (r) => new ResetFailedError({ message: r.stderr || r.text || "Failed to clean submodules" }),
      )

      const status = yield* git(["-c", "core.fsmonitor=false", "status", "--porcelain=v1"], { cwd: worktreePath })
      if (status.code !== 0) {
        throw new ResetFailedError({ message: status.stderr || status.text || "Failed to read git status" })
      }

      if (status.text.trim()) {
        throw new ResetFailedError({ message: `Worktree reset left local changes:\n${status.text.trim()}` })
      }

      yield* runStartScripts(worktreePath, { projectID: ctx.project.id }).pipe(
        Effect.catchCause((cause) => Effect.sync(() => log.error("worktree start task failed", { cause }))),
        Effect.forkIn(scope),
      )

      return true
    })

    return Service.of({ makeWorktreeInfo, createFromInfo, create, remove, reset })
  }),
)

export const defaultLayer = layer.pipe(
  Layer.provide(Git.defaultLayer),
  Layer.provide(CrossSpawnSpawner.defaultLayer),
  Layer.provide(Project.defaultLayer),
  Layer.provide(AppFileSystem.defaultLayer),
  Layer.provide(NodePath.layer),
)

export * as Worktree from "."
