import z from "zod"
import { setTimeout as sleep } from "node:timers/promises"
import { fn } from "@/util/fn"
import { Database, asc, eq, inArray } from "@/storage"
import { Project } from "@/project"
import { BusEvent } from "@/bus/bus-event"
import { GlobalBus } from "@/bus/global"
import { Auth } from "@/auth"
import { SyncEvent } from "@/sync"
import { EventSequenceTable, EventTable } from "@/sync/event.sql"
import { Flag } from "@/flag/flag"
import { Log } from "@/util"
import { Filesystem } from "@/util"
import { ProjectID } from "@/project/schema"
import { Slug } from "@woozlit/shared/util/slug"
import { WorkspaceTable } from "./workspace.sql"
import { getAdaptor } from "./adaptors"
import { WorkspaceInfo } from "./types"
import { WorkspaceID } from "./schema"
import { parseSSE } from "./sse"
import { Session } from "@/session"
import { SessionTable } from "@/session/session.sql"
import { SessionID } from "@/session/schema"
import { errorData } from "@/util/error"
import { AppRuntime } from "@/effect/app-runtime"
import { waitEvent } from "./util"
import { WorkspaceContext } from "./workspace-context"

export const Info = WorkspaceInfo.meta({
  ref: "Workspace",
})
export type Info = z.infer<typeof Info>

export const ConnectionStatus = z.object({
  workspaceID: WorkspaceID.zod,
  status: z.enum(["connected", "connecting", "disconnected", "error"]),
})
export type ConnectionStatus = z.infer<typeof ConnectionStatus>

const Restore = z.object({
  workspaceID: WorkspaceID.zod,
  sessionID: SessionID.zod,
  total: z.number().int().min(0),
  step: z.number().int().min(0),
})

export const Event = {
  Ready: BusEvent.define(
    "workspace.ready",
    z.object({
      name: z.string(),
    }),
  ),
  Failed: BusEvent.define(
    "workspace.failed",
    z.object({
      message: z.string(),
    }),
  ),
  Restore: BusEvent.define("workspace.restore", Restore),
  Status: BusEvent.define("workspace.status", ConnectionStatus),
}

function fromRow(row: typeof WorkspaceTable.$inferSelect): Info {
  return {
    id: row.id,
    type: row.type,
    branch: row.branch,
    name: row.name,
    directory: row.directory,
    extra: row.extra,
    projectID: row.project_id,
  }
}

const CreateInput = z.object({
  id: WorkspaceID.zod.optional(),
  type: Info.shape.type,
  branch: Info.shape.branch,
  projectID: ProjectID.zod,
  extra: Info.shape.extra,
})

export const create = fn(CreateInput, async (input) => {
  const id = WorkspaceID.ascending(input.id)
  const adaptor = await getAdaptor(input.projectID, input.type)

  const config = await adaptor.configure({ ...input, id, name: Slug.create(), directory: null })

  const info: Info = {
    id,
    type: config.type,
    branch: config.branch ?? null,
    name: config.name ?? null,
    directory: config.directory ?? null,
    extra: config.extra ?? null,
    projectID: input.projectID,
  }

  Database.use((db) => {
    db.insert(WorkspaceTable)
      .values({
        id: info.id,
        type: info.type,
        branch: info.branch,
        name: info.name,
        directory: info.directory,
        extra: info.extra,
        project_id: info.projectID,
      })
      .run()
  })

  const env = {
    WOOZLIT_CODE_AUTH_CONTENT: JSON.stringify(await AppRuntime.runPromise(Auth.Service.use((auth) => auth.all()))),
    WOOZLIT_CODE_WORKSPACE_ID: config.id,
    WOOZLIT_CODE_EXPERIMENTAL_WORKSPACES: "true",
    OTEL_EXPORTER_OTLP_HEADERS: process.env.OTEL_EXPORTER_OTLP_HEADERS,
    OTEL_EXPORTER_OTLP_ENDPOINT: process.env.OTEL_EXPORTER_OTLP_ENDPOINT,
    OTEL_RESOURCE_ATTRIBUTES: process.env.OTEL_RESOURCE_ATTRIBUTES,
  }
  await adaptor.create(config, env)

  startSync(info)

  await waitEvent({
    timeout: TIMEOUT,
    fn(event) {
      if (event.workspace === info.id && event.payload.type === Event.Status.type) {
        const { status } = event.payload.properties
        return status === "error" || status === "connected"
      }
      return false
    },
  })

  return info
})

const SessionRestoreInput = z.object({
  workspaceID: WorkspaceID.zod,
  sessionID: SessionID.zod,
})

export const sessionRestore = fn(SessionRestoreInput, async (input) => {
  log.info("session restore requested", {
    workspaceID: input.workspaceID,
    sessionID: input.sessionID,
  })
  try {
    const space = await get(input.workspaceID)
    if (!space) throw new Error(`Workspace not found: ${input.workspaceID}`)

    const adaptor = await getAdaptor(space.projectID, space.type)
    const target = await adaptor.target(space)

    // Need to switch the workspace of the session
    SyncEvent.run(Session.Event.Updated, {
      sessionID: input.sessionID,
      info: {
        workspaceID: input.workspaceID,
      },
    })

    const rows = Database.use((db) =>
      db
        .select({
          id: EventTable.id,
          aggregateID: EventTable.aggregate_id,
          seq: EventTable.seq,
          type: EventTable.type,
          data: EventTable.data,
        })
        .from(EventTable)
        .where(eq(EventTable.aggregate_id, input.sessionID))
        .orderBy(asc(EventTable.seq))
        .all(),
    )
    if (rows.length === 0) throw new Error(`No events found for session: ${input.sessionID}`)

    const all = rows

    const size = 10
    const sets = Array.from({ length: Math.ceil(all.length / size) }, (_, i) => all.slice(i * size, (i + 1) * size))
    const total = sets.length
    log.info("session restore prepared", {
      workspaceID: input.workspaceID,
      sessionID: input.sessionID,
      workspaceType: space.type,
      directory: space.directory,
      target: target.type === "remote" ? String(route(target.url, "/sync/replay")) : target.directory,
      events: all.length,
      batches: total,
      first: all[0]?.seq,
      last: all.at(-1)?.seq,
    })
    GlobalBus.emit("event", {
      directory: "global",
      workspace: input.workspaceID,
      payload: {
        type: Event.Restore.type,
        properties: {
          workspaceID: input.workspaceID,
          sessionID: input.sessionID,
          total,
          step: 0,
        },
      },
    })
    for (const [i, events] of sets.entries()) {
      log.info("session restore batch starting", {
        workspaceID: input.workspaceID,
        sessionID: input.sessionID,
        step: i + 1,
        total,
        events: events.length,
        first: events[0]?.seq,
        last: events.at(-1)?.seq,
        target: target.type === "remote" ? String(route(target.url, "/sync/replay")) : target.directory,
      })
      if (target.type === "local") {
        SyncEvent.replayAll(events)
        log.info("session restore batch replayed locally", {
          workspaceID: input.workspaceID,
          sessionID: input.sessionID,
          step: i + 1,
          total,
          events: events.length,
        })
      } else {
        const url = route(target.url, "/sync/replay")
        const headers = new Headers(target.headers)
        headers.set("content-type", "application/json")
        const res = await fetch(url, {
          method: "POST",
          headers,
          body: JSON.stringify({
            directory: space.directory ?? "",
            events,
          }),
        })
        if (!res.ok) {
          const body = await res.text()
          log.error("session restore batch failed", {
            workspaceID: input.workspaceID,
            sessionID: input.sessionID,
            step: i + 1,
            total,
            status: res.status,
            body,
          })
          throw new Error(
            `Failed to replay session ${input.sessionID} into workspace ${input.workspaceID}: HTTP ${res.status} ${body}`,
          )
        }
        log.info("session restore batch posted", {
          workspaceID: input.workspaceID,
          sessionID: input.sessionID,
          step: i + 1,
          total,
          status: res.status,
        })
      }
      GlobalBus.emit("event", {
        directory: "global",
        workspace: input.workspaceID,
        payload: {
          type: Event.Restore.type,
          properties: {
            workspaceID: input.workspaceID,
            sessionID: input.sessionID,
            total,
            step: i + 1,
          },
        },
      })
    }

    log.info("session restore complete", {
      workspaceID: input.workspaceID,
      sessionID: input.sessionID,
      batches: total,
    })

    return {
      total,
    }
  } catch (err) {
    log.error("session restore failed", {
      workspaceID: input.workspaceID,
      sessionID: input.sessionID,
      error: errorData(err),
    })
    throw err
  }
})

export function list(project: Project.Info) {
  const rows = Database.use((db) =>
    db.select().from(WorkspaceTable).where(eq(WorkspaceTable.project_id, project.id)).all(),
  )
  const spaces = rows.map(fromRow).sort((a, b) => a.id.localeCompare(b.id))
  return spaces
}

export const get = fn(WorkspaceID.zod, async (id) => {
  const row = Database.use((db) => db.select().from(WorkspaceTable).where(eq(WorkspaceTable.id, id)).get())
  if (!row) return
  return fromRow(row)
})

export const remove = fn(WorkspaceID.zod, async (id) => {
  const sessions = Database.use((db) =>
    db.select({ id: SessionTable.id }).from(SessionTable).where(eq(SessionTable.workspace_id, id)).all(),
  )
  for (const session of sessions) {
    await AppRuntime.runPromise(Session.Service.use((svc) => svc.remove(session.id)))
  }

  const row = Database.use((db) => db.select().from(WorkspaceTable).where(eq(WorkspaceTable.id, id)).get())

  if (row) {
    stopSync(id)

    const info = fromRow(row)
    try {
      const adaptor = await getAdaptor(info.projectID, row.type)
      await adaptor.remove(info)
    } catch {
      log.error("adaptor not available when removing workspace", { type: row.type })
    }
    Database.use((db) => db.delete(WorkspaceTable).where(eq(WorkspaceTable.id, id)).run())
    return info
  }
})

const connections = new Map<WorkspaceID, ConnectionStatus>()
const aborts = new Map<WorkspaceID, AbortController>()
const TIMEOUT = 5000

function setStatus(id: WorkspaceID, status: ConnectionStatus["status"]) {
  const prev = connections.get(id)
  if (prev?.status === status) return
  const next = { workspaceID: id, status }
  connections.set(id, next)

  if (status === "error") {
    aborts.delete(id)
  }

  GlobalBus.emit("event", {
    directory: "global",
    workspace: id,
    payload: {
      type: Event.Status.type,
      properties: next,
    },
  })
}

export function status(): ConnectionStatus[] {
  return [...connections.values()]
}

function synced(state: Record<string, number>) {
  const ids = Object.keys(state)
  if (ids.length === 0) return true

  const done = Object.fromEntries(
    Database.use((db) =>
      db
        .select({
          id: EventSequenceTable.aggregate_id,
          seq: EventSequenceTable.seq,
        })
        .from(EventSequenceTable)
        .where(inArray(EventSequenceTable.aggregate_id, ids))
        .all(),
    ).map((row) => [row.id, row.seq]),
  ) as Record<string, number>

  return ids.every((id) => {
    return (done[id] ?? -1) >= state[id]
  })
}

export async function isSyncing(workspaceID: WorkspaceID) {
  return aborts.has(workspaceID)
}

export async function waitForSync(workspaceID: WorkspaceID, state: Record<string, number>, signal?: AbortSignal) {
  if (synced(state)) return

  try {
    await waitEvent({
      timeout: TIMEOUT,
      signal,
      fn(event) {
        if (event.workspace !== workspaceID && event.payload.type !== "sync") {
          return false
        }
        return synced(state)
      },
    })
  } catch {
    if (signal?.aborted) throw signal.reason ?? new Error("Request aborted")
    throw new Error(`Timed out waiting for sync fence: ${JSON.stringify(state)}`)
  }
}

const log = Log.create({ service: "workspace-sync" })

function route(url: string | URL, path: string) {
  const next = new URL(url)
  next.pathname = `${next.pathname.replace(/\/$/, "")}${path}`
  next.search = ""
  next.hash = ""
  return next
}

async function connectSSE(url: URL | string, headers: HeadersInit | undefined, signal: AbortSignal) {
  const res = await fetch(route(url, "/global/event"), {
    method: "GET",
    headers,
    signal,
  })

  if (!res.ok) throw new Error(`Workspace sync HTTP failure: ${res.status}`)
  if (!res.body) throw new Error("No response body from global sync")

  return res.body
}

async function syncHistory(space: Info, url: URL | string, headers: HeadersInit | undefined, signal: AbortSignal) {
  const sessionIDs = Database.use((db) =>
    db
      .select({ id: SessionTable.id })
      .from(SessionTable)
      .where(eq(SessionTable.workspace_id, space.id))
      .all()
      .map((row) => row.id),
  )
  const state = sessionIDs.length
    ? Object.fromEntries(
        Database.use((db) =>
          db.select().from(EventSequenceTable).where(inArray(EventSequenceTable.aggregate_id, sessionIDs)).all(),
        ).map((row) => [row.aggregate_id, row.seq]),
      )
    : {}

  log.info("syncing workspace history", {
    workspaceID: space.id,
    sessions: sessionIDs.length,
    known: Object.keys(state).length,
  })

  const requestHeaders = new Headers(headers)
  requestHeaders.set("content-type", "application/json")

  const res = await fetch(route(url, "/sync/history"), {
    method: "POST",
    headers: requestHeaders,
    body: JSON.stringify(state),
    signal,
  })

  if (!res.ok) {
    const body = await res.text()
    throw new Error(`Workspace history HTTP failure: ${res.status} ${body}`)
  }

  const events = await res.json()

  return WorkspaceContext.provide({
    workspaceID: space.id,
    fn: () => {
      for (const event of events) {
        SyncEvent.replay(
          {
            id: event.id,
            aggregateID: event.aggregate_id,
            seq: event.seq,
            type: event.type,
            data: event.data,
          },
          { publish: true },
        )
      }
    },
  })

  log.info("workspace history synced", {
    workspaceID: space.id,
    events: events.length,
  })
}

async function syncWorkspaceLoop(space: Info, signal: AbortSignal) {
  const adaptor = await getAdaptor(space.projectID, space.type)
  const target = await adaptor.target(space)

  if (target.type === "local") return null

  let attempt = 0

  while (!signal.aborted) {
    log.info("connecting to global sync", { workspace: space.name })
    setStatus(space.id, "connecting")

    let stream
    try {
      stream = await connectSSE(target.url, target.headers, signal)
      await syncHistory(space, target.url, target.headers, signal)
    } catch (err) {
      stream = null
      setStatus(space.id, "error")
      log.info("failed to connect to global sync", {
        workspace: space.name,
        err,
      })
    }

    if (stream) {
      attempt = 0

      log.info("global sync connected", { workspace: space.name })
      setStatus(space.id, "connected")

      await parseSSE(stream, signal, (evt: any) => {
        try {
          if (!("payload" in evt)) return
          if (evt.payload.type === "server.heartbeat") return

          if (evt.payload.type === "sync") {
            SyncEvent.replay(evt.payload.syncEvent as SyncEvent.SerializedEvent)
          }

          GlobalBus.emit("event", {
            directory: evt.directory,
            project: evt.project,
            workspace: space.id,
            payload: evt.payload,
          })
        } catch (err) {
          log.info("failed to replay global event", {
            workspaceID: space.id,
            error: err,
          })
        }
      })

      log.info("disconnected from global sync: " + space.id)
      setStatus(space.id, "disconnected")
    }

    // Back off reconnect attempts up to 2 minutes while the workspace
    // stays unavailable.
    await sleep(Math.min(120_000, 1_000 * 2 ** attempt))
    attempt += 1
  }
}

async function startSync(space: Info) {
  if (!Flag.WOOZLIT_CODE_EXPERIMENTAL_WORKSPACES) return

  const adaptor = await getAdaptor(space.projectID, space.type)
  const target = await adaptor.target(space)

  if (target.type === "local") {
    void Filesystem.exists(target.directory).then((exists) => {
      setStatus(space.id, exists ? "connected" : "error")
    })
    return
  }

  if (aborts.has(space.id)) return true

  setStatus(space.id, "disconnected")

  const abort = new AbortController()
  aborts.set(space.id, abort)

  void syncWorkspaceLoop(space, abort.signal).catch((error) => {
    aborts.delete(space.id)

    setStatus(space.id, "error")
    log.warn("workspace listener failed", {
      workspaceID: space.id,
      error,
    })
  })
}

function stopSync(id: WorkspaceID) {
  aborts.get(id)?.abort()
  aborts.delete(id)
  connections.delete(id)
}

export function startWorkspaceSyncing(projectID: ProjectID) {
  const spaces = Database.use((db) =>
    db
      .select({ workspace: WorkspaceTable })
      .from(WorkspaceTable)
      .innerJoin(SessionTable, eq(SessionTable.workspace_id, WorkspaceTable.id))
      .where(eq(WorkspaceTable.project_id, projectID))
      .all(),
  )

  for (const row of new Map(spaces.map((row) => [row.workspace.id, row.workspace])).values()) {
    void startSync(fromRow(row))
  }
}

export * as Workspace from "./workspace"
