import type {
  MessageInfo,
  MessagePartRemovedEvent,
  MessagePartUpdatedEvent,
  MessageRemovedEvent,
  MessageUpdateEvent,
} from "../types/message"
import type {
  EventPermissionReplied,
  EventPermissionUpdated,
  EventSessionCompacted,
  EventSessionError,
  EventSessionIdle,
  EventSessionUpdated,
} from "@opencode-ai/sdk"

import { showToastNotification, ToastVariant } from "../lib/notifications"
import { instances, addPermissionToQueue, removePermissionFromQueue, refreshPermissionsForSession } from "./instances"
import { showAlertDialog } from "./alerts"
import {
  sessions,
  setSessions,
  withSession,
} from "./session-state"
import { normalizeMessagePart, updateSessionInfo } from "./session-messages"
import { loadMessages } from "./session-api"
import { setSessionCompactionState } from "./session-compaction"
import {
  applyPartUpdateV2,
  replaceMessageIdV2,
  upsertMessageInfoV2,
  upsertPermissionV2,
  removePermissionV2,
  setSessionRevertV2,
} from "./message-v2/bridge"
import { messageStoreBus } from "./message-v2/bus"
import type { InstanceMessageStore } from "./message-v2/instance-store"

interface TuiToastEvent {
  type: "tui.toast.show"
  properties: {
    title?: string
    message: string
    variant: "info" | "success" | "warning" | "error"
    duration?: number
  }
}

const ALLOWED_TOAST_VARIANTS = new Set<ToastVariant>(["info", "success", "warning", "error"])

type MessageRole = "user" | "assistant"

function resolveMessageRole(info?: MessageInfo | null): MessageRole {
  return info?.role === "user" ? "user" : "assistant"
}

function findPendingMessageId(
  store: InstanceMessageStore,
  sessionId: string,
  role: MessageRole,
): string | undefined {
  const messageIds = store.getSessionMessageIds(sessionId)
  for (let i = messageIds.length - 1; i >= 0; i -= 1) {
    const record = store.getMessage(messageIds[i])
    if (!record) continue
    if (record.sessionId !== sessionId) continue
    if (record.role !== role) continue
    if (record.status === "sending") {
      return record.id
    }
  }
  return undefined
}

function handleMessageUpdate(instanceId: string, event: MessageUpdateEvent | MessagePartUpdatedEvent): void {
  const instanceSessions = sessions().get(instanceId)
  if (!instanceSessions) return

  if (event.type === "message.part.updated") {
    const rawPart = event.properties?.part
    if (!rawPart) return

    const part = normalizeMessagePart(rawPart)
    const sessionId = typeof part.sessionID === "string" ? part.sessionID : undefined
    const messageId = typeof part.messageID === "string" ? part.messageID : undefined
    if (!sessionId || !messageId) return

    const session = instanceSessions.get(sessionId)
    if (!session) return

    const store = messageStoreBus.getOrCreate(instanceId)
    const messageInfo = event.properties?.message as MessageInfo | undefined
    const role: MessageRole = resolveMessageRole(messageInfo)
    const createdAt = typeof messageInfo?.time?.created === "number" ? messageInfo.time.created : Date.now()

    let record = store.getMessage(messageId)
    if (!record) {
      const pendingId = findPendingMessageId(store, sessionId, role)
      if (pendingId && pendingId !== messageId) {
        replaceMessageIdV2(instanceId, pendingId, messageId)
        record = store.getMessage(messageId)
      }
    }

    if (!record) {
      store.upsertMessage({
        id: messageId,
        sessionId,
        role,
        status: "streaming",
        createdAt,
        updatedAt: createdAt,
        isEphemeral: true,
      })
    }

    if (messageInfo) {
      upsertMessageInfoV2(instanceId, messageInfo, { status: "streaming" })
    }

    applyPartUpdateV2(instanceId, part)

    withSession(instanceId, sessionId, () => {
      /* trigger reactivity for legacy consumers */
    })

    updateSessionInfo(instanceId, sessionId)
    refreshPermissionsForSession(instanceId, sessionId)
  } else if (event.type === "message.updated") {
    const info = event.properties?.info
    if (!info) return

    const sessionId = typeof info.sessionID === "string" ? info.sessionID : undefined
    const messageId = typeof info.id === "string" ? info.id : undefined
    if (!sessionId || !messageId) return

    const session = instanceSessions.get(sessionId)
    if (!session) return

    const store = messageStoreBus.getOrCreate(instanceId)
    const role: MessageRole = info.role === "user" ? "user" : "assistant"

    let record = store.getMessage(messageId)
    if (!record) {
      const pendingId = findPendingMessageId(store, sessionId, role)
      if (pendingId && pendingId !== messageId) {
        replaceMessageIdV2(instanceId, pendingId, messageId)
        record = store.getMessage(messageId)
      }
    }

    if (!record) {
      const createdAt = info.time?.created ?? Date.now()
      const completedAt = (info.time as { completed?: number } | undefined)?.completed
      store.upsertMessage({
        id: messageId,
        sessionId,
        role,
        status: "complete",
        createdAt,
        updatedAt: completedAt ?? createdAt,
      })
    }

    upsertMessageInfoV2(instanceId, info, { status: "complete", bumpRevision: true })

    withSession(instanceId, sessionId, () => {
      /* ensure reactivity for legacy session observers */
    })

    updateSessionInfo(instanceId, sessionId)
    refreshPermissionsForSession(instanceId, sessionId)
  }
}

function handleSessionUpdate(instanceId: string, event: EventSessionUpdated): void {
  const info = event.properties?.info
  if (!info) return

  const compactingFlag = info.time?.compacting
  const isCompacting = typeof compactingFlag === "number" ? compactingFlag > 0 : Boolean(compactingFlag)
  setSessionCompactionState(instanceId, info.id, isCompacting)

  const instanceSessions = sessions().get(instanceId)
  if (!instanceSessions) return

  const existingSession = instanceSessions.get(info.id)

  if (!existingSession) {
    const newSession = {
      id: info.id,
      instanceId,
      title: info.title || "Untitled",
      parentId: info.parentID || null,
      agent: "",
      model: {
        providerId: "",
        modelId: "",
      },
      version: info.version || "0",
      time: info.time
        ? { ...info.time }
        : {
            created: Date.now(),
            updated: Date.now(),
          },
      messages: [],
      messagesInfo: new Map(),
    } as any

    setSessions((prev) => {
      const next = new Map(prev)
      const updated = new Map(prev.get(instanceId))
      updated.set(newSession.id, newSession)
      next.set(instanceId, updated)
      return next
    })
    setSessionRevertV2(instanceId, info.id, info.revert ?? null)

    console.log(`[SSE] New session created: ${info.id}`, newSession)
  } else {
    const mergedTime = {
      ...existingSession.time,
      ...(info.time ?? {}),
    }
    if (!info.time?.updated) {
      mergedTime.updated = Date.now()
    }

    const updatedSession = {
      ...existingSession,
      title: info.title || existingSession.title,
      time: mergedTime,
      revert: info.revert
        ? {
            messageID: info.revert.messageID,
            partID: info.revert.partID,
            snapshot: info.revert.snapshot,
            diff: info.revert.diff,
          }
        : existingSession.revert,
    }

    setSessions((prev) => {
      const next = new Map(prev)
      const updated = new Map(prev.get(instanceId))
      updated.set(existingSession.id, updatedSession)
      next.set(instanceId, updated)
      return next
    })
    setSessionRevertV2(instanceId, info.id, info.revert ?? null)
  }
}

function handleSessionIdle(_instanceId: string, event: EventSessionIdle): void {
  const sessionId = event.properties?.sessionID
  if (!sessionId) return

  console.log(`[SSE] Session idle: ${sessionId}`)
}

function handleSessionCompacted(instanceId: string, event: EventSessionCompacted): void {
  const sessionID = event.properties?.sessionID
  if (!sessionID) return

  console.log(`[SSE] Session compacted: ${sessionID}`)

  setSessionCompactionState(instanceId, sessionID, false)

  withSession(instanceId, sessionID, (session) => {
    const time = { ...(session.time ?? {}) }
    time.compacting = 0
    session.time = time
  })

  loadMessages(instanceId, sessionID, true).catch(console.error)

  const instanceSessions = sessions().get(instanceId)
  const session = instanceSessions?.get(sessionID)
  const label = session?.title?.trim() ? session.title : sessionID
  const instanceFolder = instances().get(instanceId)?.folder ?? instanceId
  const instanceName = instanceFolder.split(/[\\/]/).filter(Boolean).pop() ?? instanceFolder

  showToastNotification({
    title: instanceName,
    message: `Session ${label ? `"${label}"` : sessionID} was compacted`,
    variant: "info",
    duration: 10000,
  })
}

function handleSessionError(_instanceId: string, event: EventSessionError): void {
  const error = event.properties?.error
  console.error(`[SSE] Session error:`, error)

  let message = "Unknown error"

  if (error) {
    if ("data" in error && error.data && typeof error.data === "object" && "message" in error.data) {
      message = error.data.message as string
    } else if ("message" in error && typeof error.message === "string") {
      message = error.message
    }
  }

  showAlertDialog(`Error: ${message}`, {
    title: "Session error",
    variant: "error",
  })
}

function handleMessageRemoved(instanceId: string, event: MessageRemovedEvent): void {
  const sessionID = event.properties?.sessionID
  if (!sessionID) return

  console.log(`[SSE] Message removed from session ${sessionID}, reloading messages`)
  loadMessages(instanceId, sessionID, true).catch(console.error)
}

function handleMessagePartRemoved(instanceId: string, event: MessagePartRemovedEvent): void {
  const sessionID = event.properties?.sessionID
  if (!sessionID) return

  console.log(`[SSE] Message part removed from session ${sessionID}, reloading messages`)
  loadMessages(instanceId, sessionID, true).catch(console.error)
}

function handleTuiToast(_instanceId: string, event: TuiToastEvent): void {
  const payload = event?.properties
  if (!payload || typeof payload.message !== "string" || typeof payload.variant !== "string") return
  if (!payload.message.trim()) return

  const variant: ToastVariant = ALLOWED_TOAST_VARIANTS.has(payload.variant as ToastVariant)
    ? (payload.variant as ToastVariant)
    : "info"

  showToastNotification({
    title: typeof payload.title === "string" ? payload.title : undefined,
    message: payload.message,
    variant,
    duration: typeof payload.duration === "number" ? payload.duration : undefined,
  })
}

function handlePermissionUpdated(instanceId: string, event: EventPermissionUpdated): void {
  const permission = event.properties
  if (!permission) return

  console.log(`[SSE] Permission updated: ${permission.id} (${permission.type})`)
  addPermissionToQueue(instanceId, permission)
  upsertPermissionV2(instanceId, permission)
}

function handlePermissionReplied(instanceId: string, event: EventPermissionReplied): void {
  const { permissionID } = event.properties
  if (!permissionID) return

  console.log(`[SSE] Permission replied: ${permissionID}`)
  removePermissionFromQueue(instanceId, permissionID)
  removePermissionV2(instanceId, permissionID)
}

export {
  handleMessagePartRemoved,
  handleMessageRemoved,
  handleMessageUpdate,
  handlePermissionReplied,
  handlePermissionUpdated,
  handleSessionCompacted,
  handleSessionError,
  handleSessionIdle,
  handleSessionUpdate,
  handleTuiToast,
}