//
// Copyright © 2024 Hardcore Engineering Inc.
//
// Licensed under the Eclipse Public License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License. You may
// obtain a copy of the License at https://www.eclipse.org/legal/epl-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//
// See the License for the specific language governing permissions and
// limitations under the License.
//

import { MeasureContext, systemAccountEmail } from '@hcengineering/core'
import { aiBotAccountEmail, AIBotTransferEvent } from '@hcengineering/ai-bot'
import { WorkspaceInfoRecord } from '@hcengineering/server-ai-bot'
import { getTransactorEndpoint } from '@hcengineering/server-client'
import { generateToken } from '@hcengineering/server-token'
import { WorkspaceLoginInfo } from '@hcengineering/account'
import OpenAI from 'openai'
import { encoding_for_model } from 'tiktoken'

import { WorkspaceClient } from './workspaceClient'
import { assignBotToWorkspace, getWorkspaceInfo } from './account'
import config from './config'
import { DbStorage } from './storage'

const POLLING_INTERVAL_MS = 5 * 1000 // 5 seconds
const CLOSE_INTERVAL_MS = 10 * 60 * 1000 // 10 minutes
const ASSIGN_WORKSPACE_DELAY_MS = 5 * 1000 // 5 secs
const MAX_ASSIGN_ATTEMPTS = 5

export class AIBotController {
  private readonly workspaces: Map<string, WorkspaceClient> = new Map<string, WorkspaceClient>()
  private readonly closeWorkspaceTimeouts: Map<string, NodeJS.Timeout> = new Map<string, NodeJS.Timeout>()
  private readonly connectingWorkspaces: Set<string> = new Set<string>()

  private readonly intervalId: NodeJS.Timeout

  readonly aiClient: OpenAI
  readonly encoding = encoding_for_model(config.OpenAIModel)

  assignTimeout: NodeJS.Timeout | undefined
  assignAttempts = 0

  constructor (
    readonly storage: DbStorage,
    private readonly ctx: MeasureContext
  ) {
    this.aiClient = new OpenAI({ apiKey: config.OpenAIKey })

    this.intervalId = setInterval(() => {
      void this.updateWorkspaceClients()
    }, POLLING_INTERVAL_MS)
  }

  async updateWorkspaceClients (): Promise<void> {
    const activeRecords = await this.storage.getActiveWorkspaces()

    for (const record of activeRecords) {
      const ws = record.workspace

      if (this.workspaces.has(ws)) {
        continue
      }

      if (this.connectingWorkspaces.has(ws)) {
        continue
      }

      await this.initWorkspaceClient(ws, record)
    }
  }

  async closeWorkspaceClient (workspace: string): Promise<void> {
    this.ctx.info('Closing workspace client: ', { workspace })

    const timeoutId = this.closeWorkspaceTimeouts.get(workspace)

    if (timeoutId !== undefined) {
      clearTimeout(timeoutId)
      this.closeWorkspaceTimeouts.delete(workspace)
    }

    await this.storage.inactiveWorkspace(workspace)

    const client = this.workspaces.get(workspace)

    if (client !== undefined) {
      await client.close()
      this.workspaces.delete(workspace)
    }
    this.connectingWorkspaces.delete(workspace)
  }

  private async getWorkspaceInfo (ws: string): Promise<WorkspaceLoginInfo | undefined> {
    const systemToken = generateToken(systemAccountEmail, { name: ws })
    for (let i = 0; i < 5; i++) {
      try {
        const info = await getWorkspaceInfo(systemToken)

        if (info == null) {
          this.ctx.warn('Cannot find workspace info', { workspace: ws })
          await wait(ASSIGN_WORKSPACE_DELAY_MS)
          continue
        }

        return info
      } catch (e) {
        this.ctx.error('Error during get workspace info:', { e })
        await wait(ASSIGN_WORKSPACE_DELAY_MS)
      }
    }
  }

  private async assignToWorkspace (workspace: string): Promise<void> {
    clearTimeout(this.assignTimeout)
    try {
      const info = await this.getWorkspaceInfo(workspace)

      if (info === undefined) {
        void this.closeWorkspaceClient(workspace)
        return
      }

      if (info.creating === true) {
        this.ctx.info('Workspace is creating -> waiting...', { workspace })
        this.assignTimeout = setTimeout(() => {
          void this.assignToWorkspace(workspace)
        }, ASSIGN_WORKSPACE_DELAY_MS)
        return
      }

      const result = await assignBotToWorkspace(workspace)
      this.ctx.info('Assign to workspace result: ', { result, workspace })
    } catch (e) {
      this.ctx.error('Error during assign workspace:', { e })
      if (this.assignAttempts < MAX_ASSIGN_ATTEMPTS) {
        this.assignAttempts++
        this.assignTimeout = setTimeout(() => {
          void this.assignToWorkspace(workspace)
        }, ASSIGN_WORKSPACE_DELAY_MS)
      } else {
        void this.closeWorkspaceClient(workspace)
      }
    }
  }

  async initWorkspaceClient (workspace: string, info: WorkspaceInfoRecord): Promise<void> {
    this.connectingWorkspaces.add(workspace)

    if (!this.workspaces.has(workspace)) {
      this.ctx.info('Listen workspace: ', { workspace })
      await this.assignToWorkspace(workspace)
      const token = generateToken(aiBotAccountEmail, { name: workspace })
      const endpoint = await getTransactorEndpoint(token)
      this.workspaces.set(
        workspace,
        new WorkspaceClient(endpoint, token, workspace, this, this.ctx.newChild(workspace, {}), info)
      )
    }

    const timeoutId = this.closeWorkspaceTimeouts.get(workspace)

    if (timeoutId !== undefined) {
      clearTimeout(timeoutId)
    }

    const newTimeoutId = setTimeout(() => {
      void this.closeWorkspaceClient(workspace)
    }, CLOSE_INTERVAL_MS)

    this.closeWorkspaceTimeouts.set(workspace, newTimeoutId)
    this.connectingWorkspaces.delete(workspace)
  }

  async transfer (event: AIBotTransferEvent): Promise<void> {
    const workspace = event.toWorkspace
    const info = await this.storage.getWorkspace(workspace)

    if (info === undefined) {
      this.ctx.error('Workspace info not found -> cannot transfer event', { workspace })
      return
    }

    await this.initWorkspaceClient(workspace, info)

    const wsClient = this.workspaces.get(workspace)

    if (wsClient === undefined) {
      return
    }

    await wsClient.transfer(event)
  }

  async close (): Promise<void> {
    clearInterval(this.intervalId)

    this.encoding.free()

    for (const workspace of this.workspaces.values()) {
      await workspace.close()
    }
    for (const timeoutId of this.closeWorkspaceTimeouts.values()) {
      clearTimeout(timeoutId)
    }
    this.workspaces.clear()
  }

  async updateAvatarInfo (workspace: string, path: string, lastModified: number): Promise<void> {
    await this.storage.updateWorkspace(workspace, { $set: { avatarPath: path, avatarLastModified: lastModified } })
  }
}

async function wait (delay: number): Promise<void> {
  await new Promise<void>((resolve) => {
    setTimeout(() => {
      resolve()
    }, delay)
  })
}