import {
  CALENDAR_API_BASE,
  type GoogleCalendarInviteParams,
  type GoogleCalendarInviteResponse,
} from '@/tools/google_calendar/types'
import type { ToolConfig } from '@/tools/types'

export const inviteTool: ToolConfig<GoogleCalendarInviteParams, GoogleCalendarInviteResponse> = {
  id: 'google_calendar_invite',
  name: 'Google Calendar Invite Attendees',
  description: 'Invite attendees to an existing Google Calendar event',
  version: '1.0.0',

  oauth: {
    required: true,
    provider: 'google-calendar',
  },

  params: {
    accessToken: {
      type: 'string',
      required: true,
      visibility: 'hidden',
      description: 'Access token for Google Calendar API',
    },
    calendarId: {
      type: 'string',
      required: false,
      visibility: 'user-or-llm',
      description: 'Google Calendar ID (e.g., primary or calendar@group.calendar.google.com)',
    },
    eventId: {
      type: 'string',
      required: true,
      visibility: 'user-or-llm',
      description: 'Google Calendar event ID to invite attendees to',
    },
    attendees: {
      type: 'array',
      required: true,
      visibility: 'user-or-llm',
      description: 'Array of attendee email addresses to invite',
    },
    sendUpdates: {
      type: 'string',
      required: false,
      visibility: 'user-only',
      description: 'How to send updates to attendees: all, externalOnly, or none',
    },
    replaceExisting: {
      type: 'boolean',
      required: false,
      visibility: 'user-only',
      description: 'Whether to replace existing attendees or add to them (defaults to false)',
    },
  },

  request: {
    url: (params: GoogleCalendarInviteParams) => {
      const calendarId = params.calendarId || 'primary'
      return `${CALENDAR_API_BASE}/calendars/${encodeURIComponent(calendarId)}/events/${encodeURIComponent(params.eventId)}`
    },
    method: 'GET',
    headers: (params: GoogleCalendarInviteParams) => ({
      Authorization: `Bearer ${params.accessToken}`,
      'Content-Type': 'application/json',
    }),
  },

  transformResponse: async (response: Response, params) => {
    const existingEvent = await response.json()

    // Validate required fields exist
    if (!existingEvent.start || !existingEvent.end || !existingEvent.summary) {
      throw new Error('Existing event is missing required fields (start, end, or summary)')
    }

    // Process new attendees - handle both string and array formats
    let newAttendeeList: string[] = []

    if (params?.attendees) {
      if (Array.isArray(params.attendees)) {
        // Already an array from block processing
        newAttendeeList = params.attendees.filter(
          (email: string) => email && email.trim().length > 0
        )
      } else if (
        typeof (params.attendees as any) === 'string' &&
        (params.attendees as any).trim().length > 0
      ) {
        // Fallback: process comma-separated string if block didn't convert it
        newAttendeeList = (params.attendees as any)
          .split(',')
          .map((email: string) => email.trim())
          .filter((email: string) => email.length > 0)
      }
    }

    // Calculate final attendees list
    const existingAttendees = existingEvent.attendees || []
    let finalAttendees: Array<any> = []

    // Handle replaceExisting properly - check for both boolean true and string "true"
    const shouldReplace =
      params?.replaceExisting === true || (params?.replaceExisting as any) === 'true'

    if (shouldReplace) {
      // Replace all attendees with just the new ones
      finalAttendees = newAttendeeList.map((email: string) => ({
        email,
        responseStatus: 'needsAction',
      }))
    } else {
      // Add to existing attendees (preserve all existing ones)

      // Start with ALL existing attendees - preserve them completely
      finalAttendees = [...existingAttendees]

      // Get set of existing emails for duplicate checking (case-insensitive)
      const existingEmails = new Set(
        existingAttendees.map((attendee: any) => attendee.email?.toLowerCase() || '')
      )

      // Add only new attendees that don't already exist
      for (const newEmail of newAttendeeList) {
        const emailLower = newEmail.toLowerCase()
        if (!existingEmails.has(emailLower)) {
          finalAttendees.push({
            email: newEmail,
            responseStatus: 'needsAction',
          })
        }
      }
    }

    // Use the complete existing event object and only modify the attendees field
    // This is crucial because the Google Calendar API update method "does not support patch semantics
    // and always updates the entire event resource" according to the documentation
    const updatedEvent = {
      ...existingEvent, // Start with the complete existing event to preserve all fields
      attendees: finalAttendees, // Only modify the attendees field
    }

    // Remove read-only fields that shouldn't be included in updates
    const readOnlyFields = [
      'id',
      'etag',
      'kind',
      'created',
      'updated',
      'htmlLink',
      'iCalUID',
      'sequence',
      'creator',
      'organizer',
    ]
    readOnlyFields.forEach((field) => {
      delete updatedEvent[field]
    })

    // Construct PUT URL with query parameters
    const calendarId = params?.calendarId || 'primary'
    const queryParams = new URLSearchParams()
    if (params?.sendUpdates !== undefined) {
      queryParams.append('sendUpdates', params.sendUpdates)
    }

    const queryString = queryParams.toString()
    const putUrl = `${CALENDAR_API_BASE}/calendars/${encodeURIComponent(calendarId)}/events/${encodeURIComponent(params?.eventId || '')}${queryString ? `?${queryString}` : ''}`

    // Send PUT request to update the event
    const putResponse = await fetch(putUrl, {
      method: 'PUT',
      headers: {
        Authorization: `Bearer ${params?.accessToken}`,
        'Content-Type': 'application/json',
      },
      body: JSON.stringify(updatedEvent),
    })

    // Handle the PUT response
    if (!putResponse.ok) {
      const errorData = await putResponse.json()
      throw new Error(errorData.error?.message || 'Failed to invite attendees to calendar event')
    }

    const data = await putResponse.json()
    const totalAttendees = data.attendees?.length || 0

    // Calculate how many new attendees were actually added
    let newAttendeesAdded = 0

    if (shouldReplace) {
      newAttendeesAdded = newAttendeeList.length
    } else {
      // Count how many of the new emails weren't already in the existing list
      const existingEmails = new Set(
        existingAttendees.map((attendee: any) => attendee.email?.toLowerCase() || '')
      )
      newAttendeesAdded = newAttendeeList.filter(
        (email) => !existingEmails.has(email.toLowerCase())
      ).length
    }

    // Improved messaging about email delivery
    let baseMessage: string
    if (shouldReplace) {
      baseMessage = `Successfully updated event "${data.summary}" with ${totalAttendees} attendee${totalAttendees !== 1 ? 's' : ''}`
    } else {
      if (newAttendeesAdded > 0) {
        baseMessage = `Successfully added ${newAttendeesAdded} new attendee${newAttendeesAdded !== 1 ? 's' : ''} to event "${data.summary}" (total: ${totalAttendees})`
      } else {
        baseMessage = `No new attendees added to event "${data.summary}" - all specified attendees were already invited (total: ${totalAttendees})`
      }
    }

    const emailNote =
      params?.sendUpdates !== 'none'
        ? ` Email invitations are being sent asynchronously - delivery may take a few minutes and depends on recipients' Google Calendar settings.`
        : ` No email notifications will be sent as requested.`

    const content = baseMessage + emailNote

    return {
      success: true,
      output: {
        content,
        metadata: {
          id: data.id,
          htmlLink: data.htmlLink,
          status: data.status,
          summary: data.summary,
          description: data.description,
          location: data.location,
          start: data.start,
          end: data.end,
          attendees: data.attendees,
          creator: data.creator,
          organizer: data.organizer,
        },
      },
    }
  },

  outputs: {
    content: {
      type: 'string',
      description: 'Attendee invitation confirmation message with email delivery status',
    },
    metadata: {
      type: 'json',
      description: 'Updated event metadata including attendee list and details',
    },
  },
}

interface GoogleCalendarInviteV2Response {
  success: boolean
  output: {
    id: string
    htmlLink?: string
    status?: string
    summary?: string
    description?: string
    location?: string
    start?: any
    end?: any
    attendees?: any
    creator?: any
    organizer?: any
  }
}

export const inviteV2Tool: ToolConfig<GoogleCalendarInviteParams, GoogleCalendarInviteV2Response> =
  {
    id: 'google_calendar_invite_v2',
    name: 'Google Calendar Invite Attendees',
    description:
      'Invite attendees to an existing Google Calendar event. Returns API-aligned fields only.',
    version: '2.0.0',
    oauth: inviteTool.oauth,
    params: inviteTool.params,
    request: inviteTool.request,
    transformResponse: async (response: Response, params) => {
      const existingEvent = await response.json()

      if (!existingEvent.start || !existingEvent.end || !existingEvent.summary) {
        throw new Error('Existing event is missing required fields (start, end, or summary)')
      }

      let newAttendeeList: string[] = []

      if (params?.attendees) {
        if (Array.isArray(params.attendees)) {
          newAttendeeList = params.attendees.filter(
            (email: string) => email && email.trim().length > 0
          )
        } else if (
          typeof (params.attendees as any) === 'string' &&
          (params.attendees as any).trim().length > 0
        ) {
          newAttendeeList = (params.attendees as any)
            .split(',')
            .map((email: string) => email.trim())
            .filter((email: string) => email.length > 0)
        }
      }

      const existingAttendees = existingEvent.attendees || []
      let finalAttendees: Array<any> = []

      const shouldReplace =
        params?.replaceExisting === true || (params?.replaceExisting as any) === 'true'

      if (shouldReplace) {
        finalAttendees = newAttendeeList.map((email: string) => ({
          email,
          responseStatus: 'needsAction',
        }))
      } else {
        finalAttendees = [...existingAttendees]

        const existingEmails = new Set(
          existingAttendees.map((attendee: any) => attendee.email?.toLowerCase() || '')
        )

        for (const newEmail of newAttendeeList) {
          const emailLower = newEmail.toLowerCase()
          if (!existingEmails.has(emailLower)) {
            finalAttendees.push({
              email: newEmail,
              responseStatus: 'needsAction',
            })
          }
        }
      }

      const updatedEvent = {
        ...existingEvent,
        attendees: finalAttendees,
      }

      const readOnlyFields = [
        'id',
        'etag',
        'kind',
        'created',
        'updated',
        'htmlLink',
        'iCalUID',
        'sequence',
        'creator',
        'organizer',
      ]
      readOnlyFields.forEach((field) => {
        delete updatedEvent[field]
      })

      const calendarId = params?.calendarId || 'primary'
      const queryParams = new URLSearchParams()
      if (params?.sendUpdates !== undefined) {
        queryParams.append('sendUpdates', params.sendUpdates)
      }

      const queryString = queryParams.toString()
      const putUrl = `${CALENDAR_API_BASE}/calendars/${encodeURIComponent(calendarId)}/events/${encodeURIComponent(params?.eventId || '')}${queryString ? `?${queryString}` : ''}`

      const putResponse = await fetch(putUrl, {
        method: 'PUT',
        headers: {
          Authorization: `Bearer ${params?.accessToken}`,
          'Content-Type': 'application/json',
        },
        body: JSON.stringify(updatedEvent),
      })

      if (!putResponse.ok) {
        const errorData = await putResponse.json()
        throw new Error(errorData.error?.message || 'Failed to invite attendees to calendar event')
      }

      const data = await putResponse.json()

      return {
        success: true,
        output: {
          id: data.id,
          htmlLink: data.htmlLink,
          status: data.status,
          summary: data.summary ?? null,
          description: data.description ?? null,
          location: data.location ?? null,
          start: data.start,
          end: data.end,
          attendees: data.attendees ?? null,
          creator: data.creator,
          organizer: data.organizer,
        },
      }
    },
    outputs: {
      id: { type: 'string', description: 'Event ID' },
      htmlLink: { type: 'string', description: 'Event link' },
      status: { type: 'string', description: 'Event status' },
      summary: { type: 'string', description: 'Event title', optional: true },
      description: { type: 'string', description: 'Event description', optional: true },
      location: { type: 'string', description: 'Event location', optional: true },
      start: { type: 'json', description: 'Event start' },
      end: { type: 'json', description: 'Event end' },
      attendees: { type: 'json', description: 'Event attendees', optional: true },
      creator: { type: 'json', description: 'Event creator' },
      organizer: { type: 'json', description: 'Event organizer' },
    },
  }
