'use client'

import React, { createContext, useContext, useReducer, useMemo } from 'react'
import type { CustomCatalogEntry, CustomCatalogs, CatalogId } from './catalog-manager/types'

// =============================================================================
// SIMPLIFIED STATE (Admin-Lehrer only needs catalog-manager state)
// =============================================================================

export interface SDKState {
  customCatalogs: CustomCatalogs
}

export type SDKAction =
  | { type: 'ADD_CUSTOM_CATALOG_ENTRY'; payload: CustomCatalogEntry }
  | { type: 'UPDATE_CUSTOM_CATALOG_ENTRY'; payload: { catalogId: CatalogId; entryId: string; data: Record<string, unknown> } }
  | { type: 'DELETE_CUSTOM_CATALOG_ENTRY'; payload: { catalogId: CatalogId; entryId: string } }
  | { type: 'SET_STATE'; payload: Partial<SDKState> }

export const initialState: SDKState = {
  customCatalogs: {},
}

// =============================================================================
// REDUCER
// =============================================================================

function sdkReducer(state: SDKState, action: SDKAction): SDKState {
  switch (action.type) {
    case 'ADD_CUSTOM_CATALOG_ENTRY': {
      const entry = action.payload
      const existing = state.customCatalogs[entry.catalogId] || []
      return {
        ...state,
        customCatalogs: {
          ...state.customCatalogs,
          [entry.catalogId]: [...existing, entry],
        },
      }
    }

    case 'UPDATE_CUSTOM_CATALOG_ENTRY': {
      const { catalogId, entryId, data } = action.payload
      const existing = state.customCatalogs[catalogId] || []
      return {
        ...state,
        customCatalogs: {
          ...state.customCatalogs,
          [catalogId]: existing.map(e =>
            e.id === entryId
              ? { ...e, data, updatedAt: new Date().toISOString() }
              : e
          ),
        },
      }
    }

    case 'DELETE_CUSTOM_CATALOG_ENTRY': {
      const { catalogId, entryId } = action.payload
      const existing = state.customCatalogs[catalogId] || []
      return {
        ...state,
        customCatalogs: {
          ...state.customCatalogs,
          [catalogId]: existing.filter(e => e.id !== entryId),
        },
      }
    }

    case 'SET_STATE': {
      return { ...state, ...action.payload }
    }

    default:
      return state
  }
}

// =============================================================================
// CONTEXT
// =============================================================================

interface SDKContextValue {
  state: SDKState
  dispatch: React.Dispatch<SDKAction>
}

const SDKContext = createContext<SDKContextValue | null>(null)

// =============================================================================
// PROVIDER
// =============================================================================

interface SDKProviderProps {
  children: React.ReactNode
}

export function SDKProvider({ children }: SDKProviderProps) {
  const [state, dispatch] = useReducer(sdkReducer, initialState)

  const value: SDKContextValue = useMemo(() => ({
    state,
    dispatch,
  }), [state, dispatch])

  return <SDKContext.Provider value={value}>{children}</SDKContext.Provider>
}

// =============================================================================
// HOOK
// =============================================================================

export function useSDK(): SDKContextValue {
  const context = useContext(SDKContext)
  if (!context) {
    throw new Error('useSDK must be used within SDKProvider')
  }
  return context
}

export { SDKContext }