import { create } from 'zustand'
import { libraryApi } from './api'
import type { DocumentMeta, DocumentUpdateRequest } from './types'

interface LibraryState {
  documents: DocumentMeta[]
  total: number
  isLoading: boolean
  error: string | null
  searchQuery: string
  
  // Selection
  selectedIds: Set<string>
  toggleSelection: (id: string) => void
  clearSelection: () => void
  selectAll: () => void

  // Actions
  fetchDocuments: (query?: string) => Promise<void>
  fetchTrash: () => Promise<void>
  uploadDocument: (file: File) => Promise<DocumentMeta>
  deleteDocument: (id: string, permanent?: boolean) => Promise<void>
  restoreDocument: (id: string) => Promise<void>
  bulkDelete: (permanent?: boolean) => Promise<void>
  bulkRestore: () => Promise<void>
  emptyTrash: () => Promise<void>
  setSearchQuery: (query: string) => void
  updateDocument: (id: string, data: DocumentUpdateRequest) => Promise<void>
}

function errorMessage(reason: unknown, fallback = 'Something went wrong.') {
  if (reason instanceof Error && reason.message) return reason.message;
  if (typeof reason === 'object' && reason !== null && 'error' in reason) {
    const error = reason.error;
    if (typeof error === 'object' && error !== null && 'message' in error && typeof error.message === 'string') {
      return error.message;
    }
  }
  return fallback;
}

export const useLibrary = create<LibraryState>((set, get) => ({
  documents: [],
  total: 0,
  isLoading: false,
  error: null,
  searchQuery: '',
  selectedIds: new Set(),

  toggleSelection: (id) => set((state) => {
    const newSelection = new Set(state.selectedIds)
    if (newSelection.has(id)) newSelection.delete(id)
    else newSelection.add(id)
    return { selectedIds: newSelection }
  }),

  clearSelection: () => set({ selectedIds: new Set() }),
  
  selectAll: () => set((state) => ({ 
    selectedIds: new Set(state.documents.map(d => d.id)) 
  })),

  setSearchQuery: (query) => set({ searchQuery: query }),

  fetchDocuments: async (query = '') => {
    set({ isLoading: true, error: null, searchQuery: query })
    try {
      const data = await libraryApi.getDocuments(query)
      set({ documents: data.items, total: data.total, isLoading: false })
    } catch (err: unknown) {
      set({ error: errorMessage(err), isLoading: false })
    }
  },

  fetchTrash: async () => {
    set({ isLoading: true, error: null, searchQuery: '' })
    try {
      const data = await libraryApi.getTrash()
      set({ documents: data.items, total: data.total, isLoading: false })
    } catch (err: unknown) {
      set({ error: errorMessage(err), isLoading: false })
    }
  },

  uploadDocument: async (file: File) => {
    set({ isLoading: true, error: null })
    try {
      const newDoc = await libraryApi.uploadDocument(file)
      set((state) => ({ 
        documents: [newDoc, ...state.documents],
        total: state.total + 1,
        isLoading: false 
      }))
      return newDoc
    } catch (err: unknown) {
      set({ error: errorMessage(err), isLoading: false })
      throw err
    }
  },

  deleteDocument: async (id: string, permanent = false) => {
    set({ isLoading: true, error: null })
    try {
      await libraryApi.deleteDocument(id, permanent)
      set((state) => ({
        documents: state.documents.filter(d => d.id !== id),
        total: state.total - 1,
        selectedIds: new Set(Array.from(state.selectedIds).filter(sid => sid !== id)),
        isLoading: false
      }))
    } catch (err: unknown) {
      set({ error: errorMessage(err), isLoading: false })
      throw err
    }
  },

  restoreDocument: async (id: string) => {
    set({ isLoading: true, error: null })
    try {
      await libraryApi.restoreDocument(id)
      set((state) => ({
        documents: state.documents.filter(d => d.id !== id),
        total: state.total - 1,
        selectedIds: new Set(Array.from(state.selectedIds).filter(sid => sid !== id)),
        isLoading: false
      }))
    } catch (err: unknown) {
      set({ error: errorMessage(err), isLoading: false })
      throw err
    }
  },

  bulkDelete: async (permanent = false) => {
    const { selectedIds } = get()
    if (selectedIds.size === 0) return

    set({ isLoading: true, error: null })
    try {
      if (permanent) {
        // Must delete one by one if permanent
        await Promise.all(Array.from(selectedIds).map(id => libraryApi.deleteDocument(id, true)))
      } else {
        await libraryApi.bulkDelete({ ids: Array.from(selectedIds) })
      }
      
      set((state) => ({
        documents: state.documents.filter(d => !state.selectedIds.has(d.id)),
        total: state.total - state.selectedIds.size,
        selectedIds: new Set(),
        isLoading: false
      }))
    } catch (err: unknown) {
      set({ error: errorMessage(err), isLoading: false })
      throw err
    }
  },

  bulkRestore: async () => {
    const { selectedIds } = get()
    if (selectedIds.size === 0) return

    set({ isLoading: true, error: null })
    try {
      await libraryApi.bulkRestore({ ids: Array.from(selectedIds) })
      set((state) => ({
        documents: state.documents.filter(d => !state.selectedIds.has(d.id)),
        total: state.total - state.selectedIds.size,
        selectedIds: new Set(),
        isLoading: false
      }))
    } catch (err: unknown) {
      set({ error: errorMessage(err), isLoading: false })
      throw err
    }
  },

  emptyTrash: async () => {
    set({ isLoading: true, error: null })
    try {
      await libraryApi.emptyTrash()
      set({
        documents: [],
        total: 0,
        selectedIds: new Set(),
        isLoading: false
      })
    } catch (err: unknown) {
      set({ error: errorMessage(err), isLoading: false })
      throw err
    }
  },

  updateDocument: async (id: string, data: DocumentUpdateRequest) => {
    set({ isLoading: true, error: null })
    try {
      const updatedDoc = await libraryApi.updateDocument(id, data)
      set((state) => ({
        documents: state.documents.map(d => d.id === id ? updatedDoc : d),
        isLoading: false
      }))
    } catch (err: unknown) {
      set({ error: errorMessage(err), isLoading: false })
      throw err
    }
  }
}))