import { safeLocalStorage, useParams } from 'common'
import { partition } from 'lodash'
import { type NextRouter } from 'next/router'
import {
  createContext,
  PropsWithChildren,
  useContext,
  useEffect,
  useState,
  type ComponentType,
} from 'react'
import { proxy, subscribe, useSnapshot } from 'valtio'

import { buildTableEditorUrl } from '@/components/grid/SupabaseGrid.utils'
import type { SqlSnippetSource } from '@/components/interfaces/SQLEditor/querySource'
import type { EditorType } from '@/components/layouts/editors/EditorsLayout.hooks'
import type { ENTITY_TYPE } from '@/data/entity-types/entity-type-constants'

export const editorEntityTypes = {
  table: ['r', 'v', 'm', 'f', 'p'],
  sql: ['sql'],
  explorer: ['notebook', 'query', 'chat'],
}

export type TabType = ENTITY_TYPE | 'sql' | 'notebook' | 'query' | 'chat' | 'explorer-home'

/** Fixed id for Explorer's pinned, non-closable Home tab. */
export const EXPLORER_HOME_TAB_ID = 'explorer-home'

/** Tab descriptor for Explorer's Home tab — shared by its trigger and its page. */
export const EXPLORER_HOME_TAB: Tab = {
  id: EXPLORER_HOME_TAB_ID,
  type: 'explorer-home',
  label: 'Home',
  isPreview: false,
  closable: false,
}

type CreateTabIdParams = {
  r: { id: number }
  v: { id: number }
  m: { id: number }
  f: { id: number }
  p: { id: number }
  sql: { id: string }
  notebook: { id: string }
  query: { id: string }
  chat: { id: string }
  schema: { schema: string }
  view: never
  function: never
  new: never
  'explorer-home': never
}

export interface Tab {
  id: string
  type: TabType
  label?: string
  metadata?: {
    schema?: string
    name?: string
    tableId?: number
    sqlId?: string
    notebookId?: string
    queryId?: string
    chatId?: string
    scrollTop?: number
    /**
     * For SQL tabs, which backend the snippet queries (`'database'` | `'logs'`),
     * so the tab can show the matching icon without re-fetching the snippet.
     * Absent on tabs persisted before this field existed — treat absent as
     * `'database'` and backfill from the loaded snippet (source is immutable, so
     * it never goes stale once set).
     */
    sqlSource?: SqlSnippetSource
  }
  isPreview?: boolean
  /**
   * Whether the tab can be closed by the user (close button, keyboard shortcut,
   * or a bulk close action). Defaults to `true` — absent on every tab except a
   * pinned default (e.g. Explorer's Home tab), which sets this `false`.
   */
  closable?: boolean
  createdAt?: Date
  updatedAt?: Date
}

/** Copy shown in the confirmation dialog before a close is allowed to proceed. */
export interface TabCloseConfirmation {
  title: string
  description: string
}

/**
 * Per-tab-type behavior and UI the tabs layout delegates to, so the layout
 * stays agnostic of what any given tab kind means. A domain (e.g. the SQL
 * editor) registers a handler for its tab type via `registerTabTypeHandler`;
 * tabs of types without a handler close with no extra behavior and show no
 * status indicator.
 */
export interface TabTypeHandler {
  /**
   * Cleanup to run when the user closes a tab of this type (e.g. discarding a
   * SQL snippet's unsaved local edits). Runs after the tab has been removed.
   */
  onClose?: (tab: Tab) => void
  /**
   * Whether closing these tabs needs user confirmation. Receives the whole set
   * of this type being closed (e.g. a bulk "Close Others") so the handler owns
   * the dialog copy, including wording it for one vs. many. Return the copy to
   * confirm first; return null/undefined to close immediately.
   */
  confirmClose?: (tabs: Tab[]) => TabCloseConfirmation | null | undefined
  /**
   * Optional component rendered inside the tab to show type-specific status
   * (e.g. a VS Code-style unsaved-changes dot for a SQL snippet). Owning the
   * component here keeps the layout agnostic of what "status" means per type and
   * lets the domain drive its own reactivity. Rendered only when it has
   * something to show; otherwise it should render nothing.
   */
  StatusIndicator?: ComponentType<{ tab: Tab }>
}

const MAX_RECENT_ITEMS = 8

export interface RecentItem {
  id: string
  type: TabType
  label: string
  timestamp: number
  metadata?: {
    schema?: string
    name?: string
    tableId?: number
    sqlId?: string
    notebookId?: string
    queryId?: string
    chatId?: string
    sqlSource?: SqlSnippetSource
  }
}

const RECENT_ITEMS_STORAGE_KEY = 'supabase_recent_items'
const getRecentItemsStorageKey = (ref: string) => `${RECENT_ITEMS_STORAGE_KEY}_${ref}`

function getSavedRecentItems(ref: string): RecentItem[] {
  if (!ref) return []

  const stored = safeLocalStorage.getItem(getRecentItemsStorageKey(ref))

  try {
    return JSON.parse(stored ?? '{"items": []}').items
  } catch (error) {
    return []
  }
}

const createDefaultTabsState = () => ({
  activeTab: null as string | null,
  openTabs: [] as string[],
  tabsMap: {} as Record<string, Tab>,
  previewTabId: undefined as string | undefined,
  recentItems: [],
})
const TABS_STORAGE_KEY = 'supabase_studio_tabs'
const getTabsStorageKey = (ref: string) => `${TABS_STORAGE_KEY}_${ref}`

function getSavedTabs(ref: string) {
  if (!ref) return createDefaultTabsState()

  const stored = safeLocalStorage.getItem(getTabsStorageKey(ref))

  if (!stored) return createDefaultTabsState()

  try {
    const parsed = JSON.parse(stored ?? JSON.stringify(createDefaultTabsState())) as ReturnType<
      typeof createDefaultTabsState
    >

    if (
      !parsed.openTabs ||
      !Array.isArray(parsed.openTabs) ||
      !parsed.tabsMap ||
      typeof parsed.tabsMap !== 'object'
    ) {
      return createDefaultTabsState()
    }

    return parsed
  } catch (error) {
    return createDefaultTabsState()
  }
}

const getRecentItemLabel = (tab: Pick<Tab, 'label' | 'metadata'>) =>
  tab.label || tab.metadata?.name || 'Untitled'

const syncRecentItemWithTab = (item: RecentItem, tab: Pick<Tab, 'label' | 'metadata'>) => {
  const nextLabel = getRecentItemLabel(tab)

  item.label = nextLabel
  item.metadata = {
    ...item.metadata,
    ...tab.metadata,
    name: nextLabel,
  }
}

export function createTabsState(projectRef: string) {
  const recentItems = getSavedRecentItems(projectRef)
  const { openTabs, activeTab, tabsMap, previewTabId } = getSavedTabs(projectRef)

  // Per-type behavior/UI, kept outside the Valtio proxy so handler closures
  // (which may capture non-serializable things like a React Query client or a
  // React component) are never proxied or persisted.
  const tabHandlers = new Map<TabType, TabTypeHandler>()

  const store = proxy({
    // RECENT ITEMS
    recentItems,

    addRecentItem: (tab: Tab) => {
      // Check if an item with the same ID already exists
      const existingItem = store.recentItems.find((item) => item.id === tab.id)

      if (existingItem) {
        // If it exists, update its timestamp
        existingItem.timestamp = Date.now()
        syncRecentItemWithTab(existingItem, tab)
        return // Exit the function
      }

      // If it doesn't exist, create and add a new item
      const recentItem: RecentItem = {
        id: tab.id, // Set the ID
        type: tab.type, // Set the type
        label: getRecentItemLabel(tab), // Set the label or default to 'Untitled'
        timestamp: Date.now(), // Set the current timestamp
        metadata: tab.metadata, // Set the metadata
      }

      // Add the new recent item to the beginning of the list
      store.recentItems.unshift(recentItem)

      // Ensure that there's only up to max of MAX_RECENT_ITEMS items per tab type
      const [itemsOfSameType, itemsOfDifferentType] = partition(store.recentItems, (item) => {
        if (editorEntityTypes.table.includes(item.type)) return item
      })
      store.recentItems = [...itemsOfSameType.slice(0, MAX_RECENT_ITEMS), ...itemsOfDifferentType]
    },
    clearRecentItems: () => {
      store.recentItems = []
    },
    removeRecentItem: (itemId: string) => {
      store.recentItems = store.recentItems.filter((item) => item.id !== itemId)
    },
    removeRecentItems: (itemIds: string[]) => {
      store.recentItems = store.recentItems.filter((item) => !itemIds.includes(item.id))
    },
    removeRecentItemsByType: (type: TabType) => {
      store.recentItems = store.recentItems.filter((item) => item.type !== type)
    },

    getRecentItemsByType: (type: TabType) => {
      return store.recentItems.filter((item) => item.type === type)
    },

    // TABS
    activeTab,
    openTabs,
    tabsMap,
    previewTabId,

    hasTab: (id: string) => {
      return !!store.tabsMap[id]
    },
    addTab: (tab: Tab) => {
      // If tab exists and is active, don't do anything
      if (store.tabsMap[tab.id] && store.activeTab === tab.id) {
        return
      }

      // If tab exists but isn't active, just make it active
      if (store.tabsMap[tab.id]) {
        store.activeTab = tab.id
        if (!tab.isPreview) store.addRecentItem(tab)
        return
      }

      // If this tab should be permanent, add it normally
      if (tab.isPreview === false) {
        store.openTabs = [...store.openTabs, tab.id]
        store.tabsMap[tab.id] = tab
        store.activeTab = tab.id
        // Add to recent items when creating permanent tab
        store.addRecentItem(tab)
        return
      }

      // Remove any existing preview tab
      if (store.previewTabId) {
        store.openTabs = store.openTabs.filter((id) => id !== store.previewTabId)
        delete store.tabsMap[store.previewTabId]
      }

      // Add new preview tab
      store.tabsMap[tab.id] = { ...tab, isPreview: true }
      store.openTabs = [...store.openTabs, tab.id]
      store.previewTabId = tab.id
      store.activeTab = tab.id
    },
    // Ensures a tab that's always present, first, and outside the draggable/
    // closable set (e.g. Explorer's Home tab) exists in the store, without
    // touching which tab is active. Safe to call from wherever the pinned
    // tab's trigger renders, regardless of which page currently owns focus.
    ensurePinnedTab: (tab: Tab) => {
      if (store.tabsMap[tab.id]) return
      store.tabsMap[tab.id] = tab
      store.openTabs = [tab.id, ...store.openTabs]
    },
    // Ensures a pinned tab exists (see ensurePinnedTab) and marks it active,
    // without recording it in Recent Items — it isn't content to revisit,
    // just a fixed destination. Call this from the page it represents, on
    // mount, mirroring how regular tabs call addTab from their own page.
    activatePinnedTab: (tab: Tab) => {
      store.ensurePinnedTab(tab)
      store.activeTab = tab.id
    },
    updateTab: (
      id: string,
      updates: { label?: string; scrollTop?: number; sqlSource?: SqlSnippetSource }
    ) => {
      const tab = store.tabsMap[id]
      if (!tab) return

      if ('label' in updates) {
        tab.label = updates.label
        // Keep the persisted name aligned with the visible label so browser titles
        // and tab state recover cleanly after entity renames.
        if (typeof updates.label === 'string' && tab.metadata) {
          tab.metadata.name = updates.label
        }

        const recentItem = store.recentItems.find((item) => item.id === id)
        if (recentItem) syncRecentItemWithTab(recentItem, tab)
      }
      if ('scrollTop' in updates && tab.metadata) {
        tab.metadata.scrollTop = updates.scrollTop
      }
      // Backfill the immutable source onto a tab (and its recent item) that
      // predates the field, so its icon resolves correctly once the snippet loads.
      if (updates.sqlSource !== undefined) {
        if (tab.metadata) tab.metadata.sqlSource = updates.sqlSource
        else tab.metadata = { sqlSource: updates.sqlSource }

        const recentItem = store.recentItems.find((item) => item.id === id)
        if (recentItem) syncRecentItemWithTab(recentItem, tab)
      }
    },
    // Function to remove a tab from the store
    // this is used for removing tabs from the localstorage state
    // for handling a manual tab removal with a close action, use handleTabClose()
    removeTab: (id: string) => {
      if (store.tabsMap[id]?.closable === false) return

      const idx = store.openTabs.indexOf(id)
      store.openTabs = store.openTabs.filter((tabId) => tabId !== id)
      delete store.tabsMap[id]

      // Clear the preview tab reference if the removed tab was the preview tab,
      // so it doesn't linger in (persisted) state pointing at a closed tab
      if (store.previewTabId === id) {
        store.previewTabId = undefined
      }

      // Update active tab if the removed tab was active
      if (id === store.activeTab) {
        store.activeTab = store.openTabs[idx - 1] || store.openTabs[idx + 1] || null
      }
    },

    // Function to remove multiple tabs from the store
    // this is used for removing tabs from the localstorage state
    // for handling a manual tab removal with a close action, use handleTabClose()
    removeTabs: (ids: string[]) => {
      if (!ids.length) return

      ids.forEach((id) => store.removeTab(id))
    },
    reorderTabs: (oldIndex: number, newIndex: number) => {
      const newOpenTabs = [...store.openTabs]
      const [removedTab] = newOpenTabs.splice(oldIndex, 1)
      newOpenTabs.splice(newIndex, 0, removedTab)
      store.openTabs = newOpenTabs
    },
    makeTabActive: (tabId: string) => {
      const tab = store.tabsMap[tabId]
      if (!tab) return
      store.activeTab = tab.id
    },
    makeTabPermanent: (tabId: string) => {
      const tab = store.tabsMap[tabId]

      if (tab?.isPreview) {
        tab.isPreview = false
        store.previewTabId = undefined
        // Add to recent items when preview tab becomes permanent
        store.addRecentItem(tab)
      }
    },
    makeActiveTabPermanent: () => {
      if (store.activeTab && store.tabsMap[store.activeTab]?.isPreview) {
        store.makeTabPermanent(store.activeTab)
        return true
      }
      return false
    },

    // TABS HANDLERS

    handleTabNavigation: (id: string, router: NextRouter) => {
      const tab = store.tabsMap[id]
      if (!tab) return

      store.activeTab = id

      // Add to recent items when navigating to a non-preview, non-new tab.
      // Pinned tabs (e.g. Explorer's Home) are a fixed destination, not content
      // to revisit, so they're excluded regardless of preview state.
      if (!tab.isPreview && tab.closable !== false) store.addRecentItem(tab)

      switch (tab.type) {
        case 'sql':
          const schema = (router.query.schema as string) || 'public'
          router.push(`/project/${router.query.ref}/sql/${tab.metadata?.sqlId}?schema=${schema}`)
          break
        case 'notebook':
          router.push(`/project/${router.query.ref}/explorer/notebook/${tab.metadata?.notebookId}`)
          break
        case 'query':
          router.push(`/project/${router.query.ref}/explorer/query/${tab.metadata?.queryId}`)
          break
        case 'chat':
          router.push(`/project/${router.query.ref}/explorer/chat/${tab.metadata?.chatId}`)
          break
        case 'explorer-home':
          router.push(`/project/${router.query.ref}/explorer`)
          break
        case 'r':
        case 'v':
        case 'm':
        case 'f':
        case 'p':
          router.push(
            buildTableEditorUrl({
              projectRef: router.query.ref as string,
              tableId: tab.metadata?.tableId!,
              schema: tab.metadata?.schema,
            })
          )
          break
      }
    },
    // TAB TYPE HANDLER REGISTRY
    //
    // Lets a domain own what a tab of its type means — how it closes and what
    // status it shows — without the layout having to know. Registered per tab
    // type; returns an unregister function.
    //
    // Bumped on every (un)register so components that render per-type UI (the
    // status indicator) re-render to pick up a handler registered after they
    // first rendered — handlers register in an effect, which runs after the
    // tabs first paint.
    handlerRegistrationVersion: 0,
    registerTabTypeHandler: (type: TabType, handler: TabTypeHandler) => {
      tabHandlers.set(type, handler)
      store.handlerRegistrationVersion++
      return () => {
        if (tabHandlers.get(type) === handler) {
          tabHandlers.delete(type)
          store.handlerRegistrationVersion++
        }
      }
    },

    // The status-indicator component registered for a tab type, if any. Read
    // `handlerRegistrationVersion` alongside this in render to stay reactive to
    // late registration.
    getTabStatusIndicator: (type: TabType) => tabHandlers.get(type)?.StatusIndicator,

    // The confirmation to show before closing the given tabs, or null if none
    // need confirming. Tabs are grouped by type and each type's handler is asked
    // about its own set (so it can word the copy for one vs. many); the first
    // handler that asks to confirm wins. The store authors no copy itself — that
    // stays a concern of the registering domain.
    getCloseConfirmation: (ids: string[]): TabCloseConfirmation | null => {
      const tabsByType = new Map<TabType, Tab[]>()
      for (const id of ids) {
        const tab = store.tabsMap[id]
        if (!tab) continue
        const group = tabsByType.get(tab.type)
        if (group) group.push(tab)
        else tabsByType.set(tab.type, [tab])
      }

      for (const [type, tabs] of tabsByType) {
        const confirmation = tabHandlers.get(type)?.confirmClose?.(tabs)
        if (confirmation) return confirmation
      }
      return null
    },

    // Close multiple tabs as an intentional user action, running each tab type's
    // close handler afterwards. Distinct from `removeTabs`, the low-level store
    // mutation used for re-keying (rename/move) and stale cleanup, which must
    // NOT trigger discard behavior.
    closeTabs: (ids: string[]) => {
      const closedTabs = ids
        .map((id) => store.tabsMap[id])
        .filter((tab): tab is Tab => tab !== undefined && tab.closable !== false)
      store.removeTabs(closedTabs.map((tab) => tab.id))
      closedTabs.forEach((tab) => tabHandlers.get(tab.type)?.onClose?.(tab))
    },

    handleTabClose: ({
      id,
      router,
      editor,
      onClose,
      onClearDashboardHistory,
    }: {
      id: string
      router: NextRouter
      editor?: EditorType
      onClose?: (id: string) => void
      onClearDashboardHistory: () => void
    }) => {
      const tabBeingClosed = store.tabsMap[id]

      const editorTabIds = (
        editor
          ? Object.values(store.tabsMap).filter((tab) =>
              editorEntityTypes[editor]?.includes(tab.type)
            )
          : []
      ).map((tab) => tab.id)
      const tabIndexBeingClosed = editorTabIds.indexOf(id)
      const isLastTabBeingClosed = tabIndexBeingClosed === editorTabIds.length - 1
      const nextTabId =
        editorTabIds.length === 1
          ? undefined
          : isLastTabBeingClosed
            ? editorTabIds[tabIndexBeingClosed - 1]
            : editorTabIds[tabIndexBeingClosed + 1]

      const { [id]: value, ...otherTabs } = store.tabsMap
      store.tabsMap = otherTabs

      if (tabBeingClosed) {
        const updatedOpenTabs = [...store.openTabs].filter((x) => x !== id)
        store.openTabs = updatedOpenTabs
      }

      // Remove the preview tab if it matches the tab being closed
      if (store.previewTabId === id) {
        store.previewTabId = undefined
      }

      // [Joshen] Only navigate away if we're closing the tab that's currently in focus
      if (store.activeTab === id || id === 'new') {
        if (nextTabId) {
          store.activeTab = nextTabId
          store.handleTabNavigation(nextTabId, router)
        } else {
          onClearDashboardHistory()

          // If no tabs of same type, go to the home of the current section
          switch (tabBeingClosed?.type) {
            case 'sql':
              router.push(`/project/${router.query.ref}/sql`)
              break
            case 'notebook':
            case 'query':
            case 'chat':
              router.push(`/project/${router.query.ref}/explorer`)
              break
            case 'r':
            case 'v':
            case 'm':
            case 'f':
            case 'p':
              router.push(`/project/${router.query.ref}/editor`)
              break
            default:
              router.push(`/project/${router.query.ref}/${editor === 'table' ? 'editor' : 'sql'}`)
          }
        }
      }

      onClose?.(id)

      // Run the tab type's registered close behavior (e.g. discard a SQL
      // snippet's unsaved edits). `tabBeingClosed` is captured before removal.
      if (tabBeingClosed) {
        tabHandlers.get(tabBeingClosed.type)?.onClose?.(tabBeingClosed)
      }
    },
    handleTabCloseAll: ({
      editor,
      router,
      onClearDashboardHistory,
    }: {
      editor: 'sql' | 'table' | 'explorer'
      router: NextRouter
      onClearDashboardHistory: () => void
    }) => {
      const tabsToClose = store.openTabs.filter((id) => {
        const tab = store.tabsMap[id]
        return tab !== undefined && editorEntityTypes[editor].includes(tab.type)
      })
      store.closeTabs(tabsToClose)
      onClearDashboardHistory()
      const editorPath = editor === 'table' ? 'editor' : editor
      router.push(`/project/${router.query.ref}/${editorPath}`)
    },
    handleTabDragEnd: (oldIndex: number, newIndex: number, tabId: string, router: NextRouter) => {
      // Make permanent if needed
      const draggedTab = store.tabsMap[tabId]
      if (draggedTab?.isPreview) {
        store.makeTabPermanent(tabId)
      }

      // Reorder tabs
      const newOpenTabs = [...store.openTabs]
      newOpenTabs.splice(oldIndex, 1)
      newOpenTabs.splice(newIndex, 0, tabId)

      store.openTabs = newOpenTabs
      store.activeTab = tabId

      // Handle navigation
      store.handleTabNavigation(tabId, router)
    },
  })

  return store
}

export type TabsState = ReturnType<typeof createTabsState>

export const TabsStateContext = createContext<TabsState>(createTabsState(''))

export const TabsStateContextProvider = ({ children }: PropsWithChildren) => {
  const { ref: projectRef } = useParams()
  const [state, setState] = useState(createTabsState(projectRef ?? ''))

  useEffect(() => {
    if (typeof window !== 'undefined' && !!projectRef) {
      setState(createTabsState(projectRef ?? ''))
    }
  }, [projectRef])

  useEffect(() => {
    if (typeof window !== 'undefined' && projectRef) {
      return subscribe(state, () => {
        safeLocalStorage.setItem(
          getTabsStorageKey(projectRef),
          JSON.stringify({
            activeTab: state.activeTab,
            openTabs: state.openTabs,
            tabsMap: state.tabsMap,
            previewTabId: state.previewTabId,
          })
        )
        safeLocalStorage.setItem(
          getRecentItemsStorageKey(projectRef),
          JSON.stringify({
            items: state.recentItems,
          })
        )
      })
    }
  }, [projectRef, state])

  return <TabsStateContext.Provider value={state}>{children}</TabsStateContext.Provider>
}

export const useTabsStateSnapshot = (options?: Parameters<typeof useSnapshot>[1]) => {
  const state = useContext(TabsStateContext)
  return useSnapshot(state, options)
}

export function createTabId<T extends TabType>(type: T, params: CreateTabIdParams[T]): string {
  switch (type) {
    case 'r':
      return `r-${(params as CreateTabIdParams['r']).id}`
    case 'v':
      return `v-${(params as CreateTabIdParams['v']).id}`
    case 'm':
      return `m-${(params as CreateTabIdParams['m']).id}`
    case 'f':
      return `f-${(params as CreateTabIdParams['f']).id}`
    case 'p':
      return `p-${(params as CreateTabIdParams['p']).id}`
    case 'sql':
      return `sql-${(params as CreateTabIdParams['sql']).id}`
    case 'notebook':
      return `notebook-${(params as CreateTabIdParams['notebook']).id}`
    case 'query':
      return `query-${(params as CreateTabIdParams['query']).id}`
    case 'chat':
      return `chat-${(params as CreateTabIdParams['chat']).id}`
    default:
      return ''
  }
}