import type { Session } from "@opencode-ai/sdk/v2/client"
import { createSimpleContext } from "@opencode-ai/ui/context"
import { base64Encode } from "@opencode-ai/core/util/encode"
import { createStore, produce } from "solid-js/store"
import { Persist, persisted, removePersisted, draftPersistedKeys } from "@/utils/persist"
import { ServerConnection, useServer } from "./server"
import { createEffect, startTransition } from "solid-js"
import { useLocation, useNavigate, useParams } from "@solidjs/router"
import { usePlatform } from "./platform"
import { uuid } from "@/utils/uuid"
import { SessionTabsRemovedDetail } from "@/components/titlebar-session-events"

export type SessionTab = {
  type: "session"
  server: ServerConnection.Key
  dirBase64: string
  sessionId: string
}

export type DraftTab = {
  type: "draft"
  draftID: string
  server: ServerConnection.Key
  directory: string
  worktree?: string
}

export type Tab = SessionTab | DraftTab

type RecentTab = {
  key?: string
}

export const draftHref = (draftID: string) => `/new-session?draftId=${encodeURIComponent(draftID)}`

export const tabHref = (tab: Tab) =>
  tab.type === "draft" ? draftHref(tab.draftID) : `/${tab.dirBase64}/session/${tab.sessionId}`

export const tabKey = (tab: Tab) => (tab.type === "draft" ? `draft:${tab.draftID}` : `${tab.server}\n${tabHref(tab)}`)

export function sessionHasOpenTab(tabs: Tab[], server: ServerConnection.Key, session: Session) {
  const dirBase64 = base64Encode(session.directory)
  return tabs.some(
    (tab) =>
      tab.type === "session" && tab.server === server && tab.dirBase64 === dirBase64 && tab.sessionId === session.id,
  )
}

export const { use: useTabs, provider: TabsProvider } = createSimpleContext({
  name: "Tabs",
  gate: false,
  init: () => {
    const server = useServer()
    const platform = usePlatform()
    const fallback = server.key
    const [store, setStore, _, ready] = persisted(
      {
        ...Persist.global("tabs"),
        migrate: (value: unknown) => {
          if (!Array.isArray(value)) return value
          return value.map((tab) => {
            if (!tab || typeof tab !== "object" || "server" in tab) return tab
            return { ...tab, server: fallback }
          })
        },
      },
      createStore<Tab[]>([]),
    )
    const [recent, setRecent, , recentReady] = persisted(Persist.global("tabs.recent"), createStore<RecentTab>({}))

    const params = useParams()
    const navigate = useNavigate()
    const location = useLocation()

    const closing = new Set<string>()
    let recentWrite = 0
    let recentValue: string | undefined

    const recentKey = () => (recentWrite ? recentValue : recent.key)

    const setRecentKey = (key: string | undefined) => {
      const write = ++recentWrite
      recentValue = key
      if (recentReady()) {
        setRecent("key", key)
        return
      }
      void recentReady.promise?.then(() => {
        if (write === recentWrite) setRecent("key", key)
      })
    }

    const removeDraftPersisted = (draftID: string) => {
      for (const key of draftPersistedKeys()) removePersisted(Persist.draft(draftID, key), platform)
    }

    createEffect(() => {
      if (!ready() || !recentReady()) return
      const servers = new Set(server.list.map(ServerConnection.key))
      const next = store.filter((tab) => servers.has(tab.server))
      if (next.length !== store.length) setStore(() => next)
      if (recent.key && !next.some((tab) => tabKey(tab) === recent.key)) setRecentKey(undefined)
    })

    const navigateTab = (tab: Tab) => {
      const href = tabHref(tab)
      setRecentKey(tabKey(tab))
      if (tab.server === server.key) {
        navigate(href)
        return
      }
      void startTransition(() => {
        server.setActive(tab.server)
        navigate(href)
      })
    }

    const actions = {
      addSessionTab: (tab: Omit<SessionTab, "type">) => {
        const next = { type: "session" as const, ...tab }
        if (closing.has(tabKey(next))) return
        setStore(
          produce((tabs) => {
            if (tabs.some((item) => tabKey(item) === tabKey(next))) return
            tabs.push(next)
          }),
        )
      },
      draft(draftID: string) {
        const tab = store.find((item) => item.type === "draft" && item.draftID === draftID)
        if (!tab || tab.type !== "draft") throw new Error(`Draft not found: ${draftID}`)
        return tab
      },
      newDraft(draft: Omit<DraftTab, "type" | "draftID">, prompt?: string) {
        const draftID = uuid()
        setStore(
          produce((tabs) => {
            tabs.push({ type: "draft", draftID, ...draft })
          }),
        )
        navigate(prompt ? `${draftHref(draftID)}&prompt=${encodeURIComponent(prompt)}` : draftHref(draftID))
      },
      updateDraft(draftID: string, draft: Partial<Omit<DraftTab, "type" | "draftID">>) {
        setStore(
          (tab) => tab.type === "draft" && tab.draftID === draftID,
          produce((tab) => Object.assign(tab, draft)),
        )
      },
      promoteDraft(draftID: string, session: Omit<SessionTab, "type">) {
        // We're viewing this draft when /new-session?draftId=… points at it. Promoting
        // replaces the draft tab with a session tab, so the draft route would stop resolving
        // and fall back home. Navigate to the new session first so we leave /new-session
        // before the draft is removed from the store.
        const active = location.pathname === "/new-session" && location.query.draftId === draftID
        const next = { type: "session" as const, ...session }
        startTransition(() => {
          setStore(
            produce((tabs) => {
              const index = tabs.findIndex((tab) => tab.type === "draft" && tab.draftID === draftID)
              if (index !== -1) tabs[index] = next
            }),
          )
          if (recent.key === `draft:${draftID}`) setRecentKey(tabKey(next))
          if (active) navigateTab(next)
        })
        removeDraftPersisted(draftID)
      },
      removeTab: (index: number) => {
        const tab = store[index]
        if (!tab) return
        const key = tabKey(tab)
        const draftID = tab.type === "draft" ? tab.draftID : undefined
        const nextTab = store[index + 1] ?? store[index - 1]
        closing.add(key)
        void startTransition(() => {
          setStore(
            produce((tabs) => {
              tabs.splice(index, 1)
            }),
          )
          if (recent.key === key) setRecentKey(nextTab && tabKey(nextTab))
          if (nextTab) navigateTab(nextTab)
          else navigate("/")
        }).finally(() => closing.delete(key))
        if (draftID) removeDraftPersisted(draftID)
      },
      removeServer(key: ServerConnection.Key) {
        const drafts = store.flatMap((tab) => (tab.type === "draft" && tab.server === key ? [tab.draftID] : []))
        const removed = store.filter((tab) => tab.server === key).map(tabKey)
        setStore((tabs) => tabs.filter((tab) => tab.server !== key))
        if (recent.key && removed.includes(recent.key)) setRecentKey(undefined)
        for (const draftID of drafts) removeDraftPersisted(draftID)
        if (server.key === key) navigate("/")
      },
      removeSessions: (input: SessionTabsRemovedDetail) => {
        const removed = store
          .filter(
            (tab) =>
              tab.type === "session" &&
              tab.server === server.key &&
              atob(tab.dirBase64) === input.directory &&
              input.sessionIDs.includes(tab.sessionId),
          )
          .map(tabKey)
        void startTransition(() => {
          setStore(
            produce((tabs) => {
              const sessionIDs = new Set(input.sessionIDs)
              const currentHref =
                params.dir && params.id
                  ? tabHref({
                      type: "session",
                      server: server.key,
                      dirBase64: params.dir,
                      sessionId: params.id,
                    })
                  : undefined
              const currentIndex = currentHref
                ? tabs.findIndex(
                    (tab) => tab.type === "session" && tab.server === server.key && tabHref(tab) === currentHref,
                  )
                : -1
              const currentTab = tabs[currentIndex]
              const removedCurrent =
                currentTab?.type === "session" &&
                currentTab.server === server.key &&
                atob(currentTab.dirBase64) === input.directory &&
                sessionIDs.has(currentTab.sessionId)

              for (let i = tabs.length - 1; i >= 0; i--) {
                const tab = tabs[i]
                if (!tab || tab.type !== "session") continue
                if (tab.server !== server.key) continue
                if (atob(tab.dirBase64) !== input.directory) continue
                if (!sessionIDs.has(tab.sessionId)) continue
                tabs.splice(i, 1)
              }

              if (!removedCurrent) return
              const nextTab =
                tabs.slice(currentIndex).find((tab) => tab.type === "session") ??
                tabs.slice(0, currentIndex).findLast((tab) => tab.type === "session")
              if (nextTab) navigateTab(nextTab)
              else navigate("/")
            }),
          )
          if (recent.key && removed.includes(recent.key)) setRecentKey(undefined)
        })
      },
      select: navigateTab,
      remember(tab: Tab) {
        const key = tabKey(tab)
        if (recentKey() !== key) setRecentKey(key)
      },
      toggleHome(input: { home: boolean; current?: Tab }) {
        if (input.home) {
          const tab = store.find((tab) => tabKey(tab) === recentKey())
          if (tab) navigateTab(tab)
          return
        }
        if (input.current) {
          setRecentKey(tabKey(input.current))
          navigate("/")
          return
        }
        navigate("/")
      },
    }

    return { ...actions, store, ready, recentReady }
  },
})