import { For, createEffect, createMemo, on, onCleanup, onMount, Show, type JSX } from "solid-js"
import { createStore, produce } from "solid-js/store"
import { useNavigate, useParams } from "@solidjs/router"
import { Button } from "@opencode-ai/ui/button"
import { Icon } from "@opencode-ai/ui/icon"
import { IconButton } from "@opencode-ai/ui/icon-button"
import { DropdownMenu } from "@opencode-ai/ui/dropdown-menu"
import { Dialog } from "@opencode-ai/ui/dialog"
import { InlineInput } from "@opencode-ai/ui/inline-input"
import { SessionTurn } from "@opencode-ai/ui/session-turn"
import type { UserMessage } from "@opencode-ai/sdk/v2"
import { showToast } from "@opencode-ai/ui/toast"
import { shouldMarkBoundaryGesture, normalizeWheelDelta } from "@/pages/session/message-gesture"
import { SessionContextUsage } from "@/components/session-context-usage"
import { useDialog } from "@opencode-ai/ui/context/dialog"
import { useLanguage } from "@/context/language"
import { useSDK } from "@/context/sdk"
import { useSync } from "@/context/sync"

const boundaryTarget = (root: HTMLElement, target: EventTarget | null) => {
  const current = target instanceof Element ? target : undefined
  const nested = current?.closest("[data-scrollable]")
  if (!nested || nested === root) return root
  if (!(nested instanceof HTMLElement)) return root
  return nested
}

const markBoundaryGesture = (input: {
  root: HTMLDivElement
  target: EventTarget | null
  delta: number
  onMarkScrollGesture: (target?: EventTarget | null) => void
}) => {
  const target = boundaryTarget(input.root, input.target)
  if (target === input.root) {
    input.onMarkScrollGesture(input.root)
    return
  }
  if (
    shouldMarkBoundaryGesture({
      delta: input.delta,
      scrollTop: target.scrollTop,
      scrollHeight: target.scrollHeight,
      clientHeight: target.clientHeight,
    })
  ) {
    input.onMarkScrollGesture(input.root)
  }
}

export function MessageTimeline(props: {
  mobileChanges: boolean
  mobileFallback: JSX.Element
  scroll: { overflow: boolean; bottom: boolean }
  onResumeScroll: () => void
  setScrollRef: (el: HTMLDivElement | undefined) => void
  onScheduleScrollState: (el: HTMLDivElement) => void
  onAutoScrollHandleScroll: () => void
  onMarkScrollGesture: (target?: EventTarget | null) => void
  hasScrollGesture: () => boolean
  isDesktop: boolean
  onScrollSpyScroll: () => void
  onAutoScrollInteraction: (event: MouseEvent) => void
  centered: boolean
  setContentRef: (el: HTMLDivElement) => void
  turnStart: number
  onRenderEarlier: () => void
  historyMore: boolean
  historyLoading: boolean
  onLoadEarlier: () => void
  renderedUserMessages: UserMessage[]
  anchor: (id: string) => string
  onRegisterMessage: (el: HTMLDivElement, id: string) => void
  onUnregisterMessage: (id: string) => void
  onFirstTurnMount?: () => void
  lastUserMessageID?: string
}) {
  let touchGesture: number | undefined

  const params = useParams()
  const navigate = useNavigate()
  const sdk = useSDK()
  const sync = useSync()
  const dialog = useDialog()
  const language = useLanguage()

  const sessionKey = createMemo(() => `${params.dir}${params.id ? "/" + params.id : ""}`)
  const sessionID = createMemo(() => params.id)
  const info = createMemo(() => {
    const id = sessionID()
    if (!id) return
    return sync.session.get(id)
  })
  const titleValue = createMemo(() => info()?.title)
  const parentID = createMemo(() => info()?.parentID)
  const showHeader = createMemo(() => !!(titleValue() || parentID()))

  const [title, setTitle] = createStore({
    draft: "",
    editing: false,
    saving: false,
    menuOpen: false,
    pendingRename: false,
  })
  let titleRef: HTMLInputElement | undefined

  const errorMessage = (err: unknown) => {
    if (err && typeof err === "object" && "data" in err) {
      const data = (err as { data?: { message?: string } }).data
      if (data?.message) return data.message
    }
    if (err instanceof Error) return err.message
    return language.t("common.requestFailed")
  }

  createEffect(
    on(
      sessionKey,
      () => setTitle({ draft: "", editing: false, saving: false, menuOpen: false, pendingRename: false }),
      { defer: true },
    ),
  )

  const openTitleEditor = () => {
    if (!sessionID()) return
    setTitle({ editing: true, draft: titleValue() ?? "" })
    requestAnimationFrame(() => {
      titleRef?.focus()
      titleRef?.select()
    })
  }

  const closeTitleEditor = () => {
    if (title.saving) return
    setTitle({ editing: false, saving: false })
  }

  const saveTitleEditor = async () => {
    const id = sessionID()
    if (!id) return
    if (title.saving) return

    const next = title.draft.trim()
    if (!next || next === (titleValue() ?? "")) {
      setTitle({ editing: false, saving: false })
      return
    }

    setTitle("saving", true)
    await sdk.client.session
      .update({ sessionID: id, title: next })
      .then(() => {
        sync.set(
          produce((draft) => {
            const index = draft.session.findIndex((s) => s.id === id)
            if (index !== -1) draft.session[index].title = next
          }),
        )
        setTitle({ editing: false, saving: false })
      })
      .catch((err) => {
        setTitle("saving", false)
        showToast({
          title: language.t("common.requestFailed"),
          description: errorMessage(err),
        })
      })
  }

  const navigateAfterSessionRemoval = (sessionID: string, parentID?: string, nextSessionID?: string) => {
    if (params.id !== sessionID) return
    if (parentID) {
      navigate(`/${params.dir}/session/${parentID}`)
      return
    }
    if (nextSessionID) {
      navigate(`/${params.dir}/session/${nextSessionID}`)
      return
    }
    navigate(`/${params.dir}/session`)
  }

  const archiveSession = async (sessionID: string) => {
    const session = sync.session.get(sessionID)
    if (!session) return

    const sessions = sync.data.session ?? []
    const index = sessions.findIndex((s) => s.id === sessionID)
    const nextSession = index === -1 ? undefined : (sessions[index + 1] ?? sessions[index - 1])

    await sdk.client.session
      .update({ sessionID, time: { archived: Date.now() } })
      .then(() => {
        sync.set(
          produce((draft) => {
            const index = draft.session.findIndex((s) => s.id === sessionID)
            if (index !== -1) draft.session.splice(index, 1)
          }),
        )
        navigateAfterSessionRemoval(sessionID, session.parentID, nextSession?.id)
      })
      .catch((err) => {
        showToast({
          title: language.t("common.requestFailed"),
          description: errorMessage(err),
        })
      })
  }

  const deleteSession = async (sessionID: string) => {
    const session = sync.session.get(sessionID)
    if (!session) return false

    const sessions = (sync.data.session ?? []).filter((s) => !s.parentID && !s.time?.archived)
    const index = sessions.findIndex((s) => s.id === sessionID)
    const nextSession = index === -1 ? undefined : (sessions[index + 1] ?? sessions[index - 1])

    const result = await sdk.client.session
      .delete({ sessionID })
      .then((x) => x.data)
      .catch((err) => {
        showToast({
          title: language.t("session.delete.failed.title"),
          description: errorMessage(err),
        })
        return false
      })

    if (!result) return false

    sync.set(
      produce((draft) => {
        const removed = new Set<string>([sessionID])

        const byParent = new Map<string, string[]>()
        for (const item of draft.session) {
          const parentID = item.parentID
          if (!parentID) continue
          const existing = byParent.get(parentID)
          if (existing) {
            existing.push(item.id)
            continue
          }
          byParent.set(parentID, [item.id])
        }

        const stack = [sessionID]
        while (stack.length) {
          const parentID = stack.pop()
          if (!parentID) continue

          const children = byParent.get(parentID)
          if (!children) continue

          for (const child of children) {
            if (removed.has(child)) continue
            removed.add(child)
            stack.push(child)
          }
        }

        draft.session = draft.session.filter((s) => !removed.has(s.id))
      }),
    )

    navigateAfterSessionRemoval(sessionID, session.parentID, nextSession?.id)
    return true
  }

  const navigateParent = () => {
    const id = parentID()
    if (!id) return
    navigate(`/${params.dir}/session/${id}`)
  }

  function DialogDeleteSession(props: { sessionID: string }) {
    const name = createMemo(() => sync.session.get(props.sessionID)?.title ?? language.t("command.session.new"))
    const handleDelete = async () => {
      await deleteSession(props.sessionID)
      dialog.close()
    }

    return (
      <Dialog title={language.t("session.delete.title")} fit>
        <div class="flex flex-col gap-4 pl-6 pr-2.5 pb-3">
          <div class="flex flex-col gap-1">
            <span class="text-14-regular text-text-strong">
              {language.t("session.delete.confirm", { name: name() })}
            </span>
          </div>
          <div class="flex justify-end gap-2">
            <Button variant="ghost" size="large" onClick={() => dialog.close()}>
              {language.t("common.cancel")}
            </Button>
            <Button variant="primary" size="large" onClick={handleDelete}>
              {language.t("session.delete.button")}
            </Button>
          </div>
        </div>
      </Dialog>
    )
  }

  return (
    <Show
      when={!props.mobileChanges}
      fallback={<div class="relative h-full overflow-hidden">{props.mobileFallback}</div>}
    >
      <div class="relative w-full h-full min-w-0">
        <div
          class="absolute left-1/2 -translate-x-1/2 bottom-6 z-[60] pointer-events-none transition-all duration-200 ease-out"
          classList={{
            "opacity-100 translate-y-0 scale-100": props.scroll.overflow && !props.scroll.bottom,
            "opacity-0 translate-y-2 scale-95 pointer-events-none": !props.scroll.overflow || props.scroll.bottom,
          }}
        >
          <button
            class="pointer-events-auto size-8 flex items-center justify-center rounded-full bg-background-base border border-border-base shadow-sm text-text-base hover:bg-background-stronger transition-colors"
            onClick={props.onResumeScroll}
          >
            <Icon name="arrow-down-to-line" />
          </button>
        </div>
        <div
          ref={props.setScrollRef}
          onWheel={(e) => {
            const root = e.currentTarget
            const delta = normalizeWheelDelta({
              deltaY: e.deltaY,
              deltaMode: e.deltaMode,
              rootHeight: root.clientHeight,
            })
            if (!delta) return
            markBoundaryGesture({ root, target: e.target, delta, onMarkScrollGesture: props.onMarkScrollGesture })
          }}
          onTouchStart={(e) => {
            touchGesture = e.touches[0]?.clientY
          }}
          onTouchMove={(e) => {
            const next = e.touches[0]?.clientY
            const prev = touchGesture
            touchGesture = next
            if (next === undefined || prev === undefined) return

            const delta = prev - next
            if (!delta) return

            const root = e.currentTarget
            markBoundaryGesture({ root, target: e.target, delta, onMarkScrollGesture: props.onMarkScrollGesture })
          }}
          onTouchEnd={() => {
            touchGesture = undefined
          }}
          onTouchCancel={() => {
            touchGesture = undefined
          }}
          onPointerDown={(e) => {
            if (e.target !== e.currentTarget) return
            props.onMarkScrollGesture(e.currentTarget)
          }}
          onScroll={(e) => {
            props.onScheduleScrollState(e.currentTarget)
            if (!props.hasScrollGesture()) return
            props.onAutoScrollHandleScroll()
            props.onMarkScrollGesture(e.currentTarget)
            if (props.isDesktop) props.onScrollSpyScroll()
          }}
          onClick={props.onAutoScrollInteraction}
          class="relative min-w-0 w-full h-full overflow-y-auto session-scroller"
          style={{ "--session-title-height": showHeader() ? "40px" : "0px" }}
        >
          <Show when={showHeader()}>
            <div
              classList={{
                "sticky top-0 z-30 bg-[linear-gradient(to_bottom,var(--background-stronger)_48px,transparent)]": true,
                "w-full": true,
                "pb-4": true,
                "pl-2 pr-3 md:pl-4 md:pr-3": true,
                "md:max-w-200 md:mx-auto 2xl:max-w-[1000px]": props.centered,
              }}
            >
              <div class="h-12 w-full flex items-center justify-between gap-2">
                <div class="flex items-center gap-1 min-w-0 flex-1 pr-3">
                  <Show when={parentID()}>
                    <IconButton
                      tabIndex={-1}
                      icon="arrow-left"
                      variant="ghost"
                      onClick={navigateParent}
                      aria-label={language.t("common.goBack")}
                    />
                  </Show>
                  <Show when={titleValue() || title.editing}>
                    <Show
                      when={title.editing}
                      fallback={
                        <h1
                          class="text-14-medium text-text-strong truncate grow-1 min-w-0 pl-2"
                          onDblClick={openTitleEditor}
                        >
                          {titleValue()}
                        </h1>
                      }
                    >
                      <InlineInput
                        ref={(el) => {
                          titleRef = el
                        }}
                        value={title.draft}
                        disabled={title.saving}
                        class="text-14-medium text-text-strong grow-1 min-w-0 pl-2 rounded-[6px]"
                        style={{ "--inline-input-shadow": "var(--shadow-xs-border-select)" }}
                        onInput={(event) => setTitle("draft", event.currentTarget.value)}
                        onKeyDown={(event) => {
                          event.stopPropagation()
                          if (event.key === "Enter") {
                            event.preventDefault()
                            void saveTitleEditor()
                            return
                          }
                          if (event.key === "Escape") {
                            event.preventDefault()
                            closeTitleEditor()
                          }
                        }}
                        onBlur={closeTitleEditor}
                      />
                    </Show>
                  </Show>
                </div>
                <Show when={sessionID()}>
                  {(id) => (
                    <div class="shrink-0 flex items-center gap-3">
                      <SessionContextUsage placement="bottom" />
                      <DropdownMenu
                        gutter={4}
                        placement="bottom-end"
                        open={title.menuOpen}
                        onOpenChange={(open) => setTitle("menuOpen", open)}
                      >
                        <DropdownMenu.Trigger
                          as={IconButton}
                          icon="dot-grid"
                          variant="ghost"
                          class="size-6 rounded-md data-[expanded]:bg-surface-base-active"
                          aria-label={language.t("common.moreOptions")}
                        />
                        <DropdownMenu.Portal>
                          <DropdownMenu.Content
                            style={{ "min-width": "104px" }}
                            onCloseAutoFocus={(event) => {
                              if (!title.pendingRename) return
                              event.preventDefault()
                              setTitle("pendingRename", false)
                              openTitleEditor()
                            }}
                          >
                            <DropdownMenu.Item
                              onSelect={() => {
                                setTitle("pendingRename", true)
                                setTitle("menuOpen", false)
                              }}
                            >
                              <DropdownMenu.ItemLabel>{language.t("common.rename")}</DropdownMenu.ItemLabel>
                            </DropdownMenu.Item>
                            <DropdownMenu.Item onSelect={() => void archiveSession(id())}>
                              <DropdownMenu.ItemLabel>{language.t("common.archive")}</DropdownMenu.ItemLabel>
                            </DropdownMenu.Item>
                            <DropdownMenu.Separator />
                            <DropdownMenu.Item
                              onSelect={() => dialog.show(() => <DialogDeleteSession sessionID={id()} />)}
                            >
                              <DropdownMenu.ItemLabel>{language.t("common.delete")}</DropdownMenu.ItemLabel>
                            </DropdownMenu.Item>
                          </DropdownMenu.Content>
                        </DropdownMenu.Portal>
                      </DropdownMenu>
                    </div>
                  )}
                </Show>
              </div>
            </div>
          </Show>

          <div
            ref={props.setContentRef}
            role="log"
            class="flex flex-col gap-12 items-start justify-start pb-16 transition-[margin]"
            classList={{
              "w-full": true,
              "md:max-w-200 md:mx-auto 2xl:max-w-[1000px]": props.centered,
              "mt-0.5": props.centered,
              "mt-0": !props.centered,
            }}
          >
            <Show when={props.turnStart > 0}>
              <div class="w-full flex justify-center">
                <Button variant="ghost" size="large" class="text-12-medium opacity-50" onClick={props.onRenderEarlier}>
                  {language.t("session.messages.renderEarlier")}
                </Button>
              </div>
            </Show>
            <Show when={props.historyMore}>
              <div class="w-full flex justify-center">
                <Button
                  variant="ghost"
                  size="large"
                  class="text-12-medium opacity-50"
                  disabled={props.historyLoading}
                  onClick={props.onLoadEarlier}
                >
                  {props.historyLoading
                    ? language.t("session.messages.loadingEarlier")
                    : language.t("session.messages.loadEarlier")}
                </Button>
              </div>
            </Show>
            <For each={props.renderedUserMessages}>
              {(message) => {
                if (import.meta.env.DEV && props.onFirstTurnMount) {
                  onMount(() => props.onFirstTurnMount?.())
                }

                return (
                  <div
                    id={props.anchor(message.id)}
                    data-message-id={message.id}
                    ref={(el) => {
                      props.onRegisterMessage(el, message.id)
                      onCleanup(() => props.onUnregisterMessage(message.id))
                    }}
                    classList={{
                      "min-w-0 w-full max-w-full": true,
                      "md:max-w-200 2xl:max-w-[1000px]": props.centered,
                    }}
                  >
                    <SessionTurn
                      sessionID={sessionID() ?? ""}
                      messageID={message.id}
                      lastUserMessageID={props.lastUserMessageID}
                      classes={{
                        root: "min-w-0 w-full relative",
                        content: "flex flex-col justify-between !overflow-visible",
                        container: "w-full px-4 md:px-6",
                      }}
                    />
                  </div>
                )
              }}
            </For>
          </div>
        </div>
      </div>
    </Show>
  )
}