"use client"

import * as React from "react"
import { toast } from "sonner"

import { createMember, getMembers } from "@/lib/api/customers"
import { addSubscriptionMember, getSubscription } from "@/lib/api/subscriptions"
import { useMediaQuery } from "@/lib/use-media-query"
import { useMutation } from "@/lib/use-mutation"
import type { SubscriptionSummary } from "@/lib/models/subscription"
import { Button } from "@/components/ui/button"
import {
  Dialog,
  DialogContent,
  DialogDescription,
  DialogFooter,
  DialogHeader,
  DialogTitle,
} from "@/components/ui/dialog"
import { Input } from "@/components/ui/input"
import { Label } from "@/components/ui/label"
import {
  Select,
  SelectContent,
  SelectItem,
  SelectTrigger,
  SelectValue,
} from "@/components/ui/select"
import {
  Sheet,
  SheetContent,
  SheetDescription,
  SheetFooter,
  SheetHeader,
  SheetTitle,
} from "@/components/ui/sheet"
import { Spinner } from "@/components/ui/spinner"
import { Tabs, TabsContent, TabsList, TabsTrigger } from "@/components/ui/tabs"

interface AddGroupMembersDialogProps {
  open: boolean
  onOpenChange: (open: boolean) => void
  summary: SubscriptionSummary | null
  /** Called after a member is added so the caller can refresh. When a member was actually
   * attached (not the demo path), this also carries the freshly refetched subscription so
   * the caller can update its own copy (e.g. groupSummary) — without this, a caller that
   * reopens the dialog later would show a stale member count. */
  onChanged: (freshSummary?: SubscriptionSummary) => void
  /** Sandbox demo mode: mutate local state instead of calling the backend. */
  demo?: boolean
  /** Pre-computed eligible-members list for the "existing member" tab (parent owns the customer roster). */
  demoEligibleOptions?: { label: string; value: string }[]
  demoAttachExisting?: (subscriptionId: string, customerId: string) => void
  demoCreateAndAttach?: (subscriptionId: string, values: typeof EMPTY_NEW) => void
}

const EMPTY_NEW = {
  fullname: "",
  userName: "",
  email: "",
  phoneNumber: "",
  gender: "",
  birthday: "",
}

function AddGroupMembersDialog({
  open,
  onOpenChange,
  summary,
  onChanged,
  demo = false,
  demoEligibleOptions,
  demoAttachExisting,
  demoCreateAndAttach,
}: AddGroupMembersDialogProps) {
  const isDesktop = useMediaQuery("(min-width: 768px)")
  const [existingOptions, setExistingOptions] = React.useState<{ label: string; value: string }[]>([])
  const [selectedExisting, setSelectedExisting] = React.useState("")
  const [newValues, setNewValues] = React.useState(EMPTY_NEW)
  const { busy, run } = useMutation()
  const [prevOpen, setPrevOpen] = React.useState(open)
  // Cosmetic only ("Done" vs "Cancel") -- the actual count always comes straight from
  // `summary`, which is kept in sync with the server after every add (see afterAdd below).
  const [hasAdded, setHasAdded] = React.useState(false)

  const memberCount = summary?.members.length ?? 0
  const limit = summary?.memberLimit ?? 0
  const atLimit = memberCount >= limit

  if (open !== prevOpen) {
    setPrevOpen(open)
    if (open) {
      setSelectedExisting("")
      setNewValues(EMPTY_NEW)
    }
  }

  // The dialog now stays open across multiple adds (a Group plan's members are usually added
  // one at a time right after creation), so the "existing member" list needs to re-sync
  // whenever the live member count changes, not just once when the dialog first opens.
  React.useEffect(() => {
    if (!open) return
    if (demo) {
      setExistingOptions(demoEligibleOptions ?? [])
    } else {
      void loadEligible(summary)
    }
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [open, memberCount, demo, summary])

  async function loadEligible(current: SubscriptionSummary | null) {
    if (!current) return
    try {
      const members = await getMembers()
      const alreadyIn = new Set(current.members.map((m) => m.customerId))
      // Dedupe by customer; exclude those already in this subscription.
      const seen = new Set<string>()
      const options: { label: string; value: string }[] = []
      for (const row of members) {
        const id = row.fkCustomerId
        if (alreadyIn.has(id) || seen.has(id) || !row.customer) continue
        seen.add(id)
        options.push({ label: row.customer.cusName ?? row.customer.email ?? "Member", value: id })
      }
      setExistingOptions(options)
    } catch {
      // Non-fatal; the create-new tab still works.
    }
  }

  /** Re-fetches the subscription so `summary` (and the caller's own copy of it) reflects
   * the member just added, then refreshes the eligible-members list against that truth.
   * This is what keeps the "N/limit" count and the "full" gate correct -- a client-side
   * counter can't be trusted since the caller may reopen this dialog from stale data. */
  async function afterAdd() {
    setSelectedExisting("")
    setNewValues(EMPTY_NEW)
    setHasAdded(true)
    if (!summary) return
    if (demo) {
      onChanged()
      return
    }
    try {
      const fresh = await getSubscription(summary.subscriptionId)
      onChanged(fresh)
      void loadEligible(fresh)
    } catch {
      // Non-fatal; the count may lag until the dialog is reopened.
      onChanged()
    }
  }

  async function attachExisting() {
    if (!summary || !selectedExisting || busy) return
    if (demo) {
      demoAttachExisting?.(summary.subscriptionId, selectedExisting)
      toast.success("Member added to the plan")
      setSelectedExisting("")
      onChanged()
      return
    }
    try {
      await run(() => addSubscriptionMember(summary.subscriptionId, selectedExisting))
      toast.success("Member added to the plan")
      // Stay open instead of closing -- a Group plan usually needs several members added back
      // to back, and the "plan is full" state below takes over once the limit is reached.
      setSelectedExisting("")
      onChanged()
    } catch {
      // run() already toasted the real error.
    }
  }

  async function createAndAttach(e: React.FormEvent) {
    e.preventDefault()
    if (!summary || busy) return
    const v = newValues
    if (!v.fullname.trim() || !v.userName.trim() || !v.email.trim() || !v.phoneNumber.trim() || !v.gender) return
    if (demo) {
      demoCreateAndAttach?.(summary.subscriptionId, v)
      toast.success("Member created and added to the plan")
      setNewValues(EMPTY_NEW)
      onChanged()
      return
    }
    try {
      await run(async () => {
        const created = await createMember({
          fullname: v.fullname.trim(),
          userName: v.userName.trim(),
          email: v.email.trim(),
          mobileNumber: v.phoneNumber.trim(),
          gender: v.gender,
          birthday: v.birthday,
        })
        await addSubscriptionMember(summary.subscriptionId, created.customer.cusId)
      })
      toast.success("Member created and added to the plan")
      // Stay open instead of closing -- same reasoning as attachExisting above.
      setNewValues(EMPTY_NEW)
      onChanged()
    } catch {
      // run() already toasted the real error.
    }
  }

  function setNew<K extends keyof typeof EMPTY_NEW>(key: K, value: string) {
    setNewValues((n) => ({ ...n, [key]: value }))
  }

  const Footer = isDesktop ? DialogFooter : SheetFooter
  const footerClassName = isDesktop ? "-mx-4 -mt-3 -mb-4" : "flex-col-reverse"
  const buttonWidthClassName = isDesktop ? undefined : "w-full"

  const body = atLimit ? (
    <div className="flex flex-col items-center gap-4 py-6">
      <p className="text-center text-sm text-muted-foreground">
        This plan is full ({limit} members).
      </p>
      <Button type="button" className={buttonWidthClassName} onClick={() => onOpenChange(false)}>Done</Button>
    </div>
  ) : (
    <Tabs defaultValue="existing">
      <TabsList className="w-full">
        <TabsTrigger value="existing" className="flex-1">Existing member</TabsTrigger>
        <TabsTrigger value="new" className="flex-1">New member</TabsTrigger>
      </TabsList>

      <TabsContent value="existing" className="mt-3 flex flex-col gap-3">
        <div className="flex flex-col gap-1.5">
          <Label>Select a member</Label>
          <Select items={existingOptions} value={selectedExisting || null} onValueChange={(v) => setSelectedExisting(v ?? "")}>
            <SelectTrigger className="w-full"><SelectValue placeholder={existingOptions.length ? "Choose a member" : "No eligible members"} /></SelectTrigger>
            <SelectContent>{existingOptions.map((opt) => <SelectItem key={opt.value} value={opt.value}>{opt.label}</SelectItem>)}</SelectContent>
          </Select>
        </div>
        <Footer className={footerClassName}>
          <Button type="button" variant="outline" className={buttonWidthClassName} onClick={() => onOpenChange(false)}>{hasAdded ? "Done" : "Cancel"}</Button>
          <Button type="button" className={buttonWidthClassName} onClick={attachExisting} disabled={!selectedExisting || busy}>{busy && <Spinner className="size-4" />}Add to plan</Button>
        </Footer>
      </TabsContent>

      <TabsContent value="new" className="mt-3">
        <form onSubmit={createAndAttach} className="flex flex-col gap-3">
          <div className="flex flex-col gap-1.5"><Label htmlFor="gm-fullname">Full Name <span className="text-destructive">*</span></Label><Input id="gm-fullname" value={newValues.fullname} onChange={(e) => setNew("fullname", e.target.value)} required /></div>
          <div className="grid grid-cols-2 gap-3">
            <div className="flex flex-col gap-1.5"><Label htmlFor="gm-username">Username <span className="text-destructive">*</span></Label><Input id="gm-username" value={newValues.userName} onChange={(e) => setNew("userName", e.target.value)} required /></div>
            <div className="flex flex-col gap-1.5"><Label htmlFor="gm-phone">Phone <span className="text-destructive">*</span></Label><Input id="gm-phone" type="tel" value={newValues.phoneNumber} onChange={(e) => setNew("phoneNumber", e.target.value)} required /></div>
          </div>
          <div className="flex flex-col gap-1.5"><Label htmlFor="gm-email">Email <span className="text-destructive">*</span></Label><Input id="gm-email" type="email" value={newValues.email} onChange={(e) => setNew("email", e.target.value)} required /></div>
          <div className="grid grid-cols-2 gap-3">
            <div className="flex flex-col gap-1.5">
              <Label>Gender <span className="text-destructive">*</span></Label>
              <Select items={[{ label: "Male", value: "Male" }, { label: "Female", value: "Female" }, { label: "Other", value: "Other" }]} value={newValues.gender || null} onValueChange={(v) => setNew("gender", v ?? "")}>
                <SelectTrigger className="w-full"><SelectValue placeholder="Select" /></SelectTrigger>
                <SelectContent><SelectItem value="Male">Male</SelectItem><SelectItem value="Female">Female</SelectItem><SelectItem value="Other">Other</SelectItem></SelectContent>
              </Select>
            </div>
            <div className="flex flex-col gap-1.5"><Label htmlFor="gm-birthday">Birthday</Label><Input id="gm-birthday" type="date" value={newValues.birthday} onChange={(e) => setNew("birthday", e.target.value)} max={new Date().toISOString().slice(0, 10)} /></div>
          </div>
          <Footer className={footerClassName}>
            <Button type="button" variant="outline" className={buttonWidthClassName} onClick={() => onOpenChange(false)}>{hasAdded ? "Done" : "Cancel"}</Button>
            <Button type="submit" className={buttonWidthClassName} disabled={busy}>{busy && <Spinner className="size-4" />}Create & add</Button>
          </Footer>
        </form>
      </TabsContent>
    </Tabs>
  )
  if (isDesktop) {
    return (
      <Dialog open={open} onOpenChange={onOpenChange} disablePointerDismissal>
        <DialogContent className="max-h-[90vh] overflow-y-auto sm:max-w-md">
          <DialogHeader>
            <DialogTitle>Add group members</DialogTitle>
            <DialogDescription>
              {summary?.planName} · {memberCount}/{limit} members
            </DialogDescription>
          </DialogHeader>
          {body}
        </DialogContent>
      </Dialog>
    )
  }

  return (
    <Sheet open={open} onOpenChange={onOpenChange} disablePointerDismissal>
      <SheetContent
        side="bottom"
        className="max-h-[92vh] overflow-y-auto rounded-t-2xl pb-[calc(env(safe-area-inset-bottom)+1rem)]"
      >
        <SheetHeader>
          <SheetTitle>Add group members</SheetTitle>
          <SheetDescription>
            {summary?.planName} · {memberCount}/{limit} members
          </SheetDescription>
        </SheetHeader>
        <div className="px-4 pb-2">{body}</div>
      </SheetContent>
    </Sheet>
  )
}

export { AddGroupMembersDialog }