// ───────────────────────────────────────────────
// Create Lead Page (/(dashboard)/leads/new)
// ───────────────────────────────────────────────
// Route: /leads/new
// Purpose: Form to create a new lead. Uses
//   react-hook-form + zod for validation.
//   On success, fires a notification and
//   redirects to the leads list.
// Layout: Back link, heading, Card with form
//   fields in a 2-col grid + textarea + user
//   assignment select.
// ───────────────────────────────────────────────

"use client"

import { useState, useEffect } from "react"
import { useRouter } from "next/navigation"
import Link from "next/link"
import { useForm } from "react-hook-form"
import { zodResolver } from "@hookform/resolvers/zod"
import * as z from "zod"
import { Button } from "@/components/ui/button"
import { Input } from "@/components/ui/input"
import { Textarea } from "@/components/ui/textarea"
import {
  Form,
  FormControl,
  FormField,
  FormItem,
  FormLabel,
  FormMessage,
} from "@/components/ui/form"
import {
  Select,
  SelectContent,
  SelectItem,
  SelectTrigger,
  SelectValue,
} from "@/components/ui/select"
import { Card, CardContent } from "@/components/ui/card"
import { ArrowLeft } from "lucide-react"
import { User } from "@/types"
import { useNotifications } from "@/providers/notification-provider"
import { LEAD_SOURCES, LEAD_STATUSES } from "@/lib/constants"

/** Zod schema for lead creation form validation. */
const leadFormSchema = z.object({
  companyName: z.string().min(1, "Company name is required"),
  contactName: z.string().min(1, "Contact name is required"),
  email: z.string().email("Invalid email address"),
  phone: z.string().optional(),
  source: z.string().optional(),
  description: z.string().optional(),
  status: z.string(),
  assignedUserId: z.string().optional(),
})

type LeadFormValues = z.infer<typeof leadFormSchema>

/**
 * CreateLeadPage
 * ──────────────
 * Zod-validated lead creation form. Fetches the
 * user list for lead assignment on mount. On
 * submit POSTs to /api/leads and navigates back.
 *
 * @returns Lead creation form layout.
 */
export default function CreateLeadPage() {
  const router = useRouter()
  const { addNotification } = useNotifications()
  const [saving, setSaving] = useState(false)
  const [users, setUsers] = useState<User[]>([])

  // ── Fetch available users for assignment ──
  useEffect(() => {
    fetch("/api/users")
      .then((r) => r.json())
      .then((data) => setUsers(data.users || []))
      .catch(() => {})
  }, [])

  const form = useForm<LeadFormValues>({
    resolver: zodResolver(leadFormSchema),
    defaultValues: {
      companyName: "",
      contactName: "",
      email: "",
      phone: "",
      source: "",
      description: "",
      status: "open",
      assignedUserId: "none",
    },
  })

  // ── Submit handler ──
  async function onSubmit(values: LeadFormValues) {
    setSaving(true)
    try {
      // Transform "none" sentinel value to null
      const payload = {
        ...values,
        assignedUserId: values.assignedUserId === "none" ? null : (values.assignedUserId ?? null),
      }
      const res = await fetch("/api/leads", {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify(payload),
      })
      if (!res.ok) throw new Error("Failed to create lead")
      const data = await res.json()
      // Notify other parts of the app
      addNotification("lead_created", "New Lead Created", `${values.companyName} — ${values.contactName}`, `/leads/${data.id}`)
      router.push("/leads")
    } catch (e) {
      console.error("Create lead error:", e)
    } finally {
      setSaving(false)
    }
  }

  return (
    <div className="space-y-6">
      {/* ── Back navigation ── */}
      <Link
        href="/leads"
        className="inline-flex items-center gap-1 text-sm text-muted-foreground hover:text-foreground transition-colors"
      >
        <ArrowLeft className="h-4 w-4" />
        Back to leads
      </Link>

      <div>
        <h1 className="text-2xl font-bold tracking-tight">Create New Lead</h1>
        <p className="mt-1 text-sm text-muted-foreground">Fill in the details to add a new lead.</p>
      </div>

      {/* ── Lead form ── */}
      <Card>
        <CardContent className="pt-6">
          <Form {...form}>
            <form onSubmit={form.handleSubmit(onSubmit)} className="space-y-4">
              <div className="grid grid-cols-2 gap-4">
                <FormField
                  control={form.control}
                  name="companyName"
                  render={({ field }) => (
                    <FormItem>
                      <FormLabel>Company Name</FormLabel>
                      <FormControl>
                        <Input placeholder="Acme Corp" {...field} />
                      </FormControl>
                      <FormMessage />
                    </FormItem>
                  )}
                />
                <FormField
                  control={form.control}
                  name="contactName"
                  render={({ field }) => (
                    <FormItem>
                      <FormLabel>Contact Name</FormLabel>
                      <FormControl>
                        <Input placeholder="John Doe" {...field} />
                      </FormControl>
                      <FormMessage />
                    </FormItem>
                  )}
                />
                <FormField
                  control={form.control}
                  name="email"
                  render={({ field }) => (
                    <FormItem>
                      <FormLabel>Email</FormLabel>
                      <FormControl>
                        <Input placeholder="john@acme.com" type="email" {...field} />
                      </FormControl>
                      <FormMessage />
                    </FormItem>
                  )}
                />
                <FormField
                  control={form.control}
                  name="phone"
                  render={({ field }) => (
                    <FormItem>
                      <FormLabel>Phone</FormLabel>
                      <FormControl>
                        <Input placeholder="(555) 123-4567" {...field} />
                      </FormControl>
                      <FormMessage />
                    </FormItem>
                  )}
                />
                <FormField
                  control={form.control}
                  name="source"
                  render={({ field }) => (
                    <FormItem>
                      <FormLabel>Source</FormLabel>
                      <Select onValueChange={field.onChange} defaultValue={field.value}>
                        <FormControl>
                          <SelectTrigger>
                            <SelectValue placeholder="Select source" />
                          </SelectTrigger>
                        </FormControl>
                        <SelectContent>
                          {LEAD_SOURCES.map((source) => (
                            <SelectItem key={source} value={source}>
                              {source}
                            </SelectItem>
                          ))}
                        </SelectContent>
                      </Select>
                      <FormMessage />
                    </FormItem>
                  )}
                />
                <FormField
                  control={form.control}
                  name="status"
                  render={({ field }) => (
                    <FormItem>
                      <FormLabel>Status</FormLabel>
                      <Select onValueChange={field.onChange} defaultValue={field.value}>
                        <FormControl>
                          <SelectTrigger>
                            <SelectValue placeholder="Select status" />
                          </SelectTrigger>
                        </FormControl>
                        <SelectContent>
                          {Object.entries(LEAD_STATUSES).map(([key, { label }]) => (
                            <SelectItem key={key} value={key}>
                              {label}
                            </SelectItem>
                          ))}
                        </SelectContent>
                      </Select>
                      <FormMessage />
                    </FormItem>
                  )}
                />
              </div>
              <FormField
                control={form.control}
                name="description"
                render={({ field }) => (
                  <FormItem>
                    <FormLabel>Description</FormLabel>
                    <FormControl>
                      <Textarea
                        placeholder="Brief description of the lead and their requirements..."
                        className="min-h-[100px]"
                        {...field}
                      />
                    </FormControl>
                    <FormMessage />
                  </FormItem>
                )}
              />
              <FormField
                control={form.control}
                name="assignedUserId"
                render={({ field }) => (
                  <FormItem>
                    <FormLabel>Assign To</FormLabel>
                    <Select onValueChange={field.onChange} defaultValue={field.value}>
                      <FormControl>
                        <SelectTrigger>
                          <SelectValue placeholder="Select user" />
                        </SelectTrigger>
                      </FormControl>
                      <SelectContent>
                        <SelectItem value="none">Unassigned</SelectItem>
                        {users.filter((u) => u.active).map((user) => (
                          <SelectItem key={user.id} value={user.id}>
                            {user.name} ({user.role})
                          </SelectItem>
                        ))}
                      </SelectContent>
                    </Select>
                    <FormMessage />
                  </FormItem>
                )}
              />
              {/* ── Submit / Cancel buttons ── */}
              <div className="flex items-center gap-3 pt-2">
                <Button type="submit" disabled={saving}>
                  {saving ? "Saving..." : "Create Lead"}
                </Button>
                <Button
                  type="button"
                  variant="outline"
                  onClick={() => router.push("/leads")}
                >
                  Cancel
                </Button>
              </div>
            </form>
          </Form>
        </CardContent>
      </Card>
    </div>
  )
}