"use client";

import { useState } from "react";
import { useRouter } from "next/navigation";

interface DocFormProps {
  mode: "create" | "edit";
  slug?: string;
  secret: string; // injected server-side (never visible to the client JS bundle)
  initial?: {
    title?: string;
    body?: string;
    section?: "docs" | "writeups" | "research" | "notes";
    type?: "documentation" | "writeup" | "research" | "note";
    status?: "published" | "draft";
    tags?: string[];
    author?: string;
  };
}

const SECTION_OPTIONS = ["docs", "writeups", "research", "notes"] as const;
const TYPE_OPTIONS = ["documentation", "writeup", "research", "note"] as const;

export default function DocForm({ mode, slug, secret, initial }: DocFormProps) {
  const router = useRouter();
  const [loading, setLoading] = useState(false);
  const [error, setError] = useState<string | null>(null);

  const [title, setTitle] = useState(initial?.title ?? "");
  const [body, setBody] = useState(initial?.body ?? "");
  const [section, setSection] = useState(initial?.section ?? "docs");
  const [type, setType] = useState(initial?.type ?? "documentation");
  const [status, setStatus] = useState(initial?.status ?? "published");
  const [tags, setTags] = useState(initial?.tags?.join(", ") ?? "");
  const [author, setAuthor] = useState(initial?.author ?? "");

  const tagList = tags
    .split(",")
    .map((t) => t.trim())
    .filter(Boolean);

  async function handleSubmit(e: React.FormEvent) {
    e.preventDefault();
    setLoading(true);
    setError(null);

    const payload = {
      title,
      body,
      section,
      type,
      status,
      author,
      tags: tagList,
    };

    try {
      let res: Response;
      if (mode === "create") {
        const slugVal = slug ?? title.toLowerCase().replace(/[^a-z0-9]+/g, "-").replace(/^-+|-+$/g, "");
        res = await fetch("/api/docs", {
          method: "POST",
          headers: { "Content-Type": "application/json", "x-webhook-secret": secret },
          body: JSON.stringify({ slug: slugVal, ...payload }),
        });
      } else {
        const editSlug = slug ?? "";
        res = await fetch(`/api/docs/${editSlug}`, {
          method: "PUT",
          headers: { "Content-Type": "application/json", "x-webhook-secret": secret },
          body: JSON.stringify(payload),
        });
      }

      if (!res.ok) {
        const data = await res.json().catch(() => ({}));
        throw new Error(data.error ?? "Save failed");
      }

      const result = await res.json();
      router.push(result.doc?.slug ? `/${result.doc.slug}` : "/");
    } catch (err) {
      setError(err instanceof Error ? err.message : String(err));
    } finally {
      setLoading(false);
    }
  }

  return (
    <form onSubmit={handleSubmit} className="space-y-6 max-w-4xl mx-auto">
      {error && (
        <div className="p-4 bg-red-50 dark:bg-red-900/20 border border-red-200 dark:border-red-800 rounded text-red-800 dark:text-red-200">
          {error}
        </div>
      )}

      <div>
        <label className="block text-sm font-medium mb-1">Title</label>
        <input
          type="text"
          value={title}
          onChange={(e) => setTitle(e.target.value)}
          className="w-full px-3 py-2 border border-zinc-300 dark:border-zinc-700 rounded bg-white dark:bg-zinc-900"
          required
        />
      </div>

      <div>
        <label className="block text-sm font-medium mb-1">Slug</label>
        <input
          type="text"
          value={slug ?? ""}
          onChange={(e) => router.replace(`/docs/${section}/edit?slug=${e.target.value}`)}
          className="w-full px-3 py-2 border border-zinc-300 dark:border-zinc-700 rounded bg-zinc-50 dark:bg-zinc-800"
          placeholder={section}
        />
        <p className="text-xs text-zinc-500 mt-1">URL-safe path under the section (e.g. "websocket/contract").</p>
      </div>

      <div className="grid grid-cols-1 md:grid-cols-3 gap-4">
        <div>
          <label className="block text-sm font-medium mb-1">Section</label>
          <select
            value={section}
            onChange={(e) => setSection(e.target.value as typeof section)}
            className="w-full px-3 py-2 border border-zinc-300 dark:border-zinc-700 rounded bg-white dark:bg-zinc-900"
          >
            {SECTION_OPTIONS.map((s) => (
              <option key={s} value={s}>{s}</option>
            ))}
          </select>
        </div>
        <div>
          <label className="block text-sm font-medium mb-1">Type</label>
          <select
            value={type}
            onChange={(e) => setType(e.target.value as typeof type)}
            className="w-full px-3 py-2 border border-zinc-300 dark:border-zinc-700 rounded bg-white dark:bg-zinc-900"
          >
            {TYPE_OPTIONS.map((t) => (
              <option key={t} value={t}>{t}</option>
            ))}
          </select>
        </div>
        <div>
          <label className="block text-sm font-medium mb-1">Status</label>
          <select
            value={status}
            onChange={(e) => setStatus(e.target.value as typeof status)}
            className="w-full px-3 py-2 border border-zinc-300 dark:border-zinc-700 rounded bg-white dark:bg-zinc-900"
          >
            <option value="published">Published</option>
            <option value="draft">Draft</option>
          </select>
        </div>
      </div>

      <div>
        <label className="block text-sm font-medium mb-1">Tags</label>
        <input
          type="text"
          value={tags}
          onChange={(e) => setTags(e.target.value)}
          className="w-full px-3 py-2 border border-zinc-300 dark:border-zinc-700 rounded bg-white dark:bg-zinc-900"
          placeholder="comma, separated, tags"
        />
      </div>

      <div>
        <label className="block text-sm font-medium mb-1">Author</label>
        <input
          type="text"
          value={author}
          onChange={(e) => setAuthor(e.target.value)}
          className="w-fill px-3 py-2 border border-zinc-300 dark:border-zinc-700 rounded bg-white dark:bg-zinc-900"
        />
      </div>

      <div>
        <label className="block text-sm font-medium mb-1">Body (Markdown)</label>
        <textarea
          value={body}
          onChange={(e) => setBody(e.target.value)}
          className="w-full h-96 px-3 py-2 border border-zinc-300 dark:border-zinc-700 rounded bg-white dark:bg-zinc-900 font-mono text-sm"
          placeholder="# Heading&#10;&#10;Content here..."
        />
      </div>

      <div className="flex gap-3">
        <button
          type="submit"
          disabled={loading}
          className="px-4 py-2 bg-zinc-900 dark:bg-zinc-100 text-white dark:text-zinc-900 rounded hover:bg-zinc-800 disabled:opacity-50"
        >
          {loading ? "Saving..." : mode === "create" ? "Create" : "Update"}
        </button>
        <button
          type="button"
          onClick={() => router.back()}
          className="px-4 py-2 border border-zinc-300 dark:border-zinc-700 rounded hover:bg-zinc-100 dark:hover:bg-zinc-800"
        >
          Cancel
        </button>
      </div>
    </form>
  );
}