import "dart:convert";
import "dart:io";

import "package:auto_route/auto_route.dart";
import "package:file_picker/file_picker.dart";
import "package:flutter/material.dart";
import "package:flutter/services.dart";
import "package:flutter_riverpod/flutter_riverpod.dart";
import "package:share_plus/share_plus.dart";

import "package:smol_mail/data/providers/providers.dart";
import "package:smol_mail/presentation/routes/app_router.gr.dart";
import "package:smol_mail/presentation/theme/app_colors.dart";
import "package:smol_mail/shared/utils/snackbar.dart";
import "package:smol_mail/smol/crypto.dart";
import "package:smol_mail/smol/errors.dart";
import "package:smol_mail/smol/proto.dart";

/// Identity card, server pins, rotation and the wipe. The seed is the only
/// secret; revealing it is always an explicit action.
@RoutePage()
class SettingsScreen extends ConsumerStatefulWidget {
  const SettingsScreen({super.key});

  @override
  ConsumerState<SettingsScreen> createState() => _SettingsScreenState();
}

class _SettingsScreenState extends ConsumerState<SettingsScreen> {
  bool seedShown = false;
  final hostController = TextEditingController();
  final keyController = TextEditingController();
  final addressController = TextEditingController();
  final tokenController = TextEditingController();

  @override
  void dispose() {
    hostController.dispose();
    keyController.dispose();
    addressController.dispose();
    tokenController.dispose();
    super.dispose();
  }

  void _showError(Object error) {
    if (!mounted) return;
    showErrorSnackBar(context,
        error is SmolError ? error.message : "Something went wrong!");
  }

  Future<void> _register() async {
    final client = ref.read(clientProvider);
    try {
      await client.registerAccount(addressController.text,
          token: tokenController.text.trim());
      ref.read(revisionProvider.notifier).bump();
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(content: Text("registered")),
        );
      }
    } catch (err) {
      _showError(err);
    }
  }

  // Mail, once fetched, exists only on this device — the server deletes it as
  // it is picked up (SPEC.md §5). This backs up inbox, sent mail, contacts and
  // pinned servers into one shareable file; never the seed.
  Future<void> _export() async {
    final data = ref.read(storeProvider).exportData();
    final stamp = DateTime.now().toIso8601String().substring(0, 10);
    final file = File("${Directory.systemTemp.path}/smolmail-export-$stamp.json");
    await file.writeAsString(jsonEncode(data));
    await SharePlus.instance.share(ShareParams(
        files: [XFile(file.path)], text: "kirakira backup $stamp"));
    if (mounted) {
      final messages = (data["inbox"] as List).length + (data["sent"] as List).length;
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text("exported $messages messages, "
            "${(data["contacts"] as Map).length} contacts, "
            "${(data["servers"] as Map).length} server keys")),
      );
    }
  }

  Future<void> _import() async {
    final files = await FilePicker.pickFiles(
        type: FileType.custom, allowedExtensions: ["json"]);
    final path = files.isEmpty ? null : files.single.path;
    if (path == null) return;
    try {
      final data = jsonDecode(File(path).readAsStringSync()) as Map;
      final summary = await ref.read(storeProvider).importData(data);
      ref.read(revisionProvider.notifier).bump();
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text("imported: $summary")),
        );
      }
    } on Exception catch (err) {
      _showError(err);
    } on TypeError catch (err) {
      _showError(err);
    }
  }

  // Bind an address this seed was already registered under, without REGISTER.
  Future<void> _recall() async {
    final client = ref.read(clientProvider);
    try {
      final addr = await client.recallAccount(addressController.text);
      ref.read(revisionProvider.notifier).bump();
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text("recalled ${addr.short}")),
        );
      }
    } catch (err) {
      _showError(err);
    }
  }

  Future<void> _rotate() async {
    final client = ref.read(clientProvider);
    final confirmed = await showDialog<bool>(
      context: context,
      builder: (ctx) => AlertDialog(
        backgroundColor: Theme.of(context).extension<AppColors>()!.cardFill,
        title: const Text("Rotate the identity key?"),
        content: const Text(
            "Contacts accept the change from the signed chain. The old key is kept, "
            "since mail sealed to it stays readable with nothing else."),
        actions: [
          TextButton(
              onPressed: () => Navigator.of(ctx).pop(false),
              child: const Text("Cancel")),
          TextButton(
              onPressed: () => Navigator.of(ctx).pop(true),
              child: const Text("Rotate")),
        ],
      ),
    );
    if (confirmed != true) return;
    try {
      final fresh = await client.rotateIdentity();
      ref.read(revisionProvider.notifier).bump();
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text("rotated; new key ${b32encode(fresh.publicKey)}")),
        );
      }
    } catch (err) {
      _showError(err);
    }
  }

  Future<void> _wipe() async {
    final client = ref.read(clientProvider);
    final confirmed = await showDialog<bool>(
      context: context,
      builder: (ctx) => AlertDialog(
        backgroundColor: Theme.of(context).extension<AppColors>()!.cardFill,
        title: const Text("Wipe everything?"),
        content: const Text(
            "Deletes the identity, every pinned key and every stored message from "
            "this device. Mail left on servers stays there."),
        actions: [
          TextButton(
              onPressed: () => Navigator.of(ctx).pop(false),
              child: const Text("Cancel")),
          TextButton(
              onPressed: () => Navigator.of(ctx).pop(true),
              child: const Text("Wipe")),
        ],
      ),
    );
    if (confirmed != true) return;
    await client.wipe();
    ref.read(revisionProvider.notifier).bump();
    if (mounted) {
      AutoRouter.of(context).replace(OnboardingRoute());
    }
  }

  @override
  Widget build(BuildContext context) {
    final store = ref.watch(storeProvider);
    final me = ref.watch(identityProvider);
    final account = ref.watch(accountProvider);
    if (me == null) return Scaffold(appBar: AppBar(title: const Text("Settings")));

    final seedHex = hex(me.seed);
    final share = account?.uri(me.publicKey);
    final pins = store.allPins();

    return Scaffold(
      appBar: AppBar(title: const Text("Settings")),
      body: ListView(
        padding: const EdgeInsets.all(20),
        children: [
          _card(
            context,
            children: [
              Text("fingerprint", style: Theme.of(context).textTheme.labelSmall),
              Text(fingerprint(me.publicKey)),
              const SizedBox(height: 15),
              Text("address", style: Theme.of(context).textTheme.labelSmall),
              Text(account?.short ?? "(not registered)"),
              const SizedBox(height: 15),
              Text("share", style: Theme.of(context).textTheme.labelSmall),
              Row(
                children: [
                  Expanded(
                    child: Text(
                      share ?? "(register to get a shareable address)",
                      overflow: TextOverflow.ellipsis,
                    ),
                  ),
                  if (share != null)
                    IconButton(
                      icon: const Icon(Icons.copy, size: 18),
                      onPressed: () =>
                          Clipboard.setData(ClipboardData(text: share)),
                    ),
                ],
              ),
            ],
          ),
          const SizedBox(height: 20),
          _card(
            context,
            borderColor: Theme.of(context).colorScheme.error,
            children: [
              Text("seed", style: Theme.of(context).textTheme.labelSmall),
              Row(
                children: [
                  Expanded(
                    child: SelectableText(
                      seedShown ? seedHex : "•" * 64,
                      style: Theme.of(context).textTheme.bodySmall,
                    ),
                  ),
                  TextButton(
                    onPressed: () =>
                        setState(() => seedShown = !seedShown),
                    child: Text(seedShown ? "hide" : "reveal"),
                  ),
                  IconButton(
                    icon: const Icon(Icons.copy, size: 18),
                    onPressed: () =>
                        Clipboard.setData(ClipboardData(text: seedHex)),
                  ),
                ],
              ),
              Text(
                "back this seed up; it is the only secret",
                style: Theme.of(context)
                    .textTheme
                    .labelSmall!
                    .copyWith(color: Theme.of(context).colorScheme.error),
              ),
              const SizedBox(height: 10),
              Text(
                  "retired keys: ${store.identities().length - 1} (kept to read old mail)",
                  style: Theme.of(context).textTheme.labelSmall),
            ],
          ),
          const SizedBox(height: 30),
          const Divider(height: 1),
          const SizedBox(height: 20),
          Text("pinned servers", style: Theme.of(context).textTheme.titleMedium),
          const SizedBox(height: 10),
          for (final (host, key) in pins)
            ListTile(
              contentPadding: EdgeInsets.zero,
              title: Text(host),
              subtitle: Text(
                b32encode(key),
                overflow: TextOverflow.ellipsis,
                style: Theme.of(context).textTheme.labelSmall,
              ),
              trailing: IconButton(
                icon: const Icon(Icons.delete_outline, size: 18),
                onPressed: () {
                  store.unpinServer(host);
                  ref.read(revisionProvider.notifier).bump();
                  setState(() {});
                },
              ),
            ),
          if (pins.isEmpty)
            Text("no pinned servers", style: Theme.of(context).textTheme.labelSmall),
          const SizedBox(height: 10),
          TextField(
            controller: hostController,
            decoration: InputDecoration(
              labelText: "Host",
              filled: true,
              fillColor: Theme.of(context).extension<AppColors>()!.cardFill,
            ),
          ),
          const SizedBox(height: 10),
          TextField(
            controller: keyController,
            decoration: InputDecoration(
              labelText: "Server public key (base32)",
              filled: true,
              fillColor: Theme.of(context).extension<AppColors>()!.cardFill,
            ),
          ),
          const SizedBox(height: 10),
          TextButton(
            onPressed: () {
              try {
                ref
                    .read(clientProvider)
                    .pinServer(hostController.text, keyController.text);
                keyController.clear();
                setState(() {});
              } on SmolError catch (err) {
                _showError(err);
              } catch (err) {
                _showError(err);
              }
            },
            child: const Text("Pin server"),
          ),
          if (account == null) ...[
            const SizedBox(height: 30),
            const Divider(height: 1),
            const SizedBox(height: 20),
            Text("register an address",
                style: Theme.of(context).textTheme.titleMedium),
            const SizedBox(height: 10),
            TextField(
              controller: addressController,
              decoration: InputDecoration(
                labelText: "Address",
                hintText: "you@example.org[:1961]",
                filled: true,
                fillColor: Theme.of(context).extension<AppColors>()!.cardFill,
              ),
            ),
            const SizedBox(height: 10),
            TextField(
              controller: tokenController,
              decoration: InputDecoration(
                labelText: "Invite token (optional)",
                filled: true,
                fillColor: Theme.of(context).extension<AppColors>()!.cardFill,
              ),
            ),
            const SizedBox(height: 10),
            TextButton(
              onPressed: _register,
              child: const Text("Register"),
            ),
            TextButton(
              onPressed: _recall,
              child: const Text("Already registered? Recall"),
            ),
          ],
          const SizedBox(height: 30),
          const Divider(height: 1),
          const SizedBox(height: 20),
          Text("backup", style: Theme.of(context).textTheme.titleMedium),
          const SizedBox(height: 5),
          Text(
            "Mail, once fetched, exists only on this device. Export backs up the "
            "inbox, sent mail, contacts and server pins — never the seed.",
            style: Theme.of(context).textTheme.labelSmall,
          ),
          const SizedBox(height: 10),
          Row(
            children: [
              TextButton.icon(
                onPressed: _export,
                icon: const Icon(Icons.share, size: 18),
                label: const Text("Export"),
              ),
              TextButton.icon(
                onPressed: _import,
                icon: const Icon(Icons.file_upload, size: 18),
                label: const Text("Import"),
              ),
            ],
          ),
          const SizedBox(height: 30),
          const Divider(height: 1),
          const SizedBox(height: 10),
          ListTile(
            contentPadding: EdgeInsets.zero,
            title: const Text("Rotate identity key"),
            trailing: const Icon(Icons.rotate_right),
            onTap: _rotate,
          ),
          ListTile(
            contentPadding: EdgeInsets.zero,
            title: Text("Wipe identity and messages",
                style: TextStyle(
                    color: Theme.of(context).colorScheme.error)),
            trailing: Icon(Icons.delete_forever,
                color: Theme.of(context).colorScheme.error),
            onTap: _wipe,
          ),
        ],
      ),
    );
  }

  Widget _card(BuildContext context,
      {required List<Widget> children, Color? borderColor}) {
    return Container(
      width: double.infinity,
      padding: const EdgeInsets.all(16),
      decoration: BoxDecoration(
        color: Theme.of(context).extension<AppColors>()!.cardFill,
        borderRadius: BorderRadius.circular(10),
        border: borderColor == null ? null : Border.all(color: borderColor),
      ),
      child: Column(crossAxisAlignment: CrossAxisAlignment.start, children: children),
    );
  }
}