import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:go_router/go_router.dart';

import '../../core/format.dart';
import '../../core/models.dart';
import '../../core/providers.dart';
import '../../core/theme.dart';
import '../../widgets/ui.dart';
import 'shop_picker.dart';
import 'user_bits.dart';

class UserDetailScreen extends ConsumerWidget {
  const UserDetailScreen({super.key, required this.userId});
  final int userId;

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final user = ref.watch(userProvider(userId));
    final shops = ref.watch(activeShopsProvider).value ?? const <Shop>[];
    return Scaffold(
      body: SafeArea(
        child: asyncView(
          user,
          (u) => Column(
            children: [
              const ScreenHeader(
                title: 'User details',
                back: true,
                maxWidth: _maxW,
              ),
              Expanded(
                child: _Body(u: u, shops: shops),
              ),
            ],
          ),
          retry: () => ref.invalidate(userProvider(userId)),
        ),
      ),
    );
  }
}

const _maxW = 1040.0;

class _Body extends ConsumerWidget {
  const _Body({required this.u, required this.shops});
  final AppUser u;
  final List<Shop> shops;

  Future<void> _delete(BuildContext context, WidgetRef ref) async {
    final ok = await confirm(
      context,
      title: 'Delete ${u.username}?',
      body:
          'This permanently removes the account. Saved orders are kept. This action cannot be undone.',
      confirmLabel: 'Delete user',
    );
    if (!ok || !context.mounted) return;
    try {
      await mutate(ref, () => ref.read(apiProvider).deleteUser(u.id));
      if (!context.mounted) return;
      context.pop();
      toast(context, 'User deleted');
    } catch (e) {
      if (context.mounted) toast(context, errText(e));
    }
  }

  Future<void> _toggleActive(BuildContext context, WidgetRef ref) async {
    final deactivate = u.active;
    final ok = await confirm(
      context,
      title: deactivate
          ? 'Deactivate ${u.username}?'
          : 'Activate ${u.username}?',
      body: deactivate
          ? 'This user will no longer be able to sign in. Saved orders are kept.'
          : 'This user will be able to sign in again with their current password.',
      confirmLabel: deactivate ? 'Deactivate' : 'Activate',
      danger: deactivate,
    );
    if (!ok || !context.mounted) return;
    try {
      await mutate(
        ref,
        () => ref.read(apiProvider).updateUser(u.id, active: !deactivate),
      );
      if (context.mounted) {
        toast(context, deactivate ? 'User deactivated' : 'User activated');
      }
    } catch (e) {
      if (context.mounted) toast(context, errText(e));
    }
  }

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final mine = shops.where((s) => u.shopIds.contains(s.id)).toList();
    return PaneList(
      maxWidth: _maxW,
      breakpoint: 760,
      startFlex: 1,
      endFlex: 1,
      gap: S.s24,
      start: [
        _Profile(u: u),
        _Heading(
          'Shops',
          action: mine.isEmpty ? 'Assign shops' : 'Edit shops',
          onAction: () => _shopsSheet(context, ref),
        ),
        SrsCard(
          padding: EdgeInsets.zero,
          child: mine.isEmpty
              ? Padding(
                  padding: const EdgeInsets.all(S.s16),
                  child: Text(
                    'No shops yet. ${u.username} cannot see any orders or results until a shop is assigned.',
                    style: ts(13, c: C.muted, h: 1.45),
                  ),
                )
              : Column(
                  children: [
                    for (var i = 0; i < mine.length; i++) ...[
                      if (i > 0) const Divider(height: 1, color: C.border),
                      Padding(
                        padding: const EdgeInsets.symmetric(
                          horizontal: S.s16,
                          vertical: S.s12,
                        ),
                        child: Row(
                          children: [
                            CodeTile(mine[i].code, size: 40),
                            const SizedBox(width: S.s12),
                            Expanded(
                              child: Text(mine[i].name, style: ts(15, w: w6)),
                            ),
                          ],
                        ),
                      ),
                    ],
                  ],
                ),
        ),
      ],
      end: [
        const _Heading('Sign-in details'),
        SrsCard(
          padding: EdgeInsets.zero,
          child: Column(
            children: [
              _SettingRow(
                label: 'Username',
                value: u.username,
                onTap: () => _editSheet(context, ref, _Field.username),
                first: true,
              ),
              const Divider(height: 1, color: C.border),
              _SettingRow(
                label: 'Phone',
                value: u.phone == null ? 'Not set' : fmtPhone(u.phone),
                muted: u.phone == null,
                onTap: () => _editSheet(context, ref, _Field.phone),
              ),
              const Divider(height: 1, color: C.border),
              _SettingRow(
                label: 'Password',
                value: 'Set a new one',
                muted: true,
                onTap: () => _editSheet(context, ref, _Field.password),
                last: true,
              ),
            ],
          ),
        ),
        const _Heading('Access'),
        SrsCard(
          padding: EdgeInsets.zero,
          child: Column(
            children: [
              _ToggleRow(
                leading: Icon(
                  Icons.key_rounded,
                  size: 20,
                  color: u.active ? C.green : C.muted,
                ),
                title: 'Can sign in',
                description: 'Off blocks the app. Orders stay.',
                value: u.active,
                onChanged: (_) => _toggleActive(context, ref),
              ),
              const Divider(height: 1, color: C.border),
              _ResultsRow(
                u: u,
                onAddPhone: () => _editSheet(context, ref, _Field.phone),
              ),
            ],
          ),
        ),
        const SizedBox(height: S.s24),
        BigButton(
          'Delete user',
          outline: true,
          danger: true,
          icon: Icons.delete_outline_rounded,
          onPressed: () => _delete(context, ref),
        ),
        const SizedBox(height: S.s10),
        Center(
          child: Text(
            'Their saved orders are kept.',
            style: ts(12, c: C.muted),
          ),
        ),
      ],
    );
  }

  void _editSheet(BuildContext context, WidgetRef ref, _Field f) {
    showSheet<void>(context, (_) => _EditField(user: u, field: f));
  }

  void _shopsSheet(BuildContext context, WidgetRef ref) {
    showSheet<void>(context, (_) => _ShopsEditor(user: u, shops: shops));
  }
}

class _Profile extends StatelessWidget {
  const _Profile({required this.u});
  final AppUser u;

  @override
  Widget build(BuildContext context) => SrsCard(
    padding: const EdgeInsets.all(S.s20),
    child: Row(
      children: [
        UserAvatar(user: u, size: 68),
        const SizedBox(width: S.s16),
        Expanded(
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Text(
                u.username,
                maxLines: 1,
                overflow: TextOverflow.ellipsis,
                style: ts(24, w: w7, ls: -0.3),
              ),
              const SizedBox(height: S.s8),
              Wrap(
                spacing: S.s10,
                runSpacing: S.s6,
                crossAxisAlignment: WrapCrossAlignment.center,
                children: [
                  StatusLabel(active: u.active),
                  if (u.phone != null)
                    Row(
                      mainAxisSize: MainAxisSize.min,
                      children: [
                        const Icon(
                          Icons.phone_outlined,
                          size: 14,
                          color: C.muted,
                        ),
                        const SizedBox(width: S.s4),
                        Text(fmtPhone(u.phone), style: ts(13, c: C.muted)),
                      ],
                    ),
                ],
              ),
            ],
          ),
        ),
      ],
    ),
  );
}

class _Heading extends StatelessWidget {
  const _Heading(this.text, {this.action, this.onAction});
  final String text;
  final String? action;
  final VoidCallback? onAction;

  @override
  Widget build(BuildContext context) => Padding(
    padding: const EdgeInsets.fromLTRB(S.s2, S.s22, 0, S.s10),
    child: Row(
      children: [
        Expanded(
          child: Text(text, style: ts(17, w: w7)),
        ),
        if (action != null) _LinkButton(action!, onTap: onAction),
      ],
    ),
  );
}

/// A quiet navy text action with a hover pill, for actions inside a section.
class _LinkButton extends StatelessWidget {
  const _LinkButton(this.label, {required this.onTap});
  final String label;
  final VoidCallback? onTap;

  @override
  Widget build(BuildContext context) => Pressable(
    onTap: onTap,
    radius: R.pill,
    builder: (_, hover) => AnimatedContainer(
      duration: const Duration(milliseconds: 140),
      height: 32,
      padding: const EdgeInsets.symmetric(horizontal: S.s12),
      alignment: Alignment.center,
      decoration: BoxDecoration(
        color: hover ? C.chip : Colors.transparent,
        borderRadius: BorderRadius.circular(R.pill),
      ),
      child: Row(
        mainAxisSize: MainAxisSize.min,
        children: [
          const Icon(Icons.edit_outlined, size: 15, color: C.navy),
          const SizedBox(width: S.s6),
          Text(
            label,
            style: ts(13, w: w6, c: C.navy),
          ),
        ],
      ),
    ),
  );
}

/// A setting with an on/off switch: icon, title, an optional short status
/// line, and the switch.
class _ToggleRow extends StatelessWidget {
  const _ToggleRow({
    required this.leading,
    required this.title,
    required this.description,
    required this.value,
    required this.onChanged,
    this.status,
  });
  final Widget leading;

  /// The title, then one short line saying what the setting does.
  final String title, description;
  final Widget? status;
  final bool value;

  /// Null disables the switch.
  final ValueChanged<bool>? onChanged;

  @override
  Widget build(BuildContext context) => Padding(
    padding: const EdgeInsets.fromLTRB(S.s16, S.s12, S.s10, S.s12),
    child: Row(
      children: [
        SizedBox(width: 24, child: Center(child: leading)),
        const SizedBox(width: S.s12),
        Expanded(
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              // The switch carries the name for screen readers.
              ExcludeSemantics(
                child: Text(title, style: ts(15, w: w6)),
              ),
              const SizedBox(height: S.s2),
              Text(description, style: ts(12, c: C.muted, h: 1.35)),
              if (status != null) ...[const SizedBox(height: S.s4), status!],
            ],
          ),
        ),
        const SizedBox(width: S.s8),
        Semantics(
          label: title,
          child: Switch(
            value: value,
            onChanged: onChanged,
            activeTrackColor: C.green,
            activeThumbColor: Colors.white,
          ),
        ),
      ],
    ),
  );
}

/// "WhatsApp results". srs-api sends a summary for the user's shops after
/// each draw, only to active users with a phone number; the status line says
/// where it goes, or why it won't.
class _ResultsRow extends ConsumerStatefulWidget {
  const _ResultsRow({required this.u, required this.onAddPhone});
  final AppUser u;
  final VoidCallback onAddPhone;

  @override
  ConsumerState<_ResultsRow> createState() => _ResultsRowState();
}

class _ResultsRowState extends ConsumerState<_ResultsRow> {
  /// The value being saved, shown until the reloaded user agrees.
  bool? _pending;

  @override
  void didUpdateWidget(_ResultsRow old) {
    super.didUpdateWidget(old);
    if (_pending == widget.u.sendResults) _pending = null;
  }

  Future<void> _set(bool on) async {
    if (_pending != null) return;
    setState(() => _pending = on);
    try {
      await mutate(
        ref,
        () => ref.read(apiProvider).updateUser(widget.u.id, sendResults: on),
      );
      if (mounted) {
        toast(context, on ? 'WhatsApp results on' : 'WhatsApp results off');
      }
    } catch (e) {
      if (!mounted) return;
      setState(() => _pending = null);
      toast(context, errText(e));
    }
  }

  @override
  Widget build(BuildContext context) {
    final u = widget.u;
    final on = _pending ?? u.sendResults;
    final noPhone = u.phone == null;
    final note = ts(12, w: w6, c: C.ink);
    final Widget? status = noPhone
        ? Pressable(
            onTap: widget.onAddPhone,
            radius: R.sm,
            builder: (_, hover) => Text(
              'Add a phone number first',
              style: ts(
                12,
                w: w6,
                c: C.navy,
              ).copyWith(decoration: hover ? TextDecoration.underline : null),
            ),
          )
        : !on
        ? null
        : !u.active
        ? Text('Paused while inactive', style: note)
        : null;
    return _ToggleRow(
      leading: WhatsAppLogo(
        size: 20,
        color: on && !noPhone && u.active ? null : C.muted,
      ),
      title: 'WhatsApp results',
      description: 'Sends results after each draw.',
      status: status,
      value: on,
      // Turning it on needs a phone number; turning it off never does.
      onChanged: _pending != null || (!on && noPhone) ? null : _set,
    );
  }
}

/// A whole-row control: label on top, value below, chevron at the end.
class _SettingRow extends StatelessWidget {
  const _SettingRow({
    required this.label,
    required this.value,
    required this.onTap,
    this.muted = false,
    this.first = false,
    this.last = false,
  });
  final String label, value;
  final VoidCallback onTap;
  final bool muted, first, last;

  @override
  Widget build(BuildContext context) => Pressable(
    onTap: onTap,
    label: 'Change ${label.toLowerCase()}',
    radius: 0,
    builder: (_, hover) => AnimatedContainer(
      duration: const Duration(milliseconds: 120),
      padding: const EdgeInsets.fromLTRB(S.s16, S.s12, S.s12, S.s12),
      decoration: BoxDecoration(
        color: hover ? C.hover : Colors.transparent,
        borderRadius: BorderRadius.vertical(
          top: Radius.circular(first ? R.card : 0),
          bottom: Radius.circular(last ? R.card : 0),
        ),
      ),
      child: Row(
        children: [
          Expanded(
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Text(
                  label,
                  style: ts(12, w: w6, c: C.muted),
                ),
                const SizedBox(height: S.s4),
                Text(
                  value,
                  maxLines: 1,
                  overflow: TextOverflow.ellipsis,
                  style: ts(15, w: w6, c: muted ? C.muted : C.ink),
                ),
              ],
            ),
          ),
          Text(
            'Change',
            style: ts(13, w: w6, c: C.navy),
          ),
          const SizedBox(width: S.s2),
          const Icon(Icons.chevron_right_rounded, color: C.placeholder),
        ],
      ),
    ),
  );
}

enum _Field { username, phone, password }

class _EditField extends ConsumerStatefulWidget {
  const _EditField({required this.user, required this.field});
  final AppUser user;
  final _Field field;

  @override
  ConsumerState<_EditField> createState() => _EditFieldState();
}

class _EditFieldState extends ConsumerState<_EditField> {
  late final _c = TextEditingController(
    text: switch (widget.field) {
      _Field.username => widget.user.username,
      _Field.phone => (widget.user.phone ?? '').replaceFirst(
        RegExp(r'^91'),
        '',
      ),
      _Field.password => '',
    },
  );
  bool _busy = false;
  String? _error;

  @override
  void dispose() {
    _c.dispose();
    super.dispose();
  }

  Future<void> _save() async {
    setState(() {
      _busy = true;
      _error = null;
    });
    final api = ref.read(apiProvider);
    final id = widget.user.id;
    try {
      await mutate(ref, () {
        switch (widget.field) {
          case _Field.username:
            return api.updateUser(id, username: _c.text);
          case _Field.phone:
            return _c.text.trim().isEmpty
                ? api.updateUser(id, clearPhone: true)
                : api.updateUser(id, phone: _c.text);
          case _Field.password:
            return api.updateUser(id, password: _c.text);
        }
      });
      if (!mounted) return;
      Navigator.pop(context);
      toast(context, switch (widget.field) {
        _Field.username => 'Username changed',
        _Field.phone => 'Phone updated',
        _Field.password => 'Password changed',
      });
    } catch (e) {
      if (mounted) setState(() => _error = errText(e));
    } finally {
      if (mounted) setState(() => _busy = false);
    }
  }

  @override
  Widget build(BuildContext context) {
    final f = widget.field;
    final title = switch (f) {
      _Field.username => 'Change username',
      _Field.phone => 'Change phone',
      _Field.password => 'Set new password',
    };
    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Text(title, style: ts(20, w: w7)),
        const SizedBox(height: S.s4),
        Text(
          f == _Field.password
              ? 'Users cannot change their own password. Share the new password with ${widget.user.username}.'
              : 'For ${widget.user.username}',
          style: ts(13, c: C.muted),
        ),
        const SizedBox(height: S.s20),
        SrsField(
          controller: _c,
          autofocus: true,
          label: switch (f) {
            _Field.username => 'Username',
            _Field.phone => 'Phone',
            _Field.password => 'New password',
          },
          hint: f == _Field.phone ? '90000 12345' : null,
          prefix: f == _Field.phone ? '+91  ' : null,
          password: f == _Field.password,
          keyboard: f == _Field.phone ? TextInputType.phone : null,
          formatters: f == _Field.phone
              ? [
                  FilteringTextInputFormatter.allow(RegExp(r'[0-9 ]')),
                  LengthLimitingTextInputFormatter(12),
                ]
              : null,
          helper: f == _Field.password
              ? 'At least 8 characters.'
              : f == _Field.phone
              ? 'Leave blank to remove the phone number.'
              : null,
          onChanged: (_) => setState(() => _error = null),
          onSubmitted: (_) => _save(),
        ),
        if (_error != null) ...[
          const SizedBox(height: S.s12),
          ErrorLine(_error!),
        ],
        const SizedBox(height: S.s20),
        BigButton('Save', loading: _busy, onPressed: _save),
      ],
    );
  }
}

class _ShopsEditor extends ConsumerStatefulWidget {
  const _ShopsEditor({required this.user, required this.shops});
  final AppUser user;
  final List<Shop> shops;

  @override
  ConsumerState<_ShopsEditor> createState() => _ShopsEditorState();
}

class _ShopsEditorState extends ConsumerState<_ShopsEditor> {
  late final Set<int> _sel = widget.user.shopIds.toSet();
  bool _busy = false;
  String? _error;

  Future<void> _save() async {
    setState(() {
      _busy = true;
      _error = null;
    });
    try {
      await mutate(
        ref,
        () => ref.read(apiProvider).setUserShops(widget.user.id, _sel.toList()),
      );
      if (!mounted) return;
      Navigator.pop(context);
      toast(context, 'Shops updated');
    } catch (e) {
      if (mounted) setState(() => _error = errText(e));
    } finally {
      if (mounted) setState(() => _busy = false);
    }
  }

  @override
  Widget build(BuildContext context) {
    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Text('Assigned shops', style: ts(20, w: w7)),
        const SizedBox(height: S.s4),
        Text(
          'This user can only view data for the selected shops.',
          style: ts(13, c: C.muted),
        ),
        const SizedBox(height: S.s18),
        ShopPicker(
          shops: widget.shops,
          selected: _sel,
          onToggle: (id) => setState(
            () => _sel.contains(id) ? _sel.remove(id) : _sel.add(id),
          ),
        ),
        if (_error != null) ...[
          const SizedBox(height: S.s8),
          ErrorLine(_error!),
        ],
        const SizedBox(height: S.s14),
        BigButton('Save', loading: _busy, onPressed: _save),
      ],
    );
  }
}