import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:lucide_icons_flutter/lucide_icons.dart';

import '../tokens.dart';
import 'cards.dart';

/// Labelled field.
///
/// White with a hairline at rest, and on focus the edge goes crimson with a
/// 3pt wash ring around it. The ring is the whole reason this is a container
/// rather than an `InputDecoration`: it is a spread shadow in the brand's
/// lightest tint, which no `InputBorder` can draw, and it is what makes the
/// focused field read as lit rather than merely outlined.
///
/// [optional] appends the grey marker that keeps skippable destination and
/// recipient fields honestly signposted.
class DmTextField extends StatefulWidget {
  const DmTextField({
    super.key,
    this.label,
    required this.controller,
    this.hint,
    this.optional = false,
    this.keyboardType,
    this.maxLength,
    this.maxLines = 1,
    this.prefix,
    this.textInputAction,
    this.onSubmitted,
    this.autofocus = false,
    this.digitsOnly = false,
    this.mono = false,
    this.obscure = false,
    this.onClear,
    this.floating = false,
  });

  /// The caption above the field, or null for a field that stands alone.
  ///
  /// Nullable because a screen whose heading already says what to type does
  /// not need to say it again directly underneath — "Enter your mobile number"
  /// above a field captioned "Phone number" is one sentence printed twice.
  final String? label;
  final TextEditingController controller;
  final String? hint;
  final bool optional;

  /// Masks what is typed. For a PIN, which is a credential a customer may be
  /// entering with somebody stood next to them — and which, unlike a posted
  /// OTP, they will keep using.
  final bool obscure;
  final TextInputType? keyboardType;
  final int? maxLength;
  final int maxLines;
  final String? prefix;
  final TextInputAction? textInputAction;
  final ValueChanged<String>? onSubmitted;
  final bool autofocus;
  final bool digitsOnly;

  /// Sets the value in mono — a pincode or a phone number, where the customer
  /// checks the digits back.
  final bool mono;

  /// Shows a clear button on the right when non-null.
  final VoidCallback? onClear;

  /// Puts [label] inside the field while it is empty, and floats it above once
  /// there is something to caption.
  ///
  /// An empty field under its own caption is two rows to ask one question, and
  /// on a screen with two of them that is four rows of chrome around two
  /// slabs of white. Floating, the question sits where the answer will go — so
  /// the field is never blank and the caption only appears when it has a job,
  /// which is reminding the customer what they already typed.
  final bool floating;

  @override
  State<DmTextField> createState() => _DmTextFieldState();
}

class _DmTextFieldState extends State<DmTextField> {
  final FocusNode _node = FocusNode();

  @override
  void initState() {
    super.initState();
    _node.addListener(() => setState(() {}));
    if (widget.floating) {
      widget.controller.addListener(_onText);
    }
  }

  void _onText() => setState(() {});

  @override
  void dispose() {
    if (widget.floating) widget.controller.removeListener(_onText);
    _node.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    final focused = _node.hasFocus;

    // A floating label is above the field only once it has a reason to be:
    // something typed, or a cursor in it.
    final lifted = !widget.floating ||
        focused ||
        widget.controller.text.isNotEmpty;
    final textStyle = widget.mono
        ? DmText.monoLg.copyWith(fontSize: 15.5, color: DmColors.ink)
        : DmText.field;

    return Padding(
      padding: const EdgeInsets.only(bottom: 14),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          if (widget.label != null)
            AnimatedSize(
              duration: DmMotion.fast,
              curve: DmMotion.ease,
              alignment: Alignment.bottomLeft,
              child: !lifted
                  ? const SizedBox(width: double.infinity)
                  : Padding(
                      padding: const EdgeInsets.only(bottom: 8),
                      child: Text.rich(
                        TextSpan(
                          style: DmText.label,
                          children: [
                            TextSpan(text: widget.label),
                            if (widget.optional)
                              const TextSpan(
                                text: '   Optional',
                                style: TextStyle(
                                  color: DmColors.ink4,
                                  fontWeight: FontWeight.w500,
                                ),
                              ),
                          ],
                        ),
                      ),
                    ),
            ),
          AnimatedContainer(
            duration: DmMotion.fast,
            curve: DmMotion.ease,
            constraints: BoxConstraints(
              minHeight: widget.maxLines > 1 ? 0 : DmSpace.field,
            ),
            decoration: BoxDecoration(
              color: DmColors.surface,
              borderRadius: DmRadius.all(DmRadius.sm),
              border: Border.all(
                color: focused ? DmColors.brand : DmColors.border,
              ),
              boxShadow: focused
                  ? const [
                      BoxShadow(
                        color: DmColors.brandSoft,
                        spreadRadius: 3,
                        blurRadius: 0,
                      ),
                    ]
                  : null,
            ),
            child: Row(
              crossAxisAlignment: widget.maxLines > 1
                  ? CrossAxisAlignment.start
                  : CrossAxisAlignment.center,
              children: [
                if (widget.prefix != null) ...[
                  Padding(
                    padding: const EdgeInsets.fromLTRB(15, 0, 12, 0),
                    child: Text(
                      widget.prefix!,
                      style: DmText.field.copyWith(
                        color: DmColors.ink2,
                        fontWeight: FontWeight.w700,
                      ),
                    ),
                  ),
                  // A hairline between the country code and the number: they
                  // are two different things and reading them as one string is
                  // how a digit gets lost.
                  Container(width: 1, height: 22, color: DmColors.border),
                ],
                Expanded(
                  child: TextField(
                    controller: widget.controller,
                    focusNode: _node,
                    obscureText: widget.obscure,
                    // Masked fields default to a dot the mono face does not
                    // carry, which renders as a box. A bullet is in every
                    // family the app bundles.
                    obscuringCharacter: '•',
                    keyboardType: widget.keyboardType,
                    maxLines: widget.maxLines,
                    autofocus: widget.autofocus,
                    textInputAction: widget.textInputAction,
                    onSubmitted: widget.onSubmitted,
                    cursorColor: DmColors.brand,
                    cursorRadius: const Radius.circular(2),
                    style: textStyle,
                    inputFormatters: [
                      if (widget.maxLength != null)
                        LengthLimitingTextInputFormatter(widget.maxLength),
                      if (widget.digitsOnly)
                        FilteringTextInputFormatter.digitsOnly,
                    ],
                    decoration: InputDecoration(
                      isDense: true,
                      // While the label is down inside the field it IS the
                      // placeholder; [hint] only gets the slot once the label
                      // has floated out of it.
                      hintText: lifted
                          ? widget.hint
                          : (widget.label ?? widget.hint),
                      hintStyle: DmText.field.copyWith(
                        color: DmColors.ink3,
                        fontWeight: FontWeight.w500,
                      ),
                      filled: false,
                      counterText: '',
                      contentPadding: EdgeInsets.fromLTRB(
                        widget.prefix == null ? 15 : 12,
                        widget.maxLines > 1 ? 15 : 14,
                        8,
                        widget.maxLines > 1 ? 15 : 14,
                      ),
                      border: InputBorder.none,
                      enabledBorder: InputBorder.none,
                      focusedBorder: InputBorder.none,
                    ),
                  ),
                ),
                if (widget.onClear != null)
                  Padding(
                    padding: const EdgeInsets.only(right: 6),
                    child: InkWell(
                      onTap: widget.onClear,
                      borderRadius: DmRadius.all(DmRadius.xs),
                      child: const SizedBox(
                        width: 34,
                        height: 34,
                        child: Icon(LucideIcons.x, size: 17, color: DmColors.ink3),
                      ),
                    ),
                  ),
              ],
            ),
          ),
        ],
      ),
    );
  }
}

/// A settings row: label left, value or control right.
class DmRow extends StatelessWidget {
  const DmRow({
    super.key,
    required this.label,
    this.value,
    this.trailing,
    this.onTap,
    this.showChevron = false,
    this.icon,
    this.note,
  });

  final String label;
  final String? value;
  final Widget? trailing;
  final VoidCallback? onTap;
  final bool showChevron;

  /// The row's leading glyph. Account's rows all carry one, so the list can be
  /// scanned by shape before it is read.
  ///
  /// It used to sit in a washed crimson tile. Four of those down a settings
  /// list put four brand-coloured blocks on the quietest screen in the app,
  /// and each one cost 56pt of the width the row's value needed — which is why
  /// "38 Mettupalayam Road" rendered as "38 Mettupal…". The glyph alone scans
  /// just as well.
  final IconData? icon;

  /// The line under the label — "3 locations configured", "Real-time SMS &
  /// Push". It is what turns a menu into a list of states the customer can
  /// check without opening anything, which is most of what a settings screen
  /// is for.
  final String? note;

  @override
  Widget build(BuildContext context) {
    return Material(
      color: Colors.transparent,
      child: InkWell(
        onTap: onTap,
        splashColor: DmColors.brandSoft,
        highlightColor: DmColors.brandSoft.withValues(alpha: 0.5),
        child: Container(
          constraints: const BoxConstraints(minHeight: 58),
          padding: const EdgeInsets.fromLTRB(18, 13, 18, 13),
          child: Row(
            children: [
              if (icon != null) ...[
                // A glyph in a well, not a glyph. Six bare strokes down a
                // settings list read as a column of marks; six wells read as
                // six rows, and the well is what gives the label a left edge
                // to sit against.
                Container(
                  width: 36,
                  height: 36,
                  alignment: Alignment.center,
                  decoration: BoxDecoration(
                    color: DmColors.surfaceAlt,
                    borderRadius: DmRadius.all(DmRadius.xs),
                  ),
                  child: Icon(icon, size: 17, color: DmColors.ink2),
                ),
                const SizedBox(width: 13),
              ],
              // The label is what the row IS and it is never the thing that
              // truncates. Two rounds of flex arithmetic here produced
              // "Payment metho…" and "38 Mettupal…" in turn; the fix was not a
              // third ratio, it was to stop passing values that cannot fit.
              // A [value] is a word — "UPI", "SMS and push" — and anything
              // longer belongs on the screen the row opens.
              Expanded(
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  mainAxisSize: MainAxisSize.min,
                  children: [
                    Text(
                      label,
                      style: DmText.cardTitle.copyWith(fontSize: 15.5),
                      maxLines: 1,
                      overflow: TextOverflow.ellipsis,
                    ),
                    if (note != null)
                      Text(
                        note!,
                        style: DmText.small.copyWith(
                          fontSize: 12.5,
                          color: DmColors.ink3,
                        ),
                        maxLines: 1,
                        overflow: TextOverflow.ellipsis,
                      ),
                  ],
                ),
              ),
              if (value != null) ...[
                const SizedBox(width: 12),
                Text(
                  value!,
                  style: DmText.value,
                  textAlign: TextAlign.right,
                  maxLines: 1,
                ),
              ],
              ?trailing,
              if (showChevron) ...[
                const SizedBox(width: 8),
                const Icon(
                  LucideIcons.chevronRight,
                  size: 18,
                  color: DmColors.ink4,
                ),
              ],
            ],
          ),
        ),
      ),
    );
  }
}

/// A run of [DmRow]s on one surface.
///
/// ── Card → rules → card ──
///
/// It was a bordered card, then bare ruled rows on the canvas. The bare rows
/// were right about the border — three decorations were doing one job — and
/// wrong about the surface: with nothing under them Account read as a text
/// file, while every other list in the app had come back onto a card.
///
/// It is a [DmCard] again, which now separates by lift rather than by edge.
/// The rules stay, because they belong to the card and are what let one
/// [DmRow] work alone or in a stack of five.
class DmRowGroup extends StatelessWidget {
  const DmRowGroup({super.key, required this.children});

  final List<Widget> children;

  @override
  Widget build(BuildContext context) => DmCard(children: children);
}

/// Switch in brand colours.
class DmSwitch extends StatelessWidget {
  const DmSwitch({super.key, required this.value, required this.onChanged});

  final bool value;
  final ValueChanged<bool> onChanged;

  @override
  Widget build(BuildContext context) {
    return Switch.adaptive(
      value: value,
      onChanged: (v) {
        HapticFeedback.selectionClick();
        onChanged(v);
      },
      activeThumbColor: Colors.white,
      activeTrackColor: DmColors.brand,
      inactiveThumbColor: Colors.white,
      inactiveTrackColor: DmColors.border,
      trackOutlineColor: WidgetStateProperty.all(Colors.transparent),
    );
  }
}

/// The search field used by every picker sheet.
///
/// It was written inline inside the pickup sheet and then wanted again by the
/// destination sheet, which is the moment a style becomes a component. Filled
/// white on the canvas rather than outlined: a search field that is the only
/// control above a list does not need an edge to be found, and the fill is what
/// makes it read as a place to type rather than as the first row of the list.
class DmSearchField extends StatelessWidget {
  const DmSearchField({
    super.key,
    required this.controller,
    required this.hint,
    this.onChanged,
    this.autofocus = false,
  });

  final TextEditingController controller;
  final String hint;
  final ValueChanged<String>? onChanged;
  final bool autofocus;

  @override
  Widget build(BuildContext context) {
    return TextField(
      controller: controller,
      onChanged: onChanged,
      autofocus: autofocus,
      cursorColor: DmColors.brand,
      style: DmText.field,
      textInputAction: TextInputAction.search,
      decoration: InputDecoration(
        hintText: hint,
        hintStyle: DmText.field.copyWith(
          color: DmColors.ink3,
          fontWeight: FontWeight.w500,
        ),
        prefixIcon: const Icon(
          LucideIcons.search,
          size: 20,
          color: DmColors.ink3,
        ),
        filled: true,
        fillColor: DmColors.surface,
        contentPadding: const EdgeInsets.symmetric(
          horizontal: 16,
          vertical: 14,
        ),
        border: _border(DmColors.border, 1),
        enabledBorder: _border(DmColors.border, 1),
        focusedBorder: _border(DmColors.brand, 1.5),
      ),
    );
  }

  static OutlineInputBorder _border(Color color, double width) =>
      OutlineInputBorder(
        borderRadius: DmRadius.all(DmRadius.sm),
        borderSide: BorderSide(color: color, width: width),
      );
}