import 'package:flutter/material.dart';

import '../tokens.dart';

/// How loudly a card speaks.
enum DmCardTone {
  /// White on the canvas, hairline edge. Almost everything.
  plain,

  /// Filled crimson. **One per screen, at most** — it is the screen's answer
  /// to "what is happening right now": the live ETA, the booked confirmation,
  /// the delivered summary. A second one on the same screen and neither wins.
  fill,

  /// A crimson wash. Supporting brand information that must not shout: the
  /// address being collected from, the rider on the way, a reassurance.
  wash,

  /// The canvas itself, edged. For content that is deliberately inert — the
  /// build panel on Account.
  sunken,
}

/// A panel that stacks rows and rules them apart.
///
/// The rule between rows belongs to the card, not to the rows: a row does not
/// know whether it is first, and a card that is handed one child draws no rule
/// at all, so the same [DmCardCell] works alone or in a stack of five.
///
/// ── Edge → shadow (2026-09-23) ──
///
/// This was a bordered panel, which was the right correction to the shadowed
/// card it replaced — that one dropped a shadow under everything, so nothing
/// on a screen could be said to matter more than anything else. Eight hairline
/// boxes down a screen turned out to have the same failure in reverse: the
/// outline became the loudest thing about an object whose job is to be quiet.
///
/// A card is lifted now, not outlined. [DmShadow.card] is two very soft layers
/// — an ambient wash and a short contact shadow — neither of which is legible
/// *as* a shadow; together they read as the white being nearer than the canvas.
/// [raised] doubles them for the one card on a screen that needs acting on.
class DmCard extends StatelessWidget {
  const DmCard({
    super.key,
    required this.children,
    this.tone = DmCardTone.plain,
    this.rail = false,
    this.raised = false,
    this.onTap,
  });

  final List<Widget> children;
  final DmCardTone tone;

  /// Deeper lift, for the one card in a list that is live or needs a decision.
  final bool raised;

  /// A 3pt crimson spine down the leading edge — marks the one row in a list
  /// that needs the customer's attention now.
  final bool rail;

  final VoidCallback? onTap;

  Color get _background => switch (tone) {
        DmCardTone.plain => DmColors.surface,
        DmCardTone.fill => DmColors.brand,
        DmCardTone.wash => DmColors.brandSoft,
        // Not the canvas any more: the page is white, and a card filled with
        // the page colour is not sunken, it is invisible.
        DmCardTone.sunken => DmColors.surfaceAlt,
      };

  Color get _edge => switch (tone) {
        DmCardTone.plain => DmColors.border,
        DmCardTone.fill => DmColors.brand,
        DmCardTone.wash => DmColors.brandLine,
        DmCardTone.sunken => DmColors.border,
      };

  /// The rule between two rows of the same card. On crimson it is a lightened
  /// white rather than a darker line: a dark rule on a saturated field reads as
  /// a crack, a light one as a seam.
  /// Only the white card lifts. See the note in [build].
  bool get _lifts => tone == DmCardTone.plain;

  Color get _rule => switch (tone) {
        DmCardTone.plain => DmColors.hairline,
        DmCardTone.fill => const Color(0x2EFFFFFF),
        DmCardTone.wash => DmColors.brandLine,
        DmCardTone.sunken => DmColors.border,
      };

  @override
  Widget build(BuildContext context) {
    // The edge is drawn in the FOREGROUND, over the children.
    //
    // As a background border it was painted first and then covered: a cell with
    // its own tint — the washed status strip at the head of an order card, the
    // crimson rows on the booked screen — filled the whole box, border included,
    // and the card lost its outline exactly where it needed one most. A
    // foreground decoration paints last, so every cell is clipped inside an
    // edge that is always visible.
    final radius = DmRadius.all(DmRadius.card);
    final card = DecoratedBox(
      decoration: BoxDecoration(
        color: _background,
        borderRadius: radius,
        boxShadow: _lifts ? (raised ? DmShadow.cardRaised : DmShadow.card) : null,
      ),
      child: Container(
        // ── Every card keeps its edge now ──
        //
        // A white card used to have none: the warm canvas underneath was doing
        // the separating, and a border on top of that contrast read as an
        // outlined box rather than a lifted surface.
        //
        // The page is white. A white card on it is invisible — measured, not
        // guessed: a scan across a card boundary on the Orders golden was
        // #FFFFFF from end to end, with the shadow contributing nothing the
        // eye could find. One of the two has to do the separating, and with
        // the page white it has to be the edge.
        //
        // The lift stays underneath it. Border plus a soft shadow is the iOS
        // and Revolut shape; it is not the borderless Airbnb one, and that is
        // the cost of a white page.
        foregroundDecoration: BoxDecoration(
          borderRadius: radius,
          border: Border.all(color: _edge),
        ),
        child: ClipRRect(
          borderRadius: radius,
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.stretch,
            mainAxisSize: MainAxisSize.min,
            children: [
              for (var i = 0; i < children.length; i++) ...[
                if (i > 0) Container(height: 1, color: _rule),
                children[i],
              ],
            ],
          ),
        ),
      ),
    );

    final railed = rail
        ? Container(
            decoration: BoxDecoration(
              color: DmColors.brand,
              borderRadius: radius,
              boxShadow: _lifts ? DmShadow.cardRaised : null,
            ),
            padding: const EdgeInsets.only(left: 3),
            child: card,
          )
        : card;

    if (onTap == null) return railed;
    return Semantics(
      button: true,
      child: GestureDetector(
        behavior: HitTestBehavior.opaque,
        onTap: onTap,
        child: railed,
      ),
    );
  }
}

/// One padded cell inside a [DmCard] — the design's `.p`.
class DmCardCell extends StatelessWidget {
  const DmCardCell({
    super.key,
    required this.child,
    this.padding = const EdgeInsets.fromLTRB(16, 15, 16, 15),
    this.background,
    this.onTap,
  });

  final Widget child;
  final EdgeInsets padding;

  /// Tints this cell alone — a wash strip at the head of a plain card.
  final Color? background;

  final VoidCallback? onTap;

  @override
  Widget build(BuildContext context) {
    final body = Padding(padding: padding, child: child);
    final painted = background == null
        ? body
        : ColoredBox(color: background!, child: body);

    if (onTap == null) return painted;
    return Material(
      color: background ?? Colors.transparent,
      child: InkWell(
        onTap: onTap,
        splashColor: DmColors.brandSoft,
        highlightColor: DmColors.brandSoft.withValues(alpha: 0.6),
        child: body,
      ),
    );
  }
}

/// The common cell: a glyph or tile, a title with an optional second line, and
/// something on the right — a value, a chevron, an inline action.
class DmCardRow extends StatelessWidget {
  const DmCardRow({
    super.key,
    required this.title,
    this.eyebrow,
    this.subtitle,
    this.leading,
    this.trailing,
    this.tone = DmCardTone.plain,
    this.onTap,
    this.titleStyle,
    this.subtitleStyle,
    this.background,
    this.crossAlign = CrossAxisAlignment.center,
  });

  final String title;

  /// A micro-label above the title — "COLLECTING FROM".
  final String? eyebrow;
  final String? subtitle;
  final Widget? leading;
  final Widget? trailing;

  /// The tone of the *card this row sits in*, so the row can pick text colours
  /// that survive a crimson field.
  final DmCardTone tone;

  final VoidCallback? onTap;
  final TextStyle? titleStyle;
  final TextStyle? subtitleStyle;
  final Color? background;
  final CrossAxisAlignment crossAlign;

  @override
  Widget build(BuildContext context) {
    final onFill = tone == DmCardTone.fill;
    final titleColor = onFill ? Colors.white : DmColors.ink;
    final subColor = switch (tone) {
      DmCardTone.fill => DmColors.onBrand2,
      DmCardTone.wash => DmColors.brandPress,
      _ => DmColors.ink2,
    };
    final eyebrowColor = switch (tone) {
      DmCardTone.fill => DmColors.onBrand3,
      DmCardTone.wash => DmColors.brand,
      _ => DmColors.ink3,
    };

    return DmCardCell(
      background: background,
      onTap: onTap,
      child: Row(
        crossAxisAlignment: crossAlign,
        children: [
          if (leading != null) ...[leading!, const SizedBox(width: 12)],
          Expanded(
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              mainAxisSize: MainAxisSize.min,
              children: [
                if (eyebrow != null) ...[
                  Text(
                    eyebrow!.toUpperCase(),
                    style: DmText.eyebrow.copyWith(color: eyebrowColor),
                  ),
                  const SizedBox(height: 3),
                ],
                Text(
                  title,
                  style: (titleStyle ?? DmText.cardTitle).copyWith(
                    color: titleStyle?.color ?? titleColor,
                  ),
                ),
                if (subtitle != null) ...[
                  const SizedBox(height: 3),
                  Text(
                    subtitle!,
                    style: (subtitleStyle ?? DmText.small).copyWith(
                      color: subtitleStyle?.color ?? subColor,
                    ),
                  ),
                ],
              ],
            ),
          ),
          if (trailing != null) ...[const SizedBox(width: 12), trailing!],
        ],
      ),
    );
  }
}

/// How a [DmTile] is filled.
enum DmTileTone { sunken, wash, brand, onFill }

/// The 38pt rounded square that holds a glyph or a step number.
///
/// Square, not a circle: the cards, fields and buttons around it are all cut
/// with the same small radius, and a disc in the middle of that is the one
/// shape that has to be explained.
class DmTile extends StatelessWidget {
  const DmTile({
    super.key,
    this.icon,
    this.label,
    this.tone = DmTileTone.sunken,
    this.size = 38,
  }) : assert(icon != null || label != null, 'a tile shows a glyph or a number');

  final IconData? icon;

  /// A step number, for the "how it works" sequence.
  final String? label;
  final DmTileTone tone;
  final double size;

  @override
  Widget build(BuildContext context) {
    final (bg, fg) = switch (tone) {
      DmTileTone.sunken => (DmColors.surfaceAlt, DmColors.ink),
      DmTileTone.wash => (DmColors.brandSoft, DmColors.brand),
      DmTileTone.brand => (DmColors.brand, Colors.white),
      DmTileTone.onFill => (DmColors.onBrandRaise, Colors.white),
    };

    return Container(
      width: size,
      height: size,
      alignment: Alignment.center,
      decoration: BoxDecoration(
        color: bg,
        borderRadius: DmRadius.all(DmRadius.xs),
      ),
      child: icon != null
          ? Icon(icon, size: size * 0.47, color: fg)
          : Text(
              label!,
              style: DmText.label.copyWith(
                fontSize: 12.5,
                fontWeight: FontWeight.w800,
                fontVariations: const [FontVariation('wght', 800)],
                color: fg,
              ),
            ),
    );
  }
}

/// A figure and its caption, sat in its own bordered box. Used in pairs.
class DmMetric extends StatelessWidget {
  const DmMetric({
    super.key,
    required this.figure,
    required this.caption,
    this.tone = DmCardTone.plain,
  });

  final String figure;
  final String caption;
  final DmCardTone tone;

  @override
  Widget build(BuildContext context) {
    final (bg, edge, figureColor, captionColor) = switch (tone) {
      DmCardTone.fill => (
          DmColors.brand,
          DmColors.brand,
          Colors.white,
          DmColors.onBrand3,
        ),
      DmCardTone.wash => (
          DmColors.brandSoft,
          DmColors.brandLine,
          DmColors.brand,
          DmColors.brandPress,
        ),
      _ => (DmColors.surface, DmColors.border, DmColors.ink, DmColors.ink3),
    };

    return Container(
      padding: const EdgeInsets.fromLTRB(15, 14, 15, 14),
      decoration: BoxDecoration(
        color: bg,
        border: Border.all(color: edge),
        borderRadius: DmRadius.all(DmRadius.md),
      ),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        mainAxisSize: MainAxisSize.min,
        children: [
          Text(
            figure,
            style: DmText.display.copyWith(fontSize: 25, height: 1, color: figureColor),
          ),
          const SizedBox(height: 5),
          Text(
            caption,
            style: DmText.value.copyWith(fontSize: 12.5, color: captionColor),
          ),
        ],
      ),
    );
  }
}

/// A label and its figure on one baseline — the fare breakdown, the build
/// panel. The label may wrap; the figure never does.
class DmFareLine extends StatelessWidget {
  const DmFareLine({
    super.key,
    required this.label,
    required this.value,
    this.strong = false,
    this.mono = true,
  });

  final String label;
  final String value;

  /// The total, rather than one of the lines that make it up.
  final bool strong;

  /// Figures are mono by default — they are meant to be compared down a column.
  final bool mono;

  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: const EdgeInsets.symmetric(vertical: 5),
      child: Row(
        crossAxisAlignment: CrossAxisAlignment.baseline,
        textBaseline: TextBaseline.alphabetic,
        children: [
          Expanded(
            child: Text(
              label,
              style: DmText.small.copyWith(
                fontWeight: strong ? FontWeight.w600 : FontWeight.w500,
              ),
            ),
          ),
          const SizedBox(width: 12),
          Text(
            value,
            maxLines: 1,
            style: mono
                ? DmText.mono.copyWith(
                    fontSize: strong ? 15 : 13.5,
                    color: strong ? DmColors.brand : DmColors.ink,
                  )
                : DmText.value.copyWith(
                    color: strong ? DmColors.brand : DmColors.ink,
                  ),
          ),
        ],
      ),
    );
  }
}

/// The uppercase micro-label that heads a group of cards.
class DmMicroHead extends StatelessWidget {
  const DmMicroHead(
    this.text, {
    super.key,
    this.brand = true,
    this.top = 20,
    this.bottom = 10,
    this.trailing,
  });

  final String text;

  /// Crimson heads brand content; neutral heads everything else.
  final bool brand;
  final double top;
  final double bottom;
  final Widget? trailing;

  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: EdgeInsets.only(top: top, bottom: bottom),
      child: Row(
        children: [
          Expanded(
            child: Text(
              text.toUpperCase(),
              style: DmText.eyebrow.copyWith(
                color: brand ? DmColors.brand : DmColors.ink3,
              ),
            ),
          ),
          ?trailing,
        ],
      ),
    );
  }
}