import "package:flutter/widgets.dart";

import "field_error.dart";
import "overlay.dart" show Tooltip;
import "surface.dart" show Divider;
import "theme/garage_theme.dart";

/// A list of label / field pairs, ruled between entries.
///
/// The other way of showing a set of values is [PropertiesSection], which puts
/// them in a bordered, collapsible card. That card is a subject - a thing with
/// a name and a state you can fold away - and a page made of nothing but those
/// reads as a stack of boxes rather than a set of settings, which is the
/// complaint that produced this.
///
/// Here theres no box and no header. Just rows with a hairline between them,
/// so what you see is the values and where one ends and the next begins.
///
/// Not a scroller: it takes its height from its rows and expects a pane to do
/// the scrolling, the same as a run of sections does.
class SettingsList extends StatelessWidget {
  const SettingsList({super.key, required this.children});

  /// [SettingsRow]s, usually. Anything else is laid out and ruled the same.
  final List<Widget> children;

  @override
  Widget build(BuildContext context) {
    final theme = GarageTheme.of(context);
    final scheme = theme.colorScheme;

    final inset = theme.density.gapSm;

    return Column(
      crossAxisAlignment: CrossAxisAlignment.stretch,
      mainAxisSize: MainAxisSize.min,
      children: [
        for (var i = 0; i < children.length; i++) ...[
          // BETWEEN entries, not around them. A rule above the first row or
          // under the last one draws a box, which is the thing this exists to
          // not be.
          //
          // And the rule runs WIDER than the rows: the inset is on the rows,
          // not on the list, so the line reaches slightly past the text at
          // both ends. A rule that stops exactly where its content stops
          // reads as the edge of a box; one that overshoots reads as a
          // divider between two things.
          if (i > 0) Divider(color: scheme.divider),
          Padding(
            padding: EdgeInsets.symmetric(horizontal: inset),
            child: children[i],
          ),
        ],
      ],
    );
  }
}

/// One label and one field, on a line.
class SettingsRow extends StatelessWidget {
  const SettingsRow({
    super.key,
    required this.label,
    required this.field,
    this.subtitle,
    this.description,
    this.error,
    this.action,
    this.labelTooltip,
  });

  /// Left, and it gets whatever width the field doesnt want.
  final String label;

  /// Shown on hovering the label, and only the label.
  ///
  /// For the exact thing the label is a friendly name for - a permission
  /// string, an id, a unit. That belongs somewhere you can go and look for
  /// it rather than in the row, where it would be a second piece of text
  /// competing with the one a person actually reads.
  ///
  /// It wraps the label text itself, not its half of the row, so the empty
  /// space beside a short label doesnt trigger anything.
  final WidgetBuilder? labelTooltip;

  /// A second line under the label, for the words the label had to leave out.
  ///
  /// A QUALIFIER, not an explanation - "Account, passkeys and sign-in
  /// activity" under "Read", not a sentence about what reading means. If it
  /// needs a sentence it isnt a settings row.
  final String? subtitle;

  /// A full width line UNDER the whole row, label and field both.
  ///
  /// For copy about the setting rather than about the field - consequences,
  /// caveats, what changes when you change it. [subtitle] is a qualifier and
  /// has to fit beside a value; this is a paragraph and doesnt.
  ///
  /// The same slot [PropertyRow] has, for the same reason: a sentence squashed
  /// into the label column is a sentence nobody reads.
  final String? description;

  /// Why the value was refused, under the row and in the destructive colour.
  ///
  /// It also reddens the field's outline, through [FieldErrorScope] - so the
  /// row says which one and this says why, which is the pair a toast cant be:
  /// a message that floats over the corner of the screen has left the field
  /// it was about behind.
  final String? error;

  /// Beside the label, on its line. The onboarding flow's ProductField has the
  /// same slot and puts a muted "Optional" in it; a settings row gets one so
  /// "Required" doesnt have to be found out by pressing Save.
  ///
  /// Styled here rather than by the caller: it reads at the subtitle's size
  /// and colour, so its a tag ON the label rather than a second label. A
  /// caller that sets its own style still wins - this only supplies the
  /// default.
  final Widget? action;

  /// Right, at its own size.
  ///
  /// It is NOT stretched to a column: a Select that says "Engineering" should
  /// be as wide as "Engineering", and a text box thats meant to be wide can
  /// say so with a SizedBox. Stretching everything to one split is what makes
  /// a form of mixed controls look like a table with a ragged edge.
  final Widget field;

  @override
  Widget build(BuildContext context) {
    final theme = GarageTheme.of(context);
    final density = theme.density;

    // textXs over textXxs - the pairing density calls a "label column" in so
    // many words, and the one the consent screen reads right at.
    //
    // The label was inheriting the ambient body size, which is the CONTROL
    // font. Against a textXxs subtitle thats 1.0 to 0.875, near enough the
    // same text twice, and the label stopped reading as the name of anything.
    // A step up puts it at 1.1 to 0.875 and the two lines have different jobs
    // again.
    final labelStyle = theme.typography.normal.copyWith(
      fontSize: density.textXs,
      color: theme.colorScheme.foreground,
    );

    Widget labelText = Text(label, style: labelStyle);
    if (labelTooltip case final tip?) {
      labelText = Tooltip(tooltip: tip, child: labelText);
    }

    final aside = action;
    if (aside != null) {
      labelText = Row(
        mainAxisSize: MainAxisSize.min,
        crossAxisAlignment: CrossAxisAlignment.center,
        children: [
          // flexible, so a long label ellipsises rather than shoving the tag
          // off the end of the column
          Flexible(child: labelText),
          SizedBox(width: density.gapXs),
          DefaultTextStyle.merge(
            style: TextStyle(
              fontSize: density.textXxs,
              color: theme.colorScheme.mutedForeground,
              fontWeight: FontWeight.normal,
            ),
            child: aside,
          ),
        ],
      );
    }

    final row = Padding(
      padding: EdgeInsets.only(
        top: density.gapMd,
        bottom: description == null && error == null
            ? density.gapMd
            : density.gapSm,
      ),
      child: ConstrainedBox(
        // A MINIMUM, and its the height of a row that HAS a subtitle.
        //
        // Otherwise a list where only some rows carry a second line comes out
        // ragged - the plain ones close up to a single line box and the run
        // of rows has two rhythms in it. labelColumnHeight is that stack
        // exactly (textXs over textXxs on the font's own line box), plus the
        // gap this row puts between the two.
        //
        // Rows that are legitimately taller - a four line text box - grow
        // past it untouched, which a fixed height would squash.
        constraints: BoxConstraints(
          minHeight: density.labelColumnHeight + density.gapXxs,
        ),
        child: Row(
          crossAxisAlignment: CrossAxisAlignment.center,
          children: [
            Expanded(
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                mainAxisSize: MainAxisSize.min,
                children: [
                  labelText,
                  if (subtitle != null) ...[
                    // the two lines were touching. A caption sat hard against
                    // the thing it captions reads as a wrapped second line of
                    // it rather than as a note under it.
                    SizedBox(height: density.gapXxs),
                    Text(
                      subtitle!,
                      style: TextStyle(
                        fontSize: density.textXxs,
                        color: theme.colorScheme.mutedForeground,
                      ),
                    ),
                  ],
                ],
              ),
            ),
            SizedBox(width: density.gapMd),
            // Flexible, loose - so the field is BOUNDED but still sizes itself.
            //
            // A bare child in a Row is measured with an unbounded main axis,
            // and anything with a flex child inside it - a ButtonGroup with
            // `fill`, a Row of Expanded - asserts the moment it sees that. As a
            // loose Flexible it gets "at most whats left", so a Text or a Select
            // still shrink wraps and a filled control has a width to divide.
            //
            // Aligned right INSIDE that slot, because the slot is a share of the
            // row rather than the width of the field. Without this a select that
            // wants 90px sits at the left edge of its half and lands in the
            // middle of the line, which is neither one column nor the other.
            Flexible(
              child: Align(
                alignment: Alignment.centerRight,
                child: FieldErrorScope(invalid: error != null, child: field),
              ),
            ),
          ],
        ),
      ),
    );

    final note = description;
    final complaint = error;

    // AnimatedSize even with nothing under the row: a complaint ARRIVING is
    // the interesting case, and a row that only starts animating once it has
    // something to animate would jump on the way in and ease on the way out.
    //
    // Its the row's own height thats moving, so it grows downward - anchored
    // at the top, or every row above the one that was rejected shuffles.
    //
    // And ALWAYS the column under it, even when theres nothing in it but the
    // row. Swapping between `row` and `Column(row, ...)` puts a different
    // widget type at that position, so Flutter throws the subtree away and
    // builds a new one - which takes the FIELD'S element with it. A brand
    // new AnimatedOpacity starts AT its target, so the outline turned up
    // already red however long it had been told to take getting there.
    return AnimatedSize(
      duration: kFieldErrorDuration,
      curve: kFieldErrorCurve,
      alignment: Alignment.topCenter,
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.stretch,
        mainAxisSize: MainAxisSize.min,
        children: [
          row,
          // sat in the row's own bottom padding rather than under it, so the
          // note belongs to the row above it and not to the rule below. Nudged
          // up by the same amount it stands off the next one.
          if (complaint != null)
            Padding(
              padding: EdgeInsets.only(
                bottom: note == null ? density.gapMd : 0,
              ),
              child: Text(
                complaint,
                style: TextStyle(
                  fontSize: density.textXxs,
                  color: theme.colorScheme.destructive,
                ),
              ),
            ),
          if (note != null)
            Padding(
              padding: EdgeInsets.only(
                top: complaint == null ? 0 : density.gapXxs,
                bottom: density.gapMd,
              ),
              child: Text(
                note,
                style: TextStyle(
                  fontSize: density.textXxs,
                  color: theme.colorScheme.mutedForeground,
                ),
              ),
            ),
        ],
      ),
    );
  }
}