// Copyright 2019 Google LLC.

#ifndef Metrics_DEFINED

#define Metrics_DEFINED

#include <map>

#include "modules/skparagraph/include/TextStyle.h"

namespace skia {

namespace textlayout {

class StyleMetrics {

public:

    StyleMetrics(const TextStyle* style) : text_style(style) {}

    StyleMetrics(const TextStyle* style, SkFontMetrics& metrics)

            : text_style(style), font_metrics(metrics) {}

    const TextStyle* text_style;

    // SkFontMetrics contains the following metrics:

    //

    // * Top                 distance to reserve above baseline

    // * Ascent              distance to reserve below baseline

    // * Descent             extent below baseline

    // * Bottom              extent below baseline

    // * Leading             distance to add between lines

    // * AvgCharWidth        average character width

    // * MaxCharWidth        maximum character width

    // * XMin                minimum x

    // * XMax                maximum x

    // * XHeight             height of lower-case 'x'

    // * CapHeight           height of an upper-case letter

    // * UnderlineThickness  underline thickness

    // * UnderlinePosition   underline position relative to baseline

    // * StrikeoutThickness  strikeout thickness

    // * StrikeoutPosition   strikeout position relative to baseline

    SkFontMetrics font_metrics;

};

class LineMetrics {

public:

    LineMetrics() { }

    LineMetrics(size_t start,

                size_t end,

                size_t end_excluding_whitespace,

                size_t end_including_newline,

                bool hard_break)

            : fStartIndex(start)

            , fEndIndex(end)

            , fEndExcludingWhitespaces(end_excluding_whitespace)

            , fEndIncludingNewline(end_including_newline)

            , fHardBreak(hard_break) {}

    // The following fields are used in the layout process itself.

    // The indexes in the text buffer the line begins and ends.

    size_t fStartIndex = 0;

    size_t fEndIndex = 0;

    size_t fEndExcludingWhitespaces = 0;

    size_t fEndIncludingNewline = 0;

    bool fHardBreak = false;

    // The following fields are tracked after or during layout to provide to

    // the user as well as for computing bounding boxes.

    // The final computed ascent and descent for the line. This can be impacted by

    // the strut, height, scaling, as well as outlying runs that are very tall.

    //

    // The top edge is `baseline - ascent` and the bottom edge is `baseline +

    // descent`. Ascent and descent are provided as positive numbers. Raw numbers

    // for specific runs of text can be obtained in run_metrics_map. These values

    // are the cumulative metrics for the entire line.

    double fAscent = SK_ScalarMax;

    double fDescent = SK_ScalarMin;

    double fUnscaledAscent = SK_ScalarMax;

    // Total height of the paragraph including the current line.

    //

    // The height of the current line is `round(ascent + descent)`.

    double fHeight = 0.0;

    // Width of the line.

    double fWidth = 0.0;

    // The left edge of the line. The right edge can be obtained with `left +

    // width`

    double fLeft = 0.0;

    // The y position of the baseline for this line from the top of the paragraph.

    double fBaseline = 0.0;

    // Zero indexed line number

    size_t fLineNumber = 0;

    // Mapping between text index ranges and the FontMetrics associated with

    // them. The first run will be keyed under start_index. The metrics here

    // are before layout and are the base values we calculate from.

    std::map<size_t, StyleMetrics> fLineMetrics;

};

}  // namespace textlayout

}  // namespace skia

#endif  // Metrics_DEFINED