#pragma once
// mode_switch — the REAPER-free layout math behind the bank_panel's Design-View
// mode switch (Phase D, Wave 4 — D5). A segmented control `[ Arrange | Design ]`
// (N-mode general, one segment per registered mode) drawn in a fixed-height header
// strip at the top of the docked panel. The panel shell (bank_panel.cpp) owns the
// SWELL window, LICE drawing, and the live ViewModeModel read + mode activation —
// all REAPER-bound, DAW-verified. What is NOT DAW-bound — how N segments tile a
// header rectangle, and which segment a click lands in — lives here so it is
// unit-tested outside the DAW (CLAUDE.md §load-bearing split). Mirror of bank_grid.
//
// PURE MODULE: NO REAPER types, NO SWELL, NO vendor/ includes. Standard library
// only. Builds and unit-tests without REAPER.

#include <vector>

namespace reasampler {

// The header strip the switch is drawn into, top-left origin (SWELL/LICE
// convention). (x, y) is the top-left corner; width/height are the strip extents.
// The panel reserves this at the top of its client area and offsets the grid below.
struct HeaderRect {
    int x = 0;
    int y = 0;
    int width = 0;
    int height = 0;

    bool operator==(const HeaderRect& o) const {
        return x == o.x && y == o.y && width == o.width && height == o.height;
    }
};

// One segment's pixel rectangle within the header, top-left origin. These are the
// draw bounds for one mode's button; the panel draws the mode's display name inside
// it and lights it when it is the active mode.
struct SegmentRect {
    int x = 0;
    int y = 0;
    int width = 0;
    int height = 0;

    bool operator==(const SegmentRect& o) const {
        return x == o.x && y == o.y && width == o.width && height == o.height;
    }
};

// Divides `header` into `segmentCount` equal segments left-to-right, in the caller's
// order (the panel passes modes in ordinal order). Returns exactly segmentCount
// rects. The division tiles the header EXACTLY: each segment's left edge is
// header.x + (i * width) / segmentCount, so integer rounding is absorbed at the
// boundaries — segments abut with no gap and no overlap, and the last segment
// reaches header.x + header.width precisely (individual widths may differ by one
// pixel when width does not divide evenly). Each segment inherits the header's full
// y/height. segmentCount <= 0 or a non-positive header width returns empty.
std::vector<SegmentRect> computeSegmentRects(const HeaderRect& header,
                                             int segmentCount);

// Hit-tests a point (SWELL/LICE top-left client coords) against the segmented
// control laid out in `header` with `segmentCount` segments. Returns the index of
// the segment containing the point, or -1 for a miss: a point outside the header
// bounds entirely (including below it, where the grid lives), or when segmentCount
// <= 0. Half-open bounds [x, x+width) x [y, y+height) match computeSegmentRects, so
// adjacent segments never both claim a pixel and the point maps to the same segment
// the panel drew there.
int hitTestSegment(int px, int py, const HeaderRect& header, int segmentCount);

} // namespace reasampler