// embed_strip.h — PURE layout + hit-test for the S6 embedded TCP/MCP strip. NO VST3,
// NO REAPER, NO SWELL/LICE types at the boundary. The mirror of editor_geometry /
// mode_switch: the fiddly rectangle math for the compact inline keymap/level strip lives
// here so it is unit-tested outside the DAW, while the embed shell (reasampler_embed.cpp)
// marshals REAPER's embed messages (paint bitmap + mouse coords) into these functions.
//
// The strip is a single compact band REAPER draws inline in the track/mixer control panel
// (context TCP or MCP) via the Cockos embedded-UI surface. It shows:
//   * the zone layout — each performance zone as a horizontal segment across the keyboard
//     span (MIDI 0..127 mapped to the strip width), so the keymap reads at a glance; and
//   * a thin level band at the bottom — a 0..1 activity indicator the shell fills.
// Interaction is zone SELECTION at most (S6 constraint: no new editing semantics) — a
// click maps to the zone whose key range covers that point, or -1.
//
// It reuses the same Rect + contains() as editor_geometry (the strip and the editor share
// one geometry idiom), so this header depends on editor_geometry.h rather than redefining
// a second rectangle type.

#pragma once

#include "editor_geometry.h"  // Rect, contains — one shared geometry idiom

namespace reasampler::vst {

// The full MIDI key span the strip maps across its width. 128 keys (0..127); the strip's
// horizontal axis is this range, so a zone [lowNote, highNote] becomes a sub-rectangle.
inline constexpr int kEmbedKeyCount = 128;

// Fixed metrics for the strip, exposed so the shell and tests agree.
inline constexpr int kEmbedLevelBandHeight = 4;  // the bottom activity band (px)
inline constexpr int kEmbedKeymapMinHeight = 6;  // keymap area collapses no smaller

// One zone rendered on the strip: its inclusive MIDI key range. This is the minimal
// projection of a PerformanceZone the strip needs (it does not carry sample ids or PCM —
// the shell resolves labels; the strip only lays out ranges). lowNote/highNote are
// expected in [0,127] with low <= high, but the layout clamps defensively so a malformed
// zone never yields an out-of-strip rect.
struct EmbedZone {
    int lowNote = 0;
    int highNote = 127;
};

// The strip's regions, derived from the (w x h) embed area REAPER reports. Both clamp to
// the area so a degenerate (tiny) size never yields a region spilling outside the surface.
struct EmbedLayout {
    Rect keymap;      // top: the zone-segment band (the compact keymap)
    Rect levelBand;   // bottom: the thin level/activity indicator
};

// Divide a (w x h) embed area into the strip's regions. Pure: same inputs -> same layout.
// The level band takes a fixed height at the bottom (clamped so it never exceeds the area
// or starves the keymap below kEmbedKeymapMinHeight); the keymap takes the rest. A zero or
// negative size yields empty rects (no inversion).
EmbedLayout layoutEmbed(int w, int h);

// The horizontal sub-rectangle of the keymap band for a zone spanning [lowNote, highNote]
// (inclusive). The 128-key span maps linearly across keymap.width(); the returned rect
// spans the half-open pixel range [x(lowNote), x(highNote+1)) so adjacent zones (e.g.
// 0..59 and 60..127) tile without a gap or overlap. Notes are clamped to [0,127] and low
// is clamped to <= high, so a malformed zone yields an in-band (possibly zero-width) rect,
// never an inverted one. Pure.
Rect zoneSegmentRect(const EmbedLayout& layout, int lowNote, int highNote);

// The zone a click at (x, y) lands on, given the zones in draw order, or -1 for a click
// outside the keymap band or on a key not covered by any zone. When zones overlap on a
// key, the FIRST covering zone in order wins — mirroring the sampler core's first-match
// Keymap::resolve and the editor's zone order, so selection agrees with playback. Pure.
int zoneAtPoint(const EmbedLayout& layout, const EmbedZone* zones, int zoneCount, int x,
                int y);

// The filled portion of the level band for a 0..1 level. Clamps level to [0,1]; the
// returned rect is the left sub-rectangle of levelBand whose width is level * band width
// (rounded down). level <= 0 -> empty rect; level >= 1 -> the whole band. Pure.
Rect levelFillRect(const EmbedLayout& layout, double level);

}  // namespace reasampler::vst