// editor_session.cpp — the ReaSamplerEditor's session/bridge state: construction, the
// live-bank snapshot (refreshFromBank / rebuildVisible), the sync tick, the
// commit-and-reload seam, selection loading, the loaded capture's marker resolution, and
// the decoded-PCM + peak thumbnail caches. UI thread only; every edit commits off the audio
// thread via the processor's reloadInstrument.

#include "shell/instrument/reasampler_editor.h"

#include <algorithm>
#include <cstdint>
#include <string>
#include <vector>

#include "core/audio/peaks.h"            // computeEnvelope (the cached peak thumbnail)
#include "core/capture/capture_paths.h"  // resolveBankFile (shared path resolution)
#include "core/capture/wav_codec.h"       // parseWavLayout, extractFloatFrames
#include "core/ui/bank_grid.h"           // ThumbnailKey / thumbnailKeyString (the pure key)
#include "core/util/file_bytes.h"        // shared whole-file loader
#include "ext_keys.h"
#include "core/instrument/engine/loop/loop_span.h"  // defaultLoopBounds (the shared ghost span)
#include "core/instrument/ui/browser_scroll.h"  // nameMatchesQuery (type-to-filter)
#include "shell/instrument/reaper_bridge.h"
#include "shell/instrument/reasampler_processor.h"

using namespace Steinberg;

namespace reasampler::vst {

using namespace reasampler::instrument::map;  // sample_map vocabulary (selectSample / listSamples / …)
using audio::computeEnvelope;
using capture::WavLayout;
using capture::extractFloatFrames;
using capture::parseWavLayout;
using capture::resolveBankFile;
using instrument::engine::loop::LoopBounds;
using instrument::engine::loop::defaultLoopBounds;
using instrument::ui::nameMatchesQuery;
using ui::ThumbnailKey;
using ui::thumbnailKeyString;
using util::readFileBytes;

ReaSamplerEditor::ReaSamplerEditor(ReaSamplerProcessor* processor)
    : CPluginView(nullptr), processor_(processor) {
    // The default IS the enforced floor (checkSizeConstraint) — the face opens at the size its
    // band stack is laid out for and can only be grown from there.
    ViewRect r(0, 0, instrument::ui::kEditorMinWidth, instrument::ui::kEditorMinHeight);
    setRect(r);
}

void ReaSamplerEditor::refreshFromBank() {
    // Main/UI thread only — reads the live bank over the bridge (allocates, calls REAPER).
    thumbCache_.clear();  // a bank edit may have re-captured/removed a sample; drop stale peaks
    pcmCache_.clear();    // and its decoded PCM (the waveform + snap source)
    channelPcmId_.clear();
    channelPcm_ = ChannelPcm{};
    if (!processor_) {
        samples_.clear();
        banks_.clear();
        visible_.clear();
        selectedId_.clear();
        params_ = InstrumentParams{};
        return;
    }
    auto banksJson = processor_->bridge().readReasamplerExtState(reasampler::kProjExtBanksKey);
    samples_ = banksJson ? listSamples(*banksJson) : std::vector<SampleChoice>{};
    banks_ = banksJson ? listBanks(*banksJson) : std::vector<BankChoice>{};
    selectedId_ = processor_->selectedSampleId();
    params_ = processor_->instrumentParams();
    channelMode_ = processor_->channelMode();
    voiceCount_ = processor_->voiceCount();
    voiceMode_ = processor_->voiceMode();
    monoTrigger_ = processor_->monoTrigger();
    // A refresh that emptied the selection closes the curve popup — an open-but-invisible
    // modal would otherwise swallow clicks on the empty state.
    if (selectedId_.empty()) closeCurvePopup();
    // Drop a filter that names a bank no longer present.
    if (!activeFilterBankId_.empty()) {
        bool found = false;
        for (const BankChoice& b : banks_) if (b.id == activeFilterBankId_) found = true;
        if (!found) activeFilterBankId_.clear();
    }
    rebuildVisible();
}

void ReaSamplerEditor::rebuildVisible() {
    // Bank filter first, then type-to-filter search narrows by name substring.
    visible_.clear();
    for (const SampleChoice& s : samples_) {
        const bool inBank = activeFilterBankId_.empty() || s.bankId == activeFilterBankId_;
        if (!inBank) continue;
        const std::string& name = s.displayName.empty() ? s.id : s.displayName;
        if (nameMatchesQuery(name, searchQuery_)) visible_.push_back(s);
    }
    // scrollOffset_ is clamped at paint/wheel time (where layout is known); this runs on
    // the sync-timer refresh too, so it must not reset the user's scroll here.
}

#ifdef _WIN32
// Windows-only (the WM_TIMER cadence + invalidate() are the Win32 child-window path).
void ReaSamplerEditor::onSyncTimer() {
    // UI thread (WM_TIMER). Never while a drag is in flight: a reload mid-drag would
    // rebuild the instrument and repaint under the cursor, yanking the edit — the next
    // tick picks up the change after release.
    if (!processor_) return;
    if (drag_ != DragKind::kNone) return;  // defer past the in-flight edit

    // An open editor is the focused assignment target (thundering-herd policy); instances
    // with no editor open never poll (the timer is bound to the child window).
    const ReaSamplerProcessor::BankSyncResult r = processor_->pollBankSync(/*isFocusedTarget=*/true);

    // Re-snapshot only when something changed.
    if (r.reloaded || r.applied) {
        refreshFromBank();
        invalidate();
    }

    // Decay the drop-affordance banner so it auto-dismisses a few ticks after a drop.
    if (dropHintTicks_ > 0) {
        --dropHintTicks_;
        invalidate();
    }
}
#endif  // _WIN32

void ReaSamplerEditor::commitAndReload() {
    // UI thread only. Publishes the edited selection + parameter set, then rebuilds off the
    // audio thread. The reload also copies the loaded capture's file ref + intrinsics into
    // the instance-owned refs table — a browser load is the moment the instance becomes
    // self-contained for that sample.
    if (!processor_) return;
    processor_->setSelectedSampleId(selectedId_);
    processor_->setInstrumentParams(params_);
    processor_->reloadInstrument();
    // The reload may have auto-defaulted the channel mode (implicit only) — re-read so the
    // toggle draws what the engine actually decoded with.
    channelMode_ = processor_->channelMode();
#ifdef _WIN32
    invalidate();
#endif
}

void ReaSamplerEditor::commitLive() {
    // UI thread only. See the declaration for why this still writes the parameter set.
    if (!processor_) return;
    processor_->setInstrumentParams(params_);
    processor_->publishLiveParams();
}

bool ReaSamplerEditor::dragCommitsLive(DragKind kind, int paramId) const {
    // The decision itself is the pure liveCommitFor's; this is only the shell's drag-kind
    // vocabulary mapped onto it, so the routing is pinned by deck_groups' tests rather than
    // by inspection of this file.
    using instrument::ui::LiveDragKind;
    const LiveDragKind k = kind == DragKind::kDeckKnob ? LiveDragKind::kDeckKnob
                         : kind == DragKind::kEnvNode  ? LiveDragKind::kEnvNode
                                                       : LiveDragKind::kOther;
    return instrument::ui::liveCommitFor(k, paramId);
}

void ReaSamplerEditor::closeCurvePopup() {
    curvePopup_ = CurveTarget::kNone;
    if (drag_ == DragKind::kCurveNode) {
        drag_ = DragKind::kNone;
        curvePointIndex_ = -1;
    }
}

void ReaSamplerEditor::loadSelection(const std::string& id) {
    // A load REPLACES the loaded sound. The shaping parameters (play mode, envelopes, pitch
    // engine, key-track, velocity curve) are NOT reset — the one set governs whatever is
    // loaded, so a load swaps the sound and keeps the settings. The three CAPTURE-ANCHORED
    // overrides are: a root, a loop span and a start frame all name positions in the
    // OUTGOING capture and mean nothing in the new one, so they clear and the new capture
    // plays from its own bank intrinsics. The loop crossfade goes with the span it belongs
    // to — it is a length in the outgoing capture's frames.
    selectedId_ = id;
    params_.rootOverride.reset();
    params_.loopOverride.reset();
    params_.loopCrossfadeFrames = 0;
    params_.startPoint.reset();
    commitAndReload();
}

ReaSamplerEditor::SetupMarkers ReaSamplerEditor::pickedMarkers(std::int64_t frames) const {
    SetupMarkers m;
    // Seed from the bank's intrinsic loop (fact about the file), then let the parameter set's
    // override win (the instrument's performance choice). Read the loop intrinsic from the
    // live bank blob (the same path selectSample uses); when that is not readable (extension
    // absent / not yet parsed) the instance-owned ref carries the same intrinsics. Skipped
    // entirely once an override is already set — it would just be overwritten below, and the
    // bridge read + JSON parse it costs is real (mouseDownWaveform's arbitration calls this on
    // every waveform click, not just marker grabs, to know whether a tab or marker candidate
    // hits at all).
    if (processor_ && !params_.loopOverride) {
        std::optional<SelectedSample> sel;
        auto banksJson =
            processor_->bridge().readReasamplerExtState(reasampler::kProjExtBanksKey);
        if (banksJson) sel = selectSample(*banksJson, selectedId_);
        if (!sel) {
            const SampleRefs refs = processor_->sampleRefs();
            if (const SelectedSample* r = findRef(refs, selectedId_)) sel = *r;
        }
        if (sel && sel->loop.hasLoop) {
            m.hasLoop = true;
            m.loopStart = sel->loop.start;
            m.loopEnd = sel->loop.end;
        }
    }
    // The parameter set's override (loop + start) supersedes the intrinsic.
    if (params_.loopOverride) {
        m.hasLoop = params_.loopOverride->hasLoop;
        m.loopStart = params_.loopOverride->start;
        m.loopEnd = params_.loopOverride->end;
    }
    if (params_.startPoint) m.start = *params_.startPoint;
    m.crossfade = params_.loopCrossfadeFrames;
    // A collapsed or inverted span is the OFF state (the engine refuses it either way), so
    // park the handles on the shared default rather than leaving them stacked on each other
    // where neither could be grabbed apart again. The markers are still drawn at 'no loop'
    // weight — drag one to CREATE a loop.
    if (!m.hasLoop || m.loopEnd <= m.loopStart) {
        m.hasLoop = false;
        const LoopBounds d = defaultLoopBounds(frames);
        m.loopStart = d.start;
        m.loopEnd = d.end;
    }
    return m;
}

void ReaSamplerEditor::applyMarkers(const SetupMarkers& m) {
    // Write the edited markers into the parameter set as the loop/start override. The bank
    // intrinsic is never written (read-only bank consumer).
    SampleLoop loop;
    // Collapsing the span onto itself is the OFF gesture — record it as such so the next
    // pickedMarkers re-offers the default handles instead of two coincident ones.
    loop.hasLoop = m.hasLoop && m.loopEnd > m.loopStart;
    loop.start = m.loopStart;
    loop.end = m.loopEnd;
    params_.loopOverride = loop;
    // OFF parks the crossfade at 0 too — loadSelection's own clear (a fresh capture has no
    // loop to fade) is the same rule; leaving a stale length here would silently re-apply it
    // (clamped) the next time a loop is dragged back in.
    params_.loopCrossfadeFrames = loop.hasLoop ? m.crossfade : 0;
    params_.startPoint = m.start;
}

int ReaSamplerEditor::effectiveRoot() const {
    if (params_.rootOverride) return *params_.rootOverride;
    for (const SampleChoice& s : samples_) {
        if (s.id == selectedId_ && s.rootNote) return *s.rootNote;
    }
    return 60;
}

std::string ReaSamplerEditor::samplePathFor(const std::string& sampleId) const {
    // SampleChoice is the browser's metadata projection and does not carry the WAV path, so
    // resolve it from the live bank blob (selectSample).
    if (!processor_) return {};
    auto banksJson = processor_->bridge().readReasamplerExtState(reasampler::kProjExtBanksKey);
    if (banksJson) {
        // An empty relativePath (found the entry, but it carries no path) falls through to
        // the refs fallback below rather than short-circuiting on it.
        if (auto sel = selectSample(*banksJson, sampleId); sel && !sel->relativePath.empty()) {
            return sel->relativePath;
        }
    }
    // Fallback: the bank blob is not readable (extension absent / not yet parsed) or the id
    // went stale there — the instance-owned ref still carries the path, so a self-contained
    // instance draws its loaded sound's waveform regardless.
    const SampleRefs refs = processor_->sampleRefs();
    if (const SelectedSample* r = findRef(refs, sampleId)) return r->relativePath;
    return {};
}

const ReaSamplerEditor::ChannelPcm& ReaSamplerEditor::channelPcmFor(
    const std::string& sampleId) {
    if (channelPcmId_ == sampleId) return channelPcm_;

    // A failed decode is still cached (channelCount stays 0) so a broken/missing file is not
    // re-read on every paint.
    channelPcmId_ = sampleId;
    channelPcm_ = ChannelPcm{};
    const std::string relativePath = samplePathFor(sampleId);
    if (relativePath.empty()) return channelPcm_;

    const std::string projectDir = processor_->bridge().activeProjectDir();
    const std::vector<std::uint8_t> bytes =
        readFileBytes(resolveBankFile(projectDir, relativePath));  // empty on any failure
    const WavLayout layout = parseWavLayout(bytes);
    if (layout.valid) {
        channelPcm_.interleaved = extractFloatFrames(bytes, layout, 0, layout.frameCount());
        channelPcm_.channelCount = static_cast<int>(layout.channelCount);
    }
    return channelPcm_;
}

const std::vector<AudioSample>& ReaSamplerEditor::monoPcmFor(const std::string& sampleId) {
    auto it = pcmCache_.find(sampleId);
    if (it != pcmCache_.end()) return it->second;

    // Every failure path caches an empty vector so a broken/missing file is not re-decoded on
    // every paint. Keyed by id (width-independent) — the thumbnail bins this at whatever
    // width, the snap scans it directly.
    std::vector<AudioSample> mono;
    const std::string relativePath = samplePathFor(sampleId);
    if (!relativePath.empty()) {
        const std::string projectDir = processor_->bridge().activeProjectDir();
        const std::string abs = resolveBankFile(projectDir, relativePath);
        const std::vector<std::uint8_t> bytes = readFileBytes(abs);  // empty on any failure
        const WavLayout layout = parseWavLayout(bytes);
        if (layout.valid) {
            std::vector<AudioSample> interleaved =
                extractFloatFrames(bytes, layout, 0, layout.frameCount());
            mono = downmixToMono(interleaved, layout.channelCount);
        }
    }
    auto ins = pcmCache_.emplace(sampleId, std::move(mono));
    return ins.first->second;
}

const Envelope& ReaSamplerEditor::thumbnailFor(const std::string& sampleId, int binCount) {
    // Key through the pure ThumbnailKey (bank_grid, length-prefixed id — collision-proof) so
    // both thumbnail pipelines share one tested key grammar. The editor invalidates by
    // wholesale clear() on refresh/resize, so the bank generation carries no information here.
    const std::string key =
        thumbnailKeyString(ThumbnailKey{sampleId, binCount, /*generation=*/0});
    auto it = thumbCache_.find(key);
    if (it != thumbCache_.end()) return it->second;

    // Bin the (cached) decoded mono PCM at the requested width — one decode per id, reused by
    // every thumbnail width AND the waveform surface + snap.
    const std::vector<AudioSample>& mono = monoPcmFor(sampleId);
    Envelope env;
    if (!mono.empty()) {
        // Clamp bins to the frame count: computeEnvelope pads binCount > frameCount with
        // trailing empty {0,0} bins, which would render a very short sample as a comb of
        // spikes over flat gaps.
        const std::size_t bins =
            (std::min)(static_cast<std::size_t>((std::max)(1, binCount)), mono.size());
        env = computeEnvelope(mono, 1, mono.size(), bins);
    }
    auto ins = thumbCache_.emplace(key, std::move(env));
    return ins.first->second;
}

ReaSamplerEditor::~ReaSamplerEditor() {
#ifdef _WIN32
    if (childHwnd_) {
        DestroyWindow(childHwnd_);
        childHwnd_ = nullptr;
    }
#endif
}

}  // namespace reasampler::vst