#include "Windowing/System/EditorWindowSynchronizationPlanner.h"

#include "Windowing/System/EditorWindowPresentationPolicy.h"

#include <XCEditor/Workspace/UIEditorWorkspaceLayoutPersistence.h>

#include <algorithm>

namespace XCEngine::UI::Editor::App {

namespace {

const EditorWindowHostSnapshot* FindHostWindowSnapshot(
    const std::vector<EditorWindowHostSnapshot>& hostWindows,
    std::string_view windowId) {
    const auto it = std::find_if(
        hostWindows.begin(),
        hostWindows.end(),
        [windowId](const EditorWindowHostSnapshot& snapshot) {
            return snapshot.windowId == windowId;
        });
    return it != hostWindows.end() ? &(*it) : nullptr;
}

bool AreWindowWorkspaceStatesEquivalent(
    const UIEditorWindowWorkspaceState& lhs,
    const UIEditorWindowWorkspaceState& rhs) {
    if (lhs.windowId != rhs.windowId) {
        return false;
    }

    return AreUIEditorWorkspaceLayoutSnapshotsEquivalent(
        BuildUIEditorWorkspaceLayoutSnapshot(lhs.workspace, lhs.session),
        BuildUIEditorWorkspaceLayoutSnapshot(rhs.workspace, rhs.session));
}

} // namespace

EditorWindowSynchronizationPlan EditorWindowSynchronizationPlanner::Build(
    const EditorWindowSynchronizationPlannerInput& input) {
    EditorWindowSynchronizationPlan plan = {};

    if (input.panelRegistry == nullptr) {
        plan.errorMessage = "window synchronization planner missing panel registry";
        return plan;
    }
    if (input.targetWindowSet == nullptr) {
        plan.errorMessage = "window synchronization planner missing target window set";
        return plan;
    }

    plan.valid = true;
    plan.targetWindowSet = *input.targetWindowSet;
    plan.actions.reserve(
        input.targetWindowSet->windows.size() + input.hostWindows.size());

    for (const UIEditorWindowWorkspaceState& targetWindowState :
         input.targetWindowSet->windows) {
        const bool primary = targetWindowState.windowId ==
            input.targetWindowSet->primaryWindowId;
        const std::wstring title = ResolveEditorWindowPresentationTitle(
            input.primaryWindowTitle,
            *input.panelRegistry,
            targetWindowState,
            primary);

        const EditorWindowHostSnapshot* const existingSnapshot =
            FindHostWindowSnapshot(input.hostWindows, targetWindowState.windowId);
        if (existingSnapshot == nullptr) {
            EditorWindowSynchronizationAction action = {};
            action.kind = EditorWindowSynchronizationActionKind::CreateWorkspaceWindow;
            action.create.windowState = targetWindowState;
            action.create.primary = primary;
            action.create.title = title;
            if (!input.preferredNewWindowId.empty() &&
                targetWindowState.windowId == input.preferredNewWindowId) {
                action.create.placement = input.preferredPlacement;
            }
            plan.actions.push_back(std::move(action));
            continue;
        }

        if (!existingSnapshot->workspaceWindow) {
            plan.valid = false;
            plan.errorMessage =
                "workspace synchronization rejected: window '" +
                targetWindowState.windowId + "' is not a workspace window";
            plan.actions.clear();
            return plan;
        }

        if (!existingSnapshot->running) {
            plan.valid = false;
            plan.errorMessage =
                "workspace synchronization rejected: window '" +
                targetWindowState.windowId + "' is not running";
            plan.actions.clear();
            return plan;
        }

        const bool needsUpdate =
            !existingSnapshot->hasWorkspaceProjection ||
            !AreWindowWorkspaceStatesEquivalent(
                existingSnapshot->workspaceState,
                targetWindowState) ||
            existingSnapshot->primary != primary ||
            existingSnapshot->title != title;
        if (!needsUpdate) {
            continue;
        }

        EditorWindowSynchronizationAction action = {};
        action.kind = EditorWindowSynchronizationActionKind::UpdateWorkspaceWindow;
        action.update.windowState = targetWindowState;
        action.update.primary = primary;
        action.update.title = title;
        plan.actions.push_back(std::move(action));
    }

    for (const EditorWindowHostSnapshot& snapshot : input.hostWindows) {
        if (!snapshot.workspaceWindow ||
            !snapshot.hasNativeWindow ||
            !snapshot.running ||
            snapshot.primary) {
            continue;
        }

        const bool existsInTarget =
            FindUIEditorWindowWorkspaceState(*input.targetWindowSet, snapshot.windowId) != nullptr;
        if (existsInTarget) {
            continue;
        }

        EditorWindowSynchronizationAction action = {};
        action.kind = EditorWindowSynchronizationActionKind::CloseWorkspaceWindow;
        action.close.windowId = snapshot.windowId;
        plan.actions.push_back(std::move(action));
    }

    return plan;
}

} // namespace XCEngine::UI::Editor::App