/*
 * Copyright 2024 Google LLC
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#ifndef skgpu_graphite_task_DrawTask_DEFINED
#define skgpu_graphite_task_DrawTask_DEFINED

#include "include/core/SkRefCnt.h"
#include "src/gpu/graphite/ScratchResourceManager.h"
#include "src/gpu/graphite/task/Task.h"
#include "src/gpu/graphite/task/TaskList.h"

#include <functional>
#include <utility>

namespace skgpu::graphite {

class CommandBuffer;
class Context;
class GraphicsPipeline;
class ResourceProvider;
class RuntimeEffectDictionary;

/**
 * DrawTask is a collection of subtasks that are executed in order to produce some intended
 * image in the DrawTask's target. As such, at least one of its subtasks will either be a
 * RenderPassTask, ComputeTask or CopyXToTextureTask that directly modify the target.
*/
class DrawTask final : public Task, private ScratchResourceManager::PendingUseListener {
public:
    explicit DrawTask(sk_sp<TextureProxy> target);
    ~DrawTask() override;

    Status prepareResources(ResourceProvider*,
                            ScratchResourceManager*,
                            sk_sp<const RuntimeEffectDictionary>) override;

    Status addCommands(Context*, CommandBuffer*, ReplayTargetData) override;

    bool visitPipelines(const std::function<bool(const GraphicsPipeline*)>& visitor) override {
        return fChildTasks.visitPipelines(visitor);
    }

    bool visitProxies(const std::function<bool(const TextureProxy*)>& visitor) override {
        return fChildTasks.visitProxies(visitor);
    }

private:
    friend class DrawContext; // for "addTask"

    // DrawTask is modified directly by DrawContext for efficiency, but its task list will be
    // fixed once DrawContext snaps the task.
    void addTask(sk_sp<Task> task) { fChildTasks.add(std::move(task)); }
    bool hasTasks() const { return fChildTasks.hasTasks(); }

    void onUseCompleted(ScratchResourceManager*) override;

    sk_sp<TextureProxy> fTarget;
    TaskList fChildTasks;

    // Once there is one DrawTask for a scratch device, whether or not the target is instantaited
    // will be equivalent to whether or not prepareResources() has been called already if the task
    // is referenced multiple times in a Recording. Right now, however, a scratch device can still
    // produce several DrawTasks (in which case they will see an instantiated proxy so should still
    // prepare their own resources instead of discarding themselves).
    bool fPrepared = false;

#if defined(SK_DUMP_TASKS)
    void dump(int index, const char* prefix) const override {
        if (index >= 0) {
            SkDebugf("%s%d: Draw Task (target=%p)\n", prefix, index, fTarget.get());
        } else {
            SkDebugf("%sDraw Task (target=%p)\n", prefix, fTarget.get());
        }

        std::string childPrefix = prefix;
        SkASSERT((strlen(prefix) & 3) == 0);
        static constexpr uint32_t kPrefixIncrement = 4;
        if (strlen(prefix) >= kPrefixIncrement) {
            const char* lastBranch = prefix + strlen(prefix) - kPrefixIncrement;
            if (strcmp(lastBranch, "│   ") == 0) {
                childPrefix.replace(strlen(prefix) - kPrefixIncrement, kPrefixIncrement, "│   ");
            } else if (strcmp(lastBranch, "└── ") == 0) {
                childPrefix.replace(strlen(prefix) - kPrefixIncrement, kPrefixIncrement, "    ");
            }
        }

        fChildTasks.visit([&](const Task* task, bool isLast) {
            task->dump(-1, (childPrefix + (isLast ? "└── " : "│   ")).c_str());
        });
    }
#endif
};

} // namespace skgpu::graphite

#endif // skgpu_graphite_task_DrawTask_DEFINED