//              Copyright Catch2 Authors
// Distributed under the Boost Software License, Version 1.0.
//   (See accompanying file LICENSE.txt or copy at
//        https://www.boost.org/LICENSE_1_0.txt)

// SPDX-License-Identifier: BSL-1.0
#ifndef CATCH_TEST_CASE_TRACKER_HPP_INCLUDED
#define CATCH_TEST_CASE_TRACKER_HPP_INCLUDED

#include <catch2/internal/catch_source_line_info.hpp>
#include <catch2/internal/catch_unique_ptr.hpp>
#include <catch2/internal/catch_stringref.hpp>

#include <string>
#include <vector>

namespace Catch {
namespace TestCaseTracking {

    struct NameAndLocation {
        std::string name;
        SourceLineInfo location;

        NameAndLocation( std::string&& _name, SourceLineInfo const& _location );
        friend bool operator==(NameAndLocation const& lhs, NameAndLocation const& rhs) {
            // This is a very cheap check that should have a very high hit rate.
            // If we get to SourceLineInfo::operator==, we will redo it, but the
            // cost of repeating is trivial at that point (we will be paying
            // multiple strcmp/memcmps at that point).
            if ( lhs.location.line != rhs.location.line ) { return false; }
            return lhs.name == rhs.name && lhs.location == rhs.location;
        }
        friend bool operator!=(NameAndLocation const& lhs,
                               NameAndLocation const& rhs) {
            return !( lhs == rhs );
        }
    };

    /**
     * This is a variant of `NameAndLocation` that does not own the name string
     *
     * This avoids extra allocations when trying to locate a tracker by its
     * name and location, as long as we make sure that trackers only keep
     * around the owning variant.
     */
    struct NameAndLocationRef {
        StringRef name;
        SourceLineInfo location;

        constexpr NameAndLocationRef( StringRef name_,
                                      SourceLineInfo location_ ):
            name( name_ ), location( location_ ) {}

        friend bool operator==( NameAndLocation const& lhs,
                                NameAndLocationRef const& rhs ) {
            // This is a very cheap check that should have a very high hit rate.
            // If we get to SourceLineInfo::operator==, we will redo it, but the
            // cost of repeating is trivial at that point (we will be paying
            // multiple strcmp/memcmps at that point).
            if ( lhs.location.line != rhs.location.line ) { return false; }
            return StringRef( lhs.name ) == rhs.name &&
                   lhs.location == rhs.location;
        }
        friend bool operator==( NameAndLocationRef const& lhs,
                                NameAndLocation const& rhs ) {
            return rhs == lhs;
        }
    };

    class ITracker;

    using ITrackerPtr = Catch::Detail::unique_ptr<ITracker>;

    class ITracker {
        NameAndLocation m_nameAndLocation;

        using Children = std::vector<ITrackerPtr>;

    protected:
        enum CycleState {
            NotStarted,
            Executing,
            ExecutingChildren,
            NeedsAnotherRun,
            CompletedSuccessfully,
            Failed
        };

        ITracker* m_parent = nullptr;
        Children m_children;
        CycleState m_runState = NotStarted;

    public:
        ITracker( NameAndLocation&& nameAndLoc, ITracker* parent ):
            m_nameAndLocation( CATCH_MOVE(nameAndLoc) ),
            m_parent( parent )
        {}


        // static queries
        NameAndLocation const& nameAndLocation() const {
            return m_nameAndLocation;
        }
        ITracker* parent() const {
            return m_parent;
        }

        virtual ~ITracker(); // = default


        // dynamic queries

        //! Returns true if tracker run to completion (successfully or not)
        virtual bool isComplete() const = 0;
        //! Returns true if tracker run to completion successfully
        bool isSuccessfullyCompleted() const {
            return m_runState == CompletedSuccessfully;
        }
        //! Returns true if tracker has started but hasn't been completed
        bool isOpen() const;
        //! Returns true iff tracker has started
        bool hasStarted() const;

        // actions
        virtual void close() = 0; // Successfully complete
        virtual void fail() = 0;
        void markAsNeedingAnotherRun();

        //! Register a nested ITracker
        void addChild( ITrackerPtr&& child );
        /**
         * Returns ptr to specific child if register with this tracker.
         *
         * Returns nullptr if not found.
         */
        ITracker* findChild( NameAndLocationRef const& nameAndLocation );
        //! Have any children been added?
        bool hasChildren() const {
            return !m_children.empty();
        }


        //! Marks tracker as executing a child, doing se recursively up the tree
        void openChild();

        /**
         * Returns true if the instance is a section tracker
         *
         * Subclasses should override to true if they are, replaces RTTI
         * for internal debug checks.
         */
        virtual bool isSectionTracker() const;
        /**
         * Returns true if the instance is a generator tracker
         *
         * Subclasses should override to true if they are, replaces RTTI
         * for internal debug checks.
         */
        virtual bool isGeneratorTracker() const;
    };

    class TrackerContext {

        enum RunState {
            NotStarted,
            Executing,
            CompletedCycle
        };

        ITrackerPtr m_rootTracker;
        ITracker* m_currentTracker = nullptr;
        RunState m_runState = NotStarted;

    public:

        ITracker& startRun();

        void startCycle() {
            m_currentTracker = m_rootTracker.get();
            m_runState = Executing;
        }
        void completeCycle();

        bool completedCycle() const;
        ITracker& currentTracker() { return *m_currentTracker; }
        void setCurrentTracker( ITracker* tracker );
    };

    class TrackerBase : public ITracker {
    protected:

        TrackerContext& m_ctx;

    public:
        TrackerBase( NameAndLocation&& nameAndLocation, TrackerContext& ctx, ITracker* parent );

        bool isComplete() const override;

        void open();

        void close() override;
        void fail() override;

    private:
        void moveToParent();
        void moveToThis();
    };

    class SectionTracker : public TrackerBase {
        std::vector<StringRef> m_filters;
        // Note that lifetime-wise we piggy back off the name stored in the `ITracker` parent`.
        // Currently it allocates owns the name, so this is safe. If it is later refactored
        // to not own the name, the name still has to outlive the `ITracker` parent, so
        // this should still be safe.
        StringRef m_trimmed_name;
    public:
        SectionTracker( NameAndLocation&& nameAndLocation, TrackerContext& ctx, ITracker* parent );

        bool isSectionTracker() const override;

        bool isComplete() const override;

        static SectionTracker& acquire( TrackerContext& ctx, NameAndLocationRef const& nameAndLocation );

        void tryOpen();

        void addInitialFilters( std::vector<std::string> const& filters );
        void addNextFilters( std::vector<StringRef> const& filters );
        //! Returns filters active in this tracker
        std::vector<StringRef> const& getFilters() const { return m_filters; }
        //! Returns whitespace-trimmed name of the tracked section
        StringRef trimmedName() const;
    };

} // namespace TestCaseTracking

using TestCaseTracking::ITracker;
using TestCaseTracking::TrackerContext;
using TestCaseTracking::SectionTracker;

} // namespace Catch

#endif // CATCH_TEST_CASE_TRACKER_HPP_INCLUDED