// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using System.Runtime.CompilerServices;

namespace System.Runtime.InteropServices.JavaScript
{
    public partial struct JSMarshalerArgument
    {
        /// <summary>
        /// Implementation of the argument marshaling.
        /// It's used by JSImport code generator and should not be used by developers in source code.
        /// </summary>
        /// <param name="value">The value to be marshaled.</param>
#if !DEBUG
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
#endif
        public void ToManaged(out JSObject? value)
        {
            if (slot.Type == MarshalerType.None)
            {
                value = null;
                return;
            }
            var ctx = ToManagedContext;
            value = ctx.CreateCSOwnedProxy(slot.JSHandle);
        }

        /// <summary>
        /// Implementation of the argument marshaling.
        /// It's used by JSImport code generator and should not be used by developers in source code.
        /// </summary>
        /// <param name="value">The value to be marshaled.</param>
#if !DEBUG
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
#endif
        public void ToJS(JSObject? value)
        {
            if (value == null)
            {
                slot.Type = MarshalerType.None;
                // Note: when null JSObject is passed as argument, it can't be used to capture the target thread in JSProxyContext.CapturedInstance
                // in case there is no other argument to capture it from, the call will be dispatched according to JSProxyContext.Default
            }
            else
            {
                value.AssertNotDisposed();
#if FEATURE_WASM_MANAGED_THREADS
                var ctx = value.ProxyContext;

                if (JSProxyContext.CapturingState == JSProxyContext.JSImportOperationState.JSImportParams)
                {
                    JSProxyContext.CaptureContextFromParameter(ctx);
                    slot.ContextHandle = ctx.ContextHandle;
                }
                else if (slot.ContextHandle != ctx.ContextHandle)
                {
                    Environment.FailFast($"ContextHandle mismatch, ManagedThreadId: {Environment.CurrentManagedThreadId}. {Environment.NewLine} {Environment.StackTrace}");
                }
#endif
                slot.Type = MarshalerType.JSObject;
                slot.JSHandle = value.JSHandle;
            }
        }

        /// <summary>
        /// Implementation of the argument marshaling.
        /// It's used by JSImport code generator and should not be used by developers in source code.
        /// </summary>
        /// <param name="value">The value to be marshaled.</param>
#if !DEBUG
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
#endif
        public unsafe void ToManaged(out JSObject?[]? value)
        {
            if (slot.Type == MarshalerType.None)
            {
                value = null;
                return;
            }

            value = new JSObject?[slot.Length];
            JSMarshalerArgument* payload = (JSMarshalerArgument*)slot.IntPtrValue;
            for (int i = 0; i < slot.Length; i++)
            {
                ref JSMarshalerArgument arg = ref payload[i];
                JSObject? val;
                arg.ToManaged(out val);
                value[i] = val;
            }
            NativeMemory.Free((void*)slot.IntPtrValue);
        }

        /// <summary>
        /// Implementation of the argument marshaling.
        /// It's used by JSImport code generator and should not be used by developers in source code.
        /// </summary>
        /// <param name="value">The value to be marshaled.</param>
#if !DEBUG
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
#endif
        public unsafe void ToJS(JSObject?[] value)
        {
            if (value == null)
            {
                slot.Type = MarshalerType.None;
                return;
            }
            slot.Length = value.Length;
            int bytes = value.Length * sizeof(JSMarshalerArgument);
            slot.Type = MarshalerType.Array;
            slot.ElementType = MarshalerType.JSObject;
            JSMarshalerArgument* payload = (JSMarshalerArgument*)NativeMemory.Alloc((nuint)bytes);
            Unsafe.InitBlock(payload, 0, (uint)bytes);
            for (int i = 0; i < slot.Length; i++)
            {
                ref JSMarshalerArgument arg = ref payload[i];
                JSObject? val = value[i];
                arg.ToJS(val);
                value[i] = val;
            }
            slot.IntPtrValue = (IntPtr)payload;
        }
    }
}