// WASM-PROPOSAL Phase 3 — dynamic-loader core scaffold.
//
// This core owns the UCE heap, Request, DValue/UCEB1, and output buffer. The
// Phase 3 loader dynamically links a PIC side module generated in the same
// shape as UCE preprocessor output, sets its Request* context, and invokes its
// __uce_render entry.

#include <cstdlib>
#include <cstring>
#include <functional>

#include "../../src/lib/types.h"
#include "../../src/lib/dvalue.cpp"

extern "C" {
size_t uce_host_ctx_read(char* buf, size_t cap);
void uce_host_log(int level, const char* buf, size_t len);
}

extern "C" void phase3_core_print(const char* data, size_t len)
{
	if(context && context->ob)
		context->ob->write(data, len);
}

extern "C" void phase3_core_invoke_callback(void (*cb)(int), int value)
{
	cb(value);
}

extern "C" void phase3_core_invoke_function(std::function<int(int)>* f, int value)
{
	String out = "<p>fn=" + std::to_string((*f)(value)) + "</p>\n";
	phase3_core_print(out.data(), out.size());
}

extern "C" intptr_t core_table_index_of_phase3_core_print()
{
	return(reinterpret_cast<intptr_t>(phase3_core_print));
}

static Request g_request;
static ByteStream g_ob;
static String g_output;

SharedUnit::~SharedUnit() {}

String html_escape(String s)
{
	String result;
	for(char c : s)
	{
		switch(c)
		{
			case '&': result += "&amp;"; break;
			case '<': result += "&lt;"; break;
			case '>': result += "&gt;"; break;
			case '"': result += "&quot;"; break;
			case '\'': result += "&#39;"; break;
			default: result.push_back(c); break;
		}
	}
	return(result);
}

String nibble(String div, String& haystack)
{
	auto pos = haystack.find(div);
	if(pos == String::npos)
	{
		auto result = haystack;
		haystack.clear();
		return(result);
	}
	auto result = haystack.substr(0, pos);
	haystack.erase(0, pos + div.length());
	return(result);
}

void Request::ob_start()
{
	ob_stack.push_back(new ByteStream());
	ob = ob_stack.back();
}

void Request::set_status(s32 code, String reason)
{
	if(reason == "")
		reason = code == 200 ? "OK" : "Status";
	response_code = "HTTP/1.1 " + std::to_string(code) + " " + reason;
}

Request::~Request()
{
	for(auto* stream : ob_stack)
		delete stream;
	ob_stack.clear();
}

static void phase3_clear_ob_stack()
{
	for(auto* stream : g_request.ob_stack)
		delete stream;
	g_request.ob_stack.clear();
}

static void phase3_apply_context(DValue& root)
{
	g_request.call = root;
	g_request.params.clear();
	DValue* params = root.key("params");
	if(params)
	{
		params->each([&](const DValue& item, String key) {
			g_request.params[key] = item.to_string();
		});
	}
}

extern "C" {

void* uce_alloc(size_t len)
{
	return(malloc(len));
}

void uce_free(void* ptr)
{
	free(ptr);
}

int uce_phase3_prepare()
{
	context = &g_request;
	phase3_clear_ob_stack();
	g_ob.str("");
	g_ob.clear();
	g_request.ob = &g_ob;
	g_request.out = "";
	g_output = "";

	size_t ctx_required = uce_host_ctx_read(0, 0);
	if(ctx_required == 0)
		return(10);
	char* ctx_buf = (char*)malloc(ctx_required);
	if(ctx_buf == 0)
		return(11);
	size_t ctx_len = uce_host_ctx_read(ctx_buf, ctx_required);
	if(ctx_len != ctx_required)
	{
		free(ctx_buf);
		return(12);
	}

	DValue decoded;
	String error;
	bool ok = ucb_decode(String(ctx_buf, ctx_len), decoded, &error);
	free(ctx_buf);
	if(!ok)
	{
		uce_host_log(3, error.data(), error.size());
		return(20);
	}
	phase3_apply_context(decoded);
	return(0);
}

Request* uce_phase3_request()
{
	return(&g_request);
}

void uce_phase3_finish()
{
	g_output = g_ob.str();
}

const char* uce_phase3_output_data()
{
	return(g_output.data());
}

size_t uce_phase3_output_size()
{
	return(g_output.size());
}

}