//go:build cshared

// Command billing is the thin C ABI entry point for CLIProxyAPI.
package main

/*
#include <stdint.h>
#include <stdlib.h>

typedef struct {
	void* ptr;
	size_t len;
} cliproxy_buffer;

typedef int (*cliproxy_host_call_fn)(void*, const char*, const uint8_t*, size_t, cliproxy_buffer*);
typedef void (*cliproxy_host_free_fn)(void*, size_t);

typedef struct {
	uint32_t abi_version;
	void* host_ctx;
	cliproxy_host_call_fn call;
	cliproxy_host_free_fn free_buffer;
} cliproxy_host_api;

typedef int (*cliproxy_plugin_call_fn)(char*, uint8_t*, size_t, cliproxy_buffer*);
typedef void (*cliproxy_plugin_free_fn)(void*, size_t);
typedef void (*cliproxy_plugin_shutdown_fn)(void);

typedef struct {
	uint32_t abi_version;
	cliproxy_plugin_call_fn call;
	cliproxy_plugin_free_fn free_buffer;
	cliproxy_plugin_shutdown_fn shutdown;
} cliproxy_plugin_api;

extern int cliproxyPluginCall(char*, uint8_t*, size_t, cliproxy_buffer*);
extern void cliproxyPluginFree(void*, size_t);
extern void cliproxyPluginShutdown(void);

static const cliproxy_host_api* stored_host;

static void store_host_api(const cliproxy_host_api* host) {
	stored_host = host;
}

static int call_host_api(const char* method, const uint8_t* request, size_t request_len, cliproxy_buffer* response) {
	if (stored_host == NULL || stored_host->call == NULL) {
		return 1;
	}
	return stored_host->call(stored_host->host_ctx, method, request, request_len, response);
}

static void free_host_buffer(void* ptr, size_t len) {
	if (stored_host != NULL && stored_host->free_buffer != NULL && ptr != NULL) {
		stored_host->free_buffer(ptr, len);
	}
}
*/
import "C"

import (
	"fmt"
	"net/http"
	"unsafe"

	"billing/internal/plugin"
)

var app = plugin.NewApp()

func main() {}

//export cliproxy_plugin_init
func cliproxy_plugin_init(host *C.cliproxy_host_api, api *C.cliproxy_plugin_api) C.int {
	if api == nil {
		return 1
	}
	C.store_host_api(host)
	app.SetHostCaller(cHostCaller{})
	api.abi_version = C.uint32_t(plugin.ABIVersion)
	api.call = C.cliproxy_plugin_call_fn(C.cliproxyPluginCall)
	api.free_buffer = C.cliproxy_plugin_free_fn(C.cliproxyPluginFree)
	api.shutdown = C.cliproxy_plugin_shutdown_fn(C.cliproxyPluginShutdown)
	return 0
}

type cHostCaller struct{}

func (cHostCaller) Call(method string, request []byte) ([]byte, error) {
	cMethod := C.CString(method)
	defer C.free(unsafe.Pointer(cMethod))
	var response C.cliproxy_buffer
	var requestPtr *C.uint8_t
	if len(request) > 0 {
		requestPtr = (*C.uint8_t)(C.CBytes(request))
		defer C.free(unsafe.Pointer(requestPtr))
	}
	if status := C.call_host_api(cMethod, requestPtr, C.size_t(len(request)), &response); status != 0 {
		return nil, fmt.Errorf("host callback %s failed with status %d", method, int(status))
	}
	if response.ptr == nil || response.len == 0 {
		return nil, nil
	}
	defer C.free_host_buffer(response.ptr, response.len)
	return C.GoBytes(response.ptr, C.int(response.len)), nil
}

//export cliproxyPluginCall
func cliproxyPluginCall(method *C.char, request *C.uint8_t, requestLen C.size_t, response *C.cliproxy_buffer) C.int {
	if response != nil {
		response.ptr = nil
		response.len = 0
	}
	if method == nil {
		writeResponse(response, plugin.ErrorEnvelope("invalid_method", "缺少插件方法", http.StatusBadRequest))
		return 1
	}
	var requestBytes []byte
	if request != nil && requestLen > 0 {
		requestBytes = C.GoBytes(unsafe.Pointer(request), C.int(requestLen))
	}
	raw, err := app.HandleMethod(C.GoString(method), requestBytes)
	if err != nil {
		writeResponse(response, plugin.ErrorEnvelope("plugin_error", err.Error(), http.StatusInternalServerError))
		return 1
	}
	writeResponse(response, raw)
	return 0
}

//export cliproxyPluginFree
func cliproxyPluginFree(ptr unsafe.Pointer, _ C.size_t) {
	if ptr != nil {
		C.free(ptr)
	}
}

//export cliproxyPluginShutdown
func cliproxyPluginShutdown() {
	app.Shutdown()
}

func writeResponse(response *C.cliproxy_buffer, raw []byte) {
	if response == nil || len(raw) == 0 {
		return
	}
	ptr := C.CBytes(raw)
	if ptr == nil {
		return
	}
	response.ptr = ptr
	response.len = C.size_t(len(raw))
}