//go:build js && wasm

package auth

import (
	"encoding/json"
	"fmt"
	"net/url"
	"syscall/js"
)

// WASMHTTPClient handles HTTP requests in WASM environment
type WASMHTTPClient struct{}

// HTTPResult represents the result of an HTTP request
type HTTPResult struct {
	Data  []byte
	Error error
}

// HTTPCallback is called when HTTP request completes
type HTTPCallback func(result HTTPResult)

// FetchJSON performs a GET request and unmarshals JSON response
// This method blocks and should only be called from the main thread
func (c *WASMHTTPClient) FetchJSON(url string, dest interface{}) error {
	result := make(chan HTTPResult, 1)

	c.FetchJSONAsync(url, func(r HTTPResult) {
		result <- r
	})

	r := <-result
	if r.Error != nil {
		return r.Error
	}

	return json.Unmarshal(r.Data, dest)
}

// FetchJSONAsync performs a GET request asynchronously using callback
func (c *WASMHTTPClient) FetchJSONAsync(url string, callback HTTPCallback) {
	// Create fetch promise
	promise := js.Global().Call("fetch", url)

	// Success handler
	var successFunc js.Func
	successFunc = js.FuncOf(func(this js.Value, args []js.Value) interface{} {
		response := args[0]
		if !response.Get("ok").Bool() {
			callback(HTTPResult{
				Error: fmt.Errorf("HTTP %d: %s", response.Get("status").Int(), response.Get("statusText").String()),
			})
			successFunc.Release()
			return nil
		}

		// Get response text
		textPromise := response.Call("text")
		var textFunc js.Func
		textFunc = js.FuncOf(func(this js.Value, args []js.Value) interface{} {
			text := args[0].String()
			callback(HTTPResult{
				Data: []byte(text),
			})
			// Cleanup after callback completes
			textFunc.Release()
			successFunc.Release()
			return nil
		})

		// Error handler for text promise
		var textErrorFunc js.Func
		textErrorFunc = js.FuncOf(func(this js.Value, args []js.Value) interface{} {
			callback(HTTPResult{
				Error: fmt.Errorf("failed to read response text: %v", args[0]),
			})
			// Cleanup
			textFunc.Release()
			textErrorFunc.Release()
			successFunc.Release()
			return nil
		})

		textPromise.Call("then", textFunc).Call("catch", textErrorFunc)
		return nil
	})

	// Error handler
	var errorFunc js.Func
	errorFunc = js.FuncOf(func(this js.Value, args []js.Value) interface{} {
		callback(HTTPResult{
			Error: fmt.Errorf("fetch error: %s", args[0].String()),
		})
		// Cleanup after callback completes
		errorFunc.Release()
		successFunc.Release()
		return nil
	})

	promise.Call("then", successFunc).Call("catch", errorFunc)
}

// PostForm performs a POST request with form data
func (c *WASMHTTPClient) PostForm(url string, data url.Values, dest interface{}) error {
	result := make(chan HTTPResult, 1)

	c.PostFormAsync(url, data, func(r HTTPResult) {
		result <- r
	})

	r := <-result
	if r.Error != nil {
		return r.Error
	}

	return json.Unmarshal(r.Data, dest)
}

// PostFormAsync performs a POST request asynchronously using callback
func (c *WASMHTTPClient) PostFormAsync(url string, data url.Values, callback HTTPCallback) {
	// Prepare fetch options
	headers := map[string]interface{}{
		"Content-Type": "application/x-www-form-urlencoded",
	}

	options := map[string]interface{}{
		"method":  "POST",
		"headers": headers,
		"body":    data.Encode(),
	}

	// Convert options to JS object
	jsOptions := js.ValueOf(options)

	// Make the request
	promise := js.Global().Call("fetch", url, jsOptions)

	// Success handler
	var successFunc js.Func
	successFunc = js.FuncOf(func(this js.Value, args []js.Value) interface{} {
		response := args[0]
		if !response.Get("ok").Bool() {
			callback(HTTPResult{
				Error: fmt.Errorf("HTTP %d: %s", response.Get("status").Int(), response.Get("statusText").String()),
			})
			successFunc.Release()
			return nil
		}

		// Get response text
		textPromise := response.Call("text")
		var textFunc js.Func
		textFunc = js.FuncOf(func(this js.Value, args []js.Value) interface{} {
			text := args[0].String()
			callback(HTTPResult{
				Data: []byte(text),
			})
			// Cleanup after callback completes
			textFunc.Release()
			successFunc.Release()
			return nil
		})

		// Error handler for text promise
		var textErrorFunc js.Func
		textErrorFunc = js.FuncOf(func(this js.Value, args []js.Value) interface{} {
			callback(HTTPResult{
				Error: fmt.Errorf("failed to read response text: %v", args[0]),
			})
			// Cleanup
			textFunc.Release()
			textErrorFunc.Release()
			successFunc.Release()
			return nil
		})

		textPromise.Call("then", textFunc).Call("catch", textErrorFunc)
		return nil
	})

	// Error handler
	var errorFunc js.Func
	errorFunc = js.FuncOf(func(this js.Value, args []js.Value) interface{} {
		callback(HTTPResult{
			Error: fmt.Errorf("fetch error: %s", args[0].String()),
		})
		// Cleanup after callback completes
		errorFunc.Release()
		successFunc.Release()
		return nil
	})

	promise.Call("then", successFunc).Call("catch", errorFunc)
}