package main

import (
	"github.com/extism/go-pdk"
)

func main() {}

//go:wasmimport extism:host/user a_python_func
func aPythonFunc(uint64) uint64

//export hello_from_python
func helloFromPython() int32 {
	msg := "An argument to send to Python"
	mem := pdk.AllocateString(msg)
	defer mem.Free()
	ptr := aPythonFunc(mem.Offset())
	rmem := pdk.FindMemory(ptr)
	response := string(rmem.ReadBytes())
	pdk.OutputString(response)
	return 0
}

from extism import host_fn, Function, ValType, Plugin

@host_fn
def a_python_func(plugin, input_, output, _user_data):
    # The plug-in is passing us a string
    input_str = plugin.input_string(input_[0])

    # just printing this out to prove we're in Python land
    print("Hello from Python!")

    # let's just add "!" to the input string
    # but you could imagine here we could add some
    # applicaiton code like query or manipulate the database
    # or our application APIs
    input_str += "!"
# 
    # set the new string as the return value to the plug-in
    plugin.return_string(output[0], input_str)

functions = [
    Function(
        "a_python_func",
        [ValType.I64],
        [ValType.I64],
        a_python_func,
        None
    )
]

manifest = {"wasm": [{"path": "./plugin.wasm"}]}
plugin = Plugin(manifest, functions=functions, wasi=True)
#result = plugin.call('hello_from_python').decode('utf-8') <- function name has a typo
result = plugin.call('helloFromPython').decode('utf-8')
print(result)

$ python app.py
Traceback (most recent call last):
  File "app.py", line 21, in <module>
    Function(
  File "/home/user/extism_wasm_test/lib/python3.8/site-packages/extism/extism.py", line 254, in __init__
    self.pointer = _lib.extism_function_new(
TypeError: initializer for ctype 'void(*)(struct ExtismCurrentPlugin *, ExtismVal *, unsigned long, ExtismVal *, unsigned long, void *)' must be a cdata pointer, not function

Mo in ~ λ go version
go version go1.20.5 windows/amd64
Mo in ~ λ tinygo version
tinygo version 0.28.1 windows/amd64 (using go version go1.20.5 and LLVM version 15.0.0)
Mo in D:\Explore\go\go-pdk\example on main ● ~1 λ tinygo build -o main.wasm .\main.go
wasm-ld: error: C:\Users\Mo\AppData\Local\Temp\tinygo3081171661\main.o: undefined symbol: extism_load_u64
wasm-ld: error: C:\Users\Mo\AppData\Local\Temp\tinygo3081171661\main.o: undefined symbol: extism_load_u8
wasm-ld: error: C:\Users\Mo\AppData\Local\Temp\tinygo3081171661\main.o: undefined symbol: extism_alloc
wasm-ld: error: C:\Users\Mo\AppData\Local\Temp\tinygo3081171661\main.o: undefined symbol: extism_store_u64
wasm-ld: error: C:\Users\Mo\AppData\Local\Temp\tinygo3081171661\main.o: undefined symbol: extism_store_u8
wasm-ld: error: C:\Users\Mo\AppData\Local\Temp\tinygo3081171661\main.o: undefined symbol: extism_var_get
wasm-ld: error: C:\Users\Mo\AppData\Local\Temp\tinygo3081171661\main.o: undefined symbol: extism_length
wasm-ld: error: C:\Users\Mo\AppData\Local\Temp\tinygo3081171661\main.o: undefined symbol: extism_input_length
wasm-ld: error: C:\Users\Mo\AppData\Local\Temp\tinygo3081171661\main.o: undefined symbol: extism_input_load_u64
wasm-ld: error: C:\Users\Mo\AppData\Local\Temp\tinygo3081171661\main.o: undefined symbol: extism_input_load_u8
wasm-ld: error: C:\Users\Mo\AppData\Local\Temp\tinygo3081171661\main.o: undefined symbol: extism_var_set
wasm-ld: error: C:\Users\Mo\AppData\Local\Temp\tinygo3081171661\main.o: undefined symbol: extism_config_get
wasm-ld: error: C:\Users\Mo\AppData\Local\Temp\tinygo3081171661\main.o: undefined symbol: extism_length
wasm-ld: error: C:\Users\Mo\AppData\Local\Temp\tinygo3081171661\main.o: undefined symbol: extism_output_set
failed to run tool: wasm-ld
error: failed to link C:\Users\Mo\AppData\Local\Temp\tinygo3081171661\main: exit status 1