package exec

import (
	"fmt"
	"io"

	wasiv1 "code.icb4dc0.de/buildr/api/generated/wasi/v1"
	"code.icb4dc0.de/buildr/wasi-module-sdk-go/mem"
)

func NewCommand(name string, args ...string) *Command {
	return &Command{
		Name: name,
		Args: args,
	}
}

type Command struct {
	Name       string
	Args       []string
	WorkingDir string
	Env        map[string]string
	StdIn      io.Reader
}

func (c *Command) AddEnv(envToAdd map[string]string) {
	if envToAdd == nil {
		return
	}

	if c.Env == nil {
		c.Env = make(map[string]string)
	}

	for k, v := range envToAdd {
		c.Env[k] = v
	}
}

func (c *Command) Run() error {
	execReq := &wasiv1.ProcessStartRequest{
		Command:          c.Name,
		Args:             c.Args,
		WorkingDirectory: c.WorkingDir,
		Environment:      c.Env,
	}

	if c.StdIn != nil {
		if stdInData, err := io.ReadAll(c.StdIn); err != nil {
			return err
		} else {
			execReq.Stdin = stdInData
		}
	}

	data, err := execReq.MarshalVT()
	if err != nil {
		return err
	}

	result := _exec(mem.DataToManagedPtr(data))
	if result == 0 {
		return fmt.Errorf("failed to execute command: %s", c.Name)
	}

	resultPtr := uint32(result >> 32)
	resultSize := uint32(result)

	if resultSize == 0 {
		return nil
	}

	execResp := new(wasiv1.ProcessStartResponse)
	if err := execResp.UnmarshalVT(mem.PtrToData(resultPtr, resultSize)); err != nil {
		return err
	}

	if execResp.ExitCode != 0 {
		return &Error{
			ExitCode: int(execResp.ExitCode),
			Message:  execResp.Error,
			StdErr:   execResp.Stderr,
		}
	}

	return nil
}