feat

- implemented spellcaster

go.mod

@@ -1 +1,5 @@
 module spellbook
+
+go 1.26.0
+
+require github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510 // indirect

go.sum

@@ -0,0 +1,2 @@
+github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510 h1:El6M4kTTCOh6aBiKaUGG7oYTSPP8MxqL4YI3kZKwcP4=
+github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510/go.mod h1:pupxD2MaaD3pAXIBCelhxNneeOaAeabZDe5s4K6zSpQ=

internal/adapters/caster/caster.go

@@ -0,0 +1,62 @@
+package caster
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"fmt"
+	"github.com/google/shlex"
+	"os/exec"
+	"spellbook/internal/models"
+	"text/template"
+	"time"
+)
+
+type SpellCaster struct{}
+
+func (sc *SpellCaster) Cast(ctx context.Context, cast models.SpellCast) (models.CastResult, error) {
+	args, err := renderSpell(cast)
+	if err != nil {
+		return models.CastResult{}, err
+	}
+
+	cmd := exec.CommandContext(ctx, args[0], args[1:]...)
+	cmd.Stdin = cast.Stdin
+	cmd.Stdout = cast.Stdout
+	cmd.Stderr = cast.Stderr
+
+	start := time.Now()
+	err = cmd.Run()
+	duration := time.Since(start)
+
+	res := models.CastResult{
+		Duration: duration,
+	}
+
+	if err != nil {
+		var exitErr *exec.ExitError
+		if errors.As(err, &exitErr) {
+			res.ExitCode = exitErr.ExitCode()
+			res.Err = err
+			return res, nil
+		}
+		return res, fmt.Errorf("failed to cast spell: %w", err)
+	}
+
+	res.ExitCode = 0
+	return res, nil
+}
+
+func renderSpell(cast models.SpellCast) ([]string, error) {
+	tmpl, err := template.New(cast.Spell.Name).Option("missingkey=error").Parse(cast.Spell.Spell)
+	if err != nil {
+		return nil, err
+	}
+
+	buf := bytes.NewBuffer(nil)
+	if err := tmpl.Execute(buf, cast.Args); err != nil {
+		return nil, err
+	}
+
+	return shlex.Split(buf.String())
+}

internal/models/models.go

@@ -14,12 +14,14 @@ type Spell struct {
 type SpellCast struct {
 	Spell  Spell
 	Args   map[string]string
+	Stdin  io.Reader
 	Stdout io.Writer
 	Stderr io.Writer
 }
 
 type CastResult struct {
 	ExitCode int
+	Err      error
 	Duration time.Duration
 	Meta     map[string]any
 }