// Package prompts provides the embedded system prompt template.
package prompts

import (
	_ "embed"
	"fmt"
	"os"
	"strings"
)

//go:embed system_prompt.md
var DefaultSystemPrompt string

// ResolveSystemPrompt expands env vars in overridePath, then tries to read the
// file from the filesystem. If the file doesn't exist, the embedded default is
// returned.
func ResolveSystemPrompt(overridePath string) string {
	if overridePath == "" {
		return DefaultSystemPrompt
	}
	expanded := os.Expand(overridePath, os.Getenv)
	data, err := os.ReadFile(expanded)
	if err == nil {
		return strings.TrimRight(string(data), "\n")
	}
	fmt.Fprintf(os.Stderr, "system_prompt %q: %v (using default)\n", expanded, err)
	return DefaultSystemPrompt
}