package template

import (
	"fmt"
	"os"
	"path/filepath"
	"strings"

	"chat-agent-system/templates"
)

func findProjectRoot() string {
	wd, _ := os.Getwd()
	candidates := []string{wd}
	dir := wd
	for i := 0; i < 10; i++ {
		candidates = append(candidates, dir)
		parent := filepath.Dir(dir)
		if parent == dir {
			break
		}
		dir = parent
	}
	if env := strings.TrimSpace(os.Getenv("APP_ROOT")); env != "" {
		candidates = append(candidates, env)
	}
	// Image WORKDIR is /app; Dockerfile copies templates/configs here.
	candidates = append(candidates, "/app")
	for _, root := range candidates {
		if root == "" {
			continue
		}
		if _, err := os.Stat(filepath.Join(root, "templates", "docs")); err == nil {
			return root
		}
	}
	return wd
}

func GetDocTemplate(name string) (string, error) {
	name = strings.TrimSuffix(name, ".md")
	if name == "" || strings.Contains(name, "..") || strings.ContainsAny(name, `/\`) {
		return "", fmt.Errorf("read doc template: invalid name %q", name)
	}
	if b, err := templates.DocTemplates.ReadFile("docs/" + name + ".md"); err == nil && len(strings.TrimSpace(string(b))) > 0 {
		return string(b), nil
	}
	root := findProjectRoot()
	path := filepath.Join(root, "templates", "docs", name+".md")
	b, err := os.ReadFile(path)
	if err != nil {
		return "", fmt.Errorf("read doc template %s: %w", name, err)
	}
	return string(b), nil
}

func GetAgentInstruction(role string) (string, error) {
	role = strings.TrimSuffix(role, ".md")
	root := findProjectRoot()
	path := filepath.Join(root, "configs", "agents", role+".md")
	b, err := os.ReadFile(path)
	if err != nil {
		return "", fmt.Errorf("read agent instruction %s: %w", role, err)
	}

	inst := string(b)
	writingPath := filepath.Join(root, "configs", "shared", "writing.md")
	if wb, err := os.ReadFile(writingPath); err == nil {
		inst += "\n\n" + string(wb)
	}
	return inst, nil
}