package service

import (
	"errors"
	"fmt"
	"path"
	"path/filepath"
	"strings"
)

func strmTreeRelativeSource(source, sourceRoot string) string {
	source = normalizeSTRMTreeSource(source)
	root := normalizeRemotePath(sourceRoot)
	if root != "/" && strings.HasPrefix(source, root+"/") {
		return strings.TrimPrefix(strings.TrimPrefix(source, root), "/")
	}
	return strings.TrimPrefix(source, "/")
}

func strmTreeCloudRef(source, sourceRoot string) string {
	source = normalizeSTRMTreeSource(source)
	if strings.HasPrefix(source, "/") {
		return source
	}
	if strings.TrimSpace(sourceRoot) != "" {
		return joinRemotePath(sourceRoot, source)
	}
	return normalizeRemotePath(source)
}

func strmTreeOutputRelativePath(source string) (string, error) {
	parts := strings.Split(strings.Trim(strings.ReplaceAll(source, "\\", "/"), "/"), "/")
	if len(parts) == 0 {
		return "", errors.New("empty source path")
	}
	out := make([]string, 0, len(parts))
	for i, part := range parts {
		part = strings.TrimSpace(part)
		if part == "" || part == "." || part == ".." {
			return "", fmt.Errorf("unsafe path segment %q", part)
		}
		if i == len(parts)-1 {
			ext := strings.ToLower(path.Ext(part))
			if _, ok := videoExtensions[ext]; !ok {
				return "", fmt.Errorf("unsupported media extension %q", ext)
			}
			part = strings.TrimSuffix(part, path.Ext(part)) + ".strm"
		}
		safe := sanitizeFilename(part)
		if safe == "" {
			return "", errors.New("empty sanitized path segment")
		}
		out = append(out, safe)
	}
	return filepath.Join(out...), nil
}

func strmTreeOutputPrefixPath(prefix string) (string, error) {
	parts := strings.Split(strings.Trim(strings.ReplaceAll(prefix, "\\", "/"), "/"), "/")
	out := make([]string, 0, len(parts))
	for _, part := range parts {
		part = strings.TrimSpace(part)
		if part == "" {
			continue
		}
		if part == "." || part == ".." {
			return "", fmt.Errorf("unsafe output prefix segment %q", part)
		}
		safe := sanitizeFilename(part)
		if safe == "" {
			return "", errors.New("empty sanitized output prefix segment")
		}
		out = append(out, safe)
	}
	return filepath.Join(out...), nil
}