package feeds

import (
	"errors"

	"github.com/jackc/pgx/v5"
)

// ErrFormatMismatch is returned when the public export URL extension does not
// match the feed's configured format. Public HTTP handlers must map this to the
// same opaque 404 as an unknown token (no existence oracle).
var ErrFormatMismatch = errors.New("format mismatch")

// ErrNotFound is returned when a company-scoped feed (or related row) is missing.
var ErrNotFound = errors.New("not found")

// clientError is a validation/business message safe to return to API clients.
type clientError struct {
	msg string
}

func (e *clientError) Error() string { return e.msg }

// ClientMsg marks a message as safe to expose in HTTP 4xx responses.
func ClientMsg(msg string) error {
	return &clientError{msg: msg}
}

// ClientError reports whether err is a known client-facing feeds error.
func ClientError(err error) (msg string, ok bool) {
	if err == nil {
		return "", false
	}
	var ce *clientError
	if errors.As(err, &ce) {
		return ce.msg, true
	}
	switch {
	case errors.Is(err, ErrNotFound), errors.Is(err, pgx.ErrNoRows):
		return "not found", true
	case errors.Is(err, ErrFormatMismatch),
		errors.Is(err, errURLRequired),
		errors.Is(err, errURLScheme),
		errors.Is(err, errURLPrivate),
		errors.Is(err, errURLFTP),
		errors.Is(err, errDownloadTooLarge),
		errors.Is(err, errParseTooManyRows),
		errors.Is(err, errSourceRequired),
		errors.Is(err, errLocalSource):
		return err.Error(), true
	default:
		return "", false
	}
}

// IsNotFound reports whether err means a missing feed/resource.
func IsNotFound(err error) bool {
	return errors.Is(err, ErrNotFound) || errors.Is(err, pgx.ErrNoRows)
}