package main

import (
	"fmt"
	"strings"
)

// Message key constants for i18n.
const (
	MsgCommandEmpty         = "command.empty"
	MsgCommandUnknown       = "command.unknown"
	MsgNotConfigured        = "requestbook.not_configured"
	MsgUsage                = "requestbook.usage"
	MsgSearchFailed         = "requestbook.search_failed"
	MsgNoBooksFound         = "requestbook.no_books_found"
	MsgQueueFailed          = "requestbook.queue_failed"
	MsgBookFound            = "requestbook.book_found"
	MsgLanguageInfo         = "requestbook.language_info"
	MsgDownloadTimeout      = "job.download_timeout"
	MsgNoReleases           = "job.no_releases"
	MsgNoReleasesFound      = "job.no_releases_found"
	MsgDownloadStartFailed  = "job.download_start_failed"
	MsgShelfmarkError       = "job.shelfmark_error"
	MsgTrackingLost         = "job.tracking_lost"
	MsgDownloadStatus       = "job.download_status"
	MsgDownloadFailed       = "job.download_failed"
	MsgPostFailed           = "job.post_failed"
	MsgUploadFailed         = "job.upload_failed"
	MsgAttachFailed         = "job.attach_failed"
	MsgTeamNotAllowed       = "command.team_not_allowed"
	MsgChannelNotFound      = "config.channel_not_found"
	MsgShelfmarkUnreachable = "config.shelfmark_unreachable"
)

// messages maps locale → key → format string.
var messages = map[string]map[string]string{
	"en": {
		MsgCommandEmpty:         "Empty command received.",
		MsgCommandUnknown:       "Unknown command: %s",
		MsgNotConfigured:        "Plugin is not configured: %s",
		MsgUsage:                "Usage: `/requestbook [--language <code>] <search query>`\nExample: `/requestbook The Hitchhiker's Guide to the Galaxy`\nExample: `/requestbook --language es Don Quixote`",
		MsgSearchFailed:         "Failed to search for books. Please check the plugin configuration and try again.",
		MsgNoBooksFound:         "No books found for \"%s\".",
		MsgQueueFailed:          "Failed to queue the book request. Please try again.",
		MsgBookFound:            "Book \"%s\" found%s. The download has been queued and will be posted when ready.",
		MsgLanguageInfo:         " (language: %s)",
		MsgDownloadTimeout:      "Download for \"%s\" timed out. Please try again.",
		MsgNoReleases:           "Could not find any downloadable files for \"%s\".",
		MsgNoReleasesFound:      "No downloadable files were found for \"%s\".",
		MsgDownloadStartFailed:  "Failed to start the download for \"%s\". Please try again.",
		MsgShelfmarkError:       "Shelfmark could not process the download for \"%s\".",
		MsgTrackingLost:         "The download for \"%s\" could not be tracked on Shelfmark.",
		MsgDownloadStatus:       "The download for \"%s\" has %s on Shelfmark.",
		MsgDownloadFailed:       "Failed to download \"%s\" from Shelfmark.",
		MsgPostFailed:           "Failed to create the book post for \"%s\".",
		MsgUploadFailed:         "Failed to upload the file for \"%s\".",
		MsgAttachFailed:         "Failed to attach the file for \"%s\".",
		MsgTeamNotAllowed:       "This plugin is not available on this team.",
		MsgChannelNotFound:      "The configured channel ID does not exist.",
		MsgShelfmarkUnreachable: "Cannot reach the Shelfmark server.",
	},
	"es": {
		MsgCommandEmpty:         "Comando vacío recibido.",
		MsgCommandUnknown:       "Comando desconocido: %s",
		MsgNotConfigured:        "El plugin no está configurado: %s",
		MsgUsage:                "Uso: `/requestbook [--language <código>] <búsqueda>`\nEjemplo: `/requestbook The Hitchhiker's Guide to the Galaxy`\nEjemplo: `/requestbook --language es Don Quixote`",
		MsgSearchFailed:         "Error al buscar libros. Por favor, compruebe la configuración del plugin e inténtelo de nuevo.",
		MsgNoBooksFound:         "No se encontraron libros para \"%s\".",
		MsgQueueFailed:          "Error al encolar la solicitud del libro. Por favor, inténtelo de nuevo.",
		MsgBookFound:            "Libro \"%s\" encontrado%s. La descarga ha sido añadida a la cola y se publicará cuando esté lista.",
		MsgLanguageInfo:         " (idioma: %s)",
		MsgDownloadTimeout:      "La descarga de \"%s\" ha expirado. Por favor, inténtelo de nuevo.",
		MsgNoReleases:           "No se encontraron archivos descargables para \"%s\".",
		MsgNoReleasesFound:      "No se encontraron archivos descargables para \"%s\".",
		MsgDownloadStartFailed:  "Error al iniciar la descarga de \"%s\". Por favor, inténtelo de nuevo.",
		MsgShelfmarkError:       "Shelfmark no pudo procesar la descarga de \"%s\".",
		MsgTrackingLost:         "No se pudo rastrear la descarga de \"%s\" en Shelfmark.",
		MsgDownloadStatus:       "La descarga de \"%s\" tiene estado %s en Shelfmark.",
		MsgDownloadFailed:       "Error al descargar \"%s\" desde Shelfmark.",
		MsgPostFailed:           "Error al crear la publicación del libro \"%s\".",
		MsgUploadFailed:         "Error al subir el archivo de \"%s\".",
		MsgAttachFailed:         "Error al adjuntar el archivo de \"%s\".",
		MsgTeamNotAllowed:       "Este plugin no está disponible en este equipo.",
		MsgChannelNotFound:      "El canal configurado no existe.",
		MsgShelfmarkUnreachable: "No se puede conectar con el servidor Shelfmark.",
	},
}

// T returns a localized, formatted message. Falls back to English if the locale
// or key is not found.
func T(locale, key string, args ...any) string {
	format := localizedMessage(locale, key)
	if len(args) == 0 {
		return format
	}
	return fmt.Sprintf(format, args...)
}

// localizedMessage resolves the format string for a given locale and key.
// It normalizes locales like "es-ES" → "es" and falls back to "en".
func localizedMessage(locale, key string) string {
	normalized := normalizeLocale(locale)

	if msgs, ok := messages[normalized]; ok {
		if format, ok := msgs[key]; ok {
			return format
		}
	}

	// Fallback to English.
	if msgs, ok := messages["en"]; ok {
		if format, ok := msgs[key]; ok {
			return format
		}
	}

	return key
}

// normalizeLocale extracts the base language from a locale string (e.g., "es-ES" → "es").
func normalizeLocale(locale string) string {
	if locale == "" {
		return "en"
	}
	parts := strings.SplitN(locale, "-", 2)
	return strings.ToLower(parts[0])
}