package modelselection

import (
	"voicesnap/internal/config"
	"voicesnap/internal/language"
	"voicesnap/internal/logger"
	"voicesnap/internal/model"
)

type CurrentModel struct {
	ModelID          string
	Profile          model.ModelProfile
	SelectionMode    string
	LanguageSettings language.LanguageSettings
	FallbackReason   string
}

func Resolve(cfg *config.Config, detector language.SystemLocaleDetector) CurrentModel {
	if cfg == nil {
		cfg = config.Default()
	}

	settings := language.Resolve(cfg.LanguageMode, cfg.LanguageID, detector)
	selectionMode := config.NormalizeModelSelectionMode(cfg.ModelSelectionMode)
	modelID := settings.DefaultModelID
	fallbackReason := ""

	if selectionMode == config.ModelSelectionModeManual {
		if profile, err := model.GetModelProfile(cfg.SelectedModelID); err == nil {
			if !model.IsModelSupportedInCurrentBuild(profile.ID) {
				fallbackReason = "manual model not supported in current build"
				logger.Info("Manual SelectedModelID %q is not supported in this build, falling back to language default %q", cfg.SelectedModelID, modelID)
			} else if isModelAvailableForLanguage(profile.ID, settings.EffectiveLanguageID) {
				return CurrentModel{
					ModelID:          profile.ID,
					Profile:          profile,
					SelectionMode:    selectionMode,
					LanguageSettings: settings,
				}
			} else {
				fallbackReason = "manual model not available for language"
				logger.Info("Manual SelectedModelID %q is not available for language %q, falling back to language default %q", cfg.SelectedModelID, settings.EffectiveLanguageID, modelID)
			}
		} else {
			fallbackReason = "invalid manual model selection"
			logger.Info("Invalid manual SelectedModelID %q, falling back to language default %q", cfg.SelectedModelID, modelID)
		}
	}

	profile, err := model.GetModelProfile(modelID)
	if err != nil {
		fallbackReason = "invalid language default model"
		logger.Info("Invalid default model %q for language %q, falling back to %q", modelID, settings.EffectiveLanguageID, model.DefaultModelID)
		profile = model.DefaultModelProfile()
		modelID = profile.ID
	} else if !model.IsModelSupportedInCurrentBuild(profile.ID) {
		fallbackReason = "language default model not supported in current build"
		logger.Info("Default model %q for language %q is not supported in this build, falling back to %q", modelID, settings.EffectiveLanguageID, model.DefaultModelID)
		profile = model.DefaultModelProfile()
		modelID = profile.ID
	}

	return CurrentModel{
		ModelID:          modelID,
		Profile:          profile,
		SelectionMode:    selectionMode,
		LanguageSettings: settings,
		FallbackReason:   fallbackReason,
	}
}

func isModelAvailableForLanguage(modelID, languageID string) bool {
	if !model.IsModelSupportedInCurrentBuild(modelID) {
		return false
	}
	profile, err := model.GetLanguageProfile(languageID)
	if err != nil {
		return false
	}
	if profile.DefaultModelID == modelID {
		return true
	}
	for _, upgradeModelID := range profile.UpgradeModelIDs {
		if upgradeModelID == modelID {
			return true
		}
	}
	return false
}