import { defineStore } from 'pinia'
import { ref, watch, computed } from 'vue'
import { translations } from '../utils/i18n'

// Settings persisted in localStorage under 'llm-in-text-settings'
const SETTINGS_KEY = 'llm-in-text-settings'

export const useSettingsStore = defineStore('settings', () => {
    // --- Reactive state (all auto-tracked by watch below) ---
    const theme = ref('system')           // 'light' | 'dark' | 'system'
    const modelThinking = ref('low')      // 'low' | 'medium' | 'high'
    const debounceMs = ref(1000)          // 1000 - 5000
    const proThinking = ref('medium')     // 'low' | 'medium' | 'high'
    const privacyMode = ref(true)
    const language = ref('auto')
    const currency = ref('auto')
    const backgroundType = ref('default') // 'default' | 'warm' | 'reading' | 'image'
    const backgroundImage = ref('')
    const backgroundOpacity = ref(0.2)    // 0.05 - 0.50
    const ttsInstruct = ref('')

    // --- Computed getters (derived from reactive state) ---
    const uiLanguage = computed(() => {
        if (language.value !== 'auto') return language.value
        const sysLang = (navigator.language || navigator.userLanguage || 'en').split('-')[0]
        return ['zh', 'en', 'ja', 'ko', 'de', 'fr'].includes(sysLang) ? sysLang : 'en'
    })

    const detectedTimezone = computed(() => Intl.DateTimeFormat().resolvedOptions().timeZone || 'UTC')
    const t = computed(() => ({ ...translations['en'], ...(translations[uiLanguage.value] || {}) }))
    const initialMarkdown = computed(() => translations[uiLanguage.value]?.initialMarkdown || translations['en']?.initialMarkdown || '')

    // --- localStorage persistence ---
    const loadSettings = () => {
        try {
            const stored = localStorage.getItem(SETTINGS_KEY)
            if (!stored) return
            const data = JSON.parse(stored)
            // Restore each field with type guards
            if (data.theme) theme.value = data.theme
            if (data.modelThinking) modelThinking.value = data.modelThinking
            if (data.debounceMs) debounceMs.value = data.debounceMs
            if (data.proThinking) proThinking.value = data.proThinking
            if (typeof data.privacyMode === 'boolean') privacyMode.value = data.privacyMode
            if (data.language) language.value = data.language
            if (data.currency) currency.value = data.currency
            if (data.backgroundType === 'color') backgroundType.value = 'default'
            else if (data.backgroundType) backgroundType.value = data.backgroundType
            if (data.backgroundImage) backgroundImage.value = data.backgroundImage
            if (data.backgroundOpacity) backgroundOpacity.value = data.backgroundOpacity
            if (typeof data.ttsInstruct === 'string') ttsInstruct.value = data.ttsInstruct
        } catch { /* use defaults */ }
    }

    const saveSettings = () => {
        try {
            localStorage.setItem(SETTINGS_KEY, JSON.stringify({
                theme: theme.value, modelThinking: modelThinking.value,
                debounceMs: debounceMs.value, proThinking: proThinking.value,
                privacyMode: privacyMode.value, language: language.value,
                currency: currency.value, backgroundType: backgroundType.value,
                backgroundImage: backgroundImage.value, backgroundOpacity: backgroundOpacity.value,
                ttsInstruct: ttsInstruct.value,
            }))
        } catch { /* silently fail */ }
    }

    const resetSettings = () => {
        theme.value = 'system'; modelThinking.value = 'low'; debounceMs.value = 1000
        proThinking.value = 'medium'; privacyMode.value = false; language.value = 'auto'
        currency.value = 'auto'; backgroundType.value = 'default'; backgroundImage.value = ''
        backgroundOpacity.value = 0.2; ttsInstruct.value = ''; saveSettings()
    }

    // Watch all reactive refs and auto-save on change
    watch([theme, modelThinking, debounceMs, proThinking, privacyMode, language, currency
        , backgroundType, backgroundImage, backgroundOpacity, ttsInstruct], saveSettings)

    loadSettings() // Initialize from localStorage

    return { theme, modelThinking, debounceMs, proThinking, privacyMode, language
        , currency, backgroundType, backgroundImage, backgroundOpacity, ttsInstruct
        , detectedTimezone, uiLanguage, t, initialMarkdown, resetSettings }
})