import { ref, computed } from 'vue'
import { requestAiStream, parsePartialDietPlainText } from '../utils/aiStreamRequest.js'

const DIET_AI_PREFILL_KEY = 'tongji_diet_ai_prefill'

const emptyDietAiRecommend = () => ({
    breakfast: '',
    lunch: '',
    dinner: '',
    tips: '',
    avoid: [],
    analysis: [],
    exercise: null,
    disclaimer: '',
    rules_summary: '',
    source: '',
    date: ''
})

/** AI 饮食助手（今日推荐 + 能不能吃） */
export function useDietAi(proxy, { diagnosisId, showUserToast, formatUserMessage }) {
    const dietAiRecommend = ref(emptyDietAiRecommend())
    const dietAiLoading = ref(false)
    const dietAiStreaming = ref(false)
    const dietAiReplacing = ref(false)
    const dietAiStreamField = ref('')
    let dietStreamBuffer = ''
    const dietAiAskText = ref('')
    const dietAiAsking = ref(false)
    const dietAiAskResult = ref({ advice: '', level: '', level_label: '', portion: '', food: '' })

    const hasDietAiMealContent = computed(() => {
        const r = dietAiRecommend.value
        return !!(r.breakfast || r.lunch || r.dinner || r.tips)
    })

    function detectDietStreamField(text) {
        const tail = String(text || '').match(/(?:^|\n)(早餐|午餐|晚餐|提示|少碰)[：:]\s*([^\n]*)$/)
        if (!tail) return 'breakfast'
        const map = { '早餐': 'breakfast', '午餐': 'lunch', '晚餐': 'dinner', '提示': 'tips', '少碰': 'tips' }
        return map[tail[1]] || 'breakfast'
    }

    function mergePartialDietFromStream() {
        const partial = parsePartialDietPlainText(dietStreamBuffer)
        const next = { ...dietAiRecommend.value }
        for (const key of ['breakfast', 'lunch', 'dinner', 'tips']) {
            if (partial[key] != null) next[key] = partial[key]
        }
        if (Array.isArray(partial.avoid)) next.avoid = partial.avoid
        dietAiRecommend.value = next
        dietAiStreamField.value = detectDietStreamField(dietStreamBuffer)
    }

    function applyDietRecommendPayload(payload) {
        if (!payload) return
        const prevAnalysis = dietAiRecommend.value.analysis
        const prevExercise = dietAiRecommend.value.exercise
        dietAiRecommend.value = {
            ...emptyDietAiRecommend(),
            ...payload,
            avoid: Array.isArray(payload.avoid) ? payload.avoid : [],
            analysis: Array.isArray(payload.analysis) && payload.analysis.length
                ? payload.analysis
                : (Array.isArray(prevAnalysis) ? prevAnalysis : []),
            exercise: (payload.exercise && typeof payload.exercise === 'object')
                ? payload.exercise
                : (prevExercise || null)
        }
    }

    function resolveDietDonePayload(payload) {
        if (!payload) return payload
        if (payload.source !== 'rule' || !dietStreamBuffer) return payload

        const streamed = parsePartialDietPlainText(dietStreamBuffer)
        if (!streamed.breakfast) return payload

        return {
            ...emptyDietAiRecommend(),
            ...payload,
            breakfast: streamed.breakfast,
            lunch: streamed.lunch || payload.lunch || '',
            dinner: streamed.dinner || payload.dinner || '',
            tips: streamed.tips || payload.tips || '',
            avoid: (Array.isArray(streamed.avoid) && streamed.avoid.length) ? streamed.avoid : (payload.avoid || []),
            source: 'ai',
            disclaimer: 'AI 建议供参考，仍请结合医嘱与血糖监测。'
        }
    }

    function onDietAiStreamEvent(event, payload) {
        if (event === 'analysis') {
            if (Array.isArray(payload?.analysis)) {
                dietAiRecommend.value = { ...dietAiRecommend.value, analysis: payload.analysis }
            }
        } else if (event === 'exercise') {
            if (payload?.exercise && typeof payload.exercise === 'object') {
                dietAiRecommend.value = { ...dietAiRecommend.value, exercise: payload.exercise }
            }
        } else if (event === 'delta') {
            dietAiStreaming.value = true
            if (payload.buffer != null) {
                dietStreamBuffer = payload.buffer
            } else {
                dietStreamBuffer += payload.text || ''
            }
            mergePartialDietFromStream()
        } else if (event === 'done') {
            applyDietRecommendPayload(resolveDietDonePayload(payload))
            dietStreamBuffer = ''
            dietAiStreamField.value = ''
        } else if (event === 'error') {
            showUserToast(formatUserMessage(payload?.message, '饮食建议加载失败'))
        }
    }

    async function fetchDietAiRecommendFallback(refresh) {
        const res = await proxy.apiUrl({
            url: '/api/tcm/dailyDietAiRecommend',
            method: 'GET',
            timeout: 35000,
            data: {
                diagnosis_id: diagnosisId.value,
                refresh: refresh ? 1 : 0,
                ...(refresh ? { _t: Date.now() } : {})
            }
        }, false)
        if (res?.code === 1 && res.data) {
            applyDietRecommendPayload(res.data)
        } else if (res?.msg) {
            showUserToast(res.msg)
        }
    }

    async function fetchDietAiRecommend(refresh = false) {
        if (!diagnosisId.value || dietAiLoading.value) return
        dietAiLoading.value = true
        dietAiStreaming.value = false
        dietAiReplacing.value = !!refresh
        dietStreamBuffer = ''
        dietAiStreamField.value = ''
        if (refresh) {
            applyDietRecommendPayload(emptyDietAiRecommend())
        }
        try {
            await requestAiStream({
                baseUrl: proxy.$url,
                url: '/api/tcm/dailyDietAiRecommendStream',
                method: 'GET',
                data: {
                    diagnosis_id: diagnosisId.value,
                    refresh: refresh ? 1 : 0,
                    ...(refresh ? { _t: Date.now() } : {})
                },
                onEvent: onDietAiStreamEvent,
                fallback: () => fetchDietAiRecommendFallback(refresh)
            })
        } catch (e) {
            try {
                await fetchDietAiRecommendFallback(refresh)
            } catch (e2) {
                showUserToast('饮食建议加载失败')
            }
        } finally {
            dietAiLoading.value = false
            dietAiStreaming.value = false
            dietAiReplacing.value = false
            dietAiStreamField.value = ''
        }
    }

    function refreshDietAiRecommend() {
        if (dietAiLoading.value) return
        fetchDietAiRecommend(true)
    }

    async function askDietAiFoodFallback(q) {
        const res = await proxy.apiUrl({
            url: '/api/tcm/dailyDietAiAsk',
            method: 'POST',
            timeout: 35000,
            data: {
                diagnosis_id: diagnosisId.value,
                question: q
            }
        }, false)
        if (res?.code === 1 && res.data) {
            dietAiAskResult.value = {
                advice: res.data.advice || '',
                level: res.data.level || '',
                level_label: res.data.level_label || '',
                portion: res.data.portion || '',
                food: res.data.food || q
            }
        } else {
            showUserToast(formatUserMessage(res?.msg, '咨询失败'))
        }
    }

    async function askDietAiFood() {
        const q = String(dietAiAskText.value || '').trim()
        if (!q) {
            showUserToast('请输入想咨询的食物')
            return
        }
        if (!diagnosisId.value) return
        dietAiAsking.value = true
        dietAiAskResult.value = { advice: '', level: '', level_label: '', portion: '', food: '' }
        try {
            await requestAiStream({
                baseUrl: proxy.$url,
                url: '/api/tcm/dailyDietAiAskStream',
                method: 'POST',
                data: {
                    diagnosis_id: diagnosisId.value,
                    question: q
                },
                onEvent: (event, payload) => {
                    if (event === 'start' && !dietAiAskResult.value.advice) {
                        dietAiAskResult.value = { ...dietAiAskResult.value, advice: payload.message || '正在想…' }
                    } else if (event === 'delta') {
                        dietAiAskResult.value = {
                            ...dietAiAskResult.value,
                            advice: payload.advice || dietAiAskResult.value.advice
                        }
                    } else if (event === 'done') {
                        dietAiAskResult.value = {
                            advice: payload.advice || '',
                            level: payload.level || '',
                            level_label: payload.level_label || '',
                            portion: payload.portion || '',
                            food: payload.food || q
                        }
                    } else if (event === 'error') {
                        showUserToast(formatUserMessage(payload?.message, '咨询失败'))
                    }
                },
                fallback: () => askDietAiFoodFallback(q)
            })
        } catch (e) {
            try {
                await askDietAiFoodFallback(q)
            } catch (e2) {
                showUserToast('网络异常，请稍后再试')
            }
        } finally {
            dietAiAsking.value = false
        }
    }

    function onDietAiAskInput(e) {
        dietAiAskText.value = e?.detail?.value ?? ''
    }

    function saveDietPrefillToStorage() {
        const r = dietAiRecommend.value
        if (!r.breakfast) return
        try {
            uni.setStorageSync(DIET_AI_PREFILL_KEY, {
                breakfast: r.breakfast,
                lunch: r.lunch,
                dinner: r.dinner,
                tips: r.tips || ''
            })
        } catch (e) {}
    }

    function goMoreDietForm(withPrefill = false) {
        if (withPrefill) saveDietPrefillToStorage()
        uni.navigateTo({ url: '/tongji/pages/more?openDiet=1' })
    }

    async function applyDietAiToForm() {
        if (!dietAiRecommend.value.breakfast) {
            await fetchDietAiRecommend(false)
        }
        goMoreDietForm(true)
    }

    function openDietForm() {
        goMoreDietForm(false)
    }

    return {
        dietAiRecommend,
        dietAiLoading,
        dietAiStreaming,
        dietAiReplacing,
        dietAiStreamField,
        dietAiAskText,
        dietAiAsking,
        dietAiAskResult,
        hasDietAiMealContent,
        fetchDietAiRecommend,
        refreshDietAiRecommend,
        askDietAiFood,
        onDietAiAskInput,
        applyDietAiToForm,
        openDietForm
    }
}

/** more 页打开饮食表单时读取并清除预填 */
export function consumeDietAiPrefill() {
    try {
        const data = uni.getStorageSync(DIET_AI_PREFILL_KEY)
        uni.removeStorageSync(DIET_AI_PREFILL_KEY)
        if (data && typeof data === 'object' && data.breakfast) return data
    } catch (e) {}
    return null
}