import { FASTAPI_BASE_URL, authHeaders, readError, type ApiEnvelope, type ScoreType } from './session'
import type { EvaluationResult } from './assessment'

export type TeachingAnswer = {
	question_id: number | string
	selected_answer: string
}

export type TeachingCaseOption = {
	key: string
	value: string
	text: string
}

export type TeachingCaseQuestion = {
	id: number | string
	question: string
	options: TeachingCaseOption[]
	correctAnswer?: string
	analysis?: string
	note?: string
	videoTitle?: string
	videoDesc?: string
	videoUrl?: string
}

type TeachingEvaluationPayload = {
	case_id: number
	answers: TeachingAnswer[]
	score_type?: ScoreType
}

type TeachingCaseItemsResponse = {
	items?: unknown[]
	questions?: unknown[]
	results?: unknown[]
	list?: unknown[]
}

export async function fetchTeachingCaseItems(caseId: number) {
	const response = await fetch(`${FASTAPI_BASE_URL}/teaching/cases/${caseId}/items`, {
		method: 'GET',
		headers: authHeaders()
	})

	if (!response.ok) {
		throw new Error(await readError(response))
	}

	const result = (await response.json()) as ApiEnvelope<TeachingCaseItemsResponse | unknown[]>
	if (result.code !== 'OK' || !result.data) {
		throw new Error(result.message || '题目列表加载失败')
	}

	const rawItems = Array.isArray(result.data)
		? result.data
		: result.data.items || result.data.questions || result.data.results || result.data.list || []

	return rawItems.map(normalizeTeachingQuestion).filter((item): item is TeachingCaseQuestion => Boolean(item))
}

export async function generateTeachingEvaluation(payload: TeachingEvaluationPayload) {
	const response = await fetch(`${FASTAPI_BASE_URL}/teaching/evaluation`, {
		method: 'POST',
		headers: authHeaders(),
		body: JSON.stringify(payload)
	})

	if (!response.ok) {
		throw new Error(await readError(response))
	}

	const result = (await response.json()) as ApiEnvelope<EvaluationResult>
	if (result.code !== 'OK' || !result.data?.evaluation_id) {
		throw new Error(result.message || '教学评价生成失败')
	}

	return result.data
}

function normalizeTeachingQuestion(item: unknown) {
	if (!item || typeof item !== 'object') return null

	const source = item as Record<string, unknown>
	const video = readObject(source.video)
	const id = readId(source)
	const question = readString(source, ['question', 'title', 'stem', 'content', 'text'])
	const options = normalizeOptions(source.options || source.choices || source.answers)

	if (!id || !question || options.length === 0) return null

	return {
		id,
		question,
		options,
		correctAnswer: readString(source, ['correct_answer', 'correctAnswer', 'answer', 'right_answer']),
		analysis: readString(source, ['analysis', 'explanation', '解析']),
		note: readString(source, ['note', 'hint', 'comment']),
		videoTitle: readString(video, ['title', 'name']) || readString(source, ['video_title', 'videoTitle']),
		videoDesc: readString(video, ['description', 'desc']) || readString(source, ['video_desc', 'videoDesc', 'video_description']),
		videoUrl: readString(video, ['url']) || readString(source, ['video_url', 'videoUrl'])
	}
}

function readObject(value: unknown) {
	if (value && typeof value === 'object' && !Array.isArray(value)) return value as Record<string, unknown>
	return {}
}

function readId(source: Record<string, unknown>) {
	const value = source.question_id || source.id || source.item_id
	if (typeof value === 'number' || typeof value === 'string') return value
	return ''
}

function normalizeOptions(value: unknown): TeachingCaseOption[] {
	if (Array.isArray(value)) {
		return value.map((item, index) => normalizeOption(item, index)).filter((item): item is TeachingCaseOption => Boolean(item))
	}

	if (value && typeof value === 'object') {
		return Object.entries(value as Record<string, unknown>).map(([key, text]) => ({
			key,
			value: key,
			text: typeof text === 'string' ? text : String(text || '')
		})).filter(item => item.text)
	}

	return []
}

function normalizeOption(item: unknown, index: number) {
	const fallbackKey = String.fromCharCode(65 + index)
	if (typeof item === 'string') {
		return {
			key: fallbackKey,
			value: fallbackKey,
			text: item
		}
	}

	if (!item || typeof item !== 'object') return null

	const source = item as Record<string, unknown>
	const value = readString(source, ['value', 'key', 'option', 'option_key', 'id']) || fallbackKey
	const key = readString(source, ['key', 'option', 'option_key']) || value
	const text = readString(source, ['label', 'text', 'content', 'option_text', 'name']) || value

	return {
		key,
		value,
		text
	}
}

function readString(source: Record<string, unknown>, keys: string[]) {
	for (const key of keys) {
		const value = source[key]
		if (typeof value === 'string' && value.trim()) return value
		if (typeof value === 'number') return String(value)
	}
	return ''
}