import { API_BASE_URL, ApiRequestError } from './auth'

export type CaseMode = 'training' | 'teaching'
export type CaseListSource = 'recommended' | 'specialty' | 'weak' | 'teaching' | 'teacher-task'
export type CaseTone = 'blue' | 'teal' | 'pink' | 'orange' | 'purple' | 'green'

export type ClinicalCase = {
	id: string
	title: string
	patientName: string
	gender: '男' | '女'
	age: number
	department: string
	departmentId?: number
	scene: string
	caseNo: string
	tone: CaseTone
	mode: CaseMode
	caseType?: string
	caseTypeDisplay?: string
	difficulty?: string
	difficultyScore?: number
	chiefComplaint?: string
	description?: string
	tags?: string
	competencyTags?: string[]
	estimatedMinutes?: number
	osceEnabled?: boolean
	myBestScore?: number | null
	myTrainCount?: number | null
	createdAt?: string
	source?: CaseListSource
}

export type CaseListQuery = {
	search?: string
	case_type?: string
	difficulty?: string
	department?: string | number
	page?: number
	page_size?: number
}

export type CaseListPage = {
	count: number
	next: string | null
	previous: string | null
	results: ClinicalCase[]
}

type QueryValue = string | number | boolean | null | undefined

type ServerCaseListPage = {
	count?: number
	next?: string | null
	previous?: string | null
	results?: ServerCaseRecord[]
}

type ServerCaseRecord = {
	id?: number | string
	title?: string
	case_type?: string
	case_type_display?: string
	difficulty?: string
	difficulty_score?: number
	department?: number
	department_name?: string
	chief_complaint?: string
	description?: string
	patient_age?: number
	patient_gender?: string
	tags?: string
	competency_tags?: string[]
	estimated_minutes?: number
	osce_enabled?: boolean
	created_at?: string
	my_best_score?: number | null
	my_train_count?: number | null
}

const CASE_LIST_PATHS: Record<CaseListSource, string> = {
	recommended: '/case/mobile/recommended/',
	specialty: '/case/mobile/specialty/',
	weak: '/case/mobile/weak/',
	teaching: '/case/mobile/teaching/',
	'teacher-task': '/case/mobile/teacher-task/'
}

const TONES: CaseTone[] = ['blue', 'teal', 'pink', 'orange', 'purple', 'green']

export async function fetchCaseList(source: CaseListSource = 'recommended', query: CaseListQuery = {}): Promise<ClinicalCase[]> {
	const page = await fetchCaseListPage(source, query)
	return page.results
}

export async function fetchCaseListPage(source: CaseListSource = 'recommended', query: CaseListQuery = {}): Promise<CaseListPage> {
	const path = CASE_LIST_PATHS[source] || CASE_LIST_PATHS.recommended
	const payload = await requestCaseList(path, query)
	const page = normalizeCaseListPage(payload, source)

	return page
}

export function readStoredClinicalCase() {
	const value = uni.getStorageSync('clinical-thinking-selected-case')
	if (value && typeof value === 'object') return value as ClinicalCase
	return null
}

export function resolveClinicalCaseId(caseItem?: ClinicalCase | null) {
	if (!caseItem) return 0

	const explicitId = Number(caseItem.id)
	if (Number.isInteger(explicitId) && explicitId > 0) return explicitId

	const caseNo = Number(caseItem.caseNo)
	if (Number.isInteger(caseNo) && caseNo > 0) return caseNo

	const matched = String(caseItem.id).match(/\d+/)
	const fallbackId = matched ? Number(matched[0]) : 0
	return Number.isInteger(fallbackId) && fallbackId > 0 ? fallbackId : 0
}

function requestCaseList(path: string, query: CaseListQuery): Promise<ServerCaseListPage> {
	return new Promise((resolve, reject) => {
		uni.request({
			url: `${API_BASE_URL}${withQuery(path, query)}`,
			method: 'GET',
			timeout: 10000,
			header: createAuthHeaders(),
			success: response => {
				if (response.statusCode >= 200 && response.statusCode < 300) {
					resolve(response.data as ServerCaseListPage)
					return
				}

				const payload = response.data as Record<string, unknown> | undefined
				const code = typeof payload?.code === 'string' ? payload.code : undefined
				reject(new ApiRequestError(readErrorMessage(response.data, `病例列表加载失败（${response.statusCode}）`), code, response.statusCode))
			},
			fail: error => {
				reject(new ApiRequestError(error.errMsg || '无法连接服务'))
			}
		})
	})
}

function normalizeCaseListPage(payload: ServerCaseListPage, source: CaseListSource): CaseListPage {
	const results = Array.isArray(payload.results) ? payload.results : []

	return {
		count: readNumber(payload.count, results.length),
		next: typeof payload.next === 'string' ? payload.next : null,
		previous: typeof payload.previous === 'string' ? payload.previous : null,
		results: results.map((item, index) => normalizeCaseRecord(item, source, index))
	}
}

function normalizeCaseRecord(item: ServerCaseRecord, source: CaseListSource, index: number): ClinicalCase {
	const id = readString(item.id, `case-${index + 1}`)
	const title = readString(item.title, '未命名病例')
	const gender = normalizeGender(item.patient_gender)
	const departmentName = readString(item.department_name, '未配置科室')
	const caseType = readString(item.case_type)
	const caseTypeDisplay = readString(item.case_type_display, caseType || '练习病例')
	const chiefComplaint = readString(item.chief_complaint, title)
	const mode = source === 'teaching' || caseType === 'teaching' ? 'teaching' : 'training'

	return {
		id,
		title,
		patientName: gender === '女' ? '患者女士' : '患者先生',
		gender,
		age: readNumber(item.patient_age, 0),
		department: departmentName,
		departmentId: readOptionalNumber(item.department),
		scene: caseTypeDisplay,
		caseNo: id,
		tone: TONES[index % TONES.length],
		mode,
		caseType,
		caseTypeDisplay,
		difficulty: readString(item.difficulty),
		difficultyScore: readOptionalNumber(item.difficulty_score),
		chiefComplaint,
		description: readString(item.description),
		tags: readString(item.tags),
		competencyTags: Array.isArray(item.competency_tags) ? item.competency_tags.map(String) : [],
		estimatedMinutes: readOptionalNumber(item.estimated_minutes),
		osceEnabled: Boolean(item.osce_enabled),
		myBestScore: typeof item.my_best_score === 'number' ? item.my_best_score : null,
		myTrainCount: typeof item.my_train_count === 'number' ? item.my_train_count : null,
		createdAt: readString(item.created_at),
		source
	}
}

function createAuthHeaders() {
	const headers: Record<string, string> = {
		'Content-Type': 'application/json',
		Accept: 'application/json'
	}
	const token = readAccessToken()
	if (token) headers.Authorization = `Bearer ${token}`
	return headers
}

function readAccessToken() {
	try {
		const token = uni.getStorageSync('clinical-thinking-access-token')
		return typeof token === 'string' ? token.trim() : ''
	} catch {
		return ''
	}
}

function withQuery(path: string, query: Record<string, QueryValue>) {
	const params = Object.entries(query)
		.filter(([, value]) => value !== undefined && value !== null && value !== '')
		.map(([key, value]) => `${encodeURIComponent(key)}=${encodeURIComponent(String(value))}`)
		.join('&')

	return params ? `${path}?${params}` : path
}

function readErrorMessage(data: unknown, fallback: string) {
	if (data && typeof data === 'object') {
		const payload = data as Record<string, unknown>
		const message = payload.message || payload.detail || payload.error
		if (typeof message === 'string' && message.trim()) return message
	}
	return fallback
}

function readString(value: unknown, fallback = '') {
	if (typeof value === 'string') return value.trim() || fallback
	if (typeof value === 'number') return String(value)
	return fallback
}

function readNumber(value: unknown, fallback = 0) {
	const numberValue = Number(value)
	return Number.isFinite(numberValue) ? numberValue : fallback
}

function readOptionalNumber(value: unknown) {
	const numberValue = Number(value)
	return Number.isFinite(numberValue) ? numberValue : undefined
}

function normalizeGender(value: unknown): '男' | '女' {
	if (value === 'female' || value === '女') return '女'
	return '男'
}