import { intercomFetch, resolveIntercomAuth, type ResolvedIntercomAuth } from './auth.ts'
import { extractPageInfo } from './models.ts'
import type {
	DryRunResult,
	IntercomAuthInput,
	IntercomOperation,
	IntercomPageInfo,
	JsonRecord,
	MutationInput,
} from './types.ts'
import { requireString } from './types.ts'
import {
	INTERCOM_API_VERSION,
	inferOperationFromPath,
	intercomUrl,
	isMutatingMethod,
	isSearchPath,
	mutationPreview,
	nextStepForOperation,
	normalizeIntercomPath,
	permissionForOperation,
} from './setup.ts'

export class IntercomApiError extends Error {
	readonly status: number
	readonly operation: IntercomOperation
	readonly details: unknown
	readonly permission: string

	constructor(
		message: string,
		options: {
			status: number
			operation: IntercomOperation
			details: unknown
			permission: string
		},
	) {
		super(message)
		this.name = 'IntercomApiError'
		this.status = options.status
		this.operation = options.operation
		this.details = options.details
		this.permission = options.permission
	}
}

export type IntercomRequestInput = IntercomAuthInput &
	MutationInput & {
		path: string
		method?: string
		query?: JsonRecord
		body?: JsonRecord
		operation?: IntercomOperation
	}

export type IntercomResponse<T> = {
	data: T
	pageInfo: IntercomPageInfo
	status: number
}

function intercomErrorMessage(body: unknown): string | null {
	if (typeof body === 'string' && body.trim().length > 0) {
		return body.trim().slice(0, 400)
	}
	if (!body || typeof body !== 'object') return null
	const record = body as { errors?: unknown; message?: unknown; type?: unknown }
	if (Array.isArray(record.errors) && record.errors[0]) {
		const first = record.errors[0] as { message?: unknown; code?: unknown }
		if (typeof first.message === 'string' && first.message.length > 0) return first.message
		if (typeof first.code === 'string' && first.code.length > 0) return first.code
	}
	if (typeof record.message === 'string' && record.message.length > 0) return record.message
	return null
}

function looksLikeInsufficientPermission(status: number, body: unknown): boolean {
	if (status === 401 || status === 403) return true
	const message = (intercomErrorMessage(body) ?? '').toLowerCase()
	return (
		message.includes('unauthorized') ||
		message.includes('forbidden') ||
		message.includes('not authorized') ||
		message.includes('permission') ||
		message.includes('access token') ||
		message.includes('scope')
	)
}

export async function intercomRequest<T = unknown>(
	input: IntercomRequestInput,
): Promise<IntercomResponse<T> | DryRunResult> {
	const method = (input.method ?? 'GET').toUpperCase()
	const path = normalizeIntercomPath(requireString(input.path, 'path'))
	const operation = inferOperationFromPath(method, path, input.operation)
	const mutating = isMutatingMethod(method) && !isSearchPath(path)
	const url = intercomUrl(path, input.query, input)
	if (mutating) {
		const preview = mutationPreview(input, {
			method,
			path,
			url,
			body: input.body,
		})
		if (preview) return preview
	}
	const auth = await resolveIntercomAuth(input)
	return intercomRequestWithAuth<T>(auth, {
		method,
		path,
		query: input.query,
		body: input.body,
		operation,
		apiVersion: input.apiVersion,
	})
}

export async function intercomRequestWithAuth<T = unknown>(
	auth: ResolvedIntercomAuth,
	input: {
		method: string
		path: string
		query?: JsonRecord
		body?: JsonRecord
		operation: IntercomOperation
		apiVersion?: string
	},
): Promise<IntercomResponse<T>> {
	const url = intercomUrl(input.path, input.query, { apiBaseUrl: auth.apiBaseUrl })
	const headers = new Headers({
		Accept: 'application/json',
		'Intercom-Version': input.apiVersion ?? INTERCOM_API_VERSION,
		'User-Agent': 'kody-intercom/1.0',
	})
	const init: RequestInit = { method: input.method, headers }
	if (input.body !== undefined) {
		headers.set('Content-Type', 'application/json')
		init.body = JSON.stringify(input.body)
	}

	const response = await intercomFetch(auth, url, init)
	const text = await response.text()
	let parsed: unknown = text
	try {
		parsed = text ? JSON.parse(text) : null
	} catch {
		parsed = text
	}

	if (!response.ok || looksLikeInsufficientPermission(response.status, parsed)) {
		const permission = permissionForOperation(input.operation)
		const firstMessage =
			intercomErrorMessage(parsed) ||
			(typeof parsed === 'string' ? parsed.slice(0, 400) : response.statusText)
		throw new IntercomApiError(
			[
				`Intercom ${input.operation} failed (${response.status}): ${firstMessage}.`,
				`This call needs the "${permission}" permission.`,
				nextStepForOperation(input.operation, {
					authMode: auth.mode,
					integrationName: auth.integrationName,
					secretName: auth.secretName,
				}),
			].join(' '),
			{
				status: response.status,
				operation: input.operation,
				details: parsed,
				permission,
			},
		)
	}

	return {
		data: parsed as T,
		pageInfo: extractPageInfo(parsed),
		status: response.status,
	}
}

export { inferOperationFromPath, isMutatingMethod, isSearchPath }