import type { Account } from './account.ts'

export type MutationMode = { execute: boolean; reason: string }

/** Writes preview by default: only `confirm: true` without `dryRun: true` executes. */
export function mutationMode(input: { dryRun?: boolean; confirm?: boolean }): MutationMode {
	if (input.dryRun === true) return { execute: false, reason: input.confirm ? 'dryRun: true wins over confirm: true' : 'dryRun: true' }
	if (input.confirm === true) return { execute: true, reason: 'confirm: true' }
	return { execute: false, reason: 'no confirm: true (preview by default)' }
}

export function echo(a: Account, action: string, target: string, mode: MutationMode) {
	return { mode: mode.execute ? 'write' : 'dry-run', action, account: a.account, secretName: a.secretName, target }
}

export function preview(a: Account, action: string, target: string, mode: MutationMode, request: Record<string, unknown>, extra: Record<string, unknown> = {}) {
	return {
		dryRun: true,
		executed: false,
		echo: echo(a, action, target, mode),
		reason: mode.reason,
		request,
		...extra,
		next: 'Nothing was sent to Granola. Show this preview to the user; re-run the same call with confirm: true (and without dryRun) only if they asked for this exact change.',
	}
}

const PRIVATE_HOST =
	/^(localhost|.*\.localhost|.*\.local|.*\.internal|127\.\d+\.\d+\.\d+|10\.\d+\.\d+\.\d+|192\.168\.\d+\.\d+|172\.(1[6-9]|2\d|3[01])\.\d+\.\d+|169\.254\.\d+\.\d+|0\.0\.0\.0|\[?::1\]?|\[?f[cd][0-9a-f]{2}:.*)$/i

/** Granola only accepts public HTTPS webhook URLs; refuse obvious mistakes before any request. */
export function checkWebhookUrl(raw: string): string {
	let u: URL
	try {
		u = new URL(raw)
	} catch {
		throw new Error(`Webhook url "${raw}" is not a valid URL.`)
	}
	if (u.protocol !== 'https:') throw new Error('Webhook url must use https:// (Granola rejects other schemes).')
	if (PRIVATE_HOST.test(u.hostname)) throw new Error(`Webhook url host "${u.hostname}" is private/local; Granola only delivers to publicly reachable HTTPS URLs.`)
	if (u.username || u.password) throw new Error('Webhook url must not embed credentials.')
	return u.toString()
}