import { isConfirmed, isDryRun, normalizeProjectLocator, pickAuthInput, request } from '../core.ts'
import { asRecord, readOptionalBoolean, readOptionalString, slimMergeRequest } from '../shape.ts'

/**
 * Create a GitLab merge request.
 *
 * Pass `dryRun: true` to preview the request. Live creates require `confirm: true`.
 *
 * @example
 * import createGitlabMergeRequest from 'kody:@kody/gitlab/merge-requests/create'
 * const preview = await createGitlabMergeRequest({
 *   project: 'example-group/example-project',
 *   source_branch: 'feature/example',
 *   target_branch: 'main',
 *   title: 'Example merge request',
 *   dryRun: true,
 * })
 */
export default async function createGitlabMergeRequest(params: Record<string, unknown> = {}) {
	const auth = pickAuthInput(params)
	const { projectId, projectPath } = normalizeProjectLocator(params)
	const sourceBranch = readOptionalString(params.source_branch ?? params.sourceBranch)
	const targetBranch = readOptionalString(params.target_branch ?? params.targetBranch)
	const title = readOptionalString(params.title)
	if (!sourceBranch || !targetBranch || !title) {
		throw new Error('source_branch, target_branch, and title are required')
	}

	const body: Record<string, unknown> = {
		source_branch: sourceBranch,
		target_branch: targetBranch,
		title,
	}
	const description = readOptionalString(params.description)
	if (description) body.description = description
	const labels = readOptionalString(params.labels)
	if (labels) body.labels = labels
	const removeSourceBranch = readOptionalBoolean(
		params.remove_source_branch ?? params.removeSourceBranch,
	)
	if (removeSourceBranch !== undefined) body.remove_source_branch = removeSourceBranch
	const squash = readOptionalBoolean(params.squash)
	if (squash !== undefined) body.squash = squash

	if (isDryRun(params)) {
		return {
			dryRun: true,
			wouldCreate: true,
			projectPath,
			body,
			auth,
		}
	}

	if (!isConfirmed(params)) {
		throw new Error(
			`Creating a merge request in ${projectPath} requires dryRun: true (preview) or confirm: true (live write).`,
		)
	}

	const response = await request<Record<string, unknown>>({
		...auth,
		method: 'POST',
		path: `/projects/${projectId}/merge_requests`,
		body,
		throwOnError: true,
		confirm: true,
	})

	return {
		...slimMergeRequest(asRecord(response.data)),
		projectPath,
		auth: response.auth,
	}
}