import { Handlers } from '$fresh/server.ts'
import { DoneTask, DoneTaskModel } from '@homeman/models.ts'
import { db, kv } from '@homeman/db.ts'
import { z } from 'https://deno.land/x/zod@v3.21.4/mod.ts'

const DoneTaskPayload = DoneTaskModel.partial({ doneAt: true })
type DoneTaskPayload = z.infer<typeof DoneTaskPayload>

export const handler: Handlers<DoneTask | null> = {
	async POST(req, _ctx) {
		// a task is marked done
		let id: string | undefined
		if (req.headers.get('content-type')?.includes('json')) {
			id = DoneTaskPayload.parse(await req.json()).id
		} else {
			id = new URL(req.url).searchParams.get('id') || undefined
		}
		console.log('done task post:', id)
		if (!id) {
			return new Response(
				JSON.stringify({
					message: "can't complete task with id empty string",
				}),
				{ status: 400 },
			)
		}

		const newDoneTask: DoneTask = {
			id,
			doneAt: new Date(),
		}
		const res = await db.doneTasks.create({
			data: newDoneTask,
		})
		console.log('done task create result:', res)
		console.log(await db.doneTasks.findMany({}))

		await kv.set(['last_task_updated'], id)

		return new Response(JSON.stringify({ id }))
	},
	async DELETE(req, _ctx) {
		let id: string | undefined
		if (req.headers.get('content-type')?.includes('json')) {
			id = DoneTaskPayload.parse(await req.json()).id
		} else {
			id = new URL(req.url).searchParams.get('id') || undefined
		}
		console.log('done task delete:', id)
		if (!id) {
			return new Response(
				JSON.stringify({
					message: "can't uncomplete task with id empty string",
				}),
				{ status: 400 },
			)
		}
		if (!id) {
			return new Response(
				JSON.stringify({
					message: "can't complete task with id empty string",
				}),
				{ status: 400 },
			)
		}

		await db.doneTasks.deleteMany({
			where: {
				id,
			},
		})

		await kv.set(['last_task_updated'], id)

		return new Response(JSON.stringify({ id }))
	},
	async GET(req, ctx) {
		// TODO: json or query params
		const accept = req.headers.get('accept')
		if (accept === 'text/event-stream') {
			console.log('Request for task event stream')
			let skipFirst = true
			const stream = kv.watch([['last_task_updated']]).getReader()
			const body = new ReadableStream({
				async start(controller) {
					console.log(
						`Streaming task updates to ${JSON.stringify(ctx.remoteAddr)}...`,
					)
					while (true) {
						try {
							const entries = await stream.read()
							for (const entry of entries.value || []) {
								if (skipFirst) {
									skipFirst = false
									continue
								}
								if (typeof entry.value !== 'string') {
									continue
								}

								const task = await db.doneTask.findFirst({
									where: { id: entry.value },
								})
								const chunk = `data: ${
									JSON.stringify({
										id: entry.value,
										versionstamp: entry.versionstamp,
										value: task,
									})
								}\n\n`
								console.log('todo event chunk:', chunk)
								controller.enqueue(new TextEncoder().encode(chunk))
							}
							if (entries.done) {
								return
							}
						} catch (e) {
							console.error(`Error refreshing todo:`, e)
						}
					}
				},
				cancel() {
					stream.cancel()
					console.log(
						`Closed todo updates stream to ${JSON.stringify(ctx.remoteAddr)}`,
					)
				},
			})
			return new Response(body, {
				headers: {
					'content-type': 'text/event-stream',
				},
			})
		}
		return new Response(
			JSON.stringify({ done: await db.doneTasks.findMany({}) }),
		)
	},
}