import {
	FieldContent,
	FieldContentType,
	isDateContent,
} from "@prismicio/types-internal/lib/content"
import type { Date as DateModel } from "@prismicio/types-internal/lib/customtypes"
import {
	DiffChange,
	DiffOperation,
} from "@prismicio/types-internal/lib/customtypes/diff"

import type { NestableMock, Patch } from "../../Mock"
import type { MockConfig } from "../../MockConfig"

export interface DateMockConfig extends MockConfig<DateModel["type"], Date> {
	start?: Date
	end?: Date
}

function formatDate(date: Date): string {
	const formatted = date.toISOString().split("T")[0]
	if (!formatted) throw new Error("Something happened during Date generation.")
	return formatted
}
function random(start = new Date(2012, 0, 1), end = new Date()): string {
	const genDate = new Date(
		start.getTime() + Math.random() * (end.getTime() - start.getTime()),
	)
	return formatDate(genDate)
}

export const DateMock: NestableMock<DateModel, FieldContent, DateMockConfig> = {
	generate(_def: DateModel, config?: DateMockConfig): FieldContent {
		const value = (() => {
			if (config?.value) return formatDate(config.value)
			if (config?.start && config?.end) return random(config.start, config.end)
			return random(new Date(2012, 0, 1), new Date())
		})()

		return {
			__TYPE__: FieldContentType,
			type: "Date",
			value,
		}
	},

	applyPatch(data: Patch):
		| {
				result: FieldContent | undefined
		  }
		| undefined {
		if (data.diff.op === DiffOperation.Removed) return { result: undefined }

		if (data.diff.value.type === "Date") {
			const patched = this.patch(
				data.diff,
				isDateContent(data.content) ? data.content : undefined,
				data.config?.type === "Date" ? data.config : undefined,
			)
			return { result: patched }
		}
		return
	},

	patch(
		diff: DiffChange<DateModel, DateModel>,
		_content: FieldContent,
		config?: DateMockConfig,
	): FieldContent | undefined {
		switch (diff.op) {
			case DiffOperation.Removed:
				return
			case DiffOperation.Updated:
			case DiffOperation.Added:
				return this.generate(diff.value, config)
		}
	},
}