import {
	FieldContent,
	FieldContentType,
	isRangeContent,
} from "@prismicio/types-internal/lib/content"
import type { Range } 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"

const DEFAULT_MIN = 0
const DEFAULT_MAX = 100
const DEFAULT_STEP = 1

function random(min: number, max: number, step: number): number {
	const rand = Math.floor(Math.random() * (max - min)) + min
	if (rand % step === 0) return rand

	const withStep = rand + (step - (rand % step)) // we ensure that it respects the increment step
	return Math.min(withStep, max) // if exceed max, just return max
}

export interface RangeMockConfig extends MockConfig<Range["type"], number> {
	min?: number
	max?: number
	step?: number
}

export const RangeMock: NestableMock<Range, FieldContent, RangeMockConfig> = {
	generate(def: Range, config?: RangeMockConfig): FieldContent {
		const min = (() => {
			if (def.config?.min) {
				return config?.min && config.min > def.config.min
					? config.min
					: def.config.min
			}
			return DEFAULT_MIN
		})()
		const max = (() => {
			if (def.config?.max) {
				return config?.max && config.max < def.config.max
					? config.max
					: def.config.max
			}
			return DEFAULT_MAX
		})()
		const step = (() => {
			if (def.config?.step) {
				return config?.step && config.step > def.config.step
					? config.step
					: def.config.step
			}
			return DEFAULT_STEP
		})()

		const value = (() => {
			if (config?.value) return config.value
			return random(min, max, step)
		})().toString()

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

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

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

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