// @ts-check

import Configuration from "../Configuration"
import html from "./html"
import ITemplate from "./ITemplate"
import sanitizeText from "./sanitizeText"

/**
 * @typedef {import("../element/LinkElement").default} LinkElement
 * @typedef {import("../element/LinkMessageElement").default} LinkMessageElement
 */

export default class LinkTemplate extends ITemplate {

    /**
     * Returns a function performing the inverse multiplication y = a / x + q. The value of a and q are calculated using
     * the derivative of that function y' = -a / x^2 at the point p (x = p[0] and y = p[1]). This means
     * y'(p[0]) = m => -a / p[0]^2 = m => a = -m * p[0]^2. Now, in order to determine q we can use the starting
     * function: p[1] = a / p[0] + q => q = p[1] - a / p[0]
     * @param {Number} m slope
     * @param {Number[]} p reference point
     * @returns Maximum value
     */
    static decreasingValue(m, p) {
        const a = -m * p[0] ** 2
        const q = p[1] - a / p[0]
        return x => a / x + q
    }

    /**
     * Returns a function performing a clamped line passing through two points. It is clamped after and before the
     * points. It is easier explained with an example.
     *            b ______
     *             /
     *            /
     *           /
     *          /
     *         /
     *  ______/ a
     */
    static clampedLine(a, b) {
        if (a[0] > b[0]) {
            const temp = a
            a = b
            b = temp
        }
        const m = (b[1] - a[1]) / (b[0] - a[0])
        const q = a[1] - m * a[0]
        return x => x < a[0]
            ? a[1]
            : x > b[0]
                ? b[1]
                : m * x + q
    }

    static c1DecreasingValue = LinkTemplate.decreasingValue(-0.1, [100, 15])

    static c2DecreasingValue = LinkTemplate.decreasingValue(-0.06, [500, 130])

    static c2Clamped = LinkTemplate.clampedLine([0, 100], [200, 30])

    /**
     * @param {LinkElement} link
     */
    render(link) {
        const uniqueId = "ueb-id-" + Math.floor(Math.random() * 1E12)
        return html`
            <svg version="1.2" baseProfile="tiny" width="100%" height="100%" viewBox="0 0 100 100" preserveAspectRatio="none">
                <g>
                    <path id="${uniqueId}" fill="none" vector-effect="non-scaling-stroke" />
                    <use href="#${uniqueId}" pointer-events="stroke" stroke-width="10" />
                </g>
            </svg>
        `
    }

    /**
     * @param {LinkElement} link
     */
    setup(link) {
        super.setup(link)
        if (link.linkMessageElement) {
            link.appendChild(link.linkMessageElement)
        }
        link.classList.add("ueb-positioned")
        link.pathElement = link.querySelector("path")
        const referencePin = link.sourcePin ?? link.destinationPin
        if (referencePin) {
            link.style.setProperty("--ueb-pin-color", referencePin.getColor())
        }
        this.applyPins(link)
        if (link.sourcePin && link.destinationPin) {
            this.applyFullLocation(link)
        }
    }

    /**
     * @param {LinkElement} link
     */
    applyPins(link) {
        if (link.sourcePin) {
            link.dataset.source = link.sourcePin.GetPinId().toString()
        }
        if (link.destinationPin) {
            link.dataset.destination = link.destinationPin.GetPinId().toString()
        }
    }

    /**
     * @param {LinkElement} link
     */
    applyStartDragging(link) {
        link.blueprint.dataset.creatingLink = "true"
        link.classList.add("ueb-link-dragging")
    }

    /**
     * @param {LinkElement} link
     */
    applyFinishDragging(link) {
        link.blueprint.dataset.creatingLink = "false"
        link.classList.remove("ueb-link-dragging")
    }

    /**
     * @param {LinkElement} link
     */
    applySourceLocation(link) {
        link.style.setProperty("--ueb-from-input", link.originatesFromInput ? "1" : "0")
        link.style.setProperty("--ueb-from-x", sanitizeText(link.sourceLocation[0]))
        link.style.setProperty("--ueb-from-y", sanitizeText(link.sourceLocation[1]))
    }

    /**
     * @param {LinkElement} link
     */
    applyFullLocation(link) {
        const dx = Math.max(Math.abs(link.sourceLocation[0] - link.destinationLocation[0]), 1)
        const width = Math.max(dx, Configuration.linkMinWidth)
        const height = Math.max(Math.abs(link.sourceLocation[1] - link.destinationLocation[1]), 1)
        const fillRatio = dx / width
        const aspectRatio = width / height
        const xInverted = link.originatesFromInput
            ? link.sourceLocation[0] < link.destinationLocation[0]
            : link.destinationLocation[0] < link.sourceLocation[0]
        let start = dx < width // If under minimum width
            ? (width - dx) / 2 // Start from half the empty space
            : 0 // Otherwise start from the beginning

        link.style.setProperty("--ueb-from-x", sanitizeText(link.sourceLocation[0]))
        link.style.setProperty("--ueb-from-y", sanitizeText(link.sourceLocation[1]))
        link.style.setProperty("--ueb-to-x", sanitizeText(link.destinationLocation[0]))
        link.style.setProperty("--ueb-to-y", sanitizeText(link.destinationLocation[1]))
        link.style.setProperty("margin-left", `-${start}px`)
        if (xInverted) {
            start += fillRatio * 100
        }
        link.style.setProperty("--ueb-start-percentage", `${start}%`)
        const c1
            = start
            + (xInverted
                ? LinkTemplate.c1DecreasingValue(width)
                : 10
            )
            * fillRatio
        let c2 = LinkTemplate.c2Clamped(xInverted ? -dx : dx) + start
        c2 = Math.min(c2, LinkTemplate.c2DecreasingValue(width))
        const d = Configuration.linkRightSVGPath(start, c1, c2)
        // TODO move to CSS when Firefox will support property d and css will have enough functions
        link.pathElement?.setAttribute("d", d)
    }

    /**
     * @param {LinkElement} link
     * @param {LinkMessageElement} linkMessage
     */
    applyLinkMessage(link, linkMessage) {
        link.querySelectorAll("ueb-link-message").forEach(element => element.remove())
        link.appendChild(linkMessage)
        link.linkMessageElement = linkMessage
    }
}