/*
Copyright 2021 The Matrix.org Foundation C.I.C.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

const offColor = require("off-color").offColor;
const postcss = require("postcss");
const plugin = require("./css-compile-variables");
const derive = require("./color").derive;

async function run(input, output, opts = {}, assert) {
    let result = await postcss([plugin({ ...opts, derive })]).process(input, { from: undefined, });
    assert.strictEqual(
        result.css.replaceAll(/\s/g, ""),
        output.replaceAll(/\s/g, "")
    );
    assert.strictEqual(result.warnings().length, 0);
}

module.exports.tests = function tests() {
    return {
        "derived variables are resolved": async (assert) => {
            const inputCSS = `div {
                background-color: var(--foo-color--lighter-50);
            }`;
            const transformedColor = offColor("#ff0").lighten(0.5);
            const outputCSS =
                inputCSS +
                `
            :root {
                --foo-color: #ff0;
                --foo-color--lighter-50: ${transformedColor.hex()};
            }
            `;
            await run(
                inputCSS,
                outputCSS,
                { variables: { "foo-color": "#ff0" } },
                assert
            );
        },

        "derived variables work with alias": async (assert) => {
            const inputCSS = `div {
                background: var(--icon-color--darker-20);
                --my-alias: var(--icon-color--darker-20);
                color: var(--my-alias--lighter-15);
            }`;
            const colorDarker = offColor("#fff").darken(0.2).hex();
            const aliasLighter = offColor(colorDarker).lighten(0.15).hex();
            const outputCSS = `div {
                background: var(--icon-color--darker-20);
                --my-alias: var(--icon-color--darker-20);
                color: var(--my-alias--lighter-15);
            }
            :root {
                --icon-color: #fff;
                --icon-color--darker-20: ${colorDarker};
                --my-alias--lighter-15: ${aliasLighter};
            }
            `;
            await run(inputCSS, outputCSS, { variables: { "icon-color": "#fff" }, }, assert);
        },

        "derived variable throws if base not present in config": async (assert) => {
            const css = `:root {
                color: var(--icon-color--darker-20);
            }`;
            assert.rejects(async () => await postcss([plugin({ variables: {} })]).process(css, { from: undefined, }));
        },

        "multiple derived variable in single declaration is parsed correctly": async (assert) => {
            const inputCSS = `div {
                background-color: linear-gradient(var(--foo-color--lighter-50), var(--foo-color--darker-20));
            }`;
            const transformedColor1 = offColor("#ff0").lighten(0.5);
            const transformedColor2 = offColor("#ff0").darken(0.2);
            const outputCSS =
                inputCSS +
                `
            :root {
                --foo-color: #ff0;
                --foo-color--lighter-50: ${transformedColor1.hex()};
                --foo-color--darker-20: ${transformedColor2.hex()};
            }
            `;
            await run( inputCSS, outputCSS, { variables: { "foo-color": "#ff0" } }, assert);
        },
        "multiple aliased-derived variable in single declaration is parsed correctly": async (assert) => {
            const inputCSS = `div {
                --my-alias: var(--foo-color);
                background-color: linear-gradient(var(--my-alias--lighter-50), var(--my-alias--darker-20));
            }`;
            const transformedColor1 = offColor("#ff0").lighten(0.5);
            const transformedColor2 = offColor("#ff0").darken(0.2);
            const outputCSS =
                inputCSS +
                `
            :root {
                --foo-color: #ff0;
                --my-alias--lighter-50: ${transformedColor1.hex()};
                --my-alias--darker-20: ${transformedColor2.hex()};
            }
            `;
            await run( inputCSS, outputCSS, { variables: { "foo-color": "#ff0" } }, assert);
        }
    };
};