import {
  ValueTypes,
  arrayToGlsl,
  colorToGlsl,
  expressionToGlsl,
  getValueType,
  isTypeUnique,
  numberToGlsl,
  stringToGlsl,
  uniformNameForVariable,
} from '../../../../../src/ol/style/expressions.js';

describe('ol/style/expressions', function () {
  describe('numberToGlsl', function () {
    it('does a simple transform when a fraction is present', function () {
      expect(numberToGlsl(1.3456)).to.eql('1.3456');
    });
    it('adds a fraction separator when missing', function () {
      expect(numberToGlsl(1)).to.eql('1.0');
      expect(numberToGlsl(2.0)).to.eql('2.0');
    });
  });

  describe('arrayToGlsl', function () {
    it('outputs numbers with dot separators', function () {
      expect(arrayToGlsl([1, 0, 3.45, 0.8888])).to.eql(
        'vec4(1.0, 0.0, 3.45, 0.8888)'
      );
      expect(arrayToGlsl([3, 4])).to.eql('vec2(3.0, 4.0)');
    });
    it('throws on invalid lengths', function () {
      let thrown = false;
      try {
        arrayToGlsl([3]);
      } catch (e) {
        thrown = true;
      }
      try {
        arrayToGlsl([3, 2, 1, 0, -1]);
      } catch (e) {
        thrown = true;
      }
      expect(thrown).to.be(true);
    });
  });

  describe('colorToGlsl', function () {
    it('normalizes color and outputs numbers with dot separators', function () {
      expect(colorToGlsl([100, 0, 255])).to.eql(
        'vec4(0.39215686274509803, 0.0, 1.0, 1.0)'
      );
      expect(colorToGlsl([100, 0, 255, 1])).to.eql(
        'vec4(0.39215686274509803, 0.0, 1.0, 1.0)'
      );
    });
    it('handles colors in string format', function () {
      expect(colorToGlsl('red')).to.eql('vec4(1.0, 0.0, 0.0, 1.0)');
      expect(colorToGlsl('#00ff99')).to.eql('vec4(0.0, 1.0, 0.6, 1.0)');
      expect(colorToGlsl('rgb(100, 0, 255)')).to.eql(
        'vec4(0.39215686274509803, 0.0, 1.0, 1.0)'
      );
      expect(colorToGlsl('rgba(100, 0, 255, 0.3)')).to.eql(
        'vec4(0.39215686274509803, 0.0, 1.0, 0.3)'
      );
    });
  });

  describe('stringToGlsl', function () {
    let context;
    beforeEach(function () {
      context = {
        stringLiteralsMap: {},
        functions: {},
      };
    });

    it('maps input string to stable numbers', function () {
      expect(stringToGlsl(context, 'abcd')).to.eql('0.0');
      expect(stringToGlsl(context, 'defg')).to.eql('1.0');
      expect(stringToGlsl(context, 'hijk')).to.eql('2.0');
      expect(stringToGlsl(context, 'abcd')).to.eql('0.0');
      expect(stringToGlsl(context, 'def')).to.eql('3.0');
    });
  });

  describe('isTypeUnique', function () {
    it('return true if only one value type', function () {
      expect(isTypeUnique(ValueTypes.NUMBER)).to.eql(true);
      expect(isTypeUnique(ValueTypes.STRING)).to.eql(true);
      expect(isTypeUnique(ValueTypes.COLOR)).to.eql(true);
    });
    it('return false if several value types', function () {
      expect(isTypeUnique(ValueTypes.NUMBER | ValueTypes.COLOR)).to.eql(false);
      expect(isTypeUnique(ValueTypes.ANY)).to.eql(false);
    });
    it('return false if no value type', function () {
      expect(isTypeUnique(ValueTypes.NUMBER & ValueTypes.COLOR)).to.eql(false);
    });
  });

  describe('getValueType', function () {
    it('correctly analyzes a literal value', function () {
      expect(getValueType(1234)).to.eql(ValueTypes.NUMBER);
      expect(getValueType([1, 2, 3, 4])).to.eql(
        ValueTypes.COLOR | ValueTypes.NUMBER_ARRAY
      );
      expect(getValueType([1, 2, 3])).to.eql(
        ValueTypes.COLOR | ValueTypes.NUMBER_ARRAY
      );
      expect(getValueType([1, 2])).to.eql(ValueTypes.NUMBER_ARRAY);
      expect(getValueType([1, 2, 3, 4, 5])).to.eql(ValueTypes.NUMBER_ARRAY);
      expect(getValueType('yellow')).to.eql(
        ValueTypes.COLOR | ValueTypes.STRING
      );
      expect(getValueType('#113366')).to.eql(
        ValueTypes.COLOR | ValueTypes.STRING
      );
      expect(getValueType('rgba(252,171,48,0.62)')).to.eql(
        ValueTypes.COLOR | ValueTypes.STRING
      );
      expect(getValueType('abcd')).to.eql(ValueTypes.STRING);
      expect(getValueType(true)).to.eql(ValueTypes.BOOLEAN);
    });

    it('throws on an unsupported type (object)', function (done) {
      try {
        getValueType(new Object());
      } catch (e) {
        done();
      }
      done(true);
    });

    it('throws on an unsupported type (mixed array)', function (done) {
      try {
        getValueType([1, true, 'aa']);
      } catch (e) {
        done();
      }
      done(true);
    });

    it('correctly analyzes operator return types', function () {
      expect(getValueType(['get', 'myAttr'])).to.eql(ValueTypes.ANY);
      expect(getValueType(['var', 'myValue'])).to.eql(ValueTypes.ANY);
      expect(getValueType(['time'])).to.eql(ValueTypes.NUMBER);
      expect(getValueType(['zoom'])).to.eql(ValueTypes.NUMBER);
      expect(getValueType(['resolution'])).to.eql(ValueTypes.NUMBER);
      expect(getValueType(['+', ['get', 'size'], 12])).to.eql(
        ValueTypes.NUMBER
      );
      expect(getValueType(['-', ['get', 'size'], 12])).to.eql(
        ValueTypes.NUMBER
      );
      expect(getValueType(['/', ['get', 'size'], 12])).to.eql(
        ValueTypes.NUMBER
      );
      expect(getValueType(['*', ['get', 'size'], 12])).to.eql(
        ValueTypes.NUMBER
      );
      expect(
        getValueType(['clamp', ['get', 'attr2'], ['get', 'attr3'], 20])
      ).to.eql(ValueTypes.NUMBER);
      expect(getValueType(['^', 10, 2])).to.eql(ValueTypes.NUMBER);
      expect(getValueType(['%', ['time'], 10])).to.eql(ValueTypes.NUMBER);
      expect(getValueType(['>', 10, ['get', 'attr4']])).to.eql(
        ValueTypes.BOOLEAN
      );
      expect(getValueType(['>=', 10, ['get', 'attr4']])).to.eql(
        ValueTypes.BOOLEAN
      );
      expect(getValueType(['<', 10, ['get', 'attr4']])).to.eql(
        ValueTypes.BOOLEAN
      );
      expect(getValueType(['<=', 10, ['get', 'attr4']])).to.eql(
        ValueTypes.BOOLEAN
      );
      expect(getValueType(['==', 10, ['get', 'attr4']])).to.eql(
        ValueTypes.BOOLEAN
      );
      expect(getValueType(['!=', 10, ['get', 'attr4']])).to.eql(
        ValueTypes.BOOLEAN
      );
      expect(getValueType(['all', true, ['get', 'attr4']])).to.eql(
        ValueTypes.BOOLEAN
      );
      expect(getValueType(['any', true, ['get', 'attr4']])).to.eql(
        ValueTypes.BOOLEAN
      );
      expect(getValueType(['between', ['get', 'attr4'], -4.0, 5.0])).to.eql(
        ValueTypes.BOOLEAN
      );
      expect(getValueType(['!', ['get', 'attr4']])).to.eql(ValueTypes.BOOLEAN);
      expect(getValueType(['array', ['get', 'attr4'], 1, 2, 3])).to.eql(
        ValueTypes.NUMBER_ARRAY
      );
      expect(getValueType(['color', ['get', 'attr4'], 1, 2])).to.eql(
        ValueTypes.COLOR
      );
    });
  });

  describe('expressionToGlsl', function () {
    let context;

    beforeEach(function () {
      context = {
        variables: [],
        attributes: [],
        stringLiteralsMap: {},
        functions: {},
      };
    });

    it('correctly converts expressions to GLSL', function () {
      expect(expressionToGlsl(context, ['get', 'myAttr'])).to.eql('a_myAttr');
      expect(expressionToGlsl(context, ['var', 'myValue'])).to.eql(
        uniformNameForVariable('myValue')
      );
      expect(expressionToGlsl(context, ['time'])).to.eql('u_time');
      expect(expressionToGlsl(context, ['zoom'])).to.eql('u_zoom');
      expect(expressionToGlsl(context, ['resolution'])).to.eql('u_resolution');
      expect(
        expressionToGlsl(context, ['+', ['*', ['get', 'size'], 0.001], 12])
      ).to.eql('((a_size * 0.001) + 12.0)');
      expect(
        expressionToGlsl(context, ['/', ['-', ['get', 'size'], 20], 100])
      ).to.eql('((a_size - 20.0) / 100.0)');
      expect(
        expressionToGlsl(context, [
          'clamp',
          ['get', 'attr2'],
          ['get', 'attr3'],
          20,
        ])
      ).to.eql('clamp(a_attr2, a_attr3, 20.0)');
      expect(expressionToGlsl(context, ['^', ['%', ['time'], 10], 2])).to.eql(
        'pow(mod(u_time, 10.0), 2.0)'
      );
      expect(
        expressionToGlsl(context, [
          'abs',
          ['-', ['get', 'attr3'], ['get', 'attr2']],
        ])
      ).to.eql('abs((a_attr3 - a_attr2))');
      expect(expressionToGlsl(context, ['sin', 1])).to.eql('sin(1.0)');
      expect(expressionToGlsl(context, ['cos', 1])).to.eql('cos(1.0)');
      expect(expressionToGlsl(context, ['atan', 1])).to.eql('atan(1.0)');
      expect(expressionToGlsl(context, ['atan', 1, 0.5])).to.eql(
        'atan(1.0, 0.5)'
      );
      expect(expressionToGlsl(context, ['>', 10, ['get', 'attr4']])).to.eql(
        '(10.0 > a_attr4)'
      );
      expect(expressionToGlsl(context, ['>=', 10, ['get', 'attr4']])).to.eql(
        '(10.0 >= a_attr4)'
      );
      expect(expressionToGlsl(context, ['<', 10, ['get', 'attr4']])).to.eql(
        '(10.0 < a_attr4)'
      );
      expect(expressionToGlsl(context, ['<=', 10, ['get', 'attr4']])).to.eql(
        '(10.0 <= a_attr4)'
      );
      expect(expressionToGlsl(context, ['==', 10, ['get', 'attr4']])).to.eql(
        '(10.0 == a_attr4)'
      );
      expect(expressionToGlsl(context, ['==', 'red', ['get', 'attr4']])).to.eql(
        `(${stringToGlsl(context, 'red')} == a_attr4)`
      );
      expect(expressionToGlsl(context, ['!=', 10, ['get', 'attr4']])).to.eql(
        '(10.0 != a_attr4)'
      );
      expect(expressionToGlsl(context, ['all', true, ['get', 'attr4']])).to.eql(
        '(true && a_attr4)'
      );
      expect(expressionToGlsl(context, ['any', true, ['get', 'attr4']])).to.eql(
        '(true || a_attr4)'
      );
      expect(
        expressionToGlsl(context, ['any', true, ['get', 'attr4'], true])
      ).to.eql('(true || a_attr4 || true)');
      expect(
        expressionToGlsl(context, ['between', ['get', 'attr4'], -4.0, 5.0])
      ).to.eql('(a_attr4 >= -4.0 && a_attr4 <= 5.0)');
      expect(expressionToGlsl(context, ['!', ['get', 'attr4']])).to.eql(
        '(!a_attr4)'
      );
      expect(
        expressionToGlsl(context, ['array', ['get', 'attr4'], 1, 2, 3])
      ).to.eql('vec4(a_attr4, 1.0, 2.0, 3.0)');
      expect(
        expressionToGlsl(context, ['color', ['get', 'attr4'], 1, 2, 0.5])
      ).to.eql('vec4(a_attr4 / 255.0, 1.0 / 255.0, 2.0 / 255.0, 0.5)');
      expect(expressionToGlsl(context, ['band', 1])).to.eql(
        'getBandValue(1.0, 0.0, 0.0)'
      );
      expect(expressionToGlsl(context, ['band', 1, -1, 2])).to.eql(
        'getBandValue(1.0, -1.0, 2.0)'
      );
    });

    it('throws if the value does not match the type', function () {
      const call = function () {
        expressionToGlsl(context, '42', ValueTypes.NUMBER);
      };
      expect(call).to.throwException(/Unexpected expression/);
    });

    it('correctly adapts output for fragment shaders', function () {
      context.inFragmentShader = true;
      expect(expressionToGlsl(context, ['get', 'myAttr'])).to.eql('v_myAttr');
    });

    it('correctly adapts output for fragment shaders', function () {
      expressionToGlsl(context, ['get', 'myAttr']);
      expressionToGlsl(context, ['var', 'myVar']);
      expressionToGlsl(context, [
        'clamp',
        ['get', 'attr2'],
        ['get', 'attr2'],
        ['get', 'myAttr'],
      ]);
      expressionToGlsl(context, ['*', ['get', 'attr2'], ['var', 'myVar']]);
      expressionToGlsl(context, ['*', ['get', 'attr3'], ['var', 'myVar2']]);
      expect(context.attributes).to.eql(['myAttr', 'attr2', 'attr3']);
      expect(context.variables).to.eql(['myVar', 'myVar2']);
    });

    it('gives precedence to the string type unless asked otherwise', function () {
      expect(expressionToGlsl(context, 'lightgreen')).to.eql('0.0');
      expect(expressionToGlsl(context, 'lightgreen', ValueTypes.COLOR)).to.eql(
        'vec4(0.5647058823529412, 0.9333333333333333, 0.5647058823529412, 1.0)'
      );
    });

    it('throws on unsupported types for operators', function () {
      let thrown = false;
      try {
        expressionToGlsl(context, ['var', 1234]);
      } catch (e) {
        thrown = true;
      }
      expect(thrown).to.be(true);

      thrown = false;
      try {
        expressionToGlsl(context, ['any', ['var', 'aa'], 10]);
      } catch (e) {
        thrown = true;
      }
      expect(thrown).to.be(true);

      thrown = false;
      try {
        expressionToGlsl(context, ['all', ['var', 'aa'], 10]);
      } catch (e) {
        thrown = true;
      }
      expect(thrown).to.be(true);

      thrown = false;
      try {
        expressionToGlsl(context, ['<', 0, 'aa']);
      } catch (e) {
        thrown = true;
      }
      expect(thrown).to.be(true);

      thrown = false;
      try {
        expressionToGlsl(context, ['+', true, ['get', 'attr']]);
      } catch (e) {
        thrown = true;
      }
      expect(thrown).to.be(true);

      thrown = false;
      try {
        expressionToGlsl(context, ['color', 1, 2, 'red']);
      } catch (e) {
        thrown = true;
      }
      expect(thrown).to.be(true);

      thrown = false;
      try {
        expressionToGlsl(context, ['array', 1, '2', 3]);
      } catch (e) {
        thrown = true;
      }
      expect(thrown).to.be(true);
    });

    it('throws with the wrong number of arguments', function () {
      let thrown = false;
      try {
        expressionToGlsl(context, ['var', 1234, 456]);
      } catch (e) {
        thrown = true;
      }
      expect(thrown).to.be(true);

      thrown = false;
      try {
        expressionToGlsl(context, ['all', ['var', true], ['get', true], true]);
      } catch (e) {
        thrown = true;
      }
      expect(thrown).to.be(true);

      thrown = false;
      try {
        expressionToGlsl(context, ['any', ['var', true]]);
      } catch (e) {
        thrown = true;
      }
      expect(thrown).to.be(true);

      thrown = false;
      try {
        expressionToGlsl(context, ['<', 4]);
      } catch (e) {
        thrown = true;
      }
      expect(thrown).to.be(true);

      thrown = false;
      try {
        expressionToGlsl(context, ['+']);
      } catch (e) {
        thrown = true;
      }
      expect(thrown).to.be(true);

      thrown = false;
      try {
        expressionToGlsl(context, ['array', 1]);
      } catch (e) {
        thrown = true;
      }
      expect(thrown).to.be(true);

      thrown = false;
      try {
        expressionToGlsl(context, ['color', 1, 2, 3, 4, 5]);
      } catch (e) {
        thrown = true;
      }
      expect(thrown).to.be(true);
    });

    it('throws on invalid expressions', function () {
      let thrown = false;
      try {
        expressionToGlsl(context, null);
      } catch (e) {
        thrown = true;
      }
      expect(thrown).to.be(true);
    });
  });

  describe('case operator', function () {
    let context;

    beforeEach(function () {
      context = {
        variables: [],
        attributes: [],
        stringLiteralsMap: {},
        functions: {},
      };
    });

    it('correctly guesses the output type', function () {
      expect(getValueType(['case', true, 0, false, [3, 4, 5], 'green'])).to.eql(
        ValueTypes.NONE
      );
      expect(getValueType(['case', true, 0, false, 1, 2])).to.eql(
        ValueTypes.NUMBER
      );
      expect(
        getValueType([
          'case',
          true,
          [0, 0, 0],
          true,
          [1, 2, 3],
          ['get', 'attr'],
          [4, 5, 6, 7],
          [8, 9, 0],
        ])
      ).to.eql(ValueTypes.COLOR | ValueTypes.NUMBER_ARRAY);
      expect(
        getValueType([
          'case',
          true,
          'red',
          true,
          'yellow',
          ['get', 'attr'],
          'green',
          'white',
        ])
      ).to.eql(ValueTypes.COLOR | ValueTypes.STRING);
      expect(
        getValueType(['case', true, [0, 0], false, [1, 1], [2, 2]])
      ).to.eql(ValueTypes.NUMBER_ARRAY);
    });

    it('throws if no single output type could be inferred', function () {
      let thrown = false;
      try {
        expressionToGlsl(
          context,
          ['case', false, 'red', true, 'yellow', 'green'],
          ValueTypes.COLOR
        );
      } catch (e) {
        thrown = true;
      }
      expect(thrown).to.be(false);

      try {
        expressionToGlsl(context, [
          'case',
          true,
          'red',
          true,
          'yellow',
          'green',
        ]);
      } catch (e) {
        thrown = true;
      }
      expect(thrown).to.be(true);

      thrown = false;
      try {
        expressionToGlsl(
          context,
          ['case', true, 'red', false, 'yellow', 'green'],
          ValueTypes.NUMBER
        );
      } catch (e) {
        thrown = true;
      }
      expect(thrown).to.be(true);

      thrown = false;
      try {
        expressionToGlsl(
          context,
          ['case', true, 'red', false, 'yellow', 'not_a_color'],
          ValueTypes.COLOR
        );
      } catch (e) {
        thrown = true;
      }
      expect(thrown).to.be(true);
    });

    it('throws if invalid argument count', function () {
      let thrown = false;
      try {
        expressionToGlsl(context, ['case', true, 0, false, 1]);
      } catch (e) {
        thrown = true;
      }
      expect(thrown).to.be(true);

      thrown = false;
      try {
        expressionToGlsl(context, ['case', true, 0]);
      } catch (e) {
        thrown = true;
      }
      expect(thrown).to.be(true);

      try {
        expressionToGlsl(context, ['case', false]);
      } catch (e) {
        thrown = true;
      }
      expect(thrown).to.be(true);
    });

    it('correctly parses the expression (colors)', function () {
      expect(
        expressionToGlsl(
          context,
          [
            'case',
            ['>', ['get', 'attr'], 3],
            'red',
            ['>', ['get', 'attr'], 1],
            'yellow',
            'white',
          ],
          ValueTypes.COLOR
        )
      ).to.eql(
        '((a_attr > 3.0) ? vec4(1.0, 0.0, 0.0, 1.0) : ((a_attr > 1.0) ? vec4(1.0, 1.0, 0.0, 1.0) : vec4(1.0, 1.0, 1.0, 1.0)))'
      );
    });
  });

  describe('match operator', function () {
    let context;

    beforeEach(function () {
      context = {
        variables: [],
        attributes: [],
        stringLiteralsMap: {},
        functions: {},
      };
    });

    it('correctly guesses the output type', function () {
      expect(
        getValueType(['match', ['get', 'attr'], 0, 'red', 1, 'yellow', 'green'])
      ).to.eql(ValueTypes.STRING | ValueTypes.COLOR);
      expect(
        getValueType([
          'match',
          ['get', 'attr'],
          0,
          'not_a_color',
          1,
          'yellow',
          'green',
        ])
      ).to.eql(ValueTypes.STRING);
      expect(
        getValueType([
          'match',
          ['get', 'attr'],
          0,
          'red',
          1,
          'yellow',
          'not_a_color',
        ])
      ).to.eql(ValueTypes.STRING);
      expect(
        getValueType([
          'match',
          ['get', 'attr'],
          0,
          [1, 1, 0],
          1,
          [1, 0, 1],
          [0, 1, 1],
        ])
      ).to.eql(ValueTypes.COLOR | ValueTypes.NUMBER_ARRAY);
      expect(
        getValueType([
          'match',
          ['get', 'attr'],
          0,
          [1, 1, 0],
          1,
          [1, 0, 1],
          'white',
        ])
      ).to.eql(ValueTypes.COLOR);
      expect(
        getValueType(['match', ['get', 'attr'], 0, 'red', 1, true, 100])
      ).to.eql(ValueTypes.NONE);
      expect(
        getValueType(['match', ['get', 'attr'], 0, false, 1, true, false])
      ).to.eql(ValueTypes.BOOLEAN);
      expect(
        getValueType(['match', ['get', 'attr'], 0, 100, 1, 200, 300])
      ).to.eql(ValueTypes.NUMBER);
    });

    it('throws if no single output type could be inferred', function () {
      let thrown = false;
      try {
        expressionToGlsl(
          context,
          ['match', ['get', 'attr'], 0, 'red', 1, 'yellow', 'green'],
          ValueTypes.COLOR
        );
      } catch (e) {
        thrown = true;
      }
      expect(thrown).to.be(false);

      try {
        expressionToGlsl(context, [
          'match',
          ['get', 'attr'],
          0,
          'red',
          1,
          'yellow',
          'green',
        ]);
      } catch (e) {
        thrown = true;
      }
      expect(thrown).to.be(true);

      thrown = false;
      try {
        expressionToGlsl(
          context,
          ['match', ['get', 'attr'], 0, 'red', 1, 'yellow', 'green'],
          ValueTypes.NUMBER
        );
      } catch (e) {
        thrown = true;
      }
      expect(thrown).to.be(true);
    });

    it('throws if invalid argument count', function () {
      let thrown = false;
      try {
        expressionToGlsl(context, [
          'match',
          ['get', 'attr'],
          0,
          true,
          false,
          false,
        ]);
      } catch (e) {
        thrown = true;
      }
      expect(thrown).to.be(true);

      thrown = false;
      try {
        expressionToGlsl(context, ['match', ['get', 'attr'], 0, true]);
      } catch (e) {
        thrown = true;
      }
      expect(thrown).to.be(true);

      try {
        expressionToGlsl(context, ['match', ['get', 'attr'], 0]);
      } catch (e) {
        thrown = true;
      }
      expect(thrown).to.be(true);
    });

    it('correctly parses the expression (colors)', function () {
      expect(
        expressionToGlsl(
          context,
          ['match', ['get', 'attr'], 0, 'red', 1, 'yellow', 'white'],
          ValueTypes.COLOR
        )
      ).to.eql(
        '(a_attr == 0.0 ? vec4(1.0, 0.0, 0.0, 1.0) : (a_attr == 1.0 ? vec4(1.0, 1.0, 0.0, 1.0) : vec4(1.0, 1.0, 1.0, 1.0)))'
      );
    });

    it('correctly parses the expression (strings)', function () {
      function toGlsl(string) {
        return stringToGlsl(context, string);
      }
      expect(
        expressionToGlsl(
          context,
          ['match', ['get', 'attr'], 10, 'red', 20, 'yellow', 'white'],
          ValueTypes.STRING
        )
      ).to.eql(
        `(a_attr == 10.0 ? ${toGlsl('red')} : (a_attr == 20.0 ? ${toGlsl(
          'yellow'
        )} : ${toGlsl('white')}))`
      );
    });

    it('correctly parses the expression (number arrays)', function () {
      function toGlsl(string) {
        return stringToGlsl(context, string);
      }
      expect(
        expressionToGlsl(context, [
          'match',
          ['get', 'attr'],
          'low',
          [0, 0],
          'high',
          [0, 1],
          [1, 0],
        ])
      ).to.eql(
        `(a_attr == ${toGlsl('low')} ? vec2(0.0, 0.0) : (a_attr == ${toGlsl(
          'high'
        )} ? vec2(0.0, 1.0) : vec2(1.0, 0.0)))`
      );
      expect(
        expressionToGlsl(
          context,
          [
            'match',
            ['get', 'attr'],
            0,
            [0, 0, 1, 1],
            1,
            [1, 1, 2, 2],
            2,
            [2, 2, 3, 3],
            [3, 3, 4, 4],
          ],
          ValueTypes.NUMBER_ARRAY
        )
      ).to.eql(
        '(a_attr == 0.0 ? vec4(0.0, 0.0, 1.0, 1.0) : (a_attr == 1.0 ? vec4(1.0, 1.0, 2.0, 2.0) : (a_attr == 2.0 ? vec4(2.0, 2.0, 3.0, 3.0) : vec4(3.0, 3.0, 4.0, 4.0))))'
      );
    });
  });

  describe('interpolate operator', function () {
    let context;

    beforeEach(function () {
      context = {
        variables: [],
        attributes: [],
        stringLiteralsMap: {},
        functions: {},
      };
    });

    it('correctly guesses the output type', function () {
      expect(
        getValueType([
          'interpolate',
          ['linear'],
          ['get', 'attr'],
          0,
          'red',
          100,
          'yellow',
        ])
      ).to.eql(ValueTypes.COLOR);
      expect(
        getValueType([
          'interpolate',
          ['linear'],
          ['get', 'attr'],
          0,
          [1, 2, 3],
          1,
          [0, 0, 0, 4],
        ])
      ).to.eql(ValueTypes.COLOR);
      expect(
        getValueType([
          'interpolate',
          ['linear'],
          ['get', 'attr'],
          1000,
          -10,
          2000,
          10,
        ])
      ).to.eql(ValueTypes.NUMBER);
    });

    it('throws if no single output type could be inferred', function () {
      let thrown = false;
      try {
        expressionToGlsl(
          context,
          ['interpolate', ['linear'], ['get', 'attr'], 1000, -10, 2000, 10],
          ValueTypes.COLOR
        );
      } catch (e) {
        thrown = true;
      }
      expect(thrown).to.be(true);

      try {
        expressionToGlsl(context, [
          'interpolate',
          ['linear'],
          ['get', 'attr'],
          0,
          [1, 2, 3],
          1,
          222,
        ]);
      } catch (e) {
        thrown = true;
      }
      expect(thrown).to.be(true);

      thrown = false;
      try {
        expressionToGlsl(
          context,
          [
            'interpolate',
            ['linear'],
            ['get', 'attr'],
            0,
            [1, 2, 3],
            1,
            [0, 0, 0, 4],
          ],
          ValueTypes.NUMBER
        );
      } catch (e) {
        thrown = true;
      }
      expect(thrown).to.be(true);
    });

    it('throws if invalid argument count', function () {
      let thrown = false;
      try {
        expressionToGlsl(context, [
          'interpolate',
          ['linear'],
          ['get', 'attr'],
          1000,
        ]);
      } catch (e) {
        thrown = true;
      }
      expect(thrown).to.be(true);

      thrown = false;
      try {
        expressionToGlsl(context, [
          'interpolate',
          ['linear'],
          ['get', 'attr'],
          1000,
          -10,
          2000,
          10,
          5000,
        ]);
      } catch (e) {
        thrown = true;
      }
      expect(thrown).to.be(true);
    });

    it('throws if an invalid interpolation type is given', function () {
      let thrown = false;
      try {
        expressionToGlsl(context, [
          'interpolate',
          'linear',
          ['get', 'attr'],
          1000,
          0,
          2000,
          1,
        ]);
      } catch (e) {
        thrown = true;
      }
      expect(thrown).to.be(true);

      thrown = false;
      try {
        expressionToGlsl(context, [
          'interpolate',
          ['exponential'],
          ['get', 'attr'],
          1000,
          -10,
          2000,
          1,
        ]);
      } catch (e) {
        thrown = true;
      }
      expect(thrown).to.be(true);

      thrown = false;
      try {
        expressionToGlsl(context, [
          'interpolate',
          ['not_a_type'],
          ['get', 'attr'],
          1000,
          -10,
          2000,
          1,
        ]);
      } catch (e) {
        thrown = true;
      }
      expect(thrown).to.be(true);
    });

    it('correctly parses the expression (colors, linear)', function () {
      expect(
        expressionToGlsl(context, [
          'interpolate',
          ['linear'],
          ['get', 'attr'],
          1000,
          [255, 0, 0],
          2000,
          [0, 255, 0],
        ])
      ).to.eql(
        'mix(vec4(1.0, 0.0, 0.0, 1.0), vec4(0.0, 1.0, 0.0, 1.0), pow(clamp((a_attr - 1000.0) / (2000.0 - 1000.0), 0.0, 1.0), 1.0))'
      );
      expect(
        expressionToGlsl(context, [
          'interpolate',
          ['linear'],
          ['get', 'attr'],
          1000,
          [255, 0, 0],
          2000,
          [0, 255, 0],
          5000,
          [0, 0, 255],
        ])
      ).to.eql(
        'mix(mix(vec4(1.0, 0.0, 0.0, 1.0), vec4(0.0, 1.0, 0.0, 1.0), pow(clamp((a_attr - 1000.0) / (2000.0 - 1000.0), 0.0, 1.0), 1.0)), vec4(0.0, 0.0, 1.0, 1.0), pow(clamp((a_attr - 2000.0) / (5000.0 - 2000.0), 0.0, 1.0), 1.0))'
      );
    });

    it('correctly parses the expression (number, linear)', function () {
      expect(
        expressionToGlsl(context, [
          'interpolate',
          ['linear'],
          ['get', 'attr'],
          1000,
          -10,
          2000,
          0,
          5000,
          10,
        ])
      ).to.eql(
        'mix(mix(-10.0, 0.0, pow(clamp((a_attr - 1000.0) / (2000.0 - 1000.0), 0.0, 1.0), 1.0)), 10.0, pow(clamp((a_attr - 2000.0) / (5000.0 - 2000.0), 0.0, 1.0), 1.0))'
      );
    });

    it('correctly parses the expression (number, exponential)', function () {
      expect(
        expressionToGlsl(context, [
          'interpolate',
          ['exponential', 0.5],
          ['get', 'attr'],
          1000,
          -10,
          2000,
          0,
          5000,
          10,
        ])
      ).to.eql(
        'mix(mix(-10.0, 0.0, pow(clamp((a_attr - 1000.0) / (2000.0 - 1000.0), 0.0, 1.0), 0.5)), 10.0, pow(clamp((a_attr - 2000.0) / (5000.0 - 2000.0), 0.0, 1.0), 0.5))'
      );
    });
  });

  describe('complex expressions', function () {
    let context;

    beforeEach(function () {
      context = {
        variables: [],
        attributes: [],
        stringLiteralsMap: {},
        functions: {},
      };
    });

    it('correctly parses a combination of interpolate, match, color and number', function () {
      const expression = [
        'interpolate',
        ['linear'],
        [
          '^',
          [
            '/',
            [
              '%',
              [
                '+',
                ['time'],
                ['interpolate', ['linear'], ['get', 'year'], 1850, 0, 2015, 8],
              ],
              8,
            ],
            8,
          ],
          0.5,
        ],
        0,
        'rgba(255, 255, 0, 0.5)',
        1,
        ['match', ['get', 'year'], 2000, 'green', '#ffe52c'],
      ];
      expect(expressionToGlsl(context, expression)).to.eql(
        'mix(vec4(1.0, 1.0, 0.0, 0.5), (a_year == 2000.0 ? vec4(0.0, 0.5019607843137255, 0.0, 1.0) : vec4(1.0, 0.8980392156862745, 0.17254901960784313, 1.0)), pow(clamp((pow((mod((u_time + mix(0.0, 8.0, pow(clamp((a_year - 1850.0) / (2015.0 - 1850.0), 0.0, 1.0), 1.0))), 8.0) / 8.0), 0.5) - 0.0) / (1.0 - 0.0), 0.0, 1.0), 1.0))'
      );
    });
  });
});
