package rendertest

import (
	"image"
	"math"
	"testing"

	"gioui.org/f32"
	"gioui.org/op"
	"gioui.org/op/clip"
	"gioui.org/op/paint"
	"golang.org/x/image/colornames"
)

func TestPaintRect(t *testing.T) {
	run(t, func(o *op.Ops) {
		paint.FillShape(o, red, clip.Rect(image.Rect(0, 0, 50, 50)).Op())
	}, func(r result) {
		r.expect(0, 0, colornames.Red)
		r.expect(49, 0, colornames.Red)
		r.expect(50, 0, colornames.White)
		r.expect(10, 50, colornames.White)
	})
}

func TestPaintClippedRect(t *testing.T) {
	run(t, func(o *op.Ops) {
		clip.RRect{Rect: f32.Rect(25, 25, 60, 60)}.Add(o)
		paint.FillShape(o, red, clip.Rect(image.Rect(0, 0, 50, 50)).Op())
	}, func(r result) {
		r.expect(0, 0, colornames.White)
		r.expect(24, 35, colornames.White)
		r.expect(25, 35, colornames.Red)
		r.expect(50, 0, colornames.White)
		r.expect(10, 50, colornames.White)
	})
}

func TestPaintClippedCirle(t *testing.T) {
	run(t, func(o *op.Ops) {
		r := float32(10)
		clip.RRect{Rect: f32.Rect(20, 20, 40, 40), SE: r, SW: r, NW: r, NE: r}.Add(o)
		clip.Rect(image.Rect(0, 0, 30, 50)).Add(o)
		paint.Fill(o, red)
	}, func(r result) {
		r.expect(21, 21, colornames.White)
		r.expect(25, 30, colornames.Red)
		r.expect(31, 30, colornames.White)
	})
}

func TestPaintArc(t *testing.T) {
	run(t, func(o *op.Ops) {
		p := new(clip.Path)
		p.Begin(o)
		p.Move(f32.Pt(0, 20))
		p.Line(f32.Pt(10, 0))
		p.Arc(f32.Pt(10, 0), f32.Pt(40, 0), math.Pi)
		p.Line(f32.Pt(30, 0))
		p.Line(f32.Pt(0, 25))
		p.Arc(f32.Pt(-10, 5), f32.Pt(10, 15), -math.Pi)
		p.Line(f32.Pt(0, 25))
		p.Arc(f32.Pt(10, 10), f32.Pt(10, 10), 2*math.Pi)
		p.Line(f32.Pt(-10, 0))
		p.Arc(f32.Pt(-10, 0), f32.Pt(-40, 0), -math.Pi)
		p.Line(f32.Pt(-10, 0))
		p.Line(f32.Pt(0, -10))
		p.Arc(f32.Pt(-10, -20), f32.Pt(10, -5), math.Pi)
		p.Line(f32.Pt(0, -10))
		p.Line(f32.Pt(-50, 0))
		p.Outline().Add(o)

		paint.FillShape(o, red, clip.Rect(image.Rect(0, 0, 128, 128)).Op())
	}, func(r result) {
		r.expect(0, 0, colornames.White)
		r.expect(0, 25, colornames.Red)
		r.expect(0, 15, colornames.White)
	})
}

func TestPaintTexture(t *testing.T) {
	run(t, func(o *op.Ops) {
		squares.Add(o)
		scale(80.0/512, 80.0/512).Add(o)
		paint.PaintOp{}.Add(o)
	}, func(r result) {
		r.expect(0, 0, colornames.Blue)
		r.expect(79, 10, colornames.Green)
		r.expect(80, 0, colornames.White)
		r.expect(10, 80, colornames.White)
	})
}

func TestPaintClippedTexture(t *testing.T) {
	run(t, func(o *op.Ops) {
		squares.Add(o)
		clip.RRect{Rect: f32.Rect(0, 0, 40, 40)}.Add(o)
		scale(80.0/512, 80.0/512).Add(o)
		paint.PaintOp{}.Add(o)
	}, func(r result) {
		r.expect(40, 40, colornames.White)
		r.expect(25, 35, colornames.Blue)
	})
}

func TestStrokedPathBevelFlat(t *testing.T) {
	run(t, func(o *op.Ops) {
		const width = 2.5
		sty := clip.StrokeStyle{
			Cap:  clip.FlatCap,
			Join: clip.BevelJoin,
		}

		p := new(clip.Path)
		p.Begin(o)
		p.Move(f32.Pt(10, 50))
		p.Line(f32.Pt(10, 0))
		p.Arc(f32.Pt(10, 0), f32.Pt(20, 0), math.Pi)
		p.Line(f32.Pt(10, 0))
		p.Line(f32.Pt(10, 10))
		p.Arc(f32.Pt(0, 30), f32.Pt(0, 30), 2*math.Pi)
		p.Line(f32.Pt(-20, 0))
		p.Quad(f32.Pt(-10, -10), f32.Pt(-30, 30))
		p.Stroke(width, sty).Add(o)

		paint.Fill(o, red)
	}, func(r result) {
		r.expect(0, 0, colornames.White)
		r.expect(10, 50, colornames.Red)
	})
}

func TestStrokedPathBevelRound(t *testing.T) {
	run(t, func(o *op.Ops) {
		const width = 2.5
		sty := clip.StrokeStyle{
			Cap:  clip.RoundCap,
			Join: clip.BevelJoin,
		}

		p := new(clip.Path)
		p.Begin(o)
		p.Move(f32.Pt(10, 50))
		p.Line(f32.Pt(10, 0))
		p.Arc(f32.Pt(10, 0), f32.Pt(20, 0), math.Pi)
		p.Line(f32.Pt(10, 0))
		p.Line(f32.Pt(10, 10))
		p.Arc(f32.Pt(0, 30), f32.Pt(0, 30), 2*math.Pi)
		p.Line(f32.Pt(-20, 0))
		p.Quad(f32.Pt(-10, -10), f32.Pt(-30, 30))
		p.Stroke(width, sty).Add(o)

		paint.Fill(o, red)
	}, func(r result) {
		r.expect(0, 0, colornames.White)
		r.expect(10, 50, colornames.Red)
	})
}

func TestStrokedPathBevelSquare(t *testing.T) {
	run(t, func(o *op.Ops) {
		const width = 2.5
		sty := clip.StrokeStyle{
			Cap:  clip.SquareCap,
			Join: clip.BevelJoin,
		}

		p := new(clip.Path)
		p.Begin(o)
		p.Move(f32.Pt(10, 50))
		p.Line(f32.Pt(10, 0))
		p.Arc(f32.Pt(10, 0), f32.Pt(20, 0), math.Pi)
		p.Line(f32.Pt(10, 0))
		p.Line(f32.Pt(10, 10))
		p.Arc(f32.Pt(0, 30), f32.Pt(0, 30), 2*math.Pi)
		p.Line(f32.Pt(-20, 0))
		p.Quad(f32.Pt(-10, -10), f32.Pt(-30, 30))
		p.Stroke(width, sty).Add(o)

		paint.Fill(o, red)
	}, func(r result) {
		r.expect(0, 0, colornames.White)
		r.expect(10, 50, colornames.Red)
	})
}

func TestStrokedPathRoundRound(t *testing.T) {
	run(t, func(o *op.Ops) {
		const width = 2.5
		sty := clip.StrokeStyle{
			Cap:  clip.RoundCap,
			Join: clip.RoundJoin,
		}

		p := new(clip.Path)
		p.Begin(o)
		p.Move(f32.Pt(10, 50))
		p.Line(f32.Pt(10, 0))
		p.Arc(f32.Pt(10, 0), f32.Pt(20, 0), math.Pi)
		p.Line(f32.Pt(10, 0))
		p.Line(f32.Pt(10, 10))
		p.Arc(f32.Pt(0, 30), f32.Pt(0, 30), 2*math.Pi)
		p.Line(f32.Pt(-20, 0))
		p.Quad(f32.Pt(-10, -10), f32.Pt(-30, 30))
		p.Stroke(width, sty).Add(o)

		paint.Fill(o, red)
	}, func(r result) {
		r.expect(0, 0, colornames.White)
		r.expect(10, 50, colornames.Red)
	})
}

func TestStrokedPathFlatMiter(t *testing.T) {
	run(t, func(o *op.Ops) {
		const width = 10
		sty := clip.StrokeStyle{
			Cap:   clip.FlatCap,
			Join:  clip.BevelJoin,
			Miter: 5,
		}

		beg := f32.Pt(40, 10)
		{
			p := new(clip.Path)
			p.Begin(o)
			p.Move(beg)
			p.Line(f32.Pt(50, 0))
			p.Line(f32.Pt(-50, 50))
			p.Line(f32.Pt(50, 0))
			p.Quad(f32.Pt(-50, 20), f32.Pt(-50, 50))
			p.Line(f32.Pt(50, 0))

			p.Stroke(width, sty).Add(o)
			paint.Fill(o, red)
		}

		{
			p := new(clip.Path)
			p.Begin(o)
			p.Move(beg)
			p.Line(f32.Pt(50, 0))
			p.Line(f32.Pt(-50, 50))
			p.Line(f32.Pt(50, 0))
			p.Quad(f32.Pt(-50, 20), f32.Pt(-50, 50))
			p.Line(f32.Pt(50, 0))

			p.Stroke(2, clip.StrokeStyle{}).Add(o)
			paint.Fill(o, black)
		}

	}, func(r result) {
		r.expect(0, 0, colornames.White)
		r.expect(40, 10, colornames.Black)
		r.expect(40, 12, colornames.Red)
	})
}

func TestStrokedPathFlatMiterInf(t *testing.T) {
	run(t, func(o *op.Ops) {
		const width = 10
		sty := clip.StrokeStyle{
			Cap:   clip.FlatCap,
			Join:  clip.BevelJoin,
			Miter: float32(math.Inf(+1)),
		}

		beg := f32.Pt(40, 10)
		{
			p := new(clip.Path)
			p.Begin(o)
			p.Move(beg)
			p.Line(f32.Pt(50, 0))
			p.Line(f32.Pt(-50, 50))
			p.Line(f32.Pt(50, 0))
			p.Quad(f32.Pt(-50, 20), f32.Pt(-50, 50))
			p.Line(f32.Pt(50, 0))

			p.Stroke(width, sty).Add(o)
			paint.Fill(o, red)
		}

		{
			p := new(clip.Path)
			p.Begin(o)
			p.Move(beg)
			p.Line(f32.Pt(50, 0))
			p.Line(f32.Pt(-50, 50))
			p.Line(f32.Pt(50, 0))
			p.Quad(f32.Pt(-50, 20), f32.Pt(-50, 50))
			p.Line(f32.Pt(50, 0))

			p.Stroke(2, clip.StrokeStyle{}).Add(o)
			paint.Fill(o, black)
		}

	}, func(r result) {
		r.expect(0, 0, colornames.White)
		r.expect(40, 10, colornames.Black)
		r.expect(40, 12, colornames.Red)
	})
}

func TestStrokedPathZeroWidth(t *testing.T) {
	run(t, func(o *op.Ops) {
		const width = 2
		var sty clip.StrokeStyle
		{
			p := new(clip.Path)
			p.Begin(o)
			p.Move(f32.Pt(10, 50))
			p.Line(f32.Pt(50, 0))
			p.Stroke(width, sty).Add(o)

			paint.Fill(o, black)
		}

		{
			p := new(clip.Path)
			p.Begin(o)
			p.Move(f32.Pt(10, 50))
			p.Line(f32.Pt(30, 0))
			p.Stroke(0, sty).Add(o) // width=0, disable stroke

			paint.Fill(o, red)
		}

	}, func(r result) {
		r.expect(0, 0, colornames.White)
		r.expect(10, 50, colornames.Black)
		r.expect(30, 50, colornames.Black)
		r.expect(65, 50, colornames.White)
	})
}