package twin

import (
	"io"
	"os"
	"runtime/debug"
	"strings"
	"testing"
	"time"

	"gotest.tools/v3/assert"
)

func assertEncode(t *testing.T, incomingString string, expectedEvent Event, expectedRemainder string) {
	actualEvent, actualRemainder := consumeEncodedEvent(incomingString)

	message := strings.Replace(incomingString, "\x1b", "ESC", -1)
	message = strings.Replace(message, "\r", "RET", -1)

	assert.Assert(t, actualEvent != nil,
		"Input: %s Result: %#v Expected: %#v", message, "nil", expectedEvent)
	assert.Equal(t, *actualEvent, expectedEvent,
		"Input: %s Result: %#v Expected: %#v", message, *actualEvent, expectedEvent)
	assert.Equal(t, actualRemainder, expectedRemainder, message)
}

func TestConsumeEncodedEvent(t *testing.T) {
	assertEncode(t, "a", EventRune{rune: 'a'}, "")
	assertEncode(t, "\r", EventKeyCode{keyCode: KeyEnter}, "")
	assertEncode(t, "\x1b", EventKeyCode{keyCode: KeyEscape}, "")

	// Implicitly test having a remaining rune at the end
	assertEncode(t, "\x1b[Ax", EventKeyCode{keyCode: KeyUp}, "x")

	assertEncode(t, "\x1b[<64;127;41M", EventMouse{buttons: MouseWheelUp}, "")
	assertEncode(t, "\x1b[<65;127;41M", EventMouse{buttons: MouseWheelDown}, "")

	// This happens when users paste.
	//
	// Ref: https://github.com/walles/moar/issues/73
	assertEncode(t, "1234", EventRune{rune: '1'}, "234")
}

func TestConsumeEncodedEventWithUnsupportedEscapeCode(t *testing.T) {
	event, remainder := consumeEncodedEvent("\x1bXXXXX")
	assert.Assert(t, event == nil)
	assert.Equal(t, remainder, "")
}

func TestConsumeEncodedEventWithNoInput(t *testing.T) {
	event, remainder := consumeEncodedEvent("")
	assert.Assert(t, event == nil)
	assert.Equal(t, remainder, "")
}

func TestRenderLine(t *testing.T) {
	row := []StyledRune{
		{
			Rune:  '<',
			Style: StyleDefault.WithAttr(AttrReverse),
		},
		{
			Rune:  'f',
			Style: StyleDefault.WithAttr(AttrDim),
		},
	}

	rendered, count := renderLine(row, 33, ColorCount16)
	assert.Equal(t, count, 2)
	reset := "[m"
	reversed := "[7m"
	notReversed := "[27m"
	dim := "[2m"
	clearToEol := "[K"
	assert.Equal(t,
		strings.ReplaceAll(rendered, "", "ESC"),
		strings.ReplaceAll(reset+reversed+"<"+dim+notReversed+"f"+reset+clearToEol, "", "ESC"))
}

func TestRenderLineEmpty(t *testing.T) {
	row := []StyledRune{}

	rendered, count := renderLine(row, 33, ColorCount16)
	assert.Equal(t, count, 0)

	// All lines are expected to stand on their own, so we always need to clear
	// to EOL whether or not the line is empty.
	assert.Equal(t, rendered, "\x1b[m\x1b[K")
}

func TestRenderLineLastReversed(t *testing.T) {
	row := []StyledRune{
		{
			Rune:  '<',
			Style: StyleDefault.WithAttr(AttrReverse),
		},
	}

	rendered, count := renderLine(row, 33, ColorCount16)
	assert.Equal(t, count, 1)
	reset := "[m"
	reversed := "[7m"
	clearToEol := "[K"
	assert.Equal(t,
		strings.ReplaceAll(rendered, "", "ESC"),
		strings.ReplaceAll(reset+reversed+"<"+reset+clearToEol, "", "ESC"))
}

func TestRenderLineLastNonSpace(t *testing.T) {
	row := []StyledRune{
		{
			Rune:  'X',
			Style: StyleDefault,
		},
	}

	rendered, count := renderLine(row, 33, ColorCount16)
	assert.Equal(t, count, 1)
	reset := "[m"
	clearToEol := "[K"
	assert.Equal(t,
		strings.ReplaceAll(rendered, "", "ESC"),
		strings.ReplaceAll(reset+"X"+clearToEol, "", "ESC"))
}

func TestRenderLineLastReversedPlusTrailingSpace(t *testing.T) {
	row := []StyledRune{
		{
			Rune:  '<',
			Style: StyleDefault.WithAttr(AttrReverse),
		},
		{
			Rune:  ' ',
			Style: StyleDefault,
		},
	}

	rendered, count := renderLine(row, 33, ColorCount16)
	assert.Equal(t, count, 1)
	reset := "[m"
	reversed := "[7m"
	clearToEol := "[K"
	assert.Equal(t,
		strings.ReplaceAll(rendered, "", "ESC"),
		strings.ReplaceAll(reset+reversed+"<"+reset+clearToEol, "", "ESC"))
}

func TestRenderLineOnlyTrailingSpaces(t *testing.T) {
	row := []StyledRune{
		{
			Rune:  ' ',
			Style: StyleDefault,
		},
		{
			Rune:  ' ',
			Style: StyleDefault,
		},
	}

	rendered, count := renderLine(row, 33, ColorCount16)
	assert.Equal(t, count, 0)

	// All lines are expected to stand on their own, so we always need to clear
	// to EOL whether or not the line is empty.
	assert.Equal(t, rendered, "\x1b[m\x1b[K")
}

func TestRenderLineLastReversedSpaces(t *testing.T) {
	row := []StyledRune{
		{
			Rune:  ' ',
			Style: StyleDefault.WithAttr(AttrReverse),
		},
	}

	rendered, count := renderLine(row, 33, ColorCount16)
	assert.Equal(t, count, 1)
	reset := "[m"
	reversed := "[7m"
	clearToEol := "[K"
	assert.Equal(t,
		strings.ReplaceAll(rendered, "", "ESC"),
		strings.ReplaceAll(reset+reversed+" "+reset+clearToEol, "", "ESC"))
}

func TestRenderLineNonPrintable(t *testing.T) {
	row := []StyledRune{
		{
			Rune: '',
		},
	}

	rendered, count := renderLine(row, 33, ColorCount16)
	assert.Equal(t, count, 1)
	reset := "[m"
	white := "[37m"
	redBg := "[41m"
	bold := "[1m"
	clearToEol := "[K"
	assert.Equal(t,
		strings.ReplaceAll(rendered, "", "ESC"),
		strings.ReplaceAll(reset+white+redBg+bold+"?"+reset+clearToEol, "", "ESC"))
}

func TestRenderHyperlinkAtEndOfLine(t *testing.T) {
	url := "https://example.com/"
	row := []StyledRune{
		{
			Rune:  '*',
			Style: StyleDefault.WithHyperlink(&url),
		},
	}

	rendered, count := renderLine(row, 33, ColorCount16)
	assert.Equal(t, count, 1)

	assert.Equal(t,
		strings.ReplaceAll(rendered, "", "ESC"),
		`ESC[mESC]8;;`+url+`ESC\*ESC]8;;ESC\ESC[K`)
}

func TestMultiCharHyperlink(t *testing.T) {
	url := "https://example.com/"
	row := []StyledRune{
		{
			Rune:  '-',
			Style: StyleDefault.WithHyperlink(&url),
		},
		{
			Rune:  'X',
			Style: StyleDefault.WithHyperlink(&url),
		},
		{
			Rune:  '-',
			Style: StyleDefault.WithHyperlink(&url),
		},
	}

	rendered, count := renderLine(row, 33, ColorCount16)
	assert.Equal(t, count, 3)

	assert.Equal(t,
		strings.ReplaceAll(rendered, "", "ESC"),
		`ESC[mESC]8;;`+url+`ESC\-X-ESC]8;;ESC\ESC[K`)
}

func TestRenderLineFullWidth(t *testing.T) {
	row := []StyledRune{
		{
			Rune: 'x',
		},
		{
			Rune: 'y',
		},
	}

	rendered, count := renderLine(row, 2, ColorCount16)
	assert.Equal(t, count, 2)

	assert.Equal(t,
		strings.ReplaceAll(rendered, "", "ESC"),
		"ESC[mxy", "Expected no clear-to-EOL at the end of a full-width line")

	rendered, count = renderLine(row, 3, ColorCount16)
	assert.Equal(t, count, 2)

	assert.Equal(t,
		strings.ReplaceAll(rendered, "", "ESC"),
		"ESC[mxyESC[K", "Expected clear-to-EOL at the end of a full-width line")
}

// Test the most basic form of interruptability. Interrupting and sending a byte
// should make the reader return EOF.
//
// What we really want is for the reader to return EOF immediately when
// interrupted, with no write needed.
//
// This test should be replaced by
// TestInterruptableReader_blockedOnReadImmediate if or when the Windows
// implementation catches up.
func TestInterruptableReader_blockedOnRead(t *testing.T) {
	// Make a pipe to read from and write to
	pipeReader, pipeWriter, err := os.Pipe()
	assert.NilError(t, err)

	// Make an interruptable reader
	testMe, err := newInterruptableReader(pipeReader)
	assert.NilError(t, err)
	assert.Assert(t, testMe != nil)

	// Start a thread that reads from the pipe
	type readResult struct {
		n   int
		err error
	}
	readResultChan := make(chan readResult)
	go func() {
		defer func() {
			panicHandler("TestInterruptableReader_blockedOnRead()", recover(), debug.Stack())
		}()

		buffer := make([]byte, 1)
		n, err := testMe.Read(buffer)
		readResultChan <- readResult{n, err}
	}()

	// Give the reader thread some time to start waiting
	time.Sleep(100 * time.Millisecond)

	// Ensure the reader is not done, it should be blocked on the read()
	select {
	case <-readResultChan:
		t.Fatal("Reader should not be done yet")
	default:
	}

	// Interrupt the reader
	testMe.Interrupt()

	// Write a byte to the pipe
	n, err := pipeWriter.Write([]byte{42})
	assert.NilError(t, err)
	assert.Equal(t, n, 1)

	// Wait for the reader thread to finish
	result := <-readResultChan

	// Check the result
	assert.Equal(t, result.n, 0)
	assert.Equal(t, result.err, io.EOF)

	// Another read should return EOF immediately
	buffer := make([]byte, 1)
	n, err = testMe.Read(buffer)
	assert.Equal(t, err, io.EOF)
	assert.Equal(t, n, 0)
}

func TestInterruptableReader_interruptFirstReadLater(t *testing.T) {
	// Make a pipe to read from and write to
	pipeReader, pipeWriter, err := os.Pipe()
	assert.NilError(t, err)

	// Make an interruptable reader
	testMe, err := newInterruptableReader(pipeReader)
	assert.NilError(t, err)
	assert.Assert(t, testMe != nil)

	// Interrupt the reader
	testMe.Interrupt()

	// Write something so that we have something to read
	n, err := pipeWriter.Write([]byte{42})
	assert.NilError(t, err)
	assert.Equal(t, n, 1)

	// Try reading from the interrupted reader
	buffer := make([]byte, 1)
	n, err = testMe.Read(buffer)
	assert.Equal(t, n, 0)
	assert.Equal(t, err, io.EOF)
}

func TestInterruptableReader_justRead(t *testing.T) {
	// Make a pipe to read from and write to
	pipeReader, pipeWriter, err := os.Pipe()
	assert.NilError(t, err)

	// Make an interruptable reader
	testMe, err := newInterruptableReader(pipeReader)
	assert.NilError(t, err)
	assert.Assert(t, testMe != nil)

	// Write something so that we have something to read
	n, err := pipeWriter.Write([]byte{42})
	assert.NilError(t, err)
	assert.Equal(t, n, 1)

	// Try reading from the reader
	buffer := make([]byte, 7)
	n, err = testMe.Read(buffer)
	assert.Equal(t, n, 1)
	assert.NilError(t, err)
	assert.Equal(t, buffer[0], byte(42))
	assert.Equal(t, len(buffer), 7)
}
