package ui

import (
	"strings"
	"testing"

	"github.com/gdamore/tcell/v2"
)

func rowText(screen tcell.SimulationScreen, y, x0, x1 int) string {
	var b strings.Builder
	for x := x0; x < x1; x++ {
		ch, _, _, _ := screen.GetContent(x, y)
		b.WriteRune(ch)
	}
	return b.String()
}

func TestDetailPaneLayout(t *testing.T) {
	a := newTestApp(t)
	screen := tcell.NewSimulationScreen("")
	if err := screen.Init(); err != nil {
		t.Fatal(err)
	}
	defer screen.Fini()
	screen.SetSize(60, 40)

	d := newDetailPane(a)
	d.SetRect(0, 0, 60, 40)
	d.Show(detailText{head: "[::b]The Matrix (1999)[::-]\nStatus: released", plot: "Plot text goes here"}, coverRef{})

	// Without a poster everything is one text.
	d.Draw(screen)
	if got := rowText(screen, 1, 1, 30); !strings.HasPrefix(got, "The Matrix (1999)") {
		t.Errorf("first line = %q", got)
	}
	if got := rowText(screen, 3, 1, 30); !strings.HasPrefix(got, "Plot text goes here") {
		t.Errorf("without a poster the plot follows the head: %q", got)
	}

	// With a poster: head on the left, poster on the right, plot below both.
	d.hasCover = true
	d.cover.setImage(stripes(40, 60))
	d.Draw(screen)
	if got := rowText(screen, 1, 1, 30); !strings.HasPrefix(got, "The Matrix (1999)") {
		t.Errorf("head moved: %q", got)
	}
	coverX := -1
	for x := 59; x > 30; x-- {
		if ch, _, st, _ := screen.GetContent(x, 1); ch != ' ' || st != tcell.StyleDefault {
			coverX = x
			break
		}
	}
	if coverX < 55 {
		t.Errorf("no poster against the right edge (last drawn column %d)", coverX)
	}
	// The plot starts below the poster: 40*2/5 = 24 columns -> 24*3/2/2 = 18 rows.
	plotRow := -1
	for y := 1; y < 39; y++ {
		if strings.HasPrefix(rowText(screen, y, 1, 30), "Plot text goes here") {
			plotRow = y
			break
		}
	}
	if plotRow < 18 {
		t.Errorf("plot at row %d, want below the poster", plotRow)
	}

	// A pane too short for the poster falls back to plain text.
	d.SetRect(0, 0, 60, 14)
	d.Draw(screen)
	if !d.combined {
		t.Error("a short pane must drop the poster")
	}
}