// FIXME(thaJeztah): remove once we are a module; the go:build directive prevents go from downgrading language version to go1.16:
//go:build go1.26

package image

import (
	"context"
	"fmt"
	"slices"
	"strings"

	"github.com/containerd/platforms"
	"github.com/docker/cli/cli/command"
	"github.com/docker/cli/cli/command/formatter"
	"github.com/docker/cli/internal/tui"
	"github.com/docker/go-units"
	imagetypes "github.com/moby/moby/api/types/image"
	"github.com/moby/moby/client"
	"github.com/morikuni/aec"
	"github.com/opencontainers/go-digest"
)

const untaggedName = "<untagged>"

type treeOptions struct {
	images   []imagetypes.Summary
	filters  client.Filters
	expanded bool
}

type treeView struct {
	images []topImage

	// imageSpacing indicates whether there should be extra spacing between images.
	imageSpacing bool
}

func runTree(ctx context.Context, dockerCLI command.Cli, opts treeOptions) (int, error) {
	images := opts.images

	view := treeView{
		images: make([]topImage, 0, len(images)),
	}
	attested := make(map[digest.Digest]bool)

	for _, img := range images {
		if ctx.Err() != nil {
			return 0, ctx.Err()
		}
		topDetails := imageDetails{
			ID:        img.ID,
			DiskUsage: units.HumanSizeWithPrecision(float64(img.Size), 3),
			InUse:     img.Containers > 0,
		}

		var totalContent int64
		children := make([]subImage, 0, len(img.Manifests))
		for _, im := range img.Manifests {
			totalContent += im.Size.Content

			if im.Kind == imagetypes.ManifestKindAttestation {
				attested[im.AttestationData.For] = true
				continue
			}
			if im.Kind != imagetypes.ManifestKindImage {
				continue
			}

			inUse := len(im.ImageData.Containers) > 0
			if inUse {
				// Mark top-level parent image as used if any of its subimages are used.
				topDetails.InUse = true
			}

			if !opts.expanded {
				continue
			}

			sub := subImage{
				Platform:  platforms.Format(im.ImageData.Platform),
				Available: im.Available,
				Details: imageDetails{
					ID:          im.ID,
					DiskUsage:   units.HumanSizeWithPrecision(float64(im.Size.Total), 3),
					InUse:       inUse,
					ContentSize: units.HumanSizeWithPrecision(float64(im.Size.Content), 3),
				},
			}

			children = append(children, sub)

			// Add extra spacing between images if there's at least one entry with children.
			view.imageSpacing = true
		}

		topDetails.ContentSize = units.HumanSizeWithPrecision(float64(totalContent), 3)

		// Sort tags for this image
		sortedTags := make([]string, len(img.RepoTags))
		copy(sortedTags, img.RepoTags)
		slices.Sort(sortedTags)

		if opts.expanded {
			view.images = append(view.images, topImage{
				Names:    sortedTags,
				Details:  topDetails,
				Children: children,
				created:  img.Created,
			})
			continue
		}

		if len(sortedTags) == 0 {
			view.images = append(view.images, topImage{
				Details:  topDetails,
				Children: children,
				created:  img.Created,
			})
		}
		for _, tag := range sortedTags {
			view.images = append(view.images, topImage{
				Names:    []string{tag},
				Details:  topDetails,
				Children: children,
				created:  img.Created,
			})
		}
	}

	slices.SortFunc(view.images, func(a, b topImage) int {
		nameA := ""
		if len(a.Names) > 0 {
			nameA = a.Names[0]
		}
		nameB := ""
		if len(b.Names) > 0 {
			nameB = b.Names[0]
		}
		// Empty names sort last
		if (nameA == "") != (nameB == "") {
			if nameB == "" {
				return -1
			}
			return 1
		}
		return strings.Compare(nameA, nameB)
	})

	printImageTree(dockerCLI, view)
	return len(view.images), nil
}

type imageDetails struct {
	ID          string
	DiskUsage   string
	InUse       bool
	ContentSize string
}

type topImage struct {
	Names    []string
	Details  imageDetails
	Children []subImage

	created int64
}

type subImage struct {
	Platform  string
	Available bool
	Details   imageDetails
}

const columnSpacing = 3

var chipInUse = imageChip{
	letter: "U",
	desc:   "In Use",
	fg:     0,
	bg:     14,
	check:  func(d *imageDetails) bool { return d.InUse },
}

var chipPlaceholder = tui.Str{
	Plain: " ",
	Fancy: "   ",
}

type imageChip struct {
	desc   string
	fg, bg int
	letter string
	check  func(*imageDetails) bool
}

func (c imageChip) String(isTerm bool) string {
	return tui.Str{
		Plain: c.letter,
		Fancy: tui.Chip(c.fg, c.bg, " "+c.letter+" "),
	}.String(isTerm)
}

var allChips = []imageChip{
	chipInUse,
}

// getPossibleChips returns the list of chips used by at least one image.
// It is used to determine which columns to print (and how much width to
// reserve).
func getPossibleChips(view treeView) (chips []imageChip) {
	remaining := slices.Clone(allChips)

	check := func(d imageDetails) (done bool) {
		// filter without allocating
		out := remaining[:0]
		for _, chip := range remaining {
			if chip.check(&d) {
				chips = append(chips, chip)
				continue
			}
			out = append(out, chip)
		}
		remaining = out
		return len(remaining) == 0
	}

	for _, img := range view.images {
		if check(img.Details) {
			return chips
		}
		for _, c := range img.Children {
			if check(c.Details) {
				return chips
			}
		}
	}

	return chips
}

func printImageTree(outs command.Streams, view treeView) {
	out := tui.NewOutput(outs.Out())
	isTerm := out.IsTerminal()

	_, width := out.GetTtySize()
	limitWidth := width == 0
	if isTerm && width < 20 {
		width = 20
	}

	topNameColor := out.Color(aec.NewBuilder(aec.BlueF, aec.Bold).ANSI)
	normalColor := out.Color(tui.ColorSecondary)
	untaggedColor := out.Color(tui.ColorTertiary)
	titleColor := out.Color(tui.ColorTitle)

	// Legend is right-aligned, so don't print it if the width is unlimited
	if !limitWidth {
		out.Println(generateLegend(out, width))
	}

	possibleChips := getPossibleChips(view)
	columns := []imgColumn{
		{
			Title:      "Image",
			Align:      alignLeft,
			Width:      0,
			NoEllipsis: true,
		},
		{
			Title: "ID",
			Align: alignLeft,
			Width: 12,
			DetailsValue: func(d *imageDetails) string {
				return formatter.TruncateID(d.ID)
			},
		},
		{
			Title: "Disk usage",
			Align: alignRight,
			Width: 10,
			DetailsValue: func(d *imageDetails) string {
				return d.DiskUsage
			},
		},
		{
			Title: "Content size",
			Align: alignRight,
			Width: 12,
			DetailsValue: func(d *imageDetails) string {
				return d.ContentSize
			},
		},
		{
			Title: "Extra",
			Align: alignLeft,
			Width: func() int {
				maxChipsWidth := 0
				for _, chip := range possibleChips {
					s := out.Sprint(chip)
					l := tui.Width(s)
					maxChipsWidth += l
				}

				le := len("Extra")
				if le > maxChipsWidth {
					return le
				}
				return maxChipsWidth
			}(),
			Color: &tui.ColorNone,
			DetailsValue: func(d *imageDetails) string {
				var b strings.Builder
				for _, chip := range possibleChips {
					if chip.check(d) {
						b.WriteString(out.Sprint(chip))
					} else {
						b.WriteString(out.Sprint(chipPlaceholder))
					}
				}
				return b.String()
			},
		},
	}

	columns = adjustColumns(width, columns, view.images)

	// Print columns
	for i, h := range columns {
		if i > 0 {
			_, _ = fmt.Fprint(out, strings.Repeat(" ", columnSpacing))
		}

		_, _ = fmt.Fprint(out, h.Print(titleColor, strings.ToUpper(h.Title)))
	}
	_, _ = fmt.Fprintln(out)

	// Print images
	for _, img := range view.images {
		printNames(out, columns, img, topNameColor, untaggedColor)
		printDetails(out, columns, normalColor, img.Details)

		if len(img.Children) > 0 || view.imageSpacing {
			_, _ = fmt.Fprintln(out)
		}
		printChildren(out, columns, img, normalColor)
		_, _ = fmt.Fprintln(out)
	}
}

// adjustColumns adjusts the width of the first column to maximize the space
// available for image names and removes any columns that would be too narrow
// to display their content.
func adjustColumns(width uint, columns []imgColumn, images []topImage) []imgColumn {
	nameWidth := int(width)
	if nameWidth > 0 {
		for idx, h := range columns {
			if h.Width == 0 {
				continue
			}
			d := h.Width
			if idx > 0 {
				d += columnSpacing
			}
			// If the first column gets too short, remove remaining columns
			if nameWidth-d < 12 {
				columns = columns[:idx]
				break
			}
			nameWidth -= d
		}
	}

	// Try to make the first column as narrow as possible
	widest := widestFirstColumnValue(columns, images)
	if width == 0 || nameWidth > widest {
		nameWidth = widest
	}
	columns[0].Width = nameWidth
	return columns
}

func generateLegend(out tui.Output, width uint) string {
	var legend string
	legend += out.Sprint(tui.InfoHeader)
	var legendSb371 strings.Builder
	for idx, chip := range allChips {
		legendSb371.WriteString(" " + out.Sprint(chip) + " " + chip.desc)
		if idx < len(allChips)-1 {
			legendSb371.WriteString(" |")
		}
	}
	legend += legendSb371.String()

	r := max(int(width)-tui.Width(legend), 0)
	legend = strings.Repeat(" ", r) + legend
	return legend
}

func printDetails(out tui.Output, headers []imgColumn, defaultColor aec.ANSI, details imageDetails) {
	for _, h := range headers {
		if h.DetailsValue == nil {
			continue
		}

		_, _ = fmt.Fprint(out, strings.Repeat(" ", columnSpacing))
		clr := defaultColor
		if h.Color != nil {
			clr = *h.Color
		}
		val := h.DetailsValue(&details)
		_, _ = fmt.Fprint(out, h.Print(clr, val))
	}
}

func printChildren(out tui.Output, headers []imgColumn, img topImage, normalColor aec.ANSI) {
	for idx, sub := range img.Children {
		clr := normalColor
		if !sub.Available {
			clr = normalColor.With(aec.Faint)
		}

		text := sub.Platform
		if idx != len(img.Children)-1 {
			_, _ = fmt.Fprint(out, headers[0].Print(clr, "├─ "+text))
		} else {
			_, _ = fmt.Fprint(out, headers[0].Print(clr, "└─ "+text))
		}

		printDetails(out, headers, clr, sub.Details)
		_, _ = fmt.Fprintln(out, "")
	}
}

func printNames(out tui.Output, headers []imgColumn, img topImage, color, untaggedColor aec.ANSI) {
	if len(img.Names) == 0 {
		_, _ = fmt.Fprint(out, headers[0].Print(untaggedColor, untaggedName))
	}

	for nameIdx, name := range img.Names {
		nameWidth := tui.Width(name)
		lastName := nameIdx == len(img.Names)-1
		multiLine := nameWidth > headers[0].Width

		_, _ = fmt.Fprint(out, headers[0].Print(color, name))

		// Print each name on its own line, including the last,
		// unless the last name fits into the column.
		//
		// IMAGE      ID             ...
		// anImage    171e65262c80   ...
		// firstName
		// lastNameIsALongOne
		//            eade5be814e8   ...
		// anotherLongName
		//            bb747ca923a5   ...
		if !lastName || multiLine {
			_, _ = fmt.Fprintln(out)
		}
		if multiLine && lastName {
			_, _ = fmt.Fprint(out, strings.Repeat(" ", headers[0].Width))
		}
	}
}

type alignment int

const (
	alignLeft alignment = iota
	alignCenter
	alignRight
)

type imgColumn struct {
	Title string
	Width int
	Align alignment

	DetailsValue func(*imageDetails) string
	Color        *aec.ANSI
	NoEllipsis   bool
}

func (h imgColumn) Print(clr aec.ANSI, s string) string {
	switch h.Align {
	case alignCenter:
		return h.PrintC(clr, s)
	case alignRight:
		return h.PrintR(clr, s)
	case alignLeft:
	}
	return h.PrintL(clr, s)
}

func (h imgColumn) PrintC(clr aec.ANSI, s string) string {
	ln := tui.Width(s)

	fill := h.Width - ln

	if fill < 0 {
		if h.NoEllipsis {
			fill = 0
		} else {
			return clr.Apply(tui.Ellipsis(s, h.Width))
		}
	}

	l := fill / 2
	r := fill - l

	return strings.Repeat(" ", l) + clr.Apply(s) + strings.Repeat(" ", r)
}

func (h imgColumn) PrintL(clr aec.ANSI, s string) string {
	ln := tui.Width(s)

	fill := h.Width - ln

	if fill < 0 {
		if h.NoEllipsis {
			fill = 0
		} else {
			return clr.Apply(tui.Ellipsis(s, h.Width))
		}
	}

	return clr.Apply(s) + strings.Repeat(" ", fill)
}

func (h imgColumn) PrintR(clr aec.ANSI, s string) string {
	ln := tui.Width(s)
	fill := h.Width - ln

	if fill < 0 {
		if h.NoEllipsis {
			fill = 0
		} else {
			return clr.Apply(tui.Ellipsis(s, h.Width))
		}
	}

	return strings.Repeat(" ", fill) + clr.Apply(s)
}

// widestFirstColumnValue calculates the width needed to fully display the image names and platforms.
func widestFirstColumnValue(headers []imgColumn, images []topImage) int {
	width := len(headers[0].Title)
	for _, img := range images {
		names := img.Names
		if len(names) == 0 {
			names = []string{untaggedName}
		}
		for _, name := range names {
			if len(name) > width {
				width = len(name)
			}
		}
		for _, sub := range img.Children {
			pl := len(sub.Platform) + len("└─ ")
			if pl > width {
				width = pl
			}
		}
	}
	return width
}