package ui

import (
	"fmt"
	"io"

	"charm.land/bubbles/v2/list"
	tea "charm.land/bubbletea/v2"
	"charm.land/lipgloss/v2"

	"git.morlana.online/f.weber/vault-tui/internal/ui/theme"
	"git.morlana.online/f.weber/vault-tui/internal/vault"
)

// entryItem implements list.Item for every row shown in the mounts and
// browser screens: a secret mount, a "directory" (a KV path prefix), or a
// leaf secret.
type entryItem struct {
	label       string // display text, e.g. "secret/" or "team/prod/"
	desc        string
	mount       vault.Mount // set for mount rows and (copied through) for dir/leaf rows
	relPath     string      // path relative to mount, "" at mount root
	isMount     bool
	isDir       bool
	unsupported bool
}

func (e entryItem) FilterValue() string { return e.label }

func mountItems(mounts []vault.Mount) []entryItem {
	items := make([]entryItem, 0, len(mounts))
	for _, mnt := range mounts {
		desc := mnt.Type
		if mnt.Description != "" {
			desc = fmt.Sprintf("%s — %s", mnt.Type, mnt.Description)
		}
		items = append(items, entryItem{
			label: mnt.Path, desc: desc, mount: mnt, isMount: true, unsupported: !mnt.Supported(),
		})
	}
	return items
}

func listingItems(mount vault.Mount, listing vault.Listing) []entryItem {
	items := make([]entryItem, 0, len(listing.Dirs)+len(listing.Leaves))
	for _, d := range listing.Dirs {
		items = append(items, entryItem{label: d, desc: "directory", mount: mount, relPath: listing.Path + d, isDir: true})
	}
	for _, l := range listing.Leaves {
		items = append(items, entryItem{label: l, desc: "secret", mount: mount, relPath: listing.Path + l})
	}
	return items
}

// entryDelegate is a from-scratch list.ItemDelegate: a cursor bar, a type
// symbol, the label (with filter matches highlighted), and a right-aligned
// badge — replacing bubbles/list's DefaultDelegate, which has no notion of
// our entry types or theme.
type entryDelegate struct {
	styles *theme.Styles
}

func (d entryDelegate) Height() int                         { return 1 }
func (d entryDelegate) Spacing() int                        { return 0 }
func (d entryDelegate) Update(tea.Msg, *list.Model) tea.Cmd { return nil }

func (d entryDelegate) Render(w io.Writer, lm list.Model, index int, item list.Item) {
	e, ok := item.(entryItem)
	if !ok {
		return
	}
	width := lm.Width()
	if width <= 0 {
		return
	}
	selected := index == lm.Index() && lm.FilterState() != list.Filtering

	sym, badge := symSecret, "secret"
	switch {
	case e.isMount:
		sym, badge = symMount, engineLabel(e.mount)
	case e.isDir:
		sym, badge = symDir, "dir"
	case e.unsupported:
		sym, badge = symUnsupported, e.mount.Type+" (unsupported)"
	}

	cursor := "  "
	if selected {
		cursor = d.styles.Title.Render(symCursor) + " "
	}
	cursorW := lipgloss.Width(cursor)

	badgeStr := d.styles.Badge.Render(badge)
	if selected {
		badgeStr = d.styles.RowSelected.Render(" " + badge + " ")
	}
	badgeW := lipgloss.Width(badgeStr)

	labelW := width - cursorW - badgeW - 2
	if labelW < 4 {
		labelW = 4
	}

	base := d.rowStyle(e, selected)
	label := truncate(sym+" "+e.label, labelW)
	highlighted := false
	if lm.FilterState() == list.Filtering || lm.FilterState() == list.FilterApplied {
		if matches := lm.MatchesForItem(index); len(matches) > 0 {
			unmatched := base.Inline(true)
			matched := unmatched.Underline(true)
			label = lipgloss.StyleRunes(label, shiftMatches(matches, 2), matched, unmatched)
			highlighted = true
		}
	}
	if !highlighted {
		label = base.Render(label)
	}

	pad := width - cursorW - lipgloss.Width(label) - badgeW
	if pad < 1 {
		pad = 1
	}
	fmt.Fprint(w, cursor+label+lipgloss.NewStyle().Width(pad-1).Render("")+" "+badgeStr)
}

// rowStyle picks the base row style for an entry, accounting for
// selection and the dimmed "unsupported engine" case.
func (d *entryDelegate) rowStyle(e entryItem, selected bool) lipgloss.Style {
	switch {
	case selected:
		return d.styles.RowSelected
	case e.unsupported:
		return d.styles.RowDim
	case e.isDir:
		return d.styles.DirText
	default:
		return d.styles.Row
	}
}

// shiftMatches offsets filter-match rune indices by the width of the
// symbol+space prefix Render prepends to the label before highlighting.
func shiftMatches(matches []int, offset int) []int {
	out := make([]int, len(matches))
	for i, m := range matches {
		out[i] = m + offset
	}
	return out
}