package ui

import (
	"fmt"
	"strings"

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

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

// --- editor: create/update a KV secret -----------------------------------

func (m *Model) newSecret() (tea.Model, tea.Cmd) {
	f := m.currentFrame()
	m.editMount, m.editPath, m.editIsNew, m.editSecret = f.mount, f.path, true, nil
	m.editName = m.newTextInput(fieldSpec{label: "secret name"})
	cmd := m.editName.Focus()
	m.editKeys = []textInput{m.newTextInput(fieldSpec{label: "key"})}
	m.editVals = []textInput{m.newTextInput(fieldSpec{label: "value"})}
	m.editFocus = -1 // -1 == the name field
	m.editSnap = m.editSnapshot()
	m.push(frame{scr: scrEditor, mount: f.mount, path: f.path})
	return m, cmd
}

func (m *Model) editSelected() (tea.Model, tea.Cmd) {
	if m.secret == nil {
		return m, nil
	}
	f := m.currentFrame()
	m.editMount, m.editPath, m.editIsNew, m.editSecret = f.mount, f.path, false, m.secret
	m.editKeys, m.editVals = nil, nil
	for _, k := range sortedKeys(m.secret.Data) {
		m.editKeys = append(m.editKeys, m.textInputWithValue("key", k))
		m.editVals = append(m.editVals, m.textInputWithValue("value", fmt.Sprint(m.secret.Data[k])))
	}
	if len(m.editKeys) == 0 {
		m.editKeys = []textInput{m.newTextInput(fieldSpec{label: "key"})}
		m.editVals = []textInput{m.newTextInput(fieldSpec{label: "value"})}
	}
	m.editFocus = 0
	cmd := m.editKeys[0].Focus()
	m.editSnap = m.editSnapshot()
	m.push(frame{scr: scrEditor, mount: f.mount, path: f.path})
	return m, cmd
}

// editSnapshot serializes the editor's current field values so esc can
// tell whether anything actually changed before asking to discard.
func (m *Model) editSnapshot() string {
	var b strings.Builder
	b.WriteString(m.editName.Value())
	for i := range m.editKeys {
		b.WriteByte(0)
		b.WriteString(m.editKeys[i].Value())
		b.WriteByte('=')
		b.WriteString(m.editVals[i].Value())
	}
	return b.String()
}

func (m *Model) updateEditor(msg tea.Msg) (tea.Model, tea.Cmd) {
	switch msg := msg.(type) {
	case writeAckMsg:
		m.loading = false
		if msg.err != nil {
			return m, func() tea.Msg { return errMsg{err: msg.err} }
		}
		toastCmd := m.notify(toastSuccess, "saved (version %d)", msg.ack.Version)
		savedPath := msg.ack.Path
		m.pop()
		if m.top() == scrSecret {
			return m, tea.Batch(toastCmd, m.loadSecret(m.editMount, savedPath, 0))
		}
		return m, tea.Batch(toastCmd, m.reloadTop())

	case tea.KeyPressMsg:
		switch msg.String() {
		case "esc":
			if m.editSnapshot() != m.editSnap {
				m.confirm = &confirmSpec{
					title:  "Discard changes?",
					body:   "Unsaved edits to this secret will be lost.",
					danger: true,
					onConfirm: func() tea.Cmd {
						m.pop()
						return nil
					},
				}
				return m, nil
			}
			m.pop()
			return m, nil
		case "ctrl+a":
			m.editKeys = append(m.editKeys, m.newTextInput(fieldSpec{label: "key"}))
			m.editVals = append(m.editVals, m.newTextInput(fieldSpec{label: "value"}))
			return m, nil
		case "ctrl+x":
			return m, m.removeCurrentField()
		case "ctrl+s":
			return m.saveEditor()
		case "tab":
			return m, m.moveEditFocus(1)
		case "shift+tab":
			return m, m.moveEditFocus(-1)
		}
		return m.updateEditorInput(msg)
	}
	return m.updateEditorInput(msg)
}

// focus encoding: -1 = name field (new-secret only), 2*i = key[i], 2*i+1 = val[i]
func (m *Model) moveEditFocus(delta int) tea.Cmd {
	maxIdx := len(m.editKeys)*2 - 1
	m.blurEdit()
	if m.editIsNew {
		m.editFocus += delta
		if m.editFocus < -1 {
			m.editFocus = maxIdx
		} else if m.editFocus > maxIdx {
			m.editFocus = -1
		}
	} else {
		if maxIdx < 0 {
			return nil
		}
		m.editFocus = (m.editFocus + delta + maxIdx + 1) % (maxIdx + 1)
	}
	return m.focusEdit()
}

func (m *Model) removeCurrentField() tea.Cmd {
	if m.editFocus < 0 || len(m.editKeys) == 0 {
		return nil
	}
	i := m.editFocus / 2
	if len(m.editKeys) <= 1 {
		m.editKeys[0] = m.newTextInput(fieldSpec{label: "key"})
		m.editVals[0] = m.newTextInput(fieldSpec{label: "value"})
		m.editFocus = 0
		return m.editKeys[0].Focus()
	}
	m.editKeys = append(m.editKeys[:i], m.editKeys[i+1:]...)
	m.editVals = append(m.editVals[:i], m.editVals[i+1:]...)
	if m.editFocus >= len(m.editKeys)*2 {
		m.editFocus = len(m.editKeys)*2 - 1
	}
	return m.focusEdit()
}

func (m *Model) blurEdit() {
	if m.editFocus == -1 {
		m.editName.Blur()
		return
	}
	i, isKey := m.editFocus/2, m.editFocus%2 == 0
	if i >= len(m.editKeys) {
		return
	}
	if isKey {
		m.editKeys[i].Blur()
	} else {
		m.editVals[i].Blur()
	}
}

func (m *Model) focusEdit() tea.Cmd {
	if m.editFocus == -1 {
		return m.editName.Focus()
	}
	i, isKey := m.editFocus/2, m.editFocus%2 == 0
	if i >= len(m.editKeys) {
		return nil
	}
	if isKey {
		return m.editKeys[i].Focus()
	}
	return m.editVals[i].Focus()
}

// updateEditorInput forwards msg to whichever field is focused — every
// message type, not just key presses, so a textinput's own async commands
// (cursor blink, paste) actually reach it instead of being dropped by the
// screen dispatch above.
func (m *Model) updateEditorInput(msg tea.Msg) (tea.Model, tea.Cmd) {
	var cmd tea.Cmd
	if m.editFocus == -1 {
		m.editName, cmd = m.editName.Update(msg)
		return m, cmd
	}
	if len(m.editKeys) == 0 {
		return m, nil
	}
	i, isKey := m.editFocus/2, m.editFocus%2 == 0
	if i >= len(m.editKeys) {
		return m, nil
	}
	if isKey {
		m.editKeys[i], cmd = m.editKeys[i].Update(msg)
	} else {
		m.editVals[i], cmd = m.editVals[i].Update(msg)
	}
	return m, cmd
}

func (m *Model) saveEditor() (tea.Model, tea.Cmd) {
	data := map[string]interface{}{}
	for i := range m.editKeys {
		k := m.editKeys[i].Value()
		if k == "" {
			continue
		}
		data[k] = m.editVals[i].Value()
	}
	path := m.editPath
	if m.editIsNew {
		name := m.editName.Value()
		if name == "" {
			return m, m.notify(toastWarn, "secret name is required")
		}
		path = m.editPath + name
	}

	useCAS := m.a.Settings.RequireCAS && m.editMount.Kind == vault.EngineKVv2
	cas := 0
	if m.editSecret != nil {
		cas = m.editSecret.Version
	}

	m.loading = true
	mount := m.editMount
	// Deliberately NOT mutating m.editPath here: on a failed write (CAS
	// mismatch, permission denied, ...) the editor screen stays open so the
	// user can retry, and a premature mutation would double-concatenate the
	// name on a second "new secret" save attempt. writeAckMsg's handler uses
	// ack.Path — the path Write actually succeeded at — instead.
	return m, func() tea.Msg {
		ack, err := m.svc.KV.Write(m.ctx, mount, path, data, useCAS, cas)
		return writeAckMsg{ack: ack, err: err}
	}
}

// editFieldWidths splits the panel's inner width into key/value columns —
// side by side from sizeCompact up, stacked on sizeTiny.
func (m *Model) editFieldWidths(iw int) (keyColW, valColW int) {
	if m.lay.class == sizeTiny {
		return iw, iw
	}
	keyColW = iw / 3
	if keyColW < 16 {
		keyColW = 16
	}
	valColW = iw - keyColW - 2
	if valColW < 12 {
		valColW = 12
	}
	return
}

func (m *Model) viewEditor() string {
	ow, oh := m.lay.bodyW, m.lay.bodyH
	iw, _ := panelInner(ow, oh)
	tiny := m.lay.class == sizeTiny
	keyColW, valColW := m.editFieldWidths(iw)

	rows := []string{m.styles.PanelTitle.Render("Edit " + m.editMount.Path + m.editPath), ""}

	if m.editIsNew {
		label := "  name"
		if m.editFocus == -1 {
			label = m.styles.CrumbActive.Render(symChevronR + " name")
		}
		m.editName.SetWidth(max(iw-2, 8))
		rows = append(rows, label, "  "+m.editName.View(), "")
	}

	const lbl = 8 // widest label ("▸ value") is 7 cells; +1 keeps a gap before the input's own prompt
	for i := range m.editKeys {
		kFocused, vFocused := m.editFocus == 2*i, m.editFocus == 2*i+1
		kLabel, vLabel := padRight("key", lbl), padRight("value", lbl)
		if kFocused {
			kLabel = m.styles.CrumbActive.Render(padRight(symChevronR+" key", lbl))
		}
		if vFocused {
			vLabel = m.styles.CrumbActive.Render(padRight(symChevronR+" value", lbl))
		}
		m.editKeys[i].SetWidth(max(keyColW-lbl-1, 6))
		m.editVals[i].SetWidth(max(valColW-lbl-1, 6))

		keyCell := kLabel + m.editKeys[i].View()
		valCell := vLabel + m.editVals[i].View()
		if tiny {
			rows = append(rows, keyCell, valCell, "")
		} else {
			rows = append(rows, lipgloss.JoinHorizontal(lipgloss.Top, padRight(keyCell, keyColW+lbl+2), valCell))
		}
	}
	if !tiny {
		rows = append(rows, "")
	}

	return renderPanel(m.styles.PanelActive, ow, oh, lipgloss.JoinVertical(lipgloss.Left, rows...))
}