package app

import (
	"strings"

	tea "charm.land/bubbletea/v2"
	"charm.land/lipgloss/v2"
	"github.com/correx/tui-go/internal/protocol"
)

// openConfig opens the config editor and requests the current config from the server.
func (m *Model) openConfig() {
	m.overlay = OverlayConfig
	m.configIndex = 0
	m.configEditing = false
	m.configEditBuf = ""
	m.configError = ""
	if len(m.configFields) == 0 {
		m.configLoading = true
	}
	m.client.Send(protocol.GetConfig())
}

// handleConfigKey owns every key while the config overlay is open. In edit mode it captures the
// value being typed; otherwise it navigates fields, stages edits, and saves.
func (m Model) handleConfigKey(k keyMsg) (tea.Model, tea.Cmd) {
	if m.configEditing {
		switch k.Type {
		case keyEsc:
			m.configEditing = false
			m.configEditBuf = ""
		case keyEnter:
			if m.configIndex >= 0 && m.configIndex < len(m.configFields) {
				m.configStaged[m.configFields[m.configIndex].Key] = m.configEditBuf
			}
			m.configEditing = false
			m.configEditBuf = ""
		case keyBackspace:
			if n := len(m.configEditBuf); n > 0 {
				m.configEditBuf = m.configEditBuf[:n-1]
			}
		case keyRunes, keySpace:
			m.configEditBuf += string(k.Runes)
		}
		return m, nil
	}

	switch {
	case k.Type == keyEsc || runeIs(k, "g"):
		m.overlay = OverlayNone
	case k.Type == keyUp || runeIs(k, "k"):
		if m.configIndex > 0 {
			m.configIndex--
		}
	case k.Type == keyDown || runeIs(k, "j"):
		if m.configIndex < len(m.configFields)-1 {
			m.configIndex++
		}
	case k.Type == keyEnter || k.Type == keySpace:
		m = m.actOnConfigField()
	case runeIs(k, "s"):
		if len(m.configStaged) > 0 {
			m.client.Send(protocol.UpdateConfig(m.configStaged))
		}
	}
	return m, nil
}

// actOnConfigField applies the type-appropriate action to the selected field: toggle a bool,
// cycle an enum, or begin inline editing for numeric/string fields.
func (m Model) actOnConfigField() Model {
	if m.configIndex < 0 || m.configIndex >= len(m.configFields) {
		return m
	}
	f := m.configFields[m.configIndex]
	switch f.Type {
	case "BOOL":
		if m.currentConfigValue(f) == "true" {
			m.configStaged[f.Key] = "false"
		} else {
			m.configStaged[f.Key] = "true"
		}
	case "ENUM":
		m.configStaged[f.Key] = cycleEnum(f.Options, m.currentConfigValue(f))
	default: // INT, LONG, DOUBLE, STRING
		m.configEditing = true
		m.configEditBuf = m.currentConfigValue(f)
	}
	return m
}

// currentConfigValue returns the staged edit for a field if present, else the server value.
func (m Model) currentConfigValue(f protocol.ConfigFieldDto) string {
	if v, ok := m.configStaged[f.Key]; ok {
		return v
	}
	return f.Value
}

// cycleEnum returns the option after cur (wrapping); falls back to the first option.
func cycleEnum(options []string, cur string) string {
	if len(options) == 0 {
		return cur
	}
	for i, o := range options {
		if o == cur {
			return options[(i+1)%len(options)]
		}
	}
	return options[0]
}

func (m Model) configModal() string {
	t := m.theme
	w := m.modalWidth()

	var b strings.Builder
	b.WriteString(m.titleLine("config"))
	if n := len(m.configStaged); n > 0 {
		b.WriteString(mbg(t, "   ("+itoa(n)+" unsaved)", t.P.Warn))
	}
	b.WriteString("\n\n")

	if m.configLoading && len(m.configFields) == 0 {
		b.WriteString(mbg(t, "  loading…", t.P.Faint) + "\n")
		b.WriteString("\n" + modalHints(t, [][2]string{{"esc", "close"}}))
		return t.Overlay.Width(w).Render(b.String())
	}
	if m.configError != "" {
		b.WriteString(lipgloss.NewStyle().Foreground(t.P.Bad).Background(t.P.BgPanel).Render("  ▲ "+truncate(m.configError, w-8)) + "\n\n")
	}
	if len(m.configRestart) > 0 {
		b.WriteString(mbg(t, "  saved · restart required: "+strings.Join(m.configRestart, ", "), t.P.Warn) + "\n\n")
	}

	// Windowed field list, keeping the selected row in view.
	bodyH := m.height*70/100 - 6
	if bodyH < 4 {
		bodyH = 4
	}
	off := 0
	if len(m.configFields) > bodyH {
		off = m.configIndex - bodyH/2
		if off < 0 {
			off = 0
		}
		if off > len(m.configFields)-bodyH {
			off = len(m.configFields) - bodyH
		}
	}
	end := off + bodyH
	if end > len(m.configFields) {
		end = len(m.configFields)
	}
	for i := off; i < end; i++ {
		b.WriteString(m.configRow(i) + "\n")
	}

	b.WriteString("\n" + modalHints(t, [][2]string{
		{"↑↓", "select"}, {"enter", "edit/toggle"}, {"s", "save"}, {"g/esc", "close"},
	}))
	return t.Overlay.Width(w).Render(b.String())
}

// configRow renders one field line: marker, key, current value (with edit caret / staged mark).
func (m Model) configRow(i int) string {
	t := m.theme
	f := m.configFields[i]
	_, staged := m.configStaged[f.Key]

	marker := mbg(t, "  ", t.P.BgPanel)
	keyFg := t.P.Fg
	if i == m.configIndex {
		marker = lipgloss.NewStyle().Foreground(t.P.Accent).Background(t.P.BgPanel).Render("▸ ")
		keyFg = t.P.FgStrong
	}

	var valStr string
	if m.configEditing && i == m.configIndex {
		caret := lipgloss.NewStyle().Foreground(t.P.Accent).Background(t.P.BgPanel).Render("▏")
		valStr = lipgloss.NewStyle().Foreground(t.P.FgStrong).Background(t.P.BgPanel).Render(m.configEditBuf) + caret
	} else {
		valFg := t.P.Accent2
		if staged {
			valFg = t.P.Warn
		}
		val := m.currentConfigValue(f)
		if staged {
			val = "*" + val
		}
		valStr = lipgloss.NewStyle().Foreground(valFg).Background(t.P.BgPanel).Render(val)
	}

	row := marker +
		lipgloss.NewStyle().Foreground(keyFg).Background(t.P.BgPanel).Render(padRaw(f.Key, 42)) + " " + valStr
	if f.RestartRequired {
		row += lipgloss.NewStyle().Foreground(t.P.Faint).Background(t.P.BgPanel).Render("  (restart)")
	}
	return row
}
