package tui

import (
	"strings"

	tea "github.com/charmbracelet/bubbletea"
)

// Tab represents a single tab in the TUI
type Tab interface {
	Init() tea.Cmd
	Update(tea.Msg) (Tab, tea.Cmd)
	View() string
	Name() string
	// Close is called when the tab is removed; implement for cleanup (e.g. disconnect SSH)
	Close()
}

// TabManager manages multiple tabs
type TabManager struct {
	tabs   []Tab
	active int
	width  int
	height int
}

// NewTabManager creates a new TabManager with an initial tab
func NewTabManager(initial Tab) *TabManager {
	return &TabManager{
		tabs:   []Tab{initial},
		active: 0,
	}
}

// Active returns the currently active tab
func (tm *TabManager) Active() Tab {
	if len(tm.tabs) == 0 {
		return nil
	}
	return tm.tabs[tm.active]
}

// Add adds a new tab, switches to it, and returns its init command
func (tm *TabManager) Add(tab Tab) tea.Cmd {
	tm.tabs = append(tm.tabs, tab)
	tm.active = len(tm.tabs) - 1

	// Forward current terminal size so new tabs know their dimensions
	if tm.width > 0 && tm.height > 0 {
		updated, _ := tab.Update(tea.WindowSizeMsg{Width: tm.width, Height: tm.height})
		tm.tabs[tm.active] = updated
	}

	return tab.Init()
}

// Close removes the tab at index and returns the active tab
func (tm *TabManager) Close(index int) Tab {
	if index < 0 || index >= len(tm.tabs) {
		return nil
	}

	// Call Close for cleanup (e.g. disconnect SSH)
	tm.tabs[index].Close()

	tm.tabs = append(tm.tabs[:index], tm.tabs[index+1:]...)

	if len(tm.tabs) == 0 {
		return nil
	}

	if tm.active >= len(tm.tabs) {
		tm.active = len(tm.tabs) - 1
	}
	return tm.tabs[tm.active]
}

// CloseActive closes the active tab
func (tm *TabManager) CloseActive() Tab {
	if len(tm.tabs) <= 1 {
		return nil
	}
	return tm.Close(tm.active)
}

// Next switches to the next tab
func (tm *TabManager) Next() {
	if len(tm.tabs) <= 1 {
		return
	}
	tm.active = (tm.active + 1) % len(tm.tabs)
}

// Prev switches to the previous tab
func (tm *TabManager) Prev() {
	if len(tm.tabs) <= 1 {
		return
	}
	tm.active--
	if tm.active < 0 {
		tm.active = len(tm.tabs) - 1
	}
}

// Len returns the number of tabs
func (tm *TabManager) Len() int {
	return len(tm.tabs)
}

// SetSize updates the terminal size for the tab manager
func (tm *TabManager) SetSize(width, height int) {
	tm.width = width
	tm.height = height
}

// Init initializes all tabs
func (tm *TabManager) Init() tea.Cmd {
	var cmds []tea.Cmd
	for _, t := range tm.tabs {
		if cmd := t.Init(); cmd != nil {
			cmds = append(cmds, cmd)
		}
	}
	return tea.Batch(cmds...)
}

// Update sends a message to the active tab
func (tm *TabManager) Update(msg tea.Msg) (tea.Cmd, error) {
	if len(tm.tabs) == 0 {
		return nil, nil
	}

	// Handle tab-level keys
	if keyMsg, ok := msg.(tea.KeyMsg); ok {
		switch keyMsg.String() {
		case "ctrl+tab":
			tm.Next()
			return nil, nil
		case "shift+tab":
			tm.Prev()
			return nil, nil
		case "ctrl+q":
			if closed := tm.CloseActive(); closed != nil {
				return nil, nil
			}
		}
	}

	// Handle window resize — forward to ALL tabs
	if wsMsg, ok := msg.(tea.WindowSizeMsg); ok {
		tm.SetSize(wsMsg.Width, wsMsg.Height)
		for i, t := range tm.tabs {
			updated, _ := t.Update(msg)
			tm.tabs[i] = updated
		}
		return nil, nil
	}

	updated, cmd := tm.tabs[tm.active].Update(msg)
	tm.tabs[tm.active] = updated
	return cmd, nil
}

// View renders the tab bar and active tab content
func (tm *TabManager) View() string {
	if len(tm.tabs) == 0 {
		return ""
	}

	var b strings.Builder

	// Render tab bar
	b.WriteString(renderTabBar(tm))

	// Render active tab content
	content := tm.tabs[tm.active].View()
	if content != "" {
		b.WriteString("\n")
		b.WriteString(content)
	}

	return b.String()
}

// renderTabBar renders the top tab bar
func renderTabBar(tm *TabManager) string {
	if len(tm.tabs) == 0 {
		return ""
	}

	var cells []string
	for i, tab := range tm.tabs {
		name := tab.Name()
		if i == tm.active {
			cells = append(cells, TabActiveStyle.Render(name))
		} else {
			cells = append(cells, TabInactiveStyle.Render(name))
		}
	}

	bar := strings.Join(cells, "")
	return TabBarStyle.Render(bar)
}