// Package ui provides the bubbletea terminal UI for wallarm:
//   - Wizard: guides new deployments (type → region → config → deploy)
//   - Dashboard: lists existing nodes with actions (add, config, remove, tunnel)
package ui

import (
	"fmt"
	"strings"
	"time"

	tea "github.com/charmbracelet/bubbletea"
	"github.com/charmbracelet/huh"
	"github.com/charmbracelet/lipgloss"

	"git.sechpoint.app/customer-engineering/wallarm/internal/docker"
	"git.sechpoint.app/customer-engineering/wallarm/internal/native"
	"git.sechpoint.app/customer-engineering/wallarm/internal/preflight"
	"git.sechpoint.app/customer-engineering/wallarm/internal/state"
)

// Styles
var (
	titleStyle  = lipgloss.NewStyle().Bold(true).Foreground(lipgloss.Color("63")).MarginBottom(1)
	goodStyle   = lipgloss.NewStyle().Foreground(lipgloss.Color("42"))
	warnStyle   = lipgloss.NewStyle().Foreground(lipgloss.Color("227"))
	badStyle    = lipgloss.NewStyle().Foreground(lipgloss.Color("196"))
	dimStyle    = lipgloss.NewStyle().Foreground(lipgloss.Color("240"))
	activeStyle = lipgloss.NewStyle().Foreground(lipgloss.Color("63")).Bold(true)
)

// Model is the top-level bubbletea model.
type Model struct {
	state    stateView
	width    int
	height   int
	status   string      // feedback message during deployment
	deploying bool       // true while deployment is in progress
}

type stateView int

const (
	viewPreflight stateView = iota
	viewRoute
	viewWizard
	viewDashboard
	viewDone
	viewError
)

var preflightResult preflight.Result

// deployCompleteMsg is sent when deployment finishes.
type deployCompleteMsg struct {
	err error
}

// Run starts the bubbletea TUI.
func Run(r preflight.Result) error {
	preflightResult = r
	m := Model{state: viewRoute}
	p := tea.NewProgram(m, tea.WithAltScreen())
	if _, err := p.Run(); err != nil {
		return err
	}
	return nil
}

func (m Model) Init() tea.Cmd { return nil }

func (m Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
	switch msg := msg.(type) {
	case tea.KeyMsg:
		switch msg.String() {
		case "q", "ctrl+c":
			return m, tea.Quit
		case "1":
			if m.state == viewWizard && !m.deploying {
				return m, m.startDeploy("docker")
			}
		case "2":
			if m.state == viewWizard && !m.deploying {
				return m, m.startDeploy("native")
			}
		case "enter":
			if m.state == viewDone || m.state == viewError {
				return m, tea.Quit
			}
		}
	case deployCompleteMsg:
		m.deploying = false
		if msg.err != nil {
			m.status = fmt.Sprintf("Deployment failed: %v", msg.err)
			m.state = viewError
		} else {
			m.status = "Deployment successful!"
			m.state = viewDone
		}
		return m, nil
	case tea.WindowSizeMsg:
		m.width = msg.Width
		m.height = msg.Height
	}

	switch m.state {
	case viewRoute:
		if state.HasDeployment() {
			m.state = viewDashboard
		} else {
			m.state = viewWizard
		}
	}
	return m, nil
}

func (m Model) View() string {
	switch m.state {
	case viewRoute:
		return ""
	case viewWizard:
		return wizardView(m)
	case viewDashboard:
		return dashboardView(m)
	case viewDone:
		return goodStyle.Render("✅ " + m.status) + "\n\n" + dimStyle.Render("Press Enter to exit.")
	case viewError:
		return badStyle.Render("❌ " + m.status) + "\n\n" + dimStyle.Render("Press Enter to exit.")
	}
	return ""
}

// startDeploy runs the Huh form in a goroutine, then calls the deploy package.
func (m Model) startDeploy(deployType string) tea.Cmd {
	return func() tea.Msg {
		m.deploying = true

		// Run the interactive form
		s, err := runDeployForm(deployType)
		if err != nil {
			return deployCompleteMsg{err}
		}

		// Execute deployment
		if deployType == "native" {
			err = deployNative(s)
		} else {
			err = deployDocker(s)
		}

		// Save state on success
		if err == nil {
			state.Save(&s)
		}

		return deployCompleteMsg{err}
	}
}

// ─── Wizard ──────────────────────────────────────────────────────────

func wizardView(m Model) string {
	s := titleStyle.Render("🛡️  Wallarm Setup Wizard") + "\n"

	if m.deploying {
		s += dimStyle.Render("Configuring deployment — follow the prompts below...") + "\n"
		return s
	}

	s += dimStyle.Render("No existing deployment found. Let's set one up.") + "\n\n"
	s += activeStyle.Render("Step 1: Choose deployment type") + "\n"
	s += "  [1] Docker  — Wallarm node as a container\n"
	s += "  [2] Native  — Wallarm node directly on this OS\n"
	s += dimStyle.Render("  Press 1 or 2 to begin") + "\n\n"

	s += activeStyle.Render("Step 2: Cloud region") + "\n"
	r := preflightResult
	if r.USReachable {
		s += goodStyle.Render("  US") + " — us1.api.wallarm.com (reachable)\n"
	} else {
		s += dimStyle.Render("  US — not reachable") + "\n"
	}
	if r.EUReachable {
		s += goodStyle.Render("  EU") + " — api.wallarm.com (reachable)\n"
	} else {
		s += dimStyle.Render("  EU — not reachable") + "\n"
	}
	s += dimStyle.Render("\nPress q to quit")

	return s
}

// runDeployForm collects configuration via huh interactive forms.
func runDeployForm(deployType string) (state.State, error) {
	var s state.State
	s.DeploymentType = deployType

	// Step 1: Cloud region
	regionOptions := []huh.Option[string]{}
	if preflightResult.USReachable {
		regionOptions = append(regionOptions, huh.NewOption("US (us1.api.wallarm.com)", "US"))
	}
	if preflightResult.EUReachable {
		regionOptions = append(regionOptions, huh.NewOption("EU (api.wallarm.com)", "EU"))
	}

	if len(regionOptions) == 0 {
		return s, fmt.Errorf("no cloud regions reachable")
	}

	var region string
	if len(regionOptions) == 1 {
		region = regionOptions[0].Value // auto-select
	} else {
		err := huh.NewForm(
			huh.NewGroup(
				huh.NewSelect[string]().
					Title("Choose Wallarm cloud region").
					Options(regionOptions...).
					Value(&region),
			),
		).WithTheme(huh.ThemeCharm()).Run()
		if err != nil {
			return s, err
		}
	}
	s.CloudRegion = region
	if region == "US" {
		s.APIHost = "us1.api.wallarm.com"
	} else {
		s.APIHost = "api.wallarm.com"
	}

	// Step 2: API Token
	var apiToken string
	err := huh.NewForm(
		huh.NewGroup(
			huh.NewInput().
				Title("Wallarm API Token (Deploy role)").
				Placeholder("Paste your token here").
				EchoMode(huh.EchoModePassword).
				Value(&apiToken).
				Validate(func(v string) error {
					if len(v) < 10 {
						return fmt.Errorf("token too short")
					}
					return nil
				}),
		),
	).WithTheme(huh.ThemeCharm()).Run()
	if err != nil {
		return s, err
	}
	s.APIToken = apiToken

	// Step 3: Node configuration
	var nodeName, address, labels string
	nodeForm := huh.NewForm(
		huh.NewGroup(
			huh.NewInput().Title("Node name").Value(&nodeName).Validate(func(v string) error {
				if v == "" {
					return fmt.Errorf("required")
				}
				return nil
			}),
		),
	)

	if deployType == "native" {
		nodeForm = huh.NewForm(
			huh.NewGroup(
				huh.NewInput().Title("Node name").Value(&nodeName).Validate(func(v string) error {
					if v == "" {
						return fmt.Errorf("required")
					}
					return nil
				}),
				huh.NewInput().Title("Listen address (IP:Port)").Placeholder("0.0.0.0:8081").Value(&address).Validate(func(v string) error {
					if v == "" {
						return fmt.Errorf("required")
					}
					return nil
				}),
				huh.NewInput().Title("Labels (optional)").Placeholder("group=prod").Value(&labels),
			),
		)
	} else {
		var upstreamIP, upstreamPortStr string
		nodeForm = huh.NewForm(
			huh.NewGroup(
				huh.NewInput().Title("Node name").Value(&nodeName).Validate(func(v string) error {
					if v == "" {
						return fmt.Errorf("required")
					}
					return nil
				}),
				huh.NewInput().Title("Ingress port").Placeholder("80").Value(&address),
				huh.NewInput().Title("Upstream IP").Placeholder("192.168.1.100").Value(&upstreamIP),
				huh.NewInput().Title("Upstream port").Placeholder("8080").Value(&upstreamPortStr),
			),
		)
		_ = upstreamIP
		_ = upstreamPortStr
	}

	err = nodeForm.WithTheme(huh.ThemeCharm()).Run()
	if err != nil {
		return s, err
	}

	s.Nodes = append(s.Nodes, state.Node{
		Name:      nodeName,
		Type:      deployType,
		Address:   address,
		Status:    "deploying",
		CreatedAt: time.Now().Format(time.RFC3339),
	})
	return s, nil
}

// deployNative executes the native deployment.
func deployNative(s state.State) error {
	if err := native.CreateNodesDir(); err != nil {
		return err
	}
	if err := native.GenerateSystemdTemplate(); err != nil {
		return err
	}
	for _, node := range s.Nodes {
		labels := "group=" + node.Name
		if err := native.InstallNode(node, s.APIToken, s.APIHost, labels); err != nil {
			return err
		}
	}
	return nil
}

// deployDocker executes the Docker deployment.
func deployDocker(s state.State) error {
	if err := docker.InstallDocker(); err != nil {
		return err
	}
	for _, node := range s.Nodes {
		if err := docker.DeployContainer(node, s.APIToken, s.APIHost); err != nil {
			return err
		}
	}
	return nil
}

// ─── Dashboard ───────────────────────────────────────────────────────

func dashboardView(m Model) string {
	s, err := state.Load()
	if err != nil || s == nil {
		return badStyle.Render("Error loading state.") + "\nPress q to quit"
	}

	out := titleStyle.Render("📊 Wallarm Dashboard") + "\n"
	out += fmt.Sprintf("Type: %s  |  Cloud: %s (%s)\n", s.DeploymentType, s.CloudRegion, s.APIHost)
	out += dimStyle.Render(strings.Repeat("─", 50)) + "\n\n"

	if len(s.Nodes) == 0 {
		out += dimStyle.Render("No nodes deployed yet.") + "\n\n"
	} else {
		out += activeStyle.Render("Nodes:") + "\n"
		for _, n := range s.Nodes {
			marker := "●"
			style := goodStyle
			if n.Status != "running" {
				marker = "○"
				style = warnStyle
			}
			detail := n.Address
			if detail == "" && n.Port != 0 {
				detail = fmt.Sprintf(":%d → %s:%d", n.Port, n.UpstreamIP, n.UpstreamPort)
			}
			out += style.Render(fmt.Sprintf("  %s %s — %s", marker, n.Name, n.Status))
			if detail != "" {
				out += dimStyle.Render(fmt.Sprintf("  (%s)", detail))
			}
			out += "\n"
		}
		out += "\n"
	}

	out += "Actions:\n"
	out += fmt.Sprintf("  %s\n", activeStyle.Render("[a] Add node"))
	out += fmt.Sprintf("  %s\n", activeStyle.Render("[c] Configure"))
	out += fmt.Sprintf("  %s\n", activeStyle.Render("[r] Remove node"))
	out += fmt.Sprintf("  %s\n", activeStyle.Render("[t] Start tunnel"))
	out += fmt.Sprintf("  %s\n", dimStyle.Render("[q] Quit"))

	return out
}