package tui

import (
	"fmt"
	"path/filepath"
	"strconv"
	"strings"

	tea "github.com/charmbracelet/bubbletea"

	"dbbackup/internal/config"
	"dbbackup/internal/logger"
)

// SettingsModel represents the settings configuration state
type SettingsModel struct {
	config   *config.Config
	logger   logger.Logger
	cursor   int
	editing  bool
	editingField string
	editingValue string
	settings []SettingItem
	quitting bool
	message  string
	parent   tea.Model
}

// SettingItem represents a configurable setting
type SettingItem struct {
	Key         string
	DisplayName string
	Value       func(*config.Config) string
	Update      func(*config.Config, string) error
	Type        string // "string", "int", "bool", "path"
	Description string
}

// Initialize settings model
func NewSettingsModel(cfg *config.Config, log logger.Logger, parent tea.Model) SettingsModel {
	settings := []SettingItem{
		{
			Key:         "backup_dir",
			DisplayName: "Backup Directory",
			Value:       func(c *config.Config) string { return c.BackupDir },
			Update: func(c *config.Config, v string) error {
				if v == "" {
					return fmt.Errorf("backup directory cannot be empty")
				}
				c.BackupDir = filepath.Clean(v)
				return nil
			},
			Type:        "path",
			Description: "Directory where backup files will be stored",
		},
		{
			Key:         "compression_level",
			DisplayName: "Compression Level",
			Value:       func(c *config.Config) string { return fmt.Sprintf("%d", c.CompressionLevel) },
			Update: func(c *config.Config, v string) error {
				val, err := strconv.Atoi(v)
				if err != nil {
					return fmt.Errorf("compression level must be a number")
				}
				if val < 0 || val > 9 {
					return fmt.Errorf("compression level must be between 0-9")
				}
				c.CompressionLevel = val
				return nil
			},
			Type:        "int",
			Description: "Compression level (0=fastest, 9=smallest)",
		},
		{
			Key:         "jobs",
			DisplayName: "Parallel Jobs",
			Value:       func(c *config.Config) string { return fmt.Sprintf("%d", c.Jobs) },
			Update: func(c *config.Config, v string) error {
				val, err := strconv.Atoi(v)
				if err != nil {
					return fmt.Errorf("jobs must be a number")
				}
				if val < 1 {
					return fmt.Errorf("jobs must be at least 1")
				}
				c.Jobs = val
				return nil
			},
			Type:        "int",
			Description: "Number of parallel jobs for backup operations",
		},
		{
			Key:         "dump_jobs",
			DisplayName: "Dump Jobs",
			Value:       func(c *config.Config) string { return fmt.Sprintf("%d", c.DumpJobs) },
			Update: func(c *config.Config, v string) error {
				val, err := strconv.Atoi(v)
				if err != nil {
					return fmt.Errorf("dump jobs must be a number")
				}
				if val < 1 {
					return fmt.Errorf("dump jobs must be at least 1")
				}
				c.DumpJobs = val
				return nil
			},
			Type:        "int",
			Description: "Number of parallel jobs for database dumps",
		},
		{
			Key:         "host",
			DisplayName: "Database Host",
			Value:       func(c *config.Config) string { return c.Host },
			Update: func(c *config.Config, v string) error {
				if v == "" {
					return fmt.Errorf("host cannot be empty")
				}
				c.Host = v
				return nil
			},
			Type:        "string",
			Description: "Database server hostname or IP address",
		},
		{
			Key:         "port",
			DisplayName: "Database Port",
			Value:       func(c *config.Config) string { return fmt.Sprintf("%d", c.Port) },
			Update: func(c *config.Config, v string) error {
				val, err := strconv.Atoi(v)
				if err != nil {
					return fmt.Errorf("port must be a number")
				}
				if val < 1 || val > 65535 {
					return fmt.Errorf("port must be between 1-65535")
				}
				c.Port = val
				return nil
			},
			Type:        "int",
			Description: "Database server port number",
		},
		{
			Key:         "user",
			DisplayName: "Database User",
			Value:       func(c *config.Config) string { return c.User },
			Update: func(c *config.Config, v string) error {
				if v == "" {
					return fmt.Errorf("user cannot be empty")
				}
				c.User = v
				return nil
			},
			Type:        "string",
			Description: "Database username for connections",
		},
		{
			Key:         "database",
			DisplayName: "Default Database",
			Value:       func(c *config.Config) string { return c.Database },
			Update: func(c *config.Config, v string) error {
				c.Database = v // Can be empty for cluster operations
				return nil
			},
			Type:        "string",
			Description: "Default database name (optional)",
		},
		{
			Key:         "ssl_mode",
			DisplayName: "SSL Mode",
			Value:       func(c *config.Config) string { return c.SSLMode },
			Update: func(c *config.Config, v string) error {
				validModes := []string{"disable", "allow", "prefer", "require", "verify-ca", "verify-full"}
				for _, mode := range validModes {
					if v == mode {
						c.SSLMode = v
						return nil
					}
				}
				return fmt.Errorf("invalid SSL mode. Valid options: %s", strings.Join(validModes, ", "))
			},
			Type:        "string",
			Description: "SSL connection mode (disable, allow, prefer, require, verify-ca, verify-full)",
		},
		{
			Key:         "auto_detect_cores",
			DisplayName: "Auto Detect CPU Cores",
			Value:       func(c *config.Config) string { 
				if c.AutoDetectCores { return "true" } else { return "false" }
			},
			Update: func(c *config.Config, v string) error {
				val, err := strconv.ParseBool(v)
				if err != nil {
					return fmt.Errorf("must be true or false")
				}
				c.AutoDetectCores = val
				return nil
			},
			Type:        "bool",
			Description: "Automatically detect and optimize for CPU cores",
		},
	}

	return SettingsModel{
		config:   cfg,
		logger:   log,
		settings: settings,
		parent:   parent,
	}
}

// Init initializes the settings model
func (m SettingsModel) Init() tea.Cmd {
	return nil
}

// Update handles messages
func (m SettingsModel) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
	switch msg := msg.(type) {
	case tea.KeyMsg:
		if m.editing {
			return m.handleEditingInput(msg)
		}
		
		switch msg.String() {
		case "ctrl+c", "q", "esc":
			m.quitting = true
			return m.parent, nil

		case "up", "k":
			if m.cursor > 0 {
				m.cursor--
			}

		case "down", "j":
			if m.cursor < len(m.settings)-1 {
				m.cursor++
			}

		case "enter", " ":
			return m.startEditing()

		case "r":
			return m.resetToDefaults()

		case "s":
			return m.saveSettings()
		}
	}

	return m, nil
}

// handleEditingInput handles input when editing a setting
func (m SettingsModel) handleEditingInput(msg tea.KeyMsg) (tea.Model, tea.Cmd) {
	switch msg.String() {
	case "ctrl+c":
		m.quitting = true
		return m.parent, nil
		
	case "esc":
		m.editing = false
		m.editingField = ""
		m.editingValue = ""
		m.message = ""
		return m, nil
		
	case "enter":
		return m.saveEditedValue()
		
	case "backspace":
		if len(m.editingValue) > 0 {
			m.editingValue = m.editingValue[:len(m.editingValue)-1]
		}
		
	default:
		// Add character to editing value
		if len(msg.String()) == 1 {
			m.editingValue += msg.String()
		}
	}
	
	return m, nil
}

// startEditing begins editing a setting
func (m SettingsModel) startEditing() (tea.Model, tea.Cmd) {
	if m.cursor >= len(m.settings) {
		return m, nil
	}
	
	setting := m.settings[m.cursor]
	m.editing = true
	m.editingField = setting.Key
	m.editingValue = setting.Value(m.config)
	m.message = ""
	
	return m, nil
}

// saveEditedValue saves the currently edited value
func (m SettingsModel) saveEditedValue() (tea.Model, tea.Cmd) {
	if m.editingField == "" {
		return m, nil
	}
	
	// Find the setting being edited
	var setting *SettingItem
	for i := range m.settings {
		if m.settings[i].Key == m.editingField {
			setting = &m.settings[i]
			break
		}
	}
	
	if setting == nil {
		m.message = errorStyle.Render("❌ Setting not found")
		m.editing = false
		return m, nil
	}
	
	// Update the configuration
	if err := setting.Update(m.config, m.editingValue); err != nil {
		m.message = errorStyle.Render(fmt.Sprintf("❌ %s", err.Error()))
		return m, nil
	}
	
	m.message = successStyle.Render(fmt.Sprintf("✅ Updated %s", setting.DisplayName))
	m.editing = false
	m.editingField = ""
	m.editingValue = ""
	
	return m, nil
}

// resetToDefaults resets configuration to default values
func (m SettingsModel) resetToDefaults() (tea.Model, tea.Cmd) {
	newConfig := config.New()
	
	// Copy important connection details
	newConfig.Host = m.config.Host
	newConfig.Port = m.config.Port
	newConfig.User = m.config.User
	newConfig.Database = m.config.Database
	newConfig.DatabaseType = m.config.DatabaseType
	
	*m.config = *newConfig
	m.message = successStyle.Render("✅ Settings reset to defaults")
	
	return m, nil
}

// saveSettings validates and saves current settings
func (m SettingsModel) saveSettings() (tea.Model, tea.Cmd) {
	if err := m.config.Validate(); err != nil {
		m.message = errorStyle.Render(fmt.Sprintf("❌ Validation failed: %s", err.Error()))
		return m, nil
	}
	
	// Optimize CPU settings if auto-detect is enabled
	if m.config.AutoDetectCores {
		if err := m.config.OptimizeForCPU(); err != nil {
			m.message = errorStyle.Render(fmt.Sprintf("❌ CPU optimization failed: %s", err.Error()))
			return m, nil
		}
	}
	
	m.message = successStyle.Render("✅ Settings validated and saved")
	return m, nil
}

// View renders the settings interface
func (m SettingsModel) View() string {
	if m.quitting {
		return "Returning to main menu...\n"
	}

	var b strings.Builder

	// Header
	header := titleStyle.Render("⚙️  Configuration Settings")
	b.WriteString(fmt.Sprintf("\n%s\n\n", header))

	// Settings list
	for i, setting := range m.settings {
		cursor := " "
		value := setting.Value(m.config)
		
		if m.cursor == i {
			cursor = ">"
			if m.editing && m.editingField == setting.Key {
				// Show editing interface
				editValue := m.editingValue
				if setting.Type == "bool" {
					editValue += " (true/false)"
				}
				line := fmt.Sprintf("%s %s: %s", cursor, setting.DisplayName, editValue)
				b.WriteString(selectedStyle.Render(line))
				b.WriteString(" ✏️")
			} else {
				line := fmt.Sprintf("%s %s: %s", cursor, setting.DisplayName, value)
				b.WriteString(selectedStyle.Render(line))
			}
		} else {
			line := fmt.Sprintf("%s %s: %s", cursor, setting.DisplayName, value)
			b.WriteString(menuStyle.Render(line))
		}
		b.WriteString("\n")
		
		// Show description for selected item
		if m.cursor == i && !m.editing {
			desc := detailStyle.Render(fmt.Sprintf("    %s", setting.Description))
			b.WriteString(desc)
			b.WriteString("\n")
		}
	}

	// Message area
	if m.message != "" {
		b.WriteString("\n")
		b.WriteString(m.message)
		b.WriteString("\n")
	}

	// Current configuration summary
	if !m.editing {
		b.WriteString("\n")
		b.WriteString(infoStyle.Render("📋 Current Configuration:"))
		b.WriteString("\n")
		
		summary := []string{
			fmt.Sprintf("Database: %s@%s:%d", m.config.User, m.config.Host, m.config.Port),
			fmt.Sprintf("Backup Dir: %s", m.config.BackupDir),
			fmt.Sprintf("Compression: Level %d", m.config.CompressionLevel),
			fmt.Sprintf("Jobs: %d parallel, %d dump", m.config.Jobs, m.config.DumpJobs),
		}
		
		for _, line := range summary {
			b.WriteString(detailStyle.Render(fmt.Sprintf("  %s", line)))
			b.WriteString("\n")
		}
	}

	// Footer with instructions
	var footer string
	if m.editing {
		footer = infoStyle.Render("\n⌨️  Type new value • Enter to save • Esc to cancel")
	} else {
		footer = infoStyle.Render("\n⌨️  ↑/↓ navigate • Enter to edit • 's' save • 'r' reset • 'q' back to menu")
	}
	b.WriteString(footer)

	return b.String()
}

// RunSettingsMenu starts the settings configuration interface
func RunSettingsMenu(cfg *config.Config, log logger.Logger, parent tea.Model) error {
	m := NewSettingsModel(cfg, log, parent)
	p := tea.NewProgram(m, tea.WithAltScreen())
	
	if _, err := p.Run(); err != nil {
		return fmt.Errorf("error running settings menu: %w", err)
	}
	
	return nil
}