package tui

import (
	"fmt"
	"sort"
	"time"

	"punchcard/internal/queries"

	tea "github.com/charmbracelet/bubbletea"
	"github.com/charmbracelet/lipgloss/v2"
)

// NewHistoryBoxModel creates a new history box model
func NewHistoryBoxModel() HistoryBoxModel {
	return HistoryBoxModel{
		viewLevel:     HistoryLevelSummary,
		selectedIndex: 0,
	}
}

// Update handles messages for the history box
func (m HistoryBoxModel) Update(msg tea.Msg) (HistoryBoxModel, tea.Cmd) {
	return m, nil
}

// View renders the history box
func (m HistoryBoxModel) View(width, height int, isSelected bool) string {
	var content string
	var title string
	
	if len(m.entries) == 0 {
		content = "No recent entries\n\nStart tracking time to\nsee your history here."
		title = "📝 Recent History"
	} else {
		if m.viewLevel == HistoryLevelDetails && m.selectedSummaryItem != nil {
			// Details view
			title = fmt.Sprintf("📝 Details: %s", m.formatSummaryTitle(*m.selectedSummaryItem))
			content = m.renderDetailsView()
		} else {
			// Summary view
			title = "📝 Recent History"
			content = m.renderSummaryView()
		}
	}
	
	// Apply box styling
	style := unselectedBoxStyle
	if isSelected {
		style = selectedBoxStyle
	}
	
	return style.Width(width).Height(height).Render(
		fmt.Sprintf("%s\n\n%s", title, content),
	)
}

// renderSummaryView renders the summary view (level 1) with date headers and client/project summaries
func (m HistoryBoxModel) renderSummaryView() string {
	var content string
	displayItems := m.getDisplayItems()
	
	if len(displayItems) == 0 {
		return "No recent entries found."
	}
	
	// Find a valid selected index for rendering (don't modify the model)
	selectedIndex := m.selectedIndex
	if selectedIndex < 0 || selectedIndex >= len(displayItems) || !displayItems[selectedIndex].IsSelectable {
		// Find the first selectable item for display purposes
		for i, item := range displayItems {
			if item.IsSelectable {
				selectedIndex = i
				break
			}
		}
	}
	
	for i, item := range displayItems {
		var itemStyle lipgloss.Style
		var line string
		
		switch item.Type {
		case HistoryItemDateHeader:
			// Date header
			line = *item.DateHeader
			itemStyle = lipgloss.NewStyle().Bold(true).Foreground(lipgloss.Color("3"))
			
		case HistoryItemSummary:
			// Summary item
			summary := item.Summary
			clientProject := m.formatSummaryTitle(*summary)
			line = fmt.Sprintf("  %s (%s)", clientProject, FormatDuration(summary.TotalDuration))
			
			// Highlight if selected
			if item.IsSelectable && selectedIndex == i {
				itemStyle = lipgloss.NewStyle().Background(lipgloss.Color("62")).Foreground(lipgloss.Color("230"))
			} else {
				itemStyle = lipgloss.NewStyle()
			}
		}
		
		content += itemStyle.Render(line) + "\n"
	}
	
	return content
}

// renderDetailsView renders the details view (level 2) showing individual entries
func (m HistoryBoxModel) renderDetailsView() string {
	var content string
	
	if len(m.detailsEntries) == 0 {
		return "No entries found for this selection."
	}
	
	for i, entry := range m.detailsEntries {
		// Calculate duration
		var duration time.Duration
		if entry.EndTime.Valid {
			duration = entry.EndTime.Time.Sub(entry.StartTime)
		} else {
			// Active entry - use cached running timer data if available
			if m.runningTimerStart != nil {
				duration = time.Since(*m.runningTimerStart)
			} else {
				// Fallback to entry start time if cache not available
				duration = time.Since(entry.StartTime)
			}
		}
		
		// Format time range
		startTime := entry.StartTime.Local().Format("3:04 PM")
		var timeRange string
		if entry.EndTime.Valid {
			endTime := entry.EndTime.Time.Local().Format("3:04 PM")
			timeRange = fmt.Sprintf("%s - %s", startTime, endTime)
		} else {
			timeRange = fmt.Sprintf("%s - now", startTime)
		}
		
		// Entry line
		entryLine := fmt.Sprintf("%s (%s)", timeRange, FormatDuration(duration))
		
		// Apply selection highlighting
		entryStyle := lipgloss.NewStyle()
		if m.selectedIndex == i {
			entryStyle = entryStyle.Background(lipgloss.Color("62")).Foreground(lipgloss.Color("230"))
		}
		
		// Also highlight active entries differently
		if !entry.EndTime.Valid {
			if m.selectedIndex == i {
				// Selected active entry
				entryStyle = entryStyle.Background(lipgloss.Color("196")).Foreground(lipgloss.Color("230"))
			} else {
				// Non-selected active entry
				entryStyle = activeTimerStyle
			}
		}
		
		content += entryStyle.Render(entryLine) + "\n"
		
		// Description if available
		if entry.Description.Valid && entry.Description.String != "" {
			descStyle := lipgloss.NewStyle()
			if m.selectedIndex == i {
				descStyle = descStyle.Background(lipgloss.Color("62")).Foreground(lipgloss.Color("230"))
			}
			content += descStyle.Render(fmt.Sprintf("  \"%s\"", entry.Description.String)) + "\n"
		}
		
		// Add spacing between entries
		if i < len(m.detailsEntries)-1 {
			content += "\n"
		}
	}
	
	return content
}

// formatSummaryTitle creates a display title for a summary item
func (m HistoryBoxModel) formatSummaryTitle(summary HistorySummaryItem) string {
	var title string
	if summary.ClientName != "" {
		title = summary.ClientName
	} else {
		title = fmt.Sprintf("Client %d", summary.ClientID)
	}
	
	if summary.ProjectID != nil {
		if summary.ProjectName != nil && *summary.ProjectName != "" {
			title += fmt.Sprintf(" / %s", *summary.ProjectName)
		} else {
			title += fmt.Sprintf(" / Project %d", *summary.ProjectID)
		}
	}
	
	return title
}

// UpdateEntries updates the history entries and regenerates summary data
func (m HistoryBoxModel) UpdateEntries(entries []queries.TimeEntry) HistoryBoxModel {
	m.entries = entries
	// Reset view to summary level
	m.viewLevel = HistoryLevelSummary
	m.selectedSummaryItem = nil
	// Regenerate summary data
	m.summaryItems = m.generateSummaryItems(entries)
	// Ensure we have a valid selection pointing to a selectable item
	m.selectedIndex = 0
	m = m.ensureValidSelection()
	return m
}

// UpdateData updates the history entries along with client and project data for name lookups
func (m HistoryBoxModel) UpdateData(entries []queries.TimeEntry, clients []queries.Client, projects []queries.ListAllProjectsRow) HistoryBoxModel {
	m.entries = entries
	m.clients = clients
	m.projects = projects
	// Reset view to summary level
	m.viewLevel = HistoryLevelSummary
	m.selectedSummaryItem = nil
	// Regenerate summary data with the new client/project data
	m.summaryItems = m.generateSummaryItems(entries)
	// Ensure we have a valid selection pointing to a selectable item
	m.selectedIndex = 0
	m = m.ensureValidSelection()
	return m
}

// NextSelection moves to the next selectable row
func (m HistoryBoxModel) NextSelection() HistoryBoxModel {
	displayItems := m.getDisplayItems()
	if len(displayItems) == 0 {
		return m
	}
	
	// Ensure current selection is valid
	m = m.ensureValidSelection()
	
	// Find next selectable item
	for i := m.selectedIndex + 1; i < len(displayItems); i++ {
		if displayItems[i].IsSelectable {
			m.selectedIndex = i
			break
		}
	}
	
	return m
}

// PrevSelection moves to the previous selectable row
func (m HistoryBoxModel) PrevSelection() HistoryBoxModel {
	displayItems := m.getDisplayItems()
	if len(displayItems) == 0 {
		return m
	}
	
	// Ensure current selection is valid
	m = m.ensureValidSelection()
	
	// Find previous selectable item
	for i := m.selectedIndex - 1; i >= 0; i-- {
		if displayItems[i].IsSelectable {
			m.selectedIndex = i
			break
		}
	}
	
	return m
}

// ensureValidSelection ensures the selected index points to a valid selectable item
func (m HistoryBoxModel) ensureValidSelection() HistoryBoxModel {
	displayItems := m.getDisplayItems()
	if len(displayItems) == 0 {
		m.selectedIndex = 0
		return m
	}
	
	// If current selection is valid and selectable, keep it
	if m.selectedIndex >= 0 && m.selectedIndex < len(displayItems) && displayItems[m.selectedIndex].IsSelectable {
		return m
	}
	
	// Find the first selectable item
	for i, item := range displayItems {
		if item.IsSelectable {
			m.selectedIndex = i
			break
		}
	}
	
	return m
}

// GetSelectedEntry returns the currently selected entry
func (m HistoryBoxModel) GetSelectedEntry() *queries.TimeEntry {
	if m.viewLevel == HistoryLevelDetails {
		if m.selectedIndex >= 0 && m.selectedIndex < len(m.detailsEntries) {
			return &m.detailsEntries[m.selectedIndex]
		}
	} else {
		if m.selectedIndex >= 0 && m.selectedIndex < len(m.entries) {
			return &m.entries[m.selectedIndex]
		}
	}
	return nil
}

// generateSummaryItems creates summary items grouped by date and client/project
func (m HistoryBoxModel) generateSummaryItems(entries []queries.TimeEntry) []HistorySummaryItem {
	// Group entries by date and client/project combination
	groupMap := make(map[string]*HistorySummaryItem)
	
	for _, entry := range entries {
		// Get the date (year-month-day only)
		date := entry.StartTime.Truncate(24 * time.Hour)
		
		// Create a key for grouping
		key := fmt.Sprintf("%s-%d", date.Format("2006-01-02"), entry.ClientID)
		if entry.ProjectID.Valid {
			key += fmt.Sprintf("-%d", entry.ProjectID.Int64)
		}
		
		// Calculate duration for this entry
		var duration time.Duration
		if entry.EndTime.Valid {
			duration = entry.EndTime.Time.Sub(entry.StartTime)
		} else {
			// Active entry - use cached running timer data if available
			if m.runningTimerStart != nil {
				duration = time.Since(*m.runningTimerStart)
			} else {
				// Fallback to entry start time if cache not available
				duration = time.Since(entry.StartTime)
			}
		}
		
		// Add to or update existing group
		if existing, exists := groupMap[key]; exists {
			existing.TotalDuration += duration
			existing.EntryCount++
		} else {
			// Create new summary item
			item := &HistorySummaryItem{
				Date:          date,
				ClientID:      entry.ClientID,
				ClientName:    m.lookupClientName(entry.ClientID),
				TotalDuration: duration,
				EntryCount:    1,
			}
			
			if entry.ProjectID.Valid {
				projectID := entry.ProjectID.Int64
				item.ProjectID = &projectID
				projectName := m.lookupProjectName(projectID)
				item.ProjectName = &projectName
			}
			
			groupMap[key] = item
		}
	}
	
	// Convert map to slice and sort by date (descending) then by client name
	var items []HistorySummaryItem
	for _, item := range groupMap {
		items = append(items, *item)
	}
	
	sort.Slice(items, func(i, j int) bool {
		// Sort by date descending, then by client name ascending
		if !items[i].Date.Equal(items[j].Date) {
			return items[i].Date.After(items[j].Date)
		}
		return items[i].ClientName < items[j].ClientName
	})
	
	return items
}

// lookupClientName finds the client name by ID
func (m HistoryBoxModel) lookupClientName(clientID int64) string {
	for _, client := range m.clients {
		if client.ID == clientID {
			return client.Name
		}
	}
	return fmt.Sprintf("Client %d", clientID) // Fallback if not found
}

// lookupProjectName finds the project name by ID
func (m HistoryBoxModel) lookupProjectName(projectID int64) string {
	for _, project := range m.projects {
		if project.ID == projectID {
			return project.Name
		}
	}
	return fmt.Sprintf("Project %d", projectID) // Fallback if not found
}

// DrillDown drills down into the selected summary item
func (m HistoryBoxModel) DrillDown() HistoryBoxModel {
	if m.viewLevel != HistoryLevelSummary {
		return m
	}
	
	// Get the selected summary item
	displayItems := m.getDisplayItems()
	if m.selectedIndex >= 0 && m.selectedIndex < len(displayItems) {
		item := displayItems[m.selectedIndex]
		if item.Type == HistoryItemSummary && item.Summary != nil {
			// Switch to details view
			m.viewLevel = HistoryLevelDetails
			m.selectedSummaryItem = item.Summary
			m.selectedIndex = 0
			
			// Filter entries for this date/client/project combination
			m.detailsEntries = m.getEntriesForSummaryItem(*item.Summary)
		}
	}
	
	return m
}

// GoBack goes back to summary view from details view
func (m HistoryBoxModel) GoBack() HistoryBoxModel {
	if m.viewLevel == HistoryLevelDetails {
		m.viewLevel = HistoryLevelSummary
		m.selectedSummaryItem = nil
		m.selectedIndex = 0
		m.detailsEntries = nil
		// Ensure we have a valid selection pointing to a selectable item
		m = m.ensureValidSelection()
	}
	return m
}

// getEntriesForSummaryItem returns all entries that match the given summary item
func (m HistoryBoxModel) getEntriesForSummaryItem(summary HistorySummaryItem) []queries.TimeEntry {
	var matchingEntries []queries.TimeEntry
	
	for _, entry := range m.entries {
		// Check if entry matches the summary item criteria
		entryDate := entry.StartTime.Truncate(24 * time.Hour)
		if !entryDate.Equal(summary.Date) {
			continue
		}
		
		if entry.ClientID != summary.ClientID {
			continue
		}
		
		// Check project ID match
		if summary.ProjectID == nil && entry.ProjectID.Valid {
			continue
		}
		if summary.ProjectID != nil && (!entry.ProjectID.Valid || entry.ProjectID.Int64 != *summary.ProjectID) {
			continue
		}
		
		matchingEntries = append(matchingEntries, entry)
	}
	
	// Sort by start time descending (most recent first)
	sort.Slice(matchingEntries, func(i, j int) bool {
		return matchingEntries[i].StartTime.After(matchingEntries[j].StartTime)
	})
	
	return matchingEntries
}

// getDisplayItems returns the items to display based on current view level
func (m HistoryBoxModel) getDisplayItems() []HistoryDisplayItem {
	if m.viewLevel == HistoryLevelDetails {
		// Details view - show individual entries
		var items []HistoryDisplayItem
		for _, entry := range m.detailsEntries {
			entryCopy := entry
			items = append(items, HistoryDisplayItem{
				Type:         HistoryItemEntry,
				Entry:        &entryCopy,
				IsSelectable: true,
			})
		}
		return items
	} else {
		// Summary view - show date headers and summary items
		var items []HistoryDisplayItem
		var currentDate *time.Time
		
		for _, summary := range m.summaryItems {
			// Add date header if this is a new date
			if currentDate == nil || !currentDate.Equal(summary.Date) {
				dateStr := summary.Date.Format("Monday, January 2, 2006")
				items = append(items, HistoryDisplayItem{
					Type:         HistoryItemDateHeader,
					DateHeader:   &dateStr,
					IsSelectable: false,
				})
				currentDate = &summary.Date
			}
			
			// Add summary item
			summaryCopy := summary
			items = append(items, HistoryDisplayItem{
				Type:         HistoryItemSummary,
				Summary:      &summaryCopy,
				IsSelectable: true,
			})
		}
		
		return items
	}
}