package timestampeditor

import (
	"log/slog"
	"strings"
	"tasksquire/common"
	"time"

	"github.com/charmbracelet/bubbles/key"
	tea "github.com/charmbracelet/bubbletea"
	"github.com/charmbracelet/lipgloss"
)

const (
	timeFormat = "20060102T150405Z" // Timewarrior format
)

// Field represents which field is currently focused
type Field int

const (
	TimeField Field = iota
	DateField
)

// TimestampEditor is a component for editing timestamps with separate time and date fields
type TimestampEditor struct {
	common *common.Common

	// Current timestamp value
	timestamp time.Time
	isEmpty   bool // Track if timestamp is unset

	// UI state
	focused      bool
	currentField Field

	// Dimensions
	width  int
	height int

	// Title and description
	title       string
	description string

	// Validation
	validate func(time.Time) error
	err      error
}

// New creates a new TimestampEditor with no initial timestamp
func New(com *common.Common) *TimestampEditor {
	return &TimestampEditor{
		common:       com,
		timestamp:    time.Time{}, // Zero time
		isEmpty:      true,        // Start empty
		focused:      false,
		currentField: TimeField,
		validate:     func(time.Time) error { return nil },
	}
}

// Title sets the title of the timestamp editor
func (t *TimestampEditor) Title(title string) *TimestampEditor {
	t.title = title
	return t
}

// Description sets the description of the timestamp editor
func (t *TimestampEditor) Description(description string) *TimestampEditor {
	t.description = description
	return t
}

// Value sets the initial timestamp value
func (t *TimestampEditor) Value(timestamp time.Time) *TimestampEditor {
	t.timestamp = timestamp
	t.isEmpty = timestamp.IsZero()
	return t
}

// ValueFromString sets the initial timestamp from a timewarrior format string
func (t *TimestampEditor) ValueFromString(s string) *TimestampEditor {
	if s == "" {
		t.timestamp = time.Time{}
		t.isEmpty = true
		return t
	}

	parsed, err := time.Parse(timeFormat, s)
	if err != nil {
		slog.Error("Failed to parse timestamp", "error", err)
		t.timestamp = time.Time{}
		t.isEmpty = true
		return t
	}

	t.timestamp = parsed.Local()
	t.isEmpty = false
	return t
}

// GetValue returns the current timestamp
func (t *TimestampEditor) GetValue() time.Time {
	return t.timestamp
}

// GetValueString returns the timestamp in timewarrior format, or empty string if unset
func (t *TimestampEditor) GetValueString() string {
	if t.isEmpty {
		return ""
	}
	return t.timestamp.UTC().Format(timeFormat)
}

// Validate sets the validation function
func (t *TimestampEditor) Validate(validate func(time.Time) error) *TimestampEditor {
	t.validate = validate
	return t
}

// Error returns the validation error
func (t *TimestampEditor) Error() error {
	return t.err
}

// Focus focuses the timestamp editor
func (t *TimestampEditor) Focus() tea.Cmd {
	t.focused = true
	return nil
}

// Blur blurs the timestamp editor
func (t *TimestampEditor) Blur() tea.Cmd {
	t.focused = false
	t.err = t.validate(t.timestamp)
	return nil
}

// SetSize sets the size of the timestamp editor
func (t *TimestampEditor) SetSize(width, height int) {
	t.width = width
	t.height = height
}

// Init initializes the timestamp editor
func (t *TimestampEditor) Init() tea.Cmd {
	return nil
}

// Update handles messages for the timestamp editor
func (t *TimestampEditor) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
	if !t.focused {
		return t, nil
	}

	switch msg := msg.(type) {
	case tea.KeyMsg:
		t.err = nil

		switch msg.String() {
		// Navigation between fields
		case "h", "left":
			t.currentField = TimeField
		case "l", "right":
			t.currentField = DateField

		// Time field adjustments (lowercase - 5 minutes)
		case "j":
			// Set current time on first edit if empty
			if t.isEmpty {
				t.setCurrentTime()
			}
			if t.currentField == TimeField {
				t.adjustTime(-5)
			} else {
				t.adjustDate(-1)
			}
		case "k":
			// Set current time on first edit if empty
			if t.isEmpty {
				t.setCurrentTime()
			}
			if t.currentField == TimeField {
				t.adjustTime(5)
			} else {
				t.adjustDate(1)
			}

		// Time field adjustments (uppercase - 30 minutes) or date adjustments (week)
		case "J":
			// Set current time on first edit if empty
			if t.isEmpty {
				t.setCurrentTime()
			}
			if t.currentField == TimeField {
				t.adjustTime(-30)
			} else {
				t.adjustDate(-7)
			}
		case "K":
			// Set current time on first edit if empty
			if t.isEmpty {
				t.setCurrentTime()
			}
			if t.currentField == TimeField {
				t.adjustTime(30)
			} else {
				t.adjustDate(7)
			}

		// Remove timestamp
		case "d":
			t.timestamp = time.Time{}
			t.isEmpty = true
		}
	}

	return t, nil
}

// setCurrentTime sets the timestamp to the current time and marks it as not empty
func (t *TimestampEditor) setCurrentTime() {
	now := time.Now()
	// Snap to nearest 5 minutes
	minute := now.Minute()
	remainder := minute % 5
	if remainder != 0 {
		if remainder < 3 {
			// Round down
			now = now.Add(-time.Duration(remainder) * time.Minute)
		} else {
			// Round up
			now = now.Add(time.Duration(5-remainder) * time.Minute)
		}
	}
	// Zero out seconds and nanoseconds
	t.timestamp = time.Date(
		now.Year(),
		now.Month(),
		now.Day(),
		now.Hour(),
		now.Minute(),
		0, 0,
		now.Location(),
	)
	t.isEmpty = false
}

// adjustTime adjusts the time by the given number of minutes and snaps to nearest 5 minutes
func (t *TimestampEditor) adjustTime(minutes int) {
	// Add the minutes
	t.timestamp = t.timestamp.Add(time.Duration(minutes) * time.Minute)

	// Snap to nearest 5 minutes
	minute := t.timestamp.Minute()
	remainder := minute % 5
	if remainder != 0 {
		if remainder < 3 {
			// Round down
			t.timestamp = t.timestamp.Add(-time.Duration(remainder) * time.Minute)
		} else {
			// Round up
			t.timestamp = t.timestamp.Add(time.Duration(5-remainder) * time.Minute)
		}
	}

	// Zero out seconds and nanoseconds
	t.timestamp = time.Date(
		t.timestamp.Year(),
		t.timestamp.Month(),
		t.timestamp.Day(),
		t.timestamp.Hour(),
		t.timestamp.Minute(),
		0, 0,
		t.timestamp.Location(),
	)
}

// adjustDate adjusts the date by the given number of days
func (t *TimestampEditor) adjustDate(days int) {
	t.timestamp = t.timestamp.AddDate(0, 0, days)
}

// View renders the timestamp editor
func (t *TimestampEditor) View() string {
	var sb strings.Builder

	styles := t.getStyles()

	// Render title if present
	if t.title != "" {
		sb.WriteString(styles.title.Render(t.title))
		if t.err != nil {
			sb.WriteString(styles.errorIndicator.String())
		}
		sb.WriteString("\n")
	}

	// Render description if present
	if t.description != "" {
		sb.WriteString(styles.description.Render(t.description))
		sb.WriteString("\n")
	}

	// Render the time and date fields side by side
	var timeStr, dateStr string
	if t.isEmpty {
		timeStr = "--:--"
		dateStr = "--- ----------"
	} else {
		timeStr = t.timestamp.Format("15:04")
		dateStr = t.timestamp.Format("Mon 2006-01-02")
	}

	var timeField, dateField string
	if t.currentField == TimeField {
		timeField = styles.selectedField.Render(timeStr)
		dateField = styles.unselectedField.Render(dateStr)
	} else {
		timeField = styles.unselectedField.Render(timeStr)
		dateField = styles.selectedField.Render(dateStr)
	}

	fieldsRow := lipgloss.JoinHorizontal(lipgloss.Top, timeField, "  ", dateField)
	sb.WriteString(fieldsRow)

	return styles.base.Render(sb.String())
}

// getHelpText returns the help text based on the current field
func (t *TimestampEditor) getHelpText() string {
	if t.currentField == TimeField {
		return "h/l: switch field • j/k: ±5min • J/K: ±30min • d: remove"
	}
	return "h/l: switch field • j/k: ±1day • J/K: ±1week • d: remove"
}

// Styles for the timestamp editor
type timestampEditorStyles struct {
	base            lipgloss.Style
	title           lipgloss.Style
	description     lipgloss.Style
	errorIndicator  lipgloss.Style
	selectedField   lipgloss.Style
	unselectedField lipgloss.Style
	help            lipgloss.Style
}

// getStyles returns the styles for the timestamp editor
func (t *TimestampEditor) getStyles() timestampEditorStyles {
	theme := t.common.Styles.Form
	var styles timestampEditorStyles

	if t.focused {
		styles.base = lipgloss.NewStyle()
		styles.title = theme.Focused.Title
		styles.description = theme.Focused.Description
		styles.errorIndicator = theme.Focused.ErrorIndicator
		styles.selectedField = lipgloss.NewStyle().
			Bold(true).
			Padding(0, 2).
			Border(lipgloss.RoundedBorder()).
			BorderForeground(lipgloss.Color("12"))
		styles.unselectedField = lipgloss.NewStyle().
			Padding(0, 2).
			Border(lipgloss.RoundedBorder()).
			BorderForeground(lipgloss.Color("8"))
		styles.help = lipgloss.NewStyle().
			Foreground(lipgloss.Color("8")).
			Italic(true)
	} else {
		styles.base = lipgloss.NewStyle()
		styles.title = theme.Blurred.Title
		styles.description = theme.Blurred.Description
		styles.errorIndicator = theme.Blurred.ErrorIndicator
		styles.selectedField = lipgloss.NewStyle().
			Padding(0, 2).
			Border(lipgloss.RoundedBorder()).
			BorderForeground(lipgloss.Color("8"))
		styles.unselectedField = lipgloss.NewStyle().
			Padding(0, 2).
			Border(lipgloss.HiddenBorder())
		styles.help = lipgloss.NewStyle().
			Foreground(lipgloss.Color("8"))
	}

	return styles
}

// Skip returns whether the timestamp editor should be skipped
func (t *TimestampEditor) Skip() bool {
	return false
}

// Zoom returns whether the timestamp editor should be zoomed
func (t *TimestampEditor) Zoom() bool {
	return false
}

// KeyBinds returns the key bindings for the timestamp editor
func (t *TimestampEditor) KeyBinds() []key.Binding {
	return []key.Binding{
		t.common.Keymap.Left,
		t.common.Keymap.Right,
		t.common.Keymap.Up,
		t.common.Keymap.Down,
	}
}