package table

import (
	"strings"

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

// Model defines a state for the table widget.
type Model struct {
	KeyMap KeyMap
	Help   help.Model

	yoffset int
	height  int
	headers []string
	rows    [][]string
	cursor  int
	focus   bool
	styles  Styles

	table *table.Table
	start int
	end   int

	// deprecated: don't use viewport, use table instead.
	viewport viewport.Model
}

// Row represents one line in the table.
// Deprecated: use []string.
type Row []string

// Column defines the table structure.
// Deprecated: use []string.
type Column struct {
	Title string
	Width int
}

// KeyMap defines keybindings. It satisfies to the help.KeyMap interface, which
// is used to render the help menu.
type KeyMap struct {
	LineUp       key.Binding
	LineDown     key.Binding
	PageUp       key.Binding
	PageDown     key.Binding
	HalfPageUp   key.Binding
	HalfPageDown key.Binding
	GotoTop      key.Binding
	GotoBottom   key.Binding
}

// ShortHelp implements the KeyMap interface.
func (km KeyMap) ShortHelp() []key.Binding {
	return []key.Binding{km.LineUp, km.LineDown}
}

// FullHelp implements the KeyMap interface.
func (km KeyMap) FullHelp() [][]key.Binding {
	return [][]key.Binding{
		{km.LineUp, km.LineDown, km.GotoTop, km.GotoBottom},
		{km.PageUp, km.PageDown, km.HalfPageUp, km.HalfPageDown},
	}
}

// DefaultKeyMap returns a default set of keybindings.
func DefaultKeyMap() KeyMap {
	const spacebar = " "
	return KeyMap{
		LineUp: key.NewBinding(
			key.WithKeys("up", "k"),
			key.WithHelp("↑/k", "up"),
		),
		LineDown: key.NewBinding(
			key.WithKeys("down", "j"),
			key.WithHelp("↓/j", "down"),
		),
		PageUp: key.NewBinding(
			key.WithKeys("b", "pgup"),
			key.WithHelp("b/pgup", "page up"),
		),
		PageDown: key.NewBinding(
			key.WithKeys("f", "pgdown", spacebar),
			key.WithHelp("f/pgdn", "page down"),
		),
		HalfPageUp: key.NewBinding(
			key.WithKeys("u", "ctrl+u"),
			key.WithHelp("u", "½ page up"),
		),
		HalfPageDown: key.NewBinding(
			key.WithKeys("d", "ctrl+d"),
			key.WithHelp("d", "½ page down"),
		),
		GotoTop: key.NewBinding(
			key.WithKeys("home", "g"),
			key.WithHelp("g/home", "go to start"),
		),
		GotoBottom: key.NewBinding(
			key.WithKeys("end", "G"),
			key.WithHelp("G/end", "go to end"),
		),
	}
}

// Styles contains style definitions for this list component. By default, these
// values are generated by DefaultStyles.
type Styles struct {
	Border       lipgloss.Border
	BorderStyle  lipgloss.Style
	BorderHeader bool
	Header       lipgloss.Style
	Cell         lipgloss.Style
	Selected     lipgloss.Style
}

// DefaultStyles returns a set of default style definitions for this table.
func DefaultStyles() Styles {
	return Styles{
		Border:       lipgloss.NormalBorder(),
		BorderHeader: true,
		Selected:     lipgloss.NewStyle().Bold(true).Foreground(lipgloss.Color("212")).Margin(0, 1),
		Header:       lipgloss.NewStyle().Bold(true).Padding(0, 1),
		Cell:         lipgloss.NewStyle().Margin(0, 1),
	}
}

// SetStyles sets the table styles.
func (m *Model) SetStyles(s Styles) {
	m.styles = s
	m.table.Border(s.Border)
	m.table.BorderStyle(s.BorderStyle)
	m.table.BorderHeader(s.BorderHeader)
}

// TODO make this able to be set with same no args as lipgloss.BorderForeground
func (m *Model) SetBorder(top, right, bottom, left bool) {
	m.table.
		BorderTop(top).
		BorderRight(right).
		BorderBottom(bottom).
		BorderLeft(left)
}

// Option is used to set options in New. For example:
//
//	table := New(WithRows([]Row{{"Foo"},{"Bar"},{"Baz"},}))
type Option func(*Model)

// New creates a new model for the table widget.
func New(opts ...Option) Model {
	m := Model{
		table:  table.New(),
		KeyMap: DefaultKeyMap(),
		Help:   help.New(),
		styles: DefaultStyles(),
	}

	for _, opt := range opts {
		opt(&m)
	}

	return m
}

// WithHeaders sets the table headers.
func WithHeaders(headers []string) Option {
	return func(m *Model) {
		m.SetHeaders(headers...)
	}
}

// WithColumns sets the table columns (headers).
// Deprecated: use WithHeaders instead.
func WithColumns(cols []Column) Option {
	return func(m *Model) {
		m.SetHeaders(colToString(cols)...)
	}
}

// colToString helper to unwrap the Column type to its underlying string type.
func colToString(cols []Column) []string {
	var out []string
	for _, col := range cols {
		out = append(out, col.Title)
	}
	return out
}

// WithRows sets the table rows (data).
func WithRows(rows []Row) Option {
	return func(m *Model) {
		m.SetRows(rows)
	}
}

// WithHeight sets the height of the table.
func WithHeight(h int) Option {
	return func(m *Model) {
		m.SetHeight(h)
	}
}

// WithWidth sets the width of the table.
func WithWidth(w int) Option {
	return func(m *Model) {
		m.SetWidth(w)
	}
}

// WithFocused sets the focus state of the table.
func WithFocused(f bool) Option {
	return func(m *Model) {
		m.focus = f
	}
}

// WithStyles sets the table styles.
func WithStyles(s Styles) Option {
	return func(m *Model) {
		m.SetStyles(s)
	}
}

// WithKeyMap sets the key map.
func WithKeyMap(km KeyMap) Option {
	return func(m *Model) {
		m.KeyMap = km
	}
}

// Update for the Bubble Tea update loop.
func (m Model) Update(msg tea.Msg) (Model, tea.Cmd) {
	if !m.focus {
		return m, nil
	}

	switch msg := msg.(type) {
	case tea.KeyMsg:
		switch {
		case key.Matches(msg, m.KeyMap.LineUp):
			m.MoveUp(1)
		case key.Matches(msg, m.KeyMap.LineDown):
			m.MoveDown(1)
		case key.Matches(msg, m.KeyMap.PageUp):
			m.MoveUp(m.height)
		case key.Matches(msg, m.KeyMap.PageDown):
			m.MoveDown(m.height)
		case key.Matches(msg, m.KeyMap.HalfPageUp):
			m.MoveUp(m.height / 2)
		case key.Matches(msg, m.KeyMap.HalfPageDown):
			m.MoveDown(m.height / 2)
		case key.Matches(msg, m.KeyMap.LineDown):
			m.MoveDown(1)
		case key.Matches(msg, m.KeyMap.GotoTop):
			m.GotoTop()
		case key.Matches(msg, m.KeyMap.GotoBottom):
			m.GotoBottom()
		}
	}

	return m, nil
}

// Focused returns the focus state of the table.
func (m Model) Focused() bool {
	return m.focus
}

// Focus focuses the table, allowing the user to move around the rows and
// interact.
func (m *Model) Focus() {
	m.focus = true
}

// Blur blurs the table, preventing selection or movement.
func (m *Model) Blur() {
	m.focus = false
}

// View renders the component.
func (m Model) View() string {
	m.table.StyleFunc(func(row, col int) lipgloss.Style {
		if row == table.HeaderRow {
			return m.styles.Header
		}
		if row == m.cursor {
			return m.styles.Selected
		}
		return m.styles.Cell
	})

	return m.table.String()
}

// HelpView is a helper method for rendering the help menu from the keymap.
// Note that this view is not rendered by default and you must call it
// manually in your application, where applicable.
func (m Model) HelpView() string {
	return m.Help.View(m.KeyMap)
}

// SelectedRow returns the selected row.
// You can cast it to your own implementation.
func (m Model) SelectedRow() Row {
	if m.cursor < 0 || m.cursor >= len(m.rows) {
		return nil
	}

	return m.rows[m.cursor]
}

// Append appends rows to the table.
func (m *Model) Append(rows ...[]string) {
	m.rows = append(m.rows, rows...)
	m.table.Rows(m.rows...)
}

// SetRows overwrites existing rows with new ones.
func (m *Model) SetRows(r []Row) {
	// lipgloss' table requires []string, so it's easier to convert these.
	// TODO should we just deprecate the Row type altogether?
	rows := rowToString(r)
	m.rows = rows
	m.table.ClearRows()
	m.table.Rows(rows...)
}

// rowToString helper to unwrap the Row type.
func rowToString(rows []Row) [][]string {
	var out [][]string
	for _, row := range rows {
		var newRow []string
		for _, val := range row {
			newRow = append(newRow, val)
		}
		out = append(out, newRow)
	}
	return out
}

// SetHeaders sets the table headers.
// TODO should this be variadic to match lipgloss table?
func (m *Model) SetHeaders(headers ...string) {
	m.headers = headers
	m.table.Headers(headers...)
}

// SetWidth sets the width of the table.
func (m *Model) SetWidth(w int) {
	m.table.Width(w)
}

// SetHeight sets the height of the table.
func (m *Model) SetHeight(h int) {
	m.height = h
	m.table.Height(h)
}

// Cursor returns the index of the selected row.
func (m Model) Cursor() int {
	return m.cursor
}

// SetCursor sets the cursor position in the table.
func (m *Model) SetCursor(n int) {
	m.cursor = clamp(n, 0, len(m.rows)-1)
}

// setYOffset sets the YOffset position in the table.
func (m *Model) setYOffset(n int) {
	m.yoffset = clamp(n, 0, len(m.rows)-1)
}

// MoveUp moves the selection up by any number of rows.
// It can not go above the first row.
func (m *Model) MoveUp(n int) {
	m.SetCursor(m.cursor - n)

	// only set the offset outside of the last available rows.
	m.setYOffset(m.yoffset - n)
	m.table.Offset(m.yoffset)
}

// MoveDown moves the selection down by any number of rows.
// It can not go below the last row.
func (m *Model) MoveDown(n int) {
	// once we're at the last set of rows, where there is no truncation
	// stop setting the y offset and only move cursor

	// visible lines after updating viewport
	m.SetCursor(m.cursor + n)

	m.setYOffset(m.yoffset + n)
	m.table.Offset(m.yoffset)
}

// GotoTop moves the selection to the first row.
func (m *Model) GotoTop() {
	m.MoveUp(m.cursor)
}

// GotoBottom moves the selection to the last row.
func (m *Model) GotoBottom() {
	m.MoveDown(len(m.rows))
}

// FromValues create the table rows from a simple string. It uses `\n` by
// default for getting all the rows and the given separator for the fields on
// each row.
func (m *Model) FromValues(value, separator string) {
	rows := []Row{}
	for _, line := range strings.Split(value, "\n") {
		r := Row{}
		for _, field := range strings.Split(line, separator) {
			r = append(r, field)
		}
		rows = append(rows, r)
	}

	m.SetRows(rows)
}

func max(a, b int) int {
	if a > b {
		return a
	}

	return b
}

func min(a, b int) int {
	if a < b {
		return a
	}

	return b
}

func clamp(v, low, high int) int {
	return min(max(v, low), high)
}