package chat

import (
	"os"
	"os/exec"

	"github.com/charmbracelet/bubbles/key"
	"github.com/charmbracelet/bubbles/textarea"
	tea "github.com/charmbracelet/bubbletea"
	"github.com/charmbracelet/lipgloss"
	"github.com/opencode-ai/opencode/internal/app"
	"github.com/opencode-ai/opencode/internal/session"
	"github.com/opencode-ai/opencode/internal/tui/components/dialog"
	"github.com/opencode-ai/opencode/internal/tui/layout"
	"github.com/opencode-ai/opencode/internal/tui/styles"
	"github.com/opencode-ai/opencode/internal/tui/theme"
	"github.com/opencode-ai/opencode/internal/tui/util"
)

type editorCmp struct {
	app      *app.App
	session  session.Session
	textarea textarea.Model
}

type EditorKeyMaps struct {
	Send       key.Binding
	OpenEditor key.Binding
}

type bluredEditorKeyMaps struct {
	Send       key.Binding
	Focus      key.Binding
	OpenEditor key.Binding
}

var editorMaps = EditorKeyMaps{
	Send: key.NewBinding(
		key.WithKeys("enter", "ctrl+s"),
		key.WithHelp("enter", "send message"),
	),
	OpenEditor: key.NewBinding(
		key.WithKeys("ctrl+e"),
		key.WithHelp("ctrl+e", "open editor"),
	),
}

func openEditor(value string) tea.Cmd {
	editor := os.Getenv("EDITOR")
	if editor == "" {
		editor = "nvim"
	}

	tmpfile, err := os.CreateTemp("", "msg_*.md")
	tmpfile.WriteString(value)
	if err != nil {
		return util.ReportError(err)
	}
	tmpfile.Close()
	c := exec.Command(editor, tmpfile.Name()) //nolint:gosec
	c.Stdin = os.Stdin
	c.Stdout = os.Stdout
	c.Stderr = os.Stderr
	return tea.ExecProcess(c, func(err error) tea.Msg {
		if err != nil {
			return util.ReportError(err)
		}
		content, err := os.ReadFile(tmpfile.Name())
		if err != nil {
			return util.ReportError(err)
		}
		if len(content) == 0 {
			return util.ReportWarn("Message is empty")
		}
		os.Remove(tmpfile.Name())
		return SendMsg{
			Text: string(content),
		}
	})
}

func (m *editorCmp) Init() tea.Cmd {
	return textarea.Blink
}

func (m *editorCmp) send() tea.Cmd {
	if m.app.CoderAgent.IsSessionBusy(m.session.ID) {
		return util.ReportWarn("Agent is working, please wait...")
	}

	value := m.textarea.Value()
	m.textarea.Reset()
	if value == "" {
		return nil
	}
	return tea.Batch(
		util.CmdHandler(SendMsg{
			Text: value,
		}),
	)
}

func (m *editorCmp) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
	var cmd tea.Cmd
	switch msg := msg.(type) {
	case dialog.ThemeChangedMsg:
		m.textarea = CreateTextArea(&m.textarea)
		return m, nil
	case SessionSelectedMsg:
		if msg.ID != m.session.ID {
			m.session = msg
		}
		return m, nil
	case tea.KeyMsg:
		if key.Matches(msg, messageKeys.PageUp) || key.Matches(msg, messageKeys.PageDown) ||
			key.Matches(msg, messageKeys.HalfPageUp) || key.Matches(msg, messageKeys.HalfPageDown) {
			return m, nil
		}
		if key.Matches(msg, editorMaps.OpenEditor) {
			if m.app.CoderAgent.IsSessionBusy(m.session.ID) {
				return m, util.ReportWarn("Agent is working, please wait...")
			}
			value := m.textarea.Value()
			m.textarea.Reset()
			return m, openEditor(value)
		}
		// Handle Enter key
		if m.textarea.Focused() && key.Matches(msg, editorMaps.Send) {
			value := m.textarea.Value()
			if len(value) > 0 && value[len(value)-1] == '\\' {
				// If the last character is a backslash, remove it and add a newline
				m.textarea.SetValue(value[:len(value)-1] + "\n")
				return m, nil
			} else {
				// Otherwise, send the message
				return m, m.send()
			}
		}
	}
	m.textarea, cmd = m.textarea.Update(msg)
	return m, cmd
}

func (m *editorCmp) View() string {
	t := theme.CurrentTheme()

	// Style the prompt with theme colors
	style := lipgloss.NewStyle().
		Padding(0, 0, 0, 1).
		Bold(true).
		Foreground(t.Primary())

	return lipgloss.JoinHorizontal(lipgloss.Top, style.Render(">"), m.textarea.View())
}

func (m *editorCmp) SetSize(width, height int) tea.Cmd {
	m.textarea.SetWidth(width - 3) // account for the prompt and padding right
	m.textarea.SetHeight(height)
	return nil
}

func (m *editorCmp) GetSize() (int, int) {
	return m.textarea.Width(), m.textarea.Height()
}

func (m *editorCmp) BindingKeys() []key.Binding {
	bindings := []key.Binding{}
	bindings = append(bindings, layout.KeyMapToSlice(editorMaps)...)
	return bindings
}

func CreateTextArea(existing *textarea.Model) textarea.Model {
	t := theme.CurrentTheme()
	bgColor := t.Background()
	textColor := t.Text()
	textMutedColor := t.TextMuted()

	ta := textarea.New()
	ta.BlurredStyle.Base = styles.BaseStyle().Background(bgColor).Foreground(textColor)
	ta.BlurredStyle.CursorLine = styles.BaseStyle().Background(bgColor)
	ta.BlurredStyle.Placeholder = styles.BaseStyle().Background(bgColor).Foreground(textMutedColor)
	ta.BlurredStyle.Text = styles.BaseStyle().Background(bgColor).Foreground(textColor)
	ta.FocusedStyle.Base = styles.BaseStyle().Background(bgColor).Foreground(textColor)
	ta.FocusedStyle.CursorLine = styles.BaseStyle().Background(bgColor)
	ta.FocusedStyle.Placeholder = styles.BaseStyle().Background(bgColor).Foreground(textMutedColor)
	ta.FocusedStyle.Text = styles.BaseStyle().Background(bgColor).Foreground(textColor)

	ta.Prompt = " "
	ta.ShowLineNumbers = false
	ta.CharLimit = -1

	if existing != nil {
		ta.SetValue(existing.Value())
		ta.SetWidth(existing.Width())
		ta.SetHeight(existing.Height())
	}

	ta.Focus()
	return ta
}

func NewEditorCmp(app *app.App) tea.Model {
	ta := CreateTextArea(nil)

	return &editorCmp{
		app:      app,
		textarea: ta,
	}
}
