package chat

import (
	"encoding/base64"
	"fmt"
	"log/slog"
	"net/url"
	"os"
	"path/filepath"
	"strconv"
	"strings"

	"github.com/charmbracelet/bubbles/v2/spinner"
	tea "github.com/charmbracelet/bubbletea/v2"
	"github.com/charmbracelet/lipgloss/v2"
	"github.com/google/uuid"
	"github.com/sst/opencode-sdk-go"
	"github.com/sst/opencode/internal/app"
	"github.com/sst/opencode/internal/clipboard"
	"github.com/sst/opencode/internal/commands"
	"github.com/sst/opencode/internal/components/dialog"
	"github.com/sst/opencode/internal/components/textarea"
	"github.com/sst/opencode/internal/styles"
	"github.com/sst/opencode/internal/theme"
	"github.com/sst/opencode/internal/util"
)

type EditorComponent interface {
	tea.Model
	tea.ViewModel
	Content() string
	Lines() int
	Value() string
	Length() int
	Focused() bool
	Focus() (tea.Model, tea.Cmd)
	Blur()
	Submit() (tea.Model, tea.Cmd)
	Clear() (tea.Model, tea.Cmd)
	Paste() (tea.Model, tea.Cmd)
	Newline() (tea.Model, tea.Cmd)
	SetValue(value string)
	SetValueWithAttachments(value string)
	SetInterruptKeyInDebounce(inDebounce bool)
	SetExitKeyInDebounce(inDebounce bool)
}

type editorComponent struct {
	app                    *app.App
	width                  int
	textarea               textarea.Model
	spinner                spinner.Model
	interruptKeyInDebounce bool
	exitKeyInDebounce      bool
}

func (m *editorComponent) Init() tea.Cmd {
	return tea.Batch(m.textarea.Focus(), m.spinner.Tick, tea.EnableReportFocus)
}

func (m *editorComponent) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
	var cmds []tea.Cmd
	var cmd tea.Cmd

	switch msg := msg.(type) {
	case tea.WindowSizeMsg:
		m.width = msg.Width - 4
		return m, nil
	case spinner.TickMsg:
		m.spinner, cmd = m.spinner.Update(msg)
		return m, cmd
	case tea.KeyPressMsg:
		// Maximize editor responsiveness for printable characters
		if msg.Text != "" {
			m.textarea, cmd = m.textarea.Update(msg)
			cmds = append(cmds, cmd)
			return m, tea.Batch(cmds...)
		}
	case tea.PasteMsg:
		text := string(msg)
		text = strings.ReplaceAll(text, "\\", "")
		text, err := strconv.Unquote(`"` + text + `"`)
		if err != nil {
			slog.Error("Failed to unquote text", "error", err)
			m.textarea.InsertRunesFromUserInput([]rune(msg))
			return m, nil
		}
		if _, err := os.Stat(text); err != nil {
			slog.Error("Failed to paste file", "error", err)
			m.textarea.InsertRunesFromUserInput([]rune(msg))
			return m, nil
		}

		filePath := text

		attachment := m.createAttachmentFromFile(filePath)
		if attachment == nil {
			m.textarea.InsertRunesFromUserInput([]rune(msg))
			return m, nil
		}

		m.textarea.InsertAttachment(attachment)
		m.textarea.InsertString(" ")
	case tea.ClipboardMsg:
		text := string(msg)
		m.textarea.InsertRunesFromUserInput([]rune(text))
	case dialog.ThemeSelectedMsg:
		m.textarea = updateTextareaStyles(m.textarea)
		m.spinner = createSpinner()
		return m, tea.Batch(m.spinner.Tick, m.textarea.Focus())
	case dialog.CompletionSelectedMsg:
		switch msg.Item.ProviderID {
		case "commands":
			commandName := strings.TrimPrefix(msg.Item.Value, "/")
			updated, cmd := m.Clear()
			m = updated.(*editorComponent)
			cmds = append(cmds, cmd)
			cmds = append(cmds, util.CmdHandler(commands.ExecuteCommandMsg(m.app.Commands[commands.CommandName(commandName)])))
			return m, tea.Batch(cmds...)
		case "files":
			atIndex := m.textarea.LastRuneIndex('@')
			if atIndex == -1 {
				// Should not happen, but as a fallback, just insert.
				m.textarea.InsertString(msg.Item.Value + " ")
				return m, nil
			}

			// The range to replace is from the '@' up to the current cursor position.
			// Replace the search term (e.g., "@search") with an empty string first.
			cursorCol := m.textarea.CursorColumn()
			m.textarea.ReplaceRange(atIndex, cursorCol, "")

			// Now, insert the attachment at the position where the '@' was.
			// The cursor is now at `atIndex` after the replacement.
			filePath := msg.Item.Value
			attachment := m.createAttachmentFromPath(filePath)
			m.textarea.InsertAttachment(attachment)
			m.textarea.InsertString(" ")
			return m, nil
		case "symbols":
			atIndex := m.textarea.LastRuneIndex('@')
			if atIndex == -1 {
				// Should not happen, but as a fallback, just insert.
				m.textarea.InsertString(msg.Item.Value + " ")
				return m, nil
			}

			cursorCol := m.textarea.CursorColumn()
			m.textarea.ReplaceRange(atIndex, cursorCol, "")

			symbol := msg.Item.RawData.(opencode.Symbol)
			parts := strings.Split(symbol.Name, ".")
			lastPart := parts[len(parts)-1]
			attachment := &textarea.Attachment{
				ID:        uuid.NewString(),
				Display:   "@" + lastPart,
				URL:       msg.Item.Value,
				Filename:  lastPart,
				MediaType: "text/plain",
			}
			m.textarea.InsertAttachment(attachment)
			m.textarea.InsertString(" ")
			return m, nil
		default:
			slog.Debug("Unknown provider", "provider", msg.Item.ProviderID)
			return m, nil
		}
	}

	m.spinner, cmd = m.spinner.Update(msg)
	cmds = append(cmds, cmd)

	m.textarea, cmd = m.textarea.Update(msg)
	cmds = append(cmds, cmd)

	return m, tea.Batch(cmds...)
}

func (m *editorComponent) Content() string {
	width := m.width
	if m.app.Session.ID == "" {
		width = min(width, 80)
	}

	t := theme.CurrentTheme()
	base := styles.NewStyle().Foreground(t.Text()).Background(t.Background()).Render
	muted := styles.NewStyle().Foreground(t.TextMuted()).Background(t.Background()).Render
	promptStyle := styles.NewStyle().Foreground(t.Primary()).
		Padding(0, 0, 0, 1).
		Bold(true)
	prompt := promptStyle.Render(">")

	m.textarea.SetWidth(width - 6)
	textarea := lipgloss.JoinHorizontal(
		lipgloss.Top,
		prompt,
		m.textarea.View(),
	)
	borderForeground := t.Border()
	if m.app.IsLeaderSequence {
		borderForeground = t.Accent()
	}
	textarea = styles.NewStyle().
		Background(t.BackgroundElement()).
		Width(width).
		PaddingTop(1).
		PaddingBottom(1).
		BorderStyle(lipgloss.ThickBorder()).
		BorderForeground(borderForeground).
		BorderBackground(t.Background()).
		BorderLeft(true).
		BorderRight(true).
		Render(textarea)

	hint := base(m.getSubmitKeyText()) + muted(" send   ")
	if m.exitKeyInDebounce {
		keyText := m.getExitKeyText()
		hint = base(keyText+" again") + muted(" to exit")
	} else if m.app.IsBusy() {
		keyText := m.getInterruptKeyText()
		if m.interruptKeyInDebounce {
			hint = muted(
				"working",
			) + m.spinner.View() + muted(
				"  ",
			) + base(
				keyText+" again",
			) + muted(
				" interrupt",
			)
		} else {
			hint = muted("working") + m.spinner.View() + muted("  ") + base(keyText) + muted(" interrupt")
		}
	}

	model := ""
	if m.app.Model != nil {
		model = muted(m.app.Provider.Name) + base(" "+m.app.Model.Name)
	}

	space := width - 2 - lipgloss.Width(model) - lipgloss.Width(hint)
	spacer := styles.NewStyle().Background(t.Background()).Width(space).Render("")

	info := hint + spacer + model
	info = styles.NewStyle().Background(t.Background()).Padding(0, 1).Render(info)

	content := strings.Join([]string{"", textarea, info}, "\n")
	return content
}

func (m *editorComponent) View() string {
	width := m.width
	if m.app.Session.ID == "" {
		width = min(width, 80)
	}

	if m.Lines() > 1 {
		return lipgloss.Place(
			width,
			5,
			lipgloss.Center,
			lipgloss.Center,
			"",
			styles.WhitespaceStyle(theme.CurrentTheme().Background()),
		)
	}
	return m.Content()
}

func (m *editorComponent) Focused() bool {
	return m.textarea.Focused()
}

func (m *editorComponent) Focus() (tea.Model, tea.Cmd) {
	return m, m.textarea.Focus()
}

func (m *editorComponent) Blur() {
	m.textarea.Blur()
}

func (m *editorComponent) Lines() int {
	return m.textarea.LineCount()
}

func (m *editorComponent) Value() string {
	return m.textarea.Value()
}

func (m *editorComponent) Length() int {
	return m.textarea.Length()
}

func (m *editorComponent) Submit() (tea.Model, tea.Cmd) {
	value := strings.TrimSpace(m.Value())
	if value == "" {
		return m, nil
	}

	switch value {
	case "exit", "quit", "q", ":q":
		return m, tea.Quit
	}

	if len(value) > 0 && value[len(value)-1] == '\\' {
		// If the last character is a backslash, remove it and add a newline
		backslashCol := m.textarea.CurrentRowLength() - 1
		m.textarea.ReplaceRange(backslashCol, backslashCol+1, "")
		m.textarea.InsertString("\n")
		return m, nil
	}

	var cmds []tea.Cmd

	attachments := m.textarea.GetAttachments()
	fileParts := make([]opencode.FilePartInputParam, 0)
	for _, attachment := range attachments {
		fileParts = append(fileParts, opencode.FilePartInputParam{
			Type:     opencode.F(opencode.FilePartInputTypeFile),
			Mime:     opencode.F(attachment.MediaType),
			URL:      opencode.F(attachment.URL),
			Filename: opencode.F(attachment.Filename),
		})
	}

	updated, cmd := m.Clear()
	m = updated.(*editorComponent)
	cmds = append(cmds, cmd)

	cmds = append(cmds, util.CmdHandler(app.SendMsg{Text: value, Attachments: fileParts}))
	return m, tea.Batch(cmds...)
}

func (m *editorComponent) Clear() (tea.Model, tea.Cmd) {
	m.textarea.Reset()
	return m, nil
}

func (m *editorComponent) Paste() (tea.Model, tea.Cmd) {
	imageBytes := clipboard.Read(clipboard.FmtImage)
	if imageBytes != nil {
		attachmentCount := len(m.textarea.GetAttachments())
		attachmentIndex := attachmentCount + 1
		base64EncodedFile := base64.StdEncoding.EncodeToString(imageBytes)
		attachment := &textarea.Attachment{
			ID:        uuid.NewString(),
			MediaType: "image/png",
			Display:   fmt.Sprintf("[Image #%d]", attachmentIndex),
			Filename:  fmt.Sprintf("image-%d.png", attachmentIndex),
			URL:       fmt.Sprintf("data:image/png;base64,%s", base64EncodedFile),
		}
		m.textarea.InsertAttachment(attachment)
		m.textarea.InsertString(" ")
		return m, nil
	}

	textBytes := clipboard.Read(clipboard.FmtText)
	if textBytes != nil {
		m.textarea.InsertRunesFromUserInput([]rune(string(textBytes)))
		return m, nil
	}

	// fallback to reading the clipboard using OSC52
	return m, tea.ReadClipboard
}

func (m *editorComponent) Newline() (tea.Model, tea.Cmd) {
	m.textarea.Newline()
	return m, nil
}

func (m *editorComponent) SetInterruptKeyInDebounce(inDebounce bool) {
	m.interruptKeyInDebounce = inDebounce
}

func (m *editorComponent) SetValue(value string) {
	m.textarea.SetValue(value)
}

func (m *editorComponent) SetValueWithAttachments(value string) {
	m.textarea.Reset()

	i := 0
	for i < len(value) {
		// Check if filepath and add attachment
		if value[i] == '@' {
			start := i + 1
			end := start
			for end < len(value) && value[end] != ' ' && value[end] != '\t' && value[end] != '\n' && value[end] != '\r' {
				end++
			}

			if end > start {
				filePath := value[start:end]
				if _, err := os.Stat(filePath); err == nil {
					attachment := m.createAttachmentFromFile(filePath)
					if attachment != nil {
						m.textarea.InsertAttachment(attachment)
						i = end
						continue
					}
				}
			}
		}

		// Not a valid file path, insert the character normally
		m.textarea.InsertRune(rune(value[i]))
		i++
	}
}

func (m *editorComponent) SetExitKeyInDebounce(inDebounce bool) {
	m.exitKeyInDebounce = inDebounce
}

func (m *editorComponent) getInterruptKeyText() string {
	return m.app.Commands[commands.SessionInterruptCommand].Keys()[0]
}

func (m *editorComponent) getSubmitKeyText() string {
	return m.app.Commands[commands.InputSubmitCommand].Keys()[0]
}

func (m *editorComponent) getExitKeyText() string {
	return m.app.Commands[commands.AppExitCommand].Keys()[0]
}

func updateTextareaStyles(ta textarea.Model) textarea.Model {
	t := theme.CurrentTheme()
	bgColor := t.BackgroundElement()
	textColor := t.Text()
	textMutedColor := t.TextMuted()

	ta.Styles.Blurred.Base = styles.NewStyle().Foreground(textColor).Background(bgColor).Lipgloss()
	ta.Styles.Blurred.CursorLine = styles.NewStyle().Background(bgColor).Lipgloss()
	ta.Styles.Blurred.Placeholder = styles.NewStyle().
		Foreground(textMutedColor).
		Background(bgColor).
		Lipgloss()
	ta.Styles.Blurred.Text = styles.NewStyle().Foreground(textColor).Background(bgColor).Lipgloss()
	ta.Styles.Focused.Base = styles.NewStyle().Foreground(textColor).Background(bgColor).Lipgloss()
	ta.Styles.Focused.CursorLine = styles.NewStyle().Background(bgColor).Lipgloss()
	ta.Styles.Focused.Placeholder = styles.NewStyle().
		Foreground(textMutedColor).
		Background(bgColor).
		Lipgloss()
	ta.Styles.Focused.Text = styles.NewStyle().Foreground(textColor).Background(bgColor).Lipgloss()
	ta.Styles.Attachment = styles.NewStyle().
		Foreground(t.Secondary()).
		Background(bgColor).
		Lipgloss()
	ta.Styles.SelectedAttachment = styles.NewStyle().
		Foreground(t.Text()).
		Background(t.Secondary()).
		Lipgloss()
	ta.Styles.Cursor.Color = t.Primary()
	return ta
}

func createSpinner() spinner.Model {
	t := theme.CurrentTheme()
	return spinner.New(
		spinner.WithSpinner(spinner.Ellipsis),
		spinner.WithStyle(
			styles.NewStyle().
				Background(t.Background()).
				Foreground(t.TextMuted()).
				Width(3).
				Lipgloss(),
		),
	)
}

func NewEditorComponent(app *app.App) EditorComponent {
	s := createSpinner()

	ta := textarea.New()
	ta.Prompt = " "
	ta.ShowLineNumbers = false
	ta.CharLimit = -1
	ta = updateTextareaStyles(ta)

	m := &editorComponent{
		app:                    app,
		textarea:               ta,
		spinner:                s,
		interruptKeyInDebounce: false,
	}

	return m
}

func getMediaTypeFromExtension(ext string) string {
	switch strings.ToLower(ext) {
	case ".jpg":
		return "image/jpeg"
	case ".png", ".jpeg", ".gif", ".webp":
		return "image/" + ext[1:]
	case ".pdf":
		return "application/pdf"
	default:
		return "text/plain"
	}
}

func (m *editorComponent) createAttachmentFromFile(filePath string) *textarea.Attachment {
	ext := strings.ToLower(filepath.Ext(filePath))
	mediaType := getMediaTypeFromExtension(ext)

	// For text files, create a simple file reference
	if mediaType == "text/plain" {
		return &textarea.Attachment{
			ID:        uuid.NewString(),
			Display:   "@" + filePath,
			URL:       fmt.Sprintf("file://./%s", filePath),
			Filename:  filePath,
			MediaType: mediaType,
		}
	}

	// For binary files (images, PDFs), read and encode
	fileBytes, err := os.ReadFile(filePath)
	if err != nil {
		slog.Error("Failed to read file", "error", err)
		return nil
	}

	base64EncodedFile := base64.StdEncoding.EncodeToString(fileBytes)
	url := fmt.Sprintf("data:%s;base64,%s", mediaType, base64EncodedFile)
	attachmentCount := len(m.textarea.GetAttachments())
	attachmentIndex := attachmentCount + 1
	label := "File"
	if strings.HasPrefix(mediaType, "image/") {
		label = "Image"
	}

	return &textarea.Attachment{
		ID:        uuid.NewString(),
		MediaType: mediaType,
		Display:   fmt.Sprintf("[%s #%d]", label, attachmentIndex),
		URL:       url,
		Filename:  filePath,
	}
}

func (m *editorComponent) createAttachmentFromPath(filePath string) *textarea.Attachment {
	extension := filepath.Ext(filePath)
	mediaType := getMediaTypeFromExtension(extension)

	return &textarea.Attachment{
		ID:        uuid.NewString(),
		Display:   "@" + filePath,
		URL:       fmt.Sprintf("file://./%s", url.PathEscape(filePath)),
		Filename:  filePath,
		MediaType: mediaType,
	}
}
