package chat

import (
	"fmt"
	"strings"

	"git.mlow.ca/mlow/lmcli/pkg/api"
	"git.mlow.ca/mlow/lmcli/pkg/conversation"
	"git.mlow.ca/mlow/lmcli/pkg/tui/model"
	"git.mlow.ca/mlow/lmcli/pkg/tui/shared"
	tuiutil "git.mlow.ca/mlow/lmcli/pkg/tui/util"
	tea "github.com/charmbracelet/bubbletea"
)

func (m *Model) handleInput(msg tea.KeyMsg) tea.Cmd {
	switch m.focus {
	case focusInput:
		cmd := m.handleInputKey(msg)
		if cmd != nil {
			return cmd
		}
	case focusMessages:
		cmd := m.handleMessagesKey(msg)
		if cmd != nil {
			return cmd
		}
	}

	switch msg.String() {
	case "esc":
		if m.state == pendingResponse {
			m.stopSignal <- struct{}{}
			return shared.KeyHandled(msg)
		}
		return func() tea.Msg {
			return shared.MsgViewChange(shared.ViewConversations)
		}
	case "ctrl+c":
		if m.state == pendingResponse {
			m.stopSignal <- struct{}{}
			return shared.KeyHandled(msg)
		}
	case "ctrl+g":
		if m.state == pendingResponse {
			m.stopSignal <- struct{}{}
			return shared.KeyHandled(msg)
		}
		return func() tea.Msg {
			return shared.MsgViewChange(shared.ViewSettings)
		}
	case "ctrl+p":
		m.persistence = !m.persistence
		return shared.KeyHandled(msg)
	case "ctrl+t":
		m.showDetails = !m.showDetails
		m.rebuildMessageCache()
		m.updateContent()
		return shared.KeyHandled(msg)
	case "ctrl+w":
		m.wrap = !m.wrap
		m.rebuildMessageCache()
		m.updateContent()
		return shared.KeyHandled(msg)
	case "ctrl+n":
		m.App.NewConversation()
		m.rebuildMessageCache()
		m.updateContent()
		return shared.KeyHandled(msg)
	}
	return nil
}

func (m *Model) scrollSelection(dir int) {
	if m.selectedMessage+dir < 0 || m.selectedMessage+dir >= len(m.App.Messages) {
		return
	}

	newIdx := m.selectedMessage
	for i := newIdx + dir; i >= 0 && i < len(m.App.Messages); i += dir {
		if !m.showDetails && m.App.Messages[i].Role.IsSystem() {
			continue
		}
		newIdx = i
		break
	}
	if newIdx != m.selectedMessage {
		m.selectedMessage = newIdx
		m.updateContent()
	}
	yOffset := m.messageOffsets[m.selectedMessage]
	tuiutil.ScrollIntoView(&m.content, yOffset, m.content.Height/2)
}

// handleMessagesKey handles input when the messages pane is focused
func (m *Model) handleMessagesKey(msg tea.KeyMsg) tea.Cmd {
	switch msg.String() {
	case "tab", "enter":
		m.focus = focusInput
		m.updateContent()
		m.input.Focus()
		return shared.KeyHandled(msg)
	case "e":
		if m.selectedMessage < len(m.App.Messages) {
			m.editorTarget = selectedMessage
			return tuiutil.OpenTempfileEditor(
				"message.*.md",
				m.App.Messages[m.selectedMessage].Content,
				"# Edit the message below\n",
			)
		}
		return nil
	case "ctrl+k", "ctrl+up":
		if m.selectedMessage > 0 {
			m.scrollSelection(-1)
		}
		return shared.KeyHandled(msg)
	case "ctrl+j", "ctrl+down":
		if m.selectedMessage < len(m.App.Messages)-1 {
			m.scrollSelection(1)
		}
		return shared.KeyHandled(msg)
	case "ctrl+h", "ctrl+left", "ctrl+l", "ctrl+right":
		dir := model.CyclePrev
		if msg.String() == "ctrl+l" || msg.String() == "ctrl+right" {
			dir = model.CycleNext
		}

		var cmd tea.Cmd
		if m.selectedMessage == 0 {
			cmd = m.cycleSelectedRoot(m.App.Conversation, dir)
		} else if m.selectedMessage > 0 {
			cmd = m.cycleSelectedReply(&m.App.Messages[m.selectedMessage-1], dir)
		}
		return cmd
	case "ctrl+r":
		// prompt the model with all messages up to and including the selected message
		if m.state == idle && m.selectedMessage < len(m.App.Messages) {
			m.App.Messages = m.App.Messages[:m.selectedMessage+1]
			m.messageCache = m.messageCache[:m.selectedMessage+1]
			cmd := m.promptLLM()
			m.updateContent()
			m.content.GotoBottom()
			return cmd
		}
	}
	return nil
}

// handleInputKey handles input when the input textarea is focused
func (m *Model) handleInputKey(msg tea.KeyMsg) tea.Cmd {
	switch msg.String() {
	case "esc":
		m.focus = focusMessages
		if len(m.App.Messages) > 0 {
			if m.selectedMessage < 0 || m.selectedMessage >= len(m.App.Messages) {
				m.selectedMessage = len(m.App.Messages) - 1
			}
			offset := m.messageOffsets[m.selectedMessage]
			tuiutil.ScrollIntoView(&m.content, offset, m.content.Height/2)
		}
		m.updateContent()
		m.input.Blur()
		return shared.KeyHandled(msg)
	case "ctrl+s":
		// TODO: call a "handleSend" function which returns a tea.Cmd
		if m.state != idle {
			return nil
		}

		input := strings.TrimSpace(m.input.Value())
		if input == "" {
			return shared.KeyHandled(msg)
		}

		if len(m.App.Messages) > 0 && m.App.Messages[len(m.App.Messages)-1].Role == api.MessageRoleUser {
			return shared.WrapError(fmt.Errorf("Can't reply to a user message"))
		}

		m.addMessage(conversation.Message{
			Role:    api.MessageRoleUser,
			Content: input,
		})

		m.input.SetValue("")

		var cmds []tea.Cmd
		if m.persistence {
			cmds = append(cmds, m.persistConversation())
		}

		cmds = append(cmds, m.promptLLM())

		m.updateContent()
		m.content.GotoBottom()
		return tea.Batch(cmds...)
	case "ctrl+e":
		cmd := tuiutil.OpenTempfileEditor("message.*.md", m.input.Value(), "# Edit your input below\n")
		m.editorTarget = input
		return cmd
	}
	return nil
}