package ui

import (
	"fmt"
	"os"
	"path"
	"strings"

	"github.com/charmbracelet/bubbles/viewport"
	tea "github.com/charmbracelet/bubbletea"
)

const (
	// Status is the status buffer.
	Status = iota
	// Profile is the profile buffer.
	Profile
)

// BufferHandler is the concrete functionality of a Buffer.
type BufferHandler interface {
	validate(m model, input string) error     // validate incoming input
	handle(input, hiddenInput string) tea.Msg // handle and dispatch messages from input
	persist(m *model, input string)           // store buffer input for persistence
	close(m model) error                      // gracefully destroy a buffer
}

// Buffer is a user-facing interactive buffer in the TUI.
type Buffer struct {
	name            string         // user-friendly buffer name for the menu
	inputChannel    chan string    // channel for passing input to handlers
	viewport        viewport.Model // viewport for rendering lines
	viewportLines   []string       // lines for viewport renderer
	viewportIsReady bool           // whether or not the viewport is ready to render
	inputHistory    []string       // buffer input history for optional persistence
	persistence     bool           // whether or not to persist buffer input to file

	BufferHandler
}

// StatusBuffer is the privileged status buffer where e.g. you input
// program-wide commands. It can also report general status information, e.g.
// the status of ACN connectivity.
type StatusBufferHandler Buffer

func (s StatusBufferHandler) validate(m model, input string) error {
	if string(input[0]) != "/" {
		return fmt.Errorf("Woops, this is not a chat buffer. Only commands are allowed")
	}
	return nil
}

func (s StatusBufferHandler) handle(input, hiddenInput string) tea.Msg {
	cmds := strings.Split(input, " ")

	switch {
	case cmds[0] == "help":
		return cmdMsg{output: strings.Split(cmdHelp, "\n")}

	case cmds[0] == "quit":
		return turnAcnOffMsg{quitProgram: true}

	case cmds[0] == "start":
		return showGettingStartedGuideMsg{}

	case cmds[0] == "profile":
		if cmds[1] != "unlock" && cmds[1] != "info" && cmds[1] != "create" {
			profileHelp := `Unknown "profile" command?
/profile create <name> <password> <password> | Create a new profile
/profile info                                | Show profile information
/profile unlock <password>                   | Unlock profile(s)`
			return cmdMsg{output: strings.Split(profileHelp, "\n")}
		}

		switch {
		case cmds[1] == "unlock":
			if len(cmds) != 3 {
				return cmdMsg{output: strings.Split(cmdHelp, "\n")}
			}

			return profileUnlockMsg{
				password: strings.TrimSpace(hiddenInput),
			}

		case cmds[1] == "info":
			return profileInfoMsg{}

		case cmds[1] == "create":
			if len(cmds) != 5 {
				return cmdMsg{output: strings.Split(cmdHelp, "\n")}
			}

			passwords := strings.Split(strings.TrimSpace(hiddenInput), " ")
			if len(passwords) != 2 {
				return cmdMsg{output: []string{"Profile create: unable to parse hidden input"}}
			}

			if passwords[0] != passwords[1] {
				return cmdMsg{output: []string{"Profile create: passwords do not match?"}}
			}

			return profileCreateMsg{
				name:     cmds[2],
				password: passwords[1],
			}
		}

	case cmds[0] == "acn":
		if cmds[1] != "on" && cmds[1] != "off" {
			acnHelp := `Unknown "acn" command?
/acn on  | Turn on the Tor ACN
/acn off | Turn off the Tor ACN`
			return cmdMsg{output: strings.Split(acnHelp, "\n")}
		}

		switch {
		case cmds[1] == "on":
			return turnAcnOnMsg{}
		case cmds[1] == "off":
			return turnAcnOffMsg{}
		}

	case cmds[0] == "clear":
		return clearScreenMsg{}
	}

	return cmdMsg{output: []string{unknownCmdHelp}}
}

func (s StatusBufferHandler) persist(m *model, input string) {
	buffer := m.buffers[m.menuState]
	if buffer.persistence {
		buffer.inputHistory = append(buffer.inputHistory, input)
		m.buffers[m.menuState] = buffer
	}
}

func (s StatusBufferHandler) close(m model) error {
	buffer := m.buffers[m.menuState]
	cairdeLogsDir := path.Join(m.userDir, "logs")
	bufferLogsPath := path.Join(cairdeLogsDir, buffer.name)

	if !buffer.persistence {
		return nil
	}

	f, err := os.OpenFile(bufferLogsPath, os.O_RDWR|os.O_CREATE|os.O_APPEND, 0664)
	if err != nil {
		return fmt.Errorf("unable to create/open file %s: %s", bufferLogsPath, err)
	}

	for _, cmd := range buffer.inputHistory {
		if _, err := f.WriteString(cmd + "\n"); err != nil {
			return fmt.Errorf("unable to append input to %s: %s", bufferLogsPath, err)
		}
	}

	if err := f.Close(); err != nil {
		return fmt.Errorf("unable to close %s file handler: %s", bufferLogsPath, err)
	}

	return nil
}

// ProfileBuffer is the profile buffer. There can be several profile buffers
// which correspond to several profiles. Profile buffers take input and report
// output for profile-specific information, e.g. invites from a new contact.
type ProfileBuffer Buffer