package tui

import (
	"os"
	"os/exec"
	"strings"

	"github.com/charmbracelet/bubbles/viewport"
	tea "github.com/charmbracelet/bubbletea"
	"github.com/muesli/reflow/ansi"
)

type msgTempfileEditorClosed string

// openTempfileEditor opens an $EDITOR on a new temporary file with the given
// content. Upon closing, the contents of the file are read back returned
// wrapped in a msgTempfileEditorClosed returned by the tea.Cmd
func openTempfileEditor(pattern string, content string, placeholder string) tea.Cmd {
	msgFile, _ := os.CreateTemp("/tmp", pattern)

	err := os.WriteFile(msgFile.Name(), []byte(placeholder+content), os.ModeAppend)
	if err != nil {
		return wrapError(err)
	}

	editor := os.Getenv("EDITOR")
	if editor == "" {
		editor = "vim"
	}

	c := exec.Command(editor, msgFile.Name())
	return tea.ExecProcess(c, func(err error) tea.Msg {
		bytes, err := os.ReadFile(msgFile.Name())
		if err != nil {
			return msgError(err)
		}
		os.Remove(msgFile.Name())
		fileContents := string(bytes)
		if strings.HasPrefix(fileContents, placeholder) {
			fileContents = fileContents[len(placeholder):]
		}
		stripped := strings.Trim(fileContents, "\n \t")
		return msgTempfileEditorClosed(stripped)
	})
}

// similar to lipgloss.Height, except returns 0 on empty strings
func height(str string) int {
	if str == "" {
		return 0
	}
	return strings.Count(str, "\n") + 1
}

// truncate a string until its rendered cell width + the provided tail fits
// within the given width
func truncateToCellWidth(str string, width int, tail string) string {
	cellWidth := ansi.PrintableRuneWidth(str)
	if cellWidth <= width {
		return str
	}
	tailWidth := ansi.PrintableRuneWidth(tail)
	for {
		str = str[:len(str)-((cellWidth+tailWidth)-width)]
		cellWidth = ansi.PrintableRuneWidth(str)
		if cellWidth+tailWidth <= max(width, 0) {
			break
		}
	}
	return str + tail
}

// fraction is the fraction of the total screen height into view the offset
// should be scrolled into view. 0.5 = items will be snapped to middle of
// view
func scrollIntoView(vp *viewport.Model, offset int, edge int) {
	currentOffset := vp.YOffset
	if offset >= currentOffset && offset < currentOffset+vp.Height {
		return
	}
	distance := currentOffset - offset
	if distance < 0 {
		// we should scroll down until it just comes into view
		vp.SetYOffset(currentOffset - (distance + (vp.Height - edge)) + 1)
	} else {
		// we should scroll up
		vp.SetYOffset(currentOffset - distance - edge)
	}
}