package core

import (
	"strings"
)

const CommandOutputExitMessage = "Press ENTER to continue"
const CommandOutputScrollMessage = "Use j/k to scroll"

type CommandOutput struct {
	Title        string
	Lines        []string
	ScrollOffset int // Not implemented yet
	// Height is computing via lines and title
	Inline  bool // Show inline instead of the window
	IsError bool
}

// CommandOutput.Height: Compute the height (in lines) based on the line count, and title.
func (c *CommandOutput) Height() int {
	if c.Inline {
		return 1
	}

	var h int
	h += len(c.Lines)
	if strings.TrimSpace(c.Title) != "" {
		h++
	}

	// Padding:
	// +1 for 'enter key...' message
	// +1 for top bar (border)
	h += 2

	return h
}

// CommandOutput.IsActive: Is the command output in a state that should be displayed.
func (c *CommandOutput) IsActive() bool {
	return len(c.Lines) > 0
}

// maxOutputWindowHeight: Calculates the max height of the output window. This is simply
// just 3/4 of the terminal height. This allows the title to always be shown, but also
// allows the user to not totally lose mental context when viewing a large output.
func maxOutputWindowHeight(termHeight int) int {
	return int(float64(termHeight) * 0.75)
}

// CommandOutput.Viewport: Returns a list of the lines in the current viewport, depends on
// the height of the terminal. This function should be in place of the Lines property.
func (c *CommandOutput) Viewport(height int) []string {
	start := c.ScrollOffset
	end := maxOutputWindowHeight(height) + start

	// Clamp end to available lines
	if end > len(c.Lines) {
		end = len(c.Lines)
	}

	return c.Lines[start:end]
}

// CommandOutput.ScrollDown: Manages the scrolling down logic and handles bounds checks.
// This function depends on the height on the terminal.
func (c *CommandOutput) ScrollDown(height int) {
	if (c.ScrollOffset + maxOutputWindowHeight(height)) < len(c.Lines) {
		c.ScrollOffset++
	}
}

// CommandOutput.ScrollUp: Manages the scrolling up logic and handles bounds checks.
func (c *CommandOutput) ScrollUp() {
	if c.ScrollOffset > 0 {
		c.ScrollOffset--
	}
}