package editor

import (
	"fmt"
	"strings"

	"git.gophernest.net/azpect/TextEditor/internal/action"
)

func posInsideSelection(m Model, col, line int) bool {
	switch m.Mode() {
	case action.VisualLineMode:
		startY := min(m.AnchorY(), m.CursorY())
		endY := max(m.AnchorY(), m.CursorY())
		return line >= startY && line <= endY

	case action.VisualMode:
		ax := m.AnchorX()
		ay := m.AnchorY()

		cx := m.CursorX()
		cy := m.CursorY()

		// Normalize so start is always before end in document order
		var startX, startY, endX, endY int
		if ay < cy || (ay == cy && ax <= cx) {
			startX, startY = ax, ay
			endX, endY = cx, cy
		} else {
			startX, startY = cx, cy
			endX, endY = ax, ay
		}

		// Position is inside if it falls within [start, end] inclusive
		afterStart := line > startY || (line == startY && col >= startX)
		beforeEnd := line < endY || (line == endY && col <= endX)
		return afterStart && beforeEnd

	case action.VisualBlockMode:
		startX := min(m.AnchorX(), m.CursorX())
		startY := min(m.AnchorY(), m.CursorY())
		endX := max(m.AnchorX(), m.CursorX())
		endY := max(m.AnchorY(), m.CursorY())

		return col >= startX && col <= endX &&
			line >= startY && line <= endY

	default:
		return false
	}
}

func posIsAnchor(m Model, col, line int) bool {
	ax := m.AnchorX()
	ay := m.AnchorY()
	return col == ax && line == ay
}

func (m Model) View() string {
	var view strings.Builder

	viewportHeight := m.win_h - 1 // -1 for status bar
	start := m.ScrollY()
	end := m.ScrollY() + viewportHeight

	for i := start; i < end; i++ {

		if i < m.LineCount() {

			var (
				gutter      string
				currentLine bool = false
				lineNumber  int
			)
			if i > m.CursorY() {
				lineNumber = i - m.CursorY()
				gutter = fmt.Sprintf("%*d ", m.Settings().GutterSize-1, lineNumber)
			} else if i < m.CursorY() {
				lineNumber = m.CursorY() - i
				gutter = fmt.Sprintf("%*d ", m.Settings().GutterSize-1, lineNumber)
			} else {
				lineNumber = i + 1
				currentLine = true
				if lineNumber < 100 {
					gutter = fmt.Sprintf("%*d  ", m.Settings().GutterSize-2, lineNumber)
				} else {
					gutter = fmt.Sprintf("%*d ", m.Settings().GutterSize-1, lineNumber)
				}
			}
			view.WriteString(m.gutterStyle(currentLine).Render(gutter))

			runes := []rune(m.Line(i))
			for x := 0; x <= len(runes); x++ {
				if m.CursorY() == i && m.CursorX() == x {
					if x < len(runes) {
						view.WriteString(m.cursorStyle().Render(string(runes[x])))
					} else {
						view.WriteString(m.cursorStyle().Render(" "))
					}
				} else if x < len(runes) {
					if m.IsVisualMode() && posIsAnchor(m, x, i) {
						view.WriteString(m.visualAnchorStyle().Render(string(runes[x])))
					} else if m.IsVisualMode() && posInsideSelection(m, x, i) {
						view.WriteString(m.visualHighlightStyle().Render(string(runes[x])))
					} else {
						view.WriteRune(runes[x])
					}
					// To highlight blank lines when in visual mode
				} else if m.IsVisualMode() && posInsideSelection(m, x, i) {
					view.WriteString(m.visualHighlightStyle().Render(" "))
				}
			}
		} else {
			format := fmt.Sprintf("%%-%ds ", m.Settings().GutterSize-1)
			fmt.Fprintf(&view, format, "~")
		}

		view.WriteString("\n")
	}

	// Draw status bar
	var modeString string
	switch m.Mode() {
	case action.NormalMode:
		modeString = "NORMAL"
	case action.InsertMode:
		modeString = "INSERT"
	case action.CommandMode:
		modeString = "COMMAND"
	case action.VisualMode:
		modeString = "VISUAL"
	case action.VisualLineMode:
		modeString = "V-LINE"
	case action.VisualBlockMode:
		modeString = "V-BLOCK"
	}

	// DEBUG BAR! Def not the final bar
	var bar string
	if m.Mode() == action.CommandMode {
		bar = fmt.Sprintf(" %6s | %d:%d (%d:%d) :%s ", modeString, m.cursor.x, m.cursor.y, m.win_w, m.win_h, m.command)
	} else if m.IsVisualMode() {
		bar = fmt.Sprintf(" %6s | %d:%d (%d:%d) <%d, %d> ", modeString, m.cursor.x, m.cursor.y, m.win_w, m.win_h, m.AnchorX(), m.AnchorY())
	} else {
		bar = fmt.Sprintf(" %6s | %d:%d (%d:%d) | %s | %+v | %d", modeString, m.cursor.x, m.cursor.y, m.win_w, m.win_h, m.input.Pending(), m.insertKeys, m.insertCount)
	}

	view.WriteString(bar)

	return view.String()
}