import {
	App,
	Editor,
	EditorChange,
	EditorPosition,
	EditorTransaction,
	MarkdownFileInfo,
	MarkdownView,
} from 'obsidian'
import BindThemPlugin from './main'
import { Heading } from './Entities'
import { getMainSelection, selectionToRange } from './Utils'
import { HEADING_REGEX } from './Constants'

/**
 * ToggleHeading provides commands to toggle markdown heading levels
 */
export class ToggleHeading {
	public app: App
	private plugin: BindThemPlugin

	constructor(app: App, plugin: BindThemPlugin) {
		this.app = app
		this.plugin = plugin
	}

	/**
	 * Create a change to set the heading level for a specific line
	 */
	private setHeading(
		editor: Editor,
		heading: Heading,
		line: number
	): EditorChange {
		const headingStr = '#'.repeat(heading)
		const text = editor.getLine(line)
		const matches = HEADING_REGEX.exec(text)!

		const from: EditorPosition = {
			line: line,
			ch: 0,
		}
		const to: EditorPosition = {
			line: line,
			ch: matches[1].length + matches[2].length,
		}

		const replacementStr = heading === Heading.NORMAL ? '' : headingStr + ' '

		return {
			from: from,
			to: to,
			text: replacementStr,
		}
	}

	/**
	 * Get the heading level of a specific line
	 */
	private getHeadingOfLine(editor: Editor, line: number): Heading {
		const text = editor.getLine(line)
		const matches = HEADING_REGEX.exec(text)!

		return matches[1].length as Heading
	}

	/**
	 * Toggle heading for the current selection(s)
	 * If the line already has the specified heading, remove it (set to NORMAL)
	 */
	public toggleHeading(
		editor: Editor,
		view: MarkdownView | MarkdownFileInfo,
		heading: Heading
	): void {
		const selections = editor.listSelections()
		const mainSelection = getMainSelection(editor)
		const mainRange = selectionToRange(mainSelection)

		const mainHeading = this.getHeadingOfLine(editor, mainRange.from.line)
		const targetHeading = heading === mainHeading ? Heading.NORMAL : heading

		const changes: Array<EditorChange> = []

		// Collect unique lines from all selections
		const linesToSet: Set<number> = new Set()
		for (const selection of selections) {
			const range = selectionToRange(selection)
			for (let line = range.from.line; line <= range.to.line; line++) {
				linesToSet.add(line)
			}
		}

		// Create changes for each line
		for (const line of linesToSet) {
			if (editor.getLine(line) === '') {
				continue
			}
			changes.push(this.setHeading(editor, targetHeading, line))
		}

		const transaction: EditorTransaction = {
			changes: changes,
		}

		editor.transaction(transaction, 'ToggleHeading' + heading.toString())
	}

	/**
	 * Toggle heading with stripping of inline formatting
	 * This removes bold/italic formatting when toggling headings
	 */
	public toggleHeadingWithStrip(
		editor: Editor,
		view: MarkdownView | MarkdownFileInfo,
		level: number
	): void {
		const cursor = editor.getCursor()
		const line = editor.getLine(cursor.line)
		const match = line.match(/^(#+)\s(.*)/)
		
		let content = line
		let currentLevel = 0
		
		if (match) {
			currentLevel = match[1].length
			content = match[2]
		}
		
		// Strip bold and italic formatting
		content = content
			.replace(/(\*\*|__)(.*?)\1/g, '$2')
			.replace(/(\*|_)(.*?)\1/g, '$2')
		
		editor.setLine(
			cursor.line,
			currentLevel === level ? content : '#'.repeat(level) + ' ' + content
		)
	}
}