/**
 * CodeEditor - CodeMirror 6 wrapper with Emmet support
 */
import { EditorState, Prec } from "@codemirror/state";
import { EditorView, keymap, placeholder } from "@codemirror/view";
import { defaultKeymap, historyKeymap, indentMore, indentLess, undo, redo } from "@codemirror/commands";
import { history } from "@codemirror/commands";
import { html } from "@codemirror/lang-html";
import { css } from "@codemirror/lang-css";
import { autocompletion } from "@codemirror/autocomplete";
import { abbreviationTracker, expandAbbreviation } from "@emmetio/codemirror6-plugin";
import { HighlightStyle, syntaxHighlighting } from "@codemirror/language";
import { tags } from "@lezer/highlight";

// Custom theme with purple accent colors (matching app completed state)
const crispyTheme = EditorView.theme(
	{
		"&": {
			backgroundColor: "#262630",
			color: "#c8c8d0"
		},
		".cm-content": {
			caretColor: "#9b6dd4"
		},
		".cm-cursor, .cm-dropCursor": {
			borderLeftColor: "#9b6dd4"
		},
		"&.cm-focused > .cm-scroller > .cm-selectionLayer .cm-selectionBackground, .cm-selectionBackground, .cm-content ::selection": {
			backgroundColor: "#3e3e4a"
		},
		".cm-panels": {
			backgroundColor: "#262630",
			color: "#c8c8d0"
		},
		".cm-searchMatch": {
			backgroundColor: "#3e3e4a",
			outline: "1px solid #9b6dd4"
		},
		".cm-searchMatch.cm-searchMatch-selected": {
			backgroundColor: "rgba(155, 109, 212, 0.3)"
		},
		".cm-activeLine": {
			backgroundColor: "#2e2e3a"
		},
		".cm-selectionMatch": {
			backgroundColor: "#3e3e4a"
		},
		".cm-gutters": {
			backgroundColor: "#262630",
			color: "#808090",
			border: "none"
		},
		".cm-activeLineGutter": {
			backgroundColor: "#2e2e3a"
		},
		".cm-lineNumbers .cm-gutterElement": {
			color: "#808090"
		}
	},
	{ dark: true }
);

// Default syntax highlighting (blue accent)
const defaultHighlight = HighlightStyle.define([
	{ tag: tags.keyword, color: "#c9a6eb" },
	{ tag: tags.operator, color: "#cdd6f4" },
	{ tag: tags.variableName, color: "#89b4fa" },
	{ tag: tags.propertyName, color: "#89b4fa" },
	{ tag: tags.attributeName, color: "#89b4fa" },
	{ tag: tags.className, color: "#89b4fa" },
	{ tag: tags.tagName, color: "#c9a6eb" },
	{ tag: tags.string, color: "#a6e3a1" },
	{ tag: tags.number, color: "#fab387" },
	{ tag: tags.bool, color: "#fab387" },
	{ tag: tags.null, color: "#fab387" },
	{ tag: tags.comment, color: "#6c7086", fontStyle: "italic" },
	{ tag: tags.bracket, color: "#cdd6f4" },
	{ tag: tags.punctuation, color: "#cdd6f4" },
	{ tag: tags.definition(tags.variableName), color: "#89b4fa" },
	{ tag: tags.function(tags.variableName), color: "#89b4fa" },
	{ tag: tags.atom, color: "#c9a6eb" },
	{ tag: tags.unit, color: "#a6e3a1" },
	{ tag: tags.color, color: "#f9e2af" }
]);

// CSS section highlighting (purple selectors)
const cssHighlight = HighlightStyle.define([
	{ tag: tags.keyword, color: "#c9a6eb" },
	{ tag: tags.operator, color: "#cdd6f4" },
	{ tag: tags.variableName, color: "#c9a6eb" },
	{ tag: tags.propertyName, color: "#89b4fa" },
	{ tag: tags.attributeName, color: "#89b4fa" },
	{ tag: tags.className, color: "#c9a6eb" },
	{ tag: tags.tagName, color: "#c9a6eb" },
	{ tag: tags.string, color: "#a6e3a1" },
	{ tag: tags.number, color: "#fab387" },
	{ tag: tags.bool, color: "#fab387" },
	{ tag: tags.null, color: "#fab387" },
	{ tag: tags.comment, color: "#6c7086", fontStyle: "italic" },
	{ tag: tags.bracket, color: "#cdd6f4" },
	{ tag: tags.punctuation, color: "#cdd6f4" },
	{ tag: tags.definition(tags.variableName), color: "#c9a6eb" },
	{ tag: tags.function(tags.variableName), color: "#89b4fa" },
	{ tag: tags.atom, color: "#c9a6eb" },
	{ tag: tags.unit, color: "#a6e3a1" },
	{ tag: tags.color, color: "#f9e2af" }
]);

// Get highlight style based on section
function getHighlightForSection(section) {
	if (section === "css") return cssHighlight;
	return defaultHighlight;
}

// Get theme with section-specific highlighting
export function getEditorTheme(section) {
	return [crispyTheme, syntaxHighlighting(getHighlightForSection(section))];
}

// Default combined theme export (for backwards compatibility)
export const crispyEditorTheme = [crispyTheme, syntaxHighlighting(defaultHighlight)];

// Custom overrides for editor styling
const editorTheme = EditorView.theme(
	{
		"&": {
			height: "100%",
			fontSize: "14px"
		},
		".cm-content": {
			fontFamily: "'JetBrains Mono', 'Fira Code', monospace",
			padding: "12px 0"
		},
		".cm-line": {
			padding: "0 12px"
		}
	},
	{ dark: true }
);

export class CodeEditor {
	constructor(container, options = {}) {
		this.container = container;
		this.options = options;
		this.view = null;
		this.mode = options.mode || "css";
		this.section = options.section || null;
		this.onChange = options.onChange || (() => {});
	}

	/**
	 * Initialize the editor
	 */
	init(initialValue = "") {
		// Clear container
		this.container.innerHTML = "";

		// Get language extension based on mode
		const langExtension = this.mode === "html" ? html() : css();

		// Build extensions array
		const extensions = [
			langExtension,
			getEditorTheme(this.section),
			editorTheme,
			// History for undo/redo
			history(),
			// Emmet abbreviation tracking
			abbreviationTracker(),
			// High priority keymap for Emmet
			Prec.highest(
				keymap.of([
					{
						key: "Tab",
						run: expandAbbreviation
					}
				])
			),
			// Standard keymaps including history (Ctrl+Z, Ctrl+Shift+Z)
			keymap.of([...historyKeymap, { key: "Tab", run: indentMore }, { key: "Shift-Tab", run: indentLess }, ...defaultKeymap]),
			autocompletion({
				activateOnTyping: true,
				maxRenderedOptions: 10
			}),
			EditorView.updateListener.of((update) => {
				if (update.docChanged) {
					this.onChange(this.getValue());
				}
			}),
			EditorView.lineWrapping
		];

		// Add placeholder if provided
		if (this.options.placeholder) {
			extensions.push(placeholder(this.options.placeholder));
		}

		// Create editor state
		const state = EditorState.create({
			doc: initialValue,
			extensions
		});

		// Create editor view
		this.view = new EditorView({
			state,
			parent: this.container
		});

		return this;
	}

	/**
	 * Get current editor value
	 */
	getValue() {
		return this.view ? this.view.state.doc.toString() : "";
	}

	/**
	 * Set editor value (preserves history)
	 */
	setValue(value) {
		if (!this.view) return;

		this.view.dispatch({
			changes: {
				from: 0,
				to: this.view.state.doc.length,
				insert: value
			}
		});
	}

	/**
	 * Set editor value and clear history (for lesson switching)
	 */
	setValueAndClearHistory(value) {
		this.init(value);
	}

	/**
	 * Set editor mode (html or css)
	 */
	setMode(mode) {
		if (this.mode === mode) return;

		this.mode = mode;
		const currentValue = this.getValue();
		this.init(currentValue);
	}

	/**
	 * Set section for theme (css, html, tailwind)
	 */
	setSection(section) {
		if (this.section === section) return;

		this.section = section;
		const currentValue = this.getValue();
		this.init(currentValue);
	}

	/**
	 * Focus the editor
	 */
	focus() {
		if (this.view) {
			this.view.focus();
		}
	}

	/**
	 * Undo last change
	 */
	undo() {
		if (this.view) {
			undo(this.view);
		}
	}

	/**
	 * Redo last undone change
	 */
	redo() {
		if (this.view) {
			redo(this.view);
		}
	}

	/**
	 * Destroy the editor
	 */
	destroy() {
		if (this.view) {
			this.view.destroy();
			this.view = null;
		}
	}
}