import * as CF from '@efforting.tech/data/field-configuration-factories';

import { readFileSync } from 'node:fs';
import { inspect } from 'node:util';

import { Indention_Mode, Text_Settings } from '@efforting.tech/text/basic-tree';

// TODO: Move into string helper module
function string_has_contents(str) {
	return /\S/.test(str);
}

function *indented_line_iterator(settings, text) {

	let line_no = settings.first_line;
	let index = 0;
	const { indention_tabulator_width } = settings;

	switch (settings.indention_mode) {
		case Indention_Mode.symbols.TABULATORS: {
			for (const line of text.matchAll(/^(\t*)(.*)$/gm)) {
				const [raw, tabs, remaining] = line;
				yield { raw, indent: tabs.length, line: remaining, line_no: line_no++, index: index++};
			}
			break;
		}
		case Indention_Mode.symbols.SPACES: {
			for (const line of text.matchAll(/^([ ]*)(.*)$/gm)) {
				const [raw, spaces, remaining] = line;

				if ((spaces.length % indention_tabulator_width) !== 0) {
					throw new Error('Unaligned indention');	//TODO - proper error
				}
				yield { raw, indent: Math.floor(spaces.length / indention_tabulator_width), line: remaining, line_no: line_no++, index: index++};
			}
			break;
		}
		default:
			throw new Error('Unsupported indention mode');	//TODO - proper error

	}


}


const ts = Text_Settings.load({
	indention_mode: 'TABULATORS',
});

const example_string =
`branch1
	leaf1
	leaf2

branch2
	sub-branch1
		leaf3
		leaf4


	sub-branch2
		leaf5

branch3
		dual-indented

`;


class Text_Node {
	constructor(text_settings, line=undefined, indent=0, line_no=undefined, index=undefined, raw=undefined, parent=undefined) {
		Object.assign(this, { text_settings, line, indent, line_no, index, raw, parent, children: [] });
	}
}


const root = new Text_Node(ts);

// NOTE: This first Text_Node is not added to the tree, it serves as an initial cursor only.
let current = new Text_Node(root.text_settings, undefined, 0, undefined, undefined, undefined, root);


for (const line_info of indented_line_iterator(ts, example_string)) {

	// TODO: Implement other variants than inherit-from-previous
	const indent = string_has_contents(line_info.line) ? line_info.indent : current.indent;

	const delta_indent = indent - current.indent;

	if (delta_indent == 0) {
		const pending = new Text_Node(current.text_settings, undefined, current.indent, undefined, undefined, undefined, current.parent);	// Partial insertion - same level
		if (current.parent) {
			current.parent.children.push(pending);
		}
		current = pending;
	} else if (delta_indent > 0) {
		for (let i=0; i<delta_indent; i++) {
			const pending = new Text_Node(current.text_settings, undefined, current.indent + 1, undefined, undefined, undefined, current);	// Partial insertion
			current.children.push(pending);
			current = pending;
		}
	} else {
		for (let i=0; i>delta_indent; i--) {
			current = current.parent;
		}

		const pending = new Text_Node(current.text_settings, undefined, current.indent, undefined, undefined, undefined, current.parent);	// Partial insertion - same level
		if (current.parent) {
			current.parent.children.push(pending);
		}
		current = pending;
	}

	// Fill in partial insertion
	Object.assign(current, {
		line: line_info.line,
		line_no: line_info.line_no,
		index: line_info.index,
		raw: line_info.raw,
	});


}


function debug_dump(node, level=0) {
	console.log(`${"  ".repeat(level)}[${node.line_no ?? '-'}] ${inspect(node.line)}`);
	for (const child of node.children) {
		debug_dump(child, level+1);
	}
}

debug_dump(root);
/*

[-] undefined
  [1] 'branch1'
    [2] 'leaf1'
    [3] 'leaf2'
    [4] ''
  [5] 'branch2'
    [6] 'sub-branch1'
      [7] 'leaf3'
      [8] 'leaf4'
      [9] ''
      [10] ''
    [11] 'sub-branch2'
      [12] 'leaf5'
      [13] ''
  [14] 'branch3'
    [-] undefined
      [15] 'dual-indented'
      [16] ''
      [17] ''

*/