//
//  TableOfContentsTests.swift
//  GeminiFormatTests
//
//  Created by Shadowfacts on 12/19/20.
//

import XCTest
@testable import GeminiFormat

class TableOfContentsTests: XCTestCase {
    
    func testOneHeading() {
        let one = Document(url: URL(string: "gemini://example.com/")!, lines: [
            .heading("Heading", level: .h1)
        ])
        XCTAssertEqual(TableOfContents(document: one).entries, [
            .init(line: .heading("Heading", level: .h1), lineIndex: 0)
        ])
        
        let two = Document(url: URL(string: "gemini://example.com/")!, lines: [
            .heading("Heading", level: .h2)
        ])
        XCTAssertEqual(TableOfContents(document: two).entries, [
            .init(line: .heading("Heading", level: .h2), lineIndex: 0)
        ])
        
        let three = Document(url: URL(string: "gemini://example.com/")!, lines: [
            .heading("Heading", level: .h3)
        ])
        XCTAssertEqual(TableOfContents(document: three).entries, [
            .init(line: .heading("Heading", level: .h3), lineIndex: 0)
        ])
    }
    
    func testMultipleTopLevelHeadings() {
        let doc = Document(url: URL(string: "gemini://example.com")!, lines: [
            .heading("One", level: .h1),
            .heading("Two", level: .h1),
        ])
        XCTAssertEqual(TableOfContents(document: doc).entries, [
            .init(line: .heading("One", level: .h1), lineIndex: 0),
            .init(line: .heading("Two", level: .h1), lineIndex: 1)
        ])
    }
    
    func testNestedHeadings() {
        let doc = Document(url: URL(string: "gemini://example.com")!, lines: [
            .heading("One", level: .h1),
            .heading("Two", level: .h2),
        ])
        let entries = TableOfContents(document: doc).entries
        XCTAssertEqual(entries.count, 1)
        XCTAssertEqual(entries[0].line, .heading("One", level: .h1))
        XCTAssertEqual(entries[0].lineIndex, 0)
        XCTAssertEqual(entries[0].children, [
            .init(line: .heading("Two", level: .h2), lineIndex: 1)
        ])
    }
    
    func testTriplyNestedHeadings() {
        let doc = Document(url: URL(string: "gemini://example.com")!, lines: [
            .heading("One", level: .h1),
            .heading("Two", level: .h2),
            .heading("Three", level: .h3),
        ])
        let entries = TableOfContents(document: doc).entries
        XCTAssertEqual(entries.count, 1)
        XCTAssertEqual(entries[0].line, .heading("One", level: .h1))
        XCTAssertEqual(entries[0].lineIndex, 0)
        XCTAssertEqual(entries[0].children.count, 1)
        XCTAssertEqual(entries[0].children[0].line, .heading("Two", level: .h2))
        XCTAssertEqual(entries[0].children[0].lineIndex, 1)
        XCTAssertEqual(entries[0].children[0].children, [
            .init(line: .heading("Three", level: .h3), lineIndex: 2)
        ])
    }
    
    func testMultipleTopLevelSections() {
        let doc = Document(url: URL(string: "gemini://example.com")!, lines: [
            .heading("Top Level One", level: .h1),
            .heading("A", level: .h2),
            .heading("Top Level Two", level: .h1),
            .heading("B", level: .h2),
        ])
        let entries = TableOfContents(document: doc).entries
        XCTAssertEqual(entries.count, 2)
        let first = entries[0]
        XCTAssertEqual(first.line, .heading("Top Level One", level: .h1))
        XCTAssertEqual(first.lineIndex, 0)
        XCTAssertEqual(first.children, [
            .init(line: .heading("A", level: .h2), lineIndex: 1)
        ])
        let second = entries[1]
        XCTAssertEqual(second.line, .heading("Top Level Two", level: .h1))
        XCTAssertEqual(second.lineIndex, 2)
        XCTAssertEqual(second.children, [
            .init(line: .heading("B", level: .h2), lineIndex: 3)
        ])
    }
    
    func testMultipleNestedSections() {
        let doc = Document(url: URL(string: "gemini://example.com")!, lines: [
            .heading("Top Level", level: .h1),
            .heading("A", level: .h2),
            .heading("Third Level", level: .h3),
            .heading("B", level: .h2),
            .heading("Third Level 2", level: .h3),
        ])
        let entries = TableOfContents(document: doc).entries
        XCTAssertEqual(entries.count, 1)
        let topLevel = entries[0]
        XCTAssertEqual(topLevel.line, .heading("Top Level", level: .h1))
        XCTAssertEqual(topLevel.lineIndex, 0)
        let children = topLevel.children
        XCTAssertEqual(children.count, 2)
        let first = children[0]
        XCTAssertEqual(first.line, .heading("A", level: .h2))
        XCTAssertEqual(first.lineIndex, 1)
        XCTAssertEqual(first.children, [
            .init(line: .heading("Third Level", level: .h3), lineIndex: 2)
        ])
        let second = children[1]
        XCTAssertEqual(second.line, .heading("B", level: .h2))
        XCTAssertEqual(second.lineIndex, 3)
        XCTAssertEqual(second.children, [
            .init(line: .heading("Third Level 2", level: .h3), lineIndex: 4)
        ])
    }
    
    func testNonH1TopLevelSections() {
        let doc = Document(url: URL(string: "gemini://example.com")!, lines: [
            .heading("A", level: .h2),
            .heading("B", level: .h3),
            .heading("C", level: .h1),
        ])
        let entries = TableOfContents(document: doc).entries
        XCTAssertEqual(entries.count, 2)
        let first = entries[0]
        XCTAssertEqual(first.line, .heading("A", level: .h2))
        XCTAssertEqual(first.lineIndex, 0)
        XCTAssertEqual(first.children, [
            .init(line: .heading("B", level: .h3), lineIndex: 1)
        ])
        XCTAssertEqual(entries[1], .init(line: .heading("C", level: .h1), lineIndex: 2))
    }

}