import XCTest
@testable import SaplingEditor

final class DocumentPresentationStateTests: XCTestCase {
    func testEveryLineHasExactlyOnePresentationState() {
        let source = "# Heading\n* [x] Done\nParagraph"
        let lineIndex = DocumentLineIndex(source: source)

        let presentation = DocumentPresentationState(lineIndex: lineIndex, activeLineIndex: 1)

        XCTAssertEqual(presentation.lines.count, 3)
        XCTAssertEqual(presentation.lineState(at: 0), .rendered)
        XCTAssertEqual(presentation.lineState(at: 1), .source)
        XCTAssertEqual(presentation.lineState(at: 2), .rendered)
        XCTAssertEqual(presentation.lines.filter { $0.state == .source }.map(\.line.index), [1])
        XCTAssertEqual(presentation.lines.filter { $0.state == .rendered }.map(\.line.index), [0, 2])
    }

    func testPresentationStateIsDeterministicForSameDocumentAndActiveLine() {
        let source = "# Heading\nThis has **bold** and `code`.\n* [ ] Todo"
        let lineIndex = DocumentLineIndex(source: source)

        let first = DocumentPresentationState(lineIndex: lineIndex, activeLineIndex: 2)
        let second = DocumentPresentationState(lineIndex: lineIndex, activeLineIndex: 2)

        XCTAssertEqual(first, second)
    }

    func testRenderedElementsAreSemantic() {
        let source = "# Heading\n* [x] Done\nSee [Docs](https://example.com)"
        let lineIndex = DocumentLineIndex(source: source)

        let presentation = DocumentPresentationState(lineIndex: lineIndex, activeLineIndex: 99)

        XCTAssertTrue(presentation.elements.contains {
            guard case .heading(let heading) = $0 else { return false }
            return heading.lineIndex == 0 && heading.level == 1
        })
        XCTAssertEqual(presentation.renderedTasks.map(\.checked), [true])
        XCTAssertTrue(presentation.elements.contains {
            guard case .link(let link) = $0 else { return false }
            return (source as NSString).substring(with: link.titleRange) == "Docs"
        })
    }

    func testCodeBlockIsRepresentedAsSemanticBlock() {
        let source = "Intro\n```swift\nlet value = 42\n```"
        let lineIndex = DocumentLineIndex(source: source)

        let presentation = DocumentPresentationState(lineIndex: lineIndex, activeLineIndex: 0)

        XCTAssertEqual(presentation.renderedCodeBlocks.count, 1)
        XCTAssertEqual(presentation.renderedCodeBlocks[0].lineIndexes, [1, 2, 3])
        XCTAssertEqual(
            (source as NSString).substring(with: presentation.renderedCodeBlocks[0].languageRange!),
            "swift"
        )
    }

    func testDirtyPresentationResolvesNearbyCodeBlockContext() {
        let source = "Intro\n```swift\nlet value = 42\n```"
        let lineIndex = DocumentLineIndex(source: source)

        let presentation = DocumentPresentationState(
            lineIndex: lineIndex,
            activeLineIndex: 0,
            lineIndexes: [2]
        )

        XCTAssertEqual(presentation.lines.count, 1)
        XCTAssertEqual(presentation.lines[0].state, .rendered)
        XCTAssertEqual(presentation.lines[0].renderPlan.kind, .codeBlockContent)
    }
}