import Foundation
import SwiftUI
import Testing
@testable import OrgSwift
@testable import OrgSwiftUI

@MainActor
struct OrgMathLayoutTests {

    private func layout(_ source: String) -> OrgLayout {
        OrgLayoutBuilder(options: .init(), styler: PlainOrgCodeStyler(), keywords: .init())
            .layout(OrgParser.parse(source))
    }

    @Test func aLatexBlockIsAMathBlock() {
        let raw = "\\begin{align}\nx &= 1\n\\end{align}"
        guard case .math(let math) = layout(raw).blocks.first else {
            Issue.record("expected math, got \(layout(raw).blocks)"); return
        }
        #expect(math == OrgMath(tex: raw, display: true, source: raw))
    }

    @Test func aParagraphThatIsOneDisplayExpressionIsAMathBlock() {
        guard case .math(let math) = layout(#"\[ x^2 \]"#).blocks.first else {
            Issue.record("expected math"); return
        }
        #expect(math.tex == " x^2 ")
        guard case .paragraph = layout(#"so \[ x^2 \]"#).blocks.first else {
            Issue.record("prose around display math keeps the paragraph"); return
        }
    }

    @Test func inlineMathIsItsSourceMarkedWithTheExpression() {
        guard case .paragraph(let text) = layout("a $x$ b").blocks.first else {
            Issue.record("expected a paragraph"); return
        }
        #expect(String(text.characters) == "a $x$ b")
        let marked = text.runs.compactMap { $0[OrgMathAttribute.self] }
        #expect(marked == [OrgMath(tex: "x", display: false, source: "$x$")])
    }

    @Test func anExpressionSplitByATransformDrawsOnce() {
        let builder = OrgLayoutBuilder(options: .init(), styler: PlainOrgCodeStyler(), keywords: .init(),
                                       textTransform: { text in
            if let range = text.range(of: "#1") { text[range].link = URL(string: "https://x.test/1") }
        })
        guard case .paragraph(let text) = builder.layout(OrgParser.parse("a $x#1y$ b")).blocks.first else {
            Issue.record("expected a paragraph"); return
        }
        var drawn = 0
        _ = orgText(text) { _ in
            drawn += 1
            return Text(verbatim: "·")
        }
        #expect(drawn == 1)
    }

    @Test func orgTextDrawsEachExpression() {
        guard case .paragraph(let text) = layout("$x$$x$ and $y$").blocks.first else {
            Issue.record("expected a paragraph"); return
        }
        var drawn: [String] = []
        _ = orgText(text) { math in
            drawn.append(math.tex)
            return Text(verbatim: "·")
        }
        #expect(drawn.sorted() == ["x", "y"])
        _ = orgText(text, math: nil)
    }
}