@testable import PureYAML
import Testing

/// In a flow mapping the value is a flow node and may sit on any line: flow is line insensitive,
/// unlike a block mapping whose value must be on the key's line or an indented block below it.
/// A value after `:` on the next line is the value, not a null. Pretty-printed JSON (a YAML 1.2
/// superset) relies on this throughout, which is why it must hold. Only a flow terminator leaves
/// the value empty.
@Suite("Flow multi-line value")
struct FlowMultilineValueTests {
    @Test("A flow mapping value on the line after the colon is the value")
    func test_valueOnNextLine() throws {
        #expect(try PureYAML.parse("{\"a\":\n\"b\"}") == .mapping(.init([
            .init(key: "a", value: .string("b")),
        ])))
    }

    @Test("Several flow values, each on its own line, each bind to their key")
    func test_severalNextLineValues() throws {
        let yaml = "{\n\"a\":\n  \"x\",\n\"b\":\n  \"y\"\n}"
        #expect(try PureYAML.parse(yaml) == .mapping(.init([
            .init(key: "a", value: .string("x")),
            .init(key: "b", value: .string("y")),
        ])))
    }

    @Test("A flow value that is itself a flow node spanning lines is parsed")
    func test_nextLineValueIsFlowNode() throws {
        #expect(try PureYAML.parse("{\"a\":\n[1, 2]}") == .mapping(.init([
            .init(key: "a", value: .sequence([.int(1), .int(2)])),
        ])))
    }

    @Test("Near miss: a flow value omitted before a terminator is null, not the next entry")
    func test_emptyFlowValueStaysNull() throws {
        #expect(try PureYAML.parse("{\"a\": , \"b\": \"c\"}") == .mapping(.init([
            .init(key: "a", value: .null),
            .init(key: "b", value: .string("c")),
        ])))
    }

    @Test("Pretty-printed JSON (an array of objects with values on their own lines) parses")
    func test_prettyPrintedJSON() throws {
        let yaml = "[\n  {\n    \"k\":\n      \"v\"\n  }\n]"
        #expect(try PureYAML.parse(yaml) == .sequence([
            .mapping(.init([.init(key: "k", value: .string("v"))])),
        ]))
    }
}