import XCTest
@testable import LChatCore

// 🤖 Parity + drift gates for the default-command rule (the web's apps.js
// defaultCommandFor + chat.js composer routing). The drift gates PARSE
// web/static/apps/todo.js from the repo, so changing the web app's
// defaultCommand, placeholder, or chatIntro fails here until Swift follows.
final class AppDefaultCommandTests: XCTestCase {
    private var repoRoot: URL {
        URL(fileURLWithPath: #filePath)
            .deletingLastPathComponent()                // Tests/LChatCoreTests
            .deletingLastPathComponent()                // Tests
            .deletingLastPathComponent()                // LChatCore
            .deletingLastPathComponent()                // ios
            .deletingLastPathComponent()                // repo
    }

    // The first "…"-quoted value after `key:` in a JS source.
    private func jsString(_ source: String, key: String) -> String? {
        guard let re = try? NSRegularExpression(pattern: key + "\\s*:\\s*\\n?\\s*\"([^\"]+)\""),
              let m = re.firstMatch(in: source, range: NSRange(source.startIndex..., in: source)),
              let r = Range(m.range(at: 1), in: source) else { return nil }
        return String(source[r])
    }

    // ---- gating (apps.js defaultCommandFor) --------------------------------

    func testSpecGating() {
        XCTAssertNotNil(AppDefaultCommand.spec(appID: "todo", hasBot: false))
        XCTAssertNil(AppDefaultCommand.spec(appID: "todo", hasBot: true),
                     "an LLM member makes plain text a real message again")
        XCTAssertNotNil(AppDefaultCommand.spec(appID: "remind", hasBot: false))
        XCTAssertNil(AppDefaultCommand.spec(appID: "remind", hasBot: true))
        XCTAssertNil(AppDefaultCommand.spec(appID: nil, hasBot: false))
    }

    // Reminders' verb is its GLOBAL /remind (the web made it the default — no
    // local twin), so it both routes and leads the thread's typeahead.
    func testRemindSpecRoutesItsGlobalVerb() throws {
        let dc = try XCTUnwrap(AppDefaultCommand.spec(appID: "remind", hasBot: false))
        XCTAssertEqual(AppDefaultCommand.routing("call mum in 2h", spec: dc), .event("call mum in 2h"))
        XCTAssertEqual(AppDefaultCommand.routing("/remind call mum in 2h", spec: dc), .event("call mum in 2h"))
        XCTAssertEqual(AppDefaultCommand.routing("/remind", spec: dc), .swallow)
        XCTAssertEqual(AppDefaultCommand.routing("/theme lagoon", spec: dc), .passthrough)
        XCTAssertEqual(AppDefaultCommand.localCommands(appID: "remind").map(\.name), ["/remind"])
    }

    func testRemindSpecMatchesRemindJS() throws {
        let js = try String(contentsOf: repoRoot.appending(path: "web/static/apps/remind.js"),
                            encoding: .utf8)
        let dc = try XCTUnwrap(AppDefaultCommand.specs["remind"])
        XCTAssertEqual(jsString(js, key: "defaultCommand"), dc.verbs.first,
                       "Swift default command has drifted from remind.js")
        XCTAssertEqual(jsString(js, key: "composerPlaceholder"), dc.placeholder,
                       "Swift placeholder has drifted from remind.js")
        XCTAssertEqual(jsString(js, key: "chatIntro"), AppChatProjection.intros["remind"],
                       "native Reminders intro has drifted from remind.js chatIntro")
        // The "when?" push-back mirrors the web's usage reply wording.
        XCTAssertTrue(js.contains(AppDefaultCommand.remindWhenPrompt),
                      "remindWhenPrompt has drifted from remind.js's usage reply")
    }

    // ---- routing (chat.js composer) ----------------------------------------

    func testPlainTextRoutes() throws {
        let dc = try XCTUnwrap(AppDefaultCommand.spec(appID: "todo", hasBot: false))
        XCTAssertEqual(AppDefaultCommand.routing("buy milk", spec: dc), .event("buy milk"))
        XCTAssertEqual(AppDefaultCommand.routing("  buy milk  ", spec: dc), .event("buy milk"))
        XCTAssertEqual(AppDefaultCommand.routing("   ", spec: dc), .passthrough,
                       "empty drafts are the composer's no-op, not ours")
    }

    func testVerbsRouteWithVerbStripped() throws {
        let dc = try XCTUnwrap(AppDefaultCommand.spec(appID: "todo", hasBot: false))
        XCTAssertEqual(AppDefaultCommand.routing("/add buy milk", spec: dc), .event("buy milk"))
        XCTAssertEqual(AppDefaultCommand.routing("/ADD buy milk", spec: dc), .event("buy milk"))
        // The global alias adds here too, exactly as the web runs /todo in-thread.
        XCTAssertEqual(AppDefaultCommand.routing("/todo buy milk", spec: dc), .event("buy milk"))
    }

    func testBareVerbIsSwallowedNeverPosted() throws {
        // The web answers a bare verb with a private usage reply; native has no
        // notice surface, so it consumes the draft-send instead — under no
        // circumstances may "/add" land in the thread as a chat bubble.
        let dc = try XCTUnwrap(AppDefaultCommand.spec(appID: "todo", hasBot: false))
        XCTAssertEqual(AppDefaultCommand.routing("/add", spec: dc), .swallow)
        XCTAssertEqual(AppDefaultCommand.routing("/add   ", spec: dc), .swallow)
        XCTAssertEqual(AppDefaultCommand.routing("/todo", spec: dc), .swallow)
    }

    func testOtherSlashTextPassesThrough() throws {
        let dc = try XCTUnwrap(AppDefaultCommand.spec(appID: "todo", hasBot: false))
        XCTAssertEqual(AppDefaultCommand.routing("/theme lagoon", spec: dc), .passthrough,
                       "a leading / always means command, never content")
        XCTAssertEqual(AppDefaultCommand.routing("/added to cart", spec: dc), .passthrough,
                       "the verb must be its own token, not a prefix")
    }

    // ---- drift gates vs web/static/apps/todo.js ----------------------------

    func testSpecMatchesTodoJS() throws {
        let js = try String(contentsOf: repoRoot.appending(path: "web/static/apps/todo.js"),
                            encoding: .utf8)
        let dc = try XCTUnwrap(AppDefaultCommand.specs["todo"])
        XCTAssertEqual(jsString(js, key: "defaultCommand"), dc.verbs.first,
                       "Swift default command has drifted from todo.js")
        XCTAssertEqual(jsString(js, key: "composerPlaceholder"), dc.placeholder,
                       "Swift placeholder has drifted from todo.js")
    }

    func testChatIntroMatchesTodoJS() throws {
        let js = try String(contentsOf: repoRoot.appending(path: "web/static/apps/todo.js"),
                            encoding: .utf8)
        XCTAssertEqual(jsString(js, key: "chatIntro"), AppChatProjection.intros["todo"],
                       "native To-do intro has drifted from todo.js chatIntro")
    }
}