import XCTest
@testable import LChatCore

// The GIF gate MessageBubble's AttachmentImage animates behind: the payload
// type says "GIF" (what /gif posts — see gif.js) and the decoded image really
// has frames to play. Single-frame GIFs and mislabelled stills stay photos.
final class AnimatedGIFTests: XCTestCase {
    func testIsGIFMatchesExactType() {
        XCTAssertTrue(Attachment(id: "a", type: "image/gif").isGIF)
        XCTAssertFalse(Attachment(id: "a", type: "image/jpeg").isGIF)
        XCTAssertFalse(Attachment(id: "a", type: "image/gif+xml").isGIF)
        XCTAssertFalse(Attachment(id: "a", type: nil).isGIF)
    }
}

#if canImport(AppKit) && !targetEnvironment(macCatalyst)
import AppKit
import ImageIO
import UniformTypeIdentifiers

final class GIFFrameCountTests: XCTestCase {
    func testAnimatedGIFReportsItsFrames() throws {
        let img = try XCTUnwrap(NSImage(data: makeImage(frames: 3, as: .gif)))
        XCTAssertEqual(img.gifFrameCount, 3)
    }

    func testSingleFrameGIFReportsOne() throws {
        let img = try XCTUnwrap(NSImage(data: makeImage(frames: 1, as: .gif)))
        XCTAssertEqual(img.gifFrameCount, 1)
    }

    func testStillPNGReportsOne() throws {
        let img = try XCTUnwrap(NSImage(data: makeImage(frames: 1, as: .png)))
        XCTAssertEqual(img.gifFrameCount, 1)
    }

    // A tiny solid-colour image encoded with `frames` frames, via ImageIO —
    // the same decoder family NSImage(data:) reads back through.
    private func makeImage(frames: Int, as type: UTType) throws -> Data {
        let data = NSMutableData()
        let dest = try XCTUnwrap(CGImageDestinationCreateWithData(
            data, type.identifier as CFString, frames, nil))
        let frameProps = [kCGImagePropertyGIFDictionary:
                            [kCGImagePropertyGIFDelayTime: 0.1]] as CFDictionary
        for i in 0..<frames {
            let shade = CGFloat(i) / CGFloat(max(frames - 1, 1))
            let ctx = try XCTUnwrap(CGContext(
                data: nil, width: 4, height: 4, bitsPerComponent: 8, bytesPerRow: 0,
                space: CGColorSpaceCreateDeviceRGB(),
                bitmapInfo: CGImageAlphaInfo.premultipliedLast.rawValue))
            ctx.setFillColor(CGColor(red: shade, green: 0, blue: 1 - shade, alpha: 1))
            ctx.fill(CGRect(x: 0, y: 0, width: 4, height: 4))
            CGImageDestinationAddImage(dest, try XCTUnwrap(ctx.makeImage()), frameProps)
        }
        XCTAssertTrue(CGImageDestinationFinalize(dest))
        return data as Data
    }
}
#endif