import Foundation
import SwiftUI
import Testing
import UIKit

@testable import Oppi

/// Tests that FlatSegment.build uses UIKit foreground colors so
/// normalizedAttributedText finds them, and the streaming -> finished
/// transition preserves colors.
@Suite("Stream finish formatting preservation")
@MainActor
struct StreamFinishFormattingTests {

    let darkPalette = ThemeID.dark.palette

    @Test func paragraphUsesUIKitForegroundColor() {
        let blocks: [MarkdownBlock] = [.paragraph([.text("hello")])]
        let segments = FlatSegment.build(from: blocks)
        guard case .text(let attributed) = segments[0] else {
            Issue.record("Expected .text segment"); return
        }
        let ns = NSAttributedString(attributed)
        var found = false
        ns.enumerateAttribute(.foregroundColor, in: NSRange(location: 0, length: ns.length)) { value, _, _ in
            if value is UIColor { found = true }
        }
        #expect(found, "Paragraph should produce UIKit foregroundColor")
    }

    @Test func inlineCodeUsesUIKitColor() {
        let blocks: [MarkdownBlock] = [.paragraph([.text("Use "), .code("foo()"), .text(" here")])]
        let segments = FlatSegment.build(from: blocks)
        guard case .text(let attributed) = segments[0] else {
            Issue.record("Expected .text segment"); return
        }
        let ns = NSAttributedString(attributed)
        let codeRange = (ns.string as NSString).range(of: "foo()")
        #expect(codeRange.location != NSNotFound)

        let color = ns.attribute(.foregroundColor, at: codeRange.location, effectiveRange: nil) as? UIColor
        #expect(color != nil, "Inline code should have UIColor")

        let baseFG = UIColor(darkPalette.fg)
        if let color {
            var r1: CGFloat = 0, g1: CGFloat = 0, b1: CGFloat = 0, a1: CGFloat = 0
            var r2: CGFloat = 0, g2: CGFloat = 0, b2: CGFloat = 0, a2: CGFloat = 0
            color.getRed(&r1, green: &g1, blue: &b1, alpha: &a1)
            baseFG.getRed(&r2, green: &g2, blue: &b2, alpha: &a2)
            let matches = abs(r1 - r2) < 0.02 && abs(g1 - g2) < 0.02 && abs(b1 - b2) < 0.02
            #expect(!matches, "Code color should differ from base fg")
        }
    }

    @Test func applierPreservesColorsAfterStreamFinish() {
        let stackView = UIStackView()
        stackView.axis = .vertical
        let applier = AssistantMarkdownSegmentApplier(
            stackView: stackView,
            textViewDelegate: NoOpTextViewDelegate()
        )

        let markdown = "Use `foo()` for results"
        let blocks = parseCommonMark(markdown)
        let segments = FlatSegment.build(from: blocks, themeID: .dark)

        applier.apply(segments: segments, config: .make(content: markdown, isStreaming: true, themeID: .dark))
        applier.apply(segments: segments, config: .make(content: markdown, isStreaming: false, themeID: .dark))

        guard let attrText = findTextViews(in: stackView).first?.attributedText else {
            Issue.record("No attributed text after finish"); return
        }

        let baseFG = UIColor(darkPalette.fg)
        let codeRange = (attrText.string as NSString).range(of: "foo()")
        guard codeRange.location != NSNotFound else {
            Issue.record("foo() not found"); return
        }

        let codeColor = attrText.attribute(.foregroundColor, at: codeRange.location, effectiveRange: nil) as? UIColor
        #expect(codeColor != nil, "Code should have UIColor after stream finish")
        if let codeColor {
            var r1: CGFloat = 0, g1: CGFloat = 0, b1: CGFloat = 0, a1: CGFloat = 0
            var r2: CGFloat = 0, g2: CGFloat = 0, b2: CGFloat = 0, a2: CGFloat = 0
            codeColor.getRed(&r1, green: &g1, blue: &b1, alpha: &a1)
            baseFG.getRed(&r2, green: &g2, blue: &b2, alpha: &a2)
            let matches = abs(r1 - r2) < 0.02 && abs(g1 - g2) < 0.02 && abs(b1 - b2) < 0.02
            #expect(!matches, "Code color should differ from base fg after stream finish")
        }
    }

    private func findTextViews(in view: UIView) -> [UITextView] {
        var result: [UITextView] = []
        for subview in view.subviews {
            if let tv = subview as? UITextView { result.append(tv) }
            result.append(contentsOf: findTextViews(in: subview))
        }
        return result
    }
}

private final class NoOpTextViewDelegate: NSObject, UITextViewDelegate {}