//
// MessageFormattingEngineTests.swift
// bitchatTests
//
// Tests for MessageFormattingEngine regex patterns and utility functions.
// This is free and unencumbered software released into the public domain.
//

import Testing
import Foundation
import SwiftUI
import BitFoundation
@testable import bitchat

struct MessageFormattingEngineTests {
    // MARK: - Formatting Behavior Tests

    @MainActor
    @Test func formatMessage_regularMessageFormatsHeaderContentAndTimestamp() {
        let senderPeerID = PeerID(str: "abcdef1234567890")
        let context = MockMessageFormattingContext(
            nickname: "carol",
            peerURLs: [senderPeerID: URL(string: "https://example.com/peers/alice")!]
        )
        let message = BitchatMessage(
            id: "message-1",
            sender: "alice#a1b2",
            content: "hello #mesh https://example.com",
            timestamp: Date(timeIntervalSince1970: 1_700_000_000),
            isRelay: false,
            senderPeerID: senderPeerID
        )

        let formatted = MessageFormattingEngine.formatMessage(message, context: context, colorScheme: .light)

        #expect(String(formatted.characters) == "<@alice#a1b2> hello #mesh https://example.com [\(message.formattedTimestamp)]")
        #expect(message.getCachedFormattedText(isDark: false, isSelf: false) != nil)
    }

    @MainActor
    @Test func formatMessage_systemMessageUsesSystemLayout() {
        let context = MockMessageFormattingContext(nickname: "carol")
        let message = BitchatMessage(
            id: "system-1",
            sender: "system",
            content: "connected",
            timestamp: Date(timeIntervalSince1970: 1_700_000_123),
            isRelay: false
        )

        let formatted = MessageFormattingEngine.formatMessage(message, context: context, colorScheme: .dark)

        #expect(String(formatted.characters) == "* connected * [\(message.formattedTimestamp)]")
        #expect(message.getCachedFormattedText(isDark: true, isSelf: false) != nil)
    }

    @MainActor
    @Test func formatMessage_longSelfMessageFallsBackToPlainContentPath() {
        let context = MockMessageFormattingContext(
            nickname: "me",
            selfMessageIDs: ["self-1"]
        )
        let longContent = String(repeating: "a", count: 4_500)
        let message = BitchatMessage(
            id: "self-1",
            sender: "me#cafe",
            content: longContent,
            timestamp: Date(timeIntervalSince1970: 1_700_000_456),
            isRelay: false
        )

        let formatted = MessageFormattingEngine.formatMessage(message, context: context, colorScheme: .light)

        #expect(String(formatted.characters) == "<@me#cafe> \(longContent) [\(message.formattedTimestamp)]")
        #expect(message.getCachedFormattedText(isDark: false, isSelf: true) != nil)
    }

    @MainActor
    @Test func formatMessage_mentionsAreRenderedThroughMentionFormatter() {
        let context = MockMessageFormattingContext(nickname: "carol")
        let message = BitchatMessage(
            id: "message-mention",
            sender: "alice",
            content: "hi @bob#a1b2",
            timestamp: Date(timeIntervalSince1970: 1_700_000_789),
            isRelay: false
        )

        let formatted = MessageFormattingEngine.formatMessage(message, context: context, colorScheme: .light)

        #expect(String(formatted.characters) == "<@alice> hi bob#a1b2 [\(message.formattedTimestamp)]")
    }

    @MainActor
    @Test func formatHeader_formatsNormalAndSystemSenders() {
        let context = MockMessageFormattingContext(nickname: "carol")
        let normalMessage = BitchatMessage(
            id: "header-1",
            sender: "alice#a1b2",
            content: "hello",
            timestamp: Date(timeIntervalSince1970: 1_700_001_000),
            isRelay: false
        )
        let systemMessage = BitchatMessage(
            id: "header-2",
            sender: "system",
            content: "notice",
            timestamp: Date(timeIntervalSince1970: 1_700_001_111),
            isRelay: false
        )

        let normalHeader = MessageFormattingEngine.formatHeader(normalMessage, context: context, colorScheme: .light)
        let systemHeader = MessageFormattingEngine.formatHeader(systemMessage, context: context, colorScheme: .dark)

        #expect(String(normalHeader.characters) == "<@alice#a1b2> ")
        #expect(String(systemHeader.characters) == "system")
    }

    // MARK: - Mention Extraction Tests

    @Test func extractMentions_singleMention() {
        let content = "Hello @alice how are you?"
        let mentions = MessageFormattingEngine.extractMentions(from: content)
        #expect(mentions == ["alice"])
    }

    @Test func extractMentions_multipleMentions() {
        let content = "@alice and @bob are chatting with @charlie"
        let mentions = MessageFormattingEngine.extractMentions(from: content)
        #expect(mentions.count == 3)
        #expect(mentions.contains("alice"))
        #expect(mentions.contains("bob"))
        #expect(mentions.contains("charlie"))
    }

    @Test func extractMentions_mentionWithSuffix() {
        let content = "Hey @alice#a1b2 check this out"
        let mentions = MessageFormattingEngine.extractMentions(from: content)
        #expect(mentions == ["alice#a1b2"])
    }

    @Test func extractMentions_noMentions() {
        let content = "Just a regular message with no mentions"
        let mentions = MessageFormattingEngine.extractMentions(from: content)
        #expect(mentions.isEmpty)
    }

    @Test func extractMentions_unicodeNickname() {
        let content = "Hello @日本語 and @émile"
        let mentions = MessageFormattingEngine.extractMentions(from: content)
        #expect(mentions.count == 2)
        #expect(mentions.contains("日本語"))
        #expect(mentions.contains("émile"))
    }

    @Test func extractMentions_mentionWithUnderscore() {
        let content = "Thanks @user_name_123"
        let mentions = MessageFormattingEngine.extractMentions(from: content)
        #expect(mentions == ["user_name_123"])
    }

    @Test func extractMentions_emailNotCaptured() {
        // Email addresses should not be captured as mentions
        let content = "Contact me at test@example.com"
        let mentions = MessageFormattingEngine.extractMentions(from: content)
        // The regex will capture "example" after @ in email - this is expected behavior
        // as the regex doesn't distinguish email addresses
        #expect(mentions.count == 1)
    }

    // MARK: - Cashu Token Detection Tests

    @Test func containsCashuToken_validTokenA() {
        let content = "Here's a token: cashuAeyJwcm9vZnMiOiJIZWxsbyBXb3JsZCEgVGhpcyBpcyBhIHRlc3QgdG9rZW4i"
        #expect(MessageFormattingEngine.containsCashuToken(content))
    }

    @Test func containsCashuToken_validTokenB() {
        let content = "Payment: cashuBeyJwcm9vZnMiOiJIZWxsbyBXb3JsZCEgVGhpcyBpcyBhIHRlc3QgdG9rZW4i"
        #expect(MessageFormattingEngine.containsCashuToken(content))
    }

    @Test func containsCashuToken_noToken() {
        let content = "Just a regular message about cashews"
        #expect(!MessageFormattingEngine.containsCashuToken(content))
    }

    @Test func containsCashuToken_tooShort() {
        let content = "Invalid: cashuAshort"
        #expect(!MessageFormattingEngine.containsCashuToken(content))
    }

    // MARK: - Regex Pattern Tests

    @Test func hashtagPattern_standaloneHashtag() {
        let content = "#bitcoin is great"
        let nsContent = content as NSString
        let range = NSRange(location: 0, length: nsContent.length)
        let matches = MessageFormattingEngine.Patterns.hashtag.matches(in: content, options: [], range: range)
        #expect(matches.count == 1)
    }

    @Test func hashtagPattern_multipleHashtags() {
        let content = "#bitcoin #lightning #nostr"
        let nsContent = content as NSString
        let range = NSRange(location: 0, length: nsContent.length)
        let matches = MessageFormattingEngine.Patterns.hashtag.matches(in: content, options: [], range: range)
        #expect(matches.count == 3)
    }

    @Test func hashtagPattern_hashInMiddleOfWord() {
        let content = "test#notahashtag"
        let nsContent = content as NSString
        let range = NSRange(location: 0, length: nsContent.length)
        let matches = MessageFormattingEngine.Patterns.hashtag.matches(in: content, options: [], range: range)
        // This will match because the regex doesn't check for word boundaries
        #expect(matches.count == 1)
    }

    @Test func bolt11Pattern_mainnet() {
        let content = "Pay this: lnbc10u1pjexampleinvoice0000000000000000000000000000000000000000000"
        let nsContent = content as NSString
        let range = NSRange(location: 0, length: nsContent.length)
        let matches = MessageFormattingEngine.Patterns.bolt11.matches(in: content, options: [], range: range)
        #expect(matches.count == 1)
    }

    @Test func bolt11Pattern_testnet() {
        let content = "Test: lntb10u1pjexampleinvoice0000000000000000000000000000000000000000000"
        let nsContent = content as NSString
        let range = NSRange(location: 0, length: nsContent.length)
        let matches = MessageFormattingEngine.Patterns.bolt11.matches(in: content, options: [], range: range)
        #expect(matches.count == 1)
    }

    @Test func lnurlPattern_valid() {
        let content = "LNURL: lnurl1dp68gurn8ghj7um9wfmxjcm99e3k7mf0v9cxj0m385ekvcenxc6r2c35xvukxefcv5mkvv34x5ekzd3ev56nyd3hxqurzepexejxxepnxscrvwfnv9nxzcn9xq6xyefhvgcxxcmyxymnserx"
        let nsContent = content as NSString
        let range = NSRange(location: 0, length: nsContent.length)
        let matches = MessageFormattingEngine.Patterns.lnurl.matches(in: content, options: [], range: range)
        #expect(matches.count == 1)
    }

    @Test func lightningSchemePattern_valid() {
        let content = "Click: lightning:lnbc10u1example"
        let nsContent = content as NSString
        let range = NSRange(location: 0, length: nsContent.length)
        let matches = MessageFormattingEngine.Patterns.lightningScheme.matches(in: content, options: [], range: range)
        #expect(matches.count == 1)
    }

    @Test func cashuPattern_valid() {
        let content = "Token: cashuAeyJwcm9vZnMiOlt7ImlkIjoiMDAwMDAwMDAwMDAwMDAwMCJ9XX0="
        let nsContent = content as NSString
        let range = NSRange(location: 0, length: nsContent.length)
        let matches = MessageFormattingEngine.Patterns.cashu.matches(in: content, options: [], range: range)
        #expect(matches.count == 1)
    }

    // MARK: - URL Detection Tests

    @Test func linkDetector_httpURL() {
        let content = "Check out http://example.com"
        let nsContent = content as NSString
        let range = NSRange(location: 0, length: nsContent.length)
        let matches = MessageFormattingEngine.Patterns.linkDetector?.matches(in: content, options: [], range: range) ?? []
        #expect(matches.count == 1)
    }

    @Test func linkDetector_httpsURL() {
        let content = "Visit https://example.com/path?query=value"
        let nsContent = content as NSString
        let range = NSRange(location: 0, length: nsContent.length)
        let matches = MessageFormattingEngine.Patterns.linkDetector?.matches(in: content, options: [], range: range) ?? []
        #expect(matches.count == 1)
    }

    @Test func linkDetector_multipleURLs() {
        let content = "See https://a.com and http://b.com"
        let nsContent = content as NSString
        let range = NSRange(location: 0, length: nsContent.length)
        let matches = MessageFormattingEngine.Patterns.linkDetector?.matches(in: content, options: [], range: range) ?? []
        #expect(matches.count == 2)
    }

    // MARK: - String Extension Tests

    @Test func splitSuffix_withSuffix() {
        let name = "alice#a1b2"
        let (base, suffix) = name.splitSuffix()
        #expect(base == "alice")
        #expect(suffix == "#a1b2")
    }

    @Test func splitSuffix_withoutSuffix() {
        let name = "alice"
        let (base, suffix) = name.splitSuffix()
        #expect(base == "alice")
        #expect(suffix == "")
    }

    @Test func splitSuffix_withAtPrefix() {
        let name = "@alice#a1b2"
        let (base, suffix) = name.splitSuffix()
        #expect(base == "alice")
        #expect(suffix == "#a1b2")
    }

    @Test func hasVeryLongToken_noLongToken() {
        let content = "Short words only here"
        #expect(!content.hasVeryLongToken(threshold: 50))
    }

    @Test func hasVeryLongToken_withLongToken() {
        let longToken = String(repeating: "a", count: 100)
        let content = "Here is a \(longToken) token"
        #expect(content.hasVeryLongToken(threshold: 50))
    }

    @Test func hasVeryLongToken_exactThreshold() {
        let exactToken = String(repeating: "a", count: 50)
        let content = "Token: \(exactToken)"
        // Exactly at threshold DOES trigger (uses >= comparison)
        #expect(content.hasVeryLongToken(threshold: 50))
    }

    @Test func isLongForDisplay_doesNotIgnoreCashuLinks() {
        let cashu = "cashuA" + String(repeating: "a", count: 40)
        let content = String(repeating: "a", count: TransportConfig.uiLongMessageLengthThreshold + 1) + " " + cashu

        #expect(content.extractCashuLinks().count == 1)
        #expect(content.isLongForDisplay())
    }

    @MainActor
    @Test func formatMessage_longCashuMessageFallsBackToPlainContentPath() {
        let context = MockMessageFormattingContext(nickname: "carol")
        let cashu = "cashuA" + String(repeating: "a", count: 40)
        let longContent = "hi @bob " + cashu + " " + String(repeating: "x", count: 4_100)
        let message = BitchatMessage(
            id: "long-cashu",
            sender: "alice",
            content: longContent,
            timestamp: Date(timeIntervalSince1970: 1_700_000_999),
            isRelay: false
        )

        let formatted = MessageFormattingEngine.formatMessage(message, context: context, colorScheme: .light)

        #expect(String(formatted.characters) == "<@alice> \(longContent) [\(message.formattedTimestamp)]")
    }
}

@MainActor
private final class MockMessageFormattingContext: MessageFormattingContext {
    let nickname: String
    private let selfMessageIDs: Set<String>
    private let peerURLs: [PeerID: URL]

    init(
        nickname: String,
        selfMessageIDs: Set<String> = [],
        peerURLs: [PeerID: URL] = [:]
    ) {
        self.nickname = nickname
        self.selfMessageIDs = selfMessageIDs
        self.peerURLs = peerURLs
    }

    func isSelfMessage(_ message: BitchatMessage) -> Bool {
        selfMessageIDs.contains(message.id)
    }

    func senderColor(for message: BitchatMessage, isDark: Bool) -> Color {
        .red
    }

    func peerURL(for peerID: PeerID) -> URL? {
        peerURLs[peerID]
    }
}