//
//  ContentView.swift
//  transcriptor
//
//  Proves the capture→VAD→ASR→SSE circuit end to end from a native UI.
//  audiotee, transcriptor-ai, and qwen_asr are embedded in the app bundle
//  (see scripts/embed-binaries.sh, the "Embed audiotee, transcriptor-ai,
//  qwen_asr" Run Script build phase). The AI model is the one thing still
//  fetched at runtime (see ModelManager.swift) — deliberately, not an
//  oversight, see CLAUDE.md "Goal".
//

import SwiftUI

private enum BundledPaths {
    static var audioteeBinary: String {
        Bundle.main.url(forResource: "audiotee", withExtension: nil)!.path
    }
    static var transcriptorAiBinary: String {
        Bundle.main.url(forResource: "transcriptor-ai", withExtension: nil)!.path
    }
    static var qwenAsrBinary: String {
        Bundle.main.url(forResource: "qwen_asr", withExtension: nil)!.path
    }
    static let httpAddr = ":8420"
    static let sseURL = URL(string: "http://localhost:8420/events")!
}

struct ContentView: View {
    // Owned by AppDelegate, not created here, so it can be stopped from
    // applicationWillTerminate when the app quits — see AppDelegate.swift.
    let transcriptorProcess: TranscriptorProcess
    @State private var modelManager = ModelManager()
    // @AppStorage, not @State: without this, the picker silently reset to
    // .large on every app relaunch (its hardcoded default), discarding
    // whatever the user had picked last session — same persistence
    // treatment as transcriptSaveDirectory/glossaryFilePath below.
    // ModelChoice is RawRepresentable (String), which @AppStorage supports
    // directly, no separate string key needed.
    @AppStorage("selectedModel") private var selectedModel: ModelChoice = .large
    @State private var sseClient = SSEClient()
    @State private var errorMessage: String?
    // @AppStorage: same reasoning/bug as selectedModel above — these were
    // still @State until this fix and reset to both-on every relaunch,
    // silently discarding a "mic off" choice from a prior session. Caught
    // the same way: a relaunch-for-a-different-test lost this setting
    // mid-session and produced a confusing, uncontrolled test run.
    @AppStorage("captureSystem") private var captureSystem = true
    @AppStorage("captureMic") private var captureMic = true
    @AppStorage(TranscriptSaveLocation.defaultsKey)
    private var transcriptSaveDirectory = TranscriptSaveLocation.defaultDirectory.path
    @AppStorage(GlossaryFileLocation.defaultsKey)
    private var glossaryFilePath = GlossaryFileLocation.defaultPath.path

    private var controlsDisabled: Bool {
        transcriptorProcess.isRunning || modelManager.isDownloading
    }

    var body: some View {
        VStack(spacing: 0) {
            VStack(alignment: .leading, spacing: 8) {
                HStack {
                    Picker("Model", selection: $selectedModel) {
                        ForEach(ModelChoice.allCases) { choice in
                            Text(choice.displayName).tag(choice)
                        }
                    }
                    .frame(maxWidth: 260)
                    .disabled(controlsDisabled)

                    Text("Capture:")
                        .foregroundStyle(.secondary)
                    Toggle("System audio", isOn: $captureSystem)
                        .disabled(controlsDisabled)
                    Toggle("Microphone", isOn: $captureMic)
                        .disabled(controlsDisabled)
                }

                HStack {
                    Button(transcriptorProcess.isRunning ? "Stop" : "Start") {
                        if transcriptorProcess.isRunning {
                            stop()
                        } else {
                            Task { await start() }
                        }
                    }
                    .disabled(modelManager.isDownloading || (!captureSystem && !captureMic))

                    Text(statusText)
                        .foregroundStyle(.secondary)
                    Spacer()
                    if let errorMessage {
                        Text(errorMessage)
                            .foregroundStyle(.red)
                            .lineLimit(1)
                    }
                }
            }
            .padding()

            if modelManager.isDownloading {
                VStack(alignment: .leading, spacing: 4) {
                    Text(modelManager.statusText)
                        .font(.caption)
                        .foregroundStyle(.secondary)
                    ProgressView(value: modelManager.fileProgress)
                }
                .padding([.horizontal, .bottom])
            }

            Divider()

            ScrollViewReader { proxy in
                ScrollView {
                    LazyVStack(alignment: .leading, spacing: 10) {
                        ForEach(sseClient.messages) { message in
                            MessageBubble(message: message)
                                .id(message.id)
                        }
                    }
                    .padding()
                }
                .onChange(of: sseClient.messages.count) {
                    if let last = sseClient.messages.last {
                        withAnimation {
                            proxy.scrollTo(last.id, anchor: .bottom)
                        }
                    }
                }
            }
        }
        .frame(minWidth: 480, minHeight: 360)
    }

    private var statusText: String {
        if transcriptorProcess.isRunning { return "Running" }
        if modelManager.isDownloading { return "Downloading model…" }
        return "Stopped"
    }

    private func start() async {
        errorMessage = nil
        sseClient.clear()

        let modelDir: URL
        do {
            // No-ops immediately if already downloaded — see
            // ModelManager.isDownloaded. This is what makes "Start" a
            // single action regardless of whether the model needs
            // fetching first.
            modelDir = try await modelManager.ensureModel(selectedModel)
        } catch {
            errorMessage = "Model download failed: \(error)"
            return
        }

        let transcriptFilePath: String?
        do {
            transcriptFilePath = try makeTranscriptFilePath(startedAt: Date())
        } catch {
            errorMessage = "Couldn't prepare transcript save location: \(error)"
            return
        }

        let config = TranscriptorProcess.Config(
            binaryPath: BundledPaths.transcriptorAiBinary,
            audioteeBinaryPath: BundledPaths.audioteeBinary,
            asrBinaryPath: BundledPaths.qwenAsrBinary,
            asrModelDir: modelDir.path,
            httpAddr: BundledPaths.httpAddr,
            transcriptFilePath: transcriptFilePath,
            captureSystem: captureSystem,
            captureMic: captureMic,
            glossary: readGlossaryFile()
        )
        do {
            try transcriptorProcess.start(config)
            // transcriptor-ai's HTTP server starts early in its own
            // startup, but not instantly — give it a moment before
            // connecting rather than building retry logic for this
            // proof-of-circuit step.
            Task {
                try? await Task.sleep(for: .seconds(1))
                sseClient.connect(to: BundledPaths.sseURL)
            }
        } catch {
            errorMessage = "\(error)"
        }
    }

    private func stop() {
        transcriptorProcess.stop()
        sseClient.disconnect()
    }

    /// Builds the transcript file path for a session that started at
    /// `startedAt`, creating the save directory if it doesn't exist yet.
    /// The filename is the start timestamp, not configurable separately —
    /// per spec, only the directory is a user setting.
    private func makeTranscriptFilePath(startedAt: Date) throws -> String {
        let directory = URL(fileURLWithPath: transcriptSaveDirectory)
        try FileManager.default.createDirectory(at: directory, withIntermediateDirectories: true)

        let formatter = DateFormatter()
        formatter.dateFormat = "yyyy-MM-dd_HH-mm-ss"
        let filename = "\(formatter.string(from: startedAt)).txt"

        return directory.appendingPathComponent(filename).path
    }

    /// Reads the glossary file's content for use as qwen_asr's --prompt.
    /// Missing file or read error is not a failure — glossary is optional,
    /// so this silently returns nil rather than blocking Start.
    ///
    /// Wraps the raw comma-separated terms as "Preserve spelling: ..." —
    /// qwen_asr's own documented --prompt example format — instead of
    /// passing them as a bare list. Found via real testing: a bare list
    /// occasionally leaked verbatim into the transcript output (the model
    /// echoed the prompt instead of transcribing that segment's audio,
    /// e.g. a whole segment came back as literally the glossary terms).
    /// Framing it as an instruction rather than free-floating content is
    /// expected to reduce that risk — not proven eliminated, just
    /// following the tool's own recommended usage instead of deviating
    /// from it. The glossary *file* itself still holds only the bare
    /// terms (matches the Settings UI's help text and keeps the file
    /// simple to hand-edit) — this wrapping is applied here, not stored.
    private func readGlossaryFile() -> String? {
        guard let content = try? String(contentsOfFile: glossaryFilePath, encoding: .utf8) else {
            return nil
        }
        let trimmed = content.trimmingCharacters(in: .whitespacesAndNewlines)
        guard !trimmed.isEmpty else { return nil }
        return "Preserve spelling: \(trimmed)"
    }
}

#Preview {
    ContentView(transcriptorProcess: TranscriptorProcess())
}

/// Renders a transcript message as a chat bubble — mic ("Me") on the
/// right, system ("Them") on the left, matching the "me vs them"
/// diarization framing the two-track capture design is built around (see
/// transcriptor-ai/CLAUDE.md). Requested explicitly: the plain track-label
/// prefix wasn't distinct enough to tell the two apart at a glance.
private struct MessageBubble: View {
    let message: TranscriptMessage

    private var isMic: Bool { message.track == "mic" }

    var body: some View {
        HStack {
            if isMic { Spacer(minLength: 40) }

            VStack(alignment: isMic ? .trailing : .leading, spacing: 2) {
                Text(isMic ? "Me" : "Them")
                    .font(.caption2)
                    .foregroundStyle(.secondary)
                Text(message.text)
                    .padding(.horizontal, 12)
                    .padding(.vertical, 8)
                    .background(isMic ? Color.accentColor.opacity(0.85) : Color.secondary.opacity(0.18))
                    .foregroundStyle(isMic ? Color.white : Color.primary)
                    .clipShape(RoundedRectangle(cornerRadius: 14))
            }
            .opacity(message.isFinal ? 1 : 0.6)

            if !isMic { Spacer(minLength: 40) }
        }
    }
}