//
//  TaskTranscriptExporter.swift
//  Zyquo Agent
//
//  Author: Simon-Pierre Boucher
//  Mail: contact@spboucher.ai
//
//  Exports a task's transcript (prompts, run steps with tool calls/results,
//  final answers) as Markdown or PDF via NSSavePanel. The PDF path stays
//  deliberately simple: the Markdown text set on an off-screen NSTextView,
//  rendered with dataWithPDF (standard AppKit, no print dialog).
//

import AppKit
import Foundation
import UniformTypeIdentifiers

@MainActor
enum TaskTranscriptExporter {
    enum Format {
        case markdown
        case pdf
    }

    /// Presents the save panel and writes the transcript in the given format.
    static func presentSavePanel(for task: AgentTask, format: Format) {
        let panel = NSSavePanel()
        switch format {
        case .markdown:
            panel.allowedContentTypes = [.plainText]
            panel.nameFieldStringValue = "\(WorkspaceManager.slug(from: task.title)).md"
        case .pdf:
            panel.allowedContentTypes = [.pdf]
            panel.nameFieldStringValue = "\(WorkspaceManager.slug(from: task.title)).pdf"
        }
        let markdown = markdown(for: task)
        panel.begin { response in
            guard response == .OK, let url = panel.url else { return }
            Task { @MainActor in
                switch format {
                case .markdown:
                    try? markdown.write(to: url, atomically: true, encoding: .utf8)
                case .pdf:
                    if let data = pdfData(from: markdown, title: task.title) {
                        try? data.write(to: url, options: .atomic)
                    }
                }
            }
        }
    }

    // MARK: - Markdown

    /// The task's history (prompts, steps, answers) as Markdown.
    static func markdown(for task: AgentTask) -> String {
        var lines: [String] = ["# \(task.title)", ""]
        lines.append("Model: `\(task.modelID)` (\(task.providerID.displayName)) · Safety: \(task.safetyMode.displayName)")
        if let workspace = task.workspacePath {
            lines.append("Workspace: `\(workspace)`")
        }
        lines.append("")
        for message in task.messages {
            switch message.kind {
            case .user:
                lines.append("## 🧑 Prompt")
                lines.append(message.text)
            case .agentRun:
                lines.append("## 🤖 Run")
                for step in message.steps ?? [] {
                    lines.append("### Step \(step.index)")
                    if !step.text.isEmpty { lines.append(step.text) }
                    for invocation in step.toolInvocations {
                        lines.append("```")
                        lines.append("\(invocation.call.name): \(invocation.call.argumentsJSON)")
                        if let result = invocation.result {
                            lines.append("→ \(result.content)")
                        }
                        lines.append("```")
                    }
                }
                if !message.text.isEmpty {
                    lines.append("### Result")
                    lines.append(message.text)
                }
            }
            lines.append("")
        }
        return lines.joined(separator: "\n")
    }

    // MARK: - PDF

    /// Renders the Markdown text into PDF data via an off-screen NSTextView.
    /// Headings get a heavier system font; fenced blocks stay monospaced.
    static func pdfData(from markdown: String, title: String) -> Data? {
        let attributed = attributedTranscript(from: markdown)
        let pageWidth: CGFloat = 612 // US Letter, points
        let inset: CGFloat = 48
        let textView = NSTextView(frame: NSRect(x: 0, y: 0, width: pageWidth, height: 10))
        textView.textContainerInset = NSSize(width: inset, height: inset)
        textView.isEditable = false
        textView.textStorage?.setAttributedString(attributed)
        guard let container = textView.textContainer, let manager = textView.layoutManager else {
            return nil
        }
        manager.ensureLayout(for: container)
        let used = manager.usedRect(for: container)
        textView.frame = NSRect(x: 0, y: 0, width: pageWidth, height: used.height + inset * 2)
        return textView.dataWithPDF(inside: textView.bounds)
    }

    /// Simple line-based styling: #/##/### headings, ``` code fences, body.
    private static func attributedTranscript(from markdown: String) -> NSAttributedString {
        let result = NSMutableAttributedString()
        let bodyFont = NSFont.systemFont(ofSize: 11)
        let codeFont = NSFont.monospacedSystemFont(ofSize: 9.5, weight: .regular)
        var inCodeFence = false

        for line in markdown.components(separatedBy: "\n") {
            var font = bodyFont
            var text = line
            if line.hasPrefix("```") {
                inCodeFence.toggle()
                continue
            }
            if inCodeFence {
                font = codeFont
            } else if line.hasPrefix("### ") {
                font = NSFont.systemFont(ofSize: 12, weight: .semibold)
                text = String(line.dropFirst(4))
            } else if line.hasPrefix("## ") {
                font = NSFont.systemFont(ofSize: 14, weight: .semibold)
                text = String(line.dropFirst(3))
            } else if line.hasPrefix("# ") {
                font = NSFont.systemFont(ofSize: 18, weight: .bold)
                text = String(line.dropFirst(2))
            }
            result.append(NSAttributedString(
                string: text + "\n",
                attributes: [.font: font, .foregroundColor: NSColor.textColor]
            ))
        }
        return result
    }
}