//
//  MetrikaCLI.swift
//  Metrika
//
//  Author:  Simon-Pierre Boucher
//  Contact: contact@spboucher.ai
//  Copyright © 2026 Simon-Pierre Boucher. All rights reserved.
//

import ArgumentParser
import Foundation
import ZQEngine

/// Companion command-line tool: runs ZQL commands or `.zyq` do-files
/// against a headless session (default subcommand), and generates the
/// documentation site (`docs`).
@main
struct MetrikaCLI: AsyncParsableCommand {
    static let configuration = CommandConfiguration(
        commandName: "metrika-cli",
        abstract: "Metrika statistical engine — command-line interface.",
        subcommands: [RunCommand.self, DocsCommand.self],
        defaultSubcommand: RunCommand.self
    )
}

/// Default behavior: execute commands, run a do-file, or start a REPL.
struct RunCommand: AsyncParsableCommand {
    static let configuration = CommandConfiguration(
        commandName: "run",
        abstract: "Execute ZQL commands or a do-file (default)."
    )

    @Option(
        name: [.short, .customLong("execute")],
        help: "Execute a ZQL command (repeatable, runs in order)."
    )
    var execute: [String] = []

    @Argument(help: "A .zyq do-file to run.")
    var doFile: String?

    mutating func run() async throws {
        let session = try ZQSession()

        if let doFile {
            let url = URL(fileURLWithPath: (doFile as NSString).expandingTildeInPath)
            let text = try String(contentsOf: url, encoding: .utf8)
            let result = try await session.executeScript(text)
            print(result.text)
            return
        }

        if !execute.isEmpty {
            for command in execute {
                let result = try await session.execute(command)
                if !result.text.isEmpty { print(result.text) }
            }
            return
        }

        // REPL
        print("Metrika — type ZQL commands, 'exit' to quit.")
        while true {
            print(". ", terminator: "")
            guard let line = readLine() else { break }
            if line == "exit" || line == "quit" { break }
            do {
                let result = try await session.execute(line)
                if !result.text.isEmpty { print(result.text) }
            } catch {
                print("error: \(error)")
            }
        }
    }
}