package com.example.aiapp

import org.json.JSONObject

// The common event model, mirrored from server/src/session/driver.rs --
// the app renders purely from this stream (replayed from the transcript by
// cursor, then live), so there is no separate "load history" shape to keep
// in sync with it.

/** One transcript line: the event plus its resume cursor and time. */
data class SeqEvent(val seq: Long, val ts: Double, val event: SessionEvent)

sealed class SessionEvent {
    data class UserMessage(val text: String) : SessionEvent()
    data class AssistantText(val delta: String) : SessionEvent()
    data class ToolStart(val id: String, val tool: String, val input: String) : SessionEvent()
    data class ToolUpdate(val id: String, val output: String) : SessionEvent()
    data class ToolEnd(val id: String, val output: String) : SessionEvent()
    data class Image(val ref: String) : SessionEvent()
    data class Question(val id: String, val prompt: String, val options: List<String>) : SessionEvent()
    data class Answered(val id: String, val answer: String) : SessionEvent()
    data class Status(val state: String) : SessionEvent()
    data class UsageDelta(val tokens: Long) : SessionEvent()
    data class Error(val message: String) : SessionEvent()

    /**
     * An event type this app build doesn't know -- a newer server. Kept
     * (not thrown) so one new event kind degrades to a placeholder row
     * instead of killing the stream.
     */
    data class Unknown(val type: String) : SessionEvent()
}

fun parseSeqEvent(json: String): SeqEvent {
    val body = JSONObject(json)
    val event = when (val type = body.getString("type")) {
        "userMessage" -> SessionEvent.UserMessage(body.getString("text"))
        "assistantText" -> SessionEvent.AssistantText(body.getString("delta"))
        "toolStart" -> SessionEvent.ToolStart(
            id = body.getString("id"),
            tool = body.getString("tool"),
            // Kept as raw JSON text: the input shape is the tool's own
            // business, and the UI only ever shows it verbatim.
            input = body.get("input").toString(),
        )
        "toolUpdate" -> SessionEvent.ToolUpdate(body.getString("id"), body.getString("output"))
        "toolEnd" -> SessionEvent.ToolEnd(body.getString("id"), body.getString("output"))
        "image" -> SessionEvent.Image(body.getString("ref"))
        "question" -> SessionEvent.Question(
            id = body.getString("id"),
            prompt = body.getString("prompt"),
            options = body.getJSONArray("options").let { options ->
                (0 until options.length()).map { options.getString(it) }
            },
        )
        "answered" -> SessionEvent.Answered(body.getString("id"), body.getString("answer"))
        "status" -> SessionEvent.Status(body.getString("state"))
        "usageDelta" -> SessionEvent.UsageDelta(body.getLong("tokens"))
        "error" -> SessionEvent.Error(body.getString("message"))
        else -> SessionEvent.Unknown(type)
    }
    return SeqEvent(seq = body.getLong("seq"), ts = body.getDouble("ts"), event = event)
}