import { randomUUID } from "node:crypto";
import type { UIMessageChunk } from "ai";
import { z } from "zod";
import { agentTriggerContextSchema } from "../routes/agentTrigger.js";

const text = z.string().min(1).max(10000);
const inputMessage = z.object({
  type: z.literal("message").optional(), role: z.literal("user"),
  content: z.union([text, z.array(z.object({ type: z.literal("input_text"), text }).strict()).min(1).max(20)]),
}).strict();

// A Responses text-generation surface backed by the owned OpenCode session.
// Unsupported OpenAI options fail validation instead of being silently ignored.
export const responseRequestSchema = z.object({
  input: z.union([text, z.array(inputMessage).min(1).max(20)]),
  model: z.string().min(1).optional(),
  stream: z.boolean().default(false),
  conversation: z.union([z.string().min(1).max(128), z.object({ id: z.string().min(1).max(128) }).strict()]).optional(),
  metadata: z.record(z.string().max(64), z.string().max(512)).refine((value) => Object.keys(value).length <= 16).optional(),
  tjwater: z.object({
    topic_id: z.string().uuid().optional(),
    client_message_id: z.string().min(1).max(128).optional(),
    delivery: z.enum(["steer", "queue"]).optional(),
    input_id: z.string().regex(/^msg_[a-f0-9]{32}$/).optional(),
    interaction_id: z.string().min(1).max(128).optional(),
    approval_mode: z.enum(["request", "always"]).default("request"),
    capabilities: z.array(z.string().max(64)).max(20).default([]),
    trigger_context: agentTriggerContextSchema.optional(),
    task_context: z.object({
      report_revision: z.number().int().positive().optional(),
      evidence_id: z.string().min(1).max(128).optional(), gap_id: z.string().min(1).max(128).optional(),
    }).strict().optional(),
  }).strict().default({}),
}).strict();

export function responsePrompt(input: z.infer<typeof responseRequestSchema>["input"]) {
  return typeof input === "string" ? input : input.map((message) => typeof message.content === "string"
    ? message.content : message.content.map((part) => part.text).join("\n")).join("\n\n");
}

type OutputText = { type: "output_text"; text: string; annotations: unknown[]; logprobs: unknown[] };
type OutputMessage = { id: string; type: "message"; status: "in_progress" | "completed" | "incomplete"; role: "assistant"; content: OutputText[] };
export type ResponseObject = {
  id: string; object: "response"; created_at: number; completed_at: number | null;
  status: "in_progress" | "completed" | "failed" | "incomplete"; model: string;
  conversation: { id: string }; output: OutputMessage[]; usage: null;
  error: { code: string; message: string } | null; incomplete_details: { reason: string } | null;
  metadata: Record<string, string>;
};
export type ResponseEvent = Record<string, unknown> & { type: string; sequence_number: number };

export function createResponsesProjection(options: {
  model: string; conversationId: string; metadata?: Record<string, string>;
  emit: (event: ResponseEvent) => void;
}) {
  const response: ResponseObject = {
    id: `resp_${randomUUID().replaceAll("-", "")}`, object: "response", created_at: Math.floor(Date.now() / 1000),
    completed_at: null, status: "in_progress", model: options.model, conversation: { id: options.conversationId },
    output: [], usage: null, error: null, incomplete_details: null, metadata: options.metadata ?? {},
  };
  let sequence = 0;
  let started = false;
  const textIndices = new Map<string, number>();
  const closedText = new Set<string>();
  const emit = (type: string, value: Record<string, unknown>) => options.emit({ type, sequence_number: sequence++, ...structuredClone(value) });
  const begin = () => {
    if (started) return;
    started = true;
    emit("response.created", { response });
    emit("response.in_progress", { response });
  };
  const message = (id?: string) => {
    if (!response.output.length) {
      response.output.push({ id: id ?? `msg_${randomUUID().replaceAll("-", "")}`, type: "message", status: "in_progress", role: "assistant", content: [] });
      emit("response.output_item.added", { output_index: 0, item: response.output[0] });
    }
    return response.output[0]!;
  };
  const openText = (id: string) => {
    const item = message();
    if (!textIndices.has(id)) {
      const index = item.content.length;
      textIndices.set(id, index);
      item.content.push({ type: "output_text", text: "", annotations: [], logprobs: [] });
      emit("response.content_part.added", { item_id: item.id, output_index: 0, content_index: index, part: item.content[index] });
    }
    return { item, index: textIndices.get(id)! };
  };
  const endText = (id: string) => {
    if (!textIndices.has(id) || closedText.has(id)) return;
    const { item, index } = openText(id);
    closedText.add(id);
    emit("response.output_text.done", { item_id: item.id, output_index: 0, content_index: index, text: item.content[index]!.text, logprobs: [] });
    emit("response.content_part.done", { item_id: item.id, output_index: 0, content_index: index, part: item.content[index] });
  };
  const finish = (reason: "completed" | "failed" | "cancelled" = "completed") => {
    if (response.status !== "in_progress") return;
    begin();
    for (const id of textIndices.keys()) endText(id);
    for (const item of response.output) {
      item.status = reason === "completed" ? "completed" : "incomplete";
      emit("response.output_item.done", { output_index: 0, item });
    }
    response.status = reason === "cancelled" ? "incomplete" : reason;
    if (reason === "completed") response.completed_at = Math.floor(Date.now() / 1000);
    emit(`response.${response.status}`, { response });
  };
  return {
    response, begin, finish,
    write(chunk: UIMessageChunk) {
      if (response.status !== "in_progress") return;
      begin();
      if (chunk.type === "start") message(chunk.messageId);
      else if (chunk.type === "text-start") openText(chunk.id);
      else if (chunk.type === "text-delta") {
        const { item, index } = openText(chunk.id);
        item.content[index]!.text += chunk.delta;
        emit("response.output_text.delta", { item_id: item.id, output_index: 0, content_index: index, delta: chunk.delta, logprobs: [] });
      } else if (chunk.type === "text-end") endText(chunk.id);
      else if (chunk.type === "error") response.error = { code: "agent_execution_error", message: chunk.errorText };
      else if (chunk.type.startsWith("data-")) {
        const data = chunk as { type: string; data: unknown; id?: string; transient?: boolean };
        emit(`tjwater.${chunk.type.slice(5)}`, { response_id: response.id, data: data.data,
          ...(data.id ? { id: data.id } : {}), ...(data.transient ? { transient: true } : {}) });
      }
      // Finalization belongs to the route, after task completion and persistence.
    },
  };
}