import type {
  Agent,
  Message,
  MessageMetadata,
  Project,
  Session,
} from '../../types/api.js';
import * as modelContext from '../model-context.js';
import { buildMessagesPayload } from './payload.js';
import { DOOM_LOOP_THRESHOLD } from './sentinels.js';
import { streamCompletion } from './stream-phase.js';
import { DB_FLUSH_INTERVAL_MS } from './types.js';
import type {
  InferenceContext,
  StreamResult,
  TurnArgs,
} from './turn.js';

// Synthetic system note appended to the cap-hit summary call. Verbatim from
// the v1.8.2 spec — do not paraphrase: the model is more reliable when the
// instruction is short, declarative, and identical across calls.
const CAP_HIT_SUMMARY_NOTE = (limit: number) =>
  `You've reached the tool budget (${limit} calls). Produce the best answer you can with what you have. Do not call more tools.`;

const DOOM_LOOP_NOTE = (name: string) =>
  `You called ${name} with the same arguments ${DOOM_LOOP_THRESHOLD} times in a row. Stop calling it. Produce the best answer you can with what you have.`;

export async function runCapHitSummary(
  ctx: InferenceContext,
  args: TurnArgs,
  session: Session,
  project: Project,
  history: Message[],
  agent: Agent | null,
  budget: number,
): Promise<void> {
  const { sessionId, chatId, assistantMessageId, signal } = args;

  const messages = await buildMessagesPayload(session, project, history, agent, ctx.log);
  messages.push({ role: 'system', content: CAP_HIT_SUMMARY_NOTE(budget) });

  const startedRow = await ctx.sql<{ started_at: string }[]>`
    UPDATE messages
    SET started_at = clock_timestamp()
    WHERE id = ${assistantMessageId}
    RETURNING started_at
  `;
  const startedAt = startedRow[0]?.started_at ?? null;

  ctx.publish(sessionId, {
    type: 'message_started',
    message_id: assistantMessageId,
    chat_id: chatId,
    role: 'assistant',
  });

  let accumulated = '';
  let pendingFlushTimer: NodeJS.Timeout | null = null;
  let flushPromise: Promise<unknown> = Promise.resolve();
  const flushNow = () => {
    if (pendingFlushTimer) {
      clearTimeout(pendingFlushTimer);
      pendingFlushTimer = null;
    }
    const snapshot = accumulated;
    flushPromise = flushPromise.then(() =>
      ctx.sql`UPDATE messages SET content = ${snapshot} WHERE id = ${assistantMessageId}`
    );
  };
  const scheduleFlush = () => {
    if (pendingFlushTimer) return;
    pendingFlushTimer = setTimeout(() => {
      pendingFlushTimer = null;
      flushNow();
    }, DB_FLUSH_INTERVAL_MS);
  };

  let summaryOk = false;
  let summarySoftCancelled = false;
  let summaryError: string | null = null;
  let result: StreamResult | null = null;
  try {
    result = await streamCompletion(
      ctx,
      session.model,
      messages,
      { tools: null, temperature: agent?.temperature },
      (delta) => {
        accumulated += delta;
        ctx.publish(sessionId, {
          type: 'delta',
          message_id: assistantMessageId,
          chat_id: chatId,
          content: delta,
        });
        scheduleFlush();
      },
      undefined,
      signal,
    );
    summaryOk = true;
  } catch (err) {
    if (err instanceof Error && err.name === 'AbortError') {
      summarySoftCancelled = true;
    } else {
      summaryError = err instanceof Error ? err.message : String(err);
    }
  } finally {
    if (pendingFlushTimer) {
      clearTimeout(pendingFlushTimer);
      pendingFlushTimer = null;
    }
    await flushPromise;
  }

  // Finalize the summary message based on the three outcomes. The sentinel
  // is inserted regardless so the user always has the Continue affordance —
  // even on a partial / failed summary the chat history shows where the
  // budget was hit.
  if (summaryOk && result) {
    // v1.11.3: see executeToolPhase for the rationale.
    const mctx = await modelContext.getModelContext(session.model);
    const nCtx = mctx?.n_ctx ?? null;
    const [updated] = await ctx.sql<
      { tokens_used: number | null; ctx_used: number | null; ctx_max: number | null; finished_at: string | null }[]
    >`
      UPDATE messages
      SET content = ${result.content},
          status = 'complete',
          tokens_used = ${result.completionTokens},
          ctx_used = ${result.promptTokens},
          ctx_max = ${nCtx},
          finished_at = clock_timestamp()
      WHERE id = ${assistantMessageId}
      RETURNING tokens_used, ctx_used, ctx_max, finished_at
    `;
    ctx.publish(sessionId, {
      type: 'message_complete',
      message_id: assistantMessageId,
      chat_id: chatId,
      tokens_used: updated?.tokens_used ?? null,
      ctx_used: updated?.ctx_used ?? null,
      ctx_max: updated?.ctx_max ?? null,
      started_at: startedAt,
      finished_at: updated?.finished_at ?? null,
      model: session.model,
    });
  } else if (summarySoftCancelled) {
    await ctx.sql`
      UPDATE messages
      SET content = ${accumulated},
          status = 'cancelled',
          finished_at = clock_timestamp()
      WHERE id = ${assistantMessageId}
    `;
    ctx.publish(sessionId, {
      type: 'message_complete',
      message_id: assistantMessageId,
      chat_id: chatId,
    });
  } else {
    const errMeta: MessageMetadata = {
      kind: 'error',
      error_reason: 'summary_after_cap_failed',
      error_text: summaryError ?? 'summary failed',
    };
    await ctx.sql`
      UPDATE messages
      SET content = ${accumulated},
          status = 'failed',
          finished_at = clock_timestamp(),
          metadata = ${ctx.sql.json(errMeta as never)}
      WHERE id = ${assistantMessageId}
    `;
    ctx.publish(sessionId, {
      type: 'error',
      message_id: assistantMessageId,
      chat_id: chatId,
      error: summaryError ?? 'summary failed',
      reason: 'summary_after_cap_failed',
    });
  }

  // Bump session/chat updated_at exactly once for this turn.
  const [sessRow] = await ctx.sql<{ project_id: string; name: string; updated_at: string }[]>`
    UPDATE sessions SET updated_at = clock_timestamp()
    WHERE id = ${sessionId}
    RETURNING project_id, name, updated_at
  `;
  ctx.publishUser({
    type: 'session_updated',
    session_id: sessionId,
    project_id: sessRow!.project_id,
    name: sessRow!.name,
    updated_at: sessRow!.updated_at,
  });

  await insertCapHitSentinel(ctx, sessionId, chatId, agent, budget);

  // Status frame fires last so the dot color reflects the terminal state.
  // Success → idle, abort → idle (user-driven stop), error → error+reason.
  if (summaryOk) {
    ctx.publishUser({ type: 'chat_status', chat_id: chatId, status: 'idle', at: new Date().toISOString() });
  } else if (summarySoftCancelled) {
    ctx.publishUser({ type: 'chat_status', chat_id: chatId, status: 'idle', at: new Date().toISOString() });
  } else {
    ctx.publishUser({
      type: 'chat_status',
      chat_id: chatId,
      status: 'error',
      at: new Date().toISOString(),
      reason: 'summary_after_cap_failed',
    });
  }

  ctx.log.info(
    { sessionId, chatId, assistantMessageId, budget, summaryOk, summaryCancelled: summarySoftCancelled },
    'inference cap-hit summary finished',
  );
}

async function insertCapHitSentinel(
  ctx: InferenceContext,
  sessionId: string,
  chatId: string,
  agent: Agent | null,
  budget: number,
): Promise<void> {
  // Hard ceiling: count prior cap_hit sentinels in this chat. After two
  // continues (sentinel count of 2), the next sentinel reports can_continue
  // false and the UI disables the Continue button.
  const priorRows = await ctx.sql<{ count: number }[]>`
    SELECT COUNT(*)::int AS count
    FROM messages
    WHERE chat_id = ${chatId}
      AND role = 'system'
      AND metadata->>'kind' = 'cap_hit'
  `;
  const priorCount = priorRows[0]?.count ?? 0;
  const canContinue = priorCount < 2;
  const metadata: MessageMetadata = {
    kind: 'cap_hit',
    used: budget,
    limit: budget,
    agent_name: agent?.name ?? null,
    can_continue: canContinue,
  };
  const content = `Reached tool budget (${budget}/${budget}). Continue to extend.`;

  const [row] = await ctx.sql<{ id: string }[]>`
    INSERT INTO messages (session_id, chat_id, role, content, status, created_at, metadata)
    VALUES (${sessionId}, ${chatId}, 'system', ${content}, 'complete', clock_timestamp(), ${ctx.sql.json(metadata as never)})
    RETURNING id
  `;

  // The sentinel content is static, but we still walk the standard frame
  // sequence (started → delta → complete) so useSessionStream's reducer
  // appends it via the same path it uses for streaming assistant messages.
  // The delta carries the full text in one chunk.
  ctx.publish(sessionId, {
    type: 'message_started',
    message_id: row!.id,
    chat_id: chatId,
    role: 'system',
  });
  ctx.publish(sessionId, {
    type: 'delta',
    message_id: row!.id,
    chat_id: chatId,
    content,
  });
  ctx.publish(sessionId, {
    type: 'message_complete',
    message_id: row!.id,
    chat_id: chatId,
    metadata,
  });
}

// v1.11.6: doom-loop wrap-up. Mirrors runCapHitSummary structurally — same
// in-flight-slot reuse, same tools-disabled streaming-summary call, same
// post-finalize sentinel insert + chat_status drop. Differences:
//   - synthetic note text comes from DOOM_LOOP_NOTE (names the looping tool)
//   - sentinel metadata is { kind: 'doom_loop', tool_name, args, threshold }
//     and has no Continue affordance (manual retry would just re-loop)
//   - chat_status error path uses reason: 'doom_loop_summary_failed'
// Kept as a clone rather than refactored into a shared helper because the
// two summary paths still differ in error reason + sentinel shape; a third
// sentinel would justify factoring out runWrapUpSummary(opts).
export async function runDoomLoopSummary(
  ctx: InferenceContext,
  args: TurnArgs,
  session: Session,
  project: Project,
  history: Message[],
  agent: Agent | null,
  loop: { name: string; args: Record<string, unknown> },
): Promise<void> {
  const { sessionId, chatId, assistantMessageId, signal } = args;

  const messages = await buildMessagesPayload(session, project, history, agent, ctx.log);
  messages.push({ role: 'system', content: DOOM_LOOP_NOTE(loop.name) });

  const startedRow = await ctx.sql<{ started_at: string }[]>`
    UPDATE messages
    SET started_at = clock_timestamp()
    WHERE id = ${assistantMessageId}
    RETURNING started_at
  `;
  const startedAt = startedRow[0]?.started_at ?? null;

  ctx.publish(sessionId, {
    type: 'message_started',
    message_id: assistantMessageId,
    chat_id: chatId,
    role: 'assistant',
  });

  let accumulated = '';
  let pendingFlushTimer: NodeJS.Timeout | null = null;
  let flushPromise: Promise<unknown> = Promise.resolve();
  const flushNow = () => {
    if (pendingFlushTimer) {
      clearTimeout(pendingFlushTimer);
      pendingFlushTimer = null;
    }
    const snapshot = accumulated;
    flushPromise = flushPromise.then(() =>
      ctx.sql`UPDATE messages SET content = ${snapshot} WHERE id = ${assistantMessageId}`
    );
  };
  const scheduleFlush = () => {
    if (pendingFlushTimer) return;
    pendingFlushTimer = setTimeout(() => {
      pendingFlushTimer = null;
      flushNow();
    }, DB_FLUSH_INTERVAL_MS);
  };

  let summaryOk = false;
  let summarySoftCancelled = false;
  let summaryError: string | null = null;
  let result: StreamResult | null = null;
  try {
    result = await streamCompletion(
      ctx,
      session.model,
      messages,
      { tools: null, temperature: agent?.temperature },
      (delta) => {
        accumulated += delta;
        ctx.publish(sessionId, {
          type: 'delta',
          message_id: assistantMessageId,
          chat_id: chatId,
          content: delta,
        });
        scheduleFlush();
      },
      undefined,
      signal,
    );
    summaryOk = true;
  } catch (err) {
    if (err instanceof Error && err.name === 'AbortError') {
      summarySoftCancelled = true;
    } else {
      summaryError = err instanceof Error ? err.message : String(err);
    }
  } finally {
    if (pendingFlushTimer) {
      clearTimeout(pendingFlushTimer);
      pendingFlushTimer = null;
    }
    await flushPromise;
  }

  if (summaryOk && result) {
    const mctx = await modelContext.getModelContext(session.model);
    const nCtx = mctx?.n_ctx ?? null;
    const [updated] = await ctx.sql<
      { tokens_used: number | null; ctx_used: number | null; ctx_max: number | null; finished_at: string | null }[]
    >`
      UPDATE messages
      SET content = ${result.content},
          status = 'complete',
          tokens_used = ${result.completionTokens},
          ctx_used = ${result.promptTokens},
          ctx_max = ${nCtx},
          finished_at = clock_timestamp()
      WHERE id = ${assistantMessageId}
      RETURNING tokens_used, ctx_used, ctx_max, finished_at
    `;
    ctx.publish(sessionId, {
      type: 'message_complete',
      message_id: assistantMessageId,
      chat_id: chatId,
      tokens_used: updated?.tokens_used ?? null,
      ctx_used: updated?.ctx_used ?? null,
      ctx_max: updated?.ctx_max ?? null,
      started_at: startedAt,
      finished_at: updated?.finished_at ?? null,
      model: session.model,
    });
  } else if (summarySoftCancelled) {
    await ctx.sql`
      UPDATE messages
      SET content = ${accumulated},
          status = 'cancelled',
          finished_at = clock_timestamp()
      WHERE id = ${assistantMessageId}
    `;
    ctx.publish(sessionId, {
      type: 'message_complete',
      message_id: assistantMessageId,
      chat_id: chatId,
    });
  } else {
    // Doom-loop summary failure reuses the existing summary_after_cap_failed
    // error reason — the ErrorReason union is shared between sentinel paths
    // and the UI surfaces a generic "summary failed" line for both. We don't
    // add a new reason code because the user-visible failure mode is the
    // same (model gave up mid-summary). Sentinel below still fires.
    const errMeta: MessageMetadata = {
      kind: 'error',
      error_reason: 'summary_after_cap_failed',
      error_text: summaryError ?? 'doom-loop summary failed',
    };
    await ctx.sql`
      UPDATE messages
      SET content = ${accumulated},
          status = 'failed',
          finished_at = clock_timestamp(),
          metadata = ${ctx.sql.json(errMeta as never)}
      WHERE id = ${assistantMessageId}
    `;
    ctx.publish(sessionId, {
      type: 'error',
      message_id: assistantMessageId,
      chat_id: chatId,
      error: summaryError ?? 'doom-loop summary failed',
      reason: 'summary_after_cap_failed',
    });
  }

  const [sessRow] = await ctx.sql<{ project_id: string; name: string; updated_at: string }[]>`
    UPDATE sessions SET updated_at = clock_timestamp()
    WHERE id = ${sessionId}
    RETURNING project_id, name, updated_at
  `;
  ctx.publishUser({
    type: 'session_updated',
    session_id: sessionId,
    project_id: sessRow!.project_id,
    name: sessRow!.name,
    updated_at: sessRow!.updated_at,
  });

  await insertDoomLoopSentinel(ctx, sessionId, chatId, loop);

  if (summaryOk || summarySoftCancelled) {
    ctx.publishUser({ type: 'chat_status', chat_id: chatId, status: 'idle', at: new Date().toISOString() });
  } else {
    ctx.publishUser({
      type: 'chat_status',
      chat_id: chatId,
      status: 'error',
      at: new Date().toISOString(),
      reason: 'summary_after_cap_failed',
    });
  }

  ctx.log.info(
    { sessionId, chatId, assistantMessageId, loopedTool: loop.name, summaryOk, summaryCancelled: summarySoftCancelled },
    'inference doom-loop summary finished',
  );
}

async function insertDoomLoopSentinel(
  ctx: InferenceContext,
  sessionId: string,
  chatId: string,
  loop: { name: string; args: Record<string, unknown> },
): Promise<void> {
  // No hard-ceiling / can-continue logic here — doom-loop is a different
  // failure mode from cap-hit. Continuing would re-trigger the loop with
  // the same tools available; the user needs to restate their question
  // or switch agents instead.
  const metadata: MessageMetadata = {
    kind: 'doom_loop',
    tool_name: loop.name,
    args: loop.args,
    threshold: DOOM_LOOP_THRESHOLD,
  };
  const content = `Detected ${DOOM_LOOP_THRESHOLD} identical calls to ${loop.name}. Stopping the tool-call loop. Produce the best answer you can with what you have.`;

  const [row] = await ctx.sql<{ id: string }[]>`
    INSERT INTO messages (session_id, chat_id, role, content, status, created_at, metadata)
    VALUES (${sessionId}, ${chatId}, 'system', ${content}, 'complete', clock_timestamp(), ${ctx.sql.json(metadata as never)})
    RETURNING id
  `;

  // Standard frame sequence — same as cap-hit sentinel — so
  // useSessionStream's reducer appends the row via the existing path.
  ctx.publish(sessionId, {
    type: 'message_started',
    message_id: row!.id,
    chat_id: chatId,
    role: 'system',
  });
  ctx.publish(sessionId, {
    type: 'delta',
    message_id: row!.id,
    chat_id: chatId,
    content,
  });
  ctx.publish(sessionId, {
    type: 'message_complete',
    message_id: row!.id,
    chat_id: chatId,
    metadata,
  });
}