/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

import {
  decodeDurableToolResultProjection,
  DURABLE_TOOL_RESULT_PROJECTION_FAILURE,
  DURABLE_TOOL_RESULT_PROJECTION_MAX_JSON_DEPTH,
  DURABLE_TOOL_RESULT_PROJECTION_MAX_JSON_NODES,
  DURABLE_TOOL_RESULT_PROJECTION_MAX_PARTS,
  DURABLE_TOOL_RESULT_PROJECTION_VERSION,
  type DurableProjectionArtifactRef,
  type DurableProjectionJson,
  type DurableToolResultProjection,
  type DurableToolResultProjectionPart,
} from '@maka/core/durable-tool-result-projection';
import { MAX_READ_IMAGE_BYTES } from '@maka/core/attachments';
import {
  isCanonicalArtifactEntityId,
  normalizeArtifactImagePreviewMime,
} from '@maka/core/artifacts';
import { isCanonicalStorageRef } from '@maka/core/events';
import type { ToolResultContent } from '@maka/core/events';
import type { RuntimeEventFunctionResponseContent } from '@maka/core/runtime-event';
import { decodeCanonicalShellToolResultContent } from '@maka/core/shell-run-result';
import { markPersisted } from '@maka/core/persisted-value';
import { decodePersistedToolResultContent } from '@maka/core/tool-result-record-schema';

import type { ToolResultOutput } from './model-protocol.js';
import { toolResultOutput } from './tool-result-output.js';
import { withToolResultArchiveResourceRef } from './tool-result-archive.js';
import { projectBashToolResultForModel } from './bash-model-output.js';
import { projectFileWriteToolResultForModel } from './file-tool-model-output.js';

const OMITTED_BINARY_TEXT =
  '[Binary tool output omitted from the durable model projection; repeat the tool call if it is still needed.]';

/**
 * The only new-write codec from Runtime's tool-output contract into the
 * provider-neutral durable projection protocol. It is total by construction:
 * invalid, unsafe, or oversized output becomes one stable failure sentinel.
 */
export function encodeDurableToolResultOutput(
  output: ToolResultOutput,
  sessionId: string,
): DurableToolResultProjection {
  try {
    const projection = encodeOutput(output, sessionId);
    return decodeDurableToolResultProjection(projection);
  } catch {
    return DURABLE_TOOL_RESULT_PROJECTION_FAILURE;
  }
}

interface DurableProjectionArtifactPlan {
  ref: Extract<DurableProjectionArtifactRef, { kind: 'session_file' }>;
  persist(): Promise<void>;
  /** Undo a publication whose projection is not going to be admitted. */
  retract?(): Promise<void>;
}

type DurableProjectionArtifactPlanner = (input: {
  bytes: Uint8Array;
  mediaType: string;
}) => DurableProjectionArtifactPlan;

export function encodeDurableToolResultOutputWithArtifacts(
  output: ToolResultOutput,
  sessionId: string,
  planArtifact: DurableProjectionArtifactPlanner | undefined,
): DurableToolResultProjection | PromiseLike<DurableToolResultProjection> {
  if (!planArtifact || output.type !== 'content' || !hasInlineImage(output)) {
    return encodeDurableToolResultOutput(output, sessionId);
  }
  return (async () => {
    const publishedPlans: DurableProjectionArtifactPlan[] = [];
    try {
      const prepared = prepareContentProjection(output, sessionId, planArtifact);
      const persisted = new Set<string>();
      for (const artifact of prepared.artifacts) {
        if (persisted.has(artifact.ref.relativePath)) continue;
        await artifact.persist();
        persisted.add(artifact.ref.relativePath);
        publishedPlans.push(artifact);
      }
      return prepared.projection;
    } catch {
      // Publication is all-or-nothing: a projection this codec refuses must not
      // leave images behind that no durable record will ever reference (#4283).
      // Retraction is best effort — a failed retraction only delays reclamation.
      for (const artifact of publishedPlans) {
        await artifact.retract?.().catch(() => undefined);
      }
      return DURABLE_TOOL_RESULT_PROJECTION_FAILURE;
    }
  })();
}

export function encodeDefaultDurableToolResultOutput(
  result: unknown,
  sessionId: string,
): DurableToolResultProjection {
  const image = sessionImageResult(result, sessionId);
  if (image) {
    try {
      const mediaType = normalizeArtifactImagePreviewMime(image.mimeType);
      if (!mediaType) throw new Error('Image has an unsafe media type');
      return decodeDurableToolResultProjection({
        version: DURABLE_TOOL_RESULT_PROJECTION_VERSION,
        kind: 'content',
        parts: [{ kind: 'artifact', mediaType, ref: image.ref }],
      });
    } catch {
      return DURABLE_TOOL_RESULT_PROJECTION_FAILURE;
    }
  }
  return encodeDurableToolResultOutput(
    typeof result === 'string'
      ? { type: 'text', value: result }
      : { type: 'json', value: result as never },
    sessionId,
  );
}

export function durableProjectionToToolResultOutput(
  projection: DurableToolResultProjection,
): ToolResultOutput {
  switch (projection.kind) {
    case 'text':
      return projection.isError
        ? { type: 'error-text', value: projection.text }
        : { type: 'text', value: projection.text };
    case 'json':
      return projection.isError
        ? { type: 'error-json', value: projection.value }
        : { type: 'json', value: projection.value };
    case 'content':
      return {
        type: 'content',
        value: projection.parts.map((part) =>
          part.kind === 'text'
            ? { type: 'text' as const, text: part.text }
            : {
                type: 'text' as const,
                text: `[Artifact ${JSON.stringify(
                  part.ref.kind === 'session_context' ? part.ref.refId : part.ref.relativePath,
                )} (${part.mediaType}) is stored in this Session.]`,
              },
        ),
      };
    case 'execution_denied':
      return {
        type: 'execution-denied',
        ...(projection.reason !== undefined ? { reason: projection.reason } : {}),
      };
    case 'failure':
      return { type: 'error-text', value: projection.message };
  }
}

/**
 * The one pure decision of WHICH source a replayed Tool Result materializes
 * from: a durable projection wins, and only a response that has none (legacy
 * or provider-native) falls back to its raw output. Replay, summarization, and
 * provider-native compaction share it so no second path can re-read what the
 * projection removed. The image-materializing replay path in the ai-sdk
 * backend applies the same choice under a request budget.
 */
export function effectiveReplayToolResultOutput(item: {
  modelProjection?: DurableToolResultProjection;
  output: unknown;
  isError: boolean;
}): ToolResultOutput {
  return item.modelProjection
    ? durableProjectionToToolResultOutput(item.modelProjection)
    : toolResultOutput(item.output, item.isError);
}

export function rewriteDurableToolResultProjectionArtifactRefs(
  projection: DurableToolResultProjection,
  rewrite: (ref: DurableProjectionArtifactRef) => DurableProjectionArtifactRef,
): DurableToolResultProjection {
  if (projection.kind !== 'content') return projection;
  return {
    ...projection,
    parts: projection.parts.map((part) =>
      part.kind === 'artifact' ? { ...part, ref: rewrite(part.ref) } : part,
    ),
  };
}

type EffectiveToolResultProjection =
  | {
      kind: 'projection';
      projection: DurableToolResultProjection;
      legacyOutput: unknown;
    }
  | { kind: 'provider_native'; output: unknown }
  | { kind: 'legacy_output'; output: unknown }
  | { kind: 'invalid_legacy'; message: string };

/** The single compatibility boundary for both current and legacy response events. */
export function decodeEffectiveToolResultProjection(
  content: RuntimeEventFunctionResponseContent,
  sessionId: string,
): EffectiveToolResultProjection {
  if (content.providerExecuted && content.providerOutput !== undefined) {
    return { kind: 'provider_native', output: content.providerOutput };
  }
  if (content.modelProjection !== undefined) {
    try {
      return {
        kind: 'projection',
        projection: decodeDurableToolResultProjection(content.modelProjection),
        legacyOutput: content.result,
      };
    } catch {
      return {
        kind: 'projection',
        projection: DURABLE_TOOL_RESULT_PROJECTION_FAILURE,
        legacyOutput: content.result,
      };
    }
  }

  let output = withToolResultArchiveResourceRef(content.result);
  if (isRetiredExploreAgentResult(output)) {
    try {
      output = decodePersistedToolResultContent(markPersisted<ToolResultContent>(output));
    } catch {
      return {
        kind: 'invalid_legacy',
        message: 'function_response contains an invalid retired tool result',
      };
    }
  }
  const shellResult = decodeCanonicalShellToolResultContent(output);
  if (shellResult.state === 'invalid') {
    return {
      kind: 'invalid_legacy',
      message: 'function_response contains an invalid shell tool result',
    };
  }
  if (shellResult.state === 'valid') output = shellResult.content;
  output =
    content.name === 'Bash'
      ? projectBashToolResultForModel(output)
      : projectFileWriteToolResultForModel(content.name, output);
  const projection =
    content.isError === true
      ? encodeDurableToolResultOutput(compatibilityErrorOutput(output), sessionId)
      : encodeDefaultDurableToolResultOutput(output, sessionId);
  if (projection.kind === 'failure' && isLegacyPathImageResult(output, sessionId)) {
    return { kind: 'legacy_output', output };
  }
  return {
    kind: 'projection',
    projection,
    legacyOutput: output,
  };
}

function compatibilityErrorOutput(output: unknown): ToolResultOutput {
  return output !== null &&
    typeof output === 'object' &&
    !Array.isArray(output) &&
    (output as { kind?: unknown }).kind === 'text' &&
    typeof (output as { text?: unknown }).text === 'string'
    ? { type: 'error-text', value: new Error((output as { text: string }).text).toString() }
    : toolResultOutput(output, true);
}

export function compatibilityToolResultProjection(
  content: RuntimeEventFunctionResponseContent,
  sessionId: string,
): DurableToolResultProjection | undefined {
  const effective = decodeEffectiveToolResultProjection(content, sessionId);
  if (effective.kind === 'provider_native') return undefined;
  if (effective.kind === 'legacy_output') return DURABLE_TOOL_RESULT_PROJECTION_FAILURE;
  return effective.kind === 'projection'
    ? effective.projection
    : DURABLE_TOOL_RESULT_PROJECTION_FAILURE;
}

function encodeOutput(output: ToolResultOutput, sessionId: string): DurableToolResultProjection {
  switch (output.type) {
    case 'text':
    case 'error-text':
      return {
        version: DURABLE_TOOL_RESULT_PROJECTION_VERSION,
        kind: 'text',
        text: output.value,
        ...(output.type === 'error-text' ? { isError: true as const } : {}),
      };
    case 'json':
    case 'error-json':
      return {
        version: DURABLE_TOOL_RESULT_PROJECTION_VERSION,
        kind: 'json',
        value: sanitizeJson(output.value),
        ...(output.type === 'error-json' ? { isError: true as const } : {}),
      };
    case 'execution-denied':
      return {
        version: DURABLE_TOOL_RESULT_PROJECTION_VERSION,
        kind: 'execution_denied',
        ...(output.reason !== undefined ? { reason: output.reason } : {}),
      };
    case 'content': {
      return prepareContentProjection(output, sessionId).projection;
    }
  }
}

function prepareContentProjection(
  output: Extract<ToolResultOutput, { type: 'content' }>,
  sessionId: string,
  planArtifact?: DurableProjectionArtifactPlanner,
): {
  projection: DurableToolResultProjection;
  artifacts: DurableProjectionArtifactPlan[];
} {
  if (output.value.length > DURABLE_TOOL_RESULT_PROJECTION_MAX_PARTS) {
    throw new Error('Tool Result content exceeds the durable part limit');
  }
  const parts: DurableToolResultProjectionPart[] = [];
  const artifacts: DurableProjectionArtifactPlan[] = [];
  for (const part of output.value) {
    if (part.type === 'text') {
      parts.push({ kind: 'text', text: part.text });
      continue;
    }
    if (part.type !== 'file') continue;
    const ref = readSessionArtifactRef(part, sessionId);
    if (ref) {
      const mediaType = normalizeArtifactImagePreviewMime(part.mediaType);
      if (!mediaType) throw new Error('Artifact has an unsafe media type');
      parts.push({ kind: 'artifact', mediaType, ref });
      continue;
    }
    if (
      planArtifact &&
      part.data.type === 'data' &&
      part.mediaType.toLowerCase().startsWith('image/')
    ) {
      const mediaType = normalizeArtifactImagePreviewMime(part.mediaType);
      if (!mediaType) throw new Error('Inline image has an unsafe media type');
      const artifact = planArtifact({
        bytes: decodeBoundedImageData(part.data.data),
        mediaType,
      });
      artifacts.push(artifact);
      parts.push({ kind: 'artifact', mediaType, ref: artifact.ref });
      continue;
    }
    parts.push({ kind: 'text', text: OMITTED_BINARY_TEXT });
  }
  if (parts.length === 0) parts.push({ kind: 'text', text: 'Tool completed with no content.' });
  return {
    projection: decodeDurableToolResultProjection({
      version: DURABLE_TOOL_RESULT_PROJECTION_VERSION,
      kind: 'content',
      parts,
    }),
    artifacts,
  };
}

function readSessionArtifactRef(
  part: Extract<ToolResultOutput, { type: 'content' }>['value'][number],
  sessionId: string,
) {
  if (part.type !== 'file') return undefined;
  const data = part.data as unknown;
  if (!data || typeof data !== 'object' || Array.isArray(data)) return undefined;
  const ref = (data as { ref?: unknown }).ref;
  return isCanonicalStorageRef(ref) &&
    (ref.kind === 'session_context' || ref.kind === 'session_file') &&
    ref.sessionId === sessionId
    ? ref
    : undefined;
}

function hasInlineImage(output: Extract<ToolResultOutput, { type: 'content' }>): boolean {
  return output.value.some(
    (part) =>
      part.type === 'file' &&
      part.data.type === 'data' &&
      part.mediaType.toLowerCase().startsWith('image/'),
  );
}

function decodeBoundedImageData(data: unknown): Uint8Array {
  let bytes: Uint8Array;
  if (typeof data === 'string') {
    if (data.length > Math.ceil((MAX_READ_IMAGE_BYTES * 4) / 3) + 4) {
      throw new Error('Inline image exceeds the artifact byte limit');
    }
    const decoded = Buffer.from(data, 'base64');
    if (decoded.toString('base64') !== data)
      throw new Error('Inline image is not canonical base64');
    bytes = decoded;
  } else if (data instanceof ArrayBuffer) {
    if (data.byteLength > MAX_READ_IMAGE_BYTES) {
      throw new Error('Inline image exceeds the artifact byte limit');
    }
    bytes = new Uint8Array(data.slice(0));
  } else if (ArrayBuffer.isView(data)) {
    if (data.byteLength > MAX_READ_IMAGE_BYTES) {
      throw new Error('Inline image exceeds the artifact byte limit');
    }
    bytes = new Uint8Array(data.buffer, data.byteOffset, data.byteLength).slice();
  } else {
    throw new Error('Inline image data is not representable');
  }
  if (bytes.byteLength > MAX_READ_IMAGE_BYTES) {
    throw new Error('Inline image exceeds the artifact byte limit');
  }
  return bytes;
}

function sessionImageResult(result: unknown, sessionId: string) {
  if (!result || typeof result !== 'object' || Array.isArray(result)) return undefined;
  const image = result as { kind?: unknown; mimeType?: unknown; ref?: unknown };
  return image.kind === 'image' &&
    typeof image.mimeType === 'string' &&
    image.mimeType.length > 0 &&
    isCanonicalStorageRef(image.ref) &&
    (image.ref.kind === 'session_context' || image.ref.kind === 'session_file') &&
    image.ref.sessionId === sessionId
    ? { mimeType: image.mimeType, ref: image.ref }
    : undefined;
}

function isLegacyPathImageResult(result: unknown, sessionId: string): boolean {
  const image = sessionImageResult(result, sessionId);
  return image?.ref.kind === 'session_file' && !isCanonicalArtifactEntityId(image.ref.relativePath);
}

function sanitizeJson(value: unknown): DurableProjectionJson {
  const state = { nodes: 0 };
  return sanitizeJsonValue(value, state, 0);
}

function sanitizeJsonValue(
  value: unknown,
  state: { nodes: number },
  depth: number,
): DurableProjectionJson {
  state.nodes += 1;
  if (
    state.nodes > DURABLE_TOOL_RESULT_PROJECTION_MAX_JSON_NODES ||
    depth > DURABLE_TOOL_RESULT_PROJECTION_MAX_JSON_DEPTH
  ) {
    throw new Error('JSON exceeds limit');
  }
  if (value === null) return null;
  if (typeof value === 'string') return value;
  if (typeof value === 'boolean') return value;
  if (typeof value === 'number' && Number.isFinite(value)) return value;
  if (Array.isArray(value)) {
    return value.map((item) => sanitizeJsonValue(item, state, depth + 1));
  }
  if (!value || typeof value !== 'object') throw new Error('JSON is not representable');
  const prototype = Object.getPrototypeOf(value);
  if (prototype !== Object.prototype && prototype !== null) {
    throw new Error('JSON contains an opaque object');
  }
  if (typeof (value as { toJSON?: unknown }).toJSON === 'function') {
    throw new Error('JSON contains an opaque serializer');
  }
  const result: Record<string, DurableProjectionJson> = {};
  for (const [key, item] of Object.entries(value)) {
    Object.defineProperty(result, key, {
      enumerable: true,
      configurable: true,
      writable: true,
      value: sanitizeJsonValue(item, state, depth + 1),
    });
  }
  return result;
}

function isRetiredExploreAgentResult(value: unknown): boolean {
  return (
    value !== null &&
    typeof value === 'object' &&
    !Array.isArray(value) &&
    (value as { kind?: unknown }).kind === 'explore_agent'
  );
}