import {
  cleanSchemaForGemini,
  GEMINI_UNSUPPORTED_SCHEMA_KEYWORDS,
} from "../agents/schema/clean-for-gemini.js";
import type { ModelCompatConfig } from "../config/types.models.js";
import { applyModelCompatPatch } from "../plugins/provider-model-compat.js";
import type {
  AnyAgentTool,
  ProviderNormalizeToolSchemasContext,
  ProviderToolSchemaDiagnostic,
} from "./plugin-entry.js";

// Shared provider-tool helpers for plugin-owned schema compatibility rewrites.
export { cleanSchemaForGemini, GEMINI_UNSUPPORTED_SCHEMA_KEYWORDS };

export const XAI_TOOL_SCHEMA_PROFILE = "xai";
export const HTML_ENTITY_TOOL_CALL_ARGUMENTS_ENCODING = "html-entities";

export const XAI_UNSUPPORTED_SCHEMA_KEYWORDS = new Set([
  "minLength",
  "maxLength",
  "minItems",
  "maxItems",
  "minContains",
  "maxContains",
]);

export function stripUnsupportedSchemaKeywords(
  schema: unknown,
  unsupportedKeywords: ReadonlySet<string>,
): unknown {
  if (!schema || typeof schema !== "object") {
    return schema;
  }
  if (Array.isArray(schema)) {
    return schema.map((entry) => stripUnsupportedSchemaKeywords(entry, unsupportedKeywords));
  }
  const obj = schema as Record<string, unknown>;
  const cleaned: Record<string, unknown> = {};
  for (const [key, value] of Object.entries(obj)) {
    if (unsupportedKeywords.has(key)) {
      continue;
    }
    if (key === "properties" && value && typeof value === "object" && !Array.isArray(value)) {
      cleaned[key] = Object.fromEntries(
        Object.entries(value as Record<string, unknown>).map(([childKey, childValue]) => [
          childKey,
          stripUnsupportedSchemaKeywords(childValue, unsupportedKeywords),
        ]),
      );
      continue;
    }
    if (key === "items" && value && typeof value === "object") {
      cleaned[key] = Array.isArray(value)
        ? value.map((entry) => stripUnsupportedSchemaKeywords(entry, unsupportedKeywords))
        : stripUnsupportedSchemaKeywords(value, unsupportedKeywords);
      continue;
    }
    if ((key === "anyOf" || key === "oneOf" || key === "allOf") && Array.isArray(value)) {
      cleaned[key] = value.map((entry) =>
        stripUnsupportedSchemaKeywords(entry, unsupportedKeywords),
      );
      continue;
    }
    cleaned[key] = value;
  }
  return cleaned;
}

export function stripXaiUnsupportedKeywords(schema: unknown): unknown {
  return stripUnsupportedSchemaKeywords(schema, XAI_UNSUPPORTED_SCHEMA_KEYWORDS);
}

export function resolveXaiModelCompatPatch(): ModelCompatConfig {
  return {
    toolSchemaProfile: XAI_TOOL_SCHEMA_PROFILE,
    unsupportedToolSchemaKeywords: Array.from(XAI_UNSUPPORTED_SCHEMA_KEYWORDS),
    nativeWebSearchTool: true,
    toolCallArgumentsEncoding: HTML_ENTITY_TOOL_CALL_ARGUMENTS_ENCODING,
  };
}

export function applyXaiModelCompat<T extends { compat?: unknown }>(model: T): T {
  return applyModelCompatPatch(
    model as T & { compat?: ModelCompatConfig },
    resolveXaiModelCompatPatch(),
  ) as T;
}

export function findUnsupportedSchemaKeywords(
  schema: unknown,
  path: string,
  unsupportedKeywords: ReadonlySet<string>,
): string[] {
  if (!schema || typeof schema !== "object") {
    return [];
  }
  if (Array.isArray(schema)) {
    return schema.flatMap((item, index) =>
      findUnsupportedSchemaKeywords(item, `${path}[${index}]`, unsupportedKeywords),
    );
  }
  const record = schema as Record<string, unknown>;
  const violations: string[] = [];
  const properties =
    record.properties && typeof record.properties === "object" && !Array.isArray(record.properties)
      ? (record.properties as Record<string, unknown>)
      : undefined;
  if (properties) {
    for (const [key, value] of Object.entries(properties)) {
      violations.push(
        ...findUnsupportedSchemaKeywords(value, `${path}.properties.${key}`, unsupportedKeywords),
      );
    }
  }
  for (const [key, value] of Object.entries(record)) {
    if (key === "properties") {
      continue;
    }
    if (unsupportedKeywords.has(key)) {
      violations.push(`${path}.${key}`);
    }
    if (value && typeof value === "object") {
      violations.push(
        ...findUnsupportedSchemaKeywords(value, `${path}.${key}`, unsupportedKeywords),
      );
    }
  }
  return violations;
}

export function normalizeGeminiToolSchemas(
  ctx: ProviderNormalizeToolSchemasContext,
): AnyAgentTool[] {
  return ctx.tools.map((tool) => {
    if (!tool.parameters || typeof tool.parameters !== "object") {
      return tool;
    }
    return {
      ...tool,
      parameters: cleanSchemaForGemini(tool.parameters as Record<string, unknown>),
    };
  });
}

export function inspectGeminiToolSchemas(
  ctx: ProviderNormalizeToolSchemasContext,
): ProviderToolSchemaDiagnostic[] {
  return ctx.tools.flatMap((tool, toolIndex) => {
    const violations = findUnsupportedSchemaKeywords(
      tool.parameters,
      `${tool.name}.parameters`,
      GEMINI_UNSUPPORTED_SCHEMA_KEYWORDS,
    );
    if (violations.length === 0) {
      return [];
    }
    return [{ toolName: tool.name, toolIndex, violations }];
  });
}

export function normalizeOpenAIToolSchemas(
  ctx: ProviderNormalizeToolSchemasContext,
): AnyAgentTool[] {
  if (!shouldApplyOpenAIToolCompat(ctx)) {
    return ctx.tools;
  }
  return ctx.tools.map((tool) => {
    if (tool.parameters == null) {
      return {
        ...tool,
        parameters: normalizeOpenAIStrictCompatSchema({}),
      };
    }
    if (typeof tool.parameters !== "object") {
      return tool;
    }
    return {
      ...tool,
      parameters: normalizeOpenAIStrictCompatSchema(tool.parameters),
    };
  });
}

function normalizeOpenAIStrictCompatSchema(schema: unknown): unknown {
  return normalizeOpenAIStrictCompatSchemaRecursive(schema, { promoteEmptyObject: true });
}

function shouldApplyOpenAIToolCompat(ctx: ProviderNormalizeToolSchemasContext): boolean {
  const provider = (ctx.model?.provider ?? ctx.provider ?? "").trim().toLowerCase();
  const api = (ctx.model?.api ?? ctx.modelApi ?? "").trim().toLowerCase();
  const baseUrl = (ctx.model?.baseUrl ?? "").trim().toLowerCase();

  if (provider === "openai") {
    return api === "openai-responses" && (!baseUrl || isOpenAIResponsesBaseUrl(baseUrl));
  }
  if (provider === "openai-codex") {
    return (
      api === "openai-codex-responses" &&
      (!baseUrl || isOpenAIResponsesBaseUrl(baseUrl) || isOpenAICodexBaseUrl(baseUrl))
    );
  }
  return false;
}

function isOpenAIResponsesBaseUrl(baseUrl: string): boolean {
  return /^https:\/\/api\.openai\.com(?:\/v1)?(?:\/|$)/i.test(baseUrl);
}

function isOpenAICodexBaseUrl(baseUrl: string): boolean {
  return /^https:\/\/chatgpt\.com\/backend-api(?:\/|$)/i.test(baseUrl);
}

type NormalizeOpenAIStrictCompatOptions = {
  promoteEmptyObject: boolean;
};

const OPENAI_STRICT_COMPAT_SCHEMA_MAP_KEYS = new Set([
  "$defs",
  "definitions",
  "dependentSchemas",
  "patternProperties",
  "properties",
]);

const OPENAI_STRICT_COMPAT_SCHEMA_NESTED_KEYS = new Set([
  "additionalProperties",
  "allOf",
  "anyOf",
  "contains",
  "else",
  "if",
  "items",
  "not",
  "oneOf",
  "prefixItems",
  "propertyNames",
  "then",
  "unevaluatedItems",
  "unevaluatedProperties",
]);

function normalizeOpenAIStrictCompatSchemaMap(schema: unknown): unknown {
  if (!schema || typeof schema !== "object" || Array.isArray(schema)) {
    return schema;
  }

  let changed = false;
  const normalized: Record<string, unknown> = {};
  for (const [key, value] of Object.entries(schema as Record<string, unknown>)) {
    const next = normalizeOpenAIStrictCompatSchemaRecursive(value, {
      promoteEmptyObject: false,
    });
    normalized[key] = next;
    changed ||= next !== value;
  }
  return changed ? normalized : schema;
}

function normalizeOpenAIStrictCompatSchemaRecursive(
  schema: unknown,
  options: NormalizeOpenAIStrictCompatOptions,
): unknown {
  if (Array.isArray(schema)) {
    let changed = false;
    const normalized = schema.map((entry) => {
      const next = normalizeOpenAIStrictCompatSchemaRecursive(entry, {
        promoteEmptyObject: false,
      });
      changed ||= next !== entry;
      return next;
    });
    return changed ? normalized : schema;
  }
  if (!schema || typeof schema !== "object") {
    return schema;
  }

  const record = schema as Record<string, unknown>;
  let changed = false;
  const normalized: Record<string, unknown> = {};
  for (const [key, value] of Object.entries(record)) {
    const next = OPENAI_STRICT_COMPAT_SCHEMA_MAP_KEYS.has(key)
      ? normalizeOpenAIStrictCompatSchemaMap(value)
      : OPENAI_STRICT_COMPAT_SCHEMA_NESTED_KEYS.has(key)
        ? normalizeOpenAIStrictCompatSchemaRecursive(value, {
            promoteEmptyObject: false,
          })
        : value;
    normalized[key] = next;
    changed ||= next !== value;
  }

  if (Object.keys(normalized).length === 0) {
    if (!options.promoteEmptyObject) {
      return schema;
    }
    return {
      type: "object",
      properties: {},
      required: [],
      additionalProperties: false,
    };
  }

  const hasObjectShapeHints =
    !("type" in normalized) &&
    ((normalized.properties &&
      typeof normalized.properties === "object" &&
      !Array.isArray(normalized.properties)) ||
      Array.isArray(normalized.required));
  if (hasObjectShapeHints) {
    normalized.type = "object";
    changed = true;
  }
  if (normalized.type === "object" && !("properties" in normalized)) {
    normalized.properties = {};
    changed = true;
  }

  const hasEmptyProperties =
    normalized.properties &&
    typeof normalized.properties === "object" &&
    !Array.isArray(normalized.properties) &&
    Object.keys(normalized.properties as Record<string, unknown>).length === 0;

  if (normalized.type === "object" && !Array.isArray(normalized.required) && hasEmptyProperties) {
    normalized.required = [];
    changed = true;
  }

  if (
    normalized.type === "object" &&
    hasEmptyProperties &&
    !("additionalProperties" in normalized)
  ) {
    normalized.additionalProperties = false;
    changed = true;
  }

  return changed ? normalized : schema;
}

export function findOpenAIStrictSchemaViolations(
  schema: unknown,
  path: string,
  options?: { requireObjectRoot?: boolean },
): string[] {
  if (Array.isArray(schema)) {
    if (options?.requireObjectRoot) {
      return [`${path}.type`];
    }
    return schema.flatMap((item, index) =>
      findOpenAIStrictSchemaViolations(item, `${path}[${index}]`),
    );
  }
  if (!schema || typeof schema !== "object") {
    if (options?.requireObjectRoot) {
      return [`${path}.type`];
    }
    return [];
  }

  const record = schema as Record<string, unknown>;
  const violations: string[] = [];
  for (const key of ["anyOf", "oneOf", "allOf"] as const) {
    if (Array.isArray(record[key])) {
      violations.push(`${path}.${key}`);
    }
  }
  if (Array.isArray(record.type)) {
    violations.push(`${path}.type`);
  }

  const properties =
    record.properties && typeof record.properties === "object" && !Array.isArray(record.properties)
      ? (record.properties as Record<string, unknown>)
      : undefined;

  if (record.type === "object") {
    if (record.additionalProperties !== false) {
      violations.push(`${path}.additionalProperties`);
    }
    const required = Array.isArray(record.required)
      ? record.required.filter((entry): entry is string => typeof entry === "string")
      : undefined;
    if (!required) {
      violations.push(`${path}.required`);
    } else if (properties) {
      const requiredSet = new Set(required);
      for (const key of Object.keys(properties)) {
        if (!requiredSet.has(key)) {
          violations.push(`${path}.required.${key}`);
        }
      }
    }
  }

  if (properties) {
    for (const [key, value] of Object.entries(properties)) {
      violations.push(...findOpenAIStrictSchemaViolations(value, `${path}.properties.${key}`));
    }
  }

  for (const [key, value] of Object.entries(record)) {
    if (key === "properties") {
      continue;
    }
    if (value && typeof value === "object") {
      violations.push(...findOpenAIStrictSchemaViolations(value, `${path}.${key}`));
    }
  }

  return violations;
}

export function inspectOpenAIToolSchemas(
  ctx: ProviderNormalizeToolSchemasContext,
): ProviderToolSchemaDiagnostic[] {
  if (!shouldApplyOpenAIToolCompat(ctx)) {
    return [];
  }
  // Native OpenAI transports fall back to `strict: false` when any tool schema is not
  // strict-compatible, so these findings are expected for optional-heavy tool schemas.
  return [];
}

export type ProviderToolCompatFamily = "gemini" | "openai";

export function buildProviderToolCompatFamilyHooks(family: ProviderToolCompatFamily): {
  normalizeToolSchemas: (ctx: ProviderNormalizeToolSchemasContext) => AnyAgentTool[];
  inspectToolSchemas: (ctx: ProviderNormalizeToolSchemasContext) => ProviderToolSchemaDiagnostic[];
} {
  switch (family) {
    case "gemini":
      return {
        normalizeToolSchemas: normalizeGeminiToolSchemas,
        inspectToolSchemas: inspectGeminiToolSchemas,
      };
    case "openai":
      return {
        normalizeToolSchemas: normalizeOpenAIToolSchemas,
        inspectToolSchemas: inspectOpenAIToolSchemas,
      };
  }
  throw new Error("Unsupported provider tool compatibility family");
}