import z, { type ZodType } from 'zod/v4';

import { jsonParse } from './utils';

const CredentialContextSchemaV1 = z.object({
	version: z.literal(1),
	/**
	 * Identity token/value used for credential resolution
	 * Could be JWT, API key, session token, user ID, etc.
	 */
	identity: z.string(),

	/**
	 * Optional metadata for credential resolution
	 */
	metadata: z.record(z.string(), z.unknown()).optional(),
});

export type ICredentialContextV1 = z.output<typeof CredentialContextSchemaV1>;

export const CredentialContextSchema = z
	.discriminatedUnion('version', [CredentialContextSchemaV1])
	.meta({
		title: 'ICredentialContext',
	});

/**
 * Decrypted structure of credentials field
 * Never stored in this form - always encrypted in IExecutionContext
 */
export type ICredentialContext = z.output<typeof CredentialContextSchema>;

const WorkflowExecuteModeSchema = z.union([
	z.literal('cli'),
	z.literal('error'),
	z.literal('integrated'),
	z.literal('internal'),
	z.literal('manual'),
	z.literal('retry'),
	z.literal('trigger'),
	z.literal('webhook'),
	z.literal('evaluation'),
	z.literal('chat'),
]);

export type WorkflowExecuteModeValues = z.infer<typeof WorkflowExecuteModeSchema>;

const ExecutionContextSchemaV1 = z.object({
	version: z.literal(1),
	/**
	 * When the context was established (Unix timestamp in milliseconds)
	 */
	establishedAt: z.number(),

	/**
	 * The mode in which the workflow is being executed
	 */
	source: WorkflowExecuteModeSchema,

	/**
	 * Optional node where execution started
	 */
	triggerNode: z
		.object({
			name: z.string(),
			type: z.string(),
		})
		.optional(),

	/**
	 * Optional ID of the parent execution, if this is set this
	 * execution context inherited from the mentioned parent execution context.
	 */
	parentExecutionId: z.string().optional(),

	/**
	 * Encrypted credential context for dynamic credential resolution
	 * Always encrypted when stored, decrypted on-demand by credential resolver
	 * @see ICredentialContext for decrypted structure
	 */
	credentials: z.string().optional().meta({
		description:
			'Encrypted credential context for dynamic credential resolution Always encrypted when stored, decrypted on-demand by credential resolver @see ICredentialContext for decrypted structure',
	}),
});

export type IExecutionContextV1 = z.output<typeof ExecutionContextSchemaV1>;

export const ExecutionContextSchema = z
	.discriminatedUnion('version', [ExecutionContextSchemaV1])
	.meta({
		title: 'IExecutionContext',
	});

/**
 * Execution context carries per-execution metadata throughout workflow lifecycle
 * Established at execution start and propagated to sub-workflows/error workflows
 */
export type IExecutionContext = z.output<typeof ExecutionContextSchema>;

/**
 * Runtime representation of execution context with decrypted credential data.
 *
 * This type is identical to IExecutionContext except the `credentials` field
 * contains the decrypted ICredentialContext object instead of an encrypted string.
 *
 * **Usage contexts:**
 * - Hook execution: Hooks work with plaintext context to extract/merge credential data
 * - Credential resolution: Resolvers need decrypted identity tokens
 * - Internal processing: Runtime operations that need access to credential context
 *
 * **Security notes:**
 * - Never persist this type to database - use IExecutionContext with encrypted credentials
 * - Never expose in API responses or logs
 * - Only exists in-memory during workflow execution
 * - Should be cleared from memory after use
 *
 * **Lifecycle:**
 * 1. Load IExecutionContext from storage (credentials encrypted)
 * 2. Decrypt credentials field → PlaintextExecutionContext (runtime only)
 * 3. Use for hook execution, credential resolution, etc.
 * 4. Encrypt credentials → IExecutionContext before persistence
 *
 * @see IExecutionContext - Persisted form with encrypted credentials
 * @see ICredentialContext - Decrypted credential structure
 * @see IExecutionContextUpdate - Partial updates during hook execution
 *
 * @example
 * ```typescript
 * // During hook execution:
 * const plaintextContext: PlaintextExecutionContext = {
 *   ...context,
 *   credentials: decryptCredentials(context.credentials) // Decrypt for runtime use
 * };
 *
 * // Hook can now access plaintext credential data
 * const identity = plaintextContext.credentials?.identity;
 *
 * // Before storage, re-encrypt:
 * const storableContext: IExecutionContext = {
 *   ...plaintextContext,
 *   credentials: encryptCredentials(plaintextContext.credentials)
 * };
 * ```
 */
export type PlaintextExecutionContext = Omit<IExecutionContext, 'credentials'> & {
	credentials?: ICredentialContext;
};

export const safeParse = <T extends ZodType>(value: string | object, schema: T) => {
	const typeName = schema.meta()?.title ?? 'Object';
	try {
		const normalizedObject = typeof value === 'string' ? jsonParse(value) : value;
		const parseResult = schema.safeParse(normalizedObject);
		if (parseResult.error) {
			throw parseResult.error;
		}
		// here we could implement a mgiration policy for migrating old execution context versions to newer ones
		return parseResult.data;
	} catch (error) {
		throw new Error(`Failed to parse to valid ${typeName}`, {
			cause: error,
		});
	}
};

/**
 * Safely parses an execution context from an
 * @param obj
 * @returns
 */
export const toExecutionContext = (value: string | object): IExecutionContext => {
	// here we could implement a mgiration policy for migrating old execution context versions to newer ones
	return safeParse(value, ExecutionContextSchema);
};

/**
 * Safely parses a credential context from either an object or a string to an
 * ICredentialContext. This can be used to safely parse a decrypted context for
 * example.
 * @param value The object or string to be parsed
 * @returns ICredentialContext
 * @throws Error in case parsing fails for any reason
 */
export const toCredentialContext = (value: string | object): ICredentialContext => {
	// here we could implement a mgiration policy for migrating old credential context versions to newer ones
	return safeParse(value, CredentialContextSchema);
};