Context.kt

package de.zalando.zally.rule

import com.fasterxml.jackson.core.JsonPointer
import de.zalando.zally.rule.api.Violation
import de.zalando.zally.util.ast.JsonPointers
import de.zalando.zally.util.ast.MethodCallRecorder
import de.zalando.zally.util.ast.ReverseAst
import io.swagger.models.Swagger
import io.swagger.parser.SwaggerParser
import io.swagger.v3.oas.models.OpenAPI
import io.swagger.v3.oas.models.Operation
import io.swagger.v3.oas.models.PathItem
import io.swagger.v3.oas.models.PathItem.HttpMethod
import io.swagger.v3.oas.models.media.Schema
import io.swagger.v3.oas.models.parameters.Parameter
import io.swagger.v3.parser.OpenAPIV3Parser
import io.swagger.v3.parser.converter.SwaggerConverter
import io.swagger.v3.parser.core.models.ParseOptions
import io.swagger.v3.parser.util.ResolverFully
import org.slf4j.LoggerFactory

class Context(private val openApi: OpenAPI, swagger: Swagger? = null) {
    private val recorder = MethodCallRecorder(openApi).skipMethods(*extensionNames)
    private val openApiAst = ReverseAst.fromObject(openApi).withExtensionMethodNames(*extensionNames).build()
    private val swaggerAst = swagger?.let { ReverseAst.fromObject(it).withExtensionMethodNames(*extensionNames).build() }

    val api = recorder.proxy
    val unrecordedApi = openApi

    /**
     * Convenience method for filtering and iterating over the paths in order to create Violations.
     * @param pathFilter a filter selecting the paths to validate
     * @param action the action to perform on filtered items
     * @return a list of Violations
     */
    fun validatePaths(
        pathFilter: (Map.Entry<String, PathItem>) -> Boolean = { true },
        action: (Map.Entry<String, PathItem>) -> List<Violation?>
    ): List<Violation> = api.paths
            .orEmpty()
            .filter(pathFilter)
            .flatMap(action)
            .filterNotNull()

    /**
     * Convenience method for filtering and iterating over the operations in order to create Violations.
     * @param pathFilter a filter selecting the paths to validate
     * @param operationFilter a filter selecting the operations to validate
     * @param action the action to perform on filtered items
     * @return a list of Violations
     */
    fun validateOperations(
        pathFilter: (Map.Entry<String, PathItem>) -> Boolean = { true },
        operationFilter: (Map.Entry<HttpMethod, Operation>) -> Boolean = { true },
        action: (Map.Entry<HttpMethod, Operation>) -> List<Violation?>
    ): List<Violation> = validatePaths(pathFilter) { (_, path) ->
        path.readOperationsMap()
            .orEmpty()
            .filter(operationFilter)
            .flatMap(action)
            .filterNotNull()
    }

    /**
     * Convenience method for filtering and iterating over the schemas in order to create Violations.
     * @param schemaFilter a filter selecting the schemas to validate
     * @param action the action to perform on filtered items
     * @return a list of Violations
     */
    fun validateSchemas(
        schemaFilter: (Map.Entry<String, Schema<*>>) -> Boolean = { true },
        action: (Map.Entry<String, Schema<*>>) -> List<Violation?>
    ): List<Violation> = api.components.schemas
        .orEmpty()
        .filter(schemaFilter)
        .flatMap(action)
        .filterNotNull()

    /**
     * Convenience method for filtering and iterating over the parameters in order to create Violations.
     * @param parameterFilter a filter selecting the parameters to validate
     * @param action the action to perform on filtered items
     * @return a list of Violations
     */
    fun validateParameters(
        parameterFilter: (Map.Entry<String, Parameter>) -> Boolean = { true },
        action: (Map.Entry<String, Parameter>) -> List<Violation?>
    ): List<Violation> = api.components.parameters
        .orEmpty()
        .filter(parameterFilter)
        .flatMap(action)
        .filterNotNull()

    /**
     * Creates a List of one Violation with a pointer to the OpenAPI or Swagger model node specified,
     * defaulting to the last recorded location.
     * @param description the description of the Violation
     * @param value the OpenAPI or Swagger model node
     * @return the new Violation
     */
    fun violations(description: String, value: Any): List<Violation> =
            listOf(violation(description, value))

    /**
     * Creates a List of one Violation with the specified pointer, defaulting to the last recorded location.
     * @param description the description of the Violation
     * @param pointer an existing pointer or null
     * @return the new Violation
     */
    fun violations(description: String, pointer: JsonPointer?): List<Violation> =
            listOf(violation(description, pointer))

    /**
     * Creates a Violation with a pointer to the OpenAPI or Swagger model node specified,
     * defaulting to the last recorded location.
     * @param description the description of the Violation
     * @param value the OpenAPI or Swagger model node
     * @return the new Violation
     */
    fun violation(description: String, value: Any): Violation =
            violation(description, pointerForValue(value))

    /**
     * Creates a Violation with the specified pointer, defaulting to the last recorded location.
     * @param description the description of the Violation
     * @param pointer an existing pointer or null
     * @return the new Violation
     */
    fun violation(description: String, pointer: JsonPointer? = null): Violation =
            Violation(description, pointer ?: recorder.pointer)

    /**
     * Checks whether a location should be ignored by a specific rule.
     * @param pointer the location to check
     * @param ruleId the rule id to check
     * @return true if the location should be ignored for this rule
     */
    fun isIgnored(pointer: JsonPointer, ruleId: String): Boolean =
            swaggerAst?.isIgnored(pointer, ruleId) ?: openApiAst.isIgnored(pointer, ruleId)

    /**
     * Gets a [JsonPointer] reference to a given [value].
     * @param value the value for which we want a pointer
     * @return a [JsonPointer] reference to the [value] or `null` if it was not found.
     */
    fun pointerForValue(value: Any): JsonPointer? = if (swaggerAst != null) {
        val swaggerPointer = swaggerAst.getPointer(value)
        if (swaggerPointer != null)
            swaggerPointer
        else {
            // Attempt to convert an OpenAPI pointer to a Swagger pointer.
            val openApiPointer = openApiAst.getPointer(value)
            JsonPointers.convertPointer(openApiPointer) ?: openApiPointer
        }
    } else {
        openApiAst.getPointer(value)
    }

    companion object {
        private val log = LoggerFactory.getLogger(Context::class.java)
        val extensionNames = arrayOf("getVendorExtensions", "getExtensions")

        fun createOpenApiContext(content: String): Context? {
            val parseOptions = ParseOptions()
            parseOptions.isResolve = true
            // parseOptions.isResolveFully = true // https://github.com/swagger-api/swagger-parser/issues/682

            return OpenAPIV3Parser().readContents(content, null, parseOptions)?.openAPI?.let {
                ResolverFully(true).resolveFully(it) // workaround for NPE bug in swagger-parser
                Context(it)
            }
        }

        fun createSwaggerContext(content: String): Context? =
            SwaggerParser().readWithInfo(content, true)?.let {
                val swagger = it.swagger ?: return null
                val conversion = SwaggerConverter().convert(it)
                val openApi = conversion?.openAPI

                openApi?.let {
                    try {
                        ResolverFully(true).resolveFully(it)
                    } catch (e: NullPointerException) {
                        log.warn("Failed to fully resolve Swagger schema.", e)
                    }
                    Context(it, swagger)
                }
            }
    }
}