import type { RawTypesConfig } from "@graphql-codegen/visitor-plugin-common";

/**
 * Mock data generation options (user input - all fields optional).
 *
 * Mock generation uses two complementary depth controls:
 * - `maxDepth`: Limits total nesting depth across ALL types (A → B → C → D stops at depth limit)
 * - `maxTypeRecursion`: Limits how many times the SAME type can appear in a chain (User → User → User)
 *
 * Both conditions must pass for generation to continue:
 * `depth < maxDepth && typeVisitCount[type] < maxTypeRecursion`
 */
export type RawMockConfig = {
    /**
     * Maximum total nesting depth across all types.
     * Prevents deep chains like: Query → Book → Author → Publisher → Address → Country → ...
     * @default 9
     * @example
     * // With maxDepth: 3, generation stops at depth 3 regardless of type
     * // Query(0) → Book(1) → Author(2) → Publisher(3) → stops
     */
    maxDepth?: number | undefined;
    /**
     * Maximum times a specific type can be visited in a single path.
     * Prevents same-type recursion like: User → User → User → ...
     * @default 2
     * @example
     * // With maxTypeRecursion: 2
     * // User(visit:1) → friends: User(visit:2) → friends: undefined (stops)
     */
    maxTypeRecursion?: number | undefined;
    /**
     * Number of elements to generate for array/list fields.
     * @default 3
     */
    listLength?: number | undefined;
    /**
     * Default values for GraphQL scalar types.
     */
    defaultValues?:
        | {
              String?: string | undefined;
              Int?: number | undefined;
              Float?: number | undefined;
              Boolean?: boolean | undefined;
              ID?: string | undefined;
              CustomScalar?: {
                  /**
                   * CustomScalar default expression
                   * The value must be an JavaScript expression.
                   * If you want to put a string value, you must put it in quotes
                   * @example
                   * ```js
                   * CustomScalar: {
                   *   Digit: "1",
                   *   DateYYYYMMDD: "'2022-02-03'",
                   *   ISODateTime: "new Date().toISOString()"
                   * }
                   * ```
                   */
                  [key: string]: string;
              };
          }
        | undefined;
};

/**
 * Code generation config (user input - all fields optional).
 * Used by graphql-codegen plugin to generate mock factory functions.
 */
export type RawConfig = {
    /**
     * Path to type definitions file generated by graphql-codegen client preset.
     * Required for TypeScript output.
     * @example "typeFile: "./graphql"
     */
    typesFile?: string | undefined;
    /**
     * Whether to skip __typename field in generated types.
     * @see https://the-guild.dev/graphql/codegen/plugins/typescript/typescript#skiptypename
     */
    skipTypename?: RawTypesConfig["skipTypename"] | undefined;
    /**
     * Naming convention for generated types.
     * @see https://the-guild.dev/graphql/codegen/plugins/typescript/typescript#namingconvention
     */
    namingConvention?: RawTypesConfig["namingConvention"] | undefined;
    /**
     * Prefix for generated type names.
     */
    typesPrefix?: RawTypesConfig["typesPrefix"] | undefined;
    /**
     * Suffix for generated type names.
     */
    typesSuffix?: RawTypesConfig["typesSuffix"] | undefined;
    /**
     * Mock data generation options.
     * Controls depth limits, list lengths, and default scalar values.
     */
    mock?: RawMockConfig | undefined;
};

/**
 * Default values for mock generation options.
 */
export const MockDefaults = {
    /** @see RawMockConfig.maxDepth */
    maxDepth: 9,
    /** @see RawMockConfig.maxTypeRecursion */
    maxTypeRecursion: 2,
    /** @see RawMockConfig.listLength */
    listLength: 3,
} as const;

/**
 * Default values for GraphQL scalar types.
 */
export const DefaultValues = {
    String: "string",
    Int: 12,
    Float: 12.3,
    Boolean: true,
    ID: "xxxx-xxxx-xxxx-xxxx",
} as const;

/**
 * Mock data generation options (normalized - all fields required).
 * This is the internal config type with defaults applied.
 *
 * @see RawMockConfig for user-facing config with optional fields
 */
export type MockConfig = {
    /**
     * Maximum total nesting depth across all types.
     * @see RawMockConfig.maxDepth
     */
    maxDepth: number;
    /**
     * Maximum times a specific type can be visited in a single path.
     * @see RawMockConfig.maxTypeRecursion
     */
    maxTypeRecursion: number;
    /**
     * Number of elements to generate for array/list fields.
     */
    listLength: number;
    /**
     * Default values for GraphQL scalar types.
     */
    defaultValues: {
        /** Default value for String scalar */
        String: string;
        /** Default value for Int scalar */
        Int: number;
        /** Default value for Float scalar */
        Float: number;
        /** Default value for Boolean scalar */
        Boolean: boolean;
        /** Default value for ID scalar */
        ID: string;
        /**
         * Default values for custom scalars.
         * Key is the scalar name, value is a JavaScript expression.
         */
        CustomScalar?: {
            [key: string]: string;
        };
    };
};

/**
 * Code generation config (normalized - all fields required).
 * This is the internal config type with defaults applied.
 *
 * @see RawConfig for user-facing config with optional fields
 */
export type Config = {
    /** Path to type definitions file */
    typesFile: string;
    /** Whether to skip __typename field */
    skipTypename: Exclude<RawTypesConfig["skipTypename"], undefined>;
    /** Prefix for generated type names */
    typesPrefix: Exclude<RawTypesConfig["typesPrefix"], undefined>;
    /** Suffix for generated type names */
    typesSuffix: Exclude<RawTypesConfig["typesSuffix"], undefined>;
    /** Naming convention for generated types */
    namingConvention: Exclude<RawTypesConfig["namingConvention"], undefined>;
    /** Mock data generation options (normalized) */
    mock: MockConfig;
};

export function validateConfig(
    rawConfig: unknown,
    outputType: "typescript" | "javascript" = "javascript",
): asserts rawConfig is RawConfig {
    if (rawConfig === null || rawConfig === undefined) {
        throw new Error("config must be an object");
    }
    if (typeof rawConfig !== "object") {
        throw new Error("config must be an object");
    }
    if (outputType === "typescript") {
        if (!("typesFile" in rawConfig)) {
            throw new Error("config.typesFile is required");
        }
    }
    if ("mock" in rawConfig && rawConfig.mock !== undefined) {
        if (typeof rawConfig.mock !== "object") {
            throw new Error("config.mock must be an object");
        }
        const mock = rawConfig.mock as RawMockConfig;
        if (mock.maxDepth !== undefined && typeof mock.maxDepth !== "number") {
            throw new Error("config.mock.maxDepth must be a number");
        }
        if (mock.maxDepth !== undefined && mock.maxDepth < 1) {
            throw new Error("config.mock.maxDepth must be at least 1");
        }
        if (mock.maxTypeRecursion !== undefined && typeof mock.maxTypeRecursion !== "number") {
            throw new Error("config.mock.maxTypeRecursion must be a number");
        }
        if (mock.maxTypeRecursion !== undefined && mock.maxTypeRecursion < 1) {
            throw new Error("config.mock.maxTypeRecursion must be at least 1");
        }
        if (mock.listLength !== undefined && typeof mock.listLength !== "number") {
            throw new Error("config.mock.listLength must be a number");
        }
        if (mock.defaultValues !== undefined) {
            if (typeof mock.defaultValues !== "object") {
                throw new Error("config.mock.defaultValues must be an object");
            }
            const defaultValues = mock.defaultValues;
            if (defaultValues.String !== undefined && typeof defaultValues.String !== "string") {
                throw new Error("config.mock.defaultValues.String must be a string");
            }
            if (defaultValues.Int !== undefined && typeof defaultValues.Int !== "number") {
                throw new Error("config.mock.defaultValues.Int must be a number");
            }
            if (defaultValues.Float !== undefined && typeof defaultValues.Float !== "number") {
                throw new Error("config.mock.defaultValues.Float must be a number");
            }
            if (defaultValues.Boolean !== undefined && typeof defaultValues.Boolean !== "boolean") {
                throw new Error("config.mock.defaultValues.Boolean must be a boolean");
            }
            if (defaultValues.ID !== undefined && typeof defaultValues.ID !== "string") {
                throw new Error("config.mock.defaultValues.ID must be a string");
            }
            if (
                defaultValues.CustomScalar !== undefined &&
                typeof defaultValues.CustomScalar !== "object"
            ) {
                throw new Error("config.mock.defaultValues.CustomScalar must be an object");
            }
        }
    }
}

export function normalizeConfig(rawConfig: RawConfig): Config {
    return {
        typesFile: rawConfig.typesFile ?? "",
        skipTypename: rawConfig.skipTypename ?? false,
        typesPrefix: rawConfig.typesPrefix ?? "",
        typesSuffix: rawConfig.typesSuffix ?? "",
        namingConvention: rawConfig.namingConvention ?? "",
        mock: {
            maxDepth: rawConfig.mock?.maxDepth ?? MockDefaults.maxDepth,
            maxTypeRecursion: rawConfig.mock?.maxTypeRecursion ?? MockDefaults.maxTypeRecursion,
            listLength: rawConfig.mock?.listLength ?? MockDefaults.listLength,
            defaultValues: {
                String: rawConfig.mock?.defaultValues?.String ?? DefaultValues.String,
                Int: rawConfig.mock?.defaultValues?.Int ?? DefaultValues.Int,
                Float: rawConfig.mock?.defaultValues?.Float ?? DefaultValues.Float,
                Boolean: rawConfig.mock?.defaultValues?.Boolean ?? DefaultValues.Boolean,
                ID: rawConfig.mock?.defaultValues?.ID ?? DefaultValues.ID,
                CustomScalar: rawConfig.mock?.defaultValues?.CustomScalar ?? {},
            },
        },
    };
}