// luma.gl
// SPDX-License-Identifier: MIT
// Copyright (c) vis.gl contributors
import { ShaderModuleInstance } from "../shader-module/shader-module-instance.js";
/**
 * Instantiate shader modules and esolve any dependencies
 */
export function resolveModules(modules) {
    const instances = ShaderModuleInstance.instantiateModules(modules);
    return getShaderDependencies(instances);
}
/**
 * Takes a list of shader module names and returns a new list of
 * shader module names that includes all dependencies, sorted so
 * that modules that are dependencies of other modules come first.
 *
 * If the shader glsl code from the returned modules is concatenated
 * in the reverse order, it is guaranteed that all functions be resolved and
 * that all function and variable definitions come before use.
 *
 * @param modules - Array of modules (inline modules or module names)
 * @return - Array of modules
 */
function getShaderDependencies(modules) {
    const moduleMap = {};
    const moduleDepth = {};
    getDependencyGraph({ modules, level: 0, moduleMap, moduleDepth });
    // Return a reverse sort so that dependencies come before the modules that use them
    return Object.keys(moduleDepth)
        .sort((a, b) => moduleDepth[b] - moduleDepth[a])
        .map(name => moduleMap[name]);
}
/**
 * Recursively checks module dependencies to calculate dependency level of each module.
 *
 * @param options.modules - Array of modules
 * @param options.level - Current level
 * @param options.moduleMap -
 * @param options.moduleDepth - Current level
 * @return - Map of module name to its level
 */
// Adds another level of dependencies to the result map
export function getDependencyGraph(options) {
    const { modules, level, moduleMap, moduleDepth } = options;
    if (level >= 5) {
        throw new Error('Possible loop in shader dependency graph');
    }
    // Update level on all current modules
    for (const module of modules) {
        moduleMap[module.name] = module;
        if (moduleDepth[module.name] === undefined || moduleDepth[module.name] < level) {
            moduleDepth[module.name] = level;
        }
    }
    // Recurse
    for (const module of modules) {
        if (module.dependencies) {
            getDependencyGraph({ modules: module.dependencies, level: level + 1, moduleMap, moduleDepth });
        }
    }
}
export const TEST_EXPORTS = {
    getShaderDependencies,
    getDependencyGraph
};