/**
 * Physics Tools
 *
 * Tools for FEA explanations and method recommendations.
 */

import { readdir, readFile } from "fs/promises";
import { resolve } from "path";
import { AtomizerTool } from "../index.js";
import { ATOMIZER_ROOT, OPTIMIZATION_ENGINE_DIR } from "../utils/paths.js";

// Physics concepts knowledge base
const PHYSICS_CONCEPTS: Record<string, string> = {
  displacement: `
**Displacement** is the change in position of a point in a structure under load.
In FEA, nodal displacements are the primary unknowns solved for.

Key metrics:
- Maximum displacement: Largest movement in any direction
- RMS displacement: Root-mean-square of all nodal displacements
- Directional displacement: Movement in a specific axis (X, Y, or Z)

Units: millimeters (mm) or inches (in)

Atomizer extractors: extract_displacement, extract_max_displacement
`,

  stress: `
**Stress** is the internal force per unit area within a material.
In FEA, stress is computed from strain (displacement gradients).

Types:
- Von Mises stress: Combined stress for ductile materials (most common)
- Principal stresses: Maximum/minimum normal stresses
- Shear stress: Stress parallel to a surface

Key considerations:
- Compare to material yield strength for safety factor
- Stress concentrations occur at corners, holes, and thickness changes

Units: MPa (N/mm²) or psi

Atomizer extractors: extract_solid_stress, extract_von_mises_stress
`,

  frequency: `
**Natural Frequency** is the rate at which a structure vibrates when disturbed.
Modal analysis finds these frequencies and their corresponding mode shapes.

Key concepts:
- Fundamental frequency: Lowest natural frequency (Mode 1)
- Mode shape: Pattern of vibration at each frequency
- Resonance: When excitation frequency matches natural frequency (dangerous!)

Design goals:
- Keep natural frequencies above or below operating frequencies
- Separate modes to avoid coupling

Units: Hz (cycles/second)

Atomizer extractors: extract_frequency, extract_modal_participation
`,

  mass: `
**Mass** is the total material quantity in a structure.
In optimization, mass is often a key objective to minimize.

Calculation methods:
- From CAD: NX expression-based calculation (most accurate)
- From FEM: Sum of element masses (approximation)
- From BDF: Calculated from element properties

Related metrics:
- Center of gravity (CG): Balance point
- Moments of inertia: Rotational mass distribution

Units: kg or lbm

Atomizer extractors: extract_mass_from_expression, extract_mass_from_bdf
`,

  zernike: `
**Zernike Polynomials** are mathematical functions for describing optical aberrations.
Used to characterize mirror surface deformation in precision optics.

Key coefficients:
- Z4 (Defocus): Curvature change
- Z5, Z6 (Astigmatism): Cylindrical deformation
- Z7, Z8 (Coma): Comet-like aberration
- Z11 (Spherical): Radial curvature variation

Fitting method:
1. Extract nodal displacements from FEA
2. Fit to Zernike polynomial basis
3. Report RMS WFE (wavefront error)

Units: nanometers (nm) or waves

Atomizer extractors: extract_zernike_figure, extract_zernike_annular
`,

  convergence: `
**Optimization Convergence** indicates when the search has found a good solution.

Signs of convergence:
- Best value stops improving for many trials
- Low variance in recent trial results
- Improvement rate drops below threshold

When to stop:
- Converged: Best hasn't improved in 20+ trials
- Plateau: Improvement rate < 1% per 10 trials
- Budget exhausted: Reached max_trials

Tips:
- Don't stop too early - TPE needs ~50 trials to learn
- Consider switching to local optimizer after convergence
- Check multiple random seeds for robustness
`,
};

// Method recommendation logic
const METHOD_RECOMMENDATIONS: Record<string, { method: string; reason: string }> = {
  "1_obj_few_dv": {
    method: "TPE",
    reason: "Tree-structured Parzen Estimator works well for single-objective with few design variables. It balances exploration and exploitation efficiently.",
  },
  "1_obj_many_dv": {
    method: "CMA-ES",
    reason: "Covariance Matrix Adaptation is effective for high-dimensional single-objective problems. It learns correlations between variables.",
  },
  "multi_obj": {
    method: "NSGA-II",
    reason: "Non-dominated Sorting Genetic Algorithm II finds Pareto-optimal solutions for multi-objective problems. Good for exploring trade-offs.",
  },
  "noisy": {
    method: "RandomSearch + averaging",
    reason: "For noisy objectives, random search with trial averaging is robust. Consider multiple FEA runs per trial.",
  },
  "expensive": {
    method: "TPE + surrogate",
    reason: "For expensive FEA (>5 min/eval), use TPE with neural network surrogate for pre-screening. See SYS_14 Neural Acceleration.",
  },
};

export const physicsTools: AtomizerTool[] = [
  {
    definition: {
      name: "explain_physics",
      description:
        "Explain FEA physics concepts relevant to optimization. Use this to help users understand displacement, stress, frequency, mass, or other physics quantities.",
      inputSchema: {
        type: "object" as const,
        properties: {
          concept: {
            type: "string",
            enum: [
              "displacement",
              "stress",
              "frequency",
              "mass",
              "zernike",
              "convergence",
            ],
            description: "The physics concept to explain",
          },
          context: {
            type: "string",
            description:
              "Optional context about the user's situation for tailored explanation",
          },
        },
        required: ["concept"],
      },
    },
    handler: async (args) => {
      const concept = args.concept as string;
      const context = args.context as string | undefined;

      const explanation = PHYSICS_CONCEPTS[concept];

      if (!explanation) {
        return {
          content: [
            {
              type: "text",
              text: `Unknown concept: ${concept}. Available concepts: ${Object.keys(PHYSICS_CONCEPTS).join(", ")}`,
            },
          ],
          isError: true,
        };
      }

      let response = explanation.trim();

      if (context) {
        response += `\n\n---\n\n**For your context** (${context}):\n`;
        response +=
          "Consider how this concept applies to your specific optimization goals.";
      }

      return {
        content: [
          {
            type: "text",
            text: response,
          },
        ],
      };
    },
  },

  {
    definition: {
      name: "recommend_method",
      description:
        "Recommend an optimization method based on problem characteristics. Considers number of objectives, design variables, noise level, and evaluation cost.",
      inputSchema: {
        type: "object" as const,
        properties: {
          num_objectives: {
            type: "number",
            description: "Number of objectives (1 for single-objective)",
          },
          num_design_variables: {
            type: "number",
            description: "Number of design variables",
          },
          evaluation_time_minutes: {
            type: "number",
            description: "Approximate time for one FEA evaluation in minutes",
          },
          is_noisy: {
            type: "boolean",
            description: "Whether the objective has noise/variability",
          },
          budget_trials: {
            type: "number",
            description: "Maximum number of trials you can afford",
          },
        },
        required: ["num_objectives", "num_design_variables"],
      },
    },
    handler: async (args) => {
      const numObjectives = args.num_objectives as number;
      const numDV = args.num_design_variables as number;
      const evalTime = (args.evaluation_time_minutes as number) || 1;
      const isNoisy = args.is_noisy as boolean;
      const budget = (args.budget_trials as number) || 100;

      let key: string;

      if (isNoisy) {
        key = "noisy";
      } else if (numObjectives > 1) {
        key = "multi_obj";
      } else if (evalTime > 5) {
        key = "expensive";
      } else if (numDV > 10) {
        key = "1_obj_many_dv";
      } else {
        key = "1_obj_few_dv";
      }

      const rec = METHOD_RECOMMENDATIONS[key];

      const response = {
        recommended_method: rec.method,
        reason: rec.reason,
        problem_characteristics: {
          objectives: numObjectives,
          design_variables: numDV,
          evaluation_time_minutes: evalTime,
          is_noisy: isNoisy,
          budget: budget,
        },
        estimated_trials_needed: numObjectives === 1 ? Math.min(budget, 50 + numDV * 5) : Math.min(budget, 100 + numDV * 10),
        tips: [
          `With ${numDV} design variables, expect ~${Math.min(budget, 30 + numDV * 3)} trials before meaningful convergence.`,
          evalTime > 5
            ? "Consider using neural surrogate acceleration (see SYS_14)."
            : "Standard optimization should work well.",
          budget < 50 ? "Low budget - consider random search for baseline first." : "",
        ].filter(Boolean),
      };

      return {
        content: [
          {
            type: "text",
            text: JSON.stringify(response, null, 2),
          },
        ],
      };
    },
  },

  {
    definition: {
      name: "query_extractors",
      description:
        "List available physics extractors in Atomizer for extracting results from FEA solutions.",
      inputSchema: {
        type: "object" as const,
        properties: {
          physics_type: {
            type: "string",
            enum: [
              "displacement",
              "stress",
              "frequency",
              "mass",
              "zernike",
              "all",
            ],
            description: "Filter by physics type, or 'all' for complete list",
          },
        },
      },
    },
    handler: async (args) => {
      const physicsType = (args.physics_type as string) || "all";
      const extractorsDir = resolve(OPTIMIZATION_ENGINE_DIR, "extractors");

      try {
        const files = await readdir(extractorsDir);
        const extractorFiles = files.filter(
          (f) => f.startsWith("extract_") && f.endsWith(".py")
        );

        const extractors: { name: string; physics: string; file: string }[] = [];

        for (const file of extractorFiles) {
          const name = file.replace("extract_", "").replace(".py", "");

          // Determine physics type from name
          let physics: string;
          if (name.includes("displacement") || name.includes("deform")) {
            physics = "displacement";
          } else if (name.includes("stress") || name.includes("mises")) {
            physics = "stress";
          } else if (name.includes("freq") || name.includes("modal")) {
            physics = "frequency";
          } else if (name.includes("mass") || name.includes("weight")) {
            physics = "mass";
          } else if (name.includes("zernike") || name.includes("wfe")) {
            physics = "zernike";
          } else {
            physics = "other";
          }

          if (physicsType === "all" || physics === physicsType) {
            extractors.push({ name, physics, file });
          }
        }

        // Read __init__.py for exported functions
        const initPath = resolve(extractorsDir, "__init__.py");
        let exports: string[] = [];
        try {
          const initContent = await readFile(initPath, "utf-8");
          const match = initContent.match(/__all__\s*=\s*\[([\s\S]*?)\]/);
          if (match) {
            exports = match[1]
              .split(",")
              .map((s) => s.trim().replace(/['"]/g, ""))
              .filter(Boolean);
          }
        } catch {
          // Ignore if __init__.py not readable
        }

        return {
          content: [
            {
              type: "text",
              text: JSON.stringify(
                {
                  filter: physicsType,
                  count: extractors.length,
                  extractors,
                  exported_functions: exports,
                  usage_example:
                    "from optimization_engine.extractors import extract_displacement",
                },
                null,
                2
              ),
            },
          ],
        };
      } catch (error) {
        const message = error instanceof Error ? error.message : String(error);
        return {
          content: [
            {
              type: "text",
              text: `Error listing extractors: ${message}`,
            },
          ],
          isError: true,
        };
      }
    },
  },
];