#!/usr/bin/env bun
/**
 * MEMLNaut MIDI device-template codegen.
 *
 * Reads:   schemas/midi_device.schema.json (Draft 2020-12 meta-schema)
 *          schemas/midi_devices/*.json     (one file per external MIDI device)
 *
 * Writes:  nisps/midi/generated/midi_devices.hpp                (no-heap constexpr, firmware + WASM)
 *          manifold/src/midi-devices/generated/types.ts         (shared TS types)
 *          manifold/src/midi-devices/generated/devices.ts       (device catalogue)
 *          manifold/src/midi-devices/generated/index.ts         (re-exports)
 *
 * One source of truth -> both surfaces. The performer picks a device, sees its params
 * by name, and selects which the ML drives over MIDI CC. Idempotent: regenerating the
 * same schemas yields byte-identical output. Exits non-zero on validation failure.
 *
 * Deliberately separate from codegen/generate.ts (the mode-schema pipeline) so it cannot
 * disturb the mode golden test.
 */

import { readFileSync, writeFileSync, readdirSync, mkdirSync, existsSync } from "node:fs";
import { join, dirname, resolve } from "node:path";
import { fileURLToPath } from "node:url";
import Ajv2020, { type AnySchemaObject } from "ajv/dist/2020.js";

// ----- Types ----------------------------------------------------------------

interface DeviceParam {
  id: string;
  cc: number;
  label: string;
  min: number;
  max: number;
  default: number;
  group: string;
  notes?: string;
}

interface DeviceSchema {
  $schema?: string;
  _note?: string;
  device_id: string;
  name: string;
  manufacturer: string;
  year?: number;
  midi: {
    default_channel: number;
    value_range: [number, number];
    notes?: string;
  };
  params: DeviceParam[];
}

// ----- Paths ----------------------------------------------------------------

const __dirname = dirname(fileURLToPath(import.meta.url));
const REPO_ROOT = resolve(__dirname, "..");
const SCHEMAS_DIR = join(REPO_ROOT, "schemas");
const DEVICES_DIR = join(SCHEMAS_DIR, "midi_devices");
const META_SCHEMA_PATH = join(SCHEMAS_DIR, "midi_device.schema.json");
const CPP_OUT_DIR = join(REPO_ROOT, "nisps", "midi", "generated");
const TS_OUT_DIR = join(REPO_ROOT, "manifold", "src", "midi-devices", "generated");

// ----- Helpers --------------------------------------------------------------

function ensureDir(d: string): void {
  if (!existsSync(d)) mkdirSync(d, { recursive: true });
}
function readJSON<T>(path: string): T {
  return JSON.parse(readFileSync(path, "utf8")) as T;
}
function toPascalCase(snake: string): string {
  return snake.split("_").map(s => (s.length === 0 ? s : s[0].toUpperCase() + s.slice(1))).join("");
}
function cppStringLit(s: string): string {
  return '"' + s.replace(/\\/g, "\\\\").replace(/"/g, '\\"') + '"';
}
function tsStringLit(s: string): string {
  return "'" + s.replace(/\\/g, "\\\\").replace(/'/g, "\\'") + "'";
}

const BANNER = "// AUTOGENERATED — do not edit. Source: schemas/midi_devices/*.json. " +
  "Run `bun run codegen/generate-midi-devices.ts` to regenerate.";

// ----- C++ emission ---------------------------------------------------------

function emitCppHeader(devices: DeviceSchema[]): string {
  const L: string[] = [];
  L.push(BANNER);
  L.push("//");
  L.push("// No-heap, constexpr MIDI device templates for the RP2350 firmware (and WASM).");
  L.push("// Names are std::string_view into flash; CC/value fields are uint8_t.");
  L.push("#ifndef NISPS_MIDI_GENERATED_MIDI_DEVICES_HPP");
  L.push("#define NISPS_MIDI_GENERATED_MIDI_DEVICES_HPP");
  L.push("");
  L.push("#include <array>");
  L.push("#include <cstdint>");
  L.push("#include <span>");
  L.push("#include <string_view>");
  L.push("");
  L.push("namespace nisps::midi::generated {");
  L.push("");
  L.push("struct MidiParam {");
  L.push("    std::string_view id;");
  L.push("    std::string_view label;");
  L.push("    std::uint8_t cc;");
  L.push("    std::uint8_t min;");
  L.push("    std::uint8_t max;");
  L.push("    std::uint8_t default_value;");
  L.push("    std::string_view group;");
  L.push("};");
  L.push("");
  L.push("struct MidiDevice {");
  L.push("    std::string_view device_id;");
  L.push("    std::string_view name;");
  L.push("    std::string_view manufacturer;");
  L.push("    std::uint8_t default_channel;   // 1-16");
  L.push("    std::uint8_t value_min;");
  L.push("    std::uint8_t value_max;");
  L.push("    std::span<const MidiParam> params;");
  L.push("};");
  L.push("");

  for (const d of devices) {
    const pn = `k${toPascalCase(d.device_id)}Params`;
    L.push(`inline constexpr std::array<MidiParam, ${d.params.length}> ${pn} = {{`);
    for (const p of d.params) {
      L.push(`    MidiParam{${cppStringLit(p.id)}, ${cppStringLit(p.label)}, ${p.cc}, ${p.min}, ${p.max}, ${p.default}, ${cppStringLit(p.group)}},`);
    }
    L.push("}};");
    L.push("");
  }

  for (const d of devices) {
    const cn = `k${toPascalCase(d.device_id)}`;
    const pn = `${cn}Params`;
    L.push(`inline constexpr MidiDevice ${cn} = {`);
    L.push(`    ${cppStringLit(d.device_id)},`);
    L.push(`    ${cppStringLit(d.name)},`);
    L.push(`    ${cppStringLit(d.manufacturer)},`);
    L.push(`    ${d.midi.default_channel},`);
    L.push(`    ${d.midi.value_range[0]},`);
    L.push(`    ${d.midi.value_range[1]},`);
    L.push(`    std::span<const MidiParam>{${pn}},`);
    L.push("};");
    L.push("");
  }

  L.push(`inline constexpr std::size_t kMidiDeviceCount = ${devices.length}u;`);
  L.push(`inline constexpr std::array<MidiDevice, kMidiDeviceCount> kMidiDevices = {{`);
  for (const d of devices) {
    L.push(`    k${toPascalCase(d.device_id)},`);
  }
  L.push("}};");
  L.push("");
  L.push("}  // namespace nisps::midi::generated");
  L.push("");
  L.push("#endif  // NISPS_MIDI_GENERATED_MIDI_DEVICES_HPP");
  L.push("");
  return L.join("\n");
}

// ----- TS emission ----------------------------------------------------------

function emitTsTypes(): string {
  return [
    BANNER,
    "// Shared TypeScript types for generated MIDI device templates.",
    "",
    "export interface MidiDeviceParam {",
    "  readonly id: string;",
    "  readonly cc: number;",
    "  readonly label: string;",
    "  readonly min: number;",
    "  readonly max: number;",
    "  readonly default: number;",
    "  readonly group: string;",
    "}",
    "",
    "export interface MidiDeviceTemplate {",
    "  readonly device_id: string;",
    "  readonly name: string;",
    "  readonly manufacturer: string;",
    "  readonly year?: number;",
    "  readonly default_channel: number;",
    "  readonly value_min: number;",
    "  readonly value_max: number;",
    "  readonly params: readonly MidiDeviceParam[];",
    "}",
    "",
  ].join("\n");
}

function emitTsDevices(devices: DeviceSchema[]): string {
  const L: string[] = [];
  L.push(BANNER);
  L.push("import type { MidiDeviceTemplate } from './types';");
  L.push("");
  for (const d of devices) {
    const cn = `${toPascalCase(d.device_id)}Device`;
    L.push(`export const ${cn}: MidiDeviceTemplate = {`);
    L.push(`  device_id: ${tsStringLit(d.device_id)},`);
    L.push(`  name: ${tsStringLit(d.name)},`);
    L.push(`  manufacturer: ${tsStringLit(d.manufacturer)},`);
    if (d.year) L.push(`  year: ${d.year},`);
    L.push(`  default_channel: ${d.midi.default_channel},`);
    L.push(`  value_min: ${d.midi.value_range[0]},`);
    L.push(`  value_max: ${d.midi.value_range[1]},`);
    L.push("  params: [");
    for (const p of d.params) {
      L.push(`    { id: ${tsStringLit(p.id)}, cc: ${p.cc}, label: ${tsStringLit(p.label)}, min: ${p.min}, max: ${p.max}, default: ${p.default}, group: ${tsStringLit(p.group)} },`);
    }
    L.push("  ],");
    L.push("};");
    L.push("");
  }
  L.push("export const MIDI_DEVICES: readonly MidiDeviceTemplate[] = [");
  for (const d of devices) {
    L.push(`  ${toPascalCase(d.device_id)}Device,`);
  }
  L.push("];");
  L.push("");
  L.push("export const MIDI_DEVICES_BY_ID: Readonly<Record<string, MidiDeviceTemplate>> = {");
  for (const d of devices) {
    L.push(`  ${tsStringLit(d.device_id)}: ${toPascalCase(d.device_id)}Device,`);
  }
  L.push("};");
  L.push("");
  return L.join("\n");
}

function emitTsIndex(): string {
  return [BANNER, "", "export * from './types';", "export * from './devices';", ""].join("\n");
}

// ----- Driver ---------------------------------------------------------------

function main(): number {
  if (!existsSync(META_SCHEMA_PATH)) {
    console.error(`error: meta-schema not found at ${META_SCHEMA_PATH}`);
    return 1;
  }
  const metaSchema = readJSON<AnySchemaObject>(META_SCHEMA_PATH);
  const ajv = new Ajv2020({ strict: false, allErrors: true, allowUnionTypes: true });
  const validate = ajv.compile<DeviceSchema>(metaSchema);

  if (!existsSync(DEVICES_DIR)) {
    console.error(`error: devices directory not found at ${DEVICES_DIR}`);
    return 1;
  }
  const files = readdirSync(DEVICES_DIR).filter(f => f.endsWith(".json")).sort();
  if (files.length === 0) {
    console.error(`error: no device schemas in ${DEVICES_DIR}`);
    return 1;
  }

  const devices: DeviceSchema[] = [];
  let errors = 0;
  for (const f of files) {
    const path = join(DEVICES_DIR, f);
    let raw: unknown;
    try {
      raw = readJSON<unknown>(path);
    } catch (e) {
      console.error(`error: ${f}: parse: ${(e as Error).message}`);
      errors++;
      continue;
    }
    if (!validate(raw)) {
      console.error(`error: ${f}: schema validation failed:`);
      for (const err of validate.errors ?? []) {
        console.error(`  ${err.instancePath || "<root>"} ${err.message}`);
      }
      errors++;
      continue;
    }
    const d = raw as DeviceSchema;
    // uniqueness checks
    const ids = new Set<string>();
    for (const p of d.params) {
      if (ids.has(p.id)) {
        console.error(`error: ${f}: duplicate param id '${p.id}'`);
        errors++;
      }
      ids.add(p.id);
      if (p.min > p.max) {
        console.error(`error: ${f}: param '${p.id}' min>max`);
        errors++;
      }
    }
    devices.push(d);
  }
  if (errors > 0) {
    console.error(`\n${errors} error(s); aborting codegen.`);
    return 1;
  }
  devices.sort((a, b) => a.device_id.localeCompare(b.device_id));

  ensureDir(CPP_OUT_DIR);
  writeFileSync(join(CPP_OUT_DIR, "midi_devices.hpp"), emitCppHeader(devices));

  ensureDir(TS_OUT_DIR);
  writeFileSync(join(TS_OUT_DIR, "types.ts"), emitTsTypes());
  writeFileSync(join(TS_OUT_DIR, "devices.ts"), emitTsDevices(devices));
  writeFileSync(join(TS_OUT_DIR, "index.ts"), emitTsIndex());

  console.log(`OK  ${devices.length} MIDI device template(s) processed.`);
  console.log(`    C++ -> ${join(CPP_OUT_DIR, "midi_devices.hpp")}`);
  console.log(`    TS  -> ${TS_OUT_DIR}`);
  for (const d of devices) {
    console.log(`    - ${d.device_id}: ${d.params.length} params, default ch ${d.midi.default_channel}`);
  }
  return 0;
}

const isMain = (() => {
  if (typeof process === "undefined") return false;
  const argv1 = process.argv[1];
  if (!argv1) return false;
  return resolve(argv1) === fileURLToPath(import.meta.url);
})();
if (isMain) process.exit(main());

export { main };