import {
  existsSync,
  mkdirSync,
  readdirSync,
  readFileSync,
  writeFileSync,
} from "node:fs";
import { join } from "node:path";

type FinancialUnit = "currency" | "percent" | "ratio" | "shares" | "count";
type FinancialCadence = "annual" | "quarterly" | "ltm";
type FinancialStatementKind =
  | "income"
  | "balance"
  | "cash_flow"
  | "disclosure"
  | "equity"
  | "comprehensive_income";
type SignTransform = "invert" | "absolute";

type SurfaceDefinition = {
  surface_key: string;
  statement: FinancialStatementKind;
  label: string;
  category: string;
  order: number;
  unit: FinancialUnit;
  rollup_policy?: string;
  allowed_source_concepts: string[];
  allowed_authoritative_concepts?: string[];
  formula_fallback?:
    | {
        op: "sum" | "subtract" | "divide";
        sources: string[];
        treat_null_as_zero?: boolean;
      }
    | string
    | null;
  detail_grouping_policy?: string;
  materiality_policy?: string;
  include_in_output?: boolean;
  sign_transform?: "invert";
};

type SurfacePackFile = {
  version: string;
  pack: string;
  surfaces: SurfaceDefinition[];
};

type ComputationSpec =
  | { type: "ratio"; numerator: string; denominator: string }
  | { type: "yoy_growth"; source: string }
  | { type: "cagr"; source: string; years: number }
  | { type: "per_share"; source: string; shares_key: string }
  | { type: "simple"; formula: string };

type ComputedDefinition = {
  key: string;
  label: string;
  category: string;
  order: number;
  unit: FinancialUnit;
  computation: ComputationSpec;
  supported_cadences?: FinancialCadence[];
  requires_external_data?: string[];
};

type ComputedPackFile = {
  version: string;
  pack: string;
  computed: ComputedDefinition[];
};

type KpiDefinition = {
  key: string;
  label: string;
  unit: string;
};

type KpiPackFile = {
  version: string;
  pack: string;
  kpis: KpiDefinition[];
};

const TAXONOMY_DIR = join(process.cwd(), "rust", "taxonomy", "fiscal", "v1");
const OUTPUT_DIR = join(process.cwd(), "lib", "generated");

const PACK_ORDER = [
  "core",
  "bank_lender",
  "insurance",
  "reit_real_estate",
  "broker_asset_manager",
] as const;
type PackName = (typeof PACK_ORDER)[number];

function log(message: string) {
  console.log(`[generate-taxonomy] ${message}`);
}

function loadSurfacePacks(): Map<PackName, SurfacePackFile> {
  const packs = new Map<PackName, SurfacePackFile>();

  for (const pack of PACK_ORDER) {
    const path = join(TAXONOMY_DIR, `${pack}.surface.json`);
    if (!existsSync(path)) {
      continue;
    }

    const raw = readFileSync(path, "utf8");
    const file = JSON.parse(raw) as SurfacePackFile;
    packs.set(pack, file);
  }

  return packs;
}

function loadComputedPacks(): Map<PackName, ComputedPackFile> {
  const packs = new Map<PackName, ComputedPackFile>();

  for (const pack of PACK_ORDER) {
    const path = join(TAXONOMY_DIR, `${pack}.computed.json`);
    if (!existsSync(path)) {
      continue;
    }

    const raw = readFileSync(path, "utf8");
    const file = JSON.parse(raw) as ComputedPackFile;
    packs.set(pack, file);
  }

  return packs;
}

function loadKpiPacks(): Map<PackName, KpiPackFile> {
  const packs = new Map<PackName, KpiPackFile>();

  for (const pack of PACK_ORDER) {
    const path = join(TAXONOMY_DIR, "kpis", `${pack}.kpis.json`);
    if (!existsSync(path)) {
      continue;
    }

    const raw = readFileSync(path, "utf8");
    const file = JSON.parse(raw) as KpiPackFile;
    packs.set(pack, file);
  }

  return packs;
}

function validateSurfacePack(pack: SurfacePackFile, errors: string[]) {
  const keysByStatement = new Map<string, Set<string>>();

  for (const surface of pack.surfaces) {
    const keySet = keysByStatement.get(surface.statement) || new Set<string>();
    if (keySet.has(surface.surface_key)) {
      errors.push(
        `${pack.pack}: duplicate surface_key "${surface.surface_key}" in statement "${surface.statement}"`,
      );
    }
    keySet.add(surface.surface_key);
    keysByStatement.set(surface.statement, keySet);

    if (!surface.label) {
      errors.push(
        `${pack.pack}: surface "${surface.surface_key}" missing label`,
      );
    }

    const validStatements: FinancialStatementKind[] = [
      "income",
      "balance",
      "cash_flow",
      "disclosure",
      "equity",
      "comprehensive_income",
    ];
    if (!validStatements.includes(surface.statement)) {
      errors.push(
        `${pack.pack}: surface "${surface.surface_key}" has invalid statement "${surface.statement}"`,
      );
    }
  }
}

function validateComputedPack(
  pack: ComputedPackFile,
  surfaceKeys: Set<string>,
  errors: string[],
) {
  const keys = new Set<string>();

  for (const computed of pack.computed) {
    if (keys.has(computed.key)) {
      errors.push(`${pack.pack}: duplicate computed key "${computed.key}"`);
    }
    keys.add(computed.key);

    if (!computed.label) {
      errors.push(`${pack.pack}: computed "${computed.key}" missing label`);
    }

    const spec = computed.computation;
    switch (spec.type) {
      case "ratio":
        if (!surfaceKeys.has(spec.numerator) && !spec.numerator.includes("_")) {
          errors.push(
            `${pack.pack}: computed "${computed.key}" references unknown numerator "${spec.numerator}"`,
          );
        }
        if (
          !surfaceKeys.has(spec.denominator) &&
          !spec.denominator.includes("_")
        ) {
          errors.push(
            `${pack.pack}: computed "${computed.key}" references unknown denominator "${spec.denominator}"`,
          );
        }
        break;
      case "yoy_growth":
      case "cagr":
        if (!surfaceKeys.has(spec.source)) {
          errors.push(
            `${pack.pack}: computed "${computed.key}" references unknown source "${spec.source}"`,
          );
        }
        break;
      case "per_share":
        if (!surfaceKeys.has(spec.source)) {
          errors.push(
            `${pack.pack}: computed "${computed.key}" references unknown source "${spec.source}"`,
          );
        }
        if (!surfaceKeys.has(spec.shares_key)) {
          errors.push(
            `${pack.pack}: computed "${computed.key}" references unknown shares_key "${spec.shares_key}"`,
          );
        }
        break;
    }
  }
}

function generateTypesFile(): string {
  return `// Auto-generated by scripts/generate-taxonomy.ts
// DO NOT EDIT MANUALLY - changes will be overwritten

export type FinancialUnit = 'currency' | 'percent' | 'ratio' | 'shares' | 'count';

export type FinancialCadence = 'annual' | 'quarterly' | 'ltm';

export type FinancialStatementKind = 'income' | 'balance' | 'cash_flow' | 'disclosure' | 'equity' | 'comprehensive_income';

export type SignTransform = 'invert' | 'absolute';

export type ComputationSpec =
  | { type: 'ratio'; numerator: string; denominator: string }
  | { type: 'yoy_growth'; source: string }
  | { type: 'cagr'; source: string; years: number }
  | { type: 'per_share'; source: string; shares_key: string }
  | { type: 'simple'; formula: string };

export type SurfaceDefinition = {
  surface_key: string;
  statement: FinancialStatementKind;
  label: string;
  category: string;
  order: number;
  unit: FinancialUnit;
  rollup_policy?: string;
  allowed_source_concepts: string[];
  allowed_authoritative_concepts?: string[];
  formula_fallback?: {
    op: 'sum' | 'subtract' | 'divide';
    sources: string[];
    treat_null_as_zero?: boolean;
  } | string | null;
  detail_grouping_policy?: string;
  materiality_policy?: string;
  include_in_output?: boolean;
  sign_transform?: SignTransform;
};

export type ComputedDefinition = {
  key: string;
  label: string;
  category: string;
  order: number;
  unit: FinancialUnit;
  computation: ComputationSpec;
  supported_cadences?: FinancialCadence[];
  requires_external_data?: string[];
};

export type KpiDefinition = {
  key: string;
  label: string;
  unit: string;
};

export const RATIO_CATEGORIES = ['margins', 'returns', 'financial_health', 'per_share', 'growth', 'valuation'] as const;
export type RatioCategory = (typeof RATIO_CATEGORIES)[number];
`;
}

function generateSurfaceFile(
  statement: string,
  surfaces: SurfaceDefinition[],
): string {
  const sorted = [...surfaces].sort((a, b) => a.order - b.order);
  const constName = `${statement.toUpperCase()}_SURFACES`;

  return `// Auto-generated by scripts/generate-taxonomy.ts
// DO NOT EDIT MANUALLY - changes will be overwritten

import type { SurfaceDefinition } from '../types';

export const ${constName}: SurfaceDefinition[] = ${JSON.stringify(sorted, null, 2)};
`;
}

function generateSurfacesIndex(
  surfacesByStatement: Map<string, SurfaceDefinition[]>,
): string {
  const statements = [...surfacesByStatement.keys()].sort();

  const imports = statements
    .map((s) => `import { ${s.toUpperCase()}_SURFACES } from './${s}';`)
    .join("\n");

  const exports = statements
    .map((s) => `  ${s}: ${s.toUpperCase()}_SURFACES,`)
    .join("\n");

  return `// Auto-generated by scripts/generate-taxonomy.ts
// DO NOT EDIT MANUALLY - changes will be overwritten

${imports}

export const ALL_SURFACES_BY_STATEMENT = {
${exports}
} as const;

export { ${statements.map((s) => `${s.toUpperCase()}_SURFACES`).join(", ")} };
`;
}

function generateComputedFile(
  name: string,
  definitions: ComputedDefinition[],
): string {
  const sorted = [...definitions].sort((a, b) => a.order - b.order);
  const constName = name.toUpperCase().replace(/-/g, "_");

  return `// Auto-generated by scripts/generate-taxonomy.ts
// DO NOT EDIT MANUALLY - changes will be overwritten

import type { ComputedDefinition } from '../types';

export const ${constName}: ComputedDefinition[] = ${JSON.stringify(sorted, null, 2)};
`;
}

function generateComputedIndex(
  files: { name: string; definitions: ComputedDefinition[] }[],
): string {
  const imports = files
    .map((f) => {
      const constName = f.name.toUpperCase().replace(/-/g, "_");
      return `import { ${constName} } from './${f.name}';`;
    })
    .join("\n");

  const allExports = files
    .map((f) => `  ...${f.name.toUpperCase().replace(/-/g, "_")},`)
    .join("\n");

  const filingDerived = files
    .flatMap((f) => f.definitions)
    .filter(
      (d) => !d.requires_external_data || d.requires_external_data.length === 0,
    )
    .sort((a, b) => a.order - b.order);

  const marketDerived = files
    .flatMap((f) => f.definitions)
    .filter(
      (d) => d.requires_external_data && d.requires_external_data.length > 0,
    )
    .sort((a, b) => a.order - b.order);

  return `// Auto-generated by scripts/generate-taxonomy.ts
// DO NOT EDIT MANUALLY - changes will be overwritten

import type { ComputedDefinition } from '../types';

${imports}

export const ALL_COMPUTED: ComputedDefinition[] = [
${allExports}
];

export const FILING_DERIVED_COMPUTED: ComputedDefinition[] = ${JSON.stringify(filingDerived, null, 2)};

export const MARKET_DERIVED_COMPUTED: ComputedDefinition[] = ${JSON.stringify(marketDerived, null, 2)};

export { ${files.map((f) => f.name.toUpperCase().replace(/-/g, "_")).join(", ")} };
`;
}

function generateKpiFile(pack: string, kpis: KpiDefinition[]): string {
  const constName = `${pack.toUpperCase().replace(/-/g, "_")}_KPIS`;

  return `// Auto-generated by scripts/generate-taxonomy.ts
// DO NOT EDIT MANUALLY - changes will be overwritten

import type { KpiDefinition } from '../types';

export const ${constName}: KpiDefinition[] = ${JSON.stringify(kpis, null, 2)};
`;
}

function generateKpiIndex(
  packs: { pack: string; kpis: KpiDefinition[] }[],
): string {
  const imports = packs
    .map((p) => {
      const constName = p.pack.toUpperCase().replace(/-/g, "_");
      return `import { ${constName}_KPIS } from './${p.pack}';`;
    })
    .join("\n");

  const exports = packs
    .map((p) => `  ...${p.pack.toUpperCase().replace(/-/g, "_")}_KPIS,`)
    .join("\n");

  return `// Auto-generated by scripts/generate-taxonomy.ts
// DO NOT EDIT MANUALLY - changes will be overwritten

import type { KpiDefinition } from '../types';

${imports}

export const ALL_KPIS: KpiDefinition[] = [
${exports}
];

export { ${packs.map((p) => `${p.pack.toUpperCase().replace(/-/g, "_")}_KPIS`).join(", ")} };
`;
}

function generateMainIndex(): string {
  return `// Auto-generated by scripts/generate-taxonomy.ts
// DO NOT EDIT MANUALLY - changes will be overwritten

export type {
  FinancialUnit,
  FinancialCadence,
  FinancialStatementKind,
  ComputationSpec,
  SurfaceDefinition,
  ComputedDefinition,
  KpiDefinition,
} from './types';

export { RATIO_CATEGORIES, type RatioCategory } from './types';

export {
  INCOME_SURFACES,
  BALANCE_SURFACES,
  CASH_FLOW_SURFACES,
  ALL_SURFACES_BY_STATEMENT,
} from './surfaces';

export {
  ALL_COMPUTED,
  FILING_DERIVED_COMPUTED,
  MARKET_DERIVED_COMPUTED,
  CORE,
} from './computed';

export { ALL_KPIS, CORE_KPIS } from './kpis';
`;
}

async function main() {
  log("Loading taxonomy files...");

  const surfacePacks = loadSurfacePacks();
  const computedPacks = loadComputedPacks();
  const kpiPacks = loadKpiPacks();

  log(
    `Loaded ${surfacePacks.size} surface packs, ${computedPacks.size} computed packs, ${kpiPacks.size} KPI packs`,
  );

  const errors: string[] = [];

  log("Validating taxonomy files...");

  for (const [, pack] of surfacePacks) {
    validateSurfacePack(pack, errors);
  }

  const allSurfaceKeys = new Set<string>();
  for (const [, pack] of surfacePacks) {
    for (const surface of pack.surfaces) {
      allSurfaceKeys.add(surface.surface_key);
    }
  }

  for (const [, pack] of computedPacks) {
    validateComputedPack(pack, allSurfaceKeys, errors);
  }

  if (errors.length > 0) {
    console.error("Validation errors:");
    for (const error of errors) {
      console.error(`  - ${error}`);
    }
    process.exit(1);
  }

  log("Creating output directories...");
  mkdirSync(join(OUTPUT_DIR, "surfaces"), { recursive: true });
  mkdirSync(join(OUTPUT_DIR, "computed"), { recursive: true });
  mkdirSync(join(OUTPUT_DIR, "kpis"), { recursive: true });

  log("Generating types...");
  writeFileSync(join(OUTPUT_DIR, "types.ts"), generateTypesFile());

  log("Generating surfaces...");
  const coreSurfaces = surfacePacks.get("core");
  if (coreSurfaces) {
    const surfacesByStatement = new Map<string, SurfaceDefinition[]>();

    for (const surface of coreSurfaces.surfaces) {
      const existing = surfacesByStatement.get(surface.statement) || [];
      existing.push(surface);
      surfacesByStatement.set(surface.statement, existing);
    }

    for (const [statement, surfaces] of surfacesByStatement) {
      writeFileSync(
        join(OUTPUT_DIR, "surfaces", `${statement}.ts`),
        generateSurfaceFile(statement, surfaces),
      );
    }

    writeFileSync(
      join(OUTPUT_DIR, "surfaces", "index.ts"),
      generateSurfacesIndex(surfacesByStatement),
    );
  }

  log("Generating computed definitions...");
  const computedFiles: { name: string; definitions: ComputedDefinition[] }[] =
    [];

  for (const [pack, file] of computedPacks) {
    computedFiles.push({ name: pack, definitions: file.computed });
    writeFileSync(
      join(OUTPUT_DIR, "computed", `${pack}.ts`),
      generateComputedFile(pack, file.computed),
    );
  }

  writeFileSync(
    join(OUTPUT_DIR, "computed", "index.ts"),
    generateComputedIndex(computedFiles),
  );

  log("Generating KPI definitions...");
  const kpiFiles: { pack: string; kpis: KpiDefinition[] }[] = [];

  for (const [pack, file] of kpiPacks) {
    kpiFiles.push({ pack, kpis: file.kpis });
    writeFileSync(
      join(OUTPUT_DIR, "kpis", `${pack}.ts`),
      generateKpiFile(pack, file.kpis),
    );
  }

  writeFileSync(
    join(OUTPUT_DIR, "kpis", "index.ts"),
    generateKpiIndex(kpiFiles),
  );

  log("Generating main index...");
  writeFileSync(join(OUTPUT_DIR, "index.ts"), generateMainIndex());

  const surfaceCount = coreSurfaces?.surfaces.length || 0;
  const computedCount = computedFiles.reduce(
    (sum, f) => sum + f.definitions.length,
    0,
  );
  const kpiCount = kpiFiles.reduce((sum, f) => sum + f.kpis.length, 0);

  log(
    `Generated ${surfaceCount} surfaces, ${computedCount} computed definitions, ${kpiCount} KPIs`,
  );
  log(`Output written to ${OUTPUT_DIR}`);
}

main().catch((error) => {
  console.error("Generation failed:", error);
  process.exit(1);
});