// TypeScript port of posthog/hogql/context.py
// Adapted for ClickHouse client's {param: Type} syntax

import { getClickHouseType } from "./escape";
import { SchemaRegistry, FieldMappings } from "./schema";

/**
 * Settings that control query execution behavior
 */
export interface QuerySettings {
  /** Maximum number of rows to return */
  maxRows?: number;
  /** Timezone for date/time operations */
  timezone?: string;
  /** Whether to allow full table scans */
  allowFullTableScans?: boolean;
  /** Query timeout in seconds */
  timeoutSeconds?: number;
}

/**
 * A simple comparison condition (e.g., column > value)
 */
export interface SimpleComparisonCondition {
  /** The comparison operator */
  op: "eq" | "neq" | "gt" | "gte" | "lt" | "lte";
  /** The value to compare against */
  value: Date | string | number;
}

/**
 * A between condition (e.g., column BETWEEN low AND high)
 */
export interface BetweenCondition {
  /** The between operator */
  op: "between";
  /** The low bound of the range */
  low: Date | string | number;
  /** The high bound of the range */
  high: Date | string | number;
}

/**
 * An IN condition (e.g., column IN ('a', 'b', 'c'))
 */
export interface InCondition {
  /** The in operator */
  op: "in";
  /** The values to check against */
  values: (string | number)[];
}

/**
 * A WHERE clause condition that can be either a simple comparison, a BETWEEN, or an IN.
 * Used for both enforcedWhereClause (always applied) and whereClauseFallback (default when user doesn't filter).
 */
export type WhereClauseCondition = SimpleComparisonCondition | BetweenCondition | InCondition;

/**
 * A time range used by `timeBucket()` to determine the appropriate bucket interval.
 */
export interface TimeRange {
  /** Start of the time range (inclusive) */
  from: Date;
  /** End of the time range (inclusive) */
  to: Date;
}

/**
 * Default query settings
 */
export const DEFAULT_QUERY_SETTINGS: Required<QuerySettings> = {
  maxRows: 10000,
  timezone: "UTC",
  allowFullTableScans: false,
  timeoutSeconds: 60,
};

/**
 * A warning or notice collected during query printing
 */
export interface QueryNotice {
  code: string;
  message: string;
  start?: number;
  end?: number;
}

/**
 * Context for the TSQL to ClickHouse printer
 *
 * Holds:
 * - Enforced WHERE conditions for tenant isolation and plan limits
 * - Schema registry for table/column validation
 * - Parameter accumulator for SQL injection safety
 * - Query settings and execution options
 * - Field mappings for runtime value translation
 */
export class PrinterContext {
  /** Accumulated parameter values for parameterized query */
  private values: Record<string, unknown> = {};

  /** Counter for generating unique parameter names */
  private paramCounter = 0;

  /** Warnings collected during printing */
  readonly warnings: QueryNotice[] = [];

  /** Errors collected during printing */
  readonly errors: QueryNotice[] = [];

  /** Runtime field mappings for dynamic value translation */
  readonly fieldMappings: FieldMappings;

  /**
   * Enforced WHERE conditions that are ALWAYS applied at the table level.
   * Used for tenant isolation (org_id, project_id, env_id) and plan-based limits.
   * Applied to every table reference including subqueries, CTEs, and JOINs.
   */
  readonly enforcedWhereClause: Record<string, WhereClauseCondition>;

  /**
   * Time range for `timeBucket()` interval calculation.
   * When provided, `timeBucket()` uses this to determine the appropriate bucket size.
   */
  readonly timeRange?: TimeRange;

  constructor(
    /** Schema registry containing allowed tables and columns */
    public readonly schema: SchemaRegistry,
    /** Query execution settings */
    public readonly settings: QuerySettings = {},
    /** Runtime field mappings for dynamic value translation */
    fieldMappings: FieldMappings = {},
    /**
     * Enforced WHERE conditions that are ALWAYS applied at the table level.
     * Must include tenant columns (e.g., organization_id) for multi-tenant tables.
     */
    enforcedWhereClause: Record<string, WhereClauseCondition> = {},
    /** Time range for timeBucket() interval calculation */
    timeRange?: TimeRange
  ) {
    // Initialize with default settings
    this.settings = { ...DEFAULT_QUERY_SETTINGS, ...settings };
    this.fieldMappings = fieldMappings;
    this.enforcedWhereClause = enforcedWhereClause;
    this.timeRange = timeRange;
  }

  /**
   * Get the timezone setting
   */
  get timezone(): string {
    return this.settings.timezone ?? DEFAULT_QUERY_SETTINGS.timezone;
  }

  /**
   * Get the max rows setting
   */
  get maxRows(): number {
    return this.settings.maxRows ?? DEFAULT_QUERY_SETTINGS.maxRows;
  }

  /**
   * Add a value to the parameter map and return a ClickHouse placeholder
   *
   * @param value The value to parameterize
   * @returns A placeholder string like "{tsql_val_0: String}"
   */
  addValue(value: unknown): string {
    const key = `tsql_val_${this.paramCounter++}`;
    this.values[key] = value;
    const chType = getClickHouseType(value);
    return `{${key}: ${chType}}`;
  }

  /**
   * Add a value with a specific key (for named parameters)
   *
   * @param key The parameter name
   * @param value The value
   * @returns A placeholder string like "{key: Type}"
   */
  addNamedValue(key: string, value: unknown): string {
    this.values[key] = value;
    const chType = getClickHouseType(value);
    return `{${key}: ${chType}}`;
  }

  /**
   * Get all accumulated parameter values
   */
  getParams(): Record<string, unknown> {
    return { ...this.values };
  }

  /**
   * Add a warning notice
   */
  addWarning(code: string, message: string, start?: number, end?: number): void {
    this.warnings.push({ code, message, start, end });
  }

  /**
   * Add an error notice
   */
  addError(code: string, message: string, start?: number, end?: number): void {
    this.errors.push({ code, message, start, end });
  }

  /**
   * Check if any errors were collected
   */
  hasErrors(): boolean {
    return this.errors.length > 0;
  }

  /**
   * Create a child context that shares the same parameter accumulator
   * Useful for handling subqueries while keeping parameters unified
   */
  createChildContext(): PrinterContext {
    const child = new PrinterContext(
      this.schema,
      this.settings,
      this.fieldMappings,
      this.enforcedWhereClause,
      this.timeRange
    );
    // Share the same values map so parameters are unified
    child.values = this.values;
    // Share the same counter reference via closure
    const parentThis = this;
    Object.defineProperty(child, "paramCounter", {
      get() {
        return parentThis.paramCounter;
      },
      set(v: number) {
        parentThis.paramCounter = v;
      },
    });
    return child;
  }
}

/**
 * Options for creating a printer context
 */
export interface PrinterContextOptions {
  /** Schema registry containing allowed tables and columns */
  schema: SchemaRegistry;
  /** Query execution settings */
  settings?: QuerySettings;
  /**
   * Runtime field mappings for dynamic value translation.
   * Maps internal ClickHouse values to external user-facing values.
   */
  fieldMappings?: FieldMappings;
  /**
   * REQUIRED: Conditions always applied at the table level.
   * Must include tenant columns (e.g., organization_id) for multi-tenant tables.
   * Applied to every table reference including subqueries, CTEs, and JOINs.
   *
   * @example
   * ```typescript
   * {
   *   organization_id: { op: "eq", value: "org_123" },
   *   project_id: { op: "eq", value: "proj_456" },
   *   triggered_at: { op: "gte", value: new Date(Date.now() - 7 * 24 * 60 * 60 * 1000) }
   * }
   * ```
   */
  enforcedWhereClause: Record<string, WhereClauseCondition>;
  /**
   * Time range for `timeBucket()` interval calculation.
   * When provided, `timeBucket()` uses this to determine the appropriate bucket size.
   */
  timeRange?: TimeRange;
}

/**
 * Create a new PrinterContext
 */
export function createPrinterContext(options: PrinterContextOptions): PrinterContext {
  return new PrinterContext(
    options.schema,
    options.settings,
    options.fieldMappings,
    options.enforcedWhereClause,
    options.timeRange
  );
}
