import type { ColumnInfo, DatabaseType } from "@/types/database";
import { metricRangeQuery, qualifiedTableName, quoteTableDataIdentifier } from "@/lib/table/tableSelectSql";

export interface TableSqlTemplateOptions {
  databaseType?: DatabaseType;
  driverProfile?: string;
  identifierQuote?: string;
  schema?: string;
  catalog?: string;
  database?: string;
  includeDatabaseName?: boolean;
  tableName: string;
  columns?: ColumnInfo[];
  tableType?: string;
}

export function buildTableSelectTemplate(options: TableSqlTemplateOptions): string {
  if (options.databaseType === "victoriametrics") return metricRangeQuery(options.tableName);
  const tableName = templateTableName(options);
  const columns = options.columns ?? [];
  if (!columns.length) {
    return `SELECT *\nFROM ${tableName};`;
  }
  const selectColumns = columns.map((column) => templateIdentifier(options, column.name));
  return `SELECT ${selectColumns.join(", ")}\nFROM ${tableName};`;
}

export function buildTableInsertTemplate(options: TableSqlTemplateOptions): string {
  const strategy = options.databaseType ? insertTemplateStrategies[options.databaseType] : undefined;
  return (strategy ?? buildDefaultInsertTemplate)(options);
}

type InsertTemplateStrategy = (options: TableSqlTemplateOptions) => string;

function buildDefaultInsertTemplate(options: TableSqlTemplateOptions): string {
  const tableName = templateTableName(options);
  const columns = (options.columns ?? []).filter((column) => !isAutoGeneratedColumn(column));

  // TDengine does not support INSERT INTO t(col1, col2) VALUES(...) syntax
  if (options.databaseType === "tdengine") {
    const values = columns.map((column) => columnPlaceholderValue(column, options.databaseType));
    if (!values.length) {
      return `INSERT INTO ${tableName}\nVALUES (/* TODO: add values */);`;
    }
    return `INSERT INTO ${tableName}\nVALUES (${values.join(", ")});`;
  }

  if (!columns.length) {
    return `INSERT INTO ${tableName}\n/* TODO: add column values */\nVALUES ();`;
  }

  const columnNames = columns.map((column) => templateIdentifier(options, column.name));
  const values = columns.map((column) => columnPlaceholderValue(column, options.databaseType));
  return `INSERT INTO ${tableName} (${columnNames.join(", ")})\nVALUES (${values.join(", ")});`;
}

function buildTdengineInsertTemplate(options: TableSqlTemplateOptions): string {
  const columns = options.columns ?? [];
  const isTagColumn = (column: ColumnInfo) => (column.comment ?? "").toUpperCase() === "TAG" || (column.extra ?? "").toUpperCase().includes("TAG");
  const tagColumns = columns.filter((column) => isTagColumn(column));
  const normalizedTableType = (options.tableType ?? "").toUpperCase();
  const shouldUseStableTemplate = normalizedTableType === "STABLE" || (!normalizedTableType && tagColumns.length > 0);

  if (!shouldUseStableTemplate) {
    return buildDefaultInsertTemplate(options);
  }

  const valueColumns = columns.filter((column) => !isTagColumn(column)).filter((column) => !isAutoGeneratedColumn(column));
  const tagPlaceholders = tagColumns.map((column) => columnPlaceholderValue(column, options.databaseType));
  const tagsSql = tagPlaceholders.length > 0 ? `TAGS (${tagPlaceholders.join(", ")})` : "TAGS (/* TODO: add tag values */)";
  const stableNameForUsing = templateTableName(options).replace(/^`|`$/g, "");
  const valuePlaceholders = valueColumns.map((column) => columnPlaceholderValue(column, options.databaseType));

  if (!valueColumns.length) {
    return `INSERT INTO /* child_table_name */ USING ${stableNameForUsing}\n${tagsSql}\nVALUES (/* TODO: add values */);`;
  }

  return `INSERT INTO /* child_table_name */ USING ${stableNameForUsing}\n${tagsSql}\nVALUES (${valuePlaceholders.join(", ")});`;
}

const insertTemplateStrategies: Partial<Record<DatabaseType, InsertTemplateStrategy>> = {
  tdengine: buildTdengineInsertTemplate,
};

export function buildTableUpdateTemplate(options: TableSqlTemplateOptions): string {
  const tableName = templateTableName(options);
  const columns = options.columns ?? [];
  const primaryKeys = columns.filter((column) => column.is_primary_key);
  const primaryKeyNames = new Set(primaryKeys.map((column) => column.name));
  const updateColumns = columns.filter((column) => !primaryKeyNames.has(column.name));
  const setClause = updateColumns.length ? updateColumns.map((column) => `${templateIdentifier(options, column.name)} = ${columnPlaceholderValue(column, options.databaseType)}`).join(",\n    ") : "/* TODO: set column = value */";

  return `UPDATE ${tableName}\nSET ${setClause}\n${buildWhereClause(options, primaryKeys)};`;
}

export function buildTableDeleteTemplate(options: TableSqlTemplateOptions): string {
  const tableName = templateTableName(options);
  const primaryKeys = (options.columns ?? []).filter((column) => column.is_primary_key);
  return `DELETE FROM ${tableName}\n${buildWhereClause(options, primaryKeys)};`;
}

function templateTableName(options: TableSqlTemplateOptions): string {
  return qualifiedTableName({
    databaseType: options.databaseType,
    driverProfile: options.driverProfile,
    identifierQuote: options.identifierQuote,
    catalog: options.catalog,
    database: options.database,
    includeDatabaseName: options.includeDatabaseName,
    schema: options.schema,
    tableName: options.tableName,
  });
}

function templateIdentifier(options: TableSqlTemplateOptions, name: string): string {
  return quoteTableDataIdentifier(options.databaseType, name, options.identifierQuote);
}

function buildWhereClause(options: TableSqlTemplateOptions, primaryKeys: ColumnInfo[]): string {
  if (!primaryKeys.length) return "WHERE /* TODO: add WHERE clause */";
  const conditions = primaryKeys.map((column) => `${templateIdentifier(options, column.name)} = ${columnPlaceholderValue(column, options.databaseType)}`);
  return `WHERE ${conditions.join(" AND ")}`;
}

function isAutoGeneratedColumn(column: ColumnInfo): boolean {
  const extra = (column.extra ?? "").toLowerCase().trim();
  const colDefault = (column.column_default ?? "").toLowerCase().trim();
  const dataType = (column.data_type ?? "").trim();

  if (typeLooksPostgresTextSearchVector(dataType)) return true;
  if (extra.includes("auto_increment")) return true;
  if (extra.includes("autoincrement")) return true;
  if (extra.includes("identity")) return true;
  if (extra.includes("generated") && (extra.includes("as identity") || extra.includes("always as"))) return true;
  if (colDefault.includes("nextval(")) return true;
  if (colDefault.includes(".nextval")) return true;
  if ((extra.includes("virtual") || extra.includes("computed")) && extra.includes("generated")) return true;

  return false;
}

function columnPlaceholderValue(column: ColumnInfo, databaseType?: DatabaseType): string {
  const dataType = (column.data_type ?? "").trim();
  const colName = column.name;

  if (typeLooksNumeric(dataType)) return "0";
  if (typeLooksBoolean(dataType)) return databaseType === "mysql" || databaseType === "sqlite" || databaseType === "rqlite" || databaseType === "cloudflare-d1" ? "1" : "TRUE";
  if (typeLooksDateOnly(dataType)) return "'2024-01-01'";
  if (typeLooksTimeOnly(dataType)) return "'12:00:00'";
  if (typeLooksTimestamp(dataType)) return databaseType === "tdengine" ? "NOW" : "CURRENT_TIMESTAMP";
  if (typeLooksJson(dataType)) return databaseType === "postgres" || databaseType === "redshift" ? "'{}'::jsonb" : "'{}'";
  if (typeLooksBinary(dataType)) return "''";
  if (typeLooksUuid(dataType)) return databaseType === "postgres" || databaseType === "redshift" ? "'00000000-0000-0000-0000-000000000000'::uuid" : "'00000000-0000-0000-0000-000000000000'";
  if (typeLooksXml(dataType)) return "'<root/>'";
  if (typeLooksSpatial(dataType)) return "NULL";
  if (typeLooksArray(dataType)) return "'{}'";

  return `'${colName}_value'`;
}

function typeLooksNumeric(dataType: string): boolean {
  return /^(tinyint|smallint|mediumint|int\d*|integer\d*|bigint|smallserial|serial\d*|bigserial|number|numeric|decimal|dec|float\d*|double|real|double\s+precision|money|smallmoney|fixed)/i.test(dataType.trim());
}

function typeLooksBoolean(dataType: string): boolean {
  return /^(bool|boolean|bit\s*\(\s*1\s*\))$/i.test(dataType.trim());
}

function typeLooksDateOnly(dataType: string): boolean {
  return /^date$/i.test(dataType.trim());
}

function typeLooksTimeOnly(dataType: string): boolean {
  return /^time\b(?!stamp|stamptz|with|without)/i.test(dataType.trim());
}

function typeLooksTimestamp(dataType: string): boolean {
  return /^(datetime|timestamp|timestamptz|timestamp\s+with\s+time\s+zone|timestamp\s+without\s+time\s+zone|smalldatetime|datetime2|datetimeoffset)/i.test(dataType.trim());
}

function typeLooksJson(dataType: string): boolean {
  return /^(json|jsonb)$/i.test(dataType.trim());
}

function typeLooksBinary(dataType: string): boolean {
  return /^(bytea|blob|binary|varbinary|image|raw|longblob|mediumblob|tinyblob|long\s+raw|bfile)$/i.test(dataType.trim());
}

function typeLooksUuid(dataType: string): boolean {
  return /^uuid$/i.test(dataType.trim());
}

function typeLooksXml(dataType: string): boolean {
  return /^xml$/i.test(dataType.trim());
}

function typeLooksSpatial(dataType: string): boolean {
  return /^(geometry|geography|point|polygon|linestring|box|circle|path|line|lseg)/i.test(dataType.trim());
}

function typeLooksArray(dataType: string): boolean {
  return /^(array|vector|_float\d*|_int\d*|_text|_varchar|_bool|_uuid)/i.test(dataType.trim());
}

function typeLooksPostgresTextSearchVector(dataType: string): boolean {
  const normalized = dataType
    .trim()
    .replace(/^"+|"+$/g, "")
    .toLowerCase();
  return normalized === "tsvector" || normalized.endsWith(".tsvector");
}