package inspector

import (
	"regexp"
	"strings"

	"git.warky.dev/wdevs/relspecgo/pkg/models"
	"git.warky.dev/wdevs/relspecgo/pkg/pgsql"
)

// validatePrimaryKeyNaming checks that primary key column names match a pattern
func validatePrimaryKeyNaming(db *models.Database, rule Rule, ruleName string) []ValidationResult {
	results := []ValidationResult{}
	pattern, err := regexp.Compile(rule.Pattern)
	if err != nil {
		return results
	}

	for _, schema := range db.Schemas {
		for _, table := range schema.Tables {
			for _, col := range table.Columns {
				if col.IsPrimaryKey {
					location := formatLocation(schema.Name, table.Name, col.Name)
					passed := pattern.MatchString(col.Name)

					results = append(results, createResult(
						ruleName,
						passed,
						rule.Message,
						location,
						map[string]interface{}{
							"schema":           schema.Name,
							"table":            table.Name,
							"column":           col.Name,
							"expected_pattern": rule.Pattern,
						},
					))
				}
			}
		}
	}

	return results
}

// validatePrimaryKeyDatatype checks that primary keys use approved data types
func validatePrimaryKeyDatatype(db *models.Database, rule Rule, ruleName string) []ValidationResult {
	results := []ValidationResult{}

	for _, schema := range db.Schemas {
		for _, table := range schema.Tables {
			for _, col := range table.Columns {
				if col.IsPrimaryKey {
					location := formatLocation(schema.Name, table.Name, col.Name)

					// Normalize type (remove size/precision)
					normalizedType := normalizeDataType(col.Type)
					passed := contains(rule.AllowedTypes, normalizedType)

					results = append(results, createResult(
						ruleName,
						passed,
						rule.Message,
						location,
						map[string]interface{}{
							"schema":        schema.Name,
							"table":         table.Name,
							"column":        col.Name,
							"current_type":  col.Type,
							"allowed_types": rule.AllowedTypes,
						},
					))
				}
			}
		}
	}

	return results
}

// validatePrimaryKeyAutoIncrement checks primary key auto-increment settings
func validatePrimaryKeyAutoIncrement(db *models.Database, rule Rule, ruleName string) []ValidationResult {
	results := []ValidationResult{}

	for _, schema := range db.Schemas {
		for _, table := range schema.Tables {
			for _, col := range table.Columns {
				if col.IsPrimaryKey {
					location := formatLocation(schema.Name, table.Name, col.Name)

					// Check if auto-increment matches requirement
					passed := col.AutoIncrement == rule.RequireAutoIncrement

					if !passed {
						results = append(results, createResult(
							ruleName,
							false,
							rule.Message,
							location,
							map[string]interface{}{
								"schema":                 schema.Name,
								"table":                  table.Name,
								"column":                 col.Name,
								"has_auto_increment":     col.AutoIncrement,
								"require_auto_increment": rule.RequireAutoIncrement,
							},
						))
					}
				}
			}
		}
	}

	return results
}

// validateForeignKeyColumnNaming checks that foreign key column names match a pattern
func validateForeignKeyColumnNaming(db *models.Database, rule Rule, ruleName string) []ValidationResult {
	results := []ValidationResult{}
	pattern, err := regexp.Compile(rule.Pattern)
	if err != nil {
		return results
	}

	for _, schema := range db.Schemas {
		for _, table := range schema.Tables {
			// Check foreign key constraints
			for _, constraint := range table.Constraints {
				if constraint.Type == models.ForeignKeyConstraint {
					for _, colName := range constraint.Columns {
						location := formatLocation(schema.Name, table.Name, colName)
						passed := pattern.MatchString(colName)

						results = append(results, createResult(
							ruleName,
							passed,
							rule.Message,
							location,
							map[string]interface{}{
								"schema":           schema.Name,
								"table":            table.Name,
								"column":           colName,
								"constraint":       constraint.Name,
								"expected_pattern": rule.Pattern,
							},
						))
					}
				}
			}
		}
	}

	return results
}

// validateForeignKeyConstraintNaming checks that foreign key constraint names match a pattern
func validateForeignKeyConstraintNaming(db *models.Database, rule Rule, ruleName string) []ValidationResult {
	results := []ValidationResult{}
	pattern, err := regexp.Compile(rule.Pattern)
	if err != nil {
		return results
	}

	for _, schema := range db.Schemas {
		for _, table := range schema.Tables {
			for _, constraint := range table.Constraints {
				if constraint.Type == models.ForeignKeyConstraint {
					location := formatLocation(schema.Name, table.Name, "")
					passed := pattern.MatchString(constraint.Name)

					results = append(results, createResult(
						ruleName,
						passed,
						rule.Message,
						location,
						map[string]interface{}{
							"schema":           schema.Name,
							"table":            table.Name,
							"constraint":       constraint.Name,
							"expected_pattern": rule.Pattern,
						},
					))
				}
			}
		}
	}

	return results
}

// validateForeignKeyIndex checks that foreign key columns have indexes
func validateForeignKeyIndex(db *models.Database, rule Rule, ruleName string) []ValidationResult {
	results := []ValidationResult{}

	if !rule.RequireIndex {
		return results
	}

	for _, schema := range db.Schemas {
		for _, table := range schema.Tables {
			// Get all foreign key columns
			fkColumns := make(map[string]bool)
			for _, constraint := range table.Constraints {
				if constraint.Type == models.ForeignKeyConstraint {
					for _, col := range constraint.Columns {
						fkColumns[col] = true
					}
				}
			}

			// Check if each FK column has an index
			for fkCol := range fkColumns {
				hasIndex := false

				// Check table indexes
				for _, index := range table.Indexes {
					// Index is good if FK column is the first column
					if len(index.Columns) > 0 && index.Columns[0] == fkCol {
						hasIndex = true
						break
					}
				}

				location := formatLocation(schema.Name, table.Name, fkCol)
				results = append(results, createResult(
					ruleName,
					hasIndex,
					rule.Message,
					location,
					map[string]interface{}{
						"schema":    schema.Name,
						"table":     table.Name,
						"column":    fkCol,
						"has_index": hasIndex,
					},
				))
			}
		}
	}

	return results
}

// validateTableNamingCase checks table name casing
func validateTableNamingCase(db *models.Database, rule Rule, ruleName string) []ValidationResult {
	results := []ValidationResult{}
	pattern, err := regexp.Compile(rule.Pattern)
	if err != nil {
		return results
	}

	for _, schema := range db.Schemas {
		for _, table := range schema.Tables {
			location := formatLocation(schema.Name, table.Name, "")
			passed := pattern.MatchString(table.Name)

			results = append(results, createResult(
				ruleName,
				passed,
				rule.Message,
				location,
				map[string]interface{}{
					"schema":           schema.Name,
					"table":            table.Name,
					"expected_case":    rule.Case,
					"expected_pattern": rule.Pattern,
				},
			))
		}
	}

	return results
}

// validateColumnNamingCase checks column name casing
func validateColumnNamingCase(db *models.Database, rule Rule, ruleName string) []ValidationResult {
	results := []ValidationResult{}
	pattern, err := regexp.Compile(rule.Pattern)
	if err != nil {
		return results
	}

	for _, schema := range db.Schemas {
		for _, table := range schema.Tables {
			for _, col := range table.Columns {
				location := formatLocation(schema.Name, table.Name, col.Name)
				passed := pattern.MatchString(col.Name)

				results = append(results, createResult(
					ruleName,
					passed,
					rule.Message,
					location,
					map[string]interface{}{
						"schema":           schema.Name,
						"table":            table.Name,
						"column":           col.Name,
						"expected_case":    rule.Case,
						"expected_pattern": rule.Pattern,
					},
				))
			}
		}
	}

	return results
}

// validateTableNameLength checks table name length
func validateTableNameLength(db *models.Database, rule Rule, ruleName string) []ValidationResult {
	results := []ValidationResult{}

	for _, schema := range db.Schemas {
		for _, table := range schema.Tables {
			location := formatLocation(schema.Name, table.Name, "")
			passed := len(table.Name) <= rule.MaxLength

			results = append(results, createResult(
				ruleName,
				passed,
				rule.Message,
				location,
				map[string]interface{}{
					"schema":     schema.Name,
					"table":      table.Name,
					"length":     len(table.Name),
					"max_length": rule.MaxLength,
				},
			))
		}
	}

	return results
}

// validateColumnNameLength checks column name length
func validateColumnNameLength(db *models.Database, rule Rule, ruleName string) []ValidationResult {
	results := []ValidationResult{}

	for _, schema := range db.Schemas {
		for _, table := range schema.Tables {
			for _, col := range table.Columns {
				location := formatLocation(schema.Name, table.Name, col.Name)
				passed := len(col.Name) <= rule.MaxLength

				results = append(results, createResult(
					ruleName,
					passed,
					rule.Message,
					location,
					map[string]interface{}{
						"schema":     schema.Name,
						"table":      table.Name,
						"column":     col.Name,
						"length":     len(col.Name),
						"max_length": rule.MaxLength,
					},
				))
			}
		}
	}

	return results
}

// validateReservedKeywords checks for reserved SQL keywords
func validateReservedKeywords(db *models.Database, rule Rule, ruleName string) []ValidationResult {
	results := []ValidationResult{}

	// Build keyword map from PostgreSQL keywords
	keywordSlice := pgsql.GetPostgresKeywords()
	keywords := make(map[string]bool)
	for _, kw := range keywordSlice {
		keywords[strings.ToUpper(kw)] = true
	}

	for _, schema := range db.Schemas {
		for _, table := range schema.Tables {
			// Check table name
			if rule.CheckTables {
				location := formatLocation(schema.Name, table.Name, "")
				passed := !keywords[strings.ToUpper(table.Name)]

				results = append(results, createResult(
					ruleName,
					passed,
					rule.Message,
					location,
					map[string]interface{}{
						"schema":      schema.Name,
						"table":       table.Name,
						"object_type": "table",
					},
				))
			}

			// Check column names
			if rule.CheckColumns {
				for _, col := range table.Columns {
					location := formatLocation(schema.Name, table.Name, col.Name)
					passed := !keywords[strings.ToUpper(col.Name)]

					results = append(results, createResult(
						ruleName,
						passed,
						rule.Message,
						location,
						map[string]interface{}{
							"schema":      schema.Name,
							"table":       table.Name,
							"column":      col.Name,
							"object_type": "column",
						},
					))
				}
			}
		}
	}

	return results
}

// validateMissingPrimaryKey checks for tables without primary keys
func validateMissingPrimaryKey(db *models.Database, rule Rule, ruleName string) []ValidationResult {
	results := []ValidationResult{}

	for _, schema := range db.Schemas {
		for _, table := range schema.Tables {
			hasPrimaryKey := false

			// Check columns for primary key
			for _, col := range table.Columns {
				if col.IsPrimaryKey {
					hasPrimaryKey = true
					break
				}
			}

			// Also check constraints
			if !hasPrimaryKey {
				for _, constraint := range table.Constraints {
					if constraint.Type == models.PrimaryKeyConstraint {
						hasPrimaryKey = true
						break
					}
				}
			}

			location := formatLocation(schema.Name, table.Name, "")
			results = append(results, createResult(
				ruleName,
				hasPrimaryKey,
				rule.Message,
				location,
				map[string]interface{}{
					"schema": schema.Name,
					"table":  table.Name,
				},
			))
		}
	}

	return results
}

// validateOrphanedForeignKey checks for foreign keys referencing non-existent tables
func validateOrphanedForeignKey(db *models.Database, rule Rule, ruleName string) []ValidationResult {
	results := []ValidationResult{}

	// Build a map of existing tables for quick lookup
	tableExists := make(map[string]bool)
	for _, schema := range db.Schemas {
		for _, table := range schema.Tables {
			key := schema.Name + "." + table.Name
			tableExists[key] = true
		}
	}

	// Check all foreign key constraints
	for _, schema := range db.Schemas {
		for _, table := range schema.Tables {
			for _, constraint := range table.Constraints {
				if constraint.Type == models.ForeignKeyConstraint {
					// Build referenced table key
					refSchema := constraint.ReferencedSchema
					if refSchema == "" {
						refSchema = schema.Name
					}
					refKey := refSchema + "." + constraint.ReferencedTable

					location := formatLocation(schema.Name, table.Name, "")
					passed := tableExists[refKey]

					results = append(results, createResult(
						ruleName,
						passed,
						rule.Message,
						location,
						map[string]interface{}{
							"schema":            schema.Name,
							"table":             table.Name,
							"constraint":        constraint.Name,
							"referenced_schema": refSchema,
							"referenced_table":  constraint.ReferencedTable,
						},
					))
				}
			}
		}
	}

	return results
}

// validateCircularDependency checks for circular foreign key dependencies
func validateCircularDependency(db *models.Database, rule Rule, ruleName string) []ValidationResult {
	results := []ValidationResult{}

	// Build dependency graph
	dependencies := make(map[string][]string)
	for _, schema := range db.Schemas {
		for _, table := range schema.Tables {
			tableKey := schema.Name + "." + table.Name

			for _, constraint := range table.Constraints {
				if constraint.Type == models.ForeignKeyConstraint {
					refSchema := constraint.ReferencedSchema
					if refSchema == "" {
						refSchema = schema.Name
					}
					refKey := refSchema + "." + constraint.ReferencedTable

					dependencies[tableKey] = append(dependencies[tableKey], refKey)
				}
			}
		}
	}

	// Check for cycles using DFS
	for tableKey := range dependencies {
		visited := make(map[string]bool)
		recStack := make(map[string]bool)

		if hasCycle(tableKey, dependencies, visited, recStack) {
			parts := strings.Split(tableKey, ".")
			location := formatLocation(parts[0], parts[1], "")

			results = append(results, createResult(
				ruleName,
				false,
				rule.Message,
				location,
				map[string]interface{}{
					"schema": parts[0],
					"table":  parts[1],
				},
			))
		}
	}

	return results
}

// Helper functions

// hasCycle performs DFS to detect cycles in dependency graph
func hasCycle(node string, graph map[string][]string, visited, recStack map[string]bool) bool {
	visited[node] = true
	recStack[node] = true

	for _, neighbor := range graph[node] {
		if !visited[neighbor] {
			if hasCycle(neighbor, graph, visited, recStack) {
				return true
			}
		} else if recStack[neighbor] {
			return true
		}
	}

	recStack[node] = false
	return false
}

// normalizeDataType removes size/precision from data type
func normalizeDataType(dataType string) string {
	// Remove everything in parentheses
	idx := strings.Index(dataType, "(")
	if idx > 0 {
		dataType = dataType[:idx]
	}
	return strings.ToLower(strings.TrimSpace(dataType))
}

// contains checks if a string slice contains a value
func contains(slice []string, value string) bool {
	for _, item := range slice {
		if strings.EqualFold(item, value) {
			return true
		}
	}
	return false
}