package main

import (
	"go/ast"
	"go/parser"
	"go/token"
	"os"
	"path/filepath"
	"regexp"
	"strings"
)

type rawSQLViolation struct {
	file    string
	line    int
	snippet string
}

// SQL keywords that indicate raw SQL usage
var sqlKeywordRe = regexp.MustCompile(`(?i)\b(INSERT\s+INTO|UPDATE\s+\w+\s+SET|DELETE\s+FROM|SELECT\s+.+\s+FROM|ALTER\s+TABLE|DROP\s+TABLE|CREATE\s+TABLE)\b`)

// Directories where raw SQL is expected (migrations, sqlc queries, seeder, test fixtures)
func isRawSQLAllowed(path string) bool {
	return strings.Contains(path, "/sql/") ||
		strings.Contains(path, "/migrations/") ||
		strings.Contains(path, "/internal/db/") ||
		strings.Contains(path, "/seeder/") ||
		strings.HasSuffix(path, "_test.go") ||
		strings.Contains(path, "/cmd/admincli/") ||
		strings.Contains(path, "/datasources/") || // Bob query builder files
		strings.Contains(path, "internal/plugins/") // Plugin tables are not in core schema
}

// Specific SQL patterns that are allowed (postgres admin commands, not data queries)
var allowedSQLPatterns = []string{
	"pg_terminate_backend", // backup_service.go — kills connections before restore
	"FROM pg_database",     // Administrative catalog lookup for tenant database existence
	"FROM pg_roles",        // role_provisioner.go — per-plugin role existence lookup (DCL, not sqlc-able)
}

func isSQLAllowed(sql string) bool {
	for _, pattern := range allowedSQLPatterns {
		if strings.Contains(sql, pattern) {
			return true
		}
	}
	return false
}

// checkRawSQL finds raw SQL string literals passed to Exec/Query methods outside allowed dirs.
func checkRawSQL(root string) []rawSQLViolation {
	var violations []rawSQLViolation

	if err := filepath.Walk(root, func(path string, info os.FileInfo, err error) error {
		if err != nil || info.IsDir() || !strings.HasSuffix(path, ".go") {
			return nil
		}
		if strings.Contains(path, "/vendor/") {
			return nil
		}
		if isRawSQLAllowed(path) {
			return nil
		}

		fset := token.NewFileSet()
		f, err := parser.ParseFile(fset, path, nil, 0)
		if err != nil {
			return nil
		}

		relPath, _ := filepath.Rel(root, path)

		ast.Inspect(f, func(n ast.Node) bool {
			call, ok := n.(*ast.CallExpr)
			if !ok {
				return true
			}

			// Match method calls: *.ExecContext, *.QueryContext, *.QueryRowContext, *.Exec, *.Query, *.QueryRow
			sel, ok := call.Fun.(*ast.SelectorExpr)
			if !ok {
				return true
			}
			method := sel.Sel.Name
			isDBMethod := method == "ExecContext" || method == "QueryContext" || method == "QueryRowContext" ||
				method == "Exec" || method == "Query" || method == "QueryRow"
			if !isDBMethod {
				return true
			}

			// Check if any string argument contains SQL keywords
			for _, arg := range call.Args {
				lit, ok := arg.(*ast.BasicLit)
				if !ok || lit.Kind != token.STRING {
					continue
				}
				val := strings.Trim(lit.Value, "`\"")
				if sqlKeywordRe.MatchString(val) && !isSQLAllowed(val) {
					pos := fset.Position(call.Pos())
					// Truncate the SQL for display
					display := val
					if len(display) > 80 {
						display = display[:77] + "..."
					}
					violations = append(violations, rawSQLViolation{
						file:    relPath,
						line:    pos.Line,
						snippet: display,
					})
				}
			}
			return true
		})

		return nil
	}); err != nil {
		violations = append(violations, rawSQLViolation{file: root, line: 0, snippet: err.Error()})
	}

	return violations
}