// Copyright 2025 Dolthub, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package node

import (
	"context"

	"github.com/cockroachdb/errors"
	"github.com/dolthub/go-mysql-server/sql"
	"github.com/dolthub/go-mysql-server/sql/plan"
	vitess "github.com/dolthub/vitess/go/vt/sqlparser"

	"github.com/dolthub/doltgresql/core"
	"github.com/dolthub/doltgresql/core/extensions"
	"github.com/dolthub/doltgresql/core/id"
	"github.com/dolthub/doltgresql/core/procedures"
	"github.com/dolthub/doltgresql/server/plpgsql"
)

// CreateProcedure implements CREATE PROCEDURE.
type CreateProcedure struct {
	ProcedureName     string
	SchemaName        string
	Replace           bool
	Parameters        []RoutineParam
	Statements        []plpgsql.InterpreterOperation
	ExtensionName     string
	ExtensionSymbol   string
	Definition        string
	SqlDef            string
	SqlDefParsedStmts []vitess.Statement
}

var _ sql.ExecSourceRel = (*CreateProcedure)(nil)
var _ vitess.Injectable = (*CreateProcedure)(nil)

// NewCreateProcedure returns a new *CreateProcedure.
func NewCreateProcedure(
	procedureName string,
	schemaName string,
	replace bool,
	params []RoutineParam,
	definition string,
	extensionName string,
	extensionSymbol string,
	statements []plpgsql.InterpreterOperation,
	sqlDef string,
	sqlDefParsedStmts []vitess.Statement) *CreateProcedure {
	return &CreateProcedure{
		ProcedureName:     procedureName,
		SchemaName:        schemaName,
		Replace:           replace,
		Parameters:        params,
		Statements:        statements,
		ExtensionName:     extensionName,
		ExtensionSymbol:   extensionSymbol,
		Definition:        definition,
		SqlDef:            sqlDef,
		SqlDefParsedStmts: sqlDefParsedStmts,
	}
}

// Children implements the interface sql.ExecSourceRel.
func (c *CreateProcedure) Children() []sql.Node {
	return nil
}

// IsReadOnly implements the interface sql.ExecSourceRel.
func (c *CreateProcedure) IsReadOnly() bool {
	return false
}

// Resolved implements the interface sql.ExecSourceRel.
func (c *CreateProcedure) Resolved() bool {
	return true
}

// RowIter implements the interface sql.ExecSourceRel.
func (c *CreateProcedure) RowIter(ctx *sql.Context, _ sql.Row) (sql.RowIter, error) {
	procCollection, err := core.GetProceduresCollectionFromContext(ctx, "")
	if err != nil {
		return nil, err
	}

	paramTypes := make([]id.Type, len(c.Parameters))
	paramNames := make([]string, len(c.Parameters))
	paramModes := make([]procedures.ParameterMode, len(c.Parameters))
	paramDefaults := make([]string, len(c.Parameters))
	for i, param := range c.Parameters {
		paramNames[i] = param.Name
		paramTypes[i] = param.Type.ID
		if param.Default != nil {
			paramDefaults[i] = param.Default.String()
		}
	}

	schemaName, err := core.GetSchemaName(ctx, nil, c.SchemaName)
	if err != nil {
		return nil, err
	}
	procID := id.NewProcedure(schemaName, c.ProcedureName, paramTypes...)
	if c.Replace && procCollection.HasProcedure(ctx, procID) {
		if err = procCollection.DropProcedure(ctx, procID); err != nil {
			return nil, err
		}
	}
	var extName string
	if len(c.ExtensionName) > 0 {
		ext, err := extensions.GetExtension(c.ExtensionName)
		if err != nil {
			return nil, err
		}
		ident := extensions.CreateLibraryIdentifier(c.ExtensionName, ext.Control.DefaultVersion)
		_, err = extensions.GetExtensionFunction(extensions.CreateLibraryIdentifier(c.ExtensionName, ext.Control.DefaultVersion), c.ExtensionSymbol)
		if err != nil {
			return nil, err
		}
		extName = string(ident)
	}
	err = procCollection.AddProcedure(ctx, procedures.Procedure{
		ID:                procID,
		ParameterNames:    paramNames,
		ParameterTypes:    paramTypes,
		ParameterModes:    paramModes,
		ParameterDefaults: paramDefaults,
		Definition:        c.Definition,
		ExtensionName:     extName,
		ExtensionSymbol:   c.ExtensionSymbol,
		Operations:        c.Statements,
		SQLDefinition:     c.SqlDef,
	})
	if err != nil {
		return nil, err
	}
	return sql.RowsToRowIter(), nil
}

// Schema implements the interface sql.ExecSourceRel.
func (c *CreateProcedure) Schema(ctx *sql.Context) sql.Schema {
	return nil
}

// String implements the interface sql.ExecSourceRel.
func (c *CreateProcedure) String() string {
	return "CREATE PROCEDURE"
}

// WithChildren implements the interface sql.ExecSourceRel.
func (c *CreateProcedure) WithChildren(ctx *sql.Context, children ...sql.Node) (sql.Node, error) {
	return plan.NillaryWithChildren(c, children...)
}

// WithResolvedChildren implements the interface vitess.Injectable.
func (c *CreateProcedure) WithResolvedChildren(ctx context.Context, children []any) (any, error) {
	if len(children) > len(c.Parameters) {
		// the number of default values can be fewer but cannot be more.
		return nil, ErrVitessChildCount.New(len(c.Parameters), len(children))
	}
	newParams := make([]RoutineParam, len(c.Parameters))
	childIdx := 0
	for i, param := range c.Parameters {
		newParams[i] = param
		if c.Parameters[i].HasDefault && childIdx < len(children) {
			expr, ok := children[childIdx].(sql.Expression)
			if !ok {
				return nil, errors.Errorf("invalid vitess child, expected sql.Expression for Default value but got %t", children[i])
			}
			newParams[i].Default = expr
			childIdx++
		}
	}
	ncp := *c
	ncp.Parameters = newParams
	return &ncp, nil
}