package sql

import "fmt"

func (p *Parser) parseInsert() (*InsertStatement, error) {
	if !p.expectSequence(INTO, IDENT) {
		return nil, p.unexpectedToken(INTO)
	}

	res := InsertStatement{}

	_, _, res.Table = p.rescan()

	if !p.expectNext(LPAREN) {
		return nil, p.unexpectedToken(LPAREN)
	}

	fieldNames := make([]string, 0)

	for loop := true; loop; {
		_, tok, val := p.scan()
		switch tok {
		case IDENT:
			fieldNames = append(fieldNames, val)
		case RPAREN:
			loop = false
		case COMMA:
			continue
		default:
			return nil, p.unexpectedToken(IDENT, RPAREN, COMMA)
		}
	}

	if !p.expectSequence(VALUES, LPAREN) {
		return nil, p.unexpectedToken()
	}

	values := make([]any, 0, len(fieldNames))
	for loop := true; loop; {
		_, tok, val := p.scan()
		switch tok {
		case IDENT:
			// TODO, convert to actual datatype?
			values = append(values, val)
		case COMMA, QUOTE, SINGLE_QUOTE, BACKQUOTE:
			continue
		case RPAREN:
			loop = false
		default:
			return nil, p.unexpectedToken(IDENT, RPAREN, COMMA)
		}
	}

	if len(values) != len(fieldNames) {
		return nil, fmt.Errorf("Expected same amount of Values as Fields, but got %v fields, and %v values", fieldNames, values)
	}

	// Handle things like RETURNING *, also handle multiple Values
	if !p.consumeUntilOne(50, SEMI, EOF) {
		return nil, fmt.Errorf("Expected semicolon but never found after 50 tries")
	}

	res.Values = make(map[string]any)
	for i, name := range fieldNames {
		res.Values[name] = values[i]
	}

	return &res, nil
}