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// Copyright (c) 2019-2024 Alexander Medvednikov. All rights reserved.
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// Use of this source code is governed by an MIT license
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// that can be found in the LICENSE file.
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module csv
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import strings
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struct Writer {
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	use_crlf  bool
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	delimiter u8
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mut:
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	sb strings.Builder
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}
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@[params]
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pub struct WriterConfig {
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pub:
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	use_crlf  bool
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	delimiter u8 = `,`
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}
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// new_writer returns a reference to a Writer
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pub fn new_writer(config WriterConfig) &Writer {
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	return &Writer{
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		sb:        strings.new_builder(200)
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		use_crlf:  config.use_crlf
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		delimiter: config.delimiter
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	}
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}
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// write writes a single record
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pub fn (mut w Writer) write(record []string) !bool {
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	if !valid_delim(w.delimiter) {
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		return &InvalidDelimiterError{}
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	}
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	le := if w.use_crlf { '\r\n' } else { '\n' }
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	for n, field_ in record {
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		mut field := field_
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		if n > 0 {
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			w.sb.write_string(w.delimiter.ascii_str())
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		}
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		if !w.field_needs_quotes(field) {
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			w.sb.write_string(field)
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			continue
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		}
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		w.sb.write_string('"')
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		for field.len > 0 {
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			mut i := field.index_any('"\r\n')
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			if i < 0 {
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				i = field.len
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			}
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			w.sb.write_string(field[..i])
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			field = field[i..]
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			if field.len > 0 {
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				z := field[0]
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				match z {
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					`"` { w.sb.write_string('""') }
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					`\r`, `\n` { w.sb.write_string(le) }
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					else {}
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				}
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				field = field[1..]
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			}
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		}
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		w.sb.write_string('"')
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	}
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	w.sb.write_string(le)
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	return true
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}
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// Once we have multi dimensional array
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// pub fn (w &Writer) write_all(records [][]string) {
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// 	for _, record in records {
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// 		w.write(record)
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// 	}
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// }
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fn (w &Writer) field_needs_quotes(field string) bool {
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	if field == '' {
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		return false
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	}
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	if field.contains(w.delimiter.ascii_str()) || field.index_any('"\r\n') != -1 {
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		return true
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	}
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	return false
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}
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// str returns the writer contents
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pub fn (mut w Writer) str() string {
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	return w.sb.str()
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}
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