package textfmt

import (
	"bytes"
	"errors"
	"fmt"
	"io"
	"strings"
)

func ttyTextToString(text Txt) string {
	var b bytes.Buffer
	renderTTYText(&b, text)
	return b.String()
}

func ttyDefinitionNames(d []DefinitionItem) []string {
	var n []string
	for _, di := range d {
		n = append(n, ttyTextToString(di.name))
	}

	return n
}

func renderTTYText(w io.Writer, text Txt) {
	if len(text.cat) > 0 {
		for i, tc := range text.cat {
			if i > 0 {
				write(w, " ")
			}

			renderTTYText(w, tc)
		}

		return
	}

	var f func() (io.Writer, error)
	w, f = writeWith(w, escapeTeletype(), singleLine())
	if text.link == "" {
		write(w, text.text)
		f()
		return
	}

	if text.text == "" {
		write(w, text.link)
		f()
		return
	}

	write(w, text.text)
	write(w, " (")
	write(w, text.link)
	write(w, ")")
	f()
}

func renderTTYTitle(w io.Writer, e Entry) {
	write(w, timesn(" ", e.indent))
	renderTTYText(w, e.text)
}

func renderTTYParagraph(w io.Writer, e Entry) {
	var indentation wrapper
	indentFirst := e.indent + e.indentFirst
	wrapWidthFirst := e.wrapWidth + e.wrapWidthFirst
	if e.wrapWidth == 0 {
		indentation = indent(indentFirst, e.indent)
	} else {
		indentation = wrapIndent(indentFirst, e.indent, wrapWidthFirst, e.wrapWidth)
	}

	w, f := writeWith(w, indentation)
	renderTTYText(w, e.text)
	f()
}

func renderTTYList(w io.Writer, e Entry) {
	for i, item := range e.items {
		if i > 0 {
			write(w, "\n")
		}

		p := itemToParagraph(e, item.text, "-")
		renderTTYParagraph(w, p)
	}
}

func renderTTYNumberedList(w io.Writer, e Entry) {
	maxDigits := numDigits(len(e.items))
	for i, item := range e.items {
		if i > 0 {
			write(w, "\n")
		}

		p := itemToParagraph(e, item.text, padRight(fmt.Sprintf("%d.", i+1), maxDigits+1))
		renderTTYParagraph(w, p)
	}
}

func renderTTYDefinitions(w io.Writer, e Entry) {
	names := ttyDefinitionNames(e.definitions)
	maxNameLength := maxLength(names)
	for i, definition := range e.definitions {
		if i > 0 {
			write(w, "\n")
		}

		p := itemToParagraph(
			e,
			definition.value,
			padRight(fmt.Sprintf("- %s:", names[i]), maxNameLength+3),
		)

		renderTTYParagraph(w, p)
	}
}

func renderTTYNumberedDefinitions(w io.Writer, e Entry) {
	names := ttyDefinitionNames(e.definitions)
	maxNameLength := maxLength(names)
	maxDigits := numDigits(len(e.definitions))
	for i, definition := range e.definitions {
		if i > 0 {
			write(w, "\n")
		}

		p := itemToParagraph(
			e,
			definition.value,
			padRight(
				fmt.Sprintf(
					"%s %s:",
					padRight(fmt.Sprintf("%d.", i+1), maxDigits+1),
					names[i],
				),
				maxNameLength+maxDigits+3,
			),
		)

		renderTTYParagraph(w, p)
	}
}

func ttyCellTexts(rows []TableRow) [][]string {
	var cellTexts [][]string
	for _, row := range rows {
		var c []string
		for _, cell := range row.cells {
			txt := ttyTextToString(cell.text)
			c = append(c, txt)
		}

		cellTexts = append(cellTexts, c)
	}

	return cellTexts
}

func renderTTYTable(w io.Writer, e Entry) {
	if len(e.rows) == 0 {
		return
	}

	e.rows = normalizeTable(e.rows)
	if len(e.rows[0].cells) == 0 {
		return
	}

	cellTexts := ttyCellTexts(e.rows)
	totalSeparatorWidth := (len(cellTexts[0]) - 1) * 3
	if e.wrapWidth > 0 {
		allocatedWidth := e.wrapWidth - e.indent - totalSeparatorWidth
		columnWeights := columnWeights(cellTexts)
		targetColumnWidths := targetColumnWidths(allocatedWidth, columnWeights)
		for i := range cellTexts {
			for j := range cellTexts[i] {
				width := targetColumnWidths[j]
				cellTexts[i][j] = editString(cellTexts[i][j], wrap(width, width))
			}
		}
	}

	columnWidths := columnWidths(cellTexts)
	totalWidth := totalSeparatorWidth
	for i := range columnWidths {
		totalWidth += columnWidths[i]
	}

	hasHeader := e.rows[0].header
	w, f := writeWith(w, indent(e.indent, e.indent))
	for i := range cellTexts {
		if i > 0 {
			sep := "-"
			if hasHeader && i == 1 {
				sep = "="
			}

			write(w, "\n")
			write(w, timesn(sep, totalWidth))
			write(w, "\n")
		}

		lines := make([][]string, len(cellTexts[i]))
		for j := range cellTexts[i] {
			lines[j] = strings.Split(cellTexts[i][j], "\n")
		}

		var maxLines int
		for j := range lines {
			if len(lines[j]) > maxLines {
				maxLines = len(lines[j])
			}
		}

		for k := 0; k < maxLines; k++ {
			if k > 0 {
				write(w, "\n")
			}

			for j := range lines {
				if j > 0 {
					write(w, " | ")
				}

				var l string
				if k < len(lines[j]) {
					l = lines[j][k]
				}

				write(w, padRight(l, columnWidths[j]))
			}
		}
	}

	if hasHeader && len(cellTexts) == 1 {
		write(w, "\n", timesn("=", totalWidth))
	}

	f()
}

func renderTTYCode(w io.Writer, e Entry) {
	w, f := writeWith(w, escapeTeletype(), indent(e.indent, e.indent))
	write(w, e.text.text)
	f()
}

func renderTTYMultiple(w io.Writer, s SyntaxItem) {
	s.topLevel = false
	s.multiple = false
	renderTTYSyntaxItem(w, s)
	write(w, "...")
}

func renderTTYRequired(w io.Writer, s SyntaxItem) {
	s.delimited = true
	s.topLevel = false
	s.required = false
	write(w, "<")
	renderTTYSyntaxItem(w, s)
	write(w, ">")
}

func renderTTYOptional(w io.Writer, s SyntaxItem) {
	s.delimited = true
	s.topLevel = false
	s.optional = false
	write(w, "[")
	renderTTYSyntaxItem(w, s)
	write(w, "]")
}

func renderTTYSequence(w io.Writer, s SyntaxItem) {
	if !s.delimited && !s.topLevel {
		write(w, "(")
	}

	for i, item := range s.sequence {
		if i > 0 {
			write(w, " ")
		}

		item.delimited = false
		renderTTYSyntaxItem(w, item)
	}

	if !s.delimited && !s.topLevel {
		write(w, ")")
	}
}

func renderTTYChoice(w io.Writer, s SyntaxItem) {
	if !s.delimited && !s.topLevel {
		write(w, "(")
	}

	for i, item := range s.choice {
		if i > 0 {
			separator := "|"
			if s.topLevel {
				separator = "\n"
			}

			write(w, separator)
		}

		item.delimited = false
		renderTTYSyntaxItem(w, item)
	}

	if !s.delimited && !s.topLevel {
		write(w, ")")
	}
}

func renderTTYSymbol(w io.Writer, s SyntaxItem) {
	write(w, s.symbol)
}

func renderTTYSyntaxItem(w io.Writer, s SyntaxItem) {
	switch {

	// foo...
	case s.multiple:
		renderTTYMultiple(w, s)

	// <foo>
	case s.required:
		renderTTYRequired(w, s)

	// [foo]
	case s.optional:
		renderTTYOptional(w, s)

	// foo bar baz or (foo bar baz)
	case len(s.sequence) > 0:
		renderTTYSequence(w, s)

	// foo|bar|baz or (foo|bar|baz)
	case len(s.choice) > 0:
		renderTTYChoice(w, s)

	// foo
	default:
		renderTTYSymbol(w, s)
	}
}

func renderTTYSyntax(w io.Writer, e Entry) {
	w, f := writeWith(w, escapeTeletype(), indent(e.indent, e.indent))
	s := e.syntax
	s.topLevel = true
	renderTTYSyntaxItem(w, s)
	f()
}

func renderTeletype(out io.Writer, d Document) error {
	w, f := writeWith(out, ttyNBSP(), errorHandler)
	for i, e := range d.entries {
		if i > 0 {
			write(w, "\n\n")
		}

		switch e.typ {
		case title:
			renderTTYTitle(w, e)
		case paragraph:
			renderTTYParagraph(w, e)
		case list:
			renderTTYList(w, e)
		case numberedList:
			renderTTYNumberedList(w, e)
		case definitions:
			renderTTYDefinitions(w, e)
		case numberedDefinitions:
			renderTTYNumberedDefinitions(w, e)
		case table:
			renderTTYTable(w, e)
		case code:
			renderTTYCode(w, e)
		case syntax:
			renderTTYSyntax(w, e)
		default:
			return errors.New("invalid entry")
		}
	}

	if len(d.entries) > 0 {
		write(w, "\n")
	}

	_, err := f()
	return err
}