package tequat

import (
    "bufio"
    "fmt"
    "strings"

    blobs "pkg.jfrech.com/brief/internal/transmigratory/pkg_jfrech_com_go_blobs"
)

// TODO write some tests to make sure atoms are parsed as expected
const dbg = false

func Highlight(mark string) string {
    return "\033[96m" + mark + "\033[m"
}

func (tqa TQA) Format() string {
    esc := func(raw string) string {
        b := new(strings.Builder)
        for _, c := range raw {
            if c > ' ' && c != '"' && c != '\'' && c != '\\' && c <= '~' {
                b.WriteRune(rune(c))
            } else {
                fmt.Fprintf(b, "\\x%02x", int(c))
            }
        }
        return b.String()
    }

    b := new(strings.Builder)
    emitln := func(unterminated string) {
        if strings.ContainsRune(unterminated, '\n') {
            panic("unreachable")
        }
        b.WriteString(unterminated)
        b.WriteRune('\n')
    }
    emit := func(prefix string, raw string) {
        scanner := bufio.NewScanner(strings.NewReader(raw))
        scanner.Buffer(nil, 0xffffff) // [2023-07-19, jfrech] TODO especially minified HTML lines can get *very* long.
        for scanner.Scan() {
            b.WriteString(prefix)
            b.Write(scanner.Bytes())
            b.WriteRune('\n')
        }
        if err := scanner.Err(); err != nil {
            panic("scanner token probably too long: " + err.Error()) // TODO Is this true?
        }
    }

    if dbg {
        emitln(Highlight("{{{"))
    }
    for j, atom := range []Atom(tqa) {
        if dbg && j > 0 {
            emitln(Highlight(";;;"))
        }

        switch a := atom.(type) {
        default:
            emitln(Highlight("???") + " " + esc(fmt.Sprintf("%T", a)))

        case Text:
            emit("", a.Raw)

        case Quote:
            emit(Highlight(">"), a.Raw)

        case DroppedAlternatives:
            b := new(strings.Builder)
            for j, t := range a.MediatypeTs {
                if j != 0 {
                    b.WriteString(", ")
                }
                b.WriteString(esc(t))
            }
            emitln(Highlight("dropped-alternatives:") + " " + b.String())

        case Attachment:
            mark := "attached"
            if a.Inline {
                mark = "attached-inline"
            }
            emitln(Highlight(mark) + " " + esc(a.ContentType()) + " " + esc(blobs.SlurpBytes(a.Data).Short()))

        case SignatureBlock:
            emitln(Highlight("-- "))
            emit("", a.Raw)
        }
    }
    if dbg {
        emitln(Highlight("}}}"))
    }
    return b.String()
}