mana_sort       := sort_text@(order: "mixed(Coin|LB|Down|Once|White|Red|Blue|Green|Black|Colorless|ZW|ZR|ZU|ZG|ZB|ZC|W|R|U|G|B|C)")

mana_filter_t := replace@(               # Remove [] used for forcing mana symbols
            match: "[\\[\\]]",
            replace: ""
        ) + { mana_sort() }

mana_context :=
    "(?ix)              # case insensitive, ignore whitespace
     (^|[[:space:]\"(“'])     # start of a word
     (  <match>:            # G: something
     |  <match>,            # G, tap: something
     |  <match>[ ]can[ ]be[ ]pay
     |  (pays?|additional|costs?|the|by # pay X. creatures cost 1 less. pay an additional G.
        |adds?|pay(ed)?[ ](with|using)
        )
        ([ ]either)?             # pay either X or Y
        ([ ](<sym[^>]*>)?(White|Red|Blue|Green|Black|Colorless)+(</sym[^>]*>)?,)* # pay X, Y or Z
        ([ ](<sym[^>]*>)?(White|Red|Blue|Green|Black|Colorless)+(</sym[^>]*>)?[ ](and|or|and/or))* # pay X or Y
        [ ]<match>
        ([,.)]|$                # (end of word)
        |[ ][^ .,]*$            # still typing...
        |[ ]( or | and | in | less | more | to | for ) # or next word is ...
        )
        )
     |  <param-mana><match></param-mana>        # keyword argument that is declared as mana
     |  <param-cost>[ ]*<match></param-cost>    # keyword argument that is declared as cost
     |  <param-cost><match>,            # keyword argument that is declared as cost
     ";

text_filter :=
                                                        # step 1 : remove all automatic tags
    remove_tag@(tag: "<sym-auto>") +
    remove_tag@(tag: "<i-auto>")   +
    remove_tag@(tag: "<b-auto>")   +
    remove_tag@(tag: "<error-spelling") +
    remove_tag@(tag: "<nospellcheck") +
                                                        # step 2 : convert these skills into symbols no matter where they are
    replace@(
        match: "\\[Constant\\]",
        replace: {"<sym-auto>[Constant]</sym-auto>"} ) +
    replace@(
        match: "\\[On-Play\\]",
        replace: {"<sym-auto>[On-Play]</sym-auto>"} ) +
    replace@(
        match: "\\[Action\\]",
        replace: {"<sym-auto>[Action]</sym-auto>"} ) +
    replace@(
        match: "\\[Auto\\]",
        replace: {"<sym-auto>[Auto]</sym-auto>"} ) +
    replace@(
        match: "(>Cross\<)",
        replace: {"<sym-auto>>Cross\<</sym-auto>"} ) +
    replace@(
        match: "with Cross",
        replace: {"with <sym-auto>>Cross\<</sym-auto>"} ) +
    replace@(
        match: "\\[Cross Constant\\]",
        replace: {"<sym-auto>[Cross Constant]</sym-auto>"} ) +
    replace@(
        match: "\\[Cross On-Play\\]",
        replace: {"<sym-auto>[Cross On-Play]</sym-auto>"} ) +
    replace@(
        match: "\\[Cross Action\\]",
        replace: {"<sym-auto>[Cross Action]</sym-auto>"} ) +
    replace@(
        match: "\\[Cross Auto\\]",
        replace: {"<sym-auto>[Cross Auto]</sym-auto>"} ) +
    replace@(
        match: "\\[Attack Phase\\]",
        replace: {"<sym-auto>[Attack Phase]</sym-auto>"} ) +
    replace@(
        match: "\\[Main Phase\\]",
        replace: {"<sym-auto>[Main Phase]</sym-auto>"} ) +
    replace@(
        match: "\\[Spell Cut-In\\]",
        replace: {"<sym-auto>[Spell Cut-In]</sym-auto>"} ) +
    replace@(
        match: "\\(Layer\\)",
        replace: {"<sym-auto>(Layer)</sym-auto>"} ) +
    replace@(
        match: "\\(Play Condition\\)",
        replace: {"<sym-auto>(Play Condition)</sym-auto>"} ) +
    replace@(
        match: "Heaven Heaven",
        replace: {"<sym-auto>Heaven</sym-auto>"} ) +
    replace@(
        match: "Life Burst Life Burst",
        replace: {"LB"} ) +
                                                        # step 3: annoying number replacements
    replace@(
        match: "(1 \<)",
        replace: {"one \<"} ) +
    replace@(
        match: "(2 \<)",
        replace: {"two \<"} ) +
    replace@(
        match: "(3 \<)",
        replace: {"three \<"} ) +
    replace@(
        match: "1 card",
        replace: {"one card"} ) +
    replace@(
        match: "2 cards",
        replace: {"two cards"} ) +
    replace@(
        match: "3 cards",
        replace: {"three cards"} ) +
    replace@(
        match: "1 SIGNI",
        replace: {"one SIGNI"} ) +
    replace@(
        match: "2 SIGNI",
        replace: {"two SIGNI"} ) +
    replace@(
        match: "3 SIGNI",
        replace: {"three SIGNI"} ) +
    replace@(
        match: "1 of",
        replace: {"one of"} ) +
    replace@(
        match: "2 of",
        replace: {"two of"} ) +
    replace@(
        match: "3 of",
        replace: {"three of"} ) +
    # step 5 : add mana & tap symbols
    replace@(
        match: "\\b(Coin|LB|Down|Once|White|Red|Blue|Green|Black|Colorless|ZW|ZR|ZU|ZG|ZB|ZC|W|R|U|G|B|C)+\\b",
        in_context: mana_context,
        replace: {"<sym-auto>" + mana_filter_t() + "</sym-auto>"} ) +
    # step 7 : italicize text in parenthesis
    replace@(
        match: "[(]([^)\n]|[(][^)\n]*[)])*[)]?",
        in_context: "(^|[[:space:]])<match>|<atom-keyword><match></",
        replace: "<i-auto>&</i-auto>") +
    replace@(
        match: "[\<]([^>\n]|[\<][^>\n]*[>])*[>]?",
        in_context: "(^|[[:space:]])<match>|<atom-keyword><match></",
        replace: "<b-auto>&</b-auto>") +
    # step 8 : automatic capitalization, but not after "("
    replace@(
        match: "([ ]*: |—| — )" # preceded by this
             + "([[:lower:]])" # match this
             + "(?![)])",      # not followed by this
        replace: { _1 + to_upper(_2) })