Fibble/src/FibLib/Library.fs

namespace Fibble.FibLib

open System.Net
open FParsec
open YamlDotNet.Serialization
open System.Collections.Generic


// ==========================================
// 1. AST & Utils
// ==========================================
module Ast =
    type InlineNode =
        | Text of string
        | RawHtml of string
        | Expr of code: string * result: string option
        | Element of tag: string * args: (string * string) list * children: InlineNode list

    type BlockNode =
        | Section of level: int * args: (string * string) list * children: InlineNode list
        | Paragraph of children: InlineNode list

    type Document = BlockNode list

    type TagRenderer = Map<string,string> -> (string * string) list -> InlineNode list -> InlineNode

    let rec stringifyNodes (nodes: InlineNode list) =
        let tupleToString (t: string * string) = sprintf "%s=\"%s\"" (fst t) (snd t) 
        nodes 
        |> List.map (function
            | Text t -> t
            | RawHtml h -> h
            | Element(tag, args, children) -> 
                // Omvandla inre taggar till HTML
                let attrs = if args.IsEmpty then "" else " " + String.concat " " (List.map tupleToString args) 
                sprintf "<%s%s>%s</%s>" tag attrs (stringifyNodes children) tag
            | Expr(_, Some res) -> res
            | Expr(code, None) -> sprintf "@(%s)" code // Fallback om den inte evaluerats
        ) 
        |> String.concat ""



module Utils =
    open Ast
    let smartDedent (input: string) =
        let lines = input.Replace("\r\n", "\n").Split '\n' |> List.ofArray
        
        // 1. Hitta den minsta indenteringen bland alla rader som har text
        let minIndent = 
            lines 
            |> List.filter (fun l -> not (System.String.IsNullOrWhiteSpace(l)))
            |> List.map (fun l -> l.Length - l.TrimStart().Length)
            |> function
                | [] -> 0
                | indents -> List.min indents

        // 2. Dra av exakt så många mellanslag från alla rader
        // för att dessa inte ska vara med i det slutgiltiga dokumentet.
        let dedented =
            lines
            |> List.map (fun l ->
                if System.String.IsNullOrWhiteSpace(l) then ""
                else l.Substring(minIndent)
            )
        
        // 3. Slå ihop och städa bort överflödiga radbrytningar i början/slutet
        (String.concat "\n" dedented).Trim('\n', '\r')

    let positional f: TagRenderer =
        fun meta (args: (string*string) list) children -> f meta (List.map snd args) children

    let getArgIdx (args: (string*string) list)  index defaultVal =
        let unnamed = args |> List.filter (fun (k, _) -> k = "")
        if index < unnamed.Length then (snd unnamed.[index]).Trim('"')
        else defaultVal

    // This gets the arg defined by "key" unless it is not set, it then tries to get it by index. If that fails, it gets the defaultVal
    let getArg (args: (string * string) list) (key: string) (index: int) (defaultVal: string) =
        match args |> List.tryFind (fun (k, _) -> k = key) with
        | Some (_, v) -> v.Trim('"')
        | None -> getArgIdx args index defaultVal
            
    let withArg1 def (f: string -> InlineNode list -> InlineNode) =
        fun _ args children -> f (getArgIdx args 0 def) children

    let withArg2 (k1: string) (d1: string) (k2: string) (d2: string) (f: string -> string -> InlineNode list -> InlineNode) =
        fun _ args children -> f (getArg args k1 0 d1) (getArg args k2 1 d2) children

    let nameToElement (n:string) : TagRenderer =
        fun meta args children -> Element(n, args, children)
        




// ==========================================
// 2. Parser
// ==========================================

module Parser =
    open Ast

    let pInline, pInlineRef = createParserForwardedToRef<InlineNode, unit>()

    let getSectionLevel (name: string) =
        if name = "section" then 1
        elif name = "subsection" then 2
        elif name.StartsWith("sub") && name.EndsWith("section") then (name.Length - 7) / 3 + 1
        else 1

    let isSection (name: string) = name.EndsWith("section")

    let pNewline = newline
    let pArg = 
        spaces >>. 
        choice [
            attempt (many1Chars (asciiLetter <|> digit <|> anyOf "-_") 
                     .>> spaces .>> pchar '=' .>> spaces 
                     .>>. manyChars (noneOf ",]"))
            |>> fun (k, v) -> (k, v.Trim())
            
            // Fallback: bara "värde" (ges en tom nyckel)
            manyChars (noneOf ",]") |>> fun v -> ("", v.Trim())
        ] .>> spaces
    let pArgs = between (pstring "[") (pstring "]") (sepBy pArg (pstring ","))

    // --- 1. Måsvinge-parser (för @kommandon) ---
    let pRawBody, pRawBodyRef = createParserForwardedToRef<string, unit>()
    pRawBodyRef.Value <- 
        many (choice [ 
            many1Chars (noneOf "{}")
            pchar '{' >>. pRawBodyRef.Value .>> pchar '}' |>> sprintf "{%s}" 
        ]) |>> String.concat ""

    let pBody = 
        between (pstring "{") (pstring "}") pRawBodyRef.Value >>= fun raw ->
            // En mer tillåtande parser isolerad för innehållet inuti {...}
            let pInnerInline =
                choice [
                    attempt pInline
                    // Fångar upp dubbla radbrytningar och måsvingar som pInline normalt blockerar
                    many1Chars (anyOf "\r\n{}") |>> Text 
                ]
                
            match run (many pInnerInline .>> eof) (Utils.smartDedent raw) with
            | Success(n, _, _) -> preturn n
            | Failure(m, _, _) -> fail m

    // --- 2. Parentes-parser (för @(...) med sträng-stöd) ---
    let pParenBody, pParenBodyRef = createParserForwardedToRef<string, unit>()

    // En inre parser som känner igen F#-strängar och escape-tecken (\")
    let pFSharpString =
        let normal = many1Chars (noneOf "\"\\")
        let escaped = pstring "\\" >>. anyChar |>> sprintf "\\%c"
        pstring "\"" .>>. manyStrings (normal <|> escaped) .>>. pstring "\""
        |>> fun ((start, inner), end_) -> start + inner + end_

    // Själva loopen letar nu efter strängar FÖRST, sen vanlig text, och sist inre parenteser
    pParenBodyRef.Value <- 
        manyStrings (choice [ 
            pFSharpString
            many1Chars (noneOf "()\"")
            pchar '(' >>. pParenBody .>> pchar ')' |>> sprintf "(%s)" 
        ])

    let pExpr = 
        attempt (pstring "@(") >>. pParenBody .>> pstring ")" 
        |>> fun c -> Expr(c, None)

    // --- Övriga inline-parsers ---
    let pMultilineCode = 
        pstring "@\"\"\"" >>. manyCharsTill anyChar (pstring "\"\"\"") 
        |>> fun c -> Expr(Utils.smartDedent c, None)
        
    let pInlineCommand = 
        attempt (
            pchar '@' >>. many1Chars asciiLetter >>= fun name ->
                if isSection name then fail "Sektioner är block-element."
                else preturn name
        ) 
        .>>. opt pArgs 
        .>>. opt pBody 
        |>> fun ((n, a), b) -> Element(n, defaultArg a [], defaultArg b [])

    // MÅSTE tilldelas efter att alla pExpr, pInlineCommand etc. är definierade
    pInlineRef.Value <- choice [ 
        pMultilineCode
        pExpr
        pInlineCommand
        many1Chars (noneOf "@{}\n\r") |>> Text
        attempt (pNewline .>> notFollowedBy pNewline) |>> fun _ -> Text "\n" 
        pchar '@' |>> fun _ -> Text "@" 
    ]

    // --- Block Parsers ---
    let pSectionBlock =
        attempt (
            pchar '@' >>. many1Chars asciiLetter >>= fun name ->
                if isSection name then preturn name
                else fail "Inte en sektion."
        ) 
        .>>. opt pArgs 
        .>>. opt pBody
        |>> fun ((name, argsOpt), bodyOpt) ->
            Section(getSectionLevel name, defaultArg argsOpt [], defaultArg bodyOpt [])

    let pParagraphBlock = many1 pInline |>> Paragraph

    let pBlock = choice [ pSectionBlock; pParagraphBlock ]

    // --- Dokument Parser ---
    let pDocument = 
        spaces 
        >>. opt (
            pstring "---" 
            >>. manyCharsTill anyChar (attempt (pNewline >>. pstring "---")) 
            |>> fun yamlStr -> 
                let deserializer = DeserializerBuilder().Build()
                let dict = deserializer.Deserialize<Dictionary<string, string>>(yamlStr)
                if isNull dict then Map.empty
                else dict |> Seq.map (fun kvp -> kvp.Key, kvp.Value) |> Map.ofSeq
        ) 
        .>> spaces 
        .>>. sepEndBy pBlock (many1 pNewline)
        .>> eof
        |>> fun (headerOpt, blocks) ->
            (defaultArg headerOpt Map.empty, blocks)

    let parse i = 
        match run pDocument i with 
        | Success(r, _, _) -> r 
        | Failure(e, _, _) -> failwith e


// ==========================================
// 3. Execution & Printer
// ==========================================
type IEvaluator =
    abstract member Evaluate: string -> string

module Execution =
    open Ast

    let rec transform (metadata: Map<string, string>) (prelude: Map<string, TagRenderer>) (eval: IEvaluator) = function
        | Element(n, a, c) when prelude.ContainsKey n -> 
            prelude.[n] metadata a (c |> List.map (transform metadata prelude eval))
        | Element(n, a, c) -> 
            Element(n, a, c |> List.map (transform metadata prelude eval))
        | Expr(c, _) -> RawHtml (eval.Evaluate c)
        | n -> n

module HtmlPrinter =
    open Ast
    let voidElements = [ "area"; "base"; "br"; "col"; "command"; "embed"; "hr"; "img"; "input"; "keygen"; "link"; "meta"; "param"; "source"; "track"; "wbr"]
    let renderAttributes args =
        args
        |> List.map (fun m -> sprintf "%s=\"%s\"" (fst m) (snd m))
        |> String.concat " "
    let rec renderInline =
        function
        | Text t -> WebUtility.HtmlEncode t
        | RawHtml h -> h
        | Element(t,a,c) when List.contains t voidElements -> sprintf "<%s %s />" t (renderAttributes a)
        | Element(t, a, c) -> sprintf "<%s %s>%s</%s>" t (renderAttributes a) (c |> List.map renderInline |> String.concat "") t
        | _ -> ""

    let render (header, blocks) =
        blocks
        |> List.map (function
            | Paragraph [RawHtml html] -> 
                     html
        
    // 2. (Frivillig) Mer robust guard om parsern råkar lämna kvar 
    // blanksteg (Text " ") runt ditt @md-block i samma paragraf
            | Paragraph nodes when nodes |> List.forall (function 
                                                         | RawHtml _ -> true 
                                                         | Text t when System.String.IsNullOrWhiteSpace(t) -> true 
                                                         | _ -> false) ->
        
                nodes 
                |> List.choose (function RawHtml h -> Some h | _ -> None) 
                |> String.concat "\n"
            | Paragraph c -> sprintf "<p>%s</p>" (c |> List.map renderInline |> String.concat "")
            | Section(l, _, c) -> sprintf "<h%d>%s</h%d>" l (c |> List.map renderInline |> String.concat "") l)
        |> String.concat "\n"


module Evaluators =
    open System.IO
    open System.Text
    open FSharp.Compiler.Interactive.Shell

    type FsiEvaluator() =
        let sbOut = new StringBuilder()
        let sbErr = new StringBuilder()
        let inStream = new StringReader("")
        let outStream = new StringWriter(sbOut)
        let errStream = new StringWriter(sbErr)

        // Initiera FSI-sessionen
        let fsiConfig = FsiEvaluationSession.GetDefaultConfiguration()
        let argv = [| "fsi.exe"; "--noninteractive" |]
        let session = FsiEvaluationSession.Create(fsiConfig, argv, inStream, outStream, errStream)

        interface IEvaluator with
            member _.Evaluate(code: string) =
                sbOut.Clear() |> ignore
                sbErr.Clear() |> ignore

                try
                    let result, _warnings = session.EvalInteractionNonThrowing(code)

                    let output = sbOut.ToString()
                    let errors = sbErr.ToString().Trim()

                    // Filtrera bort FSI:s automatiska typsignaturer från utskriften
                    let cleanOutput =
                        output.Replace("\r\n", "\n").Split('\n')
                        |> Array.filter (fun line -> 
                            let l = line.TrimStart()
                            not (l.StartsWith("val ") || l.StartsWith("type ") || l.StartsWith("module ") || l.StartsWith("namespace "))
                        )
                        |> String.concat "\n"
                        |> fun s -> s.Trim()

                    match result with
                    | Choice1Of2 (Some fsiValue) ->
                        // Plocka ut värdet. Om det är en sträng, undvik "%A" för att slippa citattecken.
                        let valStr = 
                            if isNull fsiValue.ReflectionValue then ""
                            else
                                match fsiValue.ReflectionValue with
                                | :? string as s -> s
                                | v -> sprintf "%A" v
                                
                        if System.String.IsNullOrEmpty(cleanOutput) then valStr
                        elif System.String.IsNullOrEmpty(valStr) then cleanOutput
                        else cleanOutput + "\n" + valStr
                        
                    | Choice1Of2 None ->
                        if not (System.String.IsNullOrEmpty(errors)) then
                            cleanOutput + sprintf "%A" errors
                        else
                            cleanOutput 
                        
                    | Choice2Of2 ex ->
                        let fsiErrorOutput = if System.String.IsNullOrEmpty(errors) then "Ingen ytterligare FSI-output." else errors
                        sprintf """
                        <div style="color: #721c24; background-color: #f8d7da; border-color: #f5c6cb; padding: 10px; margin-bottom: 10px; border-radius: 5px;">
                            <strong>FSI Exekveringsfel!</strong><br/>
                            <strong>Kod som kördes:</strong> <code>%s</code><br/><br/>
                            <strong>Exception:</strong> %s<br/>
                            <strong>FSI Stderr:</strong> <pre style="margin:0; background: rgba(255,255,255,0.5); padding: 5px;">%s</pre>
                        </div>""" code ex.Message fsiErrorOutput
                        
                with ex ->
                    sprintf """<div style="color: red; border: 1px solid red; padding: 10px;">
                                <strong>Kritiskt FSI-systemfel:</strong> %s
                               </div>""" ex.Message