# Builtins & external libs
import sequtils
import strformat
import strutils
import nimSHA2
import times
import jale/editor as ed
import jale/templates
import jale/plugin/defaults
import jale/plugin/editor_history
import jale/keycodes
import jale/multiline


# Our stuff
import frontend/lexer as l
import frontend/parser as p
import frontend/compiler as c
import backend/vm as v
# TODO: Broken
# import frontend/optimizer as o
import util/serializer as s
import util/debugger


# Forward declarations
proc fillSymbolTable(tokenizer: Lexer)
proc getLineEditor: LineEditor

# Handy dandy compile-time constants
const debugLexer = false
const debugParser = false
const debugCompiler = true
const debugOptimizer = false
const debugSerializer = true


when isMainModule:
    setControlCHook(proc () {.noconv.} = quit(0))
    var
        keep = true
        tokens: seq[Token] = @[]
        tree: seq[ASTNode] = @[]
        compiled: Chunk
        # optimized: tuple[tree: seq[ASTNode], warnings: seq[Warning]]
        serialized: Serialized
        serializedRaw: seq[byte]
        tokenizer = newLexer()
        parser = newParser()
        # optimizer = newOptimizer()
        compiler = newCompiler()
        serializer = newSerializer()
        vm = newPeonVM()
        editor = getLineEditor()
        input: string
    tokenizer.fillSymbolTable()
    editor.bindEvent(jeQuit):
        keep = false
    editor.bindKey("ctrl+a"):
        editor.content.home()
    editor.bindKey("ctrl+e"):
        editor.content.`end`()
    while keep:
        try:
            input = editor.read()
            if input.len() == 0:
                continue
            # Currently the parser doesn't handle these tokens well
            tokens = filter(tokenizer.lex(input, "<stdin>"), proc (x: Token): bool = x.kind notin {TokenType.Whitespace, Tab})
            if tokens.len() == 0:
                continue
            when debugLexer:
                echo "Tokenization step:"
                for i, token in tokens:
                    if i == tokens.high():
                        # Who cares about EOF?
                        break
                    echo "\t", token
                echo ""
            tree = parser.parse(tokens, "<stdin>")
            when debugParser:
                echo "Parsing step:"
                for node in tree:
                    echo "\t", node
                echo ""
            # The optimizer needs work to function properly
            # with the compiler
            # optimized = optimizer.optimize(tree)
            when debugOptimizer:
                echo &"Optimization step (constant folding enabled: {optimizer.foldConstants}):"
                for node in optimized.tree:
                    echo "\t", node
                echo ""
                stdout.write(&"Produced warnings: ")
                if optimized.warnings.len() > 0:
                    echo ""
                    for warning in optimized.warnings:
                        echo "\t", warning
                else:
                    stdout.write("No warnings produced\n")
                echo ""
            compiled = compiler.compile(tree, "<stdin>")
            when debugCompiler:
                echo "Compilation step:"
                stdout.write("\t")
                echo &"""Raw byte stream: [{compiled.code.join(", ")}]"""
                echo "\nBytecode disassembler output below:\n"
                disassembleChunk(compiled, "<stdin>")
                echo ""
            when debugSerializer:
                echo "Serialization step: "

                echo "Dumping bytecode to 'stdin.pbc'\n"
                serializer.dumpToFile(compiled, input, "<stdin>", "stdin.pbc")
                serializedRaw = serializer.dumpBytes(compiled, input, "<stdin>")

                echo "Loading 'stdin.pbc'\n"
                serialized = serializer.loadFile("stdin.pbc")
                echo "Deserialized 'stdin.pbc':"
                stdout.write("\t")
                echo &"""Raw hex output: {serializedRaw.mapIt(toHex(it)).join("").toLowerAscii()}"""
                echo ""

                echo &"\t- File hash: {serialized.fileHash} (matches: {computeSHA256(input).toHex().toLowerAscii() == serialized.fileHash})"
                echo &"\t- Peon version: {serialized.peonVer.major}.{serialized.peonVer.minor}.{serialized.peonVer.patch} (commit {serialized.commitHash[0..8]} on branch {serialized.peonBranch})"
                stdout.write("\t")
                echo &"""- Compilation date & time: {fromUnix(serialized.compileDate).format("d/M/yyyy HH:mm:ss")}"""
                stdout.write(&"\t- Reconstructed constants table: [")
                for i, e in serialized.chunk.consts:
                    stdout.write(e)
                    if i < len(serialized.chunk.consts) - 1:
                        stdout.write(", ")
                stdout.write("]\n")
                stdout.write(&"\t- Reconstructed bytecode: [")
                for i, e in serialized.chunk.code:
                    stdout.write($e)
                    if i < len(serialized.chunk.code) - 1:
                        stdout.write(", ")
                stdout.write(&"] (matches: {serialized.chunk.code == compiled.code})\n")
            echo "Execution step: "
            vm.run(serialized.chunk)
        except IOError:
            break
    # TODO: The code for error reporting completely
    # breaks down with multiline input, fix it
        except LexingError:
            let lineNo = tokenizer.getLine()
            let relPos = tokenizer.getRelPos(lineNo)
            let line = tokenizer.getSource().splitLines()[lineNo - 1].strip()
            echo getCurrentExceptionMsg()
            echo &"Source line: {line}"
            echo " ".repeat(relPos.start + len("Source line: ")) & "^".repeat(relPos.stop - relPos.start)
        except ParseError:
            let lineNo = parser.getCurrentToken().line
            let relPos = tokenizer.getRelPos(lineNo)
            let line = tokenizer.getSource().splitLines()[lineNo - 1].strip()
            echo getCurrentExceptionMsg()
            echo &"Source line: {line}"
            echo " ".repeat(relPos.start + len("Source line: ")) & "^".repeat(relPos.stop - parser.getCurrentToken().lexeme.len())
        except CompileError:
            let lineNo = compiler.getCurrentNode().token.line
            let relPos = tokenizer.getRelPos(lineNo)
            let line = tokenizer.getSource().splitLines()[lineNo - 1].strip()
            echo getCurrentExceptionMsg()
            echo &"Source line: {line}"
            echo " ".repeat(relPos.start + len("Source line: ")) & "^".repeat(relPos.stop - compiler.getCurrentNode().token.lexeme.len())
        except SerializationError:
            echo getCurrentExceptionMsg()
    quit(0)



proc fillSymbolTable(tokenizer: Lexer) =
    ## Initializes the Lexer's symbol
    ## table with the builtin symbols
    ## and keywords
    
    # 1-byte symbols
    tokenizer.symbols.addSymbol("+", Plus)
    tokenizer.symbols.addSymbol("-", Minus)
    tokenizer.symbols.addSymbol("*", Star)
    tokenizer.symbols.addSymbol("/", Slash)
    tokenizer.symbols.addSymbol("{", LeftBrace)
    tokenizer.symbols.addSymbol("}", RightBrace)
    tokenizer.symbols.addSymbol("(", LeftParen)
    tokenizer.symbols.addSymbol(")", RightParen)
    tokenizer.symbols.addSymbol("[", LeftBracket)
    tokenizer.symbols.addSymbol("]", RightBracket)
    tokenizer.symbols.addSymbol(".", Dot)
    tokenizer.symbols.addSymbol(",", Comma)
    tokenizer.symbols.addSymbol(">", TokenType.GreaterThan)
    tokenizer.symbols.addSymbol("<", TokenType.LessThan)
    tokenizer.symbols.addSymbol(";", Semicolon)
    tokenizer.symbols.addSymbol("=", Equal)
    tokenizer.symbols.addSymbol("~", Tilde)
    tokenizer.symbols.addSymbol("%", Percentage)
    tokenizer.symbols.addSymbol(":", Colon)
    tokenizer.symbols.addSymbol("&", Ampersand)
    tokenizer.symbols.addSymbol("^", Caret)
    tokenizer.symbols.addSymbol("|", Pipe)
    # 2-byte symbols
    tokenizer.symbols.addSymbol("+=", InplaceAdd)
    tokenizer.symbols.addSymbol("-=", InplaceSub)
    tokenizer.symbols.addSymbol(">=", TokenType.GreaterOrEqual)
    tokenizer.symbols.addSymbol("<=", TokenType.LessOrEqual)
    tokenizer.symbols.addSymbol("*=", InplaceMul)
    tokenizer.symbols.addSymbol("/=", InplaceDiv)
    tokenizer.symbols.addSymbol("&=", InplaceAnd)
    tokenizer.symbols.addSymbol("!=", NotEqual)
    tokenizer.symbols.addSymbol("|=", InplaceOr)
    tokenizer.symbols.addSymbol("^=", InplaceXor)
    tokenizer.symbols.addSymbol("%=", InplaceMod)
    tokenizer.symbols.addSymbol("//", FloorDiv)
    tokenizer.symbols.addSymbol("==", DoubleEqual)
    tokenizer.symbols.addSymbol("**", DoubleStar)
    tokenizer.symbols.addSymbol(">>", RightShift)
    tokenizer.symbols.addSymbol("<<", LeftShift)
    # 3-byte symbols
    tokenizer.symbols.addSymbol("//=", InplaceFloorDiv)
    tokenizer.symbols.addSymbol("**=", InplacePow)
    tokenizer.symbols.addSymbol(">>=", InplaceRightShift)
    tokenizer.symbols.addSymbol("<<=", InplaceLeftShift)
    # Keywords
    tokenizer.symbols.addKeyword("type", Type)
    tokenizer.symbols.addKeyword("enum", Enum)
    tokenizer.symbols.addKeyword("case", Case)
    tokenizer.symbols.addKeyword("operator", Operator)
    tokenizer.symbols.addKeyword("generator", Generator)
    tokenizer.symbols.addKeyword("function", Function)
    tokenizer.symbols.addKeyword("coroutine", Coroutine)
    tokenizer.symbols.addKeyword("break", TokenType.Break)
    tokenizer.symbols.addKeyword("continue", Continue)
    tokenizer.symbols.addKeyword("while", While)
    tokenizer.symbols.addKeyword("for", For)
    tokenizer.symbols.addKeyword("foreach", Foreach)
    tokenizer.symbols.addKeyword("if", If)
    tokenizer.symbols.addKeyword("else", Else)
    tokenizer.symbols.addKeyword("await", TokenType.Await)
    tokenizer.symbols.addKeyword("defer", Defer)
    tokenizer.symbols.addKeyword("try", Try)
    tokenizer.symbols.addKeyword("except", Except)
    tokenizer.symbols.addKeyword("finally", Finally)
    tokenizer.symbols.addKeyword("raise", TokenType.Raise)
    tokenizer.symbols.addKeyword("assert", TokenType.Assert)
    tokenizer.symbols.addKeyword("const", Const)
    tokenizer.symbols.addKeyword("let", Let)
    tokenizer.symbols.addKeyword("var", Var)
    tokenizer.symbols.addKeyword("import", Import)
    tokenizer.symbols.addKeyword("yield", TokenType.Yield)
    tokenizer.symbols.addKeyword("return", TokenType.Return)
    # These are more like expressions with a reserved 
    # name that produce a value of a builtin type, 
    # but we don't need to care about that until 
    # we're in the parsing/ compilation steps so 
    # it's fine
    tokenizer.symbols.addKeyword("nan", NotANumber)
    tokenizer.symbols.addKeyword("inf", Infinity)
    tokenizer.symbols.addKeyword("nil", TokenType.Nil)
    tokenizer.symbols.addKeyword("true", TokenType.True)
    tokenizer.symbols.addKeyword("false", TokenType.False)
    # These are technically operators, but since
    # they fit neatly into the definition for an
    # identifier/keyword we parse them as such
    # and specialize them later
    tokenizer.symbols.addKeyword("isnot", IsNot)
    tokenizer.symbols.addKeyword("is", Is)
    tokenizer.symbols.addKeyword("as", As)
    tokenizer.symbols.addKeyword("of", Of)
    tokenizer.symbols.addKeyword("and", TokenType.LogicalAnd)
    tokenizer.symbols.addKeyword("or", TokenType.LogicalOr)
    tokenizer.symbols.addKeyword("not", TokenType.LogicalNot)

    # P.S.: There's no reason for the order of addition of
    # symbols to be ascending in length (the symbol table uses 
    # a hashmap internally). You can add/remove symbols (and
    # keywords for that matter) as you like!


proc getLineEditor: LineEditor =
    result = newLineEditor()
    result.prompt = "=> "
    result.populateDefaults()
    let history = result.plugHistory()
    result.bindHistory(history)