/*   SHS: Syntactically Homogeneous Shell
 *   Copyright (C) 2019  Aidan Hahn
 *
 *   This program is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation, either version 3 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

package stdlib

import (
    "os"
    "fmt"
    "gitlab.com/whom/shs/log"
    "gitlab.com/whom/shs/ast"
    "gitlab.com/whom/shs/util"
)

/* Makes a FuncTable from all functions in the stdlib
 * add your function here if you are extending the standard library
 */
func GenFuncTable() ast.FuncTable {
    var stdlib ast.FuncTable
    stdlib = &map[string]*ast.Function{
        "if": &ast.Function{
            Function:  ShsIf,
            Name:       "if",
            TimesCalled:   0,
            Args:          3,
        },

        "while": &ast.Function{
            Function:  ShsWhile,
            Name:       "while",
            TimesCalled:      0,
            Args:            -1,
        },

        "progn": &ast.Function{
            Function:   ShsProgn,
            Name:    "shs_progn",
            TimesCalled:       0,
            Args:             -1,
        },

        "func": &ast.Function{
            Function:  DeclFunc,
            Name:   "decl_func",
            TimesCalled:      0,
            Args:             3,
        },

        "len": &ast.Function{
            Function:      Len,
            Name:        "len",
            TimesCalled:     0,
            Args:            1,
        },

        "head": &ast.Function{
            Function:     Head,
            Name:       "head",
            TimesCalled:     0,
            Args:            1,
        },

        "tail": &ast.Function{
            Function:   Tail,
            Name:     "tail",
            TimesCalled:   0,
            Args:          1,
        },

        "slice": &ast.Function{
            Function:   Slice,
            Name:     "slice",
            TimesCalled:    0,
            Args:           3,
        },

        "export": &ast.Function{
            Function: Export,
            Name:   "export",
            TimesCalled:   0,
            Args:          2,
        },

        "input": &ast.Function{
            Function:  Input,
            Name:    "input",
            TimesCalled:   0,
            Args:          1,
        },

        "load": &ast.Function{
            Function:    Load,
            Name:      "load",
            TimesCalled:    0,
            Args:           1,
        },

        "bool": &ast.Function{
            Function:  BoolCast,
            Name:        "bool",
            TimesCalled:      0,
            Args:             1,
        },

        "string": &ast.Function{
            Function:  StrCast,
            Name:     "string",
            TimesCalled:     0,
            Args:            1,
        },

        "number": &ast.Function{
            Function:  NumCast,
            Name:     "number",
            TimesCalled:     0,
            Args:            1,
        },

       "...": &ast.Function{
            Function: Expand,
            Name:      "...",
            TimesCalled:   0,
            Args:          1,
        },

        "append": &ast.Function{
            Function: L_append,
            Name:     "append",
            TimesCalled:     0,
            Args:           -1,
        },

        "join": &ast.Function{
            Function:    Join,
            Name:      "join",
            TimesCalled:    0,
            Args:           2,
        },

        "split": &ast.Function{
            Function:   Split,
            Name:     "split",
            TimesCalled:    0,
            Args:           2,
        },

        "exit": &ast.Function{
            Function:  ExitShell,
            Name:         "exit",
            TimesCalled:       0,
            Args:              0,
        },

        "eq": &ast.Function{
            Function:         Eq,
            Name:           "==",
            TimesCalled:       0,
            Args:              2,
        },

        "ne": &ast.Function{
            Function:         Ne,
            Name:           "!=",
            TimesCalled:       0,
            Args:              2,
        },

        "<": &ast.Function{
            Function:         Lt,
            Name:            "<",
            TimesCalled:       0,
            Args:              2,
        },

        ">": &ast.Function{
            Function:         Gt,
            Name:            ">",
            TimesCalled:       0,
            Args:              2,
        },

        "<=": &ast.Function{
            Function:        Lte,
            Name:           "<=",
            TimesCalled:       0,
            Args:              2,
        },

        ">=": &ast.Function{
            Function:        Gte,
            Name:           ">=",
            TimesCalled:       0,
            Args:              2,
        },

        "!": &ast.Function{
            Function:        Not,
            Name:            "!",
            TimesCalled:       0,
            Args:              1,
        },

        "+": &ast.Function{
            Function:      Add,
            Name:        "add",
            TimesCalled:     0,
            Args:           -1,
        },

        "-": &ast.Function{
            Function:      Sub,
            Name:        "sub",
            TimesCalled:     0,
            Args:           -1,
        },

        "*": &ast.Function{
            Function:     Mult,
            Name:       "mult",
            TimesCalled:     0,
            Args:           -1,
        },

        "/": &ast.Function{
            Function:      Div,
            Name:        "div",
            TimesCalled:     0,
            Args:           -1,
        },

        "cd": &ast.Function{
            Function:       Cd,
            Name:  "changedir",
            TimesCalled:     0,
            Args:            1,
        },

        "concat": &ast.Function{
            Function:   Concat,
            Name:"concatenate",
            TimesCalled:     0,
            Args:           -1,
        },

        "print": &ast.Function{
            Function: PrintStr,
            Name:      "print",
            TimesCalled:     0,
            Args:            1,
        },

        "l": &ast.Function{
            Function:     Call,
            Name:       "call",
            TimesCalled:     0,
            Args:           -1,
        },

        "bg": &ast.Function{
            Function:        Bgcall,
            Name: "background call",
            TimesCalled:          0,
            Args:                -1,
        },

        "fg": &ast.Function{
            Function:       Fg,
            Name: "foreground",
            TimesCalled:     0,
            Args:            1,
        },

        "$": &ast.Function{
            Function:  ReadCmd,
            Name:   "read cmd",
            TimesCalled:     0,
            Args:           -1,
        },

        "?": &ast.Function{
            Function:    GetExit,
            Name:"get exit code",
            TimesCalled:       0,
            Args:              0,
        },

        /*
        USE NATIVE KILL COMMAND.
        "kill": &ast.Function{
            Function:       kill,
            Name:     "kill job",
            TimesCalled:       0,
            Args:              1,
        },
        */

        "jobs": &ast.Function{
            Function:       Jobs,
            Name:    "list jobs",
            TimesCalled:       0,
            Args:              0,
        },

        "info": &ast.Function{
            Function:     ShInfo,
            Name:   "Shell Info",
            TimesCalled:       0,
            Args:              1,
        },

        "fexists": &ast.Function{
            Function:    Fexists,
            Name:  "file exists",
            TimesCalled:       0,
            Args:              1,
        },

        "fread": &ast.Function{
            Function:      Fread,
            Name:    "read file",
            TimesCalled:       0,
            Args:              1,
        },

        "fwrite": &ast.Function{
            Function:     Fwrite,
            Name:   "write file",
            TimesCalled:       0,
            Args:              2,
        },

        "fappend": &ast.Function{
            Function:     Fappend,
            Name:"append to file",
            TimesCalled:        0,
            Args:               2,
        },
    }

    return stdlib
}

/* takes no args
 * exits shell when called
 *
 * Example: (exit)
 */
func ExitShell(in *ast.Token, vt ast.VarTable, ft ast.FuncTable) *ast.Token {
    os.Exit(0)
    return nil // I hope execution doesnt get here
}

/* takes one arg, doesnt evaluate it
 * returns type or metadata
 * 
 * Example: (info append)
 */
func ShInfo(in *ast.Token, vt ast.VarTable, ft ast.FuncTable) *ast.Token {
    switch in.Tag {
    case ast.BOOL:
        fmt.Printf("BOOL LITERAL\nValue: %s\n", in.Value())
    case ast.STRING:
        fmt.Printf("STRING LITERAL \nValue: %s\n", in.Value())
    case ast.NUMBER:
        fmt.Printf("NUMBER LITERAL \nValue: %s\n", in.Value())
    case ast.LIST:
        fmt.Printf("LIST \nString Value: %s, AST:\n", in.String())
        ast.PrintSExprsIndividually(in)
    case ast.SYMBOL:
        repr := ast.GetVar(in.Value(), vt)
        if repr != nil {
            fmt.Printf("VARIABLE\nTYPE: %s\nVALUE: %s\n", ast.GetTagAsStr(repr.Tag), repr.Value())
            break
        }

        funct := ast.GetFunction(in.Value(), ft)
        if funct != nil {
            fmt.Printf("FUNCTION\nNAME: %s\nTIMES CALLED: %s\nNUM ARGS: %d\n", funct.Name, funct.TimesCalled, funct.Args)
            break
        }

        fmt.Printf("UNKNOWN SYMBOL\n")
    }

    return nil
}

/* Takes 1 arg, uses it as a prompt
 * errs if prompt is not a string or number
 * gets a line from stdin
 * returns it as a string
 *
 * Example: (print (input))
 */
func Input(in *ast.Token, vt ast.VarTable, ft ast.FuncTable) *ast.Token {
    in = in.Eval(ft, vt, false)
    if in.Tag != ast.STRING && in.Tag != ast.NUMBER {
        log.Log(log.ERR,
            "argument to input must be a string or number",
            "input")
        return nil
    }

    prompt := in.Value()
    var output string

    fmt.Printf(prompt)
    fmt.Scanln(&output)

    ret := &ast.Token{Tag: ast.STRING}
    ret.Set(output)
    return ret
}

/* Takes 1 arg, returns nil
 * if arg is a valid existing file than load will execute it as a script
 *
 * Example: (load "myscript.shs")
 */
func Load(in *ast.Token, vt ast.VarTable, ft ast.FuncTable) *ast.Token {
    in = in.Eval(ft, vt, true)
    if in.Tag != ast.STRING {
        log.Log(log.ERR,
            "argument to load must be a string",
            "load")
        return nil
    }

    bp := in.Value()
    bp = AbsPath(bp)
    util.LoadScript(bp, vt, ft)
    return nil
}