#!/usr/bin/env lua
-- Luash Interactive Shell - A proper REPL
-- Supports multiline input, command history, and all luash features

-- Load the injected library functions
local script_dir = debug.getinfo(1, "S").source:match("@(.*/)")
local lib_file = io.open(script_dir .. "__injected_lib.lua", "r")
if lib_file then
    local lib_code = lib_file:read("*a")
    lib_file:close()
    local lib_func = load(lib_code)
    if lib_func then lib_func() end
end

-- Luash preprocessing functions (copied from main luash script)
local function preprocess_luash(code)
    -- Remove shebang
    code = code:gsub("^#![^\r\n]*[\r\n]?", "")
    
    -- Environment variable processing
    local lines = {}
    for line in code:gmatch("([^\r\n]*)") do
        if not line:match("^%s*%-%-") then -- Skip comments
            -- Handle environment variable assignment: $VAR=value
            if line:match("^%$([%w_]+)%s*=") then
                line = line:gsub("^%$([%w_]+)%s*=%s*(.+)", function(var, value)
                    return "env_set('" .. var .. "', " .. value .. ")"
                end)
            else
                -- Handle $VAR substitution, but not inside strings
                local in_string = false
                local quote_char = nil
                local result = ""
                local i = 1
                
                while i <= #line do
                    local char = line:sub(i, i)
                    
                    if (char == '"' or char == "'") and (i == 1 or line:sub(i-1, i-1) ~= "\\") then
                        if not in_string then
                            in_string = true
                            quote_char = char
                        elseif char == quote_char then
                            in_string = false
                            quote_char = nil
                        end
                        result = result .. char
                        i = i + 1
                    elseif char == "$" and not in_string then
                        local var_match = line:sub(i):match("^%$([%w_]+)")
                        if var_match then
                            result = result .. "env_get('" .. var_match .. "')"
                            i = i + #var_match + 1
                        else
                            result = result .. char
                            i = i + 1
                        end
                    else
                        result = result .. char
                        i = i + 1
                    end
                end
                line = result
            end
        end
        table.insert(lines, line)
    end
    code = table.concat(lines, "\n")
    
    -- Shell command processing
    lines = {}
    for line in code:gmatch("([^\r\n]*)") do
        local in_string = false
        local quote_char = nil
        local result = ""
        local i = 1
        
        while i <= #line do
            local char = line:sub(i, i)
            
            if (char == '"' or char == "'") and (i == 1 or line:sub(i-1, i-1) ~= "\\") then
                if not in_string then
                    in_string = true
                    quote_char = char
                elseif char == quote_char then
                    in_string = false
                    quote_char = nil
                end
                result = result .. char
                i = i + 1
            elseif char == "`" and not in_string then
                local end_pos = line:find("`", i + 1)
                if end_pos then
                    local command = line:sub(i + 1, end_pos - 1)
                    
                    if command:find("#{") then
                        local escaped_cmd = command:gsub('"', '\\"')
                        local interpolated_cmd = escaped_cmd:gsub("#{([%w_.]+)}", '" .. tostring(%1) .. "')
                        result = result .. 'shell("' .. interpolated_cmd .. '")'
                    else
                        result = result .. 'shell("' .. command:gsub('"', '\\"') .. '")'
                    end
                    i = end_pos + 1
                else
                    result = result .. char
                    i = i + 1
                end
            else
                result = result .. char
                i = i + 1
            end
        end
        table.insert(lines, result)
    end
    code = table.concat(lines, "\n")
    
    -- Interactive commands
    lines = {}
    for line in code:gmatch("([^\r\n]*)") do
        local command = line:match("^%s*!(.*)")
        if command then
            local indent = line:match("^(%s*)")
            table.insert(lines, indent .. 'run("' .. command:gsub('"', '\\"') .. '")')
        else
            table.insert(lines, line)
        end
    end
    code = table.concat(lines, "\n")
    
    return code
end

-- Check if expression needs more input (simple heuristic)
local function needs_continuation(code)
    local open_blocks = 0
    local open_parens = 0
    local open_brackets = 0
    local open_braces = 0
    
    local in_string = false
    local quote_char = nil
    
    for i = 1, #code do
        local char = code:sub(i, i)
        
        if not in_string then
            if char == '"' or char == "'" then
                in_string = true
                quote_char = char
            elseif char == "(" then
                open_parens = open_parens + 1
            elseif char == ")" then
                open_parens = open_parens - 1
            elseif char == "[" then
                open_brackets = open_brackets + 1
            elseif char == "]" then
                open_brackets = open_brackets - 1
            elseif char == "{" then
                open_braces = open_braces + 1
            elseif char == "}" then
                open_braces = open_braces - 1
            end
        else
            if char == quote_char and code:sub(i-1, i-1) ~= "\\" then
                in_string = false
                quote_char = nil
            end
        end
    end
    
    -- Check for Lua keywords that need 'end'
    local keywords = {"function", "if", "for", "while", "do", "then"}
    local end_count = 0
    
    for _, keyword in ipairs(keywords) do
        local _, count = code:gsub("%f[%w]" .. keyword .. "%f[%W]", "")
        open_blocks = open_blocks + count
    end
    
    _, end_count = code:gsub("%f[%w]end%f[%W]", "")
    open_blocks = open_blocks - end_count
    
    return open_blocks > 0 or open_parens > 0 or open_brackets > 0 or open_braces > 0 or in_string
end

-- REPL state
local repl = {
    buffer = "",
    history = {},
    history_index = 0
}

-- Add utility functions
function trim(s)
    return s:match("^%s*(.-)%s*$")
end

-- Main REPL function
local function run_repl()
    print("🚀 Luash Interactive Shell")
    print("Type Lua expressions, use $VAR for env vars, `commands` for shell")
    print("Special commands: .help .exit .clear .history")
    print("")
    
    while true do
        local prompt = repl.buffer == "" and "luash> " or "  ... "
        io.write(prompt)
        io.flush()
        
        local line = io.read("*line")
        
        if not line then -- EOF (Ctrl+D)
            print("\nGoodbye!")
            break
        end
        
        line = trim(line)
        
        -- Handle special dot commands
        if line == ".exit" or line == ".quit" then
            break
        elseif line == ".clear" then
            repl.buffer = ""
            print("Buffer cleared")
        elseif line == ".history" then
            for i, cmd in ipairs(repl.history) do
                print(string.format("%3d: %s", i, cmd))
            end
        elseif line == ".help" then
            print([[
Luash Interactive Shell Help:

Luash Features:
  $VAR              - Access environment variables
  $VAR = "value"    - Set environment variables
  `command`         - Execute shell commands
  #{var}            - Variable interpolation in commands
  !command          - Interactive shell commands

Special Commands:
  .help             - Show this help
  .exit, .quit      - Exit the shell
  .clear            - Clear input buffer
  .history          - Show command history

Examples:
  print("Hello " .. $USER)
  files = `ls -la`
  $GREETING = "Hello World"
  result = `echo #{$GREETING}`
  !ps aux | head -5

Multi-line input supported for functions, loops, etc.]])
        else
            -- Add to buffer
            if repl.buffer ~= "" then
                repl.buffer = repl.buffer .. "\n" .. line
            else
                repl.buffer = line
            end
            
            -- Check if we have a complete expression
            if not needs_continuation(repl.buffer) and line ~= "" then
                -- Process and execute
                table.insert(repl.history, repl.buffer)
                
                local processed = preprocess_luash(repl.buffer)
                local func, err = load("return " .. processed, "@repl")
                
                if not func then
                    -- Try without return (for statements)
                    func, err = load(processed, "@repl")
                end
                
                if func then
                    local success, result = pcall(func)
                    if success then
                        if result ~= nil then
                            print(tostring(result))
                        end
                    else
                        print("Error: " .. tostring(result))
                    end
                else
                    print("Syntax error: " .. err)
                end
                
                repl.buffer = ""
            end
        end
    end
end

-- Start the REPL
run_repl()