#!/usr/bin/env bash
set -euo pipefail

# =============================================================================
# setup-go-module.sh — Inicializa módulo Go funcional con bindings Python
# Coherente con DevFactory (pure core / impure shell) + CGO c-shared + ctypes
# =============================================================================

# --- Colores ---
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[0;34m'
CYAN='\033[0;36m'
NC='\033[0m'

log_info()  { echo -e "${BLUE}[INFO]${NC} $1"; }
log_ok()    { echo -e "${GREEN}[OK]${NC} $1"; }
log_warn()  { echo -e "${YELLOW}[WARN]${NC} $1"; }
log_error() { echo -e "${RED}[ERROR]${NC} $1"; }
log_step()  { echo -e "${CYAN}[STEP]${NC} $1"; }

# --- Parámetros ---
MODULE_NAME="${1:-}"
TARGET_PATH="${2:-.}"
DEVFACTORY_PATH="$HOME/.local_agentes/backend"
DEVFACTORY_MODULE="github.com/lucasdataproyects/devfactory"

# --- Validar nombre ---
if [[ -z "$MODULE_NAME" ]]; then
    log_error "Uso: setup-go-module.sh <nombre> [path]"
    echo "STATUS: ERROR"
    exit 1
fi

# Normalizar nombre a kebab-case
MODULE_NAME=$(echo "$MODULE_NAME" | tr '[:upper:]' '[:lower:]' | sed 's/[^a-z0-9-]/-/g' | sed 's/--*/-/g' | sed 's/^-\|-$//g')
PROJECT_DIR="$TARGET_PATH/$MODULE_NAME"

# --- Check estado existente ---
if [[ -f "$PROJECT_DIR/go.mod" ]]; then
    log_warn "El módulo $MODULE_NAME ya existe en $PROJECT_DIR"
    if [[ -f "$PROJECT_DIR/export/exports.go" ]]; then
        log_ok "Bindings Python ya configurados"
    else
        log_warn "Falta directorio export/ — ejecuta de nuevo para completar"
    fi
    echo "STATUS: CONFIGURED"
    exit 0
fi

# --- Verificar dependencias ---
log_step "Verificando dependencias..."

if ! command -v go &>/dev/null; then
    log_error "Go no está instalado. Instala Go 1.22+"
    echo "STATUS: ERROR"
    exit 1
fi

GO_VERSION=$(go version | grep -oP '\d+\.\d+' | head -1)
log_ok "Go $GO_VERSION encontrado"

if ! command -v python3 &>/dev/null; then
    log_warn "Python3 no encontrado — los bindings se generarán pero no se podrán testear"
fi

if [[ ! -d "$DEVFACTORY_PATH" ]]; then
    log_warn "DevFactory no encontrado en $DEVFACTORY_PATH — se creará go.mod sin go.work"
fi

# --- Crear estructura ---
log_step "Creando estructura del módulo '$MODULE_NAME'..."

mkdir -p "$PROJECT_DIR"/{core,shell,export,python/bindings,cmd,internal}

# --- go.mod ---
log_step "Generando go.mod..."
cat > "$PROJECT_DIR/go.mod" << EOF
module github.com/lucasdataproyects/$MODULE_NAME

go 1.22

require $DEVFACTORY_MODULE v0.0.0
EOF

# --- go.work (si DevFactory existe localmente) ---
if [[ -d "$DEVFACTORY_PATH" ]]; then
    log_step "Generando go.work con DevFactory local..."
    cat > "$PROJECT_DIR/go.work" << EOF
go 1.22

use (
    .
    $DEVFACTORY_PATH
)
EOF
    log_ok "go.work enlazado a DevFactory"
fi

# --- core/transform.go — Funciones puras de ejemplo ---
log_step "Generando core/ (funciones puras)..."
cat > "$PROJECT_DIR/core/transform.go" << 'GOEOF'
// Package core contiene funciones puras sin side effects.
// Todas las funciones son deterministas y composables.
package core

import (
	"strings"

	"errors"

	df "github.com/lucasdataproyects/devfactory/core"
)

// ToUpper transforma texto a mayúsculas (función pura).
func ToUpper(s string) string {
	return strings.ToUpper(s)
}

// ProcessItems aplica una transformación a cada elemento usando MapSlice de DevFactory.
func ProcessItems(items []string, transform func(string) string) []string {
	return df.MapSlice(items, transform)
}

// FilterNonEmpty filtra elementos vacíos usando FilterSlice de DevFactory.
func FilterNonEmpty(items []string) []string {
	return df.FilterSlice(items, func(s string) bool {
		return len(strings.TrimSpace(s)) > 0
	})
}

// SafeDivide retorna Result[float64] para evitar panic en división por cero.
func SafeDivide(a, b float64) df.Result[float64] {
	if b == 0 {
		return df.Err[float64](errors.New("division by zero"))
	}
	return df.Ok(a / b)
}
GOEOF

# --- core/types.go — Tipos exportables a Python ---
cat > "$PROJECT_DIR/core/types.go" << 'GOEOF'
package core

// DataPoint representa un punto de datos exportable a Python.
// Los campos usan tipos C-compatible para facilitar el binding.
type DataPoint struct {
	Label string
	Value float64
}

// Summary es el resultado de un procesamiento, exportable a Python.
type Summary struct {
	Count int
	Total float64
	Items []string
}
GOEOF

# --- shell/io.go — Operaciones I/O con Result[T] ---
log_step "Generando shell/ (operaciones I/O)..."
cat > "$PROJECT_DIR/shell/io.go" << 'GOEOF'
// Package shell contiene operaciones con side effects, wrapeadas en Result[T].
package shell

import (
	df "github.com/lucasdataproyects/devfactory/core"
	"github.com/lucasdataproyects/devfactory/shell"
)

// ReadDataFile lee un archivo y retorna su contenido como Result.
func ReadDataFile(path string) df.Result[string] {
	return shell.ReadString(path)
}

// WriteResult escribe un resultado a archivo.
func WriteResult(path string, content string) df.Result[struct{}] {
	return shell.WriteString(path, content)
}
GOEOF

# --- export/exports.go — Funciones exportadas via CGO ---
log_step "Generando export/ (bindings CGO)..."
cat > "$PROJECT_DIR/export/exports.go" << GOEOF
// Package main exporta funciones Go como C shared library.
// Cada función con //export se expone como símbolo C callable desde Python.
package main

import "C"
import (
	"encoding/json"
	"unsafe"

	"github.com/lucasdataproyects/$MODULE_NAME/core"
)

//export GoToUpper
func GoToUpper(input *C.char) *C.char {
	result := core.ToUpper(C.GoString(input))
	return C.CString(result)
}

//export GoProcessItems
func GoProcessItems(jsonInput *C.char) *C.char {
	var items []string
	if err := json.Unmarshal([]byte(C.GoString(jsonInput)), &items); err != nil {
		return C.CString("[]")
	}
	result := core.ProcessItems(items, core.ToUpper)
	out, _ := json.Marshal(result)
	return C.CString(string(out))
}

//export GoFilterNonEmpty
func GoFilterNonEmpty(jsonInput *C.char) *C.char {
	var items []string
	if err := json.Unmarshal([]byte(C.GoString(jsonInput)), &items); err != nil {
		return C.CString("[]")
	}
	result := core.FilterNonEmpty(items)
	out, _ := json.Marshal(result)
	return C.CString(string(out))
}

//export GoSafeDivide
func GoSafeDivide(a, b C.double) *C.char {
	result := core.SafeDivide(float64(a), float64(b))
	if result.IsErr() {
		return C.CString(`{"error":"` + result.Error().Error() + `"}`)
	}
	out, _ := json.Marshal(map[string]float64{"value": result.Unwrap()})
	return C.CString(string(out))
}

//export GoFree
func GoFree(ptr *C.char) {
	C.free(unsafe.Pointer(ptr))
}

func main() {}
GOEOF

# --- python/bindings/__init__.py — Wrapper ctypes auto-generado ---
log_step "Generando python/bindings/ (ctypes wrapper)..."

# Nombre de la shared library según OS
SO_NAME="lib${MODULE_NAME}.so"

cat > "$PROJECT_DIR/python/bindings/__init__.py" << PYEOF
"""
Auto-generated Python bindings for $MODULE_NAME.
Uses ctypes to call Go functions compiled as C shared library.

Usage:
    from bindings import to_upper, process_items, filter_non_empty, safe_divide
"""
import ctypes
import json
import os
from pathlib import Path

# Localizar la shared library
_LIB_DIR = Path(__file__).parent.parent.parent / "build"
_LIB_NAME = "$SO_NAME"
_LIB_PATH = _LIB_DIR / _LIB_NAME

if not _LIB_PATH.exists():
    raise FileNotFoundError(
        f"Shared library not found at {_LIB_PATH}. "
        f"Run 'make build' in the project root first."
    )

_lib = ctypes.CDLL(str(_LIB_PATH))

# --- Configurar tipos de retorno ---
_lib.GoToUpper.argtypes = [ctypes.c_char_p]
_lib.GoToUpper.restype = ctypes.c_char_p

_lib.GoProcessItems.argtypes = [ctypes.c_char_p]
_lib.GoProcessItems.restype = ctypes.c_char_p

_lib.GoFilterNonEmpty.argtypes = [ctypes.c_char_p]
_lib.GoFilterNonEmpty.restype = ctypes.c_char_p

_lib.GoSafeDivide.argtypes = [ctypes.c_double, ctypes.c_double]
_lib.GoSafeDivide.restype = ctypes.c_char_p

_lib.GoFree.argtypes = [ctypes.c_char_p]
_lib.GoFree.restype = None


def to_upper(text: str) -> str:
    """Convert text to uppercase using Go core."""
    result = _lib.GoToUpper(text.encode("utf-8"))
    return result.decode("utf-8")


def process_items(items: list[str]) -> list[str]:
    """Process items through Go pipeline (ToUpper transformation)."""
    input_json = json.dumps(items).encode("utf-8")
    result = _lib.GoProcessItems(input_json)
    return json.loads(result.decode("utf-8"))


def filter_non_empty(items: list[str]) -> list[str]:
    """Filter empty strings using Go core."""
    input_json = json.dumps(items).encode("utf-8")
    result = _lib.GoFilterNonEmpty(input_json)
    return json.loads(result.decode("utf-8"))


def safe_divide(a: float, b: float) -> float:
    """Safe division using Go Result type. Raises ValueError on division by zero."""
    result = _lib.GoSafeDivide(ctypes.c_double(a), ctypes.c_double(b))
    data = json.loads(result.decode("utf-8"))
    if "error" in data:
        raise ValueError(data["error"])
    return data["value"]
PYEOF

# --- python/example.py ---
cat > "$PROJECT_DIR/python/example.py" << PYEOF
"""Example usage of $MODULE_NAME Go bindings from Python."""
from bindings import to_upper, process_items, filter_non_empty, safe_divide

# String transformation
print(to_upper("hello from go"))  # HELLO FROM GO

# Batch processing via Go's MapSlice
items = ["hello", "world", "from", "go"]
print(process_items(items))  # ["HELLO", "WORLD", "FROM", "GO"]

# Filtering via Go's FilterSlice
mixed = ["hello", "", "world", "  ", "go"]
print(filter_non_empty(mixed))  # ["hello", "world", "go"]

# Safe division with Result[T] error handling
print(safe_divide(10.0, 3.0))  # 3.333...
try:
    safe_divide(10.0, 0.0)
except ValueError as e:
    print(f"Caught: {e}")  # Caught: division by zero
PYEOF

# --- core/transform_test.go ---
log_step "Generando tests..."
cat > "$PROJECT_DIR/core/transform_test.go" << 'GOEOF'
package core

import (
	"testing"
)

func TestToUpper(t *testing.T) {
	if got := ToUpper("hello"); got != "HELLO" {
		t.Errorf("ToUpper(\"hello\") = %q, want %q", got, "HELLO")
	}
}

func TestFilterNonEmpty(t *testing.T) {
	items := []string{"hello", "", "world", "  ", "go"}
	result := FilterNonEmpty(items)
	if len(result) != 3 {
		t.Errorf("FilterNonEmpty got %d items, want 3", len(result))
	}
}

func TestSafeDivide(t *testing.T) {
	ok := SafeDivide(10, 2)
	if ok.IsErr() {
		t.Error("SafeDivide(10, 2) should not error")
	}
	if ok.Unwrap() != 5.0 {
		t.Errorf("SafeDivide(10, 2) = %f, want 5.0", ok.Unwrap())
	}

	err := SafeDivide(10, 0)
	if !err.IsErr() {
		t.Error("SafeDivide(10, 0) should error")
	}
}
GOEOF

# --- Makefile ---
log_step "Generando Makefile..."
cat > "$PROJECT_DIR/Makefile" << MKEOF
.PHONY: build test clean python dev

MODULE_NAME := $MODULE_NAME
BUILD_DIR := build
SO_NAME := $SO_NAME

## build: Compila la shared library (.so) para Python
build:
	@mkdir -p \$(BUILD_DIR)
	cd export && CGO_ENABLED=1 go build -buildmode=c-shared -o ../\$(BUILD_DIR)/\$(SO_NAME) .
	@echo "✓ Built \$(BUILD_DIR)/\$(SO_NAME)"

## test: Ejecuta tests de Go
test:
	go test ./core/... ./shell/... -v

## python: Compila y ejecuta ejemplo Python
python: build
	cd python && python3 example.py

## clean: Limpia artefactos
clean:
	rm -rf \$(BUILD_DIR)
	find . -name "__pycache__" -type d -exec rm -rf {} + 2>/dev/null || true

## dev: Tests + build en un paso
dev: test build
	@echo "✓ Ready — run 'make python' to test bindings"

## tidy: go mod tidy
tidy:
	go mod tidy

## help: Muestra esta ayuda
help:
	@grep -E '^## ' Makefile | sed 's/## //' | column -t -s ':'
MKEOF

# --- .gitignore ---
cat > "$PROJECT_DIR/.gitignore" << 'EOF'
build/
*.so
*.h
*.dylib
*.dll
__pycache__/
*.pyc
.pytest_cache/
EOF

# --- go mod tidy ---
log_step "Ejecutando go mod tidy..."
cd "$PROJECT_DIR"
if [[ -f "go.work" ]]; then
    go mod tidy 2>/dev/null || log_warn "go mod tidy falló — revisa el go.work"
else
    go mod tidy 2>/dev/null || log_warn "go mod tidy falló — DevFactory no está disponible"
fi

# --- Resumen ---
echo ""
log_ok "Módulo '$MODULE_NAME' creado en $PROJECT_DIR"
echo ""
echo -e "${CYAN}Estructura:${NC}"
echo "  $MODULE_NAME/"
echo "  ├── core/           — Funciones puras (sin side effects)"
echo "  ├── shell/          — Operaciones I/O con Result[T]"
echo "  ├── export/         — Funciones exportadas via CGO"
echo "  ├── python/bindings — Wrapper ctypes auto-generado"
echo "  ├── Makefile        — build, test, python, clean"
echo "  └── go.work         — Enlace a DevFactory"
echo ""
echo -e "${CYAN}Comandos:${NC}"
echo "  make test    — Ejecutar tests Go"
echo "  make build   — Compilar shared library"
echo "  make python  — Testear bindings Python"
echo "  make dev     — Test + build en un paso"
echo ""
echo "STATUS: READY"