package cli

import (
	"fmt"
	"io"
	"os"
	"path/filepath"
	"strings"

	"beelloo/internal/invoice"
	"beelloo/internal/render"
	"beelloo/internal/server"
)

func Run(args []string, out io.Writer, errOut io.Writer) int {
	if len(args) == 0 {
		usage(errOut)
		return 2
	}
	switch args[0] {
	case "new":
		return runNew(args[1:], out, errOut)
	case "emit":
		return runBuild(args[1:], out, errOut)
	case "build":
		return runBuild(args[1:], out, errOut)
	case "serve":
		return runServe(args[1:], out, errOut)
	case "-h", "--help", "help":
		usage(out)
		return 0
	default:
		fmt.Fprintf(errOut, "unknown command: %s\n", args[0])
		usage(errOut)
		return 2
	}
}

func usage(w io.Writer) {
	fmt.Fprintln(w, "Usage:")
	fmt.Fprintln(w, "  beelloo new <file.md>")
	fmt.Fprintln(w, "  beelloo build <file.md> [--css=style.css]")
	fmt.Fprintln(w, "  beelloo serve <file.md> [--addr=127.0.0.1:0] [--css=style.css]")
}

func runNew(args []string, out io.Writer, errOut io.Writer) int {
	if len(args) != 1 {
		fmt.Fprintln(errOut, "new requires a single file path")
		return 2
	}
	path := args[0]
	if err := os.WriteFile(path, []byte(invoice.ScaffoldMarkdown), 0644); err != nil {
		fmt.Fprintf(errOut, "failed to write scaffold: %v\n", err)
		return 1
	}
	fmt.Fprintf(out, "scaffold written to %s\n", path)
	return 0
}

func runBuild(args []string, out io.Writer, errOut io.Writer) int {
	if len(args) < 1 {
		fmt.Fprintln(errOut, "build requires a markdown file path")
		return 2
	}
	path := args[0]
	cssPath := ""
	for _, arg := range args[1:] {
		if strings.HasPrefix(arg, "--css=") {
			cssPath = strings.TrimPrefix(arg, "--css=")
		}
	}

	file, err := os.Open(path)
	if err != nil {
		fmt.Fprintf(errOut, "failed to open %s: %v\n", path, err)
		return 1
	}
	defer file.Close()

	doc, err := invoice.ParseMarkdown(file)
	if err != nil {
		fmt.Fprintf(errOut, "parse error: %v\n", err)
		return 1
	}
	if err := invoice.Validate(&doc); err != nil {
		fmt.Fprintf(errOut, "validation error: %v\n", err)
		return 1
	}

	html, err := renderWithCSS(doc, cssPath)
	if err != nil {
		fmt.Fprintf(errOut, "render error: %v\n", err)
		return 1
	}

	outputPath := strings.TrimSuffix(path, filepath.Ext(path)) + ".html"
	if err := os.WriteFile(outputPath, []byte(html), 0644); err != nil {
		fmt.Fprintf(errOut, "failed to write html: %v\n", err)
		return 1
	}
	fmt.Fprintf(out, "HTML generated at %s\n", outputPath)
	return 0
}

func runServe(args []string, out io.Writer, errOut io.Writer) int {
	if len(args) < 1 {
		fmt.Fprintln(errOut, "serve requires a markdown file path")
		return 2
	}
	path := args[0]
	addr := "127.0.0.1:0"
	cssPath := ""
	for _, arg := range args[1:] {
		if strings.HasPrefix(arg, "--addr=") {
			addr = strings.TrimPrefix(arg, "--addr=")
		}
		if strings.HasPrefix(arg, "--css=") {
			cssPath = strings.TrimPrefix(arg, "--css=")
		}
	}
	err := server.Serve(server.Config{
		Addr:    addr,
		MDPath:  path,
		CSSPath: cssPath,
	}, out, errOut)
	if err != nil {
		fmt.Fprintf(errOut, "%v\n", err)
		return 1
	}
	return 0
}

func renderWithCSS(doc invoice.Document, cssPath string) (string, error) {
	if cssPath == "" {
		return render.RenderHTML(doc)
	}
	css, err := os.ReadFile(cssPath)
	if err != nil {
		return "", err
	}
	return render.RenderHTMLWithCSS(doc, string(css))
}