package pages

import (
	"bufio"
	"bytes"
	"context"
	"html/template"

	htmlfmt "github.com/alecthomas/chroma/v2/formatters/html"
	"github.com/alecthomas/chroma/v2/lexers"
	"github.com/alecthomas/chroma/v2/styles"
	"github.com/carlmjohnson/requests"
	"github.com/gofiber/fiber/v2"
)

// FileView is the file view page
func FileView(c *fiber.Ctx) error {
	var file string
	url := "https://raw.githubusercontent.com/" + c.Params("user") + "/" + c.Params("repo") + "/" + c.Params("branch") + "/" + c.Params("file")
	err := requests.
		URL(url).
		ToString(&file).
		Fetch(context.Background())
	if err != nil {
		return c.Status(404).Render("error", fiber.Map{
			"error": err,
		})
	}

	lexer := lexers.Match(c.Params("file"))
	if lexer == nil {
		lexer = lexers.Fallback
	}

	formatter := htmlfmt.New(
		htmlfmt.WithClasses(true),
		htmlfmt.WithLineNumbers(true),
		htmlfmt.PreventSurroundingPre(false),
	)

	buf := bytes.Buffer{}
	writer := bufio.NewWriter(&buf)
	style := styles.Get("native")

	tokens, err := lexer.Tokenise(nil, file)
	if err != nil {
		return c.Status(500).Render("error", fiber.Map{
			"error": err,
		})
	}
	formatter.Format(writer, style, tokens)

	cssbuf := bytes.Buffer{}
	cssw := bufio.NewWriter(&cssbuf)
	formatter.WriteCSS(cssw, style)

	writer.Flush()
	cssw.Flush()

	return c.Render("file", fiber.Map{
		"file":     template.HTML(buf.String()),
		"css":      template.CSS(cssbuf.String()),
		"fullname": c.Params("user") + "/" + c.Params("repo"),
		"name":     c.Params("file"),
		"branch":   c.Params("branch"),
	})
}