package gitea

import (
	"io"
	"net/http"
	"strings"

	"github.com/42wim/caddy-gitea/pkg/gitea"
	"github.com/caddyserver/caddy/v2"
	"github.com/caddyserver/caddy/v2/caddyconfig/caddyfile"
	"github.com/caddyserver/caddy/v2/caddyconfig/httpcaddyfile"
	"github.com/caddyserver/caddy/v2/modules/caddyhttp"
)

func init() {
	caddy.RegisterModule(Middleware{})
	httpcaddyfile.RegisterHandlerDirective("gitea", parseCaddyfile)
}

func parseCaddyfile(h httpcaddyfile.Helper) (caddyhttp.MiddlewareHandler, error) {
	var m Middleware
	err := m.UnmarshalCaddyfile(h.Dispenser)

	return m, err
}

// Middleware implements gitea plugin.
type Middleware struct {
	Client             *gitea.Client `json:"-"`
	Server             string        `json:"server,omitempty"`
	Token              string        `json:"token,omitempty"`
	GiteaPages         string        `json:"gitea_pages,omitempty"`
	GiteaPagesAllowAll string        `json:"gitea_pages_allowall,omitempty"`
	Domain             string        `json:"domain,omitempty"`
}

// CaddyModule returns the Caddy module information.
func (Middleware) CaddyModule() caddy.ModuleInfo {
	return caddy.ModuleInfo{
		ID:  "http.handlers.gitea",
		New: func() caddy.Module { return new(Middleware) },
	}
}

// Provision provisions gitea client.
func (m *Middleware) Provision(ctx caddy.Context) error {
	var err error
	m.Client, err = gitea.NewClient(m.Server, m.Token, m.GiteaPages, m.GiteaPagesAllowAll)

	return err
}

// Validate implements caddy.Validator.
func (m *Middleware) Validate() error {
	return nil
}

// UnmarshalCaddyfile unmarshals a Caddyfile.
func (m *Middleware) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
	for d.Next() {
		for n := d.Nesting(); d.NextBlock(n); {
			switch d.Val() {
			case "server":
				d.Args(&m.Server)
			case "token":
				d.Args(&m.Token)
			case "gitea_pages":
				d.Args(&m.GiteaPages)
			case "gitea_pages_allowall":
				d.Args(&m.GiteaPagesAllowAll)
			case "domain":
				d.Args(&m.Domain)
			}
		}
	}

	return nil
}

// ServeHTTP performs gitea content fetcher.
func (m Middleware) ServeHTTP(w http.ResponseWriter, r *http.Request, _ caddyhttp.Handler) error {
	// remove the domain if it's set (works fine if it's empty)
	host := strings.TrimRight(strings.TrimSuffix(r.Host, m.Domain), ".")
	h := strings.Split(host, ".")

	fp := h[0] + r.URL.Path
	ref := r.URL.Query().Get("ref")

	// if we haven't specified a domain, do not support repo.username and branch.repo.username
	if m.Domain != "" {
		switch {
		case len(h) == 2:
			fp = h[1] + "/" + h[0] + r.URL.Path
		case len(h) == 3:
			fp = h[2] + "/" + h[1] + r.URL.Path
			ref = h[0]
		}
	}

	f, err := m.Client.Open(fp, ref)
	if err != nil {
		return caddyhttp.Error(http.StatusNotFound, err)
	}

	_, err = io.Copy(w, f)

	return err
}

// Interface guards
var (
	_ caddy.Provisioner           = (*Middleware)(nil)
	_ caddy.Validator             = (*Middleware)(nil)
	_ caddyhttp.MiddlewareHandler = (*Middleware)(nil)
	_ caddyfile.Unmarshaler       = (*Middleware)(nil)
)