package api

import (
	"context"
	"fmt"
	"net/http"
	"os"
	"strings"

	"arimelody-web/controller"
	"arimelody-web/model"
)

func Handler(app *model.AppState) http.Handler {
    mux := http.NewServeMux()

    // TODO: generate API keys on the frontend

    // ARTIST ENDPOINTS

    mux.Handle("GET /v1/artist/{id}", ServeArtist(app))
    mux.Handle("PUT /v1/artist/{id}", requireAccount(UpdateArtist(app)))
    mux.Handle("DELETE /v1/artist/{id}", requireAccount(DeleteArtist(app)))

    mux.Handle("GET /v1/artist/", ServeAllArtists(app))
    mux.Handle("GET /v1/artist", ServeAllArtists(app))
    mux.Handle("POST /v1/artist/", requireAccount(CreateArtist(app)))
    mux.Handle("POST /v1/artist", requireAccount(CreateArtist(app)))

    // RELEASE ENDPOINTS

    mux.Handle("GET /v1/music/{id}", ServeRelease(app))
    mux.Handle("PUT /v1/music/{id}", requireAccount(UpdateRelease(app)))
    mux.Handle("DELETE /v1/music/{id}", requireAccount(DeleteRelease(app)))

    mux.Handle("PUT /v1/music/{id}/tracks", requireAccount(UpdateReleaseTracks(app)))
    mux.Handle("PUT /v1/music/{id}/credits", requireAccount(UpdateReleaseCredits(app)))
    mux.Handle("PUT /v1/music/{id}/links", requireAccount(UpdateReleaseLinks(app)))

    mux.Handle("GET /v1/music/", ServeCatalog(app))
    mux.Handle("GET /v1/music", ServeCatalog(app))
    mux.Handle("POST /v1/music/", requireAccount(CreateRelease(app)))
    mux.Handle("POST /v1/music", requireAccount(CreateRelease(app)))

    // TRACK ENDPOINTS

    mux.Handle("GET /v1/track/{id}", requireAccount(ServeTrack(app)))
    mux.Handle("PUT /v1/track/{id}", requireAccount(UpdateTrack(app)))
    mux.Handle("DELETE /v1/track/{id}", requireAccount(DeleteTrack(app)))

    mux.Handle("GET /v1/track/", requireAccount(ServeAllTracks(app)))
    mux.Handle("GET /v1/track", requireAccount(ServeAllTracks(app)))
    mux.Handle("POST /v1/track/", requireAccount(CreateTrack(app)))
    mux.Handle("POST /v1/track", requireAccount(CreateTrack(app)))

    // BLOG ENDPOINTS

    mux.Handle("GET /v1/blog/{id}", ServeBlog(app))
    mux.Handle("PUT /v1/blog/{id}", requireAccount(UpdateBlog(app)))
    mux.Handle("DELETE /v1/blog/{id}", requireAccount(DeleteBlog(app)))

    mux.Handle("GET /v1/blog/", ServeAllBlogs(app))
    mux.Handle("GET /v1/blog", ServeAllBlogs(app))
    mux.Handle("POST /v1/blog/", requireAccount(CreateBlog(app)))
    mux.Handle("POST /v1/blog", requireAccount(CreateBlog(app)))

    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        session, err := getSession(app, r)
        if err != nil {
            fmt.Fprintf(os.Stderr, "WARN: Failed to get session: %v\n", err)
            http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
            return
        }
        ctx := context.WithValue(r.Context(), "session", session)
        mux.ServeHTTP(w, r.WithContext(ctx))
    })
}

func requireAccount(next http.Handler) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        session := r.Context().Value("session").(*model.Session)
        if session == nil || session.Account == nil {
            http.Error(w, http.StatusText(http.StatusUnauthorized), http.StatusUnauthorized)
            return
        }
        ctx := context.WithValue(r.Context(), "session", session)
        next.ServeHTTP(w, r.WithContext(ctx))
    })
}

func getSession(app *model.AppState, r *http.Request) (*model.Session, error) {
    var token string

    // check cookies first
    sessionCookie, err := r.Cookie(model.COOKIE_TOKEN)
    if err != nil && err != http.ErrNoCookie {
        return nil, fmt.Errorf("Failed to retrieve session cookie: %v\n", err)
    }
    if sessionCookie != nil {
        token = sessionCookie.Value
    } else {
        // check Authorization header
        token = strings.TrimPrefix(r.Header.Get("Authorization"), "Bearer ")
    }

    if token == "" { return nil, nil }

    // fetch existing session
    session, err := controller.GetSession(app.DB, token)

    if err != nil && !strings.Contains(err.Error(), "no rows") {
        return nil, fmt.Errorf("Failed to retrieve session: %v\n", err)
    }

    if session != nil {
        // TODO: consider running security checks here (i.e. user agent mismatches)
    }

    return session, nil
}