package api

import (
	"encoding/json"
	"fmt"
	"io/fs"
	"net/http"
	"os"
	"path/filepath"
	"strings"
	"time"

	"arimelody.me/arimelody.me/admin"
	"arimelody.me/arimelody.me/global"
	music "arimelody.me/arimelody.me/music/controller"
	"arimelody.me/arimelody.me/music/model"
)

func ServeCatalog() http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {

        releases := []*model.Release{}
        err := global.DB.Select(&releases, "SELECT * FROM musicrelease ORDER BY release_date DESC")
        if err != nil {
            http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
            return
        }

        catalog := []model.ReleaseShorthand{}
        authorised := admin.GetSession(r) != nil
        for _, release := range releases {
            if !release.Visible && !authorised {
                continue
            }
            catalog = append(catalog, model.ReleaseShorthand{
                ID: release.ID,
                Title: release.Title,
                ReleaseType: release.ReleaseType,
                ReleaseDate: release.ReleaseDate,
                Artwork: release.Artwork,
                Buylink: release.Buylink,
            })
        }

        w.Header().Add("Content-Type", "application/json")
        err = json.NewEncoder(w).Encode(catalog)
        if err != nil {
            http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
            return
        }
    })
}

func CreateRelease() http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        if r.Method != http.MethodPost {
            http.NotFound(w, r)
            return
        }

        var release model.Release
        err := json.NewDecoder(r.Body).Decode(&release)
        if err != nil {
            http.Error(w, http.StatusText(http.StatusBadRequest), http.StatusBadRequest)
            return
        }

        if release.ID == "" {
            http.Error(w, "Release ID cannot be empty\n", http.StatusBadRequest)
            return
        }
        
        if release.Title == "" { release.Title = release.ID }
        if release.ReleaseType == "" { release.ReleaseType = model.Single }
        
        if release.ReleaseDate != time.Unix(0, 0) {
            release.ReleaseDate = time.Date(time.Now().Year(), time.Now().Month(), time.Now().Day(), 0, 0, 0, 0, time.UTC)
        }

        if release.Artwork == "" { release.Artwork = "/img/default-cover-art.png" }

        err = music.CreateRelease(global.DB, &release)
        if err != nil {
            if strings.Contains(err.Error(), "duplicate key") {
                http.Error(w, fmt.Sprintf("Release %s already exists\n", release.ID), http.StatusBadRequest)
                return
            }
            fmt.Printf("Failed to create release %s: %s\n", release.ID, err)
            http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
            return
        }

        w.Header().Add("Content-Type", "application/json")
        w.WriteHeader(http.StatusCreated)
        err = json.NewEncoder(w).Encode(release)
        if err != nil {
            fmt.Printf("WARN: Release %s created, but failed to send JSON response: %s\n", release.ID, err)
            http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
        }
    })
}

func UpdateRelease(release model.Release) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        if r.URL.Path == "/" {
            http.NotFound(w, r)
            return
        }

        segments := strings.Split(r.URL.Path[1:], "/")

        if len(segments) == 2 {
            switch segments[1] {
            case "tracks":
                UpdateReleaseTracks(release).ServeHTTP(w, r)
            case "credits":
                UpdateReleaseCredits(release).ServeHTTP(w, r)
            case "links":
                UpdateReleaseLinks(release).ServeHTTP(w, r)
            }
            return
        }
        
        if len(segments) > 2 {
            http.NotFound(w, r)
            return
        }

        err := json.NewDecoder(r.Body).Decode(&release)
        if err != nil {
            fmt.Printf("WARN: Failed to update release %s: %s\n", release.ID, err)
            http.Error(w, http.StatusText(http.StatusBadRequest), http.StatusBadRequest)
            return
        }

        if release.Artwork == "" {
            release.Artwork = "/img/default-cover-art.png"
        } else {
            if strings.Contains(release.Artwork, ";base64,") {
                var artworkDirectory = filepath.Join("uploads", "musicart")
                filename, err := HandleImageUpload(&release.Artwork, artworkDirectory, release.ID)

                // clean up files with this ID and different extensions
                err = filepath.Walk(artworkDirectory, func(path string, info fs.FileInfo, err error) error {
                    if path == filepath.Join(artworkDirectory, filename) { return nil }

                    withoutExt := strings.TrimSuffix(path, filepath.Ext(path))
                    if withoutExt != filepath.Join(artworkDirectory, release.ID) { return nil }

                    return os.Remove(path)
                })
                if err != nil {
                    fmt.Printf("WARN: Error while cleaning up artwork files: %s\n", err)
                }

                release.Artwork = fmt.Sprintf("/uploads/musicart/%s", filename)
            }
        }

        err = music.UpdateRelease(global.DB, &release)
        if err != nil {
            fmt.Printf("FATAL: Failed to update release %s: %s\n", release.ID, err)
            http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
        }
    })
}

func UpdateReleaseTracks(release model.Release) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        var trackIDs = []string{}
        err := json.NewDecoder(r.Body).Decode(&trackIDs)
        if err != nil {
            http.Error(w, http.StatusText(http.StatusBadRequest), http.StatusBadRequest)
            return
        }

        err = music.UpdateReleaseTracks(global.DB, &release, trackIDs)
        if err != nil {
            fmt.Printf("Failed to update tracks for %s: %s\n", release.ID, err)
            http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
        }
    })
}

func UpdateReleaseCredits(release model.Release) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        type creditJSON struct {
            Artist  string
            Role    string
            Primary bool
        }
        var data []creditJSON
        err := json.NewDecoder(r.Body).Decode(&data)
        if err != nil {
            http.Error(w, http.StatusText(http.StatusBadRequest), http.StatusBadRequest)
            return
        }

        var credits []model.Credit
        for _, credit := range data {
            credits = append(credits, model.Credit{
                Artist: model.Artist{
                    ID: credit.Artist,
                },
                Role: credit.Role,
                Primary: credit.Primary,
            })
        }

        err = music.UpdateReleaseCredits(global.DB, &release, credits)
        if err != nil {
            if strings.Contains(err.Error(), "duplicate key") {
                http.Error(w, "Artists may only be credited once\n", http.StatusBadRequest)
                return
            }
            fmt.Printf("Failed to update links for %s: %s\n", release.ID, err)
            http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
        }
    })
}

func UpdateReleaseLinks(release model.Release) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        if r.Method != http.MethodPut {
            http.NotFound(w, r)
            return
        }

        var links = []*model.Link{}
        err := json.NewDecoder(r.Body).Decode(&links)
        if err != nil {
            http.Error(w, http.StatusText(http.StatusBadRequest), http.StatusBadRequest)
            return
        }

        tx := global.DB.MustBegin()
        tx.MustExec("DELETE FROM musiclink WHERE release=$1", release.ID)
        for _, link := range links {
            tx.MustExec(
                "INSERT INTO musiclink "+
                "(release, name, url) "+
                "VALUES ($1, $2, $3)",
                release.ID,
                link.Name,
                link.URL)
        }
        err = tx.Commit()
        if err != nil {
            fmt.Printf("Failed to update links for %s: %s\n", release.ID, err)
            http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
        }
    })
}

func DeleteRelease(release model.Release) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        _, err := global.DB.Exec("DELETE FROM musicrelease WHERE id=$1", release.ID)
        if err != nil {
            fmt.Printf("Failed to delete release %s: %s\n", release.ID, err)
            http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
        }
    })
}