package e621

import (
	"fmt"
	"git.dragse.it/anthrove/e621-sdk-go/pkg/e621/builder"
	"git.dragse.it/anthrove/e621-sdk-go/pkg/e621/model"
	"git.dragse.it/anthrove/e621-sdk-go/pkg/e621/utils"
	_ "github.com/joho/godotenv/autoload"
	"golang.org/x/time/rate"
	"math"
	"net/http"
	"strconv"
)

// Client is the main client for interacting with the e621 API.
type Client struct {
	RequestContext model.RequestContext
}

// NewE621Client creates a new e621 client with the provided username and API key.
func NewE621Client(username string, apiKey string) Client {
	// Create a new e621 client with the given username and API key.
	return Client{
		RequestContext: model.RequestContext{
			Client:      http.Client{},
			RateLimiter: rate.NewLimiter(1, 2),
			Host:        "https://e621.net",
			UserAgent:   fmt.Sprintf("Go-e621-SDK used by %s | (made by the Anthrove Team)", username),
			Username:    username,
			APIKey:      apiKey,
		},
	}
}

// SetHost sets the API host for the client.
func (c *Client) SetHost(host string) *Client {
	// Set the API host for the client.
	c.RequestContext.Host = host
	return c
}

// SetAgentName sets the user agent name for the client.
func (c *Client) SetAgentName(userAgent string) *Client {
	// Set the user agent name for the client.
	c.RequestContext.UserAgent = userAgent
	return c
}

// GetUserByName returns a user builder for a given username.
func (c *Client) GetUserByName(username string) builder.UserBuilder {
	// Returns a user builder for the specified username.
	return builder.NewGetUserBuilder(c.RequestContext).SetUsername(username)
}

// GetUserByID returns a user builder for a given user ID.
func (c *Client) GetUserByID(userID model.UserID) builder.UserBuilder {
	// Returns a user builder for the specified user ID.
	return builder.NewGetUserBuilder(c.RequestContext).SetUsername(strconv.FormatInt(int64(userID), 10))
}

// GetFavoritesForUser returns a favorites builder for a given username.
func (c *Client) GetFavoritesForUser(username string) (builder.FavoritesBuilder, error) {
	// Returns a favorites builder for the specified username.
	user, err := builder.NewGetUserBuilder(c.RequestContext).SetUsername(username).Execute()
	if err != nil {
		return nil, err
	}
	favoritesBuilder := builder.NewGetFavoritesBuilder(c.RequestContext).SetUserID(user.ID)
	return favoritesBuilder, nil
}

// GetNFavoritesForUser retrieves a specified number of favorites for a user.
func (c *Client) GetNFavoritesForUser(n int, favoriteBuilder builder.FavoritesBuilder) ([]model.Post, error) {
	// Retrieves a specified number of favorite posts for a user.
	if n < utils.E621_MAX_POST_COUNT {
		favoriteBuilder.SetLimit(n)
	}

	var favorites []model.Post
	var page = 1
	for len(favorites) < n {
		favoriteBuilder.Page(page)
		favoriteBuilder.SetLimit(n - len(favorites))
		newFavorites, err := favoriteBuilder.Execute()
		if err != nil {
			return nil, err
		}
		if len(newFavorites) == 0 {
			break
		}
		favorites = append(favorites, newFavorites...)
		page = page + 1
	}

	return favorites, nil
}

// GetAllFavoritesForUser retrieves all favorites for a user.
func (c *Client) GetAllFavoritesForUser(favoriteBuilder builder.FavoritesBuilder) ([]model.Post, error) {
	// Retrieves all favorite posts for a user.
	return c.GetNFavoritesForUser(math.MaxInt, favoriteBuilder)
}

// GetFavoritesForUserWithTags returns a posts builder for a user's favorites with specific tags.
func (c *Client) GetFavoritesForUserWithTags(username string, tags string) builder.PostsBuilder {
	// Returns a posts builder for a user's favorites with specific tags.
	favoritesBuilder := builder.NewGetPostsBuilder(c.RequestContext).Tags(fmt.Sprintf("fav:%s %s", username, tags))
	return favoritesBuilder
}

// GetPostByID returns a post builder for a specific post ID.
func (c *Client) GetPostByID(id model.PostID) builder.PostBuilder {
	// Returns a post builder for a specific post ID.
	return builder.NewGetPostBuilder(c.RequestContext).SetPostID(id)
}

// GetPosts returns a posts builder for general post queries.
func (c *Client) GetPosts() builder.PostsBuilder {
	// Returns a posts builder for general post queries.
	return builder.NewGetPostsBuilder(c.RequestContext)
}

// GetNPosts retrieves a specified number of posts.
func (c *Client) GetNPosts(n int, postBuilder builder.PostsBuilder) ([]model.Post, error) {
	// Retrieves a specified number of posts using the provided post builder.
	if n < utils.E621_MAX_POST_COUNT {
		postBuilder.SetLimit(n)
	}

	posts, err := postBuilder.Execute()
	if err != nil {
		return nil, err
	}

	for len(posts) < n {
		lastPostID := posts[len(posts)-1].ID
		postBuilder.PageBefore(lastPostID)
		postBuilder.SetLimit(n - len(posts))
		newPosts, err := postBuilder.Execute()
		if err != nil {
			return nil, err
		}
		if len(newPosts) == 0 {
			break
		}
		posts = append(posts, newPosts...)
	}

	return posts, nil
}

// GetAllPosts retrieves all available posts using the provided post builder.
func (c *Client) GetAllPosts(postBuilder builder.PostsBuilder) ([]model.Post, error) {
	// Retrieves all available posts using the provided post builder.
	return c.GetNPosts(math.MaxInt, postBuilder)
}