package builder

import (
	"context"
	"git.dragse.it/anthrove/e621-sdk-go/pkg/e621/endpoints"
	"git.dragse.it/anthrove/e621-sdk-go/pkg/e621/model"
	"git.dragse.it/anthrove/e621-sdk-go/pkg/e621/utils"
	"strconv"
)

// PostsBuilder represents a builder for constructing queries to retrieve posts.
type PostsBuilder interface {
	// Tags sets the query to search for posts with specific tags.
	Tags(tags string) PostsBuilder
	// PageAfter sets the query to retrieve posts after a specific post ID.
	PageAfter(postID model.PostID) PostsBuilder
	// PageBefore sets the query to retrieve posts before a specific post ID.
	PageBefore(postID model.PostID) PostsBuilder
	// PageNumber sets the query to retrieve posts on a specific page number.
	PageNumber(number int) PostsBuilder
	// SetLimit sets the maximum number of posts to retrieve.
	SetLimit(limitUser int) PostsBuilder
	// Execute sends the constructed query and returns a slice of posts and an error, if any.
	Execute() ([]model.Post, error)
}

// NewGetPostsBuilder creates a new instance of PostsBuilder with the provided RequestContext.
//
// Parameters:
//   - requestContext: The context for the API request, including the host, user agent, username, and API key.
//
// Returns:
//   - PostsBuilder: An instance of the PostsBuilder interface.
func NewGetPostsBuilder(requestContext model.RequestContext) PostsBuilder {
	postBuilder := &getPosts{
		requestContext: requestContext,
		query:          make(map[string]string),
	}

	return postBuilder.SetLimit(utils.E621_MAX_POST_COUNT)
}

// getPosts is an implementation of the PostsBuilder interface.
type getPosts struct {
	requestContext model.RequestContext
	query          map[string]string
}

// Tags sets the query to search for posts with specific tags.
//
// Parameters:
//   - tags: The tags to search for in the posts.
//
// Returns:
//   - PostsBuilder: The instance of the PostsBuilder for method chaining.
func (g *getPosts) Tags(tags string) PostsBuilder {
	g.query["tags"] = tags
	return g
}

// PageAfter sets the query to retrieve posts after a specific post ID.
//
// Parameters:
//   - postID: The ID of the post after which to retrieve other posts.
//
// Returns:
//   - PostsBuilder: The instance of the PostsBuilder for method chaining.
func (g *getPosts) PageAfter(postID model.PostID) PostsBuilder {
	g.query["page"] = "a" + strconv.Itoa(int(postID))
	return g
}

// PageBefore sets the query to retrieve posts before a specific post ID.
//
// Parameters:
//   - postID: The ID of the post before which to retrieve other posts.
//
// Returns:
//   - PostsBuilder: The instance of the PostsBuilder for method chaining.
func (g *getPosts) PageBefore(postID model.PostID) PostsBuilder {
	g.query["page"] = "b" + strconv.Itoa(int(postID))
	return g
}

// PageNumber sets the query to retrieve posts on a specific page number.
//
// Parameters:
//   - number: The page number to retrieve posts from.
//
// Returns:
//   - PostsBuilder: The instance of the PostsBuilder for method chaining.
func (g *getPosts) PageNumber(number int) PostsBuilder {
	g.query["page"] = strconv.Itoa(number)
	return g
}

// SetLimit sets the maximum number of posts to retrieve.
//
// Parameters:
//   - limitUser: The maximum number of posts to retrieve.
//
// Returns:
//   - PostsBuilder: The instance of the PostsBuilder for method chaining.
func (g *getPosts) SetLimit(limitUser int) PostsBuilder {
	g.query["limit"] = strconv.Itoa(limitUser)
	return g
}

// Execute sends the constructed query and returns a slice of posts and an error, if any.
//
// Returns:
//   - []model.Post: A slice of posts.
//   - error: An error, if any, encountered during the API request or response handling.
func (g *getPosts) Execute() ([]model.Post, error) {
	if g.requestContext.RateLimiter != nil {
		err := g.requestContext.RateLimiter.Wait(context.Background())
		if err != nil {
			return nil, err
		}
	}
	posts, err := endpoints.GetPosts(g.requestContext, g.query)
	if err != nil {
		return nil, err
	}
	return posts, err
}