package reddit

import (
	"context"
	"errors"
	"net/http"
	"net/url"
	"strings"

	"github.com/google/go-querystring/query"
)

// PostService handles communication with the post
// related methods of the Reddit API.
//
// Reddit API docs: https://www.reddit.com/dev/api/#section_links_and_comments
type PostService service

type submittedLinkRoot struct {
	JSON struct {
		Data *Submitted `json:"data,omitempty"`
	} `json:"json"`
}

// Submitted is a newly submitted post on Reddit.
type Submitted struct {
	ID     string `json:"id,omitempty"`
	FullID string `json:"name,omitempty"`
	URL    string `json:"url,omitempty"`
}

// SubmitTextOptions are options used for text posts.
type SubmitTextOptions struct {
	Subreddit string `url:"sr,omitempty"`
	Title     string `url:"title,omitempty"`
	Text      string `url:"text,omitempty"`

	FlairID   string `url:"flair_id,omitempty"`
	FlairText string `url:"flair_text,omitempty"`

	SendReplies *bool `url:"sendreplies,omitempty"`
	NSFW        bool  `url:"nsfw,omitempty"`
	Spoiler     bool  `url:"spoiler,omitempty"`
}

// SubmitLinkOptions are options used for link posts.
type SubmitLinkOptions struct {
	Subreddit string `url:"sr,omitempty"`
	Title     string `url:"title,omitempty"`
	URL       string `url:"url,omitempty"`

	FlairID   string `url:"flair_id,omitempty"`
	FlairText string `url:"flair_text,omitempty"`

	SendReplies *bool `url:"sendreplies,omitempty"`
	Resubmit    bool  `url:"resubmit,omitempty"`
	NSFW        bool  `url:"nsfw,omitempty"`
	Spoiler     bool  `url:"spoiler,omitempty"`
}

func (s *PostService) submit(ctx context.Context, v interface{}) (*Submitted, *Response, error) {
	path := "api/submit"

	form, err := query.Values(v)
	if err != nil {
		return nil, nil, err
	}
	form.Set("api_type", "json")

	req, err := s.client.NewRequestWithForm(http.MethodPost, path, form)
	if err != nil {
		return nil, nil, err
	}

	root := new(submittedLinkRoot)
	resp, err := s.client.Do(ctx, req, root)
	if err != nil {
		return nil, resp, err
	}

	return root.JSON.Data, resp, nil
}

// SubmitText submits a text post.
func (s *PostService) SubmitText(ctx context.Context, opts SubmitTextOptions) (*Submitted, *Response, error) {
	type submit struct {
		SubmitTextOptions
		Kind string `url:"kind,omitempty"`
	}
	return s.submit(ctx, &submit{opts, "self"})
}

// SubmitLink submits a link post.
func (s *PostService) SubmitLink(ctx context.Context, opts SubmitLinkOptions) (*Submitted, *Response, error) {
	type submit struct {
		SubmitLinkOptions
		Kind string `url:"kind,omitempty"`
	}
	return s.submit(ctx, &submit{opts, "link"})
}

// Edit edits a post.
func (s *PostService) Edit(ctx context.Context, id string, text string) (*Post, *Response, error) {
	path := "api/editusertext"

	form := url.Values{}
	form.Set("api_type", "json")
	form.Set("return_rtjson", "true")
	form.Set("thing_id", id)
	form.Set("text", text)

	req, err := s.client.NewRequestWithForm(http.MethodPost, path, form)
	if err != nil {
		return nil, nil, err
	}

	root := new(Post)
	resp, err := s.client.Do(ctx, req, root)
	if err != nil {
		return nil, resp, err
	}

	return root, resp, nil
}

// Hide hides posts.
func (s *PostService) Hide(ctx context.Context, ids ...string) (*Response, error) {
	if len(ids) == 0 {
		return nil, errors.New("must provide at least 1 id")
	}

	path := "api/hide"

	form := url.Values{}
	form.Set("id", strings.Join(ids, ","))

	req, err := s.client.NewRequestWithForm(http.MethodPost, path, form)
	if err != nil {
		return nil, err
	}

	return s.client.Do(ctx, req, nil)
}

// Unhide unhides posts.
func (s *PostService) Unhide(ctx context.Context, ids ...string) (*Response, error) {
	if len(ids) == 0 {
		return nil, errors.New("must provide at least 1 id")
	}

	path := "api/unhide"

	form := url.Values{}
	form.Set("id", strings.Join(ids, ","))

	req, err := s.client.NewRequestWithForm(http.MethodPost, path, form)
	if err != nil {
		return nil, err
	}

	return s.client.Do(ctx, req, nil)
}

// MarkNSFW marks a post as NSFW.
func (s *PostService) MarkNSFW(ctx context.Context, id string) (*Response, error) {
	path := "api/marknsfw"

	form := url.Values{}
	form.Set("id", id)

	req, err := s.client.NewRequestWithForm(http.MethodPost, path, form)
	if err != nil {
		return nil, err
	}

	return s.client.Do(ctx, req, nil)
}

// UnmarkNSFW unmarks a post as NSFW.
func (s *PostService) UnmarkNSFW(ctx context.Context, id string) (*Response, error) {
	path := "api/unmarknsfw"

	form := url.Values{}
	form.Set("id", id)

	req, err := s.client.NewRequestWithForm(http.MethodPost, path, form)
	if err != nil {
		return nil, err
	}

	return s.client.Do(ctx, req, nil)
}

// Spoiler marks a post as a spoiler.
func (s *PostService) Spoiler(ctx context.Context, id string) (*Response, error) {
	path := "api/spoiler"

	form := url.Values{}
	form.Set("id", id)

	req, err := s.client.NewRequestWithForm(http.MethodPost, path, form)
	if err != nil {
		return nil, err
	}

	return s.client.Do(ctx, req, nil)
}

// Unspoiler unmarks a post as a spoiler.
func (s *PostService) Unspoiler(ctx context.Context, id string) (*Response, error) {
	path := "api/unspoiler"

	form := url.Values{}
	form.Set("id", id)

	req, err := s.client.NewRequestWithForm(http.MethodPost, path, form)
	if err != nil {
		return nil, err
	}

	return s.client.Do(ctx, req, nil)
}

// Sticky stickies a post in its subreddit.
// When bottom is true, the post will be set as the bottom sticky (the 2nd one).
// If no top sticky exists, the post will become the top sticky regardless.
// When attempting to sticky a post that's already stickied, it will return a 409 Conflict error.
func (s *PostService) Sticky(ctx context.Context, id string, bottom bool) (*Response, error) {
	path := "api/set_subreddit_sticky"

	form := url.Values{}
	form.Set("api_type", "json")
	form.Set("id", id)
	form.Set("state", "true")
	if !bottom {
		form.Set("num", "1")
	}

	req, err := s.client.NewRequestWithForm(http.MethodPost, path, form)
	if err != nil {
		return nil, err
	}

	return s.client.Do(ctx, req, nil)
}

// Unsticky unstickies a post in its subreddit.
func (s *PostService) Unsticky(ctx context.Context, id string) (*Response, error) {
	path := "api/set_subreddit_sticky"

	form := url.Values{}
	form.Set("api_type", "json")
	form.Set("id", id)
	form.Set("state", "false")

	req, err := s.client.NewRequestWithForm(http.MethodPost, path, form)
	if err != nil {
		return nil, err
	}

	return s.client.Do(ctx, req, nil)
}

// PinToProfile pins one of your posts to your profile.
// TODO: very inconsistent behaviour, not sure I'm ready to include this parameter yet.
// The pos parameter should be a number between 1-4 (inclusive), indicating the position at which
// the post should appear on your profile.
// Note: The position will be bumped upward if there's space. E.g. if you only have 1 pinned post,
// and you try to pin another post to position 3, it will be pinned at 2.
// When attempting to pin a post that's already pinned, it will return a 409 Conflict error.
func (s *PostService) PinToProfile(ctx context.Context, id string) (*Response, error) {
	path := "api/set_subreddit_sticky"

	// if pos < 1 {
	// 	pos = 1
	// }
	// if pos > 4 {
	// 	pos = 4
	// }

	form := url.Values{}
	form.Set("api_type", "json")
	form.Set("id", id)
	form.Set("state", "true")
	form.Set("to_profile", "true")
	// form.Set("num", fmt.Sprint(pos))

	req, err := s.client.NewRequestWithForm(http.MethodPost, path, form)
	if err != nil {
		return nil, err
	}

	return s.client.Do(ctx, req, nil)
}

// UnpinFromProfile unpins one of your posts from your profile.
func (s *PostService) UnpinFromProfile(ctx context.Context, id string) (*Response, error) {
	path := "api/set_subreddit_sticky"

	form := url.Values{}
	form.Set("api_type", "json")
	form.Set("id", id)
	form.Set("state", "false")
	form.Set("to_profile", "true")

	req, err := s.client.NewRequestWithForm(http.MethodPost, path, form)
	if err != nil {
		return nil, err
	}

	return s.client.Do(ctx, req, nil)
}