package gitea

import (
	"context"
	"encoding/json"
	"fmt"
	"net/http"
	"net/url"
	"strings"
	"time"

	"sgg-ai-skill-manager/internal/domain"
)

const (
	AuthPassword = "password"
	AuthToken    = "token"
)

type Auth struct {
	Type     string
	Username string
	Secret   string
}

type Client struct {
	baseURL    string
	auth       Auth
	httpClient *http.Client
}

type apiRepo struct {
	Name          string `json:"name"`
	FullName      string `json:"full_name"`
	Description   string `json:"description"`
	CloneURL      string `json:"clone_url"`
	SSHURL        string `json:"ssh_url"`
	DefaultBranch string `json:"default_branch"`
	UpdatedAt     string `json:"updated_at"`
}

type apiUser struct {
	UserName string `json:"username"`
}

func NewClient(baseURL string, auth Auth) *Client {
	return &Client{
		baseURL: strings.TrimRight(baseURL, "/"),
		auth: auth,
		httpClient: &http.Client{Timeout: 20 * time.Second},
	}
}

func (c *Client) ListOrgSkills(ctx context.Context, org string) ([]domain.RemoteSkill, error) {
	var skills []domain.RemoteSkill
	for page := 1; ; page++ {
		var repos []apiRepo
		endpoint := fmt.Sprintf("/api/v1/orgs/%s/repos?page=%d&limit=50", url.PathEscape(org), page)
		if err := c.getJSON(ctx, endpoint, &repos); err != nil {
			return nil, err
		}
		if len(repos) == 0 {
			break
		}
		for _, repo := range repos {
			hasSkill, err := c.HasRootSkill(ctx, org, repo.Name, repo.DefaultBranch)
			if err != nil {
				skills = append(skills, domain.RemoteSkill{
					Name:     repo.Name,
					FullName: repo.FullName,
					Status:   "check_failed",
					Error:    err.Error(),
				})
				continue
			}
			if !hasSkill {
				continue
			}
			skills = append(skills, domain.RemoteSkill{
				Name:          repo.Name,
				FullName:      repo.FullName,
				Description:   repo.Description,
				CloneURL:      repo.CloneURL,
				SSHURL:        repo.SSHURL,
				DefaultBranch: repo.DefaultBranch,
				UpdatedAt:     repo.UpdatedAt,
				Status:        "remote",
			})
		}
		if len(repos) < 50 {
			break
		}
	}
	return skills, nil
}

func (c *Client) HasRootSkill(ctx context.Context, org, repo, ref string) (bool, error) {
	endpoint := fmt.Sprintf(
		"/api/v1/repos/%s/%s/contents/SKILL.md",
		url.PathEscape(org),
		url.PathEscape(repo),
	)
	if ref != "" {
		endpoint += "?ref=" + url.QueryEscape(ref)
	}
	req, err := c.newRequest(ctx, http.MethodGet, endpoint)
	if err != nil {
		return false, err
	}
	resp, err := c.httpClient.Do(req)
	if err != nil {
		return false, err
	}
	defer resp.Body.Close()
	if resp.StatusCode == http.StatusNotFound {
		return false, nil
	}
	if resp.StatusCode >= 200 && resp.StatusCode < 300 {
		return true, nil
	}
	return false, fmt.Errorf("check SKILL.md failed: %s", resp.Status)
}

func (c *Client) TestConnection(ctx context.Context, org string) (domain.TestConnectionResult, error) {
	var user apiUser
	if err := c.getJSON(ctx, "/api/v1/user", &user); err != nil {
		return domain.TestConnectionResult{}, err
	}
	req, err := c.newRequest(ctx, http.MethodGet, "/api/v1/orgs/"+url.PathEscape(org))
	if err != nil {
		return domain.TestConnectionResult{}, err
	}
	resp, err := c.httpClient.Do(req)
	if err != nil {
		return domain.TestConnectionResult{}, err
	}
	defer resp.Body.Close()
	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
		return domain.TestConnectionResult{}, fmt.Errorf("org access failed: %s", resp.Status)
	}
	return domain.TestConnectionResult{
		OK:       true,
		Message:  "connected",
		Username: user.UserName,
		Org:      org,
	}, nil
}

func (c *Client) getJSON(ctx context.Context, endpoint string, target any) error {
	req, err := c.newRequest(ctx, http.MethodGet, endpoint)
	if err != nil {
		return err
	}
	resp, err := c.httpClient.Do(req)
	if err != nil {
		return err
	}
	defer resp.Body.Close()
	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
		return fmt.Errorf("gitea request failed: %s", resp.Status)
	}
	return json.NewDecoder(resp.Body).Decode(target)
}

func (c *Client) newRequest(ctx context.Context, method, endpoint string) (*http.Request, error) {
	req, err := http.NewRequestWithContext(ctx, method, c.baseURL+endpoint, nil)
	if err != nil {
		return nil, err
	}
	if c.auth.Type == AuthToken {
		req.Header.Set("Authorization", "token "+c.auth.Secret)
	} else if c.auth.Username != "" || c.auth.Secret != "" {
		req.SetBasicAuth(c.auth.Username, c.auth.Secret)
	}
	req.Header.Set("Accept", "application/json")
	return req, nil
}